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Long-term changes in the secretion of immunosuppressive adrenal-derived glucocorticoid hormones influence cardiovascular disease risk. Here we determined the consequences of changes in adrenal steroid metabolism for the development of atherosclerotic lesions in mice. Atherosclerosis-susceptible low-density-lipoprotein (LDL) receptor knockout mice were subjected to adrenalectomy (ADX) or a control (SHAM) operation and subsequently fed an atherogenic diet for 4 weeks. Atherogenic diet feeding raised plasma corticosterone levels in SHAM mice, but not adrenalectomized mice, resulting in an 83% lower (P<0.01) corticosterone level in adrenalectomized mice. Adrenalectomy was associated with a respectively 22% and 29% lower plasma level of cholesterol and triglycerides. In contrast, white blood cell counts were increased 2-fold (P<0.01) in adrenalectomized mice, which could be attributed to a significant 2.1- to 2.6-fold rise in lymphocyte (P<0.05) and monocyte (P<0.05) numbers. Probably as a result of the enhanced systemic inflammatory status, adrenalectomy was associated with a higher susceptibility for diet-induced atherosclerosis (321±18×10(3) μm(2) for ADX vs 240±31×10(3) μm(2) for SHAM; P<0.05) not withstanding the lowered cholesterol levels. Restoring adrenocortical steroid secretion - but not adrenal medulla function - and the associated downstream glucocorticoid receptor signaling in adrenalectomized mice through adrenal transplantation induced a reversal of the adrenalectomy-associated rise in white blood cell numbers, plasma monocyte chemoattractant protein 1 (MCP-1) levels, and atherosclerotic lesion development (lesion size in transplanted mice: 258±34×10(3) μm(2); P<0.05 vs ADX). In conclusion, our studies show that adrenal-derived steroids protect against the development of initial atherosclerotic lesions in LDL receptor knockout mice.

Objective The liver is the key organ involved in systemic inflammation, but the relation between hepatic inflammation and atherogenesis is poorly understood. Since nuclear factor-κB (NF-κB) is a central regulator of inflammatory processes, we hypothesized that chronically enhanced hepatic NF-κB activation, through hepatocyte-specific expression of IκB kinase-β (IKKβ) (LIKK), will aggravate atherosclerosis development in APOE*3-Leiden (E3L) mice. Methods and Results E3L.LIKK and E3L control littermates were fed a Western-type diet for 24 weeks. E3L.LIKK mice showed a 2.3-fold increased atherosclerotic lesion area and more advanced atherosclerosis in the aortic root with less segments without atherosclerotic lesions (11 vs. 42%), and more segments with mild (63% vs. 44%) and severe (26% vs. 14 %) lesions. Expression of LIKK did not affect basal levels of inflammatory parameters, but plasma cytokine levels tended to be higher in E3L.LIKK mice after lipopolysaccharide (LPS) administration. E3L.LIKK mice showed transiently increased plasma cholesterol levels, confined to (V)LDL. This transient character resulted in a mild (+17%) increased cumulative plasma cholesterol exposure. Conclusion We conclude that selective activation of NF-κB in hepatocytes considerably promotes atherosclerosis development which is (at least partly) explained by an increased sensitivity to proinflammatory triggers and transiently increased plasma cholesterol levels.

The iminosugar N-(5′-adamantane-1′-yl-methoxy)-pentyl-1-deoxynoijirimycin (AMP-DNM), an inhibitor of glycosphingolipid (GSL) biosynthesis is known to ameliorate diabetes, insulin sensitivity and to prevent liver steatosis in ob/ob mice. Thus far the effect of GSL synthesis inhibition on pre-existing NASH has not yet been assessed. To investigate it, LDLR(−/−) mice were kept on a western-type diet for 12 weeks to induce NASH. Next, the diet was continued for 6 weeks in presence or not of AMP-DNM in the diet. AMP-DNM treated mice showed less liver steatosis, inflammation and fibrosis. Induction of fatty acid beta-oxydation was observed, as well as a reduction of plasma lipids. Our study demonstrates that AMP-DNM treatment is able to significantly correct pre-existing NASH, suggesting that inhibiting GSL synthesis may represent a novel strategy for the treatment of this pathology.