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Chakraborty LS, Le Maitre CL, Chahine NO, Fields AJ, Gawri R, Giers MB, Smith LJ, Tang SY, Zehra U, Haglund L, Samartzis D, Martin JT. Impact of the COVID-19 pandemic on the productivity and career prospects of musculoskeletal researchers. J Orthop Res 2024. [PMID: 38678396 DOI: 10.1002/jor.25866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 03/27/2024] [Accepted: 04/15/2024] [Indexed: 04/30/2024]
Abstract
Academic researchers faced a multitude of challenges posed by the COVID-19 pandemic, including widespread shelter-in-place orders, workplace closures, and cessation of in-person meetings and laboratory activities. The extent to which these challenges impacted musculoskeletal researchers, specifically, is unknown. We developed an anonymous web-based survey to determine the pandemic's impact on research productivity and career prospects among musculoskeletal research trainees and faculty. There were 116 musculoskeletal (MSK) researchers with varying demographic backgrounds who completed the survey. Of respondents, 48.3% (n = 56) believed that musculoskeletal funding opportunities decreased because of COVID-19, with faculty members more likely to hold this belief compared to nonfaculty researchers (p = 0.008). Amongst MSK researchers, 88.8% (n = 103) reported research activity was limited by COVID-19, and 92.2% (n = 107) of researchers reported their research was not able to be refocused on COVID-19-related topics, with basic science researchers less likely to be able to refocus their research compared to clinical researchers (p = 0.030). Additionally, 47.4% (n = 55) reported a decrease in manuscript submissions since the onset of the pandemic. Amongst 51 trainee researchers, 62.8% (n = 32) reported a decrease in job satisfaction directly attributable to the COVID-19 pandemic. In summary, study findings indicated that MSK researchers struggled to overcome challenges imposed by the pandemic, reporting declines in funding opportunities, research productivity, and manuscript submission. Trainee researchers experienced significant disruptions to critical research activities and worsening job satisfaction. Our findings motivate future efforts to support trainees in developing their careers and target the recovery of MSK research from the pandemic stall.
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Affiliation(s)
- Lauren S Chakraborty
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
| | - Christine L Le Maitre
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
| | - Aaron J Fields
- Department of Orthopaedic Surgery, University of California in San Francisco, San Francisco, California, USA
| | - Rahul Gawri
- Division of Orthopaedic Surgery, Department of Surgery, McGill University, Montréal, Quebec, Canada
| | - Morgan B Giers
- School of Chemical, Biological & Environmental Engineering, Oregon State University, Corvallis, Oregon, USA
| | - Lachlan J Smith
- Departments of Orthopaedic Surgery and Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Simon Y Tang
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, USA
| | - Uruj Zehra
- Department of Anatomy, University of Health Sciences, Lahore, Pakistan
| | - Lisbet Haglund
- Division of Orthopaedic Surgery, Department of Surgery, McGill University, Montréal, Quebec, Canada
| | - Dino Samartzis
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
| | - John T Martin
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
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Lisiewski LE, Jacobsen HE, Viola DCM, Kenawy HM, Kiridly DN, Chahine NO. Intradiscal inflammatory stimulation induces spinal pain behavior and intervertebral disc degeneration in vivo. FASEB J 2024; 38:e23364. [PMID: 38091247 PMCID: PMC10795732 DOI: 10.1096/fj.202300227r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 10/30/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023]
Abstract
Degeneration of the intervertebral disc (IVD) results in a range of symptomatic (i.e., painful) and asymptomatic experiences. Components of the degenerative environment, including structural disruption and inflammatory cytokine production, often correlate with pain severity. However, the role of inflammation in the activation of pain and degenerative changes has been complex to delineate. The most common IVD injury model is puncture; however, it initiates structural damage that is not representative of the natural degenerative cascade. In this study, we utilized in vivo injection of lipopolysaccharide (LPS), a pro-inflammatory stimulus, into rat caudal IVDs using 33G needles to induce inflammatory activation without the physical tissue disruption caused by puncture using larger needles. LPS injection increased gene expression of pro-inflammatory cytokines (Tnfa, Il1b) and macrophage markers (Inos, Arg1), supported by immunostaining of macrophages (CD68, CCR7, Arg1) and systemic changes in blood cytokine and chemokine levels. Disruption of the IVD structural integrity after LPS injection was also evident through changes in histological grading, disc height, and ECM biochemistry. Ultimately, intradiscal inflammatory stimulation led to local mechanical hyperalgesia, demonstrating that pain can be initiated by inflammatory stimulation of the IVD. Gene expression of nociceptive markers (Ngf, Bdnf, Cgrp) and immunostaining for neuron ingrowth (PGP9.5) and sensitization (CGRP) in the IVD were also shown, suggesting a mechanism for the pain exhibited. To our knowledge, this rat IVD injury model is the first to demonstrate local pain behavior resulting from inflammatory stimulation of caudal IVDs. Future studies will examine the mechanistic contributions of inflammation in mediating pain.
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Affiliation(s)
- Lauren E. Lisiewski
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| | - Hayley E. Jacobsen
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| | - Dan C. M. Viola
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| | - Hagar M. Kenawy
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| | - Daniel N. Kiridly
- Department of Orthopedic Surgery, Northwell Health, Manhasset, NY, United States
| | - Nadeen O. Chahine
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
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Kenawy HM, Nuñez MI, Morales X, Lisiewski LE, Burt KG, Kim MKM, Campos L, Kiridly N, Hung CT, Chahine NO. Sex differences in the biomechanical and biochemical responses of caudal rat intervertebral discs to injury. JOR Spine 2023; 6:e1299. [PMID: 38156061 PMCID: PMC10751974 DOI: 10.1002/jsp2.1299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 09/26/2023] [Accepted: 10/19/2023] [Indexed: 12/30/2023] Open
Abstract
Background Intervertebral disc degeneration (IDD) is a major cause of low back pain (LBP) worldwide. Sexual dimorphism, or sex-based differences, appear to exist in the severity of LBP. However, it is unknown if there are sex-based differences in the inflammatory, biomechanical, biochemical, and histological responses of intervertebral discs (IVDs). Methods Caudal (Coccygeal/Co) bone-disc-bone motion segments were isolated from multiple spinal levels (Co8 to Co14) of male and female Sprague-Dawley rats. Changes in motion segment biomechanics and extracellular matrix (ECM) biochemistry (glycosaminoglycan [GAG], collagen [COL], water, and DNA content) were evaluated at baseline and in response to chemical insult (lipopolysaccharide [LPS]) or puncture injury ex vivo. We also investigated the contributions of Toll-like receptor (TLR4) signaling on responses to LPS or puncture injury ex vivo, using a small molecule TLR4 inhibitor, TAK-242. Results Findings indicate that IVD motion segments from female donors had greater nitric oxide (NO) release in LPS groups compared to male donors. HMGB1 release was increased in punctured discs, but not LPS injured discs, with no sex effect. Although both male and female discs exhibited reductions in dynamic moduli in response to LPS and puncture injuries, dynamic moduli from female donors were higher than male donors across all groups. In uninjured (baseline) samples, a significant sex effect was observed in nucleus pulposus (NP) DNA and water content. Female annulus fibrosus (AF) also had higher DNA, GAG, and COL content (normalized by dry weight), but lower water content than male AF. Additional injury- and sex-dependent effects were observed in AF GAG/DNA and COL/DNA content. Finally, TAK-242 improved the dynamic modulus of female but not male punctured discs. Conclusions Our findings demonstrate that there are differences in rat IVD motion segments based on sex, and that the response to injury in inflammatory, biomechanical, biochemical, and histological outcomes also exhibit sex differences. TLR4 inhibition protected against loss of mechanical integrity of puncture-injured IVD motion segments, with differences responses based on donor sex.
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Affiliation(s)
- Hagar M. Kenawy
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - María I. Nuñez
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - Xóchitl Morales
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | | | - Kevin G. Burt
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - Min Kyu M. Kim
- Department of Orthopedic SurgeryColumbia University Irving Medical CenterNew YorkNew YorkUSA
| | - Leonardo Campos
- Department of Orthopedic SurgeryColumbia University Irving Medical CenterNew YorkNew YorkUSA
| | - Nadia Kiridly
- Department of Orthopedic SurgeryColumbia University Irving Medical CenterNew YorkNew YorkUSA
| | - Clark T. Hung
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
- Department of Orthopedic SurgeryColumbia University Irving Medical CenterNew YorkNew YorkUSA
| | - Nadeen O. Chahine
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
- Department of Orthopedic SurgeryColumbia University Irving Medical CenterNew YorkNew YorkUSA
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Burt KG, Viola DC, Lisiewski LE, Lombardi JM, Amorosa LF, Chahine NO. An in vivo model of ligamentum flavum hypertrophy from early-stage inflammation to fibrosis. JOR Spine 2023; 6:e1260. [PMID: 37780823 PMCID: PMC10540830 DOI: 10.1002/jsp2.1260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 03/10/2023] [Accepted: 04/25/2023] [Indexed: 10/03/2023] Open
Abstract
Multi-joint disease pathologies in the lumbar spine, including ligamentum flavum (LF) hypertrophy and intervertebral disc (IVD) bulging or herniation contribute to lumbar spinal stenosis (LSS), a highly prevalent condition characterized by symptomatic narrowing of the spinal canal. Clinical hypertrophic LF is characterized by a loss of elastic fibers and increase in collagen fibers, resulting in fibrotic thickening and scar formation. In this study, we created an injury model to test the hypothesis that LF needle scrape injury in the rat will result in hypertrophy of the LF characterized by altered tissue geometry, matrix organization, composition and inflammation. An initial pilot study was conducted to evaluate effect of needle size. Results indicate that LF needle scrape injury using a 22G needle produced upregulation of the pro-inflammatory cytokine Il6 at 1 week post injury, and increased expression of Ctgf and Tgfb1 at 8 weeks post injury, along with persistent presence of infiltrating macrophages at 1, 3, and 8 weeks post injury. LF integrity was also altered, evidenced by increases in LF tissue thickness and loss of elastic tissue by 8 weeks post injury. Persistent LF injury also produced multi-joint effects in the lumbar IVD, including disc height loss at the injury and adjacent to injury level, with degenerative IVD changes observed in the adjacent level. These results demonstrate that LF scrape injury in the rat produces structural and molecular features of LF hypertrophy and IVD height and histological changes, dependent on level. This model may be useful for testing of therapeutic interventions for treatment of LSS and IVD degeneration associated with LF hypertrophy.
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Affiliation(s)
- Kevin G. Burt
- Department of Orthopedic SurgeryColumbia UniversityNew YorkNew YorkUSA
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - Dan C. Viola
- Department of Orthopedic SurgeryColumbia UniversityNew YorkNew YorkUSA
| | - Lauren E. Lisiewski
- Department of Orthopedic SurgeryColumbia UniversityNew YorkNew YorkUSA
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | | | | | - Nadeen O. Chahine
- Department of Orthopedic SurgeryColumbia UniversityNew YorkNew YorkUSA
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
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Burt KG, Kim MKM, Viola DC, Abraham AC, Chahine NO. Nuclear Factor Kappa B Over-Activation in the Intervertebral Disc Leads to Macrophage Recruitment and Severe Disc Degeneration. bioRxiv 2023:2023.08.07.552274. [PMID: 37609194 PMCID: PMC10441339 DOI: 10.1101/2023.08.07.552274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Objective Low back pain (LBP) is the leading cause of global disability and is thought to be driven primarily by intervertebral disc (IVD) degeneration (DD). Persistent upregulation of catabolic enzymes and inflammatory mediators have been associated with severe cases of DD. Nuclear factor kappa B (NF-κB) is a master transcription regulator of immune responses and is over expressed during inflammatory-driven musculoskeletal diseases, including DD. However, its role in triggering DD is unknown. Therefore, this study investigated the effect of NF-κB pathway over-activation on IVD integrity and DD pathology. Methods Using skeletally mature mouse model, we genetically targeted IVD cells for canonical NF-κB pathway activation via expression of a constitutively active form of inhibitor of κB kinase B (IKKβ), and assessed changes in IVD cellularity, structural integrity including histology, disc height, and extracellular matrix (ECM) biochemistry, biomechanics, expression of inflammatory, catabolic, and neurotropic mediators, and changes in macrophage subsets, longitudinally up to 6-months post activation. Results Prolonged NF-κB activation led to severe structural degeneration, with a loss of glycosaminoglycan (GAG) content and complete loss of nucleus pulposus (NP) cellularity. Structural and compositional changes decreased IVD height and compressive mechanical properties with prolonged NF-κB activation. These alterations were accompanied by increases in gene expression of inflammatory molecules ( Il1b, Il6, Nos2 ), chemokines ( Mcp1 , Mif ), catabolic enzymes ( Mmp3, Mmp9, Adamts4 ), and neurotrophic factors ( Bdnf , Ngf ) within IVD tissue. Increased recruitment of activated F4/80 + macrophages exhibited a greater abundance of pro-inflammatory (CD38 + ) over inflammatory-resolving (CD206 + ) macrophage subsets in the IVD, with temporal changes in the relative abundance of macrophage subsets over time, providing evidence for temporal regulation of macrophage polarization in DD in vivo, where macrophages participate in resolving the inflammatory cascade but promote fibrotic transformation of the IVD matrix. We further show that NF-κB driven secretory factors from IVD cells increase macrophage migration and inflammatory activation, and that the secretome of inflammatory-resolving macrophages mitigates effects of NF-κB overactivation. Conclusion Overall the observed results suggest prolonged NF-κB activation can induce severe DD, acting through increases in inflammatory cytokines, chemotactic proteins, catabolic enzymes, and the recruitment and inflammatory activation of a macrophage cell populations, that can be mitigated with inflammatory-resolving macrophage secretome.
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Martin JT, Asimakopoulos D, Hornung AL, Toro SJ, Le Maitre CL, Chahine NO, Fields AJ, Gawri R, Giers MB, Smith LJ, Tang SY, Zehra U, Haglund L, Samartzis D. Bullying, harassment, and discrimination of musculoskeletal researchers and the impact of the COVID-19 pandemic: an international study. Eur Spine J 2023; 32:1861-1875. [PMID: 37014436 PMCID: PMC10071222 DOI: 10.1007/s00586-023-07684-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/11/2023] [Accepted: 03/23/2023] [Indexed: 04/05/2023]
Abstract
PURPOSE Bullying, harassment, and discrimination (BHD) are prevalent in academic, scientific, and clinical departments, particularly orthopedic surgery, and can have lasting effects on victims. As it is unclear how BHD affects musculoskeletal (MSK) researchers, the following study assessed BHD in the MSK research community and whether the COVID-19 pandemic, which caused hardships in other industries, had an impact. METHODS A web-based anonymous survey was developed in English by ORS Spine Section members to assess the impact of COVID-19 on MSK researchers in North America, Europe, and Asia, which included questions to evaluate the personal experience of researchers regarding BHD. RESULTS 116 MSK researchers completed the survey. Of respondents, 34.5% (n = 40) focused on spine, 30.2% (n = 35) had multiple areas of interest, and 35.3% (n = 41) represented other areas of MSK research. BHD was observed by 26.7% (n = 31) of respondents and personally experienced by 11.2% (n = 13), with mid-career faculty both observing and experiencing the most BHD. Most who experienced BHD (53.8%, n = 7) experienced multiple forms. 32.8% (n = 38) of respondents were not able to speak out about BHD without fear of repercussions, with 13.8% (n = 16) being unsure about this. Of those who observed BHD, 54.8% (n = 17) noted that the COVID-19 pandemic had no impact on their observations. CONCLUSIONS To our knowledge, this is the first study to address the prevalence and determinants of BHD among MSK researchers. MSK researchers experienced and observed BHD, while many were not comfortable reporting and discussing violations to their institution. The COVID-19 pandemic had mixed-effects on BHD. Awareness and proactive policy changes may be warranted to reduce/eliminate the occurrence of BHD in this community.
