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Spering C, Moerer O, White TW, Lehmann W. [Surgical reconstruction of chest wall instability : Indications, contraindications and timing of surgery]. Unfallchirurgie (Heidelb) 2024; 127:171-179. [PMID: 38214732 DOI: 10.1007/s00113-023-01400-2] [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] [Subscribe] [Scholar Register] [Accepted: 11/30/2023] [Indexed: 01/13/2024]
Abstract
The impact of energy on the thorax can lead to serial rib fractures, sternal fractures, the combination of both and to injury of intrathoracic organs depending on the type, localization and intensity. Sometimes this results in chest wall instability with severe impairment of the respiratory mechanics. In the last decade the importance of surgical chest wall reconstruction in cases of chest wall instability has greatly increased. The evidence for a surgical approach has in the meantime been supported by prospective randomized multicenter studies, multiple retrospective data analyses and meta-analyses based on these studies, including a Cochrane review. The assessment of form and severity of the trauma and the degree of impairment of the respiratory mechanism are the basis for a structured decision on an extended conservative or surgical reconstructive strategy as well as the timing, type and extent of the operation. The morbidity (rate of pneumonia, duration of intensive care unit stay and mechanical ventilation) and fatality can be reduced by a timely surgery within 72 h after trauma. In this article the already established and evidence-based algorithms for surgical chest wall reconstruction are discussed in the context of the current evidence.
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Affiliation(s)
- Christopher Spering
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, Universitätsmedizin Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Deutschland.
| | - Onnen Moerer
- Klinik für Anästhesiologie, Universitätsmedizin Göttingen, Göttingen, Deutschland
| | - Thomas W White
- Department of Surgery, Intermountain Medical Center, Murray, UT, USA
| | - Wolfgang Lehmann
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, Universitätsmedizin Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Deutschland
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2
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Lie AL, Pan X, Vaghefi E, White TW, Donaldson PJ. Alterations in Lens Free Water Distribution Are Associated with Shape Deformation in Accommodation. Ophthalmol Sci 2024; 4:100404. [PMID: 38027421 PMCID: PMC10654372 DOI: 10.1016/j.xops.2023.100404] [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] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/05/2023] [Accepted: 09/22/2023] [Indexed: 12/01/2023]
Abstract
Objective To investigate whether a redistribution of water within the crystalline lens is associated with the shape deformation that occurs during accommodation. Design Observational, cross sectional study. Subjects Eleven young adults without presbyopia (aged 18-39 years) and 9 middle-aged adults with presbyopia (aged 40-55 years). Methods Magnetic resonance imaging (MRI) scans of the lens were acquired on a 3 Tesla clinical MRI scanner, without and with the presentation of a 3 Diopter accommodative stimulus. The MRIs were postprocessed using established methods to extract the geometric dimensions and spatial maps of water distribution of the lens. Main Outcome Measures Accommodative changes in the full 3-dimensional description of lens shape, the lens total-water distribution profile, and the lens free-water distribution profile. Results Viewing of an accommodative stimulus by young subjects elicited an elastic shape deformation of the lens consistent with accommodation that was associated with an elevated, smoother free-water distribution, primarily in the anterior region of the lens. In contrast, viewing of an accommodative stimulus by presbyopic subjects produced an atypical shape deformation of the lens that was instead associated with a lowered free-water distribution, primarily in the anterior region of the lens. No discernible changes to the lens total-water distribution were observed in response to the accommodative stimulus in either subject cohort. Conclusions The present study suggests that protein-mediated alterations in the free-water distribution of the anterior region of the lens influence the shape deformation in accommodation, presenting pharmacological modulation of free-water distribution as an attractive novel approach for treating presbyopia. Financial Disclosures The authors have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Alyssa L. Lie
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Xingzheng Pan
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Thomas W. White
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, New York
| | - Paul J. Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Forrester JD, Bauman ZM, Cole PA, Edwards JG, Knight AW, LaRoque M, Raffa T, White TW, Kartiko S. Chest Wall Injury Society recommendation for surgical stabilization of nonunited rib fractures to decrease pain, reduce opiate use, and improve patient reported outcomes in patients with rib fracture nonunion after trauma. J Trauma Acute Care Surg 2023; 95:943-950. [PMID: 37728432 DOI: 10.1097/ta.0000000000004083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 09/21/2023]
Abstract
BACKGROUND Rib fractures are common injuries which can be associated with acute pain and chronic disability. While most rib fractures ultimately go on to achieve bony union, a subset of patients may go on to develop non-union. Management of these nonunited rib fractures can be challenging and variability in management exists. METHODS The Chest Wall Injury Society's Publication Committee convened to develop recommendations for use of surgical stabilization of nonunited rib fractures (SSNURF) to treat traumatic rib fracture nonunions. PubMed, Embase, and the Cochrane database were searched for pertinent studies. Using a process of iterative consensus, all committee members voted to accept or reject the recommendation. RESULTS No identified studies compared SSNURF to alternative therapy and the overall quality of the body of evidence was rated as low. Risk of bias was identified in all studies. Despite these limitations, there is lower-quality evidence suggesting that SSNURF may be beneficial for decreasing pain, reducing opiate use, and improving patient reported outcomes among patients with symptomatic rib nonunion. However, these benefits should be balanced against risk of symptomatic hardware failure and infection. CONCLUSION This guideline document summarizes the current CWIS recommendations regarding use of SSNURF for management of rib nonunion. LEVEL OF EVIDENCE Therapeutic/Care Management; Level IV.
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Affiliation(s)
- Joseph D Forrester
- From the Division of General Surgery, Department of Surgery (J.D.F., A.K.), Stanford University, Stanford, California; Division of Acute Care Surgery (Z.M.B.), University of Nebraska Medical Center, Omaha, Nebraska; HealthPartners Orthopaedics and Sports Medicine (P.A.C.), Bloomington, Minnesota; Department of Orthopaedic Surgery (P.A.C., M.L.), University of Minnesota, Minneapolis, Minnesota; Department of Orthopaedic Surgery (P.A.C.), Regions Hospital, Saint Paul, Minnesota; Sheffield Teaching Hospitals NHS Trust (J.G.E.), Sheffield, United Kingdom; and Center for Trauma and Critical Care (T.R., T.W.W.), Department of Surgery (T.R., S.K.), George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
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Desrochers R, Liu YJ, Whitbeck SS, Kartiko S, White TW, Doben AR. Recent Advances in Rib Plating. Surg Technol Int 2023; 43:sti43/1726. [PMID: 38038173 DOI: 10.52198/23.sti.43.os1726] [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: 01/27/2024]
Abstract
Rib fractures are a common injury in blunt trauma and are associated with high morbidity and mortality. Recent advances in surgical stabilization of rib fractures (SSRF) have led to better patient outcomes for those with highly unstable complex rib fractures, as well as those with less severe injuries. This result has been due in part to the expansion of indications for repair, as well as the development of new hardware systems to address a variety of fracture patterns and injuries. This joint advancement of operator techniques, outcomes research, and industry development has brought SSRF to the forefront of rib fracture management and challenged non-operative paradigms. The future of repair is now shifting focus, as surgeons develop minimally invasive approaches and challenge manufacturers to develop new systems, instruments, and materials to address increasingly complex fracture patterns. These expansions promise to make SSRF an increasingly effective form of management for traumatic rib fractures.
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Affiliation(s)
- Ryan Desrochers
- Saint Francis Hospital, Division of Acute Care Surgery, Hartford, CT
| | - Yuen-Joyce Liu
- Saint Francis Hospital, Division of Acute Care Surgery, Hartford, CT
| | | | - Susan Kartiko
- The George Washington University SMHS, Department of Surgery, Washington, DC
| | | | - Andrew R Doben
- Saint Francis Hospital, Division of Acute Care Surgery, Hartford, CT
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Eriksson EA, Waite A, Whitbeck SS, Bach JA, Bauman ZM, Cavlovic L, Dale K, DeVoe WB, Doben AR, Edwards JG, Forrester JD, Kaye AJ, Green J, Hsu J, Hufford A, Janowak C, Kartiko S, Moore EE, Patel B, Pieracci F, Sarani B, Schubl SD, Semon G, Thomas BW, Tung J, Van Lieshout EMM, White TW, Wijffels MME, Wullschleger ME. An initiative to assess and improve the resources and patient care processes used among Chest Wall Injury Society collaborative centers (CWIS-CC2). J Trauma Acute Care Surg 2023:01586154-990000000-00535. [PMID: 37889926 DOI: 10.1097/ta.0000000000004158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Abstract
BACKGROUND Over the last two decades, the acute management of rib fractures has changed significantly. In 2021, the Chest Wall injury Society (CWIS) began recognizing centers who epitomize their mission as CWIS Collaborative Centers (CWIS-CC). The primary aim of this study was to determine the resources, surgical expertise, access to care, and institutional support that are present among centers. METHODS A survey was performed including all CWIS-CC evaluating the resources available at their hospital for the treatment of patients with chest wall injury. Data about each Chest Wall Injury Center (CWIC) care process, availability of resources, institutional support, research support, and educational offerings were recorded. RESULTS Data was collected from 20 trauma centers resulting in an 80% response rate. These trauma centers were made up of 5 international and 15 US based trauma centers. Eighty percent (16/20) have dedicated care team members for the evaluation and management of rib fractures. Twenty-five percent (5/20) have a dedicated rib fracture service with a separate call schedule. Staffing for chest wall injury clinics consists of a multidisciplinary team: with attending surgeons in all clinics, 80%(8/10) with APPs and 70%(7/10) with care coordinators. Forty percent(8/20) of centers have dedicated rib fracture research support and 35%(7/20) have SSRF-related grants. Forty percent (8/20) of centers have marketing support and 30%(8/20) have a web page support to bring awareness to their center. At these trauma centers, a median of 4(1-9) surgeons perform surgical stabilization of rib fractures (SSRF). In the majority of trauma centers the trauma surgeons perform SSRF. CONCLUSIONS Considerable similarities and differences exist within these CWIS collaborative centers. These differences in resources are hypothesis generating in determining the optimal CWIC. These findings may generate several patient care and team process questions to optimize patient care, patient experience, provider satisfaction, research productivity, education, and outreach. LEVEL OF EVIDENCE IV Economic & Value-Based Evaluations.
