[Surgical Treatment for Idiopathic Epiretinal Membrane]. / Chirurgická liecba idiopatických epiretinálnych membrán.

AIM: To assess effectiveness of surgical treatment for idiopathic epiretinal membrane. MATERIAL AND METHODS: Retrospective study included on 44 eyes out of 46 patients operated for idiopathic ERM in OFTAL Zvolen with a 20G PPV (32 patients) and posterior vitreous membrane ablation and 23G PPV (14 patients) from August 2008 to December 2014. After the extraction of epiretinal membrane, a peeling of ILM has been implemented following its Blue Membrane identification. Mean follow-up time was 18 months. RESULTS: Best corrected visual acuity (BCVA) before the surgery was 0.37 (SD 0.15) whereas post-surgery indicated 0.63 (SD 0.25). In 35 eyes (76.1%) was BCVA after the surgery 0,5 and better and in 2 eyes (4.3%) was BCVA 0,16 and worse. 29 eyes (63.0%) acquired 2 and more rows. BCVA improved in 40 eyes (87.0%) and remained the same in 3 eyes (6.5%). Degeneration of BCVA in 3 eyes (6.5%) was due to retinal detachment in one case, to retinal pigment epithelium (RPE) atrophy in the second case and to ischemic optic nerve head atrophy in the last case. According to OCT, the average mean of foveal thickness before the surgery was 496 (SD 88) µm and decreased to 356 (SD 59) µm after the surgery (thus average reduction of 140 µm). In 30 eyes (65.2%), we achieved a reduced foveal thickness of more than 100 µm, in comparison to 15 eyes (32.6%) of less than 100 µm. In no case after the surgery did retinal thickness increase comparing to finding before the surgery. Foveal contour restitution was present in 14 eyes (30.4%). There were no preoperative/ intraoperative complications. In 3 eyes (10.3%) a combined cataract surgery with PPV was performed. Cataract progression was seen in 20 phakic eyes (76.9%) out of 26 where all of them were treated surgically at an average time 13 (3-34) months after the PPV. As postoperative complication shows, a retinal detachment occurred in one eye (2.2%) 5 months after the surgery and in 1 eye (2.2%) a cystoid macular edema turned out as the reason of residual posterior vitreous adhesion. CONCLUSION: PPV with membranectomy and internal limiting membrane peeling is a safe and effective method in idiopathic epiretinal membrane treatment. It leads to a function improvement and foveal thickness reduction in most of the patients diagnosed with IEM. Because phakic eyes conduce cataract progression (76.9%), on older patients with no transparent lens we now perform a combination of surgical operations--pars plana vitrectomy and cataract extraction.

The relationship between glycemia, insulin and oxidative stress in hereditary hypertriglyceridemic rat.

The aim of this study was to determine the effects of insulin infusion on oxidative stress induced by acute changes in glycemia in non-stressed hereditary hypertriglyceridemic rats (hHTG) and Wistar (control) rats. Rats were treated with glucose and either insulin or normal saline infusion for 3 hours followed by 90 min of hyperglycemic (12 mmol/l) and 90 min of euglycemic (6 mmol/l) clamp. Levels of total glutathione (GSH), oxidized glutathione (GSSG) and total antioxidant capacity (AOC) were determined to assess oxidative stress. In steady states of each clamp, glucose infusion rate (GIR) was calculated for evaluation of insulin sensitivity. GIR (mg.kg(-1).min(-1)) was significantly lower in hHTG in comparison with Wistar rats; 25.46 (23.41 - 28.45) vs. 36.30 (27.49 - 50.42) on glycemia 6 mmol/l and 57.18 (50.78 - 60.63) vs. 68.00 (63.61 - 85.92) on glycemia 12 mmol/l. GSH/GSSG ratios were significantly higher in hHTG rats at basal conditions. Further results showed that, unlike in Wistar rats, insulin infusion significantly increases GSH/GSSG ratios in hHTG rats: 10.02 (9.90 - 11.42) vs. 6.01 (5.83 - 6.43) on glycemia 6 mmol/l and 7.42 (7.15 - 7.89) vs. 6.16 (5.74 - 7.05) on glycemia 12 mmol/l. Insulin infusion thus positively influences GSH/GSSG ratio and that way reduces intracellular oxidative stress in insulin-resistant animals.

Hyperinsulinemia and oxidative stress.

The aim of the study was to compare the effect of short-term hyperglycemia and short-term hyperinsulinemia on parameters of oxidative stress in Wistar rats. Twenty male rats (aged 3 months, average weight 325 g) were tested by hyperinsulinemic clamp (100 IU/l) at two different glycemia levels (6 and 12 mmol/l). Further 20 rats were used as a control group infused with normal saline (instead of insulin) and 30 % glucose simultaneously. Measured parameters of oxidative stress were malondialdehyd (MDA), reduced glutathion (GSH) and total antioxidant capacity (AOC). AOC remained unchanged during hyperglycemia and hyperinsulinemia. Malondialdehyde (as a marker of lipid peroxidation) decreased significantly (p<0.05) during the euglycemic hyperinsulinemic clamp, and increased significantly during isolated hyperglycemia without hyperinsulinemia. Reduced glutathion decreased significantly (p<0.05) during hyperglycemia without hyperinsulinemia. These results suggest that the short-term exogenous hyperinsulinemia reduced the production of reactive oxygen species (ROS) during hyperglycemia in an animal model compared with the control group.