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Affiliation(s)
- John T Martin
- Department of Orthopedic Surgery, Orthopedic Building, Rush University Medical Center, 1611 W. Harrison Street, Chicago, IL, 60612, USA
- International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, USA
| | | | - Alexander L Hornung
- Department of Orthopedic Surgery, Orthopedic Building, Rush University Medical Center, 1611 W. Harrison Street, Chicago, IL, 60612, USA
- International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, USA
| | - Sheila J Toro
- Department of Orthopedic Surgery, Orthopedic Building, Rush University Medical Center, 1611 W. Harrison Street, Chicago, IL, 60612, USA
- International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, USA
| | | | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, New York, USA
| | - Aaron J Fields
- Department of Orthopaedic Surgery, University of California in San Francisco, San Francisco, USA
| | - Rahul Gawri
- Department of Surgery, The Orthopaedic Research Laboratory Montreal General Hospital, McGill University, 1650 Cedar Avenue, Room C10.148.2, Montreal, QC, H3G 1A4, Canada
| | - Morgan B Giers
- School of Chemical, Biological & Environmental Engineering, Oregon State University, Corvallis, USA
| | - Lachlan J Smith
- Departments of Orthopaedic Surgery and Neurosurgery, University of Pennsylvania, Philadelphia, USA
| | - Simon Y Tang
- Department of Orthopaedic Surgery, Washington University, St. Louis, USA
| | - Uruj Zehra
- Department of Anatomy, University of Health Sciences, Lahore, Pakistan
| | - Lisbet Haglund
- Department of Surgery, The Orthopaedic Research Laboratory Montreal General Hospital, McGill University, 1650 Cedar Avenue, Room C10.148.2, Montreal, QC, H3G 1A4, Canada.
| | - Dino Samartzis
- Department of Orthopedic Surgery, Orthopedic Building, Rush University Medical Center, 1611 W. Harrison Street, Chicago, IL, 60612, USA.
- International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, USA.
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Kenawy HM, Marshall SL, Rogot J, Lee AJ, Hung CT, Chahine NO. Blocking toll-like receptor 4 mitigates static loading induced pro-inflammatory expression in intervertebral disc motion segments. J Biomech 2023; 150:111491. [PMID: 36870259 PMCID: PMC10108674 DOI: 10.1016/j.jbiomech.2023.111491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 01/23/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023]
Abstract
While the anabolic effects of mechanical loading on the intervertebral disc (IVD) have been extensively studied, inflammatory responses to loading have not been as well characterized. Recent studies have highlighted a significant role of innate immune activation, particularly that of toll-like receptors (TLRs), in IVD degeneration. Biological responses of intervertebral disc cells to loading depend on many factors that include magnitude and frequency. The goals of this study were to characterize the inflammatory signaling changes in response to static and dynamic loading of IVD and investigate the contributions of TLR4 signaling in response to mechanical loading. Rat bone-disc-bone motion segments were loaded for 3 hr under a static load (20 % strain, 0 Hz) with or without an additional low-dynamic (4 % dynamic strain, 0.5 Hz) or high-dynamic (8 % dynamic strain, 3 Hz) strain, and results were compared to unloaded controls. Some samples were also loaded with or without TAK-242, an inhibitor of TLR4 signaling. The magnitude of NO release into the loading media (LM) was correlated with the applied frequency and strain magnitudes across different loading groups. Injurious loading profiles, such as static and high-dynamic, significantly increased Tlr4 and Hmgb1 expression while this result was not observed in the more physiologically relevant low-dynamic loading group. TAK-242 co-treatment decreased pro-inflammatory expression in static but not dynamic loaded groups, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static compression. Overall, the microenvironment induced by dynamic loading diminished the protective effects of the TAK-242, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static loading injury.
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Affiliation(s)
- Hagar M Kenawy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Samantha L Marshall
- Department of Orthopedic Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | - James Rogot
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Andy J Lee
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Clark T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | - Nadeen O Chahine
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University Irving Medical Center, New York, NY, USA.
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Basatvat S, Bach FC, Barcellona MN, Binch AL, Buckley CT, Bueno B, Chahine NO, Chee A, Creemers LB, Dudli S, Fearing B, Ferguson SJ, Gansau J, Gantenbein B, Gawri R, Glaeser JD, Grad S, Guerrero J, Haglund L, Hernandez PA, Hoyland JA, Huang C, Iatridis JC, Illien‐Junger S, Jing L, Kraus P, Laagland LT, Lang G, Leung V, Li Z, Lufkin T, van Maanen JC, McDonnell EE, Panebianco CJ, Presciutti SM, Rao S, Richardson SM, Romereim S, Schmitz TC, Schol J, Setton L, Sheyn D, Snuggs JW, Sun Y, Tan X, Tryfonidou MA, Vo N, Wang D, Williams B, Williams R, Yoon ST, Le Maitre CL. Harmonization and standardization of nucleus pulposus cell extraction and culture methods. JOR Spine 2023; 6:e1238. [PMID: 36994456 PMCID: PMC10041384 DOI: 10.1002/jsp2.1238] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/30/2022] [Accepted: 12/09/2022] [Indexed: 01/11/2023] Open
Abstract
Background In vitro studies using nucleus pulposus (NP) cells are commonly used to investigate disc cell biology and pathogenesis, or to aid in the development of new therapies. However, lab-to-lab variability jeopardizes the much-needed progress in the field. Here, an international group of spine scientists collaborated to standardize extraction and expansion techniques for NP cells to reduce variability, improve comparability between labs and improve utilization of funding and resources. Methods The most commonly applied methods for NP cell extraction, expansion, and re-differentiation were identified using a questionnaire to research groups worldwide. NP cell extraction methods from rat, rabbit, pig, dog, cow, and human NP tissue were experimentally assessed. Expansion and re-differentiation media and techniques were also investigated. Results Recommended protocols are provided for extraction, expansion, and re-differentiation of NP cells from common species utilized for NP cell culture. Conclusions This international, multilab and multispecies study identified cell extraction methods for greater cell yield and fewer gene expression changes by applying species-specific pronase usage, 60-100 U/ml collagenase for shorter durations. Recommendations for NP cell expansion, passage number, and many factors driving successful cell culture in different species are also addressed to support harmonization, rigor, and cross-lab comparisons on NP cells worldwide.
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Affiliation(s)
| | - Frances C. Bach
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Marcos N. Barcellona
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
| | - Abbie L. Binch
- Biomolecular Sciences Research CentreSheffield Hallam UniversitySheffieldUK
| | - Conor T. Buckley
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
| | - Brian Bueno
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Nadeen O. Chahine
- Departments of Orthopedic Surgery and Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - Ana Chee
- Department of Orthopedic SurgeryRush University Medical CenterChicagoIllinoisUSA
| | - Laura B. Creemers
- Department of OrthopedicsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Stefan Dudli
- Center for Experimental RheumatologyUniversity of ZurichZurichSwitzerland
| | - Bailey Fearing
- Department of Orthopedic SurgeryAtrium Health Musculoskeletal InstituteCharlotteNorth CarolinaUSA
| | | | - Jennifer Gansau
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Benjamin Gantenbein
- Bone & Joint Program, Department for BioMedical Research (DBMR), Medical FacultyUniversity of BernBernSwitzerland
- Department for Orthopedics and Traumatology, Insel University HospitalUniversity of BernBernSwitzerland
| | - Rahul Gawri
- Division of Orthopaedic Surgery, Department of SurgeryMcGill UniversityMontrealCanada
- Regenerative Orthopaedics and Innovation LaboratoryMcGill UniversityMontrealCanada
| | | | | | - Julien Guerrero
- Bone & Joint Program, Department for BioMedical Research (DBMR), Medical FacultyUniversity of BernBernSwitzerland
- Center of Dental Medicine, Oral Biotechnology & BioengineeringUniversity of ZurichZurichSwitzerland
| | - Lisbet Haglund
- Division of Orthopaedic Surgery, Department of SurgeryMcGill UniversityMontrealCanada
| | - Paula A. Hernandez
- Department of Orthopaedic SurgeryUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Judith A. Hoyland
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences CentreThe University of ManchesterManchesterUK
| | - Charles Huang
- Department of Biomedical EngineeringUniversity of MiamiCoral GablesFloridaUSA
| | - James C. Iatridis
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | | | - Liufang Jing
- Department of OrthopaedicsEmory University School of MedicineAtlantaGAUSA
- Department of Biomedical EngineeringWashington University in St. LouisSt. LouisMissouriUSA
| | - Petra Kraus
- Department of OrthopaedicsEmory University School of MedicineAtlantaGAUSA
- Department of BiologyClarkson UniversityPotsdamNew YorkUSA
| | - Lisanne T. Laagland
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Gernot Lang
- Department of Orthopedics and Trauma Surgery, Medical Center, Faculty of MedicineAlbert‐Ludwigs‐University of FreiburgFreiburg im BreisgauGermany
| | - Victor Leung
- Department of Orthopaedics & TraumatologyThe University of Hong KongHong KongSARChina
| | - Zhen Li
- AO Research Institute DavosDavosSwitzerland
| | - Thomas Lufkin
- Department of BiologyClarkson UniversityPotsdamNew YorkUSA
| | - Josette C. van Maanen
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Emily E. McDonnell
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
| | - Chris J. Panebianco
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | | | - Sanjna Rao
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Stephen M. Richardson
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences CentreThe University of ManchesterManchesterUK
| | - Sarah Romereim
- Department of Orthopedic SurgeryAtrium Health Musculoskeletal InstituteCharlotteNorth CarolinaUSA
| | - Tara C. Schmitz
- Orthopaedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | - Jordy Schol
- Department of Orthopedic SurgeryTokai University School of MedicineIseharaJapan
| | - Lori Setton
- Departments of Biomedical Engineering and Orthopedic SurgeryWashington University in St. LouisSt. LouisMissouriUSA
| | | | - Joseph W. Snuggs
- Biomolecular Sciences Research CentreSheffield Hallam UniversitySheffieldUK
| | - Y. Sun
- Department of Orthopaedics & TraumatologyThe University of Hong KongHong KongSARChina
| | - Xiaohong Tan
- Department of Biomedical EngineeringWashington University in St. LouisSt. LouisMissouriUSA
| | - Marianna A. Tryfonidou
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Nam Vo
- Department of Orthopaedic SurgeryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Dong Wang
- Department of Orthopaedic SurgeryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Brandon Williams
- Department of Orthopedic SurgeryRush University Medical CenterChicagoIllinoisUSA
| | - Rebecca Williams
- Biomolecular Sciences Research CentreSheffield Hallam UniversitySheffieldUK
| | - S. Tim Yoon
- Department of OrthopaedicsEmory University School of MedicineAtlantaGAUSA
| | - Christine L. Le Maitre
- Biomolecular Sciences Research CentreSheffield Hallam UniversitySheffieldUK
- Department of Oncology and MetabolismUniversity of SheffieldSheffieldSouth YorkshireUK
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9
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Pellicore MJ, Gangi LR, Murphy LA, Lee AJ, Jacobsen T, Kenawy HM, Shah RP, Chahine NO, Ateshian GA, Hung CT. Toward defining the role of the synovium in mitigating normal articular cartilage wear and tear. J Biomech 2023; 148:111472. [PMID: 36753853 PMCID: PMC10295808 DOI: 10.1016/j.jbiomech.2023.111472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 01/27/2023]
Abstract
Cartilage repair has been studied extensively in the context of injury and disease, but the joint's management of regular sub-injurious damage to cartilage, or 'wear and tear,' which occurs due to normal activity, is poorly understood. We hypothesize that this cartilage maintenance is mediated in part by cells derived from the synovium that migrate to the worn articular surface. Here, we demonstrate in vitro that the early steps required for such a process can occur. First, we show that under physiologic mechanical loads, chondrocyte death occurs in the cartilage superficial zone along with changes to the cartilage surface topography. Second, we show that synoviocytes are released from the synovial lining under physiologic loads and attach to worn cartilage. Third, we show that synoviocytes parachuted onto a simulated or native cartilage surface will modify their behavior. Specifically, we show that synoviocyte interactions with chondrocytes lead to changes in synoviocyte mechanosensitivity, and we demonstrate that cartilage-attached synoviocytes can express COL2A1, a hallmark of the chondrogenic phenotype. Our findings suggest that synoviocyte-mediated repair of cartilage 'wear and tear' as a component of joint homeostasis is feasible and is deserving of future study.
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Affiliation(s)
- Matthew J Pellicore
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Lianna R Gangi
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Lance A Murphy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Andy J Lee
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Timothy Jacobsen
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Hagar M Kenawy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Roshan P Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA
| | - Nadeen O Chahine
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University, New York, NY, USA
| | - Gerard A Ateshian
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA; Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Clark T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University, New York, NY, USA.
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10
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Tang SN, Bonilla AF, Chahine NO, Colbath AC, Easley JT, Grad S, Haglund L, Le Maitre CL, Leung V, McCoy AM, Purmessur D, Tang SY, Zeiter S, Smith LJ. Controversies in spine research: Organ culture versus in vivo models for studies of the intervertebral disc. JOR Spine 2022; 5:e1235. [PMID: 36601369 PMCID: PMC9799089 DOI: 10.1002/jsp2.1235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/30/2022] Open
Abstract
Intervertebral disc degeneration is a common cause of low back pain, the leading cause of disability worldwide. Appropriate preclinical models for intervertebral disc research are essential to achieving a better understanding of underlying pathophysiology and for the development, evaluation, and translation of more effective treatments. To this end, in vivo animal and ex vivo organ culture models are both widely used by spine researchers; however, the relative strengths and weaknesses of these two approaches are a source of ongoing controversy. In this article, members from the Spine and Preclinical Models Sections of the Orthopedic Research Society, including experts in both basic and translational spine research, present contrasting arguments in support of in vivo animal models versus ex vivo organ culture models for studies of the disc, supported by a comprehensive review of the relevant literature. The objective is to provide a deeper understanding of the respective advantages and limitations of these approaches, and advance the field toward a consensus with respect to appropriate model selection and implementation. We conclude that complementary use of several model types and leveraging the unique advantages of each is likely to result in the highest impact research in most instances.
