Type VII Collagen in the Human Accommodation System: Expression in Ciliary Body, Zonules, and Lens Capsule.

Purpose: To investigate intraocular expression of COL7A1 and its protein product type VII collagen, particularly at the accommodation system.

Methods: Eyes from 26 human adult donors were used. COL7A1 expression was analyzed in ex vivo ciliary epithelium by microarray.

Type VII Collagen Expression in the Human Vitreoretinal Interface, Corpora Amylacea and Inner Retinal Layers.

Type VII collagen, as a major component of anchoring fibrils found at basement membrane zones, is crucial in anchoring epithelial tissue layers to their underlying stroma. Recently, type VII collagen was discovered in the inner human retina by means of immunohistochemistry, while proteomic investigations demonstrated type VII collagen at the vitreoretinal interface of chicken. Because of its potential anchoring function at the vitreoretinal interface, we further assessed the presence of type VII collagen at this site.

Immunohistochemical Evaluation of Idiopathic Epiretinal Membranes and In Vitro Studies on the Effect of TGF-β on Müller Cells.

Purpose: 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.

Substrate Elastic Modulus Regulates the Morphology, Focal Adhesions, and α-Smooth Muscle Actin Expression of Retinal Müller Cells.

Purpose: The stiffness of the extracellular matrix has been shown to regulate cell adhesion, migration, and transdifferentiation in fibrotic processes. Retinal Müller cells have been shown to be mechanosensitive; they are involved in fibrotic vitreoretinal diseases. Since fibrosis increases the rigidity of the extracellular matrix, our aim was to develop an in vitro model for studying Müller cell morphology and differentiation state in relation to matrix stiffness.

The Ultrastructural Localization of Type II, IV, and VI Collagens at the Vitreoretinal Interface.

Background: The vitreoretinal interface is the border of the cortical vitreous and the inner surface of the retina. The adhesion of the cortical vitreous to the ILM, namely vitreoretinal adhesion, involves a series of complex molecular adhesion mechanisms and has been considered as an important pathogenic factor in many vitreoretinal diseases. The presence of type VI collagen at the vitreoretinal interface and its possible interaction with collagens and glycoproteins indicates that type VI collagen may contribute to the vitreoretinal adhesion.

Glial cells and collagens in epiretinal membranes associated with idiopathic macular holes.

Purpose: To investigate the identity of collagens and cellular components in the epiretinal membrane (ERM) associated with full-thickness idiopathic macular hole and their clinical relevance.

Methods: Pars plana vitrectomy with the peeling of internal limiting membrane and ERM was performed by 2 surgeons in 40 eyes with idiopathic macular holes. The clinical data were reviewed and the surgical specimens were processed for flat-mount and immunohistochemical analysis.

Intraocular degradation behavior of crosslinked and linear poly(trimethylene carbonate) and poly(D,L-lactic acid).

The intraocular degradation behavior of poly(trimethylene carbonate) (PTMC) networks and poly(D,L-lactic acid) (PDLLA) networks and of linear high molecular weight PTMC and PDLLA was evaluated. PTMC is known to degrade by enzymatic surface erosion in vivo, whereas PDLLA degrades by hydrolytic bulk degradation. Rod shaped specimens were implanted in the vitreous of New Zealand white rabbits for 6 or 13 wk.

Enzymatic breakdown of type II collagen in the human vitreous.

Purpose: To investigate whether enzymatic collagen breakdown is an active process in the human vitreous.

Methods: Human donor eyes were used for immunohistochemistry to detect the possible presence of the matrix metalloproteinase (MMP)-induced type II collagen breakdown product col2-3/4C-short in the vitreous. Western blot and slot blot analyses were used to further identify vitreal type II collagen breakdown products in three age groups with average ages of 25, 45, and 65 years.

Mature enzymatic collagen cross-links, hydroxylysylpyridinoline and lysylpyridinoline, in the aging human vitreous.

Purpose: The vitreous body of the human eye undergoes progressive morphologic changes with aging. Since the enzymatic collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are known to be important for the integrity of the collagen matrix, the presence in the vitreous on aging was studied.

Methods: Vitreous bodies (VBs; n = 143) from 119 donors (age 4-80 years; mean +/- SD, 54.

Collagen distribution in the human vitreoretinal interface.

Purpose: To evaluate the presence of collagen types I to VII, IX, XI, and XVIII at the posterior pole, the equator and the pre-equatorial area in human donor eyes, since collagens are important macromolecules that contribute to vitreoretinal adhesion at the vitreoretinal interface.

Methods: Freshly isolated human retinectomy samples from the equator were used for reverse transcription-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 collagens and evaluated by light microscopy (LM).

Human retinal Müller cells synthesize collagens of the vitreous and vitreoretinal interface in vitro.

Purpose: To investigate the capacity of cultured Müller cells to synthesize collagens, since previous studies indicated that Müller cells could be involved in collagen remodeling at the vitreoretinal border in adult human eyes.

Methods: Spontaneously immortalized cultured human Müller cells were analyzed for the presence of mRNA of types I-VII, IX, XI, and XVII collagen by RT-PCR. Furthermore, Müller cells were immunocytochemically stained for light microscopic (LM) evaluation of these collagens and their main characteristics.

In vitro phagocytosis of collagens by immortalised human retinal Müller cells.

Purpose: This study is a first step to investigate phagocytosis of collagens by human retinal Müller cells, since Müller cells could be involved in remodelling of the vitreous and vitreoretinal interface in the human eye.

Methods: Müller cells in culture were exposed to 2.0 microm fluorescent latex beads coated with BSA and human types I, II, and IV collagen and to non-coated beads for 2, 12, 24, and 48 h.

Packages of vitreous collagen (type II) in the human retina: an indication of postnatal collagen turnover?

The purpose of this study was to evaluate the vitreoretinal border in the (pre-)equatorial area in nonpathologic human donor eyes, because the majority of retinal defects induced by posterior vitreous detachment (PVD) are located there. Nine eyes (24-80 years) were fixed and embedded in Technovit 8100. After evaluation by light microscope, areas of interest were selected for immunotransmission electron microscope.

Presence of collagen IV in the ciliary zonules of the human eye: an immunohistochemical study by LM and TEM.

The ciliary zonules of the eye are composed of fibrillar and non-fibrillar components. Fibrils provide tensile strength and elasticity, whereas non-fibrillar components serve as a coating surrounding the fibrils. This coating behaves as a barrier to macromolecules.

Age-related liquefaction of the human vitreous body: LM and TEM evaluation of the role of proteoglycans and collagen.

Purpose: To evaluate morphologic aspects of age-related liquefaction of the human vitreous body by light and electron microscopy to provide a basis from which future studies directed at the pathogenesis of this phenomenon can be undertaken. The study focuses on changes in fibrillar collagen and proteoglycans (PGs).

Methods: Morphologic aspects of intravitreal liquefied spaces and matrix areas surrounding them were examined in 13 adult human donor eyes (aged 21-80 years) by light (LM) and transmission electron microscopy (TEM).