Intraoperative challenges and management of fibrovascular membrane with tractional retinoschisis in proliferative diabetic retinopathy.

BACKGROUND: In severe Proliferative Diabetic Retinopathy (PDR), fibrovascular membrane (FVM) causes macular tractional retinal detachment (MTRD) which threatens vision and eventually leads to blindness. Here we present a case of separation between the inner and outer retina in tractional retinoschisis, induced during intraoperative FVM delamination. CASE PRESENTATION: A 68-year-old woman presented with PDR in the right eye, characterized by a combined FVM and retinal detachment, for which a vitrectomy was performed. Multiple holes, large retinal detachment extending to all quadrants, and white-lined blood vessels with FVM were found during the procedure. When membrane delamination was performed, it strayed into the space between the inner and outer retinal layers without being noticed due to retinoschisis and multiple retinal holes. After removing the FVM and detaching the separated inner retina, fluid-gas and photocoagulation were performed. Retinal reattachment was successfully achieved after surgery, and the postoperative visual acuity was improved and maintained for 26 months postoperatively. CONCLUSIONS: When tractional retinoschisis due to FVM is combined with retinal holes in tractional retinal detachment (TRD), care must be taken to prevent delamination from straying into retinoschisis during separation.

Mingjing granule inhibits the subretinal fibrovascular membrane of two-stage laser-induced neovascular age-related macular degeneration in rats.

Objective: The study aims to investigate the protective effect of Mingjing granule (MG) in a fibrovascular membrane rat model of neovascular age-related macular degeneration (nAMD) and explore the underlying mechanism. Methods: The nAMD fibrovascular membrane model was established by two-stage laser photocoagulation. BN rats were randomly divided into four groups: the model group was gavaged with distilled water, the anti-VEGF group was given an intravitreous injection of ranibizumab, the MG + anti-VEGF group was gavaged with MG combined with an intravitreous injection of ranibizumab, and the normal group not modeled only fed conventionally. Lesions were evaluated by color fundus photograph, optical coherence tomography, fundus fluorescein angiography, and retinal pigment epithelial-choroid-sclera flat mount. The changes in the retinal structure were observed by histopathology. The expression of inflammatory cell markers F4/80, Iba-1, and glial fibrillary acidic protein (GFAP); the fibrosis-related factors collagen-1, fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor-beta (TGF-ß); and the complement system-related factors C3a and C3aR in the retina were detected by immunofluorescence or qRT-PCR. Results: The current study revealed that MG + anti-VEGF administration more significantly reduced the thickness of fibrovascular lesions, suppressed vascular leakage (exudation area and mean density value), inhibited the area of fibrovascular lesions, and restrained the formation of the fibrovascular membrane than the anti-VEGF agent alone in the two-stage laser-induced rat model. The fluorescence intensities of F4/80, Iba-1, collagen-1, fibronectin, TGF-ß, and C3aR showed more significant inhibition in MG + anti-VEGF-treated rats than the anti-VEGF agent alone. The mRNA expression levels of F4/80, Iba-1, GFAP, collagen-1, fibronectin, α-SMA, TGF-ß, and C3a showed lower levels in rats treated with MG + anti-VEGF than the anti-VEGF agent alone. Conclusion: Combining MG with anti-VEGF treatment inhibits the growth of the fibrovascular membrane more effectively than using anti-VEGF treatment alone. The mechanism underlying this effect may involve limiting inflammatory cell aggregation, controlling complement system activation, and decreasing the expression of the fibrotic protein.

miR-92a and integrin expression in fibrovascular membranes in proliferative diabetic retinopathy.

Diabetic retinopathy (DR) is a leading cause of vision impairment. The proliferative form of DR (PDR) involves fibrovascular membrane (FVM) formation at the vitreoretinal interface. MicroRNAs (miRNAs) are a class of non-coding RNA molecules that play an important role in gene regulation; a single miRNA could regulate multiple genes. We previously reported that miR-92a, a suppressor of integrins α5 and αv, was downregulated in DR. Considering the integrin's role in FVM pathology and the potential involvement of miR-92a in DR, we asked a question whether miR-92a could play a critical role in FVM pathology. We collected the FVM and epiretinal membranes of individuals with PDR and macular pucker (control) undergoing pars plana vitrectomy. The frozen sections of membranes were stained for α5 and αvß3 integrins. The miR-92a levels were assessed using real-time quantitative PCR. The FVMs of individuals with PDR stained brighter for integrin subunits α5 and αvß3 compared to the epiretinal membranes of subjects with macular pucker. miR-92a levels were decreased in FVM subjects. In conclusion, our studies demonstrate that miR-92a decrease is associated with an increase in integrins α5 and αvß3, thus contributing to the inflammatory milieu in PDR.

