Niacin results in reduced monocyte adhesion in patients with type 2 diabetes mellitus.

BACKGROUND AND AIM: Patients with type 2 diabetes have increased expression of cell adhesion molecules (CAMs). CAMs and monocyte adhesion mediate essential processes in atherogenesis. It remains unclear if monocytes from patients on niacin have reduced adhesion function. METHODS: We studied the variation of monocyte adhesion in patients with type 2 diabetes and low HDL-cholesterol, taking either extended release niacin (Niaspan®, Abbott Laboratories) or controls not on niacin. Biochemical parameters including adiponectin, CAMs and fresh monocytes from whole blood for adhesion assays, were studied at baseline and 12-weeks. RESULTS: Niacin 1500 mg daily raised HDL-cholesterol from 0.8 mmol/l (95% CI: 0.7-0.9) to 0.9 mmol/l (95% CI: 0.8-1.1), p=0.10, and significantly reduced PECAM-1 by 24.9% (95% CI: 10.9-39.0; p<0.05), increased adiponectin by 30.5% (95% CI: 14.1-47.0; p<0.05), with monocyte adhesion reduced by 9.2% (95%CI: 0.7-17.7; p<0.05) in endothelial cells treated in basal conditions, and 7.8% (95% CI: 3.1-12.5; p<0.05) after TNF-α stimulation. CONCLUSIONS: Monocytes isolated from patients on niacin had reduced adhesion to endothelial cells. Our findings suggest niacin has broad range of effects apart from lipid-modification, and these could be important in cardiovascular risk reduction.