Abstract 408: Endothelin-1 and Vitamin D3 Potentiated Calcification and Outward Vascular Remodeling in Leptin-deficient ob/ob Mice
Vascular remodeling, which is an adaptive response of the vessel to specific stimuli has a pivotal role in cardiovascular disease, such as aneurysm formation. In that scope, serum endothelin-1 (ET-1) which is increased in diabetic patients, may contribute to atherosclerosis and aneurysm development. We hypothesized that leptin-deficient ob/ob mice may demonstrate an exaggerated vascular remodeling associated with vascular calcification after Vitamin D3 in vivo. We further investigated the role of ET-1 in vascular smooth muscle cells (SMC) osteochondrogenic differentiation and calcification in vitro. We used leptin-deficient (obob, n=12) and C57BL/6 mice (C57, n=12) injected with saline (Cont) or Vitamin D3 8x104IU (VitD) i.p. daily for 14 days. Results are shown as Mean±SEM and considered statistically significant if p≤.05 by ANOVA. Aorta from ob/obVitD increased both external and internal elastic lamina circumferential length (3478±269.7μm and 3186±262.6μm) versus (vs.) ob/obCont (2841±74.73μm and 2657±71.37μm) vs. C57VitD (2611±39.62μm and 2333±41.79μm) and vs. C57Cont (2569±164.6μm and 2351±167.7μm), thus characterizing outward vascular remodeling. We found that vascular calcification area strongly correlated with increased total vessel area (r2=0.8, p=0.003). We also incubated primary SMC isolated either from obob or from C57 aorta without (Cont) or with ET-1 50nM (ET) for 0-72h. ObobET SMC increased calcification vs. obobCont (1,69±0.025 vs. 1.03±0.03) after 14 days p<.05, n=3 and C57ET did not calcify (0.97±0.02 vs. C57Cont 1±0.05), p=NS. Concomitantly, obobET SMC increased osteochondrogenic differentiation, by modulating RUNX2 (1.23±0.03 vs. obobCont 1±0.01, p<.05 n=3) after 48h, which did not occur in C57. Furthermore, ERk1/2 dephosphorylation peaked after 30min in C57ET in comparison to 60min in obobET SMC. Concurrently, VitD increased both ETA and ETB receptor (4.00±1.04 and 4.25±1.25) in obob aorta vs. paired control in vivo. Nevertheless, C57VitD increased ETA receptor mRNA expression (5.44±1.08) only. In conclusion, we uncovered signaling pathways that may connect Vitamin D and ET-1 calcifying effect to induce excessive outward remodeling in type 2 diabetes.
Author Disclosures: L.S. Carmo: None. Y.E. Almeida: None. M.C.C. Andrade: None. E.F. Silva: None. M. Liberman: None.
- © 2016 by American Heart Association, Inc.