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Affiliation(s)
| | - Amanda Waite
- Medical University of South Carolina, Department of Surgery
| | | | - John A Bach
- Riverside Methodist Hospital, Department of Surgery
| | | | | | - Kate Dale
- Gold Coast Health, Department of Surgery
| | | | - Andrew R Doben
- St Francis Hospital and Medical Center, Department of Surgery
| | - John G Edwards
- Sheffield Teaching Hospitals NHS Foundation, Department of Cardiothoracic Surgery
| | | | - Adam J Kaye
- Overland Park Regional Medical Center, Department of Surgery
| | | | - Jeremy Hsu
- Westmead Hospital University of Sydney, Department of Surgery
| | - Andrea Hufford
- Overland Park Regional Medical Center, Department of Surgery
| | | | - Susan Kartiko
- The George Washington University, Department of Surgery
| | | | | | | | - Babak Sarani
- The George Washington University, Department of Surgery
| | | | | | | | - Jamie Tung
- Stanford University, Department of Surgery
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Giannone AA, Sellitto C, Rosati B, McKinnon D, White TW. Single-Cell RNA Sequencing Analysis of the Early Postnatal Mouse Lens Epithelium. Invest Ophthalmol Vis Sci 2023; 64:37. [PMID: 37870847 PMCID: PMC10599162 DOI: 10.1167/iovs.64.13.37] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 08/14/2023] [Accepted: 10/06/2023] [Indexed: 10/24/2023] Open
Abstract
Purpose The lens epithelium maintains the overall health of the organ. We used single-cell RNA sequencing (scRNA-seq) technology to assess transcriptional heterogeneity between cells in the postnatal day 2 (P2) epithelium and identify distinct epithelial cell subtypes. Analysis of these data was used to better understand lens growth, differentiation, and homeostasis on P2. Methods scRNA-seq on P2 mouse lenses was performed using the 10x Genomics Chromium Single Cell 3' Kit (v3.1) and short-read Illumina sequencing. Sequence alignment and preprocessing of data were conducted using 10x Genomics Cell Ranger software. Seurat was employed for preprocessing, quality control, dimensionality reduction, and cell clustering, and Monocle was utilized for trajectory analysis to understand the developmental progression of the lens cells. CellChat and GO analyses were used to explore cell-cell communication networks and signaling interactions. Results Lens epithelial cells (LECs) were divided into seven subclusters, classified by specific gene markers. The expression of crystallin, cell-cycle, and metabolic genes was not uniform, indicating distinct functional roles of LECs. Trajectory analysis predicted a bifurcation of differentiating and cycling cells from an Igfbp5+ progenitor pool. We also identified heterogeneity in signaling molecules and pathways, suggesting that cycling and progenitor subclusters have prominent roles in coordinating crosstalk. Conclusions scRNA-seq corroborated many known markers of epithelial differentiation and proliferation while providing further insight into the pathways and genes directing these processes. Interestingly, we demonstrated that the developing epithelium can be divided into distinct subpopulations. These clusters reflect the transcriptionally diverse roles of the epithelium in proliferation, signaling, and maintenance.
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Affiliation(s)
- Adrienne A. Giannone
- Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook University, Stony Brook, New York, United States
| | - Caterina Sellitto
- Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook University, Stony Brook, New York, United States
| | - Barbara Rosati
- Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook University, Stony Brook, New York, United States
- Veterans Affairs Medical Center, Northport, New York, United States
| | - David McKinnon
- Department of Neurobiology and Behavior, Stony Brook University School of Medicine, Stony Brook University, Stony Brook, New York, United States
| | - Thomas W. White
- Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook University, Stony Brook, New York, United States
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Pan X, Muir ER, Sellitto C, Wang K, Cheng C, Pierscionek B, Donaldson PJ, White TW. Age-Dependent Changes in the Water Content and Optical Power of the In Vivo Mouse Lens Revealed by Multi-Parametric MRI and Optical Modeling. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 37079314 PMCID: PMC10132318 DOI: 10.1167/iovs.64.4.24] [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: 01/10/2023] [Accepted: 03/31/2023] [Indexed: 04/21/2023] Open
Abstract
Purpose The purpose of this study was to utilize in vivo magnetic resonance imaging (MRI) and optical modeling to investigate how changes in water transport, lens curvature, and gradient refractive index (GRIN) alter the power of the mouse lens as a function of age. Methods Lenses of male C57BL/6 wild-type mice aged between 3 weeks and 12 months (N = 4 mice per age group) were imaged using a 7T MRI scanner. Measurements of lens shape and the distribution of T2 (water-bound protein ratios) and T1 (free water content) values were extracted from MRI images. T2 values were converted into the refractive index (n) using an age-corrected calibration equation to calculate the GRIN at different ages. GRIN maps and shape parameters were inputted into an optical model to determine ageing effects on lens power and spherical aberration. Results The mouse lens showed two growth phases. From 3 weeks to 3 months, T2 decreased, GRIN increased, and T1 decreased. This was accompanied by increased lens thickness, volume, and surface radii of curvatures. The refractive power of the lens also increased significantly, and a negative spherical aberration was developed and maintained. Between 6 and 12 months of age, all physiological, geometrical, and optical parameters remained constant, although the lens continued to grow. Conclusions In the first 3 months, the mouse lens power increased as a result of changes in shape and in the GRIN, the latter driven by the decreased water content of the lens nucleus. Further research into the mechanisms regulating this decrease in mouse lens water could improve our understanding of how lens power changes during emmetropization in the developing human lens.
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Affiliation(s)
- Xingzheng Pan
- Department of Physiology, School of Medical Sciences, New Zealand Eye Centre, University of Auckland, New Zealand
| | - Eric R. Muir
- Department of Radiology, School of Medicine, Stony Brook University, Stony Brook, New York, United States
| | - Caterina Sellitto
- Department of Physiology & Biophysics, School of Medicine, Stony Brook University, Stony Brook, New York, United States
| | - Kehao Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Engineering Medicine, Beihang University, Beijing, China
| | - Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, Indiana, United States
| | - Barbara Pierscionek
- Faculty of Health, Education, Medicine and Social Care, Medical Technology Research Centre, Anglia Ruskin University, Chelmsford Campus, United Kingdom
| | - Paul J. Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand Eye Centre, University of Auckland, New Zealand
| | - Thomas W. White
- Department of Physiology & Biophysics, School of Medicine, Stony Brook University, Stony Brook, New York, United States
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Zhou Y, Bennett TM, White TW, Shiels A. Charged multivesicular body protein 4b forms complexes with gap junction proteins during lens fiber cell differentiation. FASEB J 2023; 37:e22801. [PMID: 36880430 PMCID: PMC10101236 DOI: 10.1096/fj.202201368rr] [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: 08/19/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 03/08/2023]
Abstract
Charged multivesicular body protein 4b (CHMP4B) is a core sub-unit of the endosomal sorting complex required for transport III (ESCRT-III) machinery that serves myriad remodeling and scission processes of biological membranes. Mutation of the human CHMP4B gene underlies rare forms of early-onset lens opacities or cataracts, and CHMP4B is required for lens growth and differentiation in mice. Here, we determine the sub-cellular distribution of CHMP4B in the lens and uncover a novel association with gap junction alpha-3 protein (GJA3) or connexin 46 (Cx46) and GJA8 or Cx50. Immunofluorescence confocal microscopy revealed that CHMP4B localized to cell membranes of elongated fiber cells in the outer cortex of the lens-where large gap junction plaques begin to form-particularly, on the broad faces of these flattened hexagon-like cells in cross-section. Dual immunofluorescence imaging showed that CHMP4B co-localized with gap junction plaques containing Cx46 and/or Cx50. When combined with the in situ proximity ligation assay, immunofluorescence confocal imaging indicated that CHMP4B lay in close physical proximity to Cx46 and Cx50. In Cx46-knockout (Cx46-KO) lenses, CHMP4B-membrane distribution was similar to that of wild-type, whereas, in Cx50-KO lenses, CHMP4B localization to fiber cell membranes was lost. Immunoprecipitation and immunoblotting analyses revealed that CHMP4B formed complexes with Cx46 and Cx50 in vitro. Collectively, our data suggest that CHMP4B forms plasma membrane complexes, either directly and/or indirectly, with gap junction proteins Cx46 and Cx50 that are often associated with "ball-and-socket" double-membrane junctions during lens fiber cell differentiation.
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Affiliation(s)
- Yuefang Zhou
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas M. Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas W. White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
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Peres C, Sellitto C, Nardin C, Putti S, Orsini T, Di Pietro C, Marazziti D, Vitiello A, Calistri A, Rigamonti M, Scavizzi F, Raspa M, Zonta F, Yang G, White TW, Mammano F. Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice. EBioMedicine 2023; 89:104453. [PMID: 36736132 PMCID: PMC9926223 DOI: 10.1016/j.ebiom.2023.104453] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Keratitis ichthyosis deafness (KID) syndrome is a rare disorder caused by hemichannel (HC) activating gain-of-function mutations in the GJB2 gene encoding connexin (Cx) 26, for which there is no cure, or current treatments based upon the mechanism of disease causation. METHODS We applied Adeno Associated Virus (AAV) mediated mAb gene transfer (AAVmAb) to treat the epidermal features of KID syndrome with a well-characterized HC blocking antibody using male mice of a murine model that replicates the skin pathology of the human disease. FINDINGS We demonstrate that in vivo AAVmAb treatment significantly reduced the size and thickness of KID lesions, in addition to blocking activity of mutant HCs in the epidermis in vivo. We also show that AAVmAb treatment eliminated abnormal keratinocyte proliferation and enlarged cell size, decreased apoptosis, and restored the normal distribution of keratin expression. INTERPRETATION Our findings reinforce the critical role played by increased HC activity in the skin pathology associated with KID syndrome. They also underscore the clinical potential of anti-HC mAbs coupled with genetic based delivery systems for treating the underlying mechanistic basis of this disorder. Inhibition of HC activity is an ideal therapeutic target in KID syndrome, and the genetic delivery of mAbs targeted against mutant HCs could form the basis of new therapeutic interventions to treat this incurable disease. FUNDING Fondazione Telethon grant GGP19148 and University of Padova grant Prot. BIRD187130 to FM; Foundation for Ichthyosis and Related Skin Types (FIRST) and National Institutes of Health grant EY 026911 to TWW.
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Affiliation(s)
- Chiara Peres
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Caterina Sellitto
- Department of Physiology and Biophysics, Stony Brook University, T5-147, Basic Science Tower; Stony Brook, NY, 11794-8661, USA
| | - Chiara Nardin
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Sabrina Putti
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Tiziana Orsini
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Chiara Di Pietro
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Daniela Marazziti
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Adriana Vitiello
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | | | - Ferdinando Scavizzi
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Marcello Raspa
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Francesco Zonta
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, 201210, China
| | - Guang Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, 201210, China
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, T5-147, Basic Science Tower; Stony Brook, NY, 11794-8661, USA.
| | - Fabio Mammano
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy; Department of Physics and Astronomy "G. Galilei", University of Padova, 35131, Padova, Italy.
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10
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Sellitto C, Li L, White TW. Double Deletion of PI3K and PTEN Modifies Lens Postnatal Growth and Homeostasis. Cells 2022; 11:cells11172708. [PMID: 36078116 PMCID: PMC9455000 DOI: 10.3390/cells11172708] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/23/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022] Open
Abstract
We have previously shown that the conditional deletion of either the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), or its opposing phosphatase, phosphatase and tensin homolog (PTEN), had distinct effects on lens growth and homeostasis. The deletion of p110α reduced the levels of phosphorylated Akt and equatorial epithelial cell proliferation, and resulted in smaller transparent lenses in adult mice. The deletion of PTEN increased levels of phosphorylated Akt, altered lens sodium transport, and caused lens rupture and cataract. Here, we have generated conditional p110α/PTEN double-knockout mice, and evaluated epithelial cell proliferation and lens homeostasis. The double deletion of p110α and PTEN rescued the defect in lens size seen after the single knockout of p110α, but accelerated the lens rupture phenotype seen in PTEN single-knockout mice. Levels of phosphorylated Akt in double-knockout lenses were significantly higher than in wild-type lenses, but not as elevated as those reported for PTEN single-knockout lenses. These results showed that the double deletion of the p110α catalytic subunit of PI3K and its opposing phosphatase, PTEN, exacerbated the rupture defect seen in the single PTEN knockout and alleviated the growth defect observed in the single p110α knockout. Thus, the integrity of the PI3K signaling pathway was absolutely essential for proper lens homeostasis, but not for lens growth.
