Impact of peroxisome proliferator-activated receptor γ on angiotensin II type 1 receptor-mediated insulin sensitivity, vascular inflammation and atherogenesis in hypercholesterolemic mice

Angiotensin I-converting enzyme inhibitory peptide: an emerging candidate for vascular dysfunction therapy

Abnormal vasoconstriction, inflammation, and vascular remodeling can be promoted