Study on the effects of different anti-VEGF drugs on fibrovascular membranes of proliferative diabetic retinopathy.

PURPOSE: To investigate the effects of different anti-VEGF drugs on fibrovascular membranes (FVM) in proliferative diabetic retinopathy (PDR). In addition, in vitro model was used to simulate the intraocular fibroblasts barrier to explore the penetration of different anti-VEGF drugs. METHODS: 24 eyes from 24 PDR patients with FVM were recruited for this prospective observational study. The patients were randomized to receive one of three anti-VEGF drugs (Ranibizumab, Conbercept, or Aflibercept). Then neovascular structures were assessed by optical coherence tomography angiography (OCTA) before intravitreal injection (pre-IVT) and 1, 2, and 3 days after intravitreal injection (post-IVT). The changes in vessels area (VSA), vessels percentage area (VPA), junction density (JD), and average lacunarity (AL) were analyzed by using the image processing software Angiotool. In vitro penetrating model with fibroblasts barrier was used to compare the effects of the three drugs on human retinal vascular endothelial cells (HRVECs) over 3 days by Cell proliferation measurement. Moreover, the drug concentrations in the penetrating model were detected by liquid chromatography-mass spectrometry (LC-MS). RESULTS: The VSA, VPA, and JD all decreased, while the AL increased in Ranibizumab group(n = 8), Conbercept group (n = 8), and Aflibercept group (n = 8) within 3 days (P<0.05). Meanwhile, under the condition of the same amount of substance, the inhibition effect of Ranibizumab on HRVEC was the strongest in the penetrating model evaluated by CCK8 absorbance experiments of HRVECs (FCCK8=6.493, PCCK8= 0.0051), and the number of transmembrane molecules in the Ranibizumab group was also the largest within 3 days (F = 8.209, P = 0.0006) among the three groups. CONCLUSION: Angiotool is feasible to reconstruct the neovascular structure on the FVM in OCTA images. The three different anti-VEGF drugs can significantly reduce the vascular area and density on the proliferating membranes, and there is no significant difference in the anti-neovascularization among the three drugs clinically. However, small molecule drug is more penetrating and move faster across membranes in vitro cell model. CLINICAL TRIAL REGISTRATION: This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn, registration number ChiCTR2300067476).

Effect of Mingjing Granules on Fibrovascular Membrane of Wet Age-related Macular Degeneration Based on Macrophages and Glial Cells / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Mingjing granules （MJKL） on the fibrovascular membrane of experimental wet age-related macular degeneration （nAMD） based on macrophages and glial cells and further explain the mechanism of MJKL in the treatment of nAMD. MethodThe experimental nAMD fibrovascular membrane model was established by two-stage laser photocoagulation. BN rats were randomly divided into three groups： model group， anti-vascular endothelial growth factor （VEGF） group， and MJKL + anti-VEGF group. The model group was given distilled water for intragastric administration. Anti-VEGF group was injected with leizumab injection in the vitreous cavity. MJKL + anti-VEGF group was injected with leizumab injection in the vitreous cavity， and MJKL was intragastrically administered. Ten normal BN rats were not modeled and fed as controls. After 40 days of model making， fundus lesion morphology， lesion exudation area， and MD value were observed by fundus photography （FP）， fundus angiography （FFA）， optical coherence tomography （OCT）， and retinal pigment epithelium （RPE）-choroid-sclera film. The changes in retinal structure were observed by histopathology， and the expression and distribution of F4/80， Iba-1， and GFAP were detected by immunofluorescence. The relative expression levels of F4/80， Iba-1， and GFAP mRNA were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultThe fibrovascular membrane model was established 40d after two-stage laser modeling. The lesion exudation area， MD value， lesion height， and lesion area in the anti-VEGF group were significantly lower than those in the model group （P<0.05）， and the retinal structural damage degree was significantly improved. Compared with the anti-VEGF group， the MJKL + anti-VEGF group significantly decreased the MD value， lesion height， and lesion area （P<0.05）， and lesion area and retinal structural damage degree were significantly improved. The fluorescence intensity of F4/80 and Iba-1 in the model group was significantly higher than that in the normal group （P<0.05）， and that in the anti-VEGF group was significantly lower than that in the model group （P<0.05）. The fluorescence intensity in the MJKL + anti-VEGF group was significantly lower than that in the anti-VEGF group （P<0.05）. The fluorescence intensity of GFAP in the model group was significantly higher than that in the normal group （P<0.05）， and that in the anti-VEGF group was significantly lower than that in the model group （P<0.05）. The relative expression levels of F4/80， Iba-1， and GFAP mRNA in the model group were significantly increased compared with the normal group （P<0.05）， and the anti-VEGF group was significantly decreased compared with the model group （P<0.05）. The relative expression levels of F4/80， Iba-1， and GFAP mRNA in the MJKL + anti-VEGF group were significantly decreased compared with those in the anti-VEGF group （P<0.05）. ConclusionMJKL combined with anti-VEGF drugs can inhibit the growth of experimental nAMD fibrovascular membrane better than anti-VEGF drugs alone， and the mechanism may be related to inhibiting the participation of macrophages and glial cells in the formation of fibrovascular membrane.

