BENEFICIAL EFFECT OF CYCLIC DISCONTINUATIONS OF ATHEROGENIC FOOD INTAKE ON CORONARY VASODILATOR FUNCTION AND PLASMA HDL LEVELS IN hypercholesterolemic SWINE

Aim: High fat high cholesterol (HC) diet is known to induce atherosclerosis (ATS) in animal models. Dietary factors and timing of atherogenic food delivery may both affect plasma lipoproteins composition. In this study we investigate the effect of periodically discontinued as compared to uninterrupted short term HC diet on lipoproteins levels , vasodilat or response to adenosine and onset of early stage coronary ATS. Methods: Farm pigs were administered either a non atherogenic (C n=7), or a HC diet (HFD n=5) or HC and normal diet every other week (IHFD n=7) for 10 weeks. Coronary angiography, intravascu lar ultrasound (IVUS) and Doppler flow measurements of the left anterior descending artery (LAD) were performed and adenosine - elicited coronary flow reserve (CFR) measured. Lipoproteins plasma composition and histology of coronary samples were obtained. Results: In all HFD and IHFD cases LAD lumen reduction was < 10% at IVUS and angiography with similar early ATS lesions at histology. As compared to HFD, IHFD group showed a similar increase in total and LDL cholesterol but markedly higher HDL levels (p< 0 .0001). CFR was lower in HFD as compared to IHFD and C (p< 0.001), and showed a highly significant positive correlation with HDL values (r = 0.908, p< 0.0001). Conclusions: Intermittent as compared to uninterrupted short term HC diet preserves adenosine - elicited coronary vasodilation and increases plasma HDL/LDL ratio. Coronary microvascular dysfunction at the onset of ATS development is prevented by brief discontinuations of atherogenic diet regimen able to modulate plasma lipids and systemic inflammatio n.