bromochloroacetic-acid and Diabetic-Retinopathy

We sought to characterize the angiofibrotic and apoptotic effects of vascular endothelial growth factor (VEGF)-inhibition on fibrovascular epiretinal membranes in eyes with traction retinal detachment because of proliferative diabetic retinopathy.. Membranes were excised from 20 eyes of 19 patients (10 randomized to intravitreal bevacizumab, 10 controls) at vitrectomy. Membranes were stained with antibodies targeting connective tissue growth factor (CTGF) or VEGF and colabeled with antibodies directed against endothelial cells (CD31), myofibroblasts, or retinal pigment epithelium markers. Quantitative and colocalization analyses of antibody labeling were obtained through immunofluorescence confocal microscopy. Masson trichrome staining, cell counting of hematoxylin and eosin sections, and terminal dUTP nick-end labeling staining were performed.. High levels of fibrosis were observed in both groups. Cell apoptosis was higher (P = 0.05) in bevacizumab-treated membranes compared with controls. The bevacizumab group had a nonsignificant reduction in colocalization in CD31-CTGF and cytokeratin-VEGF studies compared with controls. Vascular endothelial growth factor in extracted membranes was positively correlated with vitreous levels of VEGF; CTGF in extracted membranes was negatively correlated with vitreous levels of CTGF.. Bevacizumab suppresses vitreous VEGF levels, but does not significantly alter VEGF or CTGF in diabetic membranes that may be explained by high baseline levels of fibrosis. Bevacizumab may cause apoptosis within fibrovascular membranes.

Topics: Actins; Angiogenesis Inhibitors; Apoptosis; Bevacizumab; Cell Proliferation; Connective Tissue Growth Factor; Diabetic Retinopathy; Epiretinal Membrane; Fibrosis; Humans; Intravitreal Injections; Keratins; Platelet Endothelial Cell Adhesion Molecule-1; Prospective Studies; Receptors, Vascular Endothelial Growth Factor; Retina; Vascular Endothelial Growth Factor A; Vitrectomy

The Roundabout (Robo) family of proteins is related to the transmembrane receptors and plays a major role in neurogenesis. However, the role of the Robo proteins in proliferative retinopathy has not yet been defined. This study was conducted to determine whether Robo1 is expressed in the retina of patients with proliferative retinal disease and whether it has a pathobiological role in the disease.. Immunohistochemistry was used to determine the presence and distribution of Robo1 in the pathologic membranes in proliferative retinopathy. Small interfering (si)RNA technology was used to knockdown Robo1 expression and to study its effects on retinal pigment epithelial (RPE) cells in vitro. The impact on PVR development of blocking Robo1 expression was determined by applying specific siRNA in a PVR rabbit model. The prevalences of PVR and retinal detachment were determined by indirect ophthalmoscope on days 1, 3, 7, 14, 21, and 28 after the injection of RPE cells into the vitreous.. Immunohistochemistry showed that Robo1 expression was detected in GFAP-labeled glial cells and cytokeratin-labeled RPE cells in proliferative membranes. Robo1 expression was also detected in CD31-labeled vascular endothelial cells. Knockdown of Robo1 expression not only reduced human RPE cell proliferation in vitro but also effectively suppressed the development of PVR in a rabbit model.. Robo1 is present in the extracellular matrix of proliferative membranes and may be derived from dedifferentiated RPE cells. Silencing the expression of Robo1 in RPE cells inhibited cell proliferation and suppressed the development of PVR in an animal model, indicating a potential therapeutic usefulness in treating PVR.

Topics: Adolescent; Aged; Animals; Cell Line; Cell Movement; Cell Proliferation; Child; Diabetic Retinopathy; Disease Models, Animal; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Epiretinal Membrane; Female; Flow Cytometry; Fluorescent Antibody Technique, Indirect; Gene Silencing; Glial Fibrillary Acidic Protein; Humans; Keratins; Male; Middle Aged; Nerve Tissue Proteins; Neuroglia; Platelet Endothelial Cell Adhesion Molecule-1; Rabbits; Receptors, Immunologic; Retinal Pigment Epithelium; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Roundabout Proteins; Vitreoretinopathy, Proliferative; Young Adult

