Endocrine Abstracts

Objective: higher aldosterone (aldo) levels are associated with increased risk of cardiovascular ischemic events and mortality. It has been demonstrated that aldo accelerates the development of aterosclerosis in apolipoprotein E knockout mice (ApoE KO). Ketogenic diet (KD) positively impacts several cardiovascular risk factors, yet its effect on atherosclerosis, is elusive. We hypothesize that, KD protects from development of atherosclerotic plaques in ApeE KO mice, a murine model of atherosclerosis.

Methods: eight-week-old male ApoE KO mice were fed an ad libitum KD (90.5-fat, 0.4-carbohydrate, 9.1-protein; n=12) or a moderate high fat diet (HFD) (42-fat, 42.7-carbohydrate, 15.2-protein; n=12) and treated with aldo (6 μg/mouse per day) or vehicle through osmotic mini-pumps. Cholesterol content was comparable in KD and HFD. After 4 weeks of treatment, intraperitoneal glucose tolerance test was performed, and peripheral blood samples were collected and used to quantify beta-hydroxybutyrate (OH-But). At the endpoint, mice were euthanized and their cryosections of embedded aortic root were used to quantify the atherosclerotic plaque size, lipid and collagen content in all experimental groups. Vascular inflammation was assesed in speciments of thoracic aorta trough mRNA analisys of pro-inflammatory (ICAM-1, VCAM-1, IL-6, TNF-α and MCP-1) and anti-inflammatory (Arg-1, RETNLA, CCL5) genes.

Results: in ApoE KO mice treated with aldo, KD determined a significant improvements in glucose tolerance compared to mice fed a HFD without any significant effect on body weight. OH-But levels were always significantly higher in KD-mice than in AD-mice, confirming nutritional ketosis in KD-mice. Histological sections of aortic root showed that aldo treatment determined a significant increase in atherosclerotic plaque size and lipid content in HFD-mice. Such effects were significantly reduced in KD mice, suggesting a positive impact of ketosis in the prevention of atherosclerosis development. Plaque fibrosis, as measured by collagen content, did not differ among treatment groups. Finally, we observed a significant reduction in vascular inflammatory markers in KD-mice, when compared to HFD-mice. In particular, KD determined a significant reduction of gene expression of pro-inflammatory markers (ICAM-1, VCAM-1, IL-6, TNF-α and MCP-1) with the concomitant up-regulation of anti-inflammatory markers (Arg-1, RETNLA, CCL5), compared to AD.

Conclusion: the present study identifies KD as a potential non-pharmacological approach to prevent the development of atherosclerotic disease in subjects with high cardiovascular risk. Indeed, we demonstrated that KD determines decreased vascular inflammation and reduced atherosclerotic lesions in ApoE KO mice.