Integrative study of gene expression datasets in retinal samples of Diabetic Retinopathy.

Diabetic Retinopathy is prevalent among patients with uncontrolled hyperglycemia resulting in vision loss. Despite numerous challenges to create a link among these conditions, the characterization of pathological neovascularization causing retinal damage due to the prognosis of early non-proliferative diabetic retinopathy to late proliferative diabetic retinopathy needs deep understanding. In this study, meta-analysis-based integration of gene expression datasets for the fibrovascular membrane of PDR and neural retina of NPDR were compared, to investigate the differentially expressed genes involved in retinal angiogenesis. Human samples with gene expression profiling of the same experiment type and platform with sufficient information for analysis were included in the study. The studies from cell lines and non-human studies, human samples that include serum, cornea, lens, and/or other ocular tissues or fluids, and studies that lack basic information for analysis were excluded. The microarray datasets available in the Gene Expression Omnibus database of the early and late stages in DR were screened to find common gene expression profiles. Using the INMEX bioinformatics tool, significantly upregulated and downregulated genes in the neural retina of Non-Proliferative Diabetic Retinopathy and fibrovascular membrane of Proliferative Diabetic Retinopathy were compared and studied by the combine effect size method. Using the STRING database PPI network, 50 upregulated and 50 downregulated genes were used to find the key candidate genes involved in retinal disease/degeneration in eye/retinal tissues. In the extensive gene expression meta-analysis performed using INMEX bioinformatics tool, overall, 7935 differentially expressed genes were identified and the respective heatmap was created by using the visualization tools of INVEX. STRING database PPI network identified Retinol Binding Protein 3, Neural Retina Leucine Zipper, S-Antigen Visual Arrestin, Peripherin 2, and Aryl Hydrocarbon Receptor Interacting Protein Like-1 to be the most highly ranked hub genes. The newly discovered potential genes related to retinal angiogenesis causing FVM formation in DR may provide insight into the cellular pathogenesis of NPDR to PDR.

Microvascular cells: A special focus on heterogeneity of pericytes in diabetes associated complications.

Pericytes (PC) are microvascular mural cells that make specific cell-to-cell contacts with the endothelial cells (EC). These cells are obligatory constituents of the microvessels including the retinal vasculature and they serve as regulators of vascular development, stabilization, maturation and remodeling. During early stages of diabetic retinopathy (DR), apoptotic loss of PC surrounding the retinal vasculature occurs. This may lead to reduced vessel stability, the onset of EC apoptosis, and subsequent retinal ischemia leading to angiogenesis and eventually, severe vision loss due to late proliferative diabetic retinopathy (PDR). Similarly, diabetic nephropathy (DN) is a chronic kidney disease due to hyperglycemia that particularly affects renal PC. Chronic high blood glucose level causes migration of peritubular PC away from the capillary into the interstitial space, which destabilizes the micro vessels, resulting in microvascular rarefaction. In both diabetes associated complications, the identification of specific biomarkers is necessary to stabilize the PC at an early stage. This review largely covers the importance of PC towards the pathogenesis of diabetes associated complications, and their heterogeneity in healthy and angiogenic vasculature.

Identification of the aberrantly methylated differentially expressed genes in proliferative diabetic retinopathy.

