D‐carnosine octylester attenuates atherosclerosis and renal disease in ApoE null mice fed a Western diet through reduction of carbonyl stress and inflammation

Abstract

BACKGROUND AND PURPOSE Lipoxidation‐derived reactive carbonyl species (RCS) such as 4‐hydroxy‐2‐nonenal (HNE) react with proteins to form advanced lipoxidation end products (ALEs), which have been implicated in both atherosclerosis and renal disease. L‐carnosine acts as an endogenous HNE scavenger, but it is rapidly inactivated by carnosinase. This study aimed at assessing the effect of the carnosinase‐resistant, D‐carnosine, on HNE‐induced cellular injury and of its bioavailable prodrug D‐carnosine octylester on experimental atherosclerosis and renal disease. EXPERIMENTAL APPROACH Vascular smooth muscle cells (VSMCs) were exposed to HNE or H2O2 plus D‐carnosine. ApoE null mice fed a Western, pro‐atherogenic diet were treated with D‐carnosine octylester for 12 weeks. KEY RESULTS In vitro, D‐carnosine attenuated the effect of HNE, but not of H2O2, on VSMCs. In vivo, D‐carnosine octylester‐treated mice showed reduced lesion area and a more stable plaque phenotype compared with untreated animals, with reduced foam cell accumulation, inflammation and apoptosis and increased clearance of apoptotic bodies and collagen deposition, resulting in decreased necrotic core formation. Likewise, renal lesions were attenuated in D‐carnosine octylester‐treated versus untreated mice, with lower inflammation, apoptosis and fibrosis. This was associated with increased urinary levels of HNE‐carnosine adducts and reduced protein carbonylation, circulating and tissue ALEs, expression of receptors for these products, and systemic and tissue oxidative stress. CONCLUSIONS AND IMPLICATIONS These data indicate RCS quenching with a D‐carnosine ester was highly effective in attenuating experimental atherosclerosis and renal disease by reducing carbonyl stress and inflammation and that this may represent a promising therapeutic strategy in humans.

Aerobic and resistance training do not influence plasma carnosinase content or activity in type 2 diabetes

“…Several studies in rodents have recently reported protective effects of carnosine administration on dyslipidemia [lipid profile in plasma (3,25), cholesterol levels in heart and liver (21,25), atherosclerosis (23)] and blood pressure (3). In contrast to rodents, humans have the enzyme plasma carnosinase, and as we confirm in this study, its activity is highly variable between individuals.…”

“…Finally, carnosine supplementation in streptozotocin-induced diabetic and dyslipidemic Balb/cA mice reduces triglyceride and cholesterol levels in heart and liver (21). The latter findings have been confirmed and extended in several other animal models of metabolic diseases (3,23,25). Whether the protective effects of carnosine ingestion in rodents can be translated to humans is not known, because rodents, unlike humans, have no carnosinase in their plasma (18).…”

Protection from diabetes-induced atherosclerosis and renal disease by d-carnosine-octylester: effects of early vs late inhibition of advanced glycation end-products in Apoe-null mice

“…Serum levels of isoprostane 8-epiprostaglandin (PG) F 2α were assessed using an ELISA kit (Cayman, Ann Arbor, MI, USA) and those of AGEs were measured by a competitive ELISA technique [17,19,20]. Serum and urine creatinine levels were measured by HPLC and proteinuria and albuminuria were assessed using the Bradford dye-binding protein assay kit (Pierce, Rockford, IL, USA) and the Mouse Albumin ELISA kit (Bethyl, Montgomery, TX, USA), respectively, and results were normalised to urine creatinine concentration [17,20].…”

“…Morphology/morphometry For the assessment of atherosclerotic lesions [17,19], the extent of lipid accumulation was evaluated in en face preparations after staining with Oil Red O. Lesion area was quantified at the aortic sinus and BCA level after staining with Oil Red O and the Weigert-van Gieson method for elastic and collagen fibres [21], respectively. Five cryosections of aortic sinus (10 μm thick, every other section) and four sections (5 μm thick) at 200, 400, 600 and 800 μm from the branching point of the BCA were evaluated.…”

“…Unfortunately, it has a short half-life in humans due to its rapid inactivation by serum and tissue carnosinase [15]. We have recently shown that a bioavailable pro-drug of the carnosinase-resistant D-carnosine, D-carnosine-octylester (DCO) [16], is highly effective in attenuating experimental atherosclerosis and renal disease induced by high-fat diet in Apoe-null mice by reducing carbonyl stress and inflammation [17].…”