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The molecular mechanisms behind the rupture of intracranial aneurysms remain obscure. MiRNAs are key regulators of a wide array of biological processes altering protein synthesis by binding to target mRNAs. However, variations in miRNA levels in ruptured aneurysmal wall have not been completely examined. We hypothesized that altered miRNA signature in aneurysmal tissues could potentially provide insight into aneurysm pathophysiology. Using a high-throughput miRNA microarray screening approach, we compared the miRNA expression pattern in aneurysm tissues obtained during surgery from patients with aneurysmal subarachnoid hemorrhage (aSAH) with control tissues (GEO accession number GSE161870). We found that the expression of 70 miRNAs was altered. Expressions of the top 10 miRNA were validated, by qRT-PCR and results were correlated with clinical characteristics of aSAH patients. The level of 10 miRNAs (miR-24-3p, miR-26b-5p, miR-27b-3p, miR-125b-5p, miR-143-3p, miR-145-5p, miR-193a-3p, miR-199a-5p, miR-365a-3p/365b-3p, and miR-497-5p) was signi cantly decreased in patients compared to controls. Expression of miR-125b-5p, miR-143-3p and miR-199a-5p was signi cantly decreased in patients with poor prognosis and vasospasm. The target genes of few miRNAs were enriched in Transforming growth factor-beta (TGF-β) and Mitogen-activated protein kinases (MAPK) pathways. We found signi cant negative correlation between the miRNA and mRNA expression (TGF-β1, TGF-β2, SMAD family member 2 (SMAD2), SMAD family member 4 (SMAD4), MAPK1 and MAPK3) in aneurysm tissues. We suggest that miR-26b, miR-199a, miR-497and miR-365, could target multiple genes in TGF-β and MAPK signaling cascades to in uence in ammatory processes, extracellular matrix and vascular smooth muscle cell degradation and apoptosis, and ultimately cause vessel wall degradation and rupture.

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Background The use of dried blood spots (DBS) for the assay of lysosomal enzymes has facilitated the implementation of pilot studies for newborn screening for lysosomal storage disorders in various developed countries. The aim of the study was to determine the influence of ambient temperature during DBS preparation and storage on lysosomal enzyme activity in a developing, tropical country. Methods Blood samples from 12 healthy subjects collected on a S&S 903 filter paper were dried and stored at different temperatures for different periods of time. Activities of five lysosomal enzymes (acid α‐glucosidase, acid α‐galactosidase, acid β‐glucocerebrosidase, acid sphingomyelinase, and galactocerebrosidase) were determined by tandem mass spectrometric and fluorimetric (acid α‐glucosidase and acid β‐glucocerebrosidase only) assays. Results The mean activities of all five enzymes decreased significantly when DBS was dried at temperatures above 24°C (P<.0001). DBS stored at 4°C, 24°C, 30°C, 37°C, and 45°C for 10 days and more, also showed significant reduction in activities of all five enzymes (P<.0001). Conclusion The results highlight the importance of maintaining the correct ambient temperature during DBS preparation and storage to avoid false positive results when screening for lysosomal storage disorders.