Abstract 17594: Eosinophils Are Crucial for Mediating the Anticontractile Capacity of Perivascular Adipose Tissue
Perivascular adipose tissue (PVAT) has an anticontractile effect which is lost in obesity due to inflammation and subsequent changes in secreted adipokines thus providing a link with obesity and cardiovascular complications. We have shown that the presence of M1 macrophages is crucial in this response. Eosinophils maintain M2 macrophage populations and glucose homeostasis. The aim of this study was to investigate the influence of eosinophils on PVAT activity.
Wire myography was used to investigate vascular reactivity of mice with eosinophil deficiency (GATA-F2) or excess (IL5T) and their wildtype (WT) littermates. Reconstitution of eosinophils (30 days) from IL5T splenic homogenates in GATA-F2 mice was also performed to determine whether the eosinophil deficient phenotype could be rescued.
PVAT exerted an anticontractile effect in WT and IL5T mice (WT: P<0.0001 n=14 IL5T: P<0.0001, n=7), but this was absent in GATA-F2 mice (P=0.085, n=14). Reconstitution of eosinophils restored PVAT anticontractile capacity (P<0.001, n=9). There were no significant differences in the contractility of arteries denuded of PVAT. Bioassay experiments confirmed the secretion of a transferable anticontractile factor from WT and IL5T PVAT. Tension changes were significantly impaired in GATA-F2 mice (P=0.0026, n=13). Solution transfer from arteries with PVAT+reconstituted eosinophils restored the PVAT anticontractile effect to levels similar to those in WT (P=0.53, n=6). Bioassays between arteries from different mouse strains demonstrated a significantly reduced change in tension following solution transfer between WT PVAT donor arteries to denuded GATA-F2 arteries (P=0.004, n=7) as well as GATA-F2 donor PVAT arteries to denuded WT arteries (P=0.0482, n=7).All other transfer combinations were not statistically significant from control.
Our data implicate the eosinophil in mediating PVAT function both up and down stream of secreted adipose tissue factor(s) due to alterations at the vascular and PVAT levels. Whether this is via an increase in M2 macrophages or if eosinophils are absent in obesity remains to be elucidated.
- © 2013 by American Heart Association, Inc.