Metformin Inhibits Vascular Calcification in Female Rat Aortic Smooth Muscle Cells via the AMPK-eNOS-NO Pathway

Abstract

Metformin exhibits diverse protective effects against diabetic complications, such as bone loss. Here, we investigated the effect of metformin on vascular calcification, another type 2 diabetes complication. In female rat aortic smooth muscle cells (RASMCs), we observed that metformin significantly alleviated β-glycerophosphate-induced Ca deposition and alkaline phosphatase activity, corresponding with reduced expression of some specific genes in osteoblast-like cells, including Runx2 and bone morphogenetic protein-2, and positive effects on α-actin expression, a specific marker of smooth muscle cells. Mechanistic analysis showed that phosphorylation levels of both AMP-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS) were increased with NO overproduction. After inhibition of either AMPK or eNOS with the pharmacologic inhibitors, compound C or Nω-Nitro-L-arginine methyl ester, NO production was lowered and metformin-meditated vascular protection against β-glycerophosphate-induced Ca deposition was removed. Our results support that metformin prevents vascular calcification via AMPK-eNOS-NO pathway.

Ablation of Adenosine Monophosphate-Activated Protein Kinase α1 in Vascular Smooth Muscle Cells Promotes Diet-Induced Atherosclerotic Calcification In Vivo

“…28 However, eNOS is majorly expressed in endothelial cell but not in VSMC. 46 Compared with other NOS isoforms, eNOS only produces limited NO.…”

“…26,27 Recent studies further revealed that Runx2 in VSMC is crucial in the development of atherosclerotic calcification in mice. 5 It has been reported that AMPK activation negatively regulates Runx2 expression in VSMC in vitro, 28 but the mechanism is not clear. Here, we report that AMPK in VSMC plays a key role in regulating the initiation and progression of atherosclerotic calcification in vivo via Runx2 small ubiquitin-related modifier (SUMO)ylation and degradation pathway in vivo.…”

The Role of Vascular Calcification in Heart Failure and Cognitive Decline

“…- Metformin is a mainstay medication in diabetes therapy and seems to reduce calcification in a rat model via the AMPK-eNOS-NO pathway by increasing NO production [50]. …”

Renoprotective Effects of Metformin

“…Metformin (250 mg/kg/day, for one week to one month) prevents severe kidney failure, vascular calcification and high bone turnover disease in a rat model for CKD /mineral and bone disorders (adenine administration) [61]. In an in vitro study, metformin had shown a preventive effect on vascular calcification via AMPK-eNOS-NO pathway [62]. …”