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Abstract
The transparency and refractive properties of the lens are maintained by the cellular physiology provided by an internal microcirculation system that utilizes spatial differences in ion channels, transporters and gap junctions to establish standing electrochemical and hydrostatic pressure gradients that drive the transport of ions, water and nutrients through this avascular tissue. Aging has negative effects on lens transport, degrading ion and water homeostasis, and producing changes in lens water content. This alters the properties of the lens, causing changes in optical quality and accommodative amplitude that initially result in presbyopia in middle age and ultimately manifest as cataract in the elderly. Recent advances have highlighted that the lens hydrostatic pressure gradient responds to tension transmitted to the lens through the Zonules of Zinn through a mechanism utilizing mechanosensitive channels, multiple sodium transporters respond to changes in hydrostatic pressure to restore equilibrium, and that connexin hemichannels and diverse intracellular signaling cascades play a critical role in these responses. The mechanistic insight gained from these studies has advanced our understanding of lens transport and how it responds and adapts to different inputs both from within the lens, and from surrounding ocular structures.
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Affiliation(s)
- Adrienne A Giannone
- Master of Science Program, Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Leping Li
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Caterina Sellitto
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Thomas W White
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, United States
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Sellitto C, Li L, White TW. Connexin hemichannel inhibition ameliorates epidermal pathology in a mouse model of keratitis ichthyosis deafness syndrome. Sci Rep 2021; 11:24118. [PMID: 34916582 PMCID: PMC8677806 DOI: 10.1038/s41598-021-03627-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 12/07/2021] [Indexed: 02/05/2023] Open
Abstract
AbstractMutations in five different genes encoding connexin channels cause eleven clinically defined human skin diseases. Keratitis ichthyosis deafness (KID) syndrome is caused by point mutations in the GJB2 gene encoding Connexin 26 (Cx26) which result in aberrant activation of connexin hemichannels. KID syndrome has no cure and is associated with bilateral hearing loss, blinding keratitis, palmoplantar keratoderma, ichthyosiform erythroderma and a high incidence of childhood mortality. Here, we have tested whether a topically applied hemichhanel inhibitor (flufenamic acid, FFA) could ameliorate the skin pathology associated with KID syndrome in a transgenic mouse model expressing the lethal Cx26-G45E mutation. We found that FFA blocked the hemichannel activity of Cx26-G45E in vitro, and substantially reduced epidermal pathology in vivo, compared to untreated, or vehicle treated control animals. FFA did not reduce the expression of mutant connexin hemichannel protein, and cessation of FFA treatment allowed disease progression to continue. These results suggested that aberrant hemichannel activity is a major driver of skin disease in KID syndrome, and that the inhibition of mutant hemichannel activity could provide an attractive target to develop novel therapeutic interventions to treat this incurable disease.
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Kay AB, Morris DS, Gardner S, Majercik S, White TW. Readmission for pleural space complications after chest wall injury: Who is at risk? J Trauma Acute Care Surg 2021; 91:981-987. [PMID: 34538827 DOI: 10.1097/ta.0000000000003408] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Little is known about patient characteristics predicting postdischarge pleural space complications (PDPSCs) after thoracic trauma. We sought to analyze the patient population who required unplanned hospital readmission for PDPSC. METHODS Retrospective review of adult patients admitted to a Level I Trauma Center with a chest Abbreviated Injury Scale (AIS) score of 2 or greater between January 2015 and August 2020. Those readmitted within 30 days of index hospitalization discharge for PDPSC were compared with those not readmitted. Demographics, injury characteristics, surgical procedures, imaging, and readmission data were retrieved. RESULTS Out of 17,192 trauma evaluations, 3,412 (19.8%) suffered a chest AIS score of 2 or greater injury and 155 experienced an unplanned 30-day hospital readmission. Of those, 49 (1.4%) were readmitted for the management of PDPSC (readmit PDPSC) and were compared with patients who were not readmitted (no readmit, n = 3,257). The readmit PDPSC group was significantly older age, heavier, comprised of fewer men, and suffered a higher mean chest AIS score. The readmit PDPSC group had a significantly higher incidence of rib fractures, flail chest, pneumothorax, hemothorax, scapula fractures, and a higher rate of tube thoracostomy placement during index admission. The discharge chest X-ray in the readmit PDPSC group demonstrated a pleural space abnormality in 36 (73%) of patients. Mean time to readmission was 10.2 (7.2) days, and hospital length of stay on readmission was 5.8 (3.7) days. Pleural effusion was the most common readmission diagnosis (44 [90%]), and 42 (86%) required tube thoracostomy. CONCLUSION We describe the subset of chest wall injury patients who require hospital readmission for PDPSC. Characteristics from index hospitalization associated with PDPSC include older age, female sex, heavier weight, presence of rib fractures, pleural space abnormality, scapular fracture, and chest tube placement. Further studies are needed to characterize this at-risk chest wall injury population, and to determine what interventions can facilitate outpatient management of postdischarge pleural space complications and mitigate readmission risk. LEVEL OF EVIDENCE Prognostic and epidemiologic, Level IV; Care management, Level V.
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Affiliation(s)
- Annika B Kay
- From the Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, Utah
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Lie AL, Pan X, White TW, Vaghefi E, Donaldson PJ. Age-Dependent Changes in Total and Free Water Content of In Vivo Human Lenses Measured by Magnetic Resonance Imaging. Invest Ophthalmol Vis Sci 2021; 62:33. [PMID: 34293079 PMCID: PMC8300047 DOI: 10.1167/iovs.62.9.33] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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] [Indexed: 01/01/2023] Open
Abstract
Purpose To use magnetic resonance imaging (MRI) to measure age-dependent changes in total and free water in human lenses in vivo. Methods Sixty-four healthy adults aged 18 to 86 years were recruited, fitted with a 32-channel head receiver coil, and placed in a 3 Tesla clinical MR scanner. Scans of the crystalline lens were obtained using a volumetric interpolated breath-hold examination sequence with dual flip angles, which were corrected for field inhomogeneity post-acquisition using a B1-map obtained using a turbo-FLASH sequence. The spatial distribution and content of corrected total (ρlens) and free (T1) water along the lens optical axis were extracted using custom-written code. Results Lens total water distribution and content did not change with age (all P > 0.05). In contrast to total water, a gradient in free water content that was highest in the periphery relative to the center was present in lenses across all ages. However, this initially parabolic free water gradient gradually developed an enhanced central plateau, as indicated by increasing profile shape parameter values (anterior: 0.067/y, P = 0.004; posterior: 0.050/y, P = 0.020) and central free water content (1.932 ms/y, P = 0.022) with age. Conclusions MRI can obtain repeatable total and free water measurements of in vivo human lenses. The observation that the lens steady-state free, but not total, water gradient is abolished with age raises the possibility that alterations in protein-water interactions are an underlying cause of the degradation in lens optics and overall vision observed with aging.
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Affiliation(s)
- Alyssa L Lie
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand.,Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, United States
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
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Pieracci FM, Schubl S, Gasparri M, Delaplain P, Kirsch J, Towe C, White TW, Whitbeck S, Doben AR. The Chest Wall Injury Society Recommendations for Reporting Studies of Surgical Stabilization of Rib Fractures. Injury 2021; 52:1241-1250. [PMID: 33795145 DOI: 10.1016/j.injury.2021.02.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 09/21/2020] [Revised: 01/20/2021] [Accepted: 02/12/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Publications investigating the efficacy of surgical stabilization of rib fractures (SSRF) have increased exponentially. However, there is currently no standardized reporting structure for these studies, rendering both comparisons and extrapolation problematic. METHODS A subject matter expert group was formed by the Chest Wall Injury Society. This group conducted a review of the SSRF investigational literature and identified variable reporting within several general categories of relevant parameters. A compliment of guidelines was then generated. RESULTS The reporting guidelines consist of 26 recommendations in the categories of: (1) study type, (2) patient and injury characteristics, (3) patient treatments, (4) outcomes, and (5) statistical considerations. CONCLUSION Our review identified inconsistencies in reporting within the investigational SSRF literature. In response to these inconsistencies, we propose a set of recommendations to standardize reporting of original investigations into the efficacy of SSRF.
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Affiliation(s)
- Fredric M Pieracci
- Department Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO.
| | - Sebastian Schubl
- Department of Surgery, University of California-Irvine, Irvine, CA
| | - Mario Gasparri
- Department of Surgery, Division of CT Surgery, Medical College of Wisconsin, Milwaukee, WI
| | | | - Jordan Kirsch
- Department of Surgery, Section of Acute and Critical Care Surgery, Barnes-Jewish Hospital/Washington University, St. Louis, MI
| | - Christopher Towe
- Department of CT Surgery, University Hospitals and Case Western Reserve University School of Medicine, Cleveland, OH
| | - Thomas W White
- Department of Surgery, Intermountain Medical Center, Murray, UT
| | | | - Andrew R Doben
- Department of Surgery, St. Francis Medical Center, Hartford, CT
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Delamere NA, Shahidullah M, Mathias RT, Gao J, Sun X, Sellitto C, White TW. Signaling Between TRPV1/TRPV4 and Intracellular Hydrostatic Pressure in the Mouse Lens. Invest Ophthalmol Vis Sci 2021; 61:58. [PMID: 32598448 PMCID: PMC7415899 DOI: 10.1167/iovs.61.6.58] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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] [Indexed: 11/24/2022] Open
Abstract
Purpose The lens uses feedback to maintain zero pressure in its surface cells. Positive pressures are detected by transient receptor potential vanilloid (TRPV4), which initiates a cascade that reduces surface cell osmolarity. The first step is opening of gap junction hemichannels. One purpose of the current study was to identify the connexin(s) in the hemichannels. Negative pressures are detected by TRPV1, which initiates a cascade that increases surface osmolarity. The increase in osmolarity was initially reported to be through inhibition of Na/K ATPase activity, but a recent study reported it was through stimulation of Na/K/2Cl (NKCC) cotransport. A second purpose of this study was to reconcile these two reports. Methods Intracellular hydrostatic pressures were measured using a microelectrode/manometer system. Lenses from TRPV1 or Cx50 null mice were studied. Specific inhibitors of Cx50 gap junction channels, NKCC, and Akt were used. Results Either knockout of Cx50 or blockade of Cx50 channels completely eliminated the response to positive surface pressures. Knockout of Cx50 also caused a positive drift in surface pressure. The short-term (∼20-minute) response to negative surface pressures was eliminated by blockade of NKCC, but a long-term (∼4-hour) response restored pressure to zero. Both short- and long-term responses were eliminated by knockout of TRPV1 or inhibition of Akt. Conclusions Hemichannels made from Cx50 are required for the response to positive surface pressures. Negative surface pressures first activate NKCC, but a backup system is inhibition of Na/K ATPase activity. Both responses are initiated by TRPV1 and go through PI3K/Akt before branching.