Diabetic retinopathy (DR) is the most common complication of diabetes. Proliferative DR (PDR) is a more advanced stage of DR, which can cause severe impaired vision and even blindness. However, the precise pathological mechanisms of PDR remain unknown. DNA methylation serves an important role in the initiation and progression of numerous types of disease including PDR. The purpose of this study was to identify the aberrantly methylated differentially expressed genes (DEGs) as potential therapeutic targets of PDR. The gene expression microarray dataset GSE60436 and the methylation profiling microarray dataset GSE57362 were used to determine the aberrantly methylated DEGs in PDR, utilizing normal retinas as controls and fibrovascular membranes (FVMs) in patients with PDR as PDR samples. The functional term and signaling pathway enrichment analysis of the selected genes were subsequently performed. In addition, protein-protein interaction (PPI) networks were constructed to determine the hub genes, and the network of transcriptional factor (TF) and target hub genes was also analyzed. In total, 132 hypomethylated genes were found to be upregulated, whereas 172 hypermethylated genes were discovered to be downregulated in PDR. The hypomethylated upregulated genes were found to be enriched in the pathways, such as "cell-substrate adhesion", "adherens junction", "cell adhesion molecule binding" and "extracellular matrix receptor interactions". Meanwhile, the hypermethylated downregulated genes were enriched in the pathways, such as "visual perception", "presynapse" and the "synaptic vesicle cycle". Based on the PPI analysis, a total of eight hub genes were identified: CTGF, SERPINH1, LOX, RBP3, OTX2, RPE65, OPN1SW and NRL. It was hypothesized that the aberrant methylation of these genes might be related to the possible pathophysiology of PDR. An important transcriptional factor, TFDP1, was discovered to share the closest interactions with the hub genes from the gene-TF network. In conclusion, the present study identified an association among DNA methylation and gene expression in PDR using bioinformatics analysis, and identified the hub genes which might be potential methylation-based diagnosis and treatment targets for PDR in the near future.

Upregulated CD200 in pre-retinal proliferative fibrovascular membranes of proliferative diabetic retinopathy patients and its correlation with vascular endothelial growth factor.

OBJECTIVE AND DESIGN: The objective was to determine the expression of CD200 in the pre-retinal proliferative fibrovascular membranes (PFVM) of patients with proliferative diabetic retinopathy (PDR) and to clarify its correlation with vascular endothelial growth factor (VEGF) and corresponding receptors. METHODS: PFVM samples were collected by vitrectomy from 14 patients with PDR, and 11 non-diabetic patients who accepted vitrectomy for idiopathic epiretinal membranes removal. The expression of CD200, VEGF,VEGF-R1 and VEGF-R2 was measured via qPCR and immunofluorescent staining. RESULTS: The mRNA level of CD200 was significantly higher in PDR patients than that in control patients. Meanwhile, CD200 and CD31 were found co-located and statistically associated in PFVM of PDR patients. The mRNA levels of VEGF, VEGF-R1 and VEGF-R2 were also significantly higher in PDR patients. Moreover, statistical association was found between CD200 and VEGF, VEGF-R1 in mRNA levels. But there was no significant correlationship between CD200 and VEGF-R2. CONCLUSIONS: These results suggest a significantly increased expression of CD200 in PFVM of patients with PDR and present a crucial association between CD200 and VEGF-involved pathway. It represents a potential therapy that interfering with CD200 may inhibit the VEFG expression and neovascular formation in PDR patients.

Air-Perfused 23-Gauge Sutureless Diabetic Vitrectomy for Control of Intraoperative Bleeding during Removal of Fibrovascular Membrane.

PURPOSE: To demonstrate the advantages and efficacy of an air-perfused membrane dissection to control intraoperative bleeding in 23-gauge sutureless vitrectomy for proliferative diabetic retinopathy with severe fibrovascular membranes. Meterials and Methods: A prospective, consecutive, interventional case series of 15 eyes that underwent air-perfused diabetic vitrectomy (air vitrectomy group) for removal of the membranes was compared with a retrospective, membrane-matched case series of 10 eyes that underwent conventional diabetic vitrectomy (conventional vitrectomy group). The main outcome measures were real vitrectomy time, intraoperative and postoperative complications, and anatomic and functional successes at the final examination. RESULTS: The incidence of intraoperative retinal tears was 30% (3/10 eyes) in the conventional vitrectomy group and 20% (3/15 eyes) in the air vitrectomy group (p > 0.05). The postoperative complications such as vitreous hemorrhage or tractional retinal detachment were not common in both groups during the 6-month follow-up (p > 0.05). In addition, the final anatomic and functional success rates did not differ significantly between the groups (p > 0.05). However, the vitrectomy time was significantly shorter in the air vitrectomy group (67.0 ± 21.8 min) than in the conventional group (84.6 ± 21.1 min) (p = 0.04). CONCLUSION: Air-perfused vitrectomy showed comparable anatomic and functional success rates and shorter surgical time, compared with conventional vitrectomy in diabetic eyes with severe fibrovascular membranes. We suppose that the shortened surgical time in the air vitrectomy group is related to less intraoperative bleeding and more efficient hemostasis.