The purpose of this study was to first determine whether hypoxia-inducible factor-1α (HIF-1 α) was detectable in diabetic preretinal membranes and to compare the presence of HIF-1α in fibrovascular proliferative diabetic retinopathy membranes with nondiabetic, idiopathic, epiretinal membranes.. Twelve patients with proliferative diabetic retinopathy membranes requiring pars plana vitrectomy and nine nondiabetic patients with idiopathic epiretinal membranes requiring pars plana vitrectomy underwent excision of these membranes. Immunohisto-chemical staining for the presence of HIF-1α was performed on the excised membranes. The degree of staining for HIF-1α (1+, 2+, and 3+ scale) and the cellular location of staining were determined for each specimen. Institutional Review Board approval and informed consent were obtained for all patients.. Eleven of 12 (92%) diabetic preretinal membranes were positive for HIF-1α, and most had intense (2+ to 3+) cytoplasmic staining with occasional focal nuclear positivity. Five of 9 (55%) nondiabetic epiretinal membranes were positive for HIF-1α with significantly weaker cytoplasmic staining (1+ to 2+) with occasional focal punctuate nuclear staining.. Hypoxia-inducible factor-1α is found more often and more intensely in diabetic preretinal membranes compared with nondiabetic idiopathic epiretinal membranes.

Topics: Actins; Adult; Aged; Animals; Diabetic Retinopathy; Epiretinal Membrane; Female; Fluorescent Antibody Technique, Indirect; Glial Fibrillary Acidic Protein; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Keratins; Male; Membranes; Microscopy, Fluorescence; Middle Aged; Platelet Endothelial Cell Adhesion Molecule-1; Rabbits; Retinal Neovascularization; Staining and Labeling; Vascular Endothelial Growth Factor A; Vitrectomy

Atrial natriuretic peptide (ANP) has been recently described as an endogenous inhibitor of the synthesis and angiogenic action of vascular endothelial growth factor (VEGF). Given VEGF's key role in promoting neovascularization in proliferative diabetic retinopathy (PDR), this study was designed to evaluate the possibility that ANP could be involved in the neovascular and fibrotic complications of PDR.. We determined ANP by radioimmunoassay in plasma and vitreous humor samples collected from diabetic patients with and without PDR and from non-diabetic subjects. ANP was also immunohistochemically localized in the epiretinal membranes of patients with PDR.. Vitreous ANP concentrations were significantly higher in patients with active PDR compared to patients with quiescent PDR, diabetes without PDR or controls <0.05. Significant differences were also observed between vitreous ANP levels in diabetic patients without PDR and control subjects. There was no significant correlation between serum and vitreous ANP levels in any of the patient groups. ANP was detected in the fibrovascular epiretinal tissue of patients with PDR.. Diabetic patients with active neovascularization have significantly higher levels of ANP in the vitreous humor than those without active PDR. Diabetic patients without PDR were also found to have significantly higher vitreous ANP levels than non-diabetic patients. Since plasma and vitreous ANP concentrations were found to be unrelated, we suggest intraocular ANP synthesis and/or an increase in the release of ANP into the vitreous, as opposed to diffusion from the blood, as the main factors contributing to the high vitreous ANP levels observed in diabetic patients. In the fibrovascular epiretinal tissue of these patients, ANP was found to be localized in vascular, glial, fibroblast-like and retinal pigment epithelium cells. Our findings suggest a role for ANP in PDR.

Topics: Adult; Aged; Atrial Natriuretic Factor; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Epiretinal Membrane; Female; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Keratins; Male; Middle Aged; Radioimmunoassay; Retinal Neovascularization; Vitrectomy; Vitreous Body

Tangential traction in the macula from a thickened posterior hyaloid of the vitreous has been implicated as a cause of diffuse diabetic macular edema. Vitrectomy with peeling of the posterior hyaloid has been shown to reduce retinovascular leakage and improve vision in select patients. We report a clinicopathologic correlation using electron microscopy and electron immunocytochemistry to characterize the membrane infiltrating the posterior hyaloid in two such patients.. Two patients presented with vision loss associated with diffuse diabetic macular edema and an attached, thickened, and taut posterior hyaloid. The patients underwent vitrectomy with peeling of the posterior hyaloid. The premacular posterior hyaloid specimens then were analyzed by electron microscopy with immunocytochemical staining for cytokeratin and glial fibrillary acidic protein.. Both posterior hyaloid specimens contained collagen and a large cellular component. Immunogold labeling showed cells positive for glial fibrillary acidic protein or cytokeratin. With double labeling, no cells expressed both proteins simultaneously. Clinically, both patients had vision improvement and macular edema resolution after surgery.. The thickened, taut posterior hyaloid observed in our patients with diabetic macular edema contained cells of glial and epithelial origin. This cellular infiltration may contribute to abnormal vitreomacular adherence and could play a role in the pathogenesis of macular edema in some patients with diabetes.