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Brink PR, Valiunas V, White TW. Lens Connexin Channels Show Differential Permeability to Signaling Molecules. Int J Mol Sci 2020; 21:ijms21186943. [PMID: 32971763 PMCID: PMC7555617 DOI: 10.3390/ijms21186943] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 12/12/2022] Open
Abstract
Gap junction channels mediate the direct intercellular passage of small ions as well as larger solutes such as second messengers. A family of proteins called connexins make up the subunits of gap junction channels in chordate animals. Each individual connexin forms channels that exhibit distinct permeability to molecules that influence cellular signaling, such as calcium ions, cyclic nucleotides, or inositol phosphates. In this review, we examine the permeability of connexin channels containing Cx43, Cx46, and Cx50 to signaling molecules and attempt to relate the observed differences in permeability to possible in vivo consequences that were revealed by studies of transgenic animals where these connexin genes have been manipulated. Taken together, these data suggest that differences in the permeability of individual connexin channels to larger solutes like 3',5'-cyclic adenosine monophosphate (cAMP) and inositol 1,4,5-trisphosphate (IP3) could play a role in regulating epithelial cell division, differentiation, and homeostasis in organs like the ocular lens.
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18
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Lie AL, Pan X, White TW, Donaldson PJ, Vaghefi E. Using the Lens Paradox to Optimize an In Vivo MRI-Based Optical Model of the Aging Human Crystalline Lens. Transl Vis Sci Technol 2020; 9:39. [PMID: 32855885 PMCID: PMC7422912 DOI: 10.1167/tvst.9.8.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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] [Received: 06/03/2020] [Accepted: 06/23/2020] [Indexed: 12/27/2022] Open
Abstract
Purpose To optimize our in vivo magnetic resonance imaging (MRI)-based optical model of the human crystalline lens, developed with a small group of young adults, for a larger cohort spanning a wider age range. Methods Subjective refraction and ocular biometry were measured in 57 healthy adults ages 18 to 86 years who were then scanned using 3T clinical magnetic resonance imaging (MRI) to obtain lens gradient of refractive index (GRIN) and geometry measurements. These parameters were combined with ocular biometric measurements to construct individualized Zemax eye models from which ocular refractive errors and lens powers were determined. Models were optimized by adding an age-dependent factor to the transverse relaxation time (T2)-refractive index (n) calibration to match model-calculated refractive errors with subjective refractions. Results In our subject cohort, subjective refraction shifted toward hyperopia by 0.029 diopter/year as the lens grew larger and developed flatter GRINs with advancing age. Without model optimization, lens powers did not reproduce this clinically observed decrease, the so-called lens paradox, instead increasing by 0.055 diopter/year. However, modifying the T2-n calibration by including an age-dependent factor reproduced the decrease in lens power associated with the lens paradox. Conclusions After accounting for age-related changes in lens physiology in the T2-n calibration, our model was capable of accurately measuring in vivo lens power across a wide age range. This study highlights the need for a better understanding of how age-dependent changes to the GRIN impact the refractive properties of the lens. Translational Relevance MRI is applied clinically to calculate the effect of age-related refractive index changes in the lens paradox.
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Affiliation(s)
- Alyssa L Lie
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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19
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Bruzzone R, White TW. Connexin hemichannel inhibition improves skin pathology in Clouston syndrome mice. EBioMedicine 2020; 57:102856. [PMID: 32629388 PMCID: PMC7334806 DOI: 10.1016/j.ebiom.2020.102856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 06/10/2020] [Indexed: 10/25/2022] Open
Affiliation(s)
- Roberto Bruzzone
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, School of Public Health, The University of Hong Kong, Hong Kong, SAR
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, United States.
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20
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Valiunas V, White TW. Connexin43 and connexin50 channels exhibit different permeability to the second messenger inositol triphosphate. Sci Rep 2020; 10:8744. [PMID: 32457413 PMCID: PMC7251084 DOI: 10.1038/s41598-020-65761-z] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/07/2020] [Indexed: 11/12/2022] Open
Abstract
Gap junction channels made of different connexins have distinct permeability to second messengers, which could affect many cell processes, including lens epithelial cell division. Here, we have compared the permeability of IP3 and Ca2+ through channels made from two connexins, Cx43 and Cx50, that are highly expressed in vertebrate lens epithelial cells. Solute transfer was measured while simultaneously monitoring junctional conductance via dual whole-cell/perforated patch clamp. HeLa cells expressing Cx43 or Cx50 were loaded with Fluo-8, and IP3 or Ca2+ were delivered via patch pipette to one cell of a pair, or to a monolayer while fluorescence intensity changes were recorded. Cx43 channels were permeable to IP3 and Ca2+. Conversely, Cx50 channels were impermeable to IP3, while exhibiting high permeation of Ca2+. Reduced Cx50 permeability to IP3 could play a role in regulating cell division and homeostasis in the lens.
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Affiliation(s)
- Virginijus Valiunas
- The Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Thomas W White
- The Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.
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21
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Muir ER, Pan X, Donaldson PJ, Vaghefi E, Jiang Z, Sellitto C, White TW. Multi-parametric MRI of the physiology and optics of the in-vivo mouse lens. Magn Reson Imaging 2020; 70:145-154. [PMID: 32380160 DOI: 10.1016/j.mri.2020.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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: 02/26/2020] [Revised: 03/30/2020] [Accepted: 04/19/2020] [Indexed: 02/07/2023]
Abstract
The optics of the ocular lens are determined by its geometry (shape and volume) and its inherent gradient of refractive index (water to protein ratio), which are in turn maintained by unique cellular physiology known as the lens internal microcirculation system. Previously, magnetic resonance imaging (MRI) has been used on ex vivo organ cultured bovine lenses to show that pharmacological perturbations to this microcirculation system disrupt ionic and fluid homeostasis and overall lens optics. In this study, we have optimised in vivo MRI protocols for use on wild-type and transgenic mouse models so that the effects of genetically perturbing the lens microcirculation system on lens properties can be studied. In vivo MRI protocols and post-analysis methods for studying the mouse lens were optimised and used to measure the lens geometry, diffusion, T1 and T2, as well as the refractive index (n) calculated from T2, in wild-type mice and the genetically modified Cx50KI46 mouse. In this animal line, gap junctional coupling in the lens is increased by knocking in the gap junction protein Cx46 into the Cx50 locus. Relative to wild-type mice, Cx50KI46 mice showed significantly reduced lens size and radius of curvature, increased T1 and T2 values, and decreased n in the lens nucleus, which was consistent with the developmental and functional changes characterised previously in this lens model. These proof of principle experiments show that in vivo MRI can be applied to transgenic mouse models to gain mechanistic insights into the relationship between lens physiology and optics, and in the future suggest that longitudinal studies can be performed to determine how this relationship is altered by age in mouse models of cataract.
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Affiliation(s)
- Eric R Muir
- Department of Radiology, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand; Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Zhao Jiang
- Department of Radiology, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Caterina Sellitto
- Department of Physiology & Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Thomas W White
- Department of Physiology & Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, USA.
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22
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Chen Y, Gao J, Li L, Sellitto C, Mathias RT, Donaldson PJ, White TW. The Ciliary Muscle and Zonules of Zinn Modulate Lens Intracellular Hydrostatic Pressure Through Transient Receptor Potential Vanilloid Channels. Invest Ophthalmol Vis Sci 2020; 60:4416-4424. [PMID: 31639828 PMCID: PMC6808041 DOI: 10.1167/iovs.19-27794] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [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] [Indexed: 11/29/2022] Open
Abstract
Purpose Lenses have an intracellular hydrostatic pressure gradient to drive fluid from central fiber cells to surface epithelial cells. Pressure is regulated by a feedback control system that relies on transient receptor potential vanilloid (TRPV)1 and TRPV4 channels. The ciliary muscle transmits tension to the lens through the zonules of Zinn. Here, we have examined if ciliary muscle tension influenced the lens intracellular hydrostatic pressure gradient. Methods We measured the ciliary body position and intracellular hydrostatic pressures in mouse lenses while pharmacologically causing relaxation or contraction of the ciliary muscle. We also used inhibitors of TRPV1 and TRPV4, in addition to phosphoinositide 3-kinase (PI3K) p110α knockout mice and immunostaining of phosphorylated protein kinase B (Akt), to determine how changes in ciliary muscle tension resulted in altered hydrostatic pressure. Results Ciliary muscle relaxation increased the distance between the ciliary body and the lens and caused a decrease in intracellular hydrostatic pressure that was dependent on intact zonules and could be blocked by inhibition of TRPV4. Ciliary contraction moved the ciliary body toward the lens and caused an increase in intracellular hydrostatic pressure and Akt phosphorylation that required intact zonules and was blocked by either inhibition of TRPV1 or genetic deletion of the p110α catalytic subunit of PI3K. Conclusions These results show that the hydrostatic pressure gradient within the lens was influenced by the tension exerted on the lens by the ciliary muscle through the zonules of Zinn. Modulation of the gradient of intracellular hydrostatic pressure in the lens could alter the water content, and the gradient of refractive index.
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Affiliation(s)
- Yadi Chen
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Junyuan Gao
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Leping Li
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Caterina Sellitto
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Richard T Mathias
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Thomas W White
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
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23
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Gu S, Biswas S, Rodriguez L, Li Z, Li Y, Riquelme MA, Shi W, Wang K, White TW, Reilly M, Lo WK, Jiang JX. Connexin 50 and AQP0 are Essential in Maintaining Organization and Integrity of Lens Fibers. Invest Ophthalmol Vis Sci 2020; 60:4021-4032. [PMID: 31560767 PMCID: PMC6779290 DOI: 10.1167/iovs.18-26270] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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] [Indexed: 01/22/2023] Open
Abstract
Purpose Connexins and aquaporins play essential roles in maintaining lens homeostasis and transparency and there is a close physical and functional relationship between these two proteins. Aquaporin 0 (AQP0), in addition to its role in water transport in the lens, acts as a cell-cell adhesion molecule. Recently, we showed a new role of connexin (Cx) 50 in mediating cell-cell adhesion. However, the cooperative roles of these two proteins in the lens in vivo have not been reported. Methods We generated an AQP0/Cx50 double knockout (dKO) mouse model. Light, fluorescence, transmission thin section, and freeze-fracture electron microscopy, as well as wheat germ agglutinin and phalloidin labeling were used to evaluate lens structure. Mechanical properties of lenses were determined by mechanical compression testing. Results DKO mice exhibited small eyes and lenses with severe cataracts, along with lens posterior defects, including posterior capsule rupture. The dKO mouse lenses had severe structural disruption associated with increased spaces between lens fiber cells when compared with wild-type lenses or lenses deficient in either Cx50 or AQP0. DKO mice also exhibited greater reduction in lens size compared with Cx50 KO mice. Gap-junction plaque size was greatly decreased in cortical fiber cells in dKO mice. Moreover, lens stiffness and elasticity were completely diminished, exhibiting a gelatinous texture in adult dKO mice. Conclusions This novel mouse model reveals that Cx50 and AQP0 play an important role in mediating cell-cell adhesion function in the lens fiber cells and their deficiency impairs lens fiber organization, integrity, mechanical properties, and lens development.
