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Kiapour A, Seim HB, Atkinson BL, Lalor PA, Block JE. Bone Mineralization and Spinal Fusion Evaluation of a Truss-based Interbody Fusion Device: Ovine Finite Element Analysis with Confirmatory In Vivo Outcomes. Spine (Phila Pa 1976) 2022; 47:E319-E327. [PMID: 34593736 PMCID: PMC8912963 DOI: 10.1097/brs.0000000000004256] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Finite element analysis (FEA) and in vivo ovine spinal interbody fusion study. OBJECTIVE To determine comparative load-induced strain amplitudes, bone mineralization and fusion outcomes associated with different diameter struts in a truss-based interbody fusion device. SUMMARY OF BACKGROUND DATA Additive manufacturing technology has been employed to develop implants that actively participate in the fusion process. The truss device enables the optimal transfer of compressive and tensile stresses via the struts. Mechanobiologic principles postulate that strut diameter can be regulated to allow different magnitudes of strain distribution within the struts which may affect fusion rates. METHODS Modeling of strain distributions as a function of strut diameter (0.75, 1.0, 1.25, and 1.5 mm) employed FEA that simulated physiologic loading conditions. A confirmatory in vivo ovine lumbar spinal interbody fusion study compared fusion scores and bone histomorphometric variables for cages with 0.75 and 1.5 mm strut diameters. Outcomes were compared at 3-, 6-, and 12-month follow-up intervals. RESULTS FEA showed an inverse association between strut diameter and peak strain amplitude. Cages with 1.0, 1.25, and 1.5 mm struts had peak strain values that were 36%, 60%, and 73% lower than the 0.75 mm strut strain value. In vivo results showed the mean fusion score for the 0.75 mm diameter strut cage was significantly greater by 3-months versus the 1.5 mm strut cage, and remained significantly higher at each subsequent interval (P < 0.001 for all comparisons). Fusion rates were 95%, 100%, and 100% (0.75 mm) and 72.7%, 86.4%, and 95.8% (1.5 mm) at 3, 6, and 12 months. Thinner struts had greater mineralized bone tissue and less fibrous/chondral tissue than the thicker struts at each follow-up. CONCLUSION Validating FEA estimates, cages with smaller diameter struts exhibited more rapid fusion consolidation and more aggressive osseointegration compared with cages with larger diameters struts.Level of Evidence: 4.
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Affiliation(s)
- Ali Kiapour
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Coric D, Bullard DE, Patel VV, Ryaby JT, Atkinson BL, He D, Guyer RD. Pulsed electromagnetic field stimulation may improve fusion rates in cervical arthrodesis in high-risk populations. Bone Joint Res 2018; 7:124-130. [PMID: 29437635 PMCID: PMC5895946 DOI: 10.1302/2046-3758.72.bjr-2017-0221.r1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES Pulsed electromagnetic field (PEMF) stimulation was evaluated after anterior cervical discectomy and fusion (ACDF) procedures in a randomized, controlled clinical study performed for United States Food and Drug Administration (FDA) approval. PEMF significantly increased fusion rates at six months, but 12-month fusion outcomes for subjects at elevated risk for pseudoarthrosis were not thoroughly reported. The objective of the current study was to evaluate the effect of PEMF treatment on subjects at increased risk for pseudoarthrosis after ACDF procedures. METHODS Two evaluations were performed that compared fusion rates between PEMF stimulation and a historical control (160 subjects) from the FDA investigational device exemption (IDE) study: a post hoc (PH) analysis of high-risk subjects from the FDA study (PH PEMF); and a multicentre, open-label (OL) study consisting of 274 subjects treated with PEMF (OL PEMF). Fisher's exact test and multivariate logistic regression was used to compare fusion rates between PEMF-treated subjects and historical controls. RESULTS In separate comparisons of PH PEMF and OL PEMF groups to the historical control group, PEMF treatment significantly (p < 0.05, Fisher's exact test) increased the fusion rate at six and 12 months for certain high-risk subjects who had at least one clinical risk factor of being elderly, a nicotine user, osteoporotic, or diabetic; and for those with at least one clinical risk factor and who received at least a two- or three-level arthrodesis. CONCLUSION Adjunctive PEMF treatment can be recommended for patients who are at high risk for pseudoarthrosis.Cite this article: D. Coric, D. E. Bullard, V. V. Patel, J. T. Ryaby, B. L. Atkinson, D. He, R. D. Guyer. Pulsed electromagnetic field stimulation may improve fusion rates in cervical arthrodesis in high-risk populations. Bone Joint Res 2018;7:124-130. DOI: 10.1302/2046-3758.72.BJR-2017-0221.R1.