Topics: Adult; Aged; Diabetic Retinopathy; Eye Diseases; Glial Fibrillary Acidic Protein; Humans; Keratins; Macular Edema; Male; Microscopy, Immunoelectron; Vitrectomy; Vitreous Body

To evaluate the characteristics of cellular proliferation in different retinal diseases.. Three specific antibodies [to cytokeratin (CK), glial fibrillary acidic protein (GFAP) and actin, respectively] were used. Vitrectomy specimens from 28 cases with different proliferative retinal diseases were studied immunohistochemically.. In the vitreous with proliferative vetreoretinopathy (PVR), most of the proliferative cells were derived from glial and retinal pigment epithelial (RPE) cells. In the vitreous of proliferative diabetic retinopathy (PDR), RPE cells might enhance the contraction of proliferative membranes. Increase in actin in firovascular membranes with PDR may play a positive role on the pericytes dropping out from microvessels.. The cell proliferation in the vitreous associated with the increase of levels of growth factors in pathological vitreous, possibly, is one of the mechanisms for the deterioration of proliferative retinal diseases.

Topics: Actins; Adult; Antibodies; Cell Division; Diabetic Retinopathy; Glial Fibrillary Acidic Protein; Humans; Immunohistochemistry; Keratins; Middle Aged; Pigment Epithelium of Eye; Retinal Vein Occlusion; Vitrectomy; Vitreoretinopathy, Proliferative; Vitreous Body

In the late stages of proliferative diabetic retinopathy (PDR) the vascularized posterior cortical gel (PCG) contracts leading to a partial posterior hyaloidal separation, hemorrhage, and traction retinal detachment (TRD). "Additional epiretinal membranes" have been described previously. These are thin, usually transparent epiretinal membranes which extend anteriorly from the point of attachment of the elevated posterior cortical gel to the edge of the TRD. The origin and frequency of the occurrence as well as the clinical significance of such additional epiretinal membranes are the subjects of controversy.. To quantitate the authors' clinical impression that additional epiretinal membranes are common in advanced PDR, to characterize them immunohistochemically, and to demonstrate the rationale for the authors' surgical approach.. Intraoperative observations for all patients undergoing diabetic vitrectomy and delamination over the last 2 years were reviewed retrospectively. The presence of additional epiretinal membrane was searched for in the initial stages of vitrectomy. When identified, their apparent continuity with the elevated portion of the PCG was confirmed. Surgical specimens were obtained from nine patients for immunohistochemical study.. Additional epiretinal membranes were observes in 145 (81%) of 179 consecutive eyes with PDR that underwent surgery for macular TRD. Immunohistochemical staining with type II collagen antibody was positive in all specimens, suggesting that these membranes were of vitreous origin.. It is likely that the additional epiretinal membranes represent the posterior leaf of a split PCG, the anterior leaf being the elevated portion of the PCG. The two leaves remain fused in the main, fibrovascular portion of the epiretinal membrane. These findings help explain the clinical experience that once the posterior leaf of the PCG is identified and elevated, it provides an accurate point of entry into the surgical plane facilitating delamination of the fused (vascularized) portion of the PCG from the detached retina.

Topics: Aged; Collagen; Diabetic Retinopathy; Eye Diseases; Female; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Keratins; Male; Middle Aged; Retinal Detachment; Retrospective Studies; Vitrectomy; Vitreoretinopathy, Proliferative; Vitreous Body

Immunohistochemical techniques were used to investigate the relation between retinal pigment epithelial cells (RPE), traction retinal detachment (TRD) membranes, and combined traction rhegmatogenous retinal detachment (CTR) membranes in proliferative diabetic retinopathy. Seven CTR and five TRD membranes were obtained during closed microsurgery. Six of the seven CTR membranes and one of the five TRD membranes contained RPE. Eleven of the 12 diabetic membranes incorporated glial cells. The findings emphasise that the intravitreal membranes of proliferative diabetic retinopathy contain a diversity of cell types and indicate that RPE tend to contribute to CTR, rather than TRD, membranes. The histopathological appearance of CTR membranes is that of a hybrid between TRD and proliferative vitreo-retinopathy membranes.

Topics: Diabetic Retinopathy; Humans; Immunohistochemistry; Keratins; Pigment Epithelium of Eye; Retinal Detachment