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Affiliation(s)
- Shirley N. Tang
- Department of Biomedical EngineeringThe Ohio State UniversityColumbusOhioUSA
| | - Andres F. Bonilla
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsColoradoUSA
| | - Nadeen O. Chahine
- Departments of Orthopedic Surgery and Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
| | - Aimee C. Colbath
- Department of Clinical Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Jeremiah T. Easley
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsColoradoUSA
| | | | | | | | - Victor Leung
- Department of Orthopaedics and TraumatologyThe University of Hong KongHong KongSARChina
| | - Annette M. McCoy
- Department of Veterinary Clinical MedicineUniversity of IllinoisUrbanaIllinoisUSA
| | - Devina Purmessur
- Department of Biomedical EngineeringThe Ohio State UniversityColumbusOhioUSA
| | - Simon Y. Tang
- Department of Orthopaedic SurgeryWashington University in St LouisSt LouisMissouriUSA
| | | | - Lachlan J. Smith
- Departments of Orthopaedic Surgery and NeurosurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA,Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
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11
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Forrester LA, Fang F, Jacobsen T, Hu Y, Kurtaliaj I, Roye BD, Guo XE, Chahine NO, Thomopoulos S. Transient neonatal shoulder paralysis causes early osteoarthritis in a mouse model. J Orthop Res 2022; 40:1981-1992. [PMID: 34812543 PMCID: PMC9124737 DOI: 10.1002/jor.25225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/08/2021] [Accepted: 11/20/2021] [Indexed: 02/04/2023]
Abstract
Neonatal brachial plexus palsy (NBPP) occurs in approximately 1.5 of every 1,000 live births. The majority of children with NBPP recover function of the shoulder. However, the long-term risk of osteoarthritis (OA) in this population is unknown. The purpose of this study was to investigate the development of OA in a mouse model of transient neonatal shoulder paralysis. Neonatal mice were injected twice per week for 4 weeks with saline in the right supraspinatus muscle (Saline, control) and botulinum toxin A (BtxA, transient paralysis) in the left supraspinatus muscle, and then allowed to recover for 20 or 36 weeks. Control mice received no injections, and all mice were sacrificed at 24 or 40 weeks. BtxA mice exhibited abnormalities in gait compared to controls through 10 weeks of age, but these differences did not persist into adulthood. BtxA shoulders had decreased bone volume (-9%) and abnormal trabecular microstructure compared to controls. Histomorphometry analysis demonstrated that BtxA shoulders had higher murine shoulder arthritis scale scores (+30%), and therefore more shoulder OA compared to controls. Articular cartilage of BtxA shoulders demonstrated stiffening of the tissue. Compared with controls, articular cartilage from BtxA shoulders had 2-fold and 10-fold decreases in Dkk1 and BMP2 expression, respectively, and 3-fold and 14-fold increases in Col10A1 and BGLAP expression, respectively, consistent with established models of OA. In summary, a brief period of paralysis of the neonatal mouse shoulder was sufficient to generate early signs of OA in adult cartilage and bone.
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Affiliation(s)
- Lynn Ann Forrester
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
| | - Fei Fang
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
| | - Timothy Jacobsen
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Yizhong Hu
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Iden Kurtaliaj
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Benjamin D. Roye
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
| | - X. Edward Guo
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Nadeen O. Chahine
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Stavros Thomopoulos
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
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12
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Poon SC, Nellans K, Gorroochurn P, Chahine NO. Race, But Not Gender, Is Associated With Admissions Into Orthopaedic Residency Programs. Clin Orthop Relat Res 2022; 480:1441-1449. [PMID: 33229901 PMCID: PMC9278929 DOI: 10.1097/corr.0000000000001553] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/09/2020] [Indexed: 01/31/2023]
Abstract
BACKGROUND Orthopaedic surgery is one of the most competitive but least diverse surgical specialties, with ever-increasing academic achievements (such as test scores) shown by applicants. Prior research shows that white applicants had higher United States Medical Licensing Exam (USMLE) Step 1 and Step 2 Clinical Knowledge scores as well as higher odds of Alpha Omega Alpha status compared with Black, Hispanic, and other applicant groups. Yet, it still remains unknown whether differences in application metrics by race/ethnicity sufficiently explain the underrepresentation of certain racial or ethnic minority groups in orthopaedic residency programs. QUESTIONS/PURPOSES In this study, we sought to determine (1) the relative weight of academic variables for admission into orthopaedic residency, and (2) whether race and gender are independently associated with admission into an orthopedic residency. METHODS The Electronic Residency Application System (ERAS) data from the Association of American Medical Colleges (AAMC) and the National Board of Medical Examiners (NBME) of first-time MD applicants (n = 8966) for orthopaedic surgery residency positions in the United States and of admitted orthopaedic residents (n = 6218) from 2005 to 2014 were reviewed. This dataset is the first and most comprehensive of its kind to date in orthopaedic surgery. Academic metrics, such as USMLE Step 1 and Step 2 Clinical Knowledge scores, number of publications, Alpha Omega Alpha status, volunteer experiences, work experience, as well as race and gender, were analyzed using hierarchical logistic regression models. The first model analyzed the association of academic metrics with admission into orthopaedic residency. In the second model, we added race and gender and controlled for metrics of academic performance. To determine how well the models simulated the actual admissions data, we computed the receiver operating characteristics (ROC) including the area under curve (AUC), which measures the model's ability to simulate which applicants were admitted or not admitted, with an AUC = 1.0 representing a perfect simulation. The odds ratio and confidence interval of each variable were computed. RESULTS When only academic variables were analyzed in the first model, Alpha Omega Alpha status (odds ratio 2.12 [95% CI 1.80 to 2.50]; p < 0.001), the USMLE Step 1 score (OR 1.04 [95% CI 1.03 to 1.04]; p < 0.001), the USMLE Step 2 Clinical Knowledge score (OR 1.01 [95% CI 1.01 to 1.02]; p < 0.001), publication count (OR 1.04 [95% CI 1.03 to 1.05]; p < 0.001), and volunteer experience (OR 1.03 [95% CI 1.01 to 1.04]; p < 0.001) were associated with admissions into orthopaedics while work and research experience were not. This model yielded a good prediction of the results with an AUC of 0.755. The second model, in which the variables of race and gender were added to the academic variables, also had a good prediction of the results with an AUC of 0.759. This model indicates that applicant race, but not gender, is associated with admissions into orthopaedic residency. Applicants from Asian (OR 0.78 [95% CI 0.67 to 0.92]), Black (OR 0.63 [95% CI 0.51 to 0.77], Hispanic (OR 0.48 [95% CI 0.36 to 0.65]), or other race groups (OR 0.65 [95% CI 0.55 to 0.77]) had lower odds of admission into residency compared with white applicants. CONCLUSION Minority applicants, but not women, have lower odds of admission into orthopaedic surgery residency, even when accounting for academic performance metrics. Changes in the residency selection processes are needed to eliminate the lower admission probability of qualified minority applicants in orthopaedic residency and to improve the diversity and inclusion of orthopaedic surgery. Changes including increasing the diversity of the selection committee, bias training, blinding applications before review, removal of metrics with history of racial disparities from an interviewer's candidate profile before an interview, and use of holistic application review (where an applicants' experiences, attributes, and academic metrics are all considered) can improve the diversity landscape in training. In addition, cultivating an environment of inclusion will be necessary to address these long-standing trends in orthopaedic surgery. CLINICAL RELEVANCE Race, but not gender, is associated with the odds of acceptance into orthopaedic surgery residency despite equivalent academic metrics. Changes in residency selection processes are suggested to eliminate the lower admission probability of qualified minority applicants into orthopaedic residency and to improve the diversity and inclusion of orthopaedic surgery.
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Affiliation(s)
- Selina C Poon
- Orthopaedic Surgery Department, Shriners for Children Medical Center at Pasadena, Pasadena, CA, USA
| | - Kate Nellans
- Department of Orthopaedic Surgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, NY, USA
| | - Prakash Gorroochurn
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Department of Biomedical Engineering, Columbia University, New York, NY, USA
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13
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Marshall SL, Jacobsen TD, Emsbo E, Murali A, Anton K, Liu JZ, Lu HH, Chahine NO. Three-Dimensional-Printed Flexible Scaffolds Have Tunable Biomimetic Mechanical Properties for Intervertebral Disc Tissue Engineering. ACS Biomater Sci Eng 2021; 7:5836-5849. [PMID: 34843224 DOI: 10.1021/acsbiomaterials.1c01326] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The intervertebral disc (IVD) exhibits complex structure and biomechanical function, which supports the weight of the body and permits motion. Surgical treatments for IVD degeneration (e.g., lumbar fusion, disc replacement) often disrupt the mechanical environment of the spine which lead to adjacent segment disease. Alternatively, disc tissue engineering strategies, where cell-seeded hydrogels or fibrous biomaterials are cultured in vitro to promote matrix deposition, do not recapitulate the complex IVD mechanical properties. In this study, we use 3D printing of flexible polylactic acid (FPLA) to fabricate a viscoelastic scaffold with tunable biomimetic mechanics for whole spine motion segment applications. We optimized the mechanical properties of the scaffolds for equilibrium and dynamic moduli in compression and tension by varying fiber spacing or porosity, generating scaffolds with de novo mechanical properties within the physiological range of spine motion segments. The biodegradation analysis of the 3D printed scaffolds showed that FPLA exhibits lower degradation rate and thus has longer mechanical stability than standard PLA. FPLA scaffolds were biocompatible, supporting viability of nucleus pulposus (NP) cells in 2D and in FPLA+hydrogel composites. Composite scaffolds cultured with NP cells maintained baseline physiological mechanical properties and promoted matrix deposition up to 8 weeks in culture. Mesenchymal stromal cells (MSCs) cultured on FPLA adhered to the scaffold and exhibited fibrocartilaginous differentiation. These results demonstrate for the first time that 3D printed FPLA scaffolds have de novo viscoelastic mechanical properties that match the native IVD motion segment in both tension and compression and have the potential to be used as a mechanically stable and biocompatible biomaterial for engineered disc replacement.
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Affiliation(s)
- Samantha L Marshall
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Timothy D Jacobsen
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States.,Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Erik Emsbo
- Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Archana Murali
- Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Kevin Anton
- Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Jessica Z Liu
- Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Helen H Lu
- Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States.,Department of Biomedical Engineering, Columbia University, 650 West 168th Street, 1410, New York, New York 10031, United States
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14
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Coury JR, Nixon R, Collins M, Schwartz J, Chahine NO, Grande DA. Oral Administration of a Chemically Modified Curcumin, TRB-N0224, Reduced Inflammatory Cytokines and Cartilage Erosion in a Rabbit ACL Transection Injury Model. Cartilage 2021; 12:251-262. [PMID: 30486657 PMCID: PMC7970374 DOI: 10.1177/1947603518815263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To evaluate the effects of TRB-N0224, a chemically modified curcumin (CMC) with zinc binding properties and improved pharmacokinetics, in a rabbit anterior cruciate ligament (ACL) transection injury-induced model of osteoarthritis (OA). DESIGN Thirty-eight skeletally mature New Zealand white rabbits were studied in 4 groups: a sham with arthrotomy (n = 6), control with ACL transection (n = 6), and 2 treatment groups with ACL transection and administration of TRB-N0224 at low (25 mg/kg/day) (n = 13) and high (50 mg/kg/day) (n = 13) doses. After euthanization at 12 weeks, outcomes were measured by post-necropsy gross morphology, biomechanics, and cartilage and synovium histology. Rabbit blood ELISA quantified cytokine and matrix metalloproteinase (MMP) concentrations at 0, 4, 8, and 12 weeks. RESULTS Both treatment doses had fewer distal femoral condyle erosive defects than the control; the low dose demonstrated a mean 78% decrease (P < 0.01). Histologically, the low- and high-dose treatment groups had fewer cartilage pathologic changes and less severe synovitis than the control. CMC alone did not have a major effect on the biomechanics of healthy cartilage or cartilage in the ACL transection model, as demonstrated in 5 of the 6 measured properties/regions (P < 0.05). ELISA results suggested that the key mediators of OA, (interleukin) IL-1β, IL-6, TNFα (tumor necrosis factor-α), MMP-9, and MMP-13, had decreased concentrations with TRB-N0224 treatment at different time points between weeks 4 to 12 (P < 0.05). CONCLUSIONS In the pathogenesis of OA, an imbalance exists between catabolic and anabolic mediators. These results suggest the potential of TRB-N0224 to modulate MMP and cytokine levels, slowing the macroscopic and histopathological progression of OA.
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Affiliation(s)
- Josephine R. Coury
- The Feinstein Institute for Medical
Research, Manhasset, NY, USA,Zucker School of Medicine at
Hofstra/Northwell, Hempstead, NY, USA
| | - Ryan Nixon
- The Feinstein Institute for Medical
Research, Manhasset, NY, USA,Department of Orthopaedic Surgery,
Northwell Health, New Hyde Park, NY, USA
| | - Melinda Collins
- The Feinstein Institute for Medical
Research, Manhasset, NY, USA
| | - John Schwartz
- The Feinstein Institute for Medical
Research, Manhasset, NY, USA
| | - Nadeen O. Chahine
- Department of Orthopaedic Surgery and
Biomedical Engineering, Columbia University, New York, NY, USA
| | - Daniel A. Grande
- The Feinstein Institute for Medical
Research, Manhasset, NY, USA,Daniel A. Grande, The Feinstein Institute
for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
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15
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Hernandez PA, Jacobsen TD, Barati Z, Chahine NO. Confocal scanning of intervertebral disc cells in 3D: Inside alginate beads and in native microenvironment. JOR Spine 2020; 3:e1106. [PMID: 33392446 PMCID: PMC7770191 DOI: 10.1002/jsp2.1106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/03/2020] [Accepted: 06/30/2020] [Indexed: 02/05/2023] Open
Abstract
The interaction between cells and their extracellular matrix (ECM) is crucial to maintain both tissue and cellular homeostasis. Indeed, cell phenotype is significantly affected by the 3D microenvironment. Although highly convenient, isolating cells from the intervertebral disc (IVD) and growing them in 2D on plastic or glass substrates, causes them to rapidly lose their phenotype and consequently alter their gene and protein expression. While characterization of cells in their native or simulated 3D environment is preferred, such approaches are complexed by limitations in phenotypic readouts. In the current article, we describe a detailed protocol to study nucleus pulposus cells in 3D-embedded in alginate as a permeable cell-staining reservoir, as well as adaptation for cell staining and imaging in their native ECM. This method allows for detection of phenotypical and cytoskeletal changes in cells within native tissue or 3D alginate beads using confocal microscopy, without the need for histological processing.
