Different collagen types define two types of idiopathic epiretinal membranes

Michaela Kritzenberger (1) , Benjamin Junglas (1) , Carsten Framme (2) , Horst Helbig (3) , Veit-Peter Gabel (3) , Rudolf Fuchshofer (1) , Ernst R Tamm (4) , Jost Hillenkamp (5)

1 Institute of Human Anatomy and Embryology
2 Inselspital Bern
3 Department of Ophthalmology
4 Institute of Human Anatomy and Embryology
5 CAU - Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel

Aims: To identify differences in extracellular matrix contents between idiopathic epiretinal membranes (IEM) of cellophane macular reflex (CMRM) or preretinal macular fibrosis (PMFM) type. Methods and results: IEM were analyzed by light and quantitative transmission electron microscopy, immunohistochemistry, and Western blotting. Substantial differences between CMRM and PMFM were observed regarding the nature of extracellular fibrils. In CMRM, the fibrils were thin with diameters between 6-15 nm. Between the fibrils, aggregates of long-spacing collagen were observed. In PMFM, the diameters of fibrils measured either 18-26 nm or 36-56 nm. By immunogold electron microscopy, 6-15 nm fibrils in CMRM were labeled for collagen type VI, while the fibrils in PMFM remained unstained. By Western blotting and immunohistochemistry, a strong signal for collagen type VI was observed in all CMRM, while immunoreactivity was weak or absent in PMFM. In contrast, PMFM showed immunoreactivity for collagen types I and II, which was weak or absent in CMRM. Both types of membranes showed immunoreactivity for collagen type III, IV, laminin and fibronectin with similar intensity. Conclusion: The presence of high amounts of collagen type VI in CMRM and the relative absence of collagen types I and II is the major structural difference to PMFM.

Mots clés: Medicine

Michaela Kritzenberger, Benjamin Junglas, Carsten Framme, Horst Helbig, Veit-Peter Gabel, et al.. Different collagen types define two types of idiopathic epiretinal membranes. Histopathology, 2011, 58 (6), pp.953. ⟨10.1111/j.1365-2559.2011.03820.x⟩. ⟨hal-00631272⟩