Histopathologic evaluation of the anterior segment of eyes enucleated due to glaucoma secondary to primary lens displacement in 13 canine globes.

PURPOSE To describe histologic anterior segment changes in eyes affected with primary lens displacement (PLD) and secondary glaucoma. METHODS Histologic sections stained with H&E from canine eyes enucleated because of PLD and secondary glaucoma were examined. RESULTS Thirteen eyes from 12 patients were evaluated. Four dogs were castrated males and eight spayed females. Median age was 8 years of age (range 3-13). Breeds included seven terriers and five other breeds. All eyes examined demonstrated varying degrees of inflammation involving the iris and cleft. Mononuclear and melanophagic infiltration of the cleft was found in all specimens. Four globes also showed polymorphonuclear infiltrate. Pre-iridal fibrovascular membranes were clearly identified in 10 of 13 eyes. Total inflammatory score was significantly greater in all globes examined compared with an age-matched group of normal dogs. The posterior pigmented iris epithelium demonstrated a consistent pattern of hyperplasia and/or hypertrophy and cystic degeneration, more prominent in the more central regions. In some cases, hyperplasia was of greatest severity in the mid-iris and associated with thinning or flattening of the pupillary region. CONCLUSIONS These results suggest that lens instability may be associated with chronic inflammation and secondary glaucoma. Mechanical irritation from an unstable lens may result in hypertrophy and/or hyperplasia of the posterior pigmented iris epithelium and subsequent cellular exfoliation and release of melanin. An inflammatory reaction directly or indirectly related to melanin release may obstruct the outflow pathways ultimately leading to glaucoma and loss of vision. Use of topical steroids may be warranted in dogs with PLD.

Glaucoma associated with uveal cysts and goniodysgenesis in American Bulldogs: a case series.

We present a series of three American Bulldogs with clinical signs of glaucoma and intraocular inflammation accompanied by bilateral uveal cysts and abnormal gonioscopic findings. All dogs proved refractory to medical management and were enucleated. Histopathologic findings were similar in all three and included significant preiridal fibrovascular membranes and mononuclear inflammatory infiltrates in the anterior uvea. On microscopic evaluation, cysts appeared to arise primarily from the ciliary body and iridociliary sulcus, with smaller cysts also budding from the posterior iris. Pigment dispersion was variable but consistent, involving deposition of a small number of pigment-laden cells in the dependent trabecular meshwork. Cataract formation was not noted. Glaucoma associated with uveal cysts has been described previously in Golden Retrievers and Great Danes, although clinical and histopathologic findings in those breeds are not identical to those described here. American Bulldogs with uveal cysts should have gonioscopy performed and should be monitored carefully for signs of increased intraocular pressure and intraocular inflammation. Furthermore, documentation of cyst-associated glaucoma in a third breed suggests clinicians should exercise caution in dismissing uveal cysts in dogs as incidental findings.

A Case of Anterior Fibrovascular Membrane After Intraocular Lens Implantation in Congenital Aniridia

PURPOSE: To report a case of an anterior fibrovascular membrane following cataract extraction and intraocular lens implantation in a patient with congenital aniridia. CASE SUMMARY: A 13-year-old girl presented with congenital aniridia and cataracts in both eyes. She underwent cataract extraction by phacoemulcification with intraocular lens implantation. Six months after cataract surgery, a progressive anterior chamber fibrovascular membrane was noted in both intraocular lens and rudimentary iris. Surgical excision of the fibrovascular membrane was performed, but there was recurrence after five weeks in both eyes. Subsequent surgical intervention on both eyes involved intraocular lens explantation combined with membranectomy to prevent recurrence and phthisis. Surgical findings indicated that the fibrovascular membrane involved the retrolenticular space, and histopathological evidence indicated that the extensive fibrotic tissue originated from the root of the rudimentary iris. CONCLUSIONS: Patients with congenital aniridia should be monitored carefully for the development of intraocular fibrosis after intraocular lens implantation. If a fibrovascular membrane is noted, early surgical intervention is recommended, and the explantation of the intraocular lens should be considered during surgical intervention to prevent recurrence and complications.