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Affiliation(s)
- Paula A. Hernandez
- Department of Orthopaedic SurgeryUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | | | - Zahra Barati
- Department of Orthopaedic SurgeryUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Nadeen O. Chahine
- Department of Biomedical EngineeringColumbia UniversityNew YorkNew YorkUSA
- Department of Orthopedic SurgeryColumbia UniversityNew YorkNew YorkUSA
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16
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Hernandez PA, Jacobsen TD, Chahine NO. Actomyosin contractility confers mechanoprotection against TNFα-induced disruption of the intervertebral disc. Sci Adv 2020; 6:eaba2368. [PMID: 32875103 PMCID: PMC7438088 DOI: 10.1126/sciadv.aba2368] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
Inflammation triggers degradation of intervertebral disc extracellular matrix (ECM), a hallmark of disc degeneration that contributes to back pain. Mechanosensitive nucleus pulposus cells are responsible for ECM production, yet the impact of a proinflammatory microenvironment on cell mechanobiology is unknown. Using gain- and loss-of-function approaches, we show that tumor necrosis factor-α (TNFα)-induced inflammation alters cell morphology and biophysical properties (circularity, contractility, cell stiffness, and hydraulic permeability) in a mechanism dependent on actomyosin contractility in a three-dimensional (3D) culture. We found that RhoA activation rescued cells from TNFα-induced mechanobiological disruption. Using a novel explant-in-hydrogel culture system, we demonstrate that nuclear factor kappa-B nuclear translocation and transcription are mechanosensitive, and its downstream effects on ECM degradation are regulated by actomyosin contractility. Results define a scaling relationship between circularity, contractility, and hydraulic permeability that is conserved from healthy to inflammatory microenvironments and is indicative of cell mechanobiological control across scales in 3D.
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Affiliation(s)
- Paula A. Hernandez
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Timothy D. Jacobsen
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Nadeen O. Chahine
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA
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17
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Wagner EK, Vedadghavami A, Jacobsen TD, Goel SA, Chahine NO, Bajpayee AG. Avidin grafted dextran nanostructure enables a month-long intra-discal retention. Sci Rep 2020; 10:12017. [PMID: 32694557 PMCID: PMC7374582 DOI: 10.1038/s41598-020-68351-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/17/2020] [Indexed: 12/16/2022] Open
Abstract
Low back pain is often the direct result of degeneration of the intervertebral disc. A wide range of therapeutics including anti-catabolic, pro-anabolic factors and chemo-attractants that can stimulate resident cells and recruit endogenous progenitors are under consideration. The avascular nature and the dense matrix of this tissue make it challenging for systemically administered drugs to reach their target cells inside the nucleus pulposus (NP), the central gelatinous region of the intervertebral disc (IVD). Therefore, local intra-discal injection of therapeutic drugs directly into the NP is a clinically relevant delivery approach, however, suffers from rapid and wide diffusion outside the injection site resulting in short lived benefits while causing systemic toxicity. NP has a high negative fixed charge density due to the presence of negatively charged aggrecan glycosaminoglycans that provide swelling pressures, compressive stiffness and hydration to the tissue. This negative fixed charge density can also be used for enhancing intra-NP residence time of therapeutic drugs. Here we design positively charged Avidin grafted branched Dextran nanostructures that utilize long-range binding effects of electrostatic interactions to bind with the intra-NP negatively charged groups. The binding is strong enough to enable a month-long retention of cationic nanostructures within the NP following intra-discal administration, yet weak and reversible to allow movement to reach cells dispersed throughout the tissue. The branched carrier has multiple sites for drug conjugation and can reduce the need for multiple injections of high drug doses and minimize associated side-effects, paving the way for effective clinical translation of potential therapeutics for treatment of low back pain and disc degeneration.
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Affiliation(s)
- Erica K Wagner
- Department of Bioengineering, Northeastern University, 805 Columbus Avenue, Boston, MA, 02120, USA
| | - Armin Vedadghavami
- Department of Bioengineering, Northeastern University, 805 Columbus Avenue, Boston, MA, 02120, USA
| | - Timothy D Jacobsen
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 14-1410, New York, NY, 10032, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Shakti A Goel
- Department of Orthopedic Surgery, Indian Spinal Injuries Center, New Delhi, India
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 14-1410, New York, NY, 10032, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
| | - Ambika G Bajpayee
- Department of Bioengineering, Northeastern University, 805 Columbus Avenue, Boston, MA, 02120, USA.
- Department of Mechanical Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
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18
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Clyne AM, Marcolongo M, Darling EM, Chahine NO. Correction to: Translating Mechanobiology to the Clinic: A Panel Discussion from the 2018 CMBE Conference. Cell Mol Bioeng 2019; 12:131. [PMID: 31719903 DOI: 10.1007/s12195-018-00558-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
[This corrects the article DOI: 10.1007/s12195-018-0556-5.].
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19
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Shah BS, Chahine NO. Dynamic Hydrostatic Pressure Regulates Nucleus Pulposus Phenotypic Expression and Metabolism in a Cell Density-Dependent Manner. J Biomech Eng 2019; 140:2666887. [PMID: 29247254 DOI: 10.1115/1.4038758] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Indexed: 11/08/2022]
Abstract
Dynamic hydrostatic pressure (HP) loading can modulate nucleus pulposus (NP) cell metabolism, extracellular matrix (ECM) composition, and induce transformation of notochordal NP cells into mature phenotype. However, the effects of varying cell density and dynamic HP magnitude on NP phenotype and metabolism are unknown. This study examined the effects of physiological magnitudes of HP loading applied to bovine NP cells encapsulated within three-dimensional (3D) alginate beads. Study 1: seeding density (1 M/mL versus 4 M/mL) was evaluated in unloaded and loaded (0.1 MPa, 0.1 Hz) conditions. Study 2: loading magnitude (0, 0.1, and 0.6 MPa) applied at 0.1 Hz to 1 M/mL for 7 days was evaluated. Study 1: 4 M/mL cell density had significantly lower adenosine triphosphate (ATP), glycosaminoglycan (GAG) and collagen content, and increased lactate dehydrogenase (LDH). HP loading significantly increased ATP levels, and expression of aggrecan, collagen I, keratin-19, and N-cadherin in HP loaded versus unloaded groups. Study 2: aggrecan expression increased in a dose dependent manner with HP magnitude, whereas N-cadherin and keratin-19 expression were greatest in low HP loading compared to unloaded. Overall, the findings of the current study indicate that cell seeding density within a 3D construct is a critical variable influencing the mechanobiological response of NP cells to HP loading. NP mechanobiology and phenotypic expression was also found to be dependent on the magnitude of HP loading. These findings suggest that HP loading and culture conditions of NP cells may require complex optimization for engineering an NP replacement tissue.
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Affiliation(s)
- Bhranti S Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY 10032
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 14-1408E, New York, NY 10032.,Department of Biomedical Engineering, Columbia University, New York, NY 10032 e-mail:
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20
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Poon S, Nellans K, Crabb RAL, Rothman A, Wendolowski SF, Kiridly D, Gecelter R, Akerman M, Chahine NO. Academic Metrics Do Not Explain the Underrepresentation of Women in Orthopaedic Training Programs. J Bone Joint Surg Am 2019; 101:e32. [PMID: 30994596 DOI: 10.2106/jbjs.17.01372] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Among medical specialties, orthopaedic surgery persistently has one of the lowest representations of women in residency programs. This study examined whether differences exist in the academic metrics of the orthopaedic residency applicants and enrolled candidates by sex, which may be contributing to the persistent underrepresentation of women. Differences in enrollment rate in orthopaedic residency programs also were analyzed. We hypothesized that academic metrics were similar for female and male applicants and thus do not explain the underrepresentation of women in training programs. METHODS Academic data of first-time applicants (n = 9,133) and candidates who enrolled in an orthopaedic residency (n = 6,381) in the U.S. from 2005 to 2014 were reviewed. The United States Medical Licensing Examination (USMLE) Step-1 and Step-2 Clinical Knowledge (CK) scores, Alpha Omega Alpha (AΩA) Honor Medical Society status, number of publications, and volunteer experiences were compared by sex and were analyzed over time. RESULTS From 2005 to 2014, representation of female applicants increased from 12.6% to 16.0%, corresponding with an increase in the percentage of enrolled female residents (from 12.9% to 16.1%); 70.3% of male and 67.1% of female applicants to orthopaedic residency enrolled as residents (p = 0.082). Mean academic metrics increased significantly over time for applicants and enrolled candidates, irrespective of sex. Comparing by sex, the mean USMLE Step-1 scores of male applicants and enrolled candidates were approximately 2% higher than those of female applicants (p < 0.0001). Volunteer experiences of female applicants and enrolled candidates were 12% higher compared with male applicants (p < 0.0001). There was no significant difference in USMLE Step-2 CK scores, number of publications, or AΩA status by sex. CONCLUSIONS The enrollment rate of male and female applicants in orthopaedic residencies was similar and did not change during the 10-year study period. The academic metrics of applicants and enrolled candidates have increased significantly. The academic metrics were found to be comparable by sex; the differences in USMLE Step-1 scores and volunteer experiences were small relative to the magnitude of accomplishments that these values represent. The growth rate of the proportion of women in orthopaedic residencies lags other surgical subspecialties but appears to be independent of academic metrics.
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Affiliation(s)
- Selina Poon
- Orthopaedic Surgery, Shriners for Children Medical Center, Pasadena, California
| | - Kate Nellans
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, Northwell Health, New York, NY.,Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, East Garden City, New York
| | - Rocío A L Crabb
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, East Garden City, New York
| | - Alyssa Rothman
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, East Garden City, New York
| | - Stephen F Wendolowski
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, Northwell Health, New York, NY
| | - Daniel Kiridly
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, Northwell Health, New York, NY
| | - Rachel Gecelter
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, Northwell Health, New York, NY
| | - Meredith Akerman
- Biostatistics Unit, Feinstein Institute for Medical Research, Northwell Health, New York, NY
| | - Nadeen O Chahine
- Department of Orthopedic Surgery and Biomedical Engineering, Columbia University, New York, NY
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21
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Stefani RM, Halder SS, Estell EG, Lee AJ, Silverstein AM, Sobczak E, Chahine NO, Ateshian GA, Shah RP, Hung CT. A Functional Tissue-Engineered Synovium Model to Study Osteoarthritis Progression and Treatment. Tissue Eng Part A 2019; 25:538-553. [PMID: 30203722 PMCID: PMC6482911 DOI: 10.1089/ten.tea.2018.0142] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/31/2018] [Indexed: 01/15/2023] Open
Abstract
IMPACT STATEMENT The synovium envelops the diarthrodial joint and plays a key regulatory role in defining the composition of the synovial fluid through filtration and biosynthesis of critical boundary lubricants. Synovium changes often precede cartilage damage in osteoarthritis. We describe a novel in vitro tissue engineered model, validated against native synovium explants, to investigate the structure-function of synovium through quantitative solute transport measures. Synovium was evaluated in the presence of a proinflammatory cytokine, interleukin-1, or the clinically relevant corticosteroid, dexamethasone. We anticipate that a better understanding of synovium transport would support efforts to develop more effective strategies aimed at restoring joint health.
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Affiliation(s)
- Robert M. Stefani
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Saiti S. Halder
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Eben G. Estell
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Andy J. Lee
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Amy M. Silverstein
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Evie Sobczak
- Department of Biomedical Engineering, Columbia University, New York, New York
| | - Nadeen O. Chahine
- Department of Biomedical Engineering, Columbia University, New York, New York
- Department of Orthopedic Surgery, Columbia University, New York, New York
| | - Gerard A. Ateshian
- Department of Biomedical Engineering, Columbia University, New York, New York
- Department of Mechanical Engineering, Columbia University, New York, New York
| | - Roshan P. Shah
- Department of Orthopedic Surgery, Columbia University, New York, New York
| | - Clark T. Hung
- Department of Biomedical Engineering, Columbia University, New York, New York
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22
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Shah BS, Burt KG, Jacobsen T, Fernandes TD, Alipui DO, Weber KT, Levine M, Chavan SS, Yang H, Tracey KJ, Chahine NO. High mobility group box-1 induces pro-inflammatory signaling in human nucleus pulposus cells via toll-like receptor 4-dependent pathway. J Orthop Res 2019; 37:220-231. [PMID: 30273982 PMCID: PMC7401857 DOI: 10.1002/jor.24154] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 09/24/2018] [Indexed: 02/04/2023]
Abstract
Intervertebral disc (IVD) degeneration (DD) is associated with low back pain, the leading cause of disability worldwide. Damage-associated molecular patterns (DAMPs) that contribute to inflammation and trigger DD have not been well characterized. Extracellular high mobility group box-1 (HMGB1) protein has been implicated as a potent DAMP and pro-inflammatory stimulus in the immune system. In this study, we show that HMGB1 and IL-6 levels increase in patients with advanced DD in comparison to early DD. This study further tested the hypothesis that HMGB1 promotes inflammatory signaling driving DD in human nucleus pulposus (NP) cells and tissue. Immunofluorescence and western blot analysis confirmed the expression of HMGB1 and its extracellular release by NP cells under cell stress. Gene expression and protein quantification indicate that HMGB1 stimulates the expression IL-6 and MMP-1 in a dose-dependent manner. The contributions of toll-like receptor (TLR) -2, -4 and receptor for advanced glycation end products (RAGE) as receptors mediating HMGB1 signaling was examined using small molecule inhibitors. Inhibition of TLR-4 signaling, with TAK-242, completely abrogated HMGB1 induced IL-6 and MMP-1 expression, whereas inhibition of TLR-2, with O-vanillin, or RAGE, with FPS-ZM1, had mild inhibitory effects. HMGB1 stimulation activated NF-ĸB signaling while TAK-242 co-treatment abrogated it. Lastly, effects of HMGB1 on matrix deposition was evaluated in a 3D culture system of human NP cells. These results implicate HMGB1 as a potent DAMP that promotes inflammation in NP cells and degradation of NP tissues. TLR4-HMGB1 axis is a potential major pathway to alleviate disc inflammation and mitigate DD. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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Affiliation(s)
- Bhranti S. Shah
- Department of Orthopedic Surgery, Columbia University, New York, New York
| | - Kevin G. Burt
- Department of Orthopedic Surgery, Columbia University, New York, New York,Department of Biomedical Engineering, Columbia University, New York, New York
| | - Timothy Jacobsen
- Department of Orthopedic Surgery, Columbia University, New York, New York,Department of Biomedical Engineering, Columbia University, New York, New York
| | - Tiago D. Fernandes
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York
| | | | - Kathryn T. Weber
- Department of Surgery, Hofstra Northwell School of Medicine, Hempstead, New York
| | - Mitchell Levine
- Department of Neurosurgery, Lenox Hill Hospital, Northwell Health, New York, New York
| | - Sangeeta S. Chavan
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York,Department of Molecular Medicine, Hofstra Northwell School of Medicine, Hempstead, New York
| | - Huan Yang
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York,Department of Molecular Medicine, Hofstra Northwell School of Medicine, Hempstead, New York
| | - Kevin J. Tracey
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York,Department of Molecular Medicine, Hofstra Northwell School of Medicine, Hempstead, New York
| | - Nadeen O. Chahine
- Department of Orthopedic Surgery, Columbia University, New York, New York,Department of Biomedical Engineering, Columbia University, New York, New York
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23
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Abstract
Mechanical loading of the intervertebral disc (IVD) initiates cell-mediated remodeling events that contribute to disc degeneration. Cells of the IVD, nucleus pulposus (NP) and anulus fibrosus (AF), will exhibit various responses to different mechanical stimuli which appear to be highly dependent on loading type, magnitude, duration, and anatomic zone of cell origin. Cells of the NP, the innermost region of the disc, exhibit an anabolic response to low-moderate magnitudes of static compression, osmotic pressure, or hydrostatic pressure, while higher magnitudes promote a catabolic response marked by increased protease expression and activity. Cells of the outer AF are responsive to physical forces in a manner that depends on frequency and magnitude, as are cells of the NP, though they experience different forces, deformations, pressure, and osmotic pressure in vivo. Much remains to be understood of the mechanotransduction pathways that regulate IVD cell responses to loading, including responses to specific stimuli and also differences among cell types. There is evidence that cytoskeletal remodeling and receptor-mediated signaling are important mechanotransduction events that can regulate downstream effects like gene expression and posttranslational biosynthesis, all of which may influence phenotype and bioactivity. These and other mechanotransduction events will be regulated by known and to-be-discovered cell-matrix and cell-cell interactions, and depend on composition of extracellular matrix ligands for cell interaction, matrix stiffness, and the phenotype of the cells themselves. Here, we present a review of the current knowledge of the role of mechanical stimuli and the impact upon the cellular response to loading and changes that occur with aging and degeneration of the IVD.