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Affiliation(s)
- Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Sondip Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Luis Rodriguez
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Zhen Li
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Yuting Li
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Wen Shi
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States.,The Second Xiangya Hospital, Central South University, Changsha, China
| | - Ke Wang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, United States
| | - Matthew Reilly
- Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus, Ohio, United States
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States
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Cocozzelli AG, White TW. Connexin 43 Mutations Lead to Increased Hemichannel Functionality in Skin Disease. Int J Mol Sci 2019; 20:ijms20246186. [PMID: 31817921 PMCID: PMC6940829 DOI: 10.3390/ijms20246186] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [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] [Received: 10/31/2019] [Revised: 11/29/2019] [Accepted: 12/04/2019] [Indexed: 12/22/2022] Open
Abstract
Gap junctional channels are specialized components of the cellular membrane that allow the intercellular passage of small metabolites, ions, and second messengers to maintain homeostasis. They are comprised of members of the connexin gene family that encode a wide array of proteins that are expressed in nearly every tissue type. Cx43 is perceived to be the most broadly expressed connexin in humans, with several genetic skin diseases being linked to Cx43 mutations specifically. These mutations, in large, produce a gain of functional hemichannels that contribute to the phenotypes of Erythrokeratoderma Variabilis et Progressiva (EKVP), Palmoplantar Keratodemra Congenital Alopecia-1 (PPKCA1), and others that produce large conductance and increased permselectivity in otherwise quiescent structures. Gaining functional hemichannels can have adverse effects in the skin, inducing apoptosis via Ca2+ overload or increased ATP permeability. Here, we review the link between Cx43 and skin disease. We aim to provide insight into the mechanisms regulating the normal and pathophysiological gating of these essential proteins, as well as address current therapeutic strategies. We also demonstrate that transient transfection of neuro-2a (N2a) cells with mutant Cx43 cDNA resulted in increased hemichannel activity compared to wild-type Cx43 and untransfected cells, which is consistent with other studies in the current literature.
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Lee MY, Wang HZ, White TW, Brooks T, Pittman A, Halai H, Petrova A, Xu D, Hart SL, Kinsler VA, Di WL. Allele-Specific Small Interfering RNA Corrects Aberrant Cellular Phenotype in Keratitis-Ichthyosis-Deafness Syndrome Keratinocytes. J Invest Dermatol 2019; 140:1035-1044.e7. [PMID: 31705875 DOI: 10.1016/j.jid.2019.09.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 08/16/2019] [Accepted: 09/17/2019] [Indexed: 11/29/2022]
Abstract
Keratitis-ichthyosis-deafness (KID) syndrome is a severe, untreatable condition characterized by ocular, auditory, and cutaneous abnormalities, with major complications of infection and skin cancer. Most cases of KID syndrome (86%) are caused by a heterozygous missense mutation (c.148G>A, p.D50N) in the GJB2 gene, encoding gap junction protein Cx26, which alters gating properties of Cx26 channels in a dominant manner. We hypothesized that a mutant allele-specific small interfering RNA could rescue the cellular phenotype in patient keratinocytes (KCs). A KID syndrome cell line (KID-KC) was established from primary patient KCs with a heterozygous p.D50N mutation. This cell line displayed impaired gap junction communication and hyperactive hemichannels, confirmed by dye transfer, patch clamp, and neurobiotin uptake assays. A human-murine chimeric skin graft model constructed with KID-KCs mimicked patient skin in vivo, further confirming the validity of these cells as a model. In vitro treatment with allele-specific small interfering RNA led to robust inhibition of the mutant GJB2 allele without altering expression of the wild-type allele. This corrected both gap junction and hemichannel activity. Notably, allele-specific small interfering RNA treatment caused only low-level off-target effects in KID-KCs, as detected by genome-wide RNA sequencing. Our data provide an important proof-of-concept and model system for the potential use of allele-specific small interfering RNA in treating KID syndrome and other dominant genetic conditions.
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Affiliation(s)
- Ming Yang Lee
- Infection, Immunity and Inflammation Programme/Immunobiology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Hong-Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Tony Brooks
- UCL Genomics, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Alan Pittman
- Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom; Genetics Research Centre, St George's, University of London, London, United Kingdom
| | - Heerni Halai
- Infection, Immunity and Inflammation Programme/Immunobiology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Anastasia Petrova
- Infection, Immunity and Inflammation Programme/Immunobiology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Diane Xu
- Infection, Immunity and Inflammation Programme/Immunobiology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Stephen L Hart
- Department of Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Veronica A Kinsler
- Department of Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, United Kingdom; Paediatric Dermatology, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Wei-Li Di
- Infection, Immunity and Inflammation Programme/Immunobiology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.
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Valiunas V, Brink PR, White TW. Lens Connexin Channels Have Differential Permeability to the Second Messenger cAMP. Invest Ophthalmol Vis Sci 2019; 60:3821-3829. [PMID: 31529078 PMCID: PMC6750889 DOI: 10.1167/iovs.19-27302] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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] [Received: 04/09/2019] [Accepted: 08/13/2019] [Indexed: 01/14/2023] Open
Abstract
Purpose Gap junction channels exhibit connexin specific biophysical properties, including the selective intercellular passage of larger solutes, such as second messengers. Here, we have examined the cyclic nucleotide permeability of the lens connexins, which could influence events like epithelial cell division and differentiation. Methods We compared the cAMP permeability through channels composed of Cx43, Cx46, or Cx50 using simultaneous measurements of junctional conductance and intercellular transfer. For cAMP detection, the recipient cells were transfected with a cAMP sensor gene, the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH). cAMP was introduced via patch pipette into the cell of the pair that did not express SpIH. SpIH-derived currents were recorded from the other cell of a pair that expressed SpIH. cAMP permeability was also directly visualized in transfected cells using a chemically modified fluorescent form of the molecule. Results cAMP transfer was observed for homotypic Cx43 channels over a wide range of junctional conductance. Homotypic Cx46 channels also transferred cAMP, but permeability was reduced compared with Cx43. In contrast, homotypic Cx50 channels exhibited extremely low permeability to cAMP, when compared with either Cx43, or Cx46. Conclusions These data show that channels made from Cx43 and Cx46 result in the intercellular delivery of cAMP in sufficient quantity to activate cyclic nucleotide-modulated channels. The data also suggest that the greatly reduced cAMP permeability of Cx50 channels could play a role in the regulation of cell division in the lens.
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Affiliation(s)
- Virginijus Valiunas
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Peter R. Brink
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Thomas W. White
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
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Pan X, Lie AL, White TW, Donaldson PJ, Vaghefi E. Development of an in vivo magnetic resonance imaging and computer modelling platform to investigate the physiological optics of the crystalline lens. Biomed Opt Express 2019; 10:4462-4478. [PMID: 31565502 PMCID: PMC6757483 DOI: 10.1364/boe.10.004462] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/07/2019] [Accepted: 07/12/2019] [Indexed: 05/11/2023]
Abstract
We have developed and validated in vivo magnetic resonance imaging (MRI) protocols to extract parameters (T2 and geometry) of the human lens that, combined with biometric measures of the eye and optical modelling, enable us to investigate the relative contributions made by the gradient of refractive index (GRIN) and the shape of the lens to the refractive properties of each subject tested. Seven young and healthy participants (mean age: 25.6 ± 3.6 years) underwent an ophthalmic examination, and two sessions of MRI scans using a 3 T clinical magnet. Our MRI protocols for studying lens physiological optics and geometrical measurements were repeatable and reliable, using both 1D (95% confidence interval (CI) for mean differences for exponents = [-2.1, 2.6]) and 2D analysis (anterior T2 CI for differences [-6.4, 8.1] ms; posterior T2 CI for differences [-6.4, 8.3] ms). The lens thickness measured from MRI showed good correlation with that measured with clinical 'gold standard' LenStar (mean differences = [-0.18, 0.2] mm). The predicted refractive errors from ZEMAX had reasonable agreements with participants' clinic records (mean differences = [-1.7, 1.2] D). Quantitative measurements of lens geometry and GRIN with our MRI technique showed high inter-day repeatability. Our clinical MRI technique also provides reliable measures of lens geometry that are comparable to optical biometry. Finally, our ZEMAX optical models produced accurate refractive error and lens power estimations.
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Affiliation(s)
- Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Alyssa L. Lie
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Thomas W. White
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Paul J. Donaldson
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
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Suen HC, White TW. Surgical stabilization of rib fractures. J Thorac Dis 2019; 11:S1022-S1023. [PMID: 31205757 DOI: 10.21037/jtd.2019.05.01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hon Chi Suen
- Honorary Consultant in Cardiothoracic Surgery, Hong Kong Sanatorium and Hospital, Hong Kong, China.
| | - Thomas W White
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT, USA.
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Youssefian L, Vahidnezhad H, Saeidian AH, Mahmoudi H, Karamzadeh R, Kariminejad A, Huang J, Li L, Jannace TF, Fortina P, Zeinali S, White TW, Uitto J. A novel autosomal recessive GJB2-associated disorder: Ichthyosis follicularis, bilateral severe sensorineural hearing loss, and punctate palmoplantar keratoderma. Hum Mutat 2018; 40:217-229. [PMID: 30431684 DOI: 10.1002/humu.23686] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 08/02/2018] [Revised: 10/26/2018] [Accepted: 10/30/2018] [Indexed: 11/07/2022]
Abstract
Ichthyosis follicularis, a distinct cutaneous entity reported in combination with atrichia, and photophobia has been associated with mutations in MBTPS2. We sought the genetic cause of a novel syndrome of ichthyosis follicularis, bilateral severe sensorineural hearing loss and punctate palmoplantar keratoderma in two families. We performed whole exome sequencing on three patients from two families. The pathogenicity and consequences of mutations were studied in the Xenopus oocyte expression system and by molecular modeling analysis. Compound heterozygous mutations in the GJB2 gene were discovered: a pathogenic c.526A>G; p.Asn176Asp, and a common frameshift mutation, c.35delG; p.Gly12Valfs*2. The p.Asn176Asp missense mutation was demonstrated to significantly reduce the cell-cell gap junction channel activity and increase the nonjunctional hemichannel activity in the Xenopus oocyte expression system. Molecular modeling analyses of the mutant Cx26 protein revealed significant changes in the structural characteristics and electrostatic potential of the Cx26, either in hemichannel or gap junction conformation. Thus, association of a new syndrome of an autosomal recessive disorder of ichthyosis follicularis, bilateral severe sensorineural hearing loss and punctate palmoplantar keratoderma with mutations in GJB2, expands the phenotypic spectrum of the GJB2-associated disorders. The findings attest to the complexity of the clinical consequences of different mutations in GJB2.
