title: Immunohistochemical Evaluation of Idiopathic Epiretinal Membranes and In Vitro Studies on the Effect of TGF-β on Müller Cells.
abstract: OBJECTIVE
  The purpose of this study was to investigate the presence of type VI collagen and glial cells in idiopathic epiretinal membrane (iERM) and the role of TGF-β in the expression of collagens and α-smooth muscle actin (α-SMA) in retinal Müller cells.
  
  
  METHODS
  Idiopathic ERM samples from vitrectomy were analyzed for glial acidic fibrillary protein (GFAP), cellular retinaldehyde-binding protein (CRALBP), α-SMA, and type VI collagen using flat-mount immunohistochemistry. To study intracellular collagen expression in relation to cellular phenotype, spontaneously immortalized human Müller cells (MIO-M1) were treated with TGF-β1 for 48 hours, and the expression of α-SMA and intracellular type I, II, IV, and VI collagens was studied by using immunocytology. Findings in Müller cells were compared with those in fetal lung fibroblasts and newborn skin fibroblasts.
  
  
  RESULTS
  A colocalization of GFAP/CRALBP and GFAP/α-SMA was found in iERM, indicating a dynamic process of activation of retinal Müller cells in vivo. Transforming growth factor-β1 induced up-regulation of α-SMA stress fibers in retinal Müller cells and both types of fibroblasts in vitro. The intracellular staining intensity of type I, II, and VI collagens was decreased in retinal Müller cells containing α-SMA stress fibers, whereas the intracellular staining intensity of type I and VI collagens in both types of fibroblasts was not affected.
  
  
  CONCLUSIONS
  Type VI collagen and activated retinal Müller cells are present in iERM. Transforming growth factor-β1 induces an up-regulation of α-SMA stress fibers in retinal Müller cells and fibroblasts and appears to have a cell-specific effect on intracellular collagen expression.
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands 2W.J. Kolff Institute, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands 3Tianjin Medica.
authors.forename: Shao-Chong
authors.initials: SC
authors.lastname: Bu
authors.affiliation: W.J. Kolff Institute, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands 4Department of Biomedical Engineering (FB40), University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Kuijer
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands 2W.J. Kolff Institute, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands.
authors.forename: Roelofje J
authors.initials: RJ
authors.lastname: van der Worp
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands.
authors.forename: Gina
authors.initials: G
authors.lastname: Postma
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands.
authors.forename: Victor W
authors.initials: VW
authors.lastname: Renardel de Lavalette
authors.affiliation: Tianjin Medical University Eye Centre, Nan Kai District, Tianjin, China.
authors.forename: Xiao-Rong
authors.initials: XR
authors.lastname: Li
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands 2W.J. Kolff Institute, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands.
authors.forename: Johanna M M
authors.initials: JM
authors.lastname: Hooymans
authors.affiliation: Department of Ophthalmology (BB61), University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands 2W.J. Kolff Institute, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands.
authors.forename: Leonoor I
authors.initials: LI
authors.lastname: Los
mesh_terms: D000199:Actins / Q000096:biosynthesis / Q000235:genetics*; D000368:Aged; D000369:Aged, 80 and over; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D002478:Cells, Cultured; D024142:Collagen Type VI / Q000096:biosynthesis / Q000235:genetics*; D063928:Ependymoglial Cells / Q000187:drug effects / Q000378:metabolism*; D019773:Epiretinal Membrane / Q000235:genetics* / Q000378:metabolism / Q000628:therapy; D005260:Female; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011347:Procollagen; D012313:RNA / Q000235:genetics; D012172:Retinaldehyde; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D014821:Vitrectomy
chemical_list: C020932:11-cis-retinal-binding protein; C541116:ACTA2 protein, human; D000199:Actins; D002352:Carrier Proteins; D024142:Collagen Type VI; D005904:Glial Fibrillary Acidic Protein; D011347:Procollagen; D053773:Transforming Growth Factor beta1; D012313:RNA; D012172:Retinaldehyde