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Affiliation(s)
- Bailey V Fearing
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Paula A Hernandez
- Department of Orthopaedic Surgery, University of Texas Southwestern, Dallas, Texas
| | - Lori A Setton
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Nadeen O Chahine
- Department of Orthopedic Surgery & Biomedical Engineering, Columbia University, New York, New York
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24
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Khan AN, Jacobsen HE, Khan J, Filippi CG, Levine M, Lehman RA, Riew KD, Lenke LG, Chahine NO. Inflammatory biomarkers of low back pain and disc degeneration: a review. Ann N Y Acad Sci 2018; 1410:68-84. [PMID: 29265416 DOI: 10.1111/nyas.13551] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/12/2017] [Accepted: 10/18/2017] [Indexed: 12/16/2022]
Abstract
Biomarkers are biological characteristics that can be used to indicate health or disease. This paper reviews studies on biomarkers of low back pain (LBP) in human subjects. LBP is the leading cause of disability, caused by various spine-related disorders, including intervertebral disc degeneration, disc herniation, spinal stenosis, and facet arthritis. The focus of these studies is inflammatory mediators, because inflammation contributes to the pathogenesis of disc degeneration and associated pain mechanisms. Increasingly, studies suggest that the presence of inflammatory mediators can be measured systemically in the blood. These biomarkers may serve as novel tools for directing patient care. Currently, patient response to treatment is unpredictable with a significant rate of recurrence, and, while surgical treatments may provide anatomical correction and pain relief, they are invasive and costly. The review covers studies performed on populations with specific diagnoses and undefined origins of LBP. Since the natural history of LBP is progressive, the temporal nature of studies is categorized by duration of symptomology/disease. Related studies on changes in biomarkers with treatment are also reviewed. Ultimately, diagnostic biomarkers of LBP and spinal degeneration have the potential to shepherd an era of individualized spine medicine for personalized therapeutics in the treatment of LBP.
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Affiliation(s)
- Aysha N Khan
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York
| | - Hayley E Jacobsen
- Department of Orthopedic Surgery, Columbia University, New York, New York
| | - Jansher Khan
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York
| | | | | | - Ronald A Lehman
- Department of Orthopedic Surgery, Columbia University, New York, New York.,New York-Presbyterian-Spine Hospital, New York, New York
| | - K Daniel Riew
- Department of Orthopedic Surgery, Columbia University, New York, New York.,New York-Presbyterian-Spine Hospital, New York, New York
| | - Lawrence G Lenke
- Department of Orthopedic Surgery, Columbia University, New York, New York.,New York-Presbyterian-Spine Hospital, New York, New York
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, New York, New York.,Department of Biomedical Engineering, Columbia University, New York, New York
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25
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Asnis S, Mullen J, Asnis PD, Sgaglione N, LaPorta T, Grande DA, Chahine NO. Biomechanical analysis of an interference screw and a novel twist lock screw design for bone graft fixation. Clin Biomech (Bristol, Avon) 2017; 50:99-104. [PMID: 29055245 DOI: 10.1016/j.clinbiomech.2017.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 10/03/2017] [Accepted: 10/06/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Malpositioning of an anterior cruciate ligament graft during reconstruction can occur during screw fixation. The purpose of this study is to compare the fixation biomechanics of a conventional interference screw with a novel Twist Lock Screw, a rectangular shaped locking screw that is designed to address limitations of graft positioning and tensioning. METHODS Synthetic bone (10, 15, 20lb per cubic foot) were used simulating soft, moderate, and dense cancellous bone. Screw push-out and graft push-out tests were performed using conventional and twist lock screws. Maximum load and torque of insertion were measured. FINDINGS Max load measured in screw push out with twist lock screw was 64%, 60%, 57% of that measured with conventional screw in soft, moderate and dense material, respectively. Twist lock max load was 78% and 82% of that with conventional screw in soft and moderate densities. In the highest bone density, max loads were comparable in the two systems. Torque of insertion with twist lock was significantly lower than with conventional interference screw. INTERPRETATION Based on geometric consideration, the twist lock screw is expected to have 35% the holding power of a cylindrical screw. Yet, results indicate that holding power was greater than theoretical consideration, possibly due to lower friction and lower preloaded force. During graft push out in the densest material, comparable max loads were achieved with both systems, suggesting that fixation of higher density bone, which is observed in young athletes that require reconstruction, can be achieved with the twist lock screw.
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Affiliation(s)
- S Asnis
- Department of Orthopaedic Surgery, LIJ Medical Center, Northwell Health, New Hyde Park, NY, USA; Department of Orthopaedic Surgery, Hofstra Northwell School of Medicine, Hempstead, NY, USA.
| | - J Mullen
- Department of Orthopaedic Surgery, LIJ Medical Center, Northwell Health, New Hyde Park, NY, USA
| | - P D Asnis
- Division of Sports Orthopaedic Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA, USA
| | - N Sgaglione
- Department of Orthopaedic Surgery, LIJ Medical Center, Northwell Health, New Hyde Park, NY, USA; Department of Orthopaedic Surgery, Hofstra Northwell School of Medicine, Hempstead, NY, USA
| | - T LaPorta
- Department of Orthopaedic Surgery, LIJ Medical Center, Northwell Health, New Hyde Park, NY, USA
| | - D A Grande
- Department of Orthopaedic Surgery, LIJ Medical Center, Northwell Health, New Hyde Park, NY, USA; Department of Orthopaedic Surgery, Hofstra Northwell School of Medicine, Hempstead, NY, USA; Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY, USA
| | - N O Chahine
- Department of Orthopedic Surgery and Biomedical Engineering, Columbia University, New York, NY, USA
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26
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Nguyen QT, Norelli JB, Graver A, Ekstein C, Schwartz J, Chowdhury F, Drakos MC, Grande DA, Chahine NO. Therapeutic Effects of Doxycycline on the Quality of Repaired and Unrepaired Achilles Tendons. Am J Sports Med 2017; 45:2872-2881. [PMID: 28759732 DOI: 10.1177/0363546517716637] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Achilles tendon tears are devastating injuries, especially to athletes. Elevated matrix metalloproteinase (MMP) activity after a tendon injury has been associated with deterioration of the collagen network and can be inhibited with doxycycline (Doxy). HYPOTHESIS Daily oral administration of Doxy will enhance the histological, molecular, and biomechanical quality of transected Achilles tendons. Additionally, suture repair will further enhance the quality of repaired tendons. STUDY DESIGN Controlled laboratory study. METHODS Randomized unilateral Achilles tendon transection was performed in 288 adult male Sprague-Dawley rats. The injured tendons were either unrepaired (groups 1 and 2) or surgically repaired (groups 3 and 4). Animals from groups 2 and 4 received Doxy daily through oral gavage, and animals from groups 1 and 3 served as controls (no Doxy). Tendons were harvested at 1.5, 3, 6, and 9 weeks after the injury (n = 18 per group and time point). The quality of tendon repair was evaluated based on the histological grading score, collagen fiber orientation, gene expression, and biomechanical properties. RESULTS In surgically repaired samples, Doxy enhanced the quality of tendon repair compared with no Doxy ( P = .0014). Doxy had a significant effect on collagen fiber dispersion, but not principal fiber angle. There was a significant effect of time on the gene expression of MMP-3, MMP-9 and TIMP1, and Doxy significantly decreased MMP-3 expression at 9 weeks. Doxy treatment with surgical repair increased the dynamic modulus at 6 weeks but not at 9 weeks after the injury ( P < .001). Doxy also increased the equilibrium modulus and decreased creep strain irrespective of the repair group. Doxy did not have a significant effect on the histology or biomechanics of unrepaired tendons. CONCLUSION The findings indicate that daily oral administration of Doxy accelerated matrix remodeling and the dynamic and equilibrium biomechanics of surgically repaired Achilles tendons, although such enhancements were most evident at the 3- to 6-week time points. CLINICAL RELEVANCE The inhibition of MMPs at the optimal stage of the repair process may accelerate Achilles tendon repair and improve biomechanical properties, especially when paired with surgical management.
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Affiliation(s)
- Quynhhoa T Nguyen
- Bioengineering-Biomechanics Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
| | - Jolanta B Norelli
- Orthopaedic Research Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA.,Hofstra Northwell School of Medicine, Hofstra University, Hempstead, New York, USA
| | - Adam Graver
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, New Hyde Park, New York, USA
| | - Charles Ekstein
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, New Hyde Park, New York, USA
| | - Johnathan Schwartz
- Orthopaedic Research Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
| | - Farzana Chowdhury
- Bioengineering-Biomechanics Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
| | - Mark C Drakos
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, New Hyde Park, New York, USA.,Hospital for Special Surgery, New York, New York, USA
| | - Daniel A Grande
- Orthopaedic Research Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA.,Hofstra Northwell School of Medicine, Hofstra University, Hempstead, New York, USA.,Department of Orthopaedic Surgery, Long Island Jewish Medical Center, New Hyde Park, New York, USA
| | - Nadeen O Chahine
- Bioengineering-Biomechanics Laboratory, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA.,Hofstra Northwell School of Medicine, Hofstra University, Hempstead, New York, USA
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27
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Nguyen QT, Jacobsen TD, Chahine NO. Effects of Inflammation on Multiscale Biomechanical Properties of Cartilaginous Cells and Tissues. ACS Biomater Sci Eng 2017; 3:2644-2656. [PMID: 29152560 PMCID: PMC5686563 DOI: 10.1021/acsbiomaterials.6b00671] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/24/2017] [Indexed: 12/20/2022]
Abstract
![]()
Cells
within cartilaginous tissues are mechanosensitive and thus
require mechanical loading for regulation of tissue homeostasis and
metabolism. Mechanical loading plays critical roles in cell differentiation,
proliferation, biosynthesis, and homeostasis. Inflammation is an important
event occurring during multiple processes, such as aging, injury,
and disease. Inflammation has significant effects on biological processes
as well as mechanical function of cells and tissues. These effects
are highly dependent on cell/tissue type, timing, and magnitude. In
this review, we summarize key findings pertaining to effects of inflammation
on multiscale mechanical properties at subcellular, cellular, and
tissue level in cartilaginous tissues, including alterations in mechanotransduction
and mechanosensitivity. The emphasis is on articular cartilage and
the intervertebral disc, which are impacted by inflammatory insults
during degenerative conditions such as osteoarthritis, joint pain,
and back pain. To recapitulate the pro-inflammatory cascades that
occur in vivo, different inflammatory stimuli have been used for in
vitro and in situ studies, including tumor necrosis factor (TNF),
various interleukins (IL), and lipopolysaccharide (LPS). Therefore,
this review will focus on the effects of these stimuli because they
are the best studied pro-inflammatory cytokines in cartilaginous tissues.
Understanding the current state of the field of inflammation and cell/tissue
biomechanics may potentially identify future directions for novel
and translational therapeutics with multiscale biomechanical considerations.
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Affiliation(s)
- Q T Nguyen
- Bioengineering-Biomechanics Laboratory The Feinstein Institute for Medical Research, Northwell Health System, Manhasset, New York 11030, United States
| | - T D Jacobsen
- Bioengineering-Biomechanics Laboratory The Feinstein Institute for Medical Research, Northwell Health System, Manhasset, New York 11030, United States.,Hofstra Northwell School of Medicine, Hempstead, New York 11549, United States
| | - N O Chahine
- Bioengineering-Biomechanics Laboratory The Feinstein Institute for Medical Research, Northwell Health System, Manhasset, New York 11030, United States.,Hofstra Northwell School of Medicine, Hempstead, New York 11549, United States
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28
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Maidhof R, Rafiuddin A, Chowdhury F, Jacobsen T, Chahine NO. Timing of mesenchymal stem cell delivery impacts the fate and therapeutic potential in intervertebral disc repair. J Orthop Res 2017; 35:32-40. [PMID: 27334230 DOI: 10.1002/jor.23350] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/21/2016] [Indexed: 02/04/2023]
Abstract
Cell-based therapies offer a promising approach to treat intervertebral disc (IVD) degeneration. The impact of the injury microenvironment on treatment efficacy has not been established. This study used a rat disc stab injury model with administration of mesenchymal stromal cells (MSCs) at 3, 14, or 30 days post injury (DPI) to evaluate the impact of interventional timing on IVD biochemistry and biomechanics. We also evaluated cellular localization within the disc with near infrared imaging to track the time and spatial profile of cellular migration after in vivo delivery. Results showed that upon injection into a healthy disc, MSCs began to gradually migrate outwards over the course of 14 days, as indicated by decreased signal intensity from the disc space and increased signal within the adjacent vertebrae. Cells administered 14 or 30 DPI also tended to migrate out 14 days after injection but cells injected 3 DPI were retained at a significantly higher amount versus the other groups (p < 0.05). Correspondingly the 3 DPI group, but not 14 or 30 DPI groups, had a higher GAG content in the MSC injected discs (p = 0.06). Enrichment of MSCs and increased GAG content in 3 DPI group did not lead to increased compressive biomechanical properties. Findings suggest that cell therapies administered at an early stage of injury/disease progression may have greater chances of mitigating matrix loss, possibly through promotion of MSC activity by the inflammatory microenvironment associated with injury. Future studies will evaluate the mode and driving factors that regulate cellular migration out of the disc. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:32-40, 2017.
