Diabetes Converts Arterial Regulation by Perivascular Adipose Tissue From Relaxation Into H2O2-Mediated Contraction

This study aims to reveal the reason for the increased force of 5-hydroxytryptamine-induced contraction of endotheliumdenuded skeletal muscle arteries of diabetic rats in the presence of perivascular adipose tissue (PVAT). Our data on rat gracilis arteries show that i) PVAT of skeletal muscle arteries of healthy and diabetic rats releases hydrogen peroxide (H2O2), ii) higher concentrations of 5-hydroxytryptamine increase the production of H2O2 in PVAT; iii) an enhanced PVAT production of H2O2 is the main, if not the only, reason for the sensitization of arterial contraction to 5-hydroxytriptamine-induced contraction in diabetes and iv) endothelium antagonizes the effect of PVATderived H2O2

Subsets of T regulatory cells in patients with IgE-mediated allergy

Background. It is presently known that several subsets of T-regulatory (Treg) cells, both natural and inducible maintain tolerance to environmental allergens. But the relative importance of distinct phenotypically defined Treg subsets for the clinical manifestations of IgE-mediated allergy has not been elucidated yet.The aim of the study was to investigate the phenotype and number of different Treg subpopulations from patients with IgE-mediated allergy compared with healthy non-allergic individuals.Materials and methods. A group of 20 patients with clinically manifested IgE allergy and a group of 10 healthy no allergic controls were included in the study. Peripheral blood samples were taken after informed consent. Percentage and absolute count (AC) of the following regulatory subsets: naive (CD45RO-FoxP3lo), memory (RO+FoxP3+), effector (Treg eff, RO+FoxP3hi), induced (CD39+CD134+), Thl7/Treg (CD196+FoxP3+CD4Treg); Tr1 (IL-10+FoxP3-), were determined using standard 8-parameter flow cytometry (BD FACSCanto II).Results and discussion. The share and AC of FoxP3+CD4 Treg was significantly decreased in sensitized patients as compared to controls (mean 0,6% vs. 3,3%, p<0.05 and 8,7 vs. 55 cells/μl p<0.001). In addition, a significantly decreased level of Tr1 cells was observed in the patients with allergy, 0,4% vs. 2,1 % in healthy controls (p<0,05) as well for subset of Thl7/Treg (mean 7,7% vs. 28,4% in healthy persons, p<0.01).Conclusion. The significantly decreased number of FoxP3+CD4 Treg as well as periphery induced Tr1 and Thl7/Treg cells in patients with respiratory allergy lead to dysregulation and loss of peripheral immune tolerance, which is the pathophysiological basis for development of widely spread allergic diseases like allergic rhinitis and bronchial asthma