Ghrelin improves vascular autophagy in rats with vascular calcification

Backgrounds: This study aimed to investigate whether ghrelin ameliorated vascular calcification (VC) through improving autophagy. Methods: VC model was induced by nicotine plus vitamin D3 in rats and E.-glycerophosphate in vascular smooth muscle cell (VSMC). Calcium deposition was detected by von Kossa staining or alizarin red S staining. ALP activity was also detected. Western blot was used to assess the protein expression. Results: Ghrelin treatment attenuated the elevation of calcium deposition and ALP activity in VC model both in vivo and in vitro. Interesting, the protein levels of autophagy markers, LC3 and beclin1 were significantly upregulated by ghrelin in VC model. An autophagy inhibitor, 3-methyladenine blocks the ameliorative effect of ghrelin on VC Furthermore, protein expressions of phosphate-AMPK were increased by ghrelin treatment both in calcified aorta and VSMC The effect of ghrelin on autophagy induction and VC attenuation was prevented by AMPK inhibitor, compound C Conclusions: Our results suggested that ghrelin improved autophagy through AMPK activation, which was resulted in VC amelioration. These data maybe throw light on prevention and therapy of VC. (C) 2016 Elsevier Inc. All rights reserved.