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Affiliation(s)
- Robert Maidhof
- Biomechanics and Bioengineering Research Lab, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, New York, 11030
| | - Asfi Rafiuddin
- Biomechanics and Bioengineering Research Lab, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, New York, 11030
| | - Farzana Chowdhury
- Biomechanics and Bioengineering Research Lab, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, New York, 11030
| | - Timothy Jacobsen
- Biomechanics and Bioengineering Research Lab, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, New York, 11030
| | - Nadeen O Chahine
- Biomechanics and Bioengineering Research Lab, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, New York, 11030.,Departments of Molecular Medicine, Neurosurgery, and Orthopedic Surgery, Hofstra Northwell School of Medicine, Hempstead, New York
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Weber KT, Alipui DO, Sison CP, Bloom O, Quraishi S, Overby MC, Levine M, Chahine NO. Serum levels of the proinflammatory cytokine interleukin-6 vary based on diagnoses in individuals with lumbar intervertebral disc diseases. Arthritis Res Ther 2016; 18:3. [PMID: 26743937 PMCID: PMC4718017 DOI: 10.1186/s13075-015-0887-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/03/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Many intervertebral disc diseases cause low back pain (LBP). Proinflammatory cytokines and matrix metalloproteinases (MMPs) participate in disc pathology. In this study, we examined levels of serum cytokines and MMPs in human subjects with diagnoses of disc herniation (DH), spinal stenosis (SS), or degenerative disc disease (DDD) relative to levels in control subjects. Comparison between subjects with DH and those with other diagnoses (Other Dx, grouped from SS and DDD) was performed to elaborate a pathological mechanism based on circulating cytokine levels. METHODS Study participants were recruited from a spine neurosurgery practice (n = 80), a back pain management practice (n = 27), or a control cohort (n = 26). Serum samples were collected before treatment and were assayed by multiplex assays for levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ, tumor necrosis factor-α, MMP-1, MMP-3, and MMP-9. Inflammatory and degradative mediator levels were compared for subjects with LBP and control subjects, by diagnosis and by treatment groups, controlling for effects of sex, age, and reported history of osteoarthritis. Spearman's correlation coefficient was used to examine relationships with age, body mass index (BMI), symptom duration, and smoking history. RESULTS Serum levels of IL-6 were significantly higher in subjects with LBP compared with control subjects. Participants with LBP due to Other Dx had significantly higher levels of IL-6 than DH and controls. Serum levels of MMP-1 were significantly lower in LBP subjects, specifically those with DH, than in control subjects. Positive correlations were found between IL-6 levels and BMI, symptom duration, and age. MMP-1 levels were positively correlated with age. CONCLUSIONS The findings of the present clinical study are the results of the first examination of circulating cytokine levels in DDD and SS and provide evidence for a more extensive role of IL-6 in disc diseases, where patients with DDD or SS have higher serum cytokine levels than those with DH or control subjects. These findings suggest that LBP subjects have low-grade systemic inflammation, and biochemical profiling of circulating cytokines may assist in refining personalized diagnoses of disc diseases.
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Affiliation(s)
- Kathryn T Weber
- The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, NY, USA.
| | - D Olivier Alipui
- The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, NY, USA.
| | - Cristina P Sison
- The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, NY, USA. .,Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA. .,Department of Population Health, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
| | - Ona Bloom
- The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, NY, USA. .,Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA. .,Department of Physical Medicine and Rehabilitation, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
| | - Shaheda Quraishi
- Department of Physical Medicine and Rehabilitation, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA. .,Department of Neurosurgery, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
| | - M Chris Overby
- Department of Neurosurgery, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
| | - Mitchell Levine
- Department of Neurosurgery, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
| | - Nadeen O Chahine
- The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, NY, USA. .,Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA. .,Department of Neurosurgery, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA. .,Department of Orthopedic Surgery, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA.
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Weber KT, Satoh S, Alipui DO, Virojanapa J, Levine M, Sison C, Quraishi S, Bloom O, Chahine NO. Exploratory study for identifying systemic biomarkers that correlate with pain response in patients with intervertebral disc disorders. Immunol Res 2015; 63:170-80. [PMID: 26440592 PMCID: PMC4689741 DOI: 10.1007/s12026-015-8709-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Molecular events that drive disc damage and low back pain (LBP) may precede clinical manifestation of disease onset and can cause detrimental long-term effects such as disability. Biomarkers serve as objective molecular indicators of pathological processes. The goal of this study is to identify systemic biochemical factors as predictors of response to treatment of LBP with epidural steroid injection (ESI). Since inflammation plays a pivotal role in LBP, this pilot study investigates the effect of ESI on systemic levels of 48 inflammatory biochemical factors (cytokines, chemokines, and growth factors) and examines the relationship between biochemical factor levels and pain or disability in patients with disc herniation (DH), or other diagnoses (Other Dx) leading to low back pain, which included spinal stenosis (SS) and degenerative disc disease (DDD). Study participants (n = 16) were recruited from a back pain management practice. Pain numerical rating score (NRS), Oswestry Disability Index (ODI), and blood samples were collected pre- and at 7 to 10 days post-treatment. Blood samples were assayed for inflammatory mediators using commercial multiplex assays. Mediator levels were compared pre- and post-treatment to investigate the potential correlations between clinical and biochemical outcomes. Our results indicate that a single ESI significantly decreased systemic levels of SCGF-β and IL-2. Improvement in pain in all subjects was correlated with changes in chemokines (MCP-1, MIG), hematopoietic progenitor factors (SCGF-β), and factors that participate in angiogenesis/fibrosis (HGF), nociception (SCF, IFN-α2), and inflammation (IL-6, IL-10, IL-18, TRAIL). Levels of biochemical mediators varied based on diagnosis of LBP, and changes in pain responses and systemic mediators from pre- to post-treatment were dependent on the diagnosis cohort. In the DH cohort, levels of IL-17 and VEGF significantly decreased post-treatment. In the Other Dx cohort, levels of IL-2Rα, IL-3, and SCGF-β significantly decreased post-treatment. In order to determine whether mediator changes were related to pain, correlations between change in pain scores and change in mediator levels were performed. Subjects with DH demonstrated a profile signature that implicated hematopoiesis factors (SCGF-β, GM-CSF) in pain response, while subjects with Other Dx demonstrated a biomarker profile that implicated chemokines (MCP-1, MIG) and angiogenic factors (HGF, VEGF) in pain response. Our findings provide evidence that systemic biochemical factors in patients with LBP vary by diagnosis, and pain response to treatment is associated with a unique profile of biochemical responses in each diagnosis group. Future hypothesis-based studies with larger subject cohorts are warranted to confirm the findings of this pilot exploratory study.
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Affiliation(s)
- K T Weber
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Shina Satoh
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA
| | - D Olivier Alipui
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Justin Virojanapa
- Department of Neurosurgery, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
| | - Mitchell Levine
- Department of Neurosurgery, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
| | - Cristina Sison
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA
- Department of Molecular Medicine, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
| | - Shaheda Quraishi
- Department of Neurosurgery, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
- Department of Physical Medicine and Rehabilitation, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
| | - Ona Bloom
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA
- Department of Physical Medicine and Rehabilitation, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
- Department of Molecular Medicine, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA
| | - Nadeen O Chahine
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY, 11030, USA.
- Department of Neurosurgery, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA.
- Department of Molecular Medicine, Hofstra North Shore LIJ School of Medicine, Hempstead, NY, USA.
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Maidhof R, Jacobsen T, Papatheodorou A, Chahine NO. Inflammation induces irreversible biophysical changes in isolated nucleus pulposus cells. PLoS One 2014; 9:e99621. [PMID: 24936787 PMCID: PMC4061011 DOI: 10.1371/journal.pone.0099621] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 05/16/2014] [Indexed: 11/20/2022] Open
Abstract
Intervertebral disc degeneration is accompanied by elevated levels of inflammatory cytokines that have been implicated in disease etiology and matrix degradation. While the effects of inflammatory stimulation on disc cell metabolism have been well-studied, their effects on cell biophysical properties have not been investigated. The hypothesis of this study is that inflammatory stimulation alters the biomechanical properties of isolated disc cells and volume responses to step osmotic loading. Cells from the nucleus pulposus (NP) of bovine discs were isolated and treated with either lipopolysaccharide (LPS), an inflammatory ligand, or with the recombinant cytokine TNF-α for 24 hours. We measured cellular volume regulation responses to osmotic loading either immediately after stimulation or after a 1 week recovery period from the inflammatory stimuli. Cells from each group were tested under step osmotic loading and the transient volume-response was captured via time-lapse microscopy. Volume-responses were analyzed using mixture theory framework to investigate two biomechanical properties of the cell, the intracellular water content and the hydraulic permeability. Intracellular water content did not vary between treatment groups, but hydraulic permeability increased significantly with inflammatory treatment. In the 1 week recovery group, hydraulic permeability remained elevated relative to the untreated recovery control. Cell radius was also significantly increased both after 24 hours of treatment and after 1 week recovery. A significant linear correlation was observed between hydraulic permeability and cell radius in untreated cells at 24 hours and at 1-week recovery, though not in the inflammatory stimulated groups at either time point. This loss of correlation between cell size and hydraulic permeability suggests that regulation of volume change is disrupted irreversibly due to inflammatory stimulation. Inflammatory treated cells exhibited altered F-actin cytoskeleton expression relative to untreated cells. We also found a significant decrease in the expression of aquaporin-1, the predominant water channel in disc NP cells, with inflammatory stimulation. To our knowledge, this is the first study providing evidence that inflammatory stimulation directly alters the mechanobiology of NP cells. The cellular biophysical changes observed in this study are coincident with documented changes in the extracellular matrix induced by inflammation, and may be important in disease etiology.
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Affiliation(s)
- Robert Maidhof
- Center for Autoimmune and Musculoskeletal Diseases, The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, United States of America
| | - Timothy Jacobsen
- Center for Autoimmune and Musculoskeletal Diseases, The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, United States of America
| | - Angelos Papatheodorou
- Center for Autoimmune and Musculoskeletal Diseases, The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, United States of America
| | - Nadeen O. Chahine
- Center for Autoimmune and Musculoskeletal Diseases, The Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, United States of America
- Hofstra-North Shore LIJ School of Medicine, Hempstead, New York, United States of America
- * E-mail:
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Chahine NO, Collette NM, Thomas CB, Genetos DC, Loots GG. Nanocomposite scaffold for chondrocyte growth and cartilage tissue engineering: effects of carbon nanotube surface functionalization. Tissue Eng Part A 2014; 20:2305-15. [PMID: 24593020 DOI: 10.1089/ten.tea.2013.0328] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The goal of this study was to assess the long-term biocompatibility of single-wall carbon nanotubes (SWNTs) for tissue engineering of articular cartilage. We hypothesized that SWNT nanocomposite scaffolds in cartilage tissue engineering can provide an improved molecular-sized substrate for stimulation of chondrocyte growth, as well as structural reinforcement of the scaffold's mechanical properties. The effect of SWNT surface functionalization (-COOH or -PEG) on chondrocyte viability and biochemical matrix deposition was examined in two-dimensional cultures, in three-dimensional (3D) pellet cultures, and in a 3D nanocomposite scaffold consisting of hydrogels+SWNTs. Outcome measures included cell viability, histological and SEM evaluation, GAG biochemical content, compressive and tensile biomechanical properties, and gene expression quantification, including extracellular matrix (ECM) markers aggrecan (Agc), collagen-1 (Col1a1), collagen-2 (Col2a1), collagen-10 (Col10a1), surface adhesion proteins fibronectin (Fn), CD44 antigen (CD44), and tumor marker (Tp53). Our findings indicate that chondrocytes tolerate functionalized SWNTs well, with minimal toxicity of cells in 3D culture systems (pellet and nanocomposite constructs). Both SWNT-PEG and SWNT-COOH groups increased the GAG content in nanocomposites relative to control. The compressive biomechanical properties of cell-laden SWNT-COOH nanocomposites were significantly elevated relative to control. Increases in the tensile modulus and ultimate stress were observed, indicative of a tensile reinforcement of the nanocomposite scaffolds. Surface coating of SWNTs with -COOH also resulted in increased Col2a1 and Fn gene expression throughout the culture in nanocomposite constructs, indicative of increased chondrocyte metabolic activity. In contrast, surface coating of SWNTs with a neutral -PEG moiety had no significant effect on Col2a1 or Fn gene expression, suggesting that the charged nature of the -COOH surface functionalization may promote ECM expression in this culture system. The results of this study indicate that SWNTs exhibit a unique potential for cartilage tissue engineering, where functionalization with bioactive molecules may provide an improved substrate for stimulation of cellular growth and repair.
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Affiliation(s)
- Nadeen O Chahine
- 1 Center for Autoimmune and Musculoskeletal Disease, The Feinstein Institute for Medical Research , Manhasset, New York
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Kessler MW, Barr J, Greenwald R, Lane LB, Dines JS, Dines DM, Drakos MC, Grande DA, Chahine NO. Enhancement of Achilles tendon repair mediated by matrix metalloproteinase inhibition via systemic administration of doxycycline. J Orthop Res 2014; 32:500-6. [PMID: 24346815 DOI: 10.1002/jor.22564] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 11/19/2013] [Indexed: 02/04/2023]
Abstract
Collagenases or matrix metalloproteinases (MMPs) have been shown to play an important role in the matrix degradation cascade associated with Achilles tendon rupture and disease. The goal of this study was to examine the effects of daily administration of doxycycline (Doxy) through oral gavage on MMP activity and on the repair quality of Achilles tendons in vivo. Our findings indicate that Achilles tendon transection resulted in increasing MMP-8 activity from 2 to 6 weeks post-injury, with peak increases in activity occurring at 4 weeks post-injury. Doxy adiministration at clinically relevant serum concentrations was found to significantly inhibit MMP activity after continuous treatment for 4 weeks, but not for continuous administration for shorter durations (96 h or 2 weeks). Extended doxy administration was also associated with improved collagen fibril organization, and enhanced biomechanical properties (stiffness, ultimate tensile strength, maximum load to failure, and elastic toughness). Our findings indicate that a temporal delay exists between Achilles tendon transection and associated increases in MMP-8 activity in situ. Our findings suggest that inhibition of MMP-8 at its peak activity levels ameliorates fibrosis development and improves biomechanical properties of the Achilles tendon.
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Affiliation(s)
- Michael W Kessler
- Orthopaedic Research Lab, The Feinstein Institute for Medical Research, Manhasset, New York; Georgetown University Hospital, Washington, District of Columbia
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Abstract
This review traces the genealogy of the field of articular cartilage repair from its earliest attempts to its present day vast proliferation of research advances. Prior to the 1980s there was only sporadic efforts to regenerate articular cartilage as it was considered to be incapable of regeneration based on historical dogma. The first flurry of reports documented the use of various cell types ultimately leading to the first successful demonstration of autologous chondrocyte transplantation which was later translated to clinical use and has resulted in the revised axiom that cartilage regeneration is possible. The current field of cartilage repair is multifaceted and some of the 1980s' vintage concepts have been revisited with state of the art technology now available. The future of the field is now poised to undertake the repair of whole cartilage surfaces beyond focal defects and an appreciation for integrated whole joint health to restore cartilage homeostasis.
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Affiliation(s)
- Daniel A. Grande
- Department of Orthopaedic Surgery, Feinstein Institute for Medical Research, North Shore–LIJ Health Systems, Manhasset, NY, USA
| | - John A. Schwartz
- Department of Orthopaedic Surgery, Feinstein Institute for Medical Research, North Shore–LIJ Health Systems, Manhasset, NY, USA
| | - Eric Brandel
- Department of Orthopaedic Surgery, Feinstein Institute for Medical Research, North Shore–LIJ Health Systems, Manhasset, NY, USA
| | - Nadeen O. Chahine
- Department of Orthopaedic Surgery, Feinstein Institute for Medical Research, North Shore–LIJ Health Systems, Manhasset, NY, USA
| | - Nicholas Sgaglione
- Department of Orthopaedic Surgery, Feinstein Institute for Medical Research, North Shore–LIJ Health Systems, Manhasset, NY, USA
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Chahine NO, Blanchette C, Thomas CB, Lu J, Haudenschild D, Loots GG. Effect of age and cytoskeletal elements on the indentation-dependent mechanical properties of chondrocytes. PLoS One 2013; 8:e61651. [PMID: 23613892 PMCID: PMC3628340 DOI: 10.1371/journal.pone.0061651] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 03/12/2013] [Indexed: 11/18/2022] Open
Abstract
Articular cartilage chondrocytes are responsible for the synthesis, maintenance, and turnover of the extracellular matrix, metabolic processes that contribute to the mechanical properties of these cells. Here, we systematically evaluated the effect of age and cytoskeletal disruptors on the mechanical properties of chondrocytes as a function of deformation. We quantified the indentation-dependent mechanical properties of chondrocytes isolated from neonatal (1-day), adult (5-year) and geriatric (12-year) bovine knees using atomic force microscopy (AFM). We also measured the contribution of the actin and intermediate filaments to the indentation-dependent mechanical properties of chondrocytes. By integrating AFM with confocal fluorescent microscopy, we monitored cytoskeletal and biomechanical deformation in transgenic cells (GFP-vimentin and mCherry-actin) under compression. We found that the elastic modulus of chondrocytes in all age groups decreased with increased indentation (15-2000 nm). The elastic modulus of adult chondrocytes was significantly greater than neonatal cells at indentations greater than 500 nm. Viscoelastic moduli (instantaneous and equilibrium) were comparable in all age groups examined; however, the intrinsic viscosity was lower in geriatric chondrocytes than neonatal. Disrupting the actin or the intermediate filament structures altered the mechanical properties of chondrocytes by decreasing the elastic modulus and viscoelastic properties, resulting in a dramatic loss of indentation-dependent response with treatment. Actin and vimentin cytoskeletal structures were monitored using confocal fluorescent microscopy in transgenic cells treated with disruptors, and both treatments had a profound disruptive effect on the actin filaments. Here we show that disrupting the structure of intermediate filaments indirectly altered the configuration of the actin cytoskeleton. These findings underscore the importance of the cytoskeletal elements in the overall mechanical response of chondrocytes, indicating that intermediate filament integrity is key to the non-linear elastic properties of chondrocytes. This study improves our understanding of the mechanical properties of articular cartilage at the single cell level.
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Affiliation(s)
- Nadeen O. Chahine
- The Feinstein Institute for Medical Research, Hofstra North Shore LIJ School of Medicine, Manhasset, New York, United States of America
| | - Craig Blanchette
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Biosciences and Biotechnology Division, Livermore, California, United States of America
| | - Cynthia B. Thomas
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Biosciences and Biotechnology Division, Livermore, California, United States of America
| | - Jeffrey Lu
- Lawrence J. Ellison Musculoskeletal Research Center, Department of Orthopaedic Surgery, University of California Davis Medical Center, Sacramento, California, United States of America
| | - Dominik Haudenschild
- Lawrence J. Ellison Musculoskeletal Research Center, Department of Orthopaedic Surgery, University of California Davis Medical Center, Sacramento, California, United States of America
| | - Gabriela G. Loots
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Biosciences and Biotechnology Division, Livermore, California, United States of America
- School of Natural Sciences, University of California Merced, Merced, California, United States of America
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Shah V, Bendele A, Dines JS, Kestler HK, Hollinger JO, Chahine NO, Hee CK. Dose-response effect of an intra-tendon application of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) in a rat Achilles tendinopathy model. J Orthop Res 2013; 31:413-20. [PMID: 22933269 DOI: 10.1002/jor.22222] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 08/07/2012] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to assess whether intra-tendon delivery of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) would improve Achilles tendon repair in a rat collagenase-induced tendinopathy model. Seven days following collagenase induction of tendinopathy, one of four intra-tendinous treatments was administered: (i) Vehicle control (sodium acetate buffer), (ii) 1.02 µg rhPDGF-BB, (iii) 10.2 µg rhPDGF-BB, or (iv) 102 µg rhPDGF-BB. Treated tendons were assessed for histopathological (e.g., proliferation, tendon thickness, collagen fiber density/orientation) and biomechanical (e.g., maximum load-to-failure and stiffness) outcomes. By 7 days post-treatment, there was a significant increase in cell proliferation with the 10.2 and 102 µg rhPDGF-BB-treated groups (p=0.049 and 0.015, respectively) and in thickness at the tendon midsubstance in the 10.2 µg of rhPDGF-BB group (p=0.005), compared to controls. All groups had equivalent outcomes by Day 21. There was a dose-dependent effect on the maximum load-to-failure, with no significant difference in the 1.02 and 102 µg rhPDGF-BB doses but the 10.2 µg rhPDGF-BB group had a significant increase in load-to-failure at 7 (p=0.003) and 21 days (p=0.019) compared to controls. The rhPDGF-BB treatment resulted in a dose-dependent, transient increase in cell proliferation and sustained improvement in biomechanical properties in a rat Achilles tendinopathy model, demonstrating the potential of rhPDGF-BB treatment in a tendinopathy application. Consequently, in this model, data suggest that rhPDGF-BB treatment is an effective therapy and thus, may be an option for clinical applications to treat tendinopathy.
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Affiliation(s)
- Vivek Shah
- Sports Medicine, BioMimetic Therapeutics, Inc., 389 Nichol Mill Lane, Franklin, Tennessee, USA
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Maidhof R, Alipui DO, Rafiuddin A, Levine M, Grande DA, Chahine NO. Emerging trends in biological therapy for intervertebral disc degeneration. Discov Med 2012; 14:401-411. [PMID: 23272692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Intervertebral disc disease is characterized by a series of deleterious changes in cellularity that lead to loss of extracellular matrix structure, altered biomechanical loading, and symptomatic pain. At present the "gold standard" of therapy is discectomy -- surgical removal of the diseased disc followed by fusion of the adjacent vertebral bodies. The procedure alleviates pain, but fusion limits range of motion and alters the mechanical loading at other spinal levels, hastening disease at previously unaffected sites. Biological therapeutics have the potential to repair damaged tissue by several means: (1) altering cell phenotype to regenerate matrix components, (2) augmenting tissue with reparative cells, (3) delivering bioactive materials to reestablish disc biomechanics and serve as a template for cell-based regeneration. Although research into biological treatments for disc degeneration has been ongoing for over a decade, few treatments have progressed to clinical testing and none are currently commercially available, primarily due to a limited understanding of disease etiology. Further work is needed to identify targets and interventional time points as disc degeneration progresses from early to later stages. This review focuses on emerging trends in biological treatments and identifies key obstacles to their clinical translation.
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Affiliation(s)
- Robert Maidhof
- The Feinstein Institute for Medical Research, Hofstra North Shore LIJ School of Medicine, Manhasset, New York 11030, USA
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Cummings SH, Grande DA, Hee CK, Kestler HK, Roden CM, Shah NV, Razzano P, Dines DM, Chahine NO, Dines JS. Effect of recombinant human platelet-derived growth factor-BB-coated sutures on Achilles tendon healing in a rat model: A histological and biomechanical study. J Tissue Eng 2012; 3:2041731412453577. [PMID: 22798983 PMCID: PMC3394411 DOI: 10.1177/2041731412453577] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose: Repairing tendon injuries with recombinant human platelet-derived growth factor-BB has potential for improving surgical outcomes. Augmentation of sutures, a critical component of surgical tendon repair, by coating with growth factors may provide a clinically useful therapeutic device for improving tendon repair. Therefore, the purpose of this study was to (a) coat Vicryl sutures with a defined dose of recombinant human platelet-derived growth factor-BB without additional coating excipients (e.g. gelatin), (b) quantify the recombinant human platelet-derived growth factor-BB released from the suture, and (c) use the recombinant human platelet-derived growth factor-BB-coated sutures to enhance tendon repair in a rat Achilles tendon transection model. Methods: Vicryl sutures were coated with 0, 0.3, 1.0, and 10.0 mg/mL concentrations of recombinant human platelet-derived growth factor-BB using a dip-coating process. In vitro release was quantified by an enzyme-linked immunosorbent assay. Acutely transected rat Achilles tendons were repaired using one of the four suture groups (n = 12 per group). Four weeks following repair, the tensile biomechanical and histological (i.e. collagen organization and angiogenesis) properties were determined. Results: A dose-dependent bolus release of recombinant human platelet-derived growth factor-BB occurred within the first hour in vitro, followed by a gradual release over 48 h. There was a significant increase in ultimate tensile strength (p < 0.01) in the two highest recombinant human platelet-derived growth factor-BB dose groups (1.9 ± 0.5 and 2.1 ± 0.5 MPa) relative to controls (1.0 ± 0.2 MPa). The modulus significantly increased (p = 0.031) with the highest recombinant human platelet-derived growth factor-BB dose group (7.2 ± 3.8 MPa) relative to all other groups (control: 3.5 ± 0.9 MPa). No significant differences were identified for the maximum load or stiffness. The histological collagen and angiogenesis scores were comparable in all groups, although there was a trend for improved collagen organization in the recombinant human platelet-derived growth factor-BB-treated groups (p = 0.054). Conclusions: The results of this study suggest that recombinant human platelet-derived growth factor-BB can be used to reproducibly coat Vicryl sutures and improve remodeling in a rat Achilles tendon transection model by significantly decreasing the resulting cross-sectional area, thus improving the material properties of the repaired tendon.
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Affiliation(s)
- Stephen H Cummings
- Department of Orthopaedic Surgery, Long Island Jewish Medical Center, New Hyde Park, NY, USA
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39
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Abstract
Osteoarthritis is a major cause of disability and pain for patients in the United States. Treatments for this degenerative disease represent a significant challenge considering the poor regenerative capacity of adult articular cartilage. Tissue-engineering techniques have advanced over the last two decades such that cartilage-like tissue can be cultivated in the laboratory for implantation. Even so, major challenges remain for creating fully functional tissue. This review article overviews some of these challenges, including overcoming limitations in nutrient supply to cartilage, improving in vitro collagen production, improving integration of engineered cartilage with native tissue, and exploring the potential for engineering full articular surface replacements.
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Affiliation(s)
| | - Eric G. Lima
- Department of Mechanical Engineering, Cooper Union, New York
| | - Liming Bian
- Department of Mechanical & Automation Engineering, Biomedical Engineering Programme, The Chinese University of Hong Kong, Hong Kong
| | - Nadeen O. Chahine
- Department of Bioengineering, The Feinstein Institute for Medical Research, Manhasset, New York
| | - Michael B. Albro
- Department of Mechanical Engineering, Columbia University, New York
| | - James L. Cook
- Comparative Orthopaedic Laboratory, University of Missouri, Columbia, Missouri
| | | | - Clark T. Hung
- Department of Biomedical Engineering, Columbia University, New York
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40
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Daher RJ, Chahine NO, Razzano P, Patwa SA, Sgaglione NJ, Grande DA. Tendon repair augmented with a novel circulating stem cell population. Int J Clin Exp Med 2011; 4:214-219. [PMID: 21977235 PMCID: PMC3182514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 09/03/2011] [Indexed: 05/31/2023]
Abstract
Tendon ruptures are common sports-related injuries that are often treated surgically by the use of sutures followed by immobilization. However, tendon repair by standard technique is associated with long healing time and often suboptimal repair. Methods to enhance tendon repair time as well as the quality of repair are currently unmet clinical needs. Our hypothesis is that the introduction of a unique stem cell population at the site of tendon transection would result in an improved rate and quality of repair. Achilles tendons of fifty-one Sprague-Dawley rats were transected and suture-repaired. In half of the rats, a biodegradable scaffold seeded with allogenic circulating stem cells was placed as an onlay to the defect site in addition to the suture repair. The other half was treated with suture alone to serve as the control group. Animals were randomized to a two-, four-, or six-week time group. At the time of necropsy, tendons were harvested and prepared for either biomechanical or histological analysis. Histological slides were evaluated in a blinded fashion with the use of a grading scale. By two weeks, the experimental group demonstrated a significant improvement in repair compared to controls with no failures. Average histological scores of 0.6 and 2.6 were observed for the experimental and control group respectively. The experimental group demonstrated complete bridging of the transection site with parallel collagen fiber arrangement. By four weeks, both groups showed a continuing trend of healing, with the scaffold group exceeding the histological quality of the tissue repaired with suture alone. Biomechanically, the experimental group had a decreasing cross-sectional area with time which was also associated with a significant increase in the ultimate tensile strength of the tendons, reaching 4.2MPa by six weeks. The experimental group also achieved a significantly higher elastic toughness by six weeks and saw an increase in the tensile modulus, reaching 31Mpa by six weeks. The use of circulating stem cells as an adjunct in tendon repair demonstrates superior biomechanical properties and an improved level of histological organization, when compared to the suture alone control group. These improvements were not previously observed when gene therapy, protein therapy, or current tissue engineering technologies were used.
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41
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Chahine NO, Albro MB, Lima EG, Wei VI, Dubois CR, Hung CT, Ateshian GA. Effect of dynamic loading on the transport of solutes into agarose hydrogels. Biophys J 2009; 97:968-75. [PMID: 19686643 DOI: 10.1016/j.bpj.2009.05.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 04/09/2009] [Accepted: 05/20/2009] [Indexed: 10/20/2022] Open
Abstract
In functional tissue engineering, the application of dynamic loading has been shown to improve the mechanical properties of chondrocyte-seeded agarose hydrogels relative to unloaded free swelling controls. The goal of this study is to determine the effect of dynamic loading on the transport of nutrients in tissue-engineered constructs. To eliminate confounding effects, such as nutrient consumption in cell-laden disks, this study examines the response of solute transport due to loading using a model system of acellular agarose disks and dextran in phosphate-buffered saline (3 and 70 kDa). An examination of the passive diffusion response of dextran in agarose confirms the applicability of Fick's law of diffusion in describing the behavior of dextran. Under static loading, the application of compressive strain decreased the total interstitial volume available for the 70 kDa dextran, compared to free swelling. Dynamic loading significantly enhanced the rate of solute uptake into agarose disks, relative to static loading. Moreover, the steady-state concentration under dynamic loading was found to be significantly greater than under static loading, for larger-molecular-mass dextran (70 kDa). This experimental finding confirms recent theoretical predictions that mechanical pumping of a porous tissue may actively transport solutes into the disk against their concentration gradient. The results of this study support the hypothesis that the application of dynamic loading in the presence of growth factors of large molecular weight may result in both a mechanically and chemically stimulating environment for tissue growth.
