Elevation of miR-221 and -222 in the internal mammary arteries of diabetic subjects and normalization with metformin

Mol Cell Endocrinol. 2013 Jul 15;374(1-2):125-9. doi: 10.1016/j.mce.2013.04.019. Epub 2013 May 3.


Diabetes is a major risk factor for cardiovascular disease and is associated with increased intimal thickening and accelerated vascular smooth muscle cell (VSMC) proliferation. We measured the expression of two microRNAs that promote intimal thickening, miR-221/222, and mRNA encoding a downstream target, p27(Kip1), in internal mammary artery (IMA) segments collected from 37 subjects undergoing coronary artery bypass grafting. The segments were stratified into three groups: non-diabetic subjects (ND), diabetic subjects not on metformin (DMMet-), and diabetic subjects on metformin (DMMet+). The DMMet- group exhibited a significant increase in miR-221/222 and decrease in p27(Kip1) mRNA compared to both the ND and DMMet+ groups. miR-221/222 levels inversely correlated with metformin dose. VSMCs isolated from the IMAs of the DMMet- group proliferate at a faster rate than those of the ND and DMMet+ groups. Further studies into the importance of miR-221/222 in the increased intimal thickening observed in diabetic subjects is warranted.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biopsy
  • Cardiovascular Diseases / complications
  • Cardiovascular Diseases / drug therapy
  • Cardiovascular Diseases / genetics*
  • Cardiovascular Diseases / surgery
  • Coronary Artery Bypass
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / drug therapy
  • Diabetes Mellitus, Type 2 / genetics*
  • Diabetes Mellitus, Type 2 / surgery
  • Female
  • Gene Expression Regulation
  • Humans
  • Hypoglycemic Agents / pharmacology*
  • Male
  • Mammary Arteries / metabolism
  • Mammary Arteries / pathology
  • Mammary Arteries / surgery
  • Metformin / pharmacology*
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Middle Aged
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / metabolism*
  • Muscle, Smooth, Vascular / pathology
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / metabolism*
  • Myocytes, Smooth Muscle / pathology
  • Primary Cell Culture


  • Hypoglycemic Agents
  • MIRN221 microRNA, human
  • MIRN222 microRNA, human
  • MicroRNAs
  • Metformin