Progress in vitreoretinal surgery for proliferative diabetic retinopathy

Long non-coding ribonucleic acid ATP2B1-AS1 modulates endothelial permeability through regulating the miR-4729-IQGAP2 axis in diabetic retinopathy

AIMS/INTRODUCTION

Mounting evidence shows that long non-coding RNAs (lncRNAs) are important to modulate the biological process of diabetic retinopathy (DR). We aimed to investigate the role of lncRNAs in DR and elucidate the exact mechanism.

MATERIALS AND METHODS

Real-time quantitative polymerase chain reaction was carried out to distinguish the lncRNA ATPase plasma membrane Ca2+ transporting 1 antisense RNA 1 (ATP2B1-AS1) expression in DR patients and HG-treated human retinal endothelial cells (HRECs). Dual-luciferase reporter system was used to verify that ATP2B1-AS1 could act as a microRNA (miR)-4729 sponge, and miR-4729 could bind to 3'UTR of IQ motif-containing GTPase-activating protein 2 (IQGAP2). Cell proliferation assay, wound healing migration assay, transwell assay, tube formation assay and immunofluorescence were used to investigate cell proliferation, migration and angiogenesis in HRECs.

RESULTS

The present results showed that ATP2B1-AS1 was downregulated in DR patients and high-glucose-induced HRECs. In gain- and loss-of-function assays, ATP2B1-AS1 overexpression could significantly reduce cell proliferation, migration, angiogenesis and permeability induced by high glucose in vitro. Additionally, we carried out dual-luciferase reporter experiments to determine that ATP2B1-AS1 could act as a miR-4729 sponge. ATP2B1-AS1 overexpression could rescue miR-4729 mimics and short hairpin RNA-IQGAP2 induced cell proliferation, migration and angiogenesis in HRECs.

CONCLUSIONS

The present study showed that ATP2B1-AS1 acted as a miR-4729 sponge to regulate IQGAP2 reducing high-glucose-induced endothelial dysfunction in DR.

Autophagy: A Novel Pharmacological Target in Diabetic Retinopathy

Autophagy is the major catabolic pathway involved in removing and recycling damaged macromolecules and organelles and several evidences suggest that dysfunctions of this pathway contribute to the onset and progression of central and peripheral neurodegenerative diseases. Diabetic retinopathy (DR) is a serious complication of diabetes mellitus representing the main preventable cause of acquired blindness worldwide. DR has traditionally been considered as a microvascular disease, however this concept has evolved and neurodegeneration and neuroinflammation have emerged as important determinants in the pathogenesis and evolution of the retinal pathology. Here we review the role of autophagy in experimental models of DR and explore the potential of this pathway as a target for alternative therapeutic approaches.

Surgical treatments for fibrous tissue extending to the posterior retina in eyes with familial exudative vitreoretinopathy

PURPOSE

To describe the clinical features and surgical outcomes of macular dragging or tractional retinal detachment that occurred as a result of fibrovascular tissue (FT) progression toward the posterior retina in eyes with familial exudative vitreoretinopathy (FEVR).

METHODS

The medical records of 4 patients (2 girls, 2 boys) with FEVR were reviewed retrospectively.

RESULTS

All 4 patients had retinal dragging or radial retinal folds with FT in the peripheral retina in at least 1 eye at the initial visit. During the follow-up period, all the patients had FT that progressed toward the posterior pole and developed from the peripheral FT, resulting in macular dragging or posterior tractional retinal detachment. Vitrectomy with or without scleral buckling and laser photocoagulation were performed in all 4 cases, with removal of the FT in the posterior pole and segmentation of the FT between the posterior and peripheral FT. The traction resolved postoperatively and the retina extended in all 4 cases.

CONCLUSIONS

In 4 cases with FEVR, the FT developed from the peripheral FT, progressed toward the posterior retina, and generated traction. Vitrectomy with focal removal and segmentation of the FT in the posterior pole might be a good surgical option in such eyes.

Surgical management of diabetic retinopathy

Surgery for late complications of proliferative diabetic retinopathy remains the cornerstone of management even in patients who have received optimal laser photocoagulation and medical therapy. With improvisation in the surgical techniques and development of micro-incision surgical techniques for vitrectomy, the indications for surgical intervention are expanding to include diabetic macular edema with a greater number of patients undergoing early intervention. This review describes the current indications, surgical techniques, adjunctive anti-vascular endothelial growth factor therapy, surgical outcomes, and postoperative complications of pars plana vitrectomy for proliferative diabetic retinopathy and macular edema.

Microplasmin-induced posterior vitreous detachment affects vitreous oxygen levels

PURPOSE

To determine if enzymatic induction of a posterior vitreous detachment (PVD) and/or vitreous liquefaction affects O2 concentration in the vitreous cavity in animals with vascularized and avascular retinal circulations.

METHODS

Either microplasmin or hyaluronidase was injected intravitreally into guinea pigs (avascular retinal circulation), brown Norway rats (vascularized retinal circulation without fovea), or cats (vascularized retinal circulation with fovea) with the contralateral eye used as a control. One to 2 weeks post injection, vitreal oxygen concentration was measured using a highly sensitive, platinum-based fluorophore O2 sensor. In addition, control and microplasmin-injected rats, guinea pigs, and cats were exposed to 100% oxygen and vitreal O2 levels were measured over time. Scanning electron microscopy (SEM) was used to evaluate the vitreoretinal interface for the presence of a PVD.

RESULTS

In animals with a vascularized retinal circulation (brown Norway rats and cats), intravitreal injection of microplasmin with induction of a PVD significantly increased baseline O2 concentration in the vitreous cavity compared to hyaluronidase injected eyes and controls in rats (35, 25, and 23 mm Hg, P < 0.001 and P < 0.001, respectively) and cats (26, 18, and 16 mm Hg, P < 0.01 and P < 0.001, respectively). Interestingly, intravitreal injection of hyaluronidase (vitreous liquefaction without induction of a PVD) did not significantly increase vitreal O2 levels in any of the animal species (P > 0.1). Upon exposure to 100% oxygen by facemask, microplasmin injected animals showed a rapid increase in vitreal oxygen levels compared to hyaluronidase injected animals and controls, indicating that the presence of a PVD allows rapid O2 exchange within the vitreous cavity. Similarly, once O2 was discontinued, the O2 concentration decreased in a similarly rapid rate. SEM showed smooth retinal surfaces in microplasmin-injected cat eyes, indicating the presence of a PVD which was not present in hyaluronidase injected or control eyes.

CONCLUSION

The results suggest that enzymatic-assisted PVD with microplasmin increases vitreal O2 levels and increases the rate of O2 exchange within the vitreous cavity.