Pioglitazone Prevents Capillary Rarefaction in Streptozotocin-Diabetic Rats Independently of Glucose Control and Vascular Endothelial Growth Factor Expression

Background/Aims: Reduction of capillary network density occurs early in the development of metabolic syndrome and may be relevant for the precipitation of diabetes. Agonists of the peroxisome proliferator-activated receptor (PPAR)-gamma transcription factor are vasculoprotective, but their capacity for structural preservation of the microcirculation is unclear. Methods: Male Wistar rats were rendered diabetic by streptozotocin and treated with pioglitazone in chow for up to 12 weeks. Capillary density was determined in heart and skeletal muscle after platelet endothelial cell adhesion molecule-1 (PECAM-1) immunostaining. Hallmarks of apoptosis and angiogenesis were determined. Results: Capillary density deteriorated progressively in the presence of hyperglycemia (from 971/mm(2) to 475/mm(2) in quadriceps muscle during 13 weeks). Pioglitazone did not influence plasma glucose, left ventricular weight, or body weight but nearly doubled absolute and relative capillary densities compared to untreated controls (1.2 vs. 0.6 capillaries/myocyte in heart and 1.5 vs. 0.9 capillaries/myocyte in quadriceps muscle) after 13 weeks of diabetes. No antiapoptotic or angiogenic influence of pioglitazone was detected while a reduced expression of hypoxia-inducible factor-3 alpha and PPAR coactivator-1 alpha (PGC-1 alpha) mRNA as well as vascular endothelial growth factor (VEGF) protein possibly occurred as a consequence of improved vascularization. Conclusion: Pioglitazone preserves microvascular structure in diabetes independently of improvements in glycemic control and by a mechanism unrelated to VEGF-mediated angiogenesis. Copyright (C) 2012 S. Karger AG, Base

Evidence for an association between migraine and the hypocretin receptor 1 gene

The aim of our study was to investigate whether genetic variants in the hypocretin receptor 1 (HCRTR1) gene could modify the occurrence and the clinical features of migraine. Using a case–control strategy we genotyped 384 migraine patients and 259 controls for three SNPs in the HCRTR1 gene. Genotypic and allelic frequencies of the rs2271933 non-synonymous polymorphism resulted different (χ2 = 9.872, p = 0.007; χ2 = 8.108, p = 0.004) between migraineurs and controls. The carriage of the A allele was associated with an increased migraine risk (OR 1.42, 95% CI 1.11–1.81). When we divided the migraine patients into different subgroups, the difference reached the level of statistical significance only in migraine without aura. The different genotypes had no significant effect on the examined clinical characteristics of the disease. In conclusion, our data supports the hypothesis that the HCRTR1 gene could represent a genetic susceptibility factor for migraine without aura and suggests that the hypocretin system may have a role in the pathophysiology of migraine