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Affiliation(s)
- Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
| | - Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
- Biotechnology Research Center, Department of Molecular Medicine, Pasteur Institute of Iran, Tehran, Iran
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
- Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
| | - Hamidreza Mahmoudi
- Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Razieh Karamzadeh
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | | | - Jianhe Huang
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Leping Li
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Thomas F Jannace
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Paolo Fortina
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Sirous Zeinali
- Biotechnology Research Center, Department of Molecular Medicine, Pasteur Institute of Iran, Tehran, Iran
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
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Sollender GE, White TW, Pieracci FM. Fracture of the Costal Cartilage: Presentation, Diagnosis, and Management. Ann Thorac Surg 2018; 107:e267-e268. [PMID: 30359588 DOI: 10.1016/j.athoracsur.2018.08.076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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] [Received: 07/24/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
Abstract
A 52-year-old woman sustained a fracture of the left 7th costal cartilage after a ski injury. She presented complaining of painful clicking over the area. Initial imaging studies were negative for fracture; however, 3-dimensional reconstruction of a chest computed tomography scan, formatted to costal cartilage, revealed the fracture. She was offered and underwent surgical fixation of the fracture with a plate and 4 screws using a biaxial, convergent construct. Postoperatively, her symptoms resolved. In this case report, we review the rationale for fixation of costal cartilage, including a summary of previous literature pertaining to this relatively rare thoracic injury.
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Affiliation(s)
- Grace E Sollender
- Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire.
| | - Thomas W White
- Department of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Salt Lake City, Utah
| | - Fredric M Pieracci
- Denver Health Medical Center, University of Colorado School of Medicine, Denver, Colorado
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Abstract
Inherited or acquired alterations in the structure and function of connexin proteins have long been associated with disease. In the present work, we review current knowledge on the role of connexins in diseases associated with the heart, nervous system, cochlea, and skin, as well as cancer and pleiotropic syndromes such as oculodentodigital dysplasia (ODDD). Although incomplete by virtue of space and the extent of the topic, this review emphasizes the fact that connexin function is not only associated with gap junction channel formation. As such, both canonical and noncanonical functions of connexins are fundamental components in the pathophysiology of multiple connexin related disorders, many of them highly debilitating and life threatening. Improved understanding of connexin biology has the potential to advance our understanding of mechanisms, diagnosis, and treatment of disease.
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Affiliation(s)
- Mario Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York 10016
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A5C1, Canada
| | - Christian C Naus
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Morten S Nielsen
- Department of Biological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Vytautas K Verselis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York 10461
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York 11790
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Kay AB, Majercik S, Sorensen J, Woller SC, Stevens SM, White TW, Morris DS, Baldwin M, Bledsoe JR. Weight-based enoxaparin dosing and deep vein thrombosis in hospitalized trauma patients: A double-blind, randomized, pilot study. Surgery 2018; 164:S0039-6060(18)30094-1. [PMID: 29699807 DOI: 10.1016/j.surg.2018.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/15/2018] [Accepted: 03/07/2018] [Indexed: 01/25/2023]
Abstract
BACKGROUND Venous thromboembolism is a cause of morbidity and mortality in trauma patients. Chemoprophylaxis with low-molecular-weight heparin at a standardized dose is recommended. Conventional chemoprophylaxis may be inadequate. We hypothesized that a weight-adjusted enoxaparin prophylaxis regimen would reduce the frequency of venous thromboembolism in hospitalized trauma patients and at 90-day follow-up. METHODS This prospective, randomized pilot study enrolled adult patients admitted to a level 1 trauma center between July 2013 and January 2015. Subjects were randomized to receive either standard (30 mg subcutaneously every 12 hours) or weight-based (0.5mg/kg subcutaneously every 12 hours) enoxaparin. Surveillance duplex ultrasound for lower extremity deep vein thrombosis was performed on hospital days 1, 3, and 7, and weekly thereafter. The primary outcome was deep vein thrombosis during hospitalization. Secondary outcomes included venous thromboembolism at 90 days and significant bleeding events. RESULTS Two hundred thirty-four (124 standard, 110 weight-based) subjects were enrolled. There was no difference between standard and weight-based regarding age, body mass index, percentage female gender, injury severity score, or percentage that had surgery. There was a trend toward less in-hospital deep vein thrombosis in weight-based (12 [9.7%] standard vs 4 [3.6%] weight-based, P = .075). At 90 days, there was no difference in venous thromboembolism (12 [9.7%] standard vs 6 [5.5%] weight-based, P =.34). There was 1 bleeding event, which occurred in a standard subject. CONCLUSION Weight-based enoxaparin dosing for venous thromboembolism chemoprophylaxis in trauma patients may provide better protection against venous thromboembolism than standard. A definitive study is necessary to determine whether weight-based dosing is superior to standard.
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Affiliation(s)
- Annika Bickford Kay
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT
| | - Sarah Majercik
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT.
| | - Jeffrey Sorensen
- Division of Pulmonary and Critical Care Medicine, Intermountain Medical Center, Murray, UT
| | - Scott C Woller
- Department of Internal Medicine, Intermountain Medical Center, Murray, UT; Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT
| | - Scott M Stevens
- Department of Internal Medicine, Intermountain Medical Center, Murray, UT; Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT
| | - Thomas W White
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT
| | - David S Morris
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT
| | - Margaret Baldwin
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, Murray, UT
| | - Joseph R Bledsoe
- Department of Emergency Medicine, Intermountain Medical Center, Murray, UT
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Abstract
Blunt trauma to the chest wall and rib fractures are remarkably frequent and are the basis of considerable morbidity and possible mortality. Surgical remedies for highly displaced rib fractures, especially in cases of flail chest, have been undertaken intermittently for more than 50 years. Rib-specific plating systems have started to be used in the last 10 years. These have ushered in the modern era of rib repair with chest wall stabilization (CWS) techniques that are safer, easier to perform, and more efficient. Recent consensus statements have sought to define the indications and contraindications, as well as the when, the how, and the technical details of CWS. Repair should be considered for patients who have three or more displaced rib fractures or a flail chest, whether or not mechanical ventilation is required. Additional candidates include patients who fail non-operative management irrespective of fracture pattern and those with rib fractures who need thoracic procedures for other reasons. Traditionally, unstable spine fracture and severe traumatic brain injury are definite contraindications. Pulmonary contusion's role in the decision to perform CWS remains controversial. A range of rib-specific plating systems are now commercially available.
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Affiliation(s)
| | - Thomas W White
- Trauma and Surgical Critical Care, Intermountain Medical Center, Salt Lake City, Utah, USA
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Hu Z, Shi W, Riquelme MA, Shi Q, Biswas S, Lo WK, White TW, Gu S, Jiang JX. Connexin 50 Functions as an Adhesive Molecule and Promotes Lens Cell Differentiation. Sci Rep 2017; 7:5298. [PMID: 28706245 PMCID: PMC5509658 DOI: 10.1038/s41598-017-05647-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [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: 11/02/2016] [Accepted: 06/01/2017] [Indexed: 11/25/2022] Open
Abstract
Connexins play essential roles in lens homeostasis and development. Here, we identified a new role for Cx50 that mediates cell-cell adhesion function. Cx50 enhanced the adhesive capability of AQP0. Interestingly, the expression of Cx50 alone promoted cell adhesion at a comparable level to AQP0; however, this cell adhesive function was not observed with other lens connexins, Cx43 and Cx46. Moreover, the adhesive property occurred in both homotypic with Cx50 expressed in both pairing cells and heterotypic with Cx50 in only one pairing cell, and this function appears to be unrelated to its role in forming gap junction channels. Cx50 KO lenses exhibited increased intercellular spaces between lens fiber cells. The second extracellular loop domain (E2) is primarily responsible for this adhesive function. Treatment with a fusion protein containing E2 domain inhibited cell adhesion. Furthermore, disruption of cell adhesion by the E2 domains impaired primary lens cell differentiation. Five critical amino acid residues in the E2 domain primarily are involved in cell adhesive function as well as lens epithelial-fiber differentiation. Together, these results suggest that in addition to forming gap junction channels, Cx50 acts as an adhesive molecule that is critical in maintaining lens fiber integrity and epithelial-fiber differentiation.
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Affiliation(s)
- Zhengping Hu
- Departments of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wen Shi
- Departments of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Manuel A Riquelme
- Departments of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Qian Shi
- Departments of Physiology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Sondip Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Sumin Gu
- Departments of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Departments of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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Sellitto C, Li L, Vaghefi E, Donaldson PJ, Lin RZ, White TW. The Phosphoinosotide 3-Kinase Catalytic Subunit p110α is Required for Normal Lens Growth. Invest Ophthalmol Vis Sci 2017; 57:3145-51. [PMID: 27304846 PMCID: PMC4928694 DOI: 10.1167/iovs.16-19607] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Signal transduction pathways influence lens growth, but little is known about the role(s) of the class 1A phosphoinositide 3-kinases (PI3Ks). To further investigate how signaling regulates lens growth, we generated and characterized mice in which the p110α and p110β catalytic subunits of PI3K were conditionally deleted in the mouse lens. Methods Floxed alleles of the catalytic subunits of PI3K were conditionally deleted in the lens by using MLR10-cre transgenic mice. Lenses of age-matched animals were dissected and photographed. Postnatal lenses were fixed, paraffin embedded, sectioned, and stained with hematoxylin-eosin. Cell proliferation was quantified by labeling S-phase cells in intact lenses with 5-ethynyl-2′-deoxyuridine. Protein kinase B (AKT) activation was examined by Western blotting. Results Lens-specific deletion of p110α resulted in a significant reduction of eye and lens size, without compromising lens clarity. Conditional knockout of p110β had no effect on lens size or clarity, and deletion of both the p110α and p110β subunits resulted in a phenotype that resembled the p110α single-knockout phenotype. Levels of activated AKT were decreased more in p110α- than in p110β-deficient lenses. A significant reduction in proliferating cells in the germinative zone was observed on postnatal day 0 in p110α knockout mice, which was temporally correlated with decreased lens volume. Conclusions These data suggest that the class 1A PI3K signaling pathway plays an important role in the regulation of lens size by influencing the extent and spatial location of cell proliferation in the perinatal period.
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Affiliation(s)
- Caterina Sellitto
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
| | - Leping Li
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Richard Z Lin
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States 4Medical Service, Department of Veterans Affairs Medical Center, Northport, New York, United States
| | - Thomas W White
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
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Srinivas M, Verselis VK, White TW. Human diseases associated with connexin mutations. Biochim Biophys Acta Biomembr 2017; 1860:192-201. [PMID: 28457858 DOI: 10.1016/j.bbamem.2017.04.024] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 01/11/2023]
Abstract
Gap junctions and hemichannels comprised of connexins impact many cellular processes. Significant advances in our understanding of the functional role of these channels have been made by the identification of a host of genetic diseases caused by connexin mutations. Prominent features of connexin disorders are the inability of other connexins expressed in the same cell type to compensate for the mutated one, and the ability of connexin mutants to dominantly influence the activity of other wild-type connexins. Functional studies have begun to identify some of the underlying mechanisms whereby connexin channel mutation contributes to the disease state. Detailed mechanistic understanding of these functional differences will help to facilitate new pathophysiology driven therapies for the diverse array of connexin genetic disorders. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Miduturu Srinivas
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, NY 10036, USA
| | - Vytas K Verselis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA.
