Background: The role of microRNA (miRNA)-200b in the pathogenesis of proliferative diabetic retinopathy (PDR) has been studied in diabetic animal models. The aim of this study was to assess miRNA-200b expression in the vitreous of patients with PDR and to determine its correlation with vascular endothelial growth factor (VEGF), one of the pathogenic mechanisms in PDR. Methods: Quantitative reverse transcription polymerase chain reaction was used to measure miRNA-200b expression in the vitreous from 29 eyes with PDR and 30 eyes with idiopathic macular holes (IMH; control group). Vitreous VEGF was measured using an enzyme-linked immunosorbent assay. Results: miRNA-200bexpression was about 5-fold increased in the vitreous samples from eyes with PDR compared with the controls (p ≤ 0.001). Vitreous VEGF expression was also significantly higher in the PDR group than in the IMH group (p ≤ 0.001), but no significant correlation was found between miRNA-200b and VEGF. Conclusion: Both miRNA-200b and VEGF are increased in the vitreous of patients with PDR but in a noncorrelated pattern. miRNA-200b may be involved in the pathogenesis of PDR but through VEGF-independent mechanisms. Further studies are needed to identify the miRNA-200b-targeted genes involved in the pathogenesis of PDR and to examine the potential role of miRNA-200b as a target for PDR treatment.

Objectives. Most developmental processes are under the control of small regulatory RNAs called microRNAs (miRNAs). We hypothesize that different fetal developmental processes might be reflected by extracellular miRNAs in maternal plasma and may be utilized as biomarkers for the noninvasive prenatal diagnosis of chromosomal aneuploidies. In this proof-of-concept study, we report on the identification of extracellular miRNAs in maternal plasma of Down syndrome (DS) pregnancies. Methods. Using high-throughput quantitative PCR (HT-qPCR), 1043 miRNAs were investigated in maternal plasma via comparison of seven DS pregnancies with age and fetal sex matched controls. Results. Six hundred and ninety-five miRNAs were identified. Thirty-six significantly differentially expressed mature miRNAs were identified as potential biomarkers. Hierarchical cluster analysis of these miRNAs resulted in the clear discrimination of DS from euploid pregnancies. Gene targets of the differentially expressed miRNAs were enriched in signaling pathways such as mucin type-O-glycans, ECM-receptor interactions, TGF-beta, and endocytosis, which have been previously associated with DS. Conclusions. miRNAs are promising and stable biomarkers for a broad range of diseases and may allow a reliable, cost-efficient diagnostic tool for the noninvasive prenatal diagnosis of DS.

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Sickle cell haemoglobinopathy is a genetic disorder caused by the presence of haemoglobin S (HbS) including sickle cell disease (SCD) (sickle cell anemia, HbS/β -thalassaemia and HbSC disease) and sickle cell trait. In Siwa Oasis, most remote oasis town in Egypt, the prevalence rate of sickle cell haemoglobinopathy is approaching 20%. The 1 polymorphism was reported to increase the HbF level ameliorating the severity of the SCD. The present study aims mainly to investigate the genotype frequency of -158Gγ (C→T) Xmn1 polymorphism in Siwa Oasis, Egypt and to study, if possible, any association with increased HbF expression. This study was performed on 62 sickle cell carriers (AS), three cases of sickle cell anaemia (SS) detected during a screening programme conducted on primary school children in Siwa Oasis by Alexandria Faculty of Medicine in 2011-2012. Sixty-five age-matched and sex-matched healthy controls (AA) were included. All enrolled children were subjected to PCR-RFLP for the detection of -158Gγ (C→T) Xmn1 polymorphism using the Xmn1 restriction enzyme. Genotyping of the -158Gγ (CvT) Xmn1 polymorphism revealed that among AS, 85.5% were homozygous for the wild-type allele (CC) and 14.5% were heterozygous (CT). However, among SS, two cases were homozygous for the wild-type allele (CC) and one case was heterozygous (CT). The genotype frequencies among AA were 83.1% homozygous for the wild-type allele (CC) and 16.9% heterozygous (CT). None of the studied cases or controls was homozygous for the mutant allele (TT). Among both AS and AA, there was no significant difference between the wild-type and heterozygous genotypes regarding HbF level. Studying genotype frequency of the1 γG globin polymorphism (-158C>T ) in Siwa Oasis, Egypt can be considered as a starting point for further research targeting this community sector. However, in our studied cohort, there were only three sickle cell anaemia patients. Further, none of the tested cases or controls was found to be homozygous for the mutant allele (TT). In the absence of any homozygous genotype for the mutant allele (TT) in the studied cohort, any reasonable conclusion on the effect of polymorphism on increase in HbF could not be established. Further studies with a larger sample size are needed for better understanding of the possible association.