An Association between MicroRNA-21 Expression and Vitamin D Deficiency in Coronary Artery Disease

Atherosclerosis-related cardiovascular disease and osteoporosis (OP) occur concurrently and may share a common pathogenesis. Aberrant expression of miR-21 and vitamin D deficiency have been independently linked to the pathogenesis of atherosclerosis and OP.

To examine the relationship between miR-21 expression and vitamin D in aorta and bone in atherosclerotic disease.

Aorta, internal mammary artery (IMA) and sternal bone samples were collected from patients undergoing coronary artery bypass graft (CABG) surgery. Bone density was measured by dual x-ray absorbtiometry (DXA). MiR-21 was quantified using a two-step reverse transcription-polymerase chain reaction.

Ten patients were included for analysis; 5 were vitamin D deficient (<25nmol/L). MiR-21 was expressed at a greater level in aorta compared with the IMA (p = 0.003), and sternal bone (p = 0.002). Expression of miR-21 between the IMA and bone was similar (p = 0.7). A positive correlation between the magnitude of difference (fold-difference) of miR-21 expression between aorta and IMA and CRP (correlation coefficient 0.9, p = 0.009) was found. Vitamin D deficient patients had greater expression of miR-21 in aorta compared with non-deficient patients (p = 0.03). Increasing CRP and vitamin D deficiency were independent predictors of miR-21 expression in aorta. The lower the difference in miR-21 expression between aorta and bone, the lower the bone density.

In atherosclerosis, miR-21 is increased in the aorta and associated with vitamin D deficiency. Vitamin D deficiency may influence aberrant miR-21 expression in vasculature and bone contributing to the concurrent development of atherosclerosis and osteoporosis.