Background and purpose MicroRNAs (miRNAs) are small non‐coding RNAs that regulate gene expression. MiRNA‐126 and miRNA‐146a have been described as having abnormal expressions in diabetic retinopathy (DR) patients. Polymorphisms in genes codifying miRNAs (miRSNPs) may alter the expression of the corresponding miRNA and, thus, interfere with susceptibility to DR. Therefore, miRSNPs in miR‐126 and miR‐146a genes could be associated with DR susceptibility. The purpose of this study was to investigate the association between miR‐126 rs4636297 (G/A) and miR‐146a rs2910164 (G/C) miRSNPs and DR. Methods This case–control study included 195 type 1 diabetes mellitus (T1DM) patients with DR (cases) and 215 patients without DR and with ≥10 years of T1DM (controls). MiRSNPs were genotyped by real‐time PCR. Results Genotype distributions of two analysed miRSNPs were in Hardy–Weinberg equilibrium in controls (p > 0.050). Frequencies of the miR‐126 rs4636297 miRSNP were not significantly different between case and control groups (p = 0.169). However, after adjustment for age, glycated haemoglobin, triglycerides, estimated glomerular filtration rate and ethnicity, the A allele of this miRSNP was associated with protection for DR under additive [OR: 0.444 (95% CI: 0.211–0.936), p = 0.033] and dominant [OR: 0.512 (95% CI: 0.303–0.865), p = 0.012] inheritance models. Genotype and allele frequencies of miR‐146a rs2910164 miRSNP did not differ between groups (p = 0.368 and p = 0.957), and this polymorphism was not associated with DR when assuming different inheritance models. Conclusion Our results suggest an association between the A allele of miR‐126 rs4636297 miRSNP and protection for DR in a Southern Brazilian population.

ObjectiveThe present study analyzed the quality of bovine ovarian tissue after vitrification in a metal closed chamber, in terms of putative changes in tissue viability (lactate dehydrogenase -LDH- release), anti-oxidant defenses, and redox parameters caused by cryopreservation.MethodsSmall and large fragmented bovine ovarian tissue specimens were vitrified in a metal chamber. After rewarming, tissue samples were fixed or cultured for 48 hours. Glutathione (GSH), protein sulfhydryl content, Total Radical Trapping Antioxidant Potential (TRAP), and lactate dehydrogenase were analyzed immediately after rewarming and after tissue culture.ResultsNo changes in antioxidant parameters or viability of rewarmed tissue samples were found immediately or 48h after vitrification. The method of vitrification in a metal closed chamber used in this study preserved the quality of bovine ovarian tissue. Furthermore, our data showed that the size of the tissue specimens did not affect post-vitrification biochemical viability parameters.ConclusionsWe believe that the vitrification methodology employed in the present study is safe and effective, and should be evaluated for use in humans.

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Uncoupling protein 2 (UCP2) decreases reactive oxygen species (ROS). ROS overproduction is a key contributor to the pathogenesis of diabetic kidney disease (DKD). Thus, UCP2 polymorphisms are candidate risk factors for DKD; however, their associations with this complication are still inconclusive. Here, we describe a case-control study and a meta-analysis conducted to investigate the association between UCP2-866G/A and Ins/Del polymorphisms and DKD. The case-control study comprised 385 patients with type 1 diabetes mellitus (T1DM): 223 patients without DKD and 162 with DKD. UCP2-866G/A (rs659366) and Ins/Del polymorphisms were genotyped by real-time PCR and conventional PCR, respectively. For the meta-analysis, a literature search was conducted to identify all studies that investigated associations between UCP2 polymorphisms and DKD in patients with T1DM or type 2 diabetes mellitus. Pooled odds ratios were calculated for different inheritance models. Allele and genotype frequencies of-866G/A and Ins/Del polymorphisms did not differ between T1DM case and control groups. Haplotype frequencies were also similar between groups. Four studies plus the present one were eligible for inclusion in the meta-analysis. In agreement with case-control data, the meta-analysis results showed that the-866G/A and Ins/Del polymorphisms were not associated with DKD. In conclusion, our case-control and meta-analysis studies did not indicate an association between the analyzed UCP2 polymorphisms and DKD.