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Valiunas V, Valiuniene L, Brink PR, White TW. Comparison of Second Messenger Permeabilities through Gap Junction Channels Formed by CX43 and CX50. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.2976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Gao J, Sun X, White TW, Delamere NA, Mathias RT. Feedback Regulation of Intracellular Hydrostatic Pressure in Surface Cells of the Lens. Biophys J 2016; 109:1830-9. [PMID: 26536260 DOI: 10.1016/j.bpj.2015.09.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 09/08/2015] [Accepted: 09/16/2015] [Indexed: 10/22/2022] Open
Abstract
In wild-type lenses from various species, an intracellular hydrostatic pressure gradient goes from ∼340 mmHg in central fiber cells to 0 mmHg in surface cells. This gradient drives a center-to-surface flow of intracellular fluid. In lenses in which gap-junction coupling is increased, the central pressure is lower, whereas if gap-junction coupling is reduced, the central pressure is higher but surface pressure is always zero. Recently, we found that surface cell pressure was elevated in PTEN null lenses. This suggested disruption of a feedback control system that normally maintained zero surface cell pressure. Our purpose in this study was to investigate and characterize this feedback control system. We measured intracellular hydrostatic pressures in mouse lenses using a microelectrode/manometer-based system. We found that all feedback went through transport by the Na/K ATPase, which adjusted surface cell osmolarity such that pressure was maintained at zero. We traced the regulation of Na/K ATPase activity back to either TRPV4, which sensed positive pressure and stimulated activity, or TRPV1, which sensed negative pressure and inhibited activity. The inhibitory effect of TRPV1 on Na/K pumps was shown to signal through activation of the PI3K/AKT axis. The stimulatory effect of TRPV4 was shown in previous studies to go through a different signal transduction path. Thus, there is a local two-legged feedback control system for pressure in lens surface cells. The surface pressure provides a pedestal on which the pressure gradient sits, so surface pressure determines the absolute value of pressure at each radial location. We speculate that the absolute value of intracellular pressure may set the radial gradient in the refractive index, which is essential for visual acuity.
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Affiliation(s)
- Junyuan Gao
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Xiurong Sun
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Nicholas A Delamere
- Department of Physiology and Biophysics, University of Arizona, Tucson, Arizona
| | - Richard T Mathias
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York.
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Shi Q, Gu S, Yu XS, White TW, Banks EA, Jiang JX. Connexin Controls Cell-Cycle Exit and Cell Differentiation by Directly Promoting Cytosolic Localization and Degradation of E3 Ligase Skp2. Dev Cell 2015; 35:483-96. [PMID: 26585299 DOI: 10.1016/j.devcel.2015.10.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 09/10/2015] [Accepted: 10/18/2015] [Indexed: 10/22/2022]
Abstract
Connexins and connexin channels play important roles in cell growth/differentiation and tumorigenesis. Here, we identified a relationship between a connexin molecule and a critical cell-cycle regulator. Our data show that connexin (Cx) 50 regulated lens cell-cycle progression and differentiation by modulating expression of cyclin-dependent kinase inhibitor p27/p57 and E3 ubiquitin ligase Skp2. Cx50 directly interacted with and retained Skp2 in the cytosol by masking the nuclear targeting domain of Skp2, and this effect was supported by an increased nuclear localization of Skp2, disruption of Skp2 interaction with importin-7, and decreased levels of p27/p57 in mouse lenses lacking Cx50. As a result, Cx50 increased auto-ubiquitination and subsequent degradation of Skp2. A mutation (V362E) on the C terminus of Cx50 disrupted the interaction between Cx50 and Skp2 and completely abolished such effects. Therefore, this study identifies a role for connexins in regulating cell-cycle modulators and, consequently, cell growth and differentiation.
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Affiliation(s)
- Qian Shi
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Sumin Gu
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - X Sean Yu
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Thomas W White
- Department of Physiology and Biophysics, State University of New York, Stony Brook, NY 11794-8661, USA
| | - Eric A Banks
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Jean X Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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Santa Cruz A, Meşe G, Valiuniene L, Brink PR, White TW, Valiunas V. Altered conductance and permeability of Cx40 mutations associated with atrial fibrillation. J Gen Physiol 2015; 146:387-98. [PMID: 26503720 PMCID: PMC4621748 DOI: 10.1085/jgp.201511475] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [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: 07/14/2015] [Accepted: 09/23/2015] [Indexed: 11/20/2022] Open
Abstract
Gap junctions ensure the rapid propagation of the action potential throughout the myocardium. Three mutant forms of connexin40 (Cx40; A96S, M163V, and G38D), the primary component of the atrial gap junction channel, are associated with atrial fibrillation and retain the ability to form functional channels. We determined the biophysical properties of these mutant gap junctions in transiently transfected HeLa and N2A cells. All three mutants showed macroscopic junctional conductances over the range of 0.5 to 40 nS, and voltage dependences comparable to those of wild-type (WT) Cx40. However, the unitary conductance of G38D channels was ∼1.6-fold higher than that of WT Cx40 channels (∼220 vs. ∼135 pS), whereas the unitary conductances of the A96S and M163V mutants were similar to that of WT Cx40. Furthermore, the M163V and G38D channels exhibited approximately two- and approximately fivefold higher permeability to the anionic dye Lucifer yellow (LY) relative to K+ (LY/K+) compared with that of WT Cx40, whereas A96S LY transfer was similar to that of WT (G38D > M163V > A96S ≈ Cx40WT). In contrast, G38D channels were almost impermeable to cationic ethidium bromide (EtBr), suggesting that G38D alters channel selectivity. Conversely, A96S and M163V channels showed enhanced EtBr permeability relative to WT Cx40, with the following permeability order: M163V > A96S > Cx40WT > G38D. Altered conductive and permeability properties of mutant channels suggest an essential role for Cx40-mediated biochemical and electrical coupling in cardiac tissues. The altered properties of the three single-base substitution mutants may play a role in mechanisms of reentry arrhythmias.
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Affiliation(s)
- Ana Santa Cruz
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
| | - Gülistan Meşe
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
| | - Laima Valiuniene
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
| | - Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
| | - Virginijus Valiunas
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11792
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Majercik S, Vijayakumar S, Olsen G, Wilson E, Gardner S, Granger SR, Van Boerum DH, White TW. Surgical stabilization of severe rib fractures decreases incidence of retained hemothorax and empyema. Am J Surg 2015; 210:1112-6; discussion 1116-7. [PMID: 26454653 DOI: 10.1016/j.amjsurg.2015.08.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [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: 04/01/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 01/02/2023]
Abstract
BACKGROUND Retained hemothorax (RH) is relatively common after chest trauma and can lead to empyema. We hypothesized that patients who have surgical fixation of rib fractures (SSRF) have less RH and empyema than those who have medical management of rib fractures (MMRF). METHODS Admitted rib fracture patients from January 2009 to June 2013 were identified. A 2:1 propensity score model identified MMRF patients who were similar to SSRF. RH, and empyema and readmissions, were recorded. Variables were compared using Fisher exact test and Wilcoxon rank-sum tests. RESULTS One hundred thirty-seven SSRF and 274 MMRF were analyzed; 31 (7.5%) had RH requiring 35 interventions; 3 (2.2%) SSRF patients had RH compared with 28 (10.2%) MMRF (P = .003). Four (14.3%) MMRF subjects with RH developed empyema versus zero in the SSRF group (P = .008); 6 (19.3%) RH patients required readmission versus 14 (3.7%) in the non-RH group (P = .002). CONCLUSIONS Patients with rib fractures who have SSRF have less RH compared with similar MMRF patients. Although not a singular reason to perform SSRF, this clinical benefit should not be overlooked.
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Affiliation(s)
- Sarah Majercik
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT, 84107, USA.
| | - Sathya Vijayakumar
- Surgical Services Clinical Program, Intermountain Medical Center, Murray, UT, USA
| | - Griffin Olsen
- Surgical Services Clinical Program, Intermountain Medical Center, Murray, UT, USA
| | - Emily Wilson
- Division of Pulmonary and Critical Care Medicine, Intermountain Medical Center, Murray, UT, USA
| | - Scott Gardner
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT, 84107, USA
| | - Steven R Granger
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT, 84107, USA
| | - Don H Van Boerum
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT, 84107, USA
| | - Thomas W White
- Division of Trauma Services and Surgical Critical Care, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT, 84107, USA
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Abstract
Connexin mutations underlie numerous human genetic diseases. Several connexin genes have been linked to skin diseases, and mechanistic studies have indicated that a gain of abnormal channel function may be responsible for pathology. The topical accessibility of the epidermal connexins, the existence of several mouse models of human skin disease, and the ongoing identification of pharmacological inhibitors targeting connexins provide an opportunity to test new therapeutic approaches.
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Affiliation(s)
- Noah A Levit
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, United States
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, United States.
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Martinez JM, Wang HZ, Lin RZ, Brink PR, White TW. Differential regulation of Connexin50 and Connexin46 by PI3K signaling. FEBS Lett 2015; 589:1340-5. [PMID: 25935417 PMCID: PMC4433579 DOI: 10.1016/j.febslet.2015.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/16/2015] [Indexed: 01/28/2023]
Abstract
Gap junction channels can modify their activity in response to cell signaling pathways. Here, we demonstrate that Connexin50 (Cx50) coupling, but not Connexin46 (Cx46), increased when co-expressed with a constitutively active p110α subunit of PI3K in Xenopus oocytes. In addition, inhibition of PI3K signaling by blocking p110α, or Akt, significantly decreased gap junctional conductance in Cx50 transfected HeLa cells, with no effect on Cx46. Alterations in coupling levels were not a result of reduced Cx50 unitary conductance, suggesting that changes in the number of active channels were responsible. These data indicate that Cx50 is specifically regulated by the PI3K signaling pathway.
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Affiliation(s)
- Jennifer M Martinez
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Hong-Zhan Wang
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Thomas W White
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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Slavi N, Rubinos C, Li L, Sellitto C, White TW, Mathias R, Srinivas M. Connexin 46 (cx46) gap junctions provide a pathway for the delivery of glutathione to the lens nucleus. J Biol Chem 2014; 289:32694-702. [PMID: 25294879 PMCID: PMC4239621 DOI: 10.1074/jbc.m114.597898] [Citation(s) in RCA: 43] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 10/02/2014] [Indexed: 01/27/2023] Open
Abstract
Maintenance of adequate levels of glutathione (GSH) in the lens nucleus is critical for protection of lens proteins from the effects of oxidative stress and for lens transparency. How GSH is transported to the nucleus is unknown. We show that GSH diffuses to the nucleus from the outer cortex, where a high concentration of the anti-oxidant is established by synthesis or uptake, via the network of gap junctions. Using electrophysiological measurements, we found that channels formed by Cx46 and Cx50, the two connexin isoforms expressed in the lens, were moderately cation-selective (P(Na)/P(Cl) ∼5 for Cx46 and ∼3 for Cx50). Single channel permeation of the larger GSH anion was low but detectable (P(Na)/P(GSH) ∼12 for Cx46 and ∼8 for Cx50), whereas permeation of divalent anion glutathione disulfide (GSSG) was undetectable. Measurement of GSH levels in the lenses from connexin knock-out (KO) mice indicated Cx46, and not Cx50, is necessary for transport of GSH to the core. Levels of GSH in the nucleus were markedly reduced in Cx46 KO, whereas they were unaffected by Cx50 KO. We also show that GSH delivery to the nucleus is not dependent on the lens microcirculation, which is believed to be responsible for extracellular transport of other nutrients to membrane transporters in the core. These results indicate that glutathione diffuses from cortical fiber cells to the nucleus via gap junction channels formed by Cx46. We present a model of GSH diffusion from outer cells to inner fiber cells through gap junctions.
