Study Shows How Low Vitamin D May Influence Heart Risk

In patients with diabetes, vitamin D associated with decreased formation of foam cells

30 aug 2009-- In people with diabetes, vitamin D may inhibit foam cell creation by reducing acetylated or oxidized low-density lipoprotein (LDL) cholesterol uptake in macrophages, according to research published in the Aug. 25 issue of Circulation.

Jisu Oh, of Washington University in St. Louis, and colleagues analyzed data from macrophages from obese diabetics with hypertension and vitamin D deficiency and four other control groups varying in these factors. Macrophages were cultured in media that contained 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) or that was vitamin D deficient, and then exposed to LDL cholesterol.

The researchers found that, in diabetic patients, 1,25(OH)₂D₃ -- the active form of vitamin D -- suppressed foam cell formation. Deleting the vitamin D receptor in macrophages from patients with diabetes sped up modified LDL-induced foam cell formation.

"In this study, we demonstrate that activation of vitamin D receptor signaling prevents foam cell formation by reducing modified LDL cholesterol uptake in macrophages from diabetic patients. Through suppression of endoplasmic reticulum stress and c-Jun N-terminal kinase activation, 1,25(OH)₂D₃ downregulates two critical scavenger receptors involved in macrophage cholesterol deposition. Impairment of vitamin D receptor signaling confirmed acceleration of foam cell formation in diabetics. Taken together, these results suggest that modulation of vitamin D signaling is a potential therapeutic target to prevent vascular disease progression," the authors write.

Abstract
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