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Affiliation(s)
- D Coric
- Carolina Neurosurgery and Spine Associates, Charlotte, North Carolina, USA
| | - D E Bullard
- Triangle Neurosurgery, 1540 Sunday Drive, Suite 214, Raleigh, North Carolina 27607, USA
| | - V V Patel
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, 13001 East 17th Place, Aurora, Colorado 80045, USA
| | - J T Ryaby
- Clinical Affairs Department, Orthofix, Inc., 3451 Plano Parkway, Lewisville, Texas 75056, USA
| | - B L Atkinson
- Atkinson Biologics Consulting, Highlands Ranch, Colorado, USA
| | - D He
- Analytical Solutions Group, Inc, North Potomac, Maryland, USA
| | - R D Guyer
- TBIRF, Texas Back Institute, 6020 West Parker Road Suite 200, Plano, Texas 75093, USA
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Peppers TA, Bullard DE, Vanichkachorn JS, Stanley SK, Arnold PM, Waldorff EI, Hahn R, Atkinson BL, Ryaby JT, Linovitz RJ. Prospective clinical and radiographic evaluation of an allogeneic bone matrix containing stem cells (Trinity Evolution® Viable Cellular Bone Matrix) in patients undergoing two-level anterior cervical discectomy and fusion. J Orthop Surg Res 2017; 12:67. [PMID: 28446192 PMCID: PMC5407027 DOI: 10.1186/s13018-017-0564-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [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: 09/15/2016] [Accepted: 04/12/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trinity Evolution® (TE), a viable cellular bone allograft, previously demonstrated high fusion rates and no safety-related concerns after single-level anterior cervical discectomy and fusion (ACDF) procedures. This prospective multicenter clinical study was performed to assess the radiographic and clinical outcomes of TE in subjects undergoing two-level ACDF procedures. METHODS In a prospective, multicenter study, 40 subjects that presented with symptomatic cervical degeneration at two adjacent vertebral levels underwent instrumented ACDF using TE autograft substitute in a polyetherethereketone (PEEK) cage. At 12 months, radiographic fusion status was evaluated by dynamic motion plain radiographs and thin cut CT with multiplanar reconstruction by a panel that was blinded to clinical outcome. Fusion success was defined by angular motion (≤4°) and the presence of bridging bone across the adjacent vertebral endplates. Clinical pain and function assessments included the Neck Disability Index (NDI), neck and arm pain as evaluated by visual analog scales (VAS), and SF-36 at both 6 and 12 months. RESULTS At both 6 and 12 months, all clinical outcome scores (SF-36, NDI, and VAS pain) improved significantly (p < 0.05) compared to baseline values. There were no adverse events or infections that were attributed to the graft material, no subjects that required revisions, and no significant decreases to mean neurological evaluations at any time as compared to baseline. At 12 months, the per subject and per level fusion rate was 89.4 and 93.4%, respectively. Subgroup analysis of subjects with risk factors for pseudoarthrosis (current or former smokers, diabetic, or obese/extremely obese) compared to those without risk factors demonstrated no significant differences in fusion rates. CONCLUSIONS Patients undergoing two-level ACDF with TE in combination with a PEEK interbody spacer and supplemental anterior fixation had a high rate of fusion success without any serious adverse events related to the graft material. TRIAL REGISTRATION Trinity Evolution in Anterior Cervical Disectomy and Fusion (ACDF) NCT00951938.
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Affiliation(s)
- Timothy A Peppers
- Seaside Spine Medical Associates, 320 Santa Fe Dr., Suite 300, Encinitas, CA, 92024, USA
| | | | | | - Scott K Stanley
- Denver-Vail Orthopedics, P.C., 8101 E. Lowry Blvd., Suite 260, Denver, CO, 80230, USA
| | - Paul M Arnold
- Kansas University Medical Center, 3901 Rainbow Blvd Ste 2B, Kansas City, KS, 66160, USA
| | - Erik I Waldorff
- Orthofix, Inc., 3451 Plano Parkway, Lewisville, TX, 75056, USA
| | - Rebekah Hahn
- Orthofix, Inc., 3451 Plano Parkway, Lewisville, TX, 75056, USA
| | | | - James T Ryaby
- Orthofix, Inc., 3451 Plano Parkway, Lewisville, TX, 75056, USA
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Musante DB, Firtha ME, Atkinson BL, Hahn R, Ryaby JT, Linovitz RJ. Clinical evaluation of an allogeneic bone matrix containing viable osteogenic cells in patients undergoing one- and two-level posterolateral lumbar arthrodesis with decompressive laminectomy. J Orthop Surg Res 2016; 11:63. [PMID: 27233773 PMCID: PMC4884431 DOI: 10.1186/s13018-016-0392-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 01/24/2016] [Accepted: 04/25/2016] [Indexed: 02/06/2023] Open
Abstract