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Affiliation(s)
- Nefeli Slavi
- From the Department of Biological and Vision Sciences and the Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York 10036 and
| | - Clio Rubinos
- From the Department of Biological and Vision Sciences and the Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York 10036 and
| | - Leping Li
- the Department of Physiology and Biophysics, State University of New York, Stony Brook, New York 11794
| | - Caterina Sellitto
- the Department of Physiology and Biophysics, State University of New York, Stony Brook, New York 11794
| | - Thomas W White
- the Department of Physiology and Biophysics, State University of New York, Stony Brook, New York 11794
| | - Richard Mathias
- the Department of Physiology and Biophysics, State University of New York, Stony Brook, New York 11794
| | - Miduturu Srinivas
- From the Department of Biological and Vision Sciences and the Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York 10036 and
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Levit NA, Sellitto C, Wang HZ, Li L, Srinivas M, Brink PR, White TW. Aberrant connexin26 hemichannels underlying keratitis-ichthyosis-deafness syndrome are potently inhibited by mefloquine. J Invest Dermatol 2014; 135:1033-1042. [PMID: 25229253 PMCID: PMC4363291 DOI: 10.1038/jid.2014.408] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [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: 05/29/2014] [Revised: 08/02/2014] [Accepted: 09/04/2014] [Indexed: 11/27/2022]
Abstract
Keratitis-ichthyosis-deafness (KID) syndrome is an ectodermal dysplasia caused by dominant mutations of connexin26 (Cx26). Loss of Cx26 function causes non-syndromic sensorineural deafness, without consequence in the epidermis. Functional analyses have revealed that a majority of KID-causing mutations confer a novel expansion of hemichannel activity, mediated by connexin channels in a non-junctional configuration. Inappropriate Cx26 hemichannel opening is hypothesized to compromise keratinocyte integrity and epidermal homeostasis. Pharmacological modulators of Cx26 are needed to assess the pathomechanistic involvement of hemichannels in the development of hyperkeratosis in KID syndrome. We have used electrophysiological assays to evaluate small molecule analogs of quinine for suppressive effects on aberrant hemichannel currents elicited by KID mutations. Here, we show that mefloquine inhibits several mutant hemichannel forms implicated in KID syndrome when expressed in Xenopus laevis oocytes (IC50≈16µM), using an extracellular divalent cation, zinc (Zn++), as a non-specific positive control for comparison (IC50≈3µM). Furthermore, we used freshly isolated transgenic keratinocytes to show that micromolar concentrations of mefloquine attenuated increased macroscopic membrane currents in primary mouse keratinocytes expressing human Cx26-G45E, a mutation causing a lethal form of KID syndrome.
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Affiliation(s)
- Noah A Levit
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Caterina Sellitto
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Hong-Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Leping Li
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Miduturu Srinivas
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, USA
| | - Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA.
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Skedros JG, Mears CS, Langston TD, Van Boerum DH, White TW. Medial scapular winging associated with rib fractures and plating corrected with pectoralis major transfer. Int J Surg Case Rep 2014; 5:750-3. [PMID: 25238337 PMCID: PMC4189053 DOI: 10.1016/j.ijscr.2014.08.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/12/2014] [Accepted: 08/24/2014] [Indexed: 11/18/2022] Open
Abstract
Long thoracic nerve injury is a potential complication of rib fracture fixation. Long thoracic nerve injury from rib fracture fixation has not been reported. Long thoracic nerve injury can be corrected surgically by pectoralis major transfer.
INTRODUCTION Rib plating is becoming increasingly common as a method for stabilizing a flail chest resulting from multiple rib fractures. Recent guidelines recommend surgical stabilization of a flail chest based on consistent evidence of its efficacy and lack of major safety concerns. But complications of this procedure can occur and are wide ranging. PRESENTATION OF CASE We report an interesting case of a 58-year-old male patient that worked as a long-distance truck driver and had a flail chest from multiple bilateral rib fractures that occurred when his vehicle was blown over in a wind storm. He underwent open reduction with internal fixation (ORIF) of the bilateral rib fractures and they successfully healed. However, he had permanent long thoracic nerve injury on the side with the most severe trauma. This resulted in symptomatic scapular winging that impeded him from long-distance truck driving. The scapular winging was surgically corrected nearly two years later with a pectoralis major transfer augmented with fascia lata graft. The patient had an excellent final result. DISCUSSION We report this case to alert surgeons who perform rib fracture ORIF that long thoracic nerve injury is a potential iatrogenic complication of that procedure or might be a result of the chest wall trauma. CONCLUSION Although the specific cause of the long thoracic nerve injury could not be determined in our patient, it was associated with chest wall trauma in the setting of rib fracture ORIF. The scapular winging was surgically corrected with a pectoralis major transfer.
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Affiliation(s)
- John G Skedros
- The University of Utah, Department of Orthopaedic Surgery, Salt Lake City, UT, USA; Utah Orthopaedic Specialists, Salt Lake City, UT, USA; Intermountain Medical Center, Salt Lake City, UT, USA.
| | - Chad S Mears
- Utah Orthopaedic Specialists, Salt Lake City, UT, USA.
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Majercik S, Cannon Q, Granger SR, VanBoerum DH, White TW. Long-term patient outcomes after surgical stabilization of rib fractures. Am J Surg 2014; 208:88-92. [PMID: 24507379 DOI: 10.1016/j.amjsurg.2013.08.051] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 08/13/2013] [Accepted: 08/16/2013] [Indexed: 12/21/2022]
Abstract
BACKGROUND Rib fractures are common, and can be disabling. Recently, there has been increased interest in surgical stabilization of rib fractures (SSRF). It is difficult to define long-term benefits of the procedure. This is a descriptive study of patient outcomes after SSRF. METHODS SSRF patients between April 2010 and August 2012 at a Level I trauma center were identified. Data were collected from the medical records. A telephone survey asking about pain, satisfaction, and employment was administered to patients after hospital discharge. RESULTS One hundred-one patients met inclusion criteria. Fifty (50%) patients completed the survey. Indications for SSRF included flail chest, displaced fractures, pain, and inability to wean from mechanical ventilation. Pain was gone at 5.4 ± 1.1 weeks post discharge. Satisfaction with SSRF on a scale of 1 to 10 was 9.2 ± .2. Ninety percent of employed patients returned to the same work at 8.5 ± 1.2 weeks. CONCLUSIONS SSRF patients are satisfied and are able to return to normal activity with few limitations. A prospective study using modern rib fixation technology is needed to further define benefits.
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Affiliation(s)
- Sarah Majercik
- Division of Trauma Services and Critical Care Medicine, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT 84157, USA.
| | - Quinn Cannon
- Division of Trauma Services and Critical Care Medicine, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT 84157, USA
| | - Steven R Granger
- Division of Trauma Services and Critical Care Medicine, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT 84157, USA
| | - Don H VanBoerum
- Division of Trauma Services and Critical Care Medicine, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT 84157, USA
| | - Thomas W White
- Division of Trauma Services and Critical Care Medicine, Intermountain Medical Center, 5121 South Cottonwood Street, Murray, UT 84157, USA
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Valiunas V, Cruz AS, Valiuniene L, Mese G, White TW, Brink PR. Biophysical Properties of CX40 Mutants Linked to Atrial Fibrillation. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.3110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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49
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Sellitto C, Li L, Gao J, Robinson ML, Lin RZ, Mathias RT, White TW. AKT activation promotes PTEN hamartoma tumor syndrome-associated cataract development. J Clin Invest 2013; 123:5401-9. [PMID: 24270425 DOI: 10.1172/jci70437] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 09/12/2013] [Indexed: 01/03/2023] Open
Abstract
Mutations in the human phosphatase and tensin homolog (PTEN) gene cause PTEN hamartoma tumor syndrome (PHTS), which includes cataract development among its diverse clinical pathologies. Currently, it is not known whether cataract formation in PHTS patients is secondary to other systemic problems, or the result of the loss of a critical function of PTEN within the lens. We generated a mouse line with a lens-specific deletion of Pten (PTEN KO) and identified a regulatory function for PTEN in lens ion transport. Specific loss of PTEN in the lens resulted in cataract. PTEN KO lenses exhibited a progressive age-related increase in intracellular hydrostatic pressure, along with, increased intracellular sodium concentrations, and reduced Na+/K+-ATPase activity. Collectively, these defects lead to lens swelling, opacities and ultimately organ rupture. Activation of AKT was highly elevated in PTEN KO lenses compared to WT mice. Additionally, pharmacological inhibition of AKT restored normal Na+/K+-ATPase activity in primary cultured lens cells and reduced lens pressure in intact lenses from PTEN KO animals. These findings identify a direct role for PTEN in the regulation of lens ion transport through an AKT-dependent modulation of Na+/K+-ATPase activity, and provide a new animal model to investigate cataract development in PHTS patients.
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50
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Abstract
PURPOSE Age-related nuclear cataracts involve denaturation and aggregation of intracellular proteins. We have documented age-dependent changes in membrane transport in the mouse lens to see what might initiate changes in the intracellular milieu. METHODS Microelectrode-based intracellular impedance studies of intact lenses were used to determine gap junction coupling conductance, fiber and surface cell membrane conductances, effective extracellular resistivity, and intracellular voltage. Fiber cell connexin expression was detected by Western blotting. Intracellular hydrostatic pressure was measured with a microelectrode/manometer system. Concentrations of intracellular sodium and calcium were measured by intracellular injection of sodium-binding benzofuran isophthalate and Fura2, respectively. RESULTS In adult lenses, as age increased: fiber cell gap junction coupling conductance declined significantly, correlating with decreases in Cx46 and Cx50 labeling in Western blots; fiber and surface cell membrane conductances did not change systematically; effective extracellular resistivity increased monotonically; center to surface gradients for intracellular pressure, sodium, calcium, and voltage all increased, but in an interdependent manner that moderated changes. In newborn pup lenses, there were changes that did not simply fit with the above paradigm. CONCLUSIONS In newborn pup lenses, the observed changes may relate to growth factors that are not related to age-dependent changes seen in adult lenses. The major change in adult lenses was an age-dependent decrease in gap junction coupling, probably due to oxidative damage leading to degradation of connexin proteins. These changes clearly lead to compromise of intracellular homeostasis and may be a causal factor in age-related nuclear cataracts.
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Affiliation(s)
- Junyuan Gao
- Department of Physiology & Biophysics, SUNY at Stony Brook, Stony Brook, New York
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