Abstract 13131: Vitamin D3 Improves Arterial Stiffness and Decreases Leukocyte Activation Postprandially

Abstract

Introduction: The postprandial phase is considered pro-atherogenic in part due to generalized inflammation by triglyceride-rich lipoproteins. Vitamin D modulates the immune system and its levels correlate with arterial stiffness and cardiovascular disease, but the exact mechanisms remain unknown. We investigated if supplementation of vitamin D3 affects arterial stiffness and leukocyte activation postprandially.

Methods: Healthy volunteers underwent two oral fat loading tests (OFLT) and served as their own control. At 0, 2, 4, 6 and 8 hours the augmentation index (AIx), reflecting vascular elasticity, was measured by pulse wave analysis together with flowcytometric quantification of leukocyte activation markers CD11b, CD66b, CD35 and CD36. After completion of the first OFLT a dose of 100.000 IE of vitamin D3 was administered and a second OFLT was carried out after seven days.

Results: A total of 12 volunteers were included. 25-Hydroxyvitamin D3 levels rose from 63.0±28.8 nmol/l to 98.5±26.8 nmol/l after vitamin D3 supplementation (P<0.001). The postprandial triglyceride response remained unaltered. The AIx showed a horizontal postprandial pattern, but after vitamin D3 supplementation a postprandial decrease in AIx was found, reflecting increased arterial elasticity. Vitamin D3 significantly reduced the AIx at T=6 (12.7±15.4% vs 6.9±13.8%, P=0.03) and also the total area under the postprandial AIx curve (93.1±114.1 au vs 68.6±121.4 au, P=0.04). After vitamin D3, a trend was observed at the postprandial triglyceride peak (T=4) with reduced expressions of CD11b and CD35 on neutrophils (24.01±5.3 au vs 21.1±7.1, P=0.06 and 3.0±1.0 vs 2.7±1.0 au, P=0.08, respectively) and CD11b on monocytes (16.5±2.2 au vs 14.9±2.6 au, P=0.09).

Conclusion: Vitamin D3 increases postprandial arterial elasticity in healthy volunteers, potentially by reducing the expression of endothelial adhesion markers on monocytes and neutrophils.