Collagen distribution in the human vitreoretinal interface

¹ Ophthalmology, University Medical Center Groningen, P.O.box 30.001, Groningen, 9700 RB, Netherlands
² Pathology and Laboratory Medicine, Section Medical Biology, University of Groningen, Groningen, Netherlands; Pathology and Laboratory Medicine, Section Medical Biology, University Medical Center groningen, Groningen, Netherlands
³ Ophthalmology, University Medical Center Groningen, Groningen, Netherlands; Pathology and Laboratory Medicine, Section Medical Biology, University of Groningen, Groningen, Netherlands
⁴ Vitreoretinal Dept., The Rotterdam Eye Hospital, Schiedamsevest 180, Netherlands; Ophthalmology, Erasmus Medical Center Rotterdam, Rotterdam, United States
⁵ Ophthalmology, University Medical Center Groningen, P.O.box 30.001, Groningen, 9700 RB, Netherlands; Ophthalmology, University of Groningen, Groningen, Netherlands

^* To whom correspondence should be addressed. E-mail: t.l.ponsioen{at}ohk.umcg.nl.

	Abstract

Purpose. This study evaluates the presence of types I-VII, IX, XI, and XVIII collagen at the posterior pole, the equator and the pre-equatorial area in human donor eyes, since collagens are important macromolecules contributing to vitreoretinal adhesion at the vitreoretinal interface. Methods. Freshly isolated human retinectomy samples from the equator were used for reverse transcriptase-polymerase chain reaction to detect mRNA of the above-mentioned collagens. In addition, human donor eyes and equatorial retinectomy samples were embedded in paraffin, stained with antibodies against the above-mentioned collagens and evaluated by light microscopy (LM). Results. Retinectomy samples express mRNA of all tested collagen types. By LM, vitreous cortex is positive for types II, V, IX, and XI collagen. In all three regions within the donor eyes and in the retinectomy samples, the internal limiting lamina (ILL) shows types IV, VI, and XVIII collagen, the retinal vasculature is positive for types I-VI and XVIII collagen in most specimens, and retinal layers show condensed spots of type VII collagen. In addition, type VII collagen increases in density and in distribution over the retinal layers towards the posterior pole. Conclusions. Staining patterns of types I-V, IX, XI, and XVIII collagens are conform previous observations. Important new findings include the presence of type VI in the ILM and type VII in several layers of the retina. Both collagens can anchor matrix components and could be involved in vitreoretinal attachment. Furthermore, the presence of collagen mRNA in human retinectomy samples might be an indication of postnatal collagen production by retinal cells.

Key Words: extracellular matrix, vitreous humor, collagen, light microscopy, retina, human