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Affiliation(s)
- Nadeen O Chahine
- Biomechanics & Bioengineering Research Laboratory, Feinstein Institute for Medical Research, North Shore Long Island Jewish Health System, Manhasset, New York, USA
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42
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Abstract
Lesions in articular cartilage can result in significant musculoskeletal morbidity and display unique biomechanical characteristics that make repair difficult, at best. Several surgical procedures have been devised in an attempt to relieve pain, restore function, and delay or stop the progression of cartilaginous lesions. Advanced MRI and ultrasonography protocols are currently used in the evaluation of tissue repair and to improve diagnostic capability. Other nonoperative modalities, such as injection of intra-articular hyaluronic acid or supplementary oral glucosamine and chondroitin sulfate, have shown potential efficacy as anti-inflammatory and symptom-modifying agents. The emerging field of tissue engineering, involving the use of a biocompatible, structurally and mechanically stable scaffold, has shown promising early results in cartilage tissue repair. Scaffolds incorporating specific cell sources and bioactive molecules have been the focus in this new exciting field. Further work is required to better understand the behavior of chondrocytes and the variables that influence their ability to heal articular lesions. The future of cartilage repair will probably involve a combination of treatments in an attempt to achieve a regenerative tissue that is both biomechanically stable and, ideally, identical to the surrounding native tissues.
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Affiliation(s)
- Robert J Daher
- Department of Orthopedics, Long Island Jewish Medical Center, New Hyde Park, NY, USA
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43
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Ateshian GA, Rajan V, Chahine NO, Canal CE, Hung CT. Modeling the matrix of articular cartilage using a continuous fiber angular distribution predicts many observed phenomena. J Biomech Eng 2009; 131:061003. [PMID: 19449957 DOI: 10.1115/1.3118773] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cartilage is a hydrated soft tissue whose solid matrix consists of negatively charged proteoglycans enmeshed within a fibrillar collagen network. Though many aspects of cartilage mechanics are well understood today, most notably in the context of porous media mechanics, there remain a number of responses observed experimentally whose prediction from theory has been challenging. In this study the solid matrix of cartilage is modeled with a continuous fiber angular distribution, where fibers can only sustain tension, swelled by the osmotic pressure of a proteoglycan ground matrix. It is shown that this representation of cartilage can predict a number of observed phenomena in relation to the tissue's equilibrium response to mechanical and osmotic loading, when flow-dependent and flow-independent viscoelastic effects have subsided. In particular, this model can predict the transition of Poisson's ratio from very low values in compression (approximately 0.02) to very high values in tension (approximately 2.0). Most of these phenomena cannot be explained when using only three orthogonal fiber bundles to describe the tissue matrix, a common modeling assumption used to date. The main picture emerging from this analysis is that the anisotropy of the fibrillar matrix of articular cartilage is intimately dependent on the mechanism of tensed fiber recruitment, in the manner suggested by our recent theoretical study (Ateshian, 2007, ASME J. Biomech. Eng., 129(2), pp. 240-249).
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Affiliation(s)
- Gerard A Ateshian
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
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44
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Albro MB, Chahine NO, Li R, Yeager K, Hung CT, Ateshian GA. Dynamic loading of deformable porous media can induce active solute transport. J Biomech 2008; 41:3152-7. [PMID: 18922531 DOI: 10.1016/j.jbiomech.2008.08.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/22/2008] [Accepted: 08/27/2008] [Indexed: 10/21/2022]
Abstract
Active solute transport mediated by molecular motors across porous membranes is a well-recognized mechanism for transport across the cell membrane. In contrast, active transport mediated by mechanical loading of porous media is a non-intuitive mechanism that has only been predicted recently from theory, but not yet observed experimentally. This study uses agarose hydrogel and dextran molecules as a model experimental system to explore this mechanism. Results show that dynamic loading can enhance the uptake of dextran by a factor greater than 15 over passive diffusion, for certain combinations of gel concentration and dextran molecular weight. Upon cessation of loading, the concentration reverts back to that achieved under passive diffusion. Thus, active solute transport in porous media can indeed be mediated by cyclical mechanical loading.
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Affiliation(s)
- Michael B Albro
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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45
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Albro MB, Chahine NO, Caligaris M, Wei VI, Likhitpanichkul M, Ng KW, Hung CT, Ateshian GA. Osmotic loading of spherical gels: a biomimetic study of hindered transport in the cell protoplasm. J Biomech Eng 2007; 129:503-10. [PMID: 17655471 PMCID: PMC2828939 DOI: 10.1115/1.2746371] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Osmotic loading of cells has been used to investigate their physicochemical properties as well as their biosynthetic activities. The classical Kedem-Katchalsky framework for analyzing cell response to osmotic loading, which models the cell as a fluid-filled membrane, does not generally account for the possibility of partial volume recovery in response to loading with a permeating osmolyte, as observed in some experiments. The cell may be more accurately represented as a hydrated gel surrounded by a semi-permeable membrane, with the gel and membrane potentially exhibiting different properties. To help assess whether this more elaborate model of the cell is justified, this study investigates the response of spherical gels to osmotic loading, both from experiments and theory. The spherical gel is described using the framework of mixture theory. In the experimental component of the study alginate is used as the model gel, and is osmotically loaded with dextran solutions of various concentrations and molecular weight, to verify the predictions from the theoretical analysis. Results show that the mixture framework can accurately predict the transient and equilibrium response of alginate gels to osmotic loading with dextran solutions. It is found that the partition coefficient of dextran in alginate regulates the equilibrium volume response and can explain partial volume recovery based on passive transport mechanisms. The validation of this theoretical framework facilitates future investigations of the role of the protoplasm in the response of cells to osmotic loading.
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Affiliation(s)
- Michael B Albro
- Department of Mechanical Engineering, Columbia University, 500 West 120th Street, MC 4703, New York, NY 10027, USA
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46
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Abstract
Chondrocytes are responsible for the elaboration and maintenance of the extracellular (EC) matrix in articular cartilage, and previous studies have demonstrated that mechanical loading modulates the biosynthetic response of chondrocytes in cartilage explants. The goal of this study is to investigate the deformation behaviour of the chondrocyte and its microenvironment under transient loading, in order to address the relationship between the applied dynamic deformation and cellular strain. In-situ strain measurements were performed on cells in the middle (MZ) zone at early time points during ramp loading and at equilibrium. In this study, we characterized the behaviour of cartilage at the zonal and cellular levels under compressive loading using digital image analysis on miniature samples tested in a custom microscopy-based loading device. The experimental results indicate that significant strain amplification occurs in the microenvironment of the cell, with the minimum (compressive) principal strain found to be nearly 7X higher in the intracellular region (IC), and ~5X higher in the pericellular (PC) matrix than in the EC matrix at peak ramp. A similar strain amplification mechanism was observed in the maximum (tensile) principal strain, and this behaviour persisted even after equilibrium was reached. The experimental results of this study were interpreted in the context of a finite element model of chondrocyte deformation, which modelled the cell as a homogeneous gel, possessing either a spherical or ellipsoidal geometry, surrounded by a semi permeable membrane, and accounted for the presence of a PC matrix. The results of the FEA demonstrate significant strain amplification mechanism in the IC region, greater than had previously been suggested in earlier computational studies of cell-EC matrix interactions. Based on the FEA, this outcome is understood to result from the large disparity between EC matrix and intracellular properties. The results of this study suggest that mechanotransduction of chondrocytes may be significantly mediated by this strain amplification mechanism during loading.
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Affiliation(s)
- Nadeen O Chahine
- Musculoskeletal Biomechanics Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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47
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Basalo IM, Chahine NO, Kaplun M, Chen FH, Hung CT, Ateshian GA. Chondroitin sulfate reduces the friction coefficient of articular cartilage. J Biomech 2007; 40:1847-54. [PMID: 17084404 DOI: 10.1016/j.jbiomech.2006.07.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 07/24/2006] [Indexed: 11/27/2022]
Abstract
The objective of this study was to investigate the effect of chondroitin sulfate (CS)-C on the frictional response of bovine articular cartilage. The main hypothesis is that CS decreases the friction coefficient of articular cartilage. Corollary hypotheses are that viscosity and osmotic pressure are not the mechanisms that mediate the reduction in the friction coefficient by CS. In Experiment 1, bovine articular cartilage samples (n=29) were tested in either phosphate buffered saline (PBS) or in PBS containing 100mg/ml of CS following 48h incubation in PBS or in PBS+100mg/ml CS (control specimens were not subjected to any incubation). In Experiment 2, samples (n=23) were tested in four different solutions: PBS, PBS+100mg/ml CS, and PBS+polyethylene glycol (PEG) (133 or 170mg/ml). In Experiment 3, samples (n=18) were tested in three solutions of CS (0, 10 and 100mg/ml). Frictional tests (cartilage-on-glass) were performed under constant stress (0.5MPa) for 3600s and the time-dependent friction coefficient was measured. Samples incubated or tested in a 100mg/ml CS solution exhibited a significantly lower equilibrium friction coefficient than the respective PBS control. PEG solutions delayed the rise in the friction coefficient relative to the PBS control, but did not reduce the equilibrium value. Testing in PBS+10mg/ml of CS did not cause any significant decrease in the friction coefficient. In conclusion, CS at a concentration of 100mg/ml significantly reduces the friction coefficient of bovine articular cartilage and this mechanism is neither mediated by viscosity nor osmolarity. These results suggest that direct injection of CS into the joint may provide beneficial tribological effects.
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Affiliation(s)
- Ines M Basalo
- Department of Mechanical Engineering, Columbia University, 500 West 120th Street, 220 SW Mudd, MC 4703, New York, NY 10027, USA
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48
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Chahine NO, Ateshian GA, Hung CT. The effect of finite compressive strain on chondrocyte viability in statically loaded bovine articular cartilage. Biomech Model Mechanobiol 2006; 6:103-11. [PMID: 16821016 DOI: 10.1007/s10237-006-0041-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2005] [Accepted: 01/06/2006] [Indexed: 11/29/2022]
Abstract
Recent studies have reported that certain regimes of compressive loading of articular cartilage result in increased cell death in the superficial tangential zone (STZ). The objectives of this study were (1) to test the prevalent hypothesis that preferential cell death in the STZ results from excessive compressive strain in that zone, relative to the middle and deep zones, by determining whether cell death correlates with the magnitude of compressive strain and (2) to test the corollary hypothesis that the viability response of cells is uniform through the thickness of the articular layer when exposed to the same loading environment. Live cartilage explants were statically compressed by approximately 65% of their original thickness, either normal to the articular surface (axial loading) or parallel to it (transverse loading). Cell viability after 12 h was compared to the local strain distribution measured by digital image correlation. Results showed that the strain distribution in the axially loaded samples was highest in the STZ (77%) and lowest in the deep zone (55%), whereas the strain was uniformly distributed in the transversely loaded samples (64%). In contrast, axially and transversely loaded samples exhibited very similar profiles of cell death through the depth, with a preferential distribution in the STZ. Unloaded control samples showed negligible cell death. Thus, under prolonged static loading, depth-dependent variations in chondrocyte death did not correlate with the local depth-dependent compressive strain, and the prevalent hypothesis must be rejected. An alternative hypothesis, suggested by these results, is that superficial zone chondrocytes are more vulnerable to prolonged static loading than chondrocytes in the middle and deep zones.
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Affiliation(s)
- N O Chahine
- Musculoskeletal Biomechanics Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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49
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Moffat KL, Sun WHS, Chahine NO, Pena PE, Doty SB, Hung CT, Ateshian GA, Lu HH. Characterization of the mechanical properties and mineral distribution of the anterior cruciate ligament-to-bone insertion site. Conf Proc IEEE Eng Med Biol Soc 2006; 2006:2366-2369. [PMID: 17946954 DOI: 10.1109/iembs.2006.259299] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The anterior cruciate ligament (ACL) connects the femur to the tibia through direct insertion sites and functions as the primary restraint to anterior tibial translation. The ACL-to-bone insertion sites exhibit a complex structure consisting of four zones of varied cellular and matrix components, consisting of ligament, non-mineralized fibrocartilage, mineralized fibrocartilage and bone, which allow for the effective load transfer from ligament to bone, thereby minimizing stress concentrations and preventing failure. The mineral content and distribution within the fibrocartilage region may be an important structural component of the insertion site which may influence the mechanical properties. The goals of this study are to characterize the compressive mechanical properties of the fibrocartilage region of the ACL-to-bone insertion site and evaluate how the mineral distribution at the interface relates to these compressive properties. In order to determine the compressive mechanical properties we have utilized a novel microscopic mechanical testing method combined with digital image correlation and employed energy dispersive X-ray analysis (EDAX) in order to evaluate the mineral content and distribution across the femoral and tibial insertion sites. The results reveal that a regional mineral gradient is observed across the fibrocartilage which corresponds to depth-dependent variations in compressive mechanical properties. This depth- dependent mechanical inhomogeneity strongly correlates to the increase in mineral content of the mineralized fibrocartilage (MFC) region compared to the non-mineralized fibrocartilage (NFC). Additionally, the tibial NFC and MFC mechanical properties are greater than those of the femoral NFC and MFC which corresponds to a greater mineral content in the NFC and MFC regions of the tibial insertion. The findings of this study suggest that a structure-function relationship exists at the ACL-to-bone interface.
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Affiliation(s)
- Kristen L Moffat
- Biomaterials & Interface Tissue Engineering Laboratory, Columbia University, New York, NY 10021, USA
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50
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Chahine NO, Chen FH, Hung CT, Ateshian GA. Direct measurement of osmotic pressure of glycosaminoglycan solutions by membrane osmometry at room temperature. Biophys J 2005; 89:1543-50. [PMID: 15980166 PMCID: PMC1366659 DOI: 10.1529/biophysj.104.057315] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Articular cartilage is a hydrated soft tissue composed of negatively charged proteoglycans fixed within a collagen matrix. This charge gradient causes the tissue to imbibe water and swell, creating a net osmotic pressure that enhances the tissue's ability to bear load. In this study we designed and utilized an apparatus for directly measuring the osmotic pressure of chondroitin sulfate, the primary glycosaminoglycan found in articular cartilage, in solution with varying bathing ionic strength (0.015 M, 0.15 M, 0.5 M, 1 M, and 2 M NaCl) at room temperature. The osmotic pressure (pi) was found to increase nonlinearly with increasing chondroitin sulfate concentration and decreasing NaCl ionic bath environment. Above 1 M NaCl, pi changes negligibly with further increases in salt concentration, suggesting that Donnan osmotic pressure is negligible above this threshold, and the resulting pressure is attributed to configurational entropy. Results of the current study were also used to estimate the contribution of osmotic pressure to the stiffness of cartilage based on theoretical and experimental considerations. Our findings indicate that the osmotic pressure resulting from configurational entropy is much smaller in cartilage (based on an earlier study on bovine articular cartilage) than in free solution. The rate of change of osmotic pressure with compressive strain is found to contribute approximately one-third of the compressive modulus (H(A)(eff)) of cartilage (Pi approximately H(A)(eff)/3), with the balance contributed by the intrinsic structural modulus of the solid matrix (i.e., H(A) approximately 2H(A)(eff)/3). A strong dependence of this intrinsic modulus on salt concentration was found; therefore, it appears that proteoglycans contribute structurally to the magnitude of H(A), in a manner independent of osmotic pressure.
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Affiliation(s)
- Nadeen O Chahine
- Musculoskeletal Biomechanics Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA
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