Background Trinity Evolution® cellular bone allograft (TE) possesses the osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study is to evaluate the radiographic and clinical outcomes when TE is used as a graft extender in combination with locally derived bone in one- and two-level instrumented lumbar posterolateral arthrodeses. Methods In this retrospective evaluation, a consecutive series of subject charts that had posterolateral arthrodesis with TE and a 12-month radiographic follow-up were evaluated. All subjects were diagnosed with degenerative disc disease, radiculopathy, stenosis, and decreased disc height. At 2 weeks and at 3 and 12 months, plain radiographs were performed and the subject’s back and leg pain (VAS) was recorded. An evaluation of fusion status was performed at 12 months. Results The population consisted of 43 subjects and 47 arthrodeses. At 12 months, a fusion rate of 90.7 % of subjects and 89.4 % of surgical levels was observed. High-risk subjects (e.g., diabetes, tobacco use, etc.) had fusion rates comparable to normal patients. Compared with the preoperative leg or back pain level, the postoperative pain levels were significantly (p < 0.0001) improved at every time point. There were no adverse events attributable to TE. Conclusions Fusion rates using TE were higher than or comparable to fusion rates with autologous iliac crest bone graft that have been reported in the recent literature for posterolateral fusion procedures, and TE fusion rates were not adversely affected by several high-risk patient factors. The positive results provide confidence that TE can safely replace autologous iliac crest bone graft when used as a bone graft extender in combination with locally derived bone in the setting of posterolateral lumbar arthrodesis in patients with or without risk factors for compromised bone healing. Trial registration Because of the retrospective nature of this study, the trial was not registered.
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Affiliation(s)
- David B Musante
- Triangle Orthopedics, 120 William Penn Plaza, Durham, NC, 27704, USA.
| | - Michael E Firtha
- Campbell School of Osteopathic Medicine, Campbell University, 4350 US-421, Lillington, NC, 27546, USA
| | - Brent L Atkinson
- Atkinson Biologics Consulting, 9189 Fox Fire Way, Highlands Ranch, Littleton, CO, 80129, USA
| | - Rebekah Hahn
- Orthofix Inc., 3451 Plano Parkway, Lewisville, TX, 75056, USA
| | - James T Ryaby
- Orthofix Inc., 3451 Plano Parkway, Lewisville, TX, 75056, USA
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Jones CP, Loveland J, Atkinson BL, Ryaby JT, Linovitz RJ, Nunley JA. Prospective, Multicenter Evaluation of Allogeneic Bone Matrix Containing Viable Osteogenic Cells in Foot and/or Ankle Arthrodesis. Foot Ankle Int 2015; 36:1129-37. [PMID: 25976919 DOI: 10.1177/1071100715586181] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [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: 02/01/2023]
Abstract
BACKGROUND Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses. METHODS A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively. RESULTS At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvements in pain, function, and QOL were observed, and fusion correlated with both function and QOL outcomes at 6 and 12 months. There were no adverse events attributable to CBA. CONCLUSION Fusion rates using CBA were higher than or comparable to fusion rates with autograft that have been reported in the recent literature, and CBA fusion rates were not adversely affected by several high-risk patient factors. CBA was a safe and effective graft material to achieve fusion in patients with compromised bone healing and may provide an effective autograft replacement for foot and/or ankle arthrodeses. LEVEL OF EVIDENCE Level II, prospective study.
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Affiliation(s)
| | | | | | | | | | - James A Nunley
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
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Shi Y, Niedzinski JR, Samaniego A, Bogdansky S, Atkinson BL. Adipose-derived stem cells combined with a demineralized cancellous bone substrate for bone regeneration. Tissue Eng Part A 2012; 18:1313-21. [PMID: 22500696 DOI: 10.1089/ten.tea.2011.0357] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mesenchymal stem cells (MSCs) isolated from cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation in vivo and ex vivo.( 1-6 ) The hypothesis tested whether a demineralized cancellous bone matrix (DCBM) can provide an effective substrate for selection and retention of stem cells derived from the stromal vascular fraction (SVF) of adipose. Human cadaveric adipose tissue was recovered from a donor and digested. The resulting SVF-containing MSCs were seeded onto the demineralized bone allografts, after which the nonadherent cells were washed off. The MSCs were characterized using a flow cytometer and tri-lineage differentiation (osteogenesis, chondrogenesis, and adipogenesis) in vitro. The stem cell-seeded allografts were also characterized for cell number, adherence to the DCBM, osteogenic activity (alkaline phosphatase and Alizarin Red staining), and bone morphorgenic protein (BMP) quantity. Flow cytometry identified a mean total of 7.2% MSCs in SVF and 87.2% MSCs after culture. The stem cells showed the capability of differentiating into bone, cartilage, and fat. On the 21 stem cell-seeded bone allografts, there were consistent, attached, viable cells (100,744±22,762 cells/cube). An assessment of donor age, gender, and body mass index revealed no significant differences in cell numbers. Enzyme-linked immunosorbent assay revealed the presence of BMP-2 and BMP-7. In conclusion, this bone graft contains three key elements for bone regeneration: adhered osteogenic stem cells, 3D osteoconductive bone scaffold, and osteoinductive BMP signal. It therefore has the potential to be effective for bone regeneration.
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Affiliation(s)
- Yaling Shi
- AlloSource, 6278 S. Troy Circle, Centennial, CO 80111, USA.
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Cunningham BW, Atkinson BL, Hu N, Kikkawa J, Jenis L, Bryant J, Zamora PO, McAfee PC. Ceramic granules enhanced with B2A peptide for lumbar interbody spine fusion: an experimental study using an instrumented model in sheep. J Neurosurg Spine 2009; 10:300-7. [PMID: 19441986 DOI: 10.3171/2009.1.spine08565] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECT New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. METHODS Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. RESULTS All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. CONCLUSIONS Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
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Affiliation(s)
- Bryan W Cunningham
- Orthopaedic Spinal Research Laboratory, St. Joseph Medical Center, Towson, MD, USA
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Rodeo SA, Potter HG, Kawamura S, Turner AS, Kim HJ, Atkinson BL. Biologic augmentation of rotator cuff tendon-healing with use of a mixture of osteoinductive growth factors. J Bone Joint Surg Am 2007; 89:2485-97. [PMID: 17974893 DOI: 10.2106/jbjs.c.01627] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [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 Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repair. Since healing of such a repair is dependent on bone ingrowth into the repaired tendon, we hypothesized that osteoinductive growth factors would improve rotator cuff tendon-healing. METHODS Seventy-two skeletally mature sheep underwent detachment of the infraspinatus tendon followed by immediate repair. The animals received one of three treatments at the tendon-bone interface: (1) an osteoinductive bone protein extract on a Type-I collagen sponge carrier, (2) the collagen sponge carrier alone, and (3) no implant. The animals were killed at six and twelve weeks, and the repaired rotator cuff was evaluated with use of magnetic resonance imaging, plain radiographs, histologic analysis, and biomechanical testing. RESULTS A gap consistently formed between the end of the repaired tendon and bone in this model, with reparative scar tissue and new bone spanning the gap. Magnetic resonance imaging showed that the volume of newly formed bone (p < 0.05) and soft tissue (p < 0.05) in the tendon-bone gap were greater in the growth factor-treated animals compared with the collagen sponge control group at both time-points. Histologic analysis showed a fibrovascular tissue in the interface between tendon and bone, with a more robust fibrocartilage zone between the bone and the tendon in the growth factor-treated animals. The repairs that were treated with the osteoinductive growth factors had significantly greater failure loads at six weeks and twelve weeks (p < 0.05); however, when the data were normalized by tissue volume, there were no differences between the groups, suggesting that the treatment with growth factor results in the formation of poor-quality scar tissue rather than true tissue regeneration. The repairs that were treated with the collagen sponge carrier alone had significantly greater stiffness than the growth factor-treated group at twelve weeks (p = 0.005). CONCLUSIONS This model tests the effects of growth factors on scar tissue formation in a gap between tendon and bone. The administration of osteoinductive growth factors resulted in greater formation of new bone, fibrocartilage, and soft tissue, with a concomitant increase in tendon attachment strength but less stiffness than repairs treated with the collagen sponge carrier alone.
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Affiliation(s)
- Scott A Rodeo
- The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
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Lin X, Elliot JJ, Carnes DL, Fox WC, Peña LA, Campion SL, Takahashi K, Atkinson BL, Zamora PO. Augmentation of osseous phenotypes in vivo with a synthetic peptide. J Orthop Res 2007; 25:531-9. [PMID: 17149745 DOI: 10.1002/jor.20303] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [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] [Indexed: 02/04/2023]
Abstract
The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cells were stimulated with BMP-2, an osteoinductive growth factor. B2A2-K-NS significantly enhanced the effects of BMP-2-induced alkaline phosphatase activity and mineralization. In the absence of BMP-2, B2A2-K-NS did not have an effect on these endpoints. Based on these observations, in vivo studies were conducted to evaluate if B2A2-K-NS could augment osseous phenotypes in an osteoinductive environment in which BMP-2 should be present. In one study, human demineralized bone matrix (DBM) was used to generate an osteoinductive environment and the effects of B2A2-K-NS on ectopic mineralization of subcutaneous implants evaluated. In the second study, a noncritical sized defect in rabbit ulnas with inherent reparative capacity was used as the osteoinductive environment and was treated with or without B2A2-K-NS. In the DBM studies, B2A2-K-NS augmented mineralization as determined using a combination of radiographic analysis and von Kossa staining at 4 weeks postimplant. In the rabbit ulna model, B2A2-K-NS significantly increased the radiographic bone density in the defects compared to carrier-only or no-treatment controls after 6 weeks. Histological staining confirmed that B2A2-K-NS generated a pronounced bone repair response. The results are consistent with the hypothesis that B2A2-K-NS augments osseous phenotypes in an osteoinductive environment, and suggests that B2A2-K-NS may have clinical utility.
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Affiliation(s)
- Xinhua Lin
- BioSurface Engineering Technologies, Inc., 9430 Key West Avenue, Suite 220, Rockville, Maryland 20850, USA.
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Hole BB, Schwarz JA, Gilbert JL, Atkinson BL. A study of biologically active peptide sequences (P-15) on the surface of an ABM scaffold (PepGen P-15) using AFM and FTIR. J Biomed Mater Res A 2005; 74:712-21. [PMID: 16021612 DOI: 10.1002/jbm.a.30331] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cellular response to any biomaterial surface is governed by a number of factors including topography, surface chemistry, surface charge, structural heterogeneity, and physiological conditions. Understanding these factors at the nanoscale level is crucial to develop improved biomaterials. Any changes in these properties due to surface modifications need to be addressed properly, as they could have significant impact on the cellular interaction with biomaterials. In this study, the topography and surface chemistry of commercially available tissue engineered xenograft, PepGen P-15 [comprised of a synthetic peptide P-15 irreversibly attached to anorganic bovine bone mineral (OsteoGraf/-N)] was studied using Atomic Force Microscopy (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). FTIR confirmed the presence of the peptide on the surface of PepGen P-15. Changes in the peptide conformation, which includes a decrease in the beta-strand accompanied by an increase in unordered structures/random coil structures after attachment on OsteoGraf/-N is observed. Specific functional groups, which are involved in the binding mechanism, are identified. The results suggest that the attachment of the peptide on OsteoGraf/-N occurs via a specific surface docking ionic interaction involving the C-terminal carboxylic group on the peptide with positive domains generated by hydroxyl vacancies on the apatite surface.
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Affiliation(s)
- Bhushan B Hole
- Department of Chemical Engineering and Material Science, Syracuse University, Syracuse, New York 13244-1240, USA.
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Vastardis S, Yukna RA, Mayer ET, Atkinson BL. Periodontal Regeneration With Peptide-Enhanced Anorganic Bone Matrix in Particulate and Putty Form in Dogs. J Periodontol 2005; 76:1690-6. [PMID: 16253091 DOI: 10.1902/jop.2005.76.10.1690] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Peptide-enhanced (using the peptide 15 [P-15] synthetic peptide) anorganic bone matrix (ABM) particulate (PPart) grafts have demonstrated clinical and histologic success in human periodontal defects. Dispersion of ABM/P-15 in sodium hyaluronate carrier (PPutty) improves the handling properties of the graft material. The healing of ABM/P-15 particulate and ABM/P-15 putty was compared in critical-sized fenestration defects in 16 mongrel dogs. METHODS After full thickness flap reflection, 7 mm diameter fenestrations were made with a trephine in the mid-root of both maxillary canines in each dog. Bone, periodontal ligament, and cementum were removed as completely as possible with hand root planing within the trephine-produced notches. By random allocation, each defect was filled with PPart or PPutty, and the flaps were closed with sutures. One dog contributing two defects served as a negative control. Block sections were retrieved at 3 and 8 weeks for histologic processing. Three 6-mu step serial sections in the center of the defects were used for analysis. Parameters measured included the original length of the wound, linear amount of periodontal regeneration including new cementum, bone and connective tissue, and area measurements of new bone and remaining particles. PPutty and PPart results were compared for significant differences using the Wilcoxon rank sum test. RESULTS Clinical healing was uneventful in all cases. There was no evidence of inflammation or adverse tissue reactions with either material. The controls showed minimal regeneration at the periphery of the defect. Histomorphometric evaluation of the grafted defects revealed the following: at 3 weeks, there was minimal new bone formation (occupying 4.2% of the grafted area for the PPutty and 1.2% for the PPart). The grafted particles occupied 21.2% and 35.6% of the area for the PPutty and PPart, respectively (P = 0.039). At 8 weeks, there was a tendency for greater new bone formation compared to 3 weeks with both materials. There was significantly more new bone with the PPutty (49.3%) compared to the PPart (14.8%) (P = 0.045). The grafted particles occupied 7.9% and 17% of the grafted area for the PPutty and PPart, respectively (no significant difference). There were no significant differences for any of the linear measurements. ABM/P-15 PPutty had superior handling characteristics. CONCLUSIONS Both ABM/P-15 materials yielded satisfactory healing and resulted in the greater regeneration of fenestration defects in dogs at 8 weeks compared to controls. In addition, AMB/P-15 putty resulted in more bone formation compared to ABM/P-15 particulate.
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Affiliation(s)
- Sotirios Vastardis
- Periodontics Department, Louisiana State University School of Dentistry, New Orleans, LA 70119, USA.
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Anderson K, Seneviratne AM, Izawa K, Atkinson BL, Potter HG, Rodeo SA. Augmentation of tendon healing in an intraarticular bone tunnel with use of a bone growth factor. Am J Sports Med 2001; 29:689-98. [PMID: 11734478 DOI: 10.1177/03635465010290060301] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [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] [Indexed: 01/31/2023]
Abstract
We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a bone tunnel in a rabbit anterior cruciate ligament-reconstruction model. Seventy rabbits underwent bilateral anterior cruciate ligament reconstructions with a semitendinosus tendon graft. One limb received a collagen sponge carrier vehicle containing a mixture of bone-derived proteins while the contralateral limb was treated with either no sponge or a sponge without bone-derived proteins. The reconstruction was evaluated at 2, 4, or 8 weeks with histologic, biomechanical, and magnetic resonance imaging analysis. Histologic analysis demonstrated that specimens treated with bone-derived proteins had a more consistent, dense interface tissue and closer apposition of new bone to the graft, with occasional formation of a fibrocartilaginous interface, when compared with control specimens. The treated specimens had significantly higher load-to-failure rates than did control specimens. Treatment with bone-derived proteins resulted in an average increase in tensile strength of 65%. The treated specimens were stronger than control specimens at each time point, but the difference was greatest at 8 weeks. On the basis of signal characteristics and new bone formation, magnetic resonance imaging was useful for predicting which limb was treated, the site of failure, and the limbs with higher load-to-failure values. This study demonstrates the potential for augmenting tendon healing in an intraarticular bone tunnel using an osteoinductive growth factor.
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Affiliation(s)
- K Anderson
- William Clay Ford Center for Athletic Medicine, Detroit, Michigan 48202, USA
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Chenite A, Chaput C, Wang D, Combes C, Buschmann MD, Hoemann CD, Leroux JC, Atkinson BL, Binette F, Selmani A. Novel injectable neutral solutions of chitosan form biodegradable gels in situ. Biomaterials 2000; 21:2155-61. [PMID: 10985488 DOI: 10.1016/s0142-9612(00)00116-2] [Citation(s) in RCA: 865] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A novel approach to provide, thermally sensitive neutral solutions based on chitosan/polyol salt combinations is described. These formulations possess a physiological pH and can be held liquid below room temperature for encapsulating living cells and therapeutic proteins; they form monolithic gels at body temperature. When injected in vivo the liquid formulations turn into gel implants in situ. This system was used successfully to deliver biologically active growth factors in vivo as well as an encapsulating matrix for living chondrocytes for tissue engineering applications. This study reports for the first time the use of polymer/polyol salt aqueous solutions as gelling systems, suggesting the discovery of a prototype for a new family of thermosetting gels highly compatible with biological compounds.
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Affiliation(s)
- A Chenite
- Center for Applied Research on Polymers, Chemical Engineering Department and Institute of Biomedical Engineering, Ecole Polytechnique of Montreal, PQ, Canada.
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Atkinson BL, Fantle KS, Benedict JJ, Huffer WE, Gutierrez-Hartmann A. Combination of osteoinductive bone proteins differentiates mesenchymal C3H/10T1/2 cells specifically to the cartilage lineage. J Cell Biochem 1997; 65:325-39. [PMID: 9138089] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
During embryonic development, cartilage formation involves the condensation of mesenchymal stem cells and a series of maturation steps that ultimately results in the mineralized hypertrophic chondrocyte. The embryonic, murine, mesenchymal stem cell line, C3H/10T1/2, is pluripotent; exposure to azacytidine or to bone morphogenetic protein-2 or -4 results in low rates of differentiation to three mesengenic lineages. In contrast to previous studies, we report conditions for 10T1/2 differentiation specifically to the cartilage lineage and at high yields. These conditions include high cell density micromass cultures, a purified mixture of osteoinductive-proteins (BP; Intermedics Orthopedics, Denver, CO), a serum substitute, 50 micrograms/ml ascorbic acid, and 10 mM beta-glycerophosphate. The cartilagenous fate was confirmed by 1) histological detection of sulfated proteoglycans, 2) electron microscopic detection of proteoglycan and rounded cells separated by extracellular matrix containing short, disorganized collagen fibrils, 3) morphological detection of chondrocytes surrounded by a territorial matrix and encompassed within a distinct perichondrium, and 4) immunocytochemical detection of type II collagen and link protein. After 4 weeks in culture, mature although unmineralized cartilage was observed, as indicated by hypertrophic morphology, immunocytochemical detection of osteocalcin, and histological detection of lacunae. These conditions promote overt chondrogenesis for most of the treated cells and preclude lineage determination to the fat, muscle, and bone lineage, as assayed by electron microscopy and histomorphology. The faithful recapitulation of cartilage differentiation that we have established in vitro provides a versatile alternative to the use of chondrocyte and limb bud explant cultures. We propose this as a model system to study the factors that regulate commitment to the chondrogenic lineage, exclusion to related mesengenic pathways, and maturation during chondrogenesis.
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Affiliation(s)
- B L Atkinson
- Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA
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Gordon DF, Wagner J, Atkinson BL, Chiono M, Berry R, Sikela J, Gutierrez-Hartmann A. Human Cart-1: structural organization, chromosomal localization, and functional analysis of a cartilage-specific homeodomain cDNA. DNA Cell Biol 1996; 15:531-41. [PMID: 8756334 DOI: 10.1089/dna.1996.15.531] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [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: 02/02/2023] Open
Abstract
Homeoproteins control cell fates during development, specifying pattern formation and the ontogeny of specific tissues and organs in embryogenesis. Cart-1 cDNA was recently cloned from a rat chondrosarcoma tumor and it encodes a protein containing a paired-like homeodomain that is selectively expressed in cartilage during early chondrocyte differentiation. Here we report the molecular cloning of the human Cart-1 cDNA from a HeLa cervical carcinoma cDNA library. The human Cart-1 cDNA sequence is 88% identical and the deduced amino acid sequence is 95% identical to the rat sequence, indicating that Cart-1 structure is highly conserved. Northern and reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed Cart-1 mRNA expression in HeLa cervical carcinoma cells and human cervical tissue, but Cart-1 mRNA was not detected in GH3 rat pituitary cells and murine 10T1/2 one-half fibroblast cells. The Cart-1 gene was localized to human chromosome 12 and regionally mapped to the 12q21.3-q22 by PCR analysis of rodent-X-human somatic cell hybrid DNA and the CEPH megabase-insert YAC DNA pools, respectively. The Holt-Oram syndrome, characterized by upper limb and atrial septal dysplasias, also maps to the 12q21.3-q22 region. Cotransfection studies show that Cart-1 inhibits the rat prolactin promoter and that this repression is mediated by footprint II, an AT-rich element that functions as an inhibitory site of prolactin gene expression in nonpituitary cells and which was used to clone Cart-1. Taken together, these data indicate that Cart-1 may also influence cervix development, identify a putative DNA binding site for Cart-1, and, begin to define its functional role as modulator of gene expression.
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Affiliation(s)
- D F Gordon
- Department of Medicine, University of Colorado, Health Sciences Center, Denver 80262, USA
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Atkinson BL, Ryan ME, Benedict JJ, Huffer WE, Gutierrez-Hartmann A. Elucidation of homeoprotein Cart-1 function during in vitro chondrogenesis of C3H10T1/2 micromass cultures. Ann N Y Acad Sci 1996; 785:206-8. [PMID: 8702130 DOI: 10.1111/j.1749-6632.1996.tb56262.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- B L Atkinson
- Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA
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Jensen KB, Atkinson BL, Willis MC, Koch TH, Gold L. Using in vitro selection to direct the covalent attachment of human immunodeficiency virus type 1 Rev protein to high-affinity RNA ligands. Proc Natl Acad Sci U S A 1995; 92:12220-4. [PMID: 8618873 PMCID: PMC40328 DOI: 10.1073/pnas.92.26.12220] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.5] [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: 01/31/2023] Open
Abstract
We have used an in vitro selection procedure called crosslinking SELEX (SELEX = systematic evolution of ligands by exponential enrichment) to identify RNA sequences that bind with high affinity and crosslink to the Rev protein from human immunodeficiency virus type 1 (HIV-1). A randomized RNA library substituted with the photoreactive chromophore 5-iodouracil was irradiated with monochromatic UV light in the presence of Rev. Those sequences with the ability to photocrosslink to Rev were partitioned from the rest of the RNA pool, amplified, and used for the next round of selection. Rounds of photocrosslinking selection were alternated with rounds of selection for RNA sequences with high affinity to Rev. This iterative, dual-selection method yielded RNA molecules with subnanomolar dissociation constants and high efficiency photocrosslinking to Rev. Some of the RNA molecules isolated by this procedure form a stable complex with Rev that is resistant to denaturing gel electrophoresis in the absence of UV irradiation. In vitro selection of nucleic acids by using modified nucleotides allows the isolation of nucleic acid molecules with potentially limitless chemical capacities to covalently attack a target molecule.
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Affiliation(s)
- K B Jensen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309, USA
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Atkinson BL. What of intensive care? Intensive Crit Care Nurs 1995; 11:59. [PMID: 7772955 DOI: 10.1016/s0964-3397(95)82014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Abstract
The lambdoid bacteriophage regulate gene expression by suppressing transcription terminators. Although similar in sequence to lambda, HK022 lacks an analogue to the lambda N antitermination gene and a distinct nutR sequence. To define the HK022 antitermination system, we plated the phage on Escherichia coli nus mutants that inhibit lambda N function. Only rpoB60 (also called nusC60) blocked HK022 lytic growth. Analyses of HK022-lambda hybrid phage suggested that a HK022 function analogous to lambda Q was inhibited by rpoB60. This result was confirmed with pR'-tR'-galK fusions. HK022 Q-protein suppressed tR' in wild-type but not in rpoB60 mutants. The lambda Q-protein, although inhibited by rpoB60, was more active than the HK022 analogue. A single amino acid difference between the two Q-proteins accounts for the phenotype. Changing the penultimate residue of HK022 Q from alanine to the lambda threonine generated a phage that could propagate on rpoB60 hosts. Host and phage mutations that permitted HK022 growth in rpoB60 strains were characterized. The bacterial suppressors were located in the Escherichia coli nusB gene. The phage suppressors represented recessive mutations in a HK022 b-region sequence encoding an open reading frame of 73 codons.
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Affiliation(s)
- B L Atkinson
- Institute of Cancer Research, Columbia University, College of Physicians and Surgeons, New York, NY 10032
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Abstract
The nun gene product of the lambdoid coliphage HK022 provokes premature transcription termination at, or near, the phage lambda nut sites. Termination by Nun and antitermination by lambda N protein both require the nut sites and Escherichia coli NusA, NusB and NusE proteins. To characterize further the host requirements for Nun termination, we selected host mutations that blocked termination at lambda nutR. In addition to mutations in nusA, nusB and nusE, we obtained mutations in rpoC, encoding the RNA polymerase beta' subunit. The nusA and rpoC mutations suppressed Nun termination but not antitermination by lambda N function. The mutations antagonized Nun only at lambda nutR; termination at lambda nutL occurred in all the mutant strains. Thus, nutL is not functionally equivalent to nutR. We conclude that the host requirements for Nun termination overlap but are not identical with those for N antitermination, and, in particular, that the beta' subunit of RNP may be Nun-specific.
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Affiliation(s)
- R Robledo
- Institute of Cancer Research, Columbia University College of Physicians and Surgeons, New York, NY 10032
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Abstract
The parasitic protozoan Leishmania major differentiates in vitro, from the insect-adapted promastigote to the mammalian infective amastigote, in response to a temperature shift from 25 degrees C to 37 degrees C. We studied the genes encoding 70 kilodalton heat shock proteins (hsp 70 genes) in Leishmania substocks, which vary in their capability to differentiate. In total, four hsp 70 genes are arranged in tandem with intergenic regions of about 380 bp. These hsp 70 genes are 89% conserved at the aminoacid level when compared to the T. brucei hsp 70 genes. The expression of these four hsp 70 genes is increased, in vitro and in vivo, in response to a temperature shift from 25 degrees C to 37 degrees C. The parasite thus indeed responds to the transfer between hosts like it responds to a heat shock. In contrast, the high rate of transcription of a fifth identical hsp 70 gene, located at a separate locus, is unaffected by temperature shifts. The hsp 70 mRNAs have mini-exons trans-spliced onto their 5' ends and share unusually long (1000 nt) 3' untranslated extensions containing repetitive sequences. It is unclear whether or not the intergenic regions of the L. major hsp 70 genes function in transcription initiation and/or whether transcription results in the generation of polycistronic pre-mRNAs. Since each of the hsp 70 genes that we identified is expressed normally in an L. major substock that lost the capability to differentiate in response to an in vitro temperature shift, the inability to differentiate does not result from a general defect in the temperature-dependent control of transcription.
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Affiliation(s)
- M G Lee
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York 10032
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Atkinson BL. Management of the intensive care unit. Nursing 1987; 3:584-9. [PMID: 3646551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Atkinson BL. The intensive care unit. Nursing 1987; 3:547-51. [PMID: 3646545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Millham J, Chilcutt J, Atkinson BL. Comparability of naturalistic and controlled observation assessment of adaptive behavior. Am J Ment Defic 1978; 83:52-9. [PMID: 677179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The comparability of retrospective naturalistic and controlled observation assessment of adaptive behavior was evaluated. The number, degree, and direction of discrepancies were evaluated with respect to level of retardation of the client, rater differences, behavior domain sampled, and prior observational base for the ratings. Generally poor comparability between the procedures was found and questions were raised concerning the types of generalizability that can be made from adaptive behavior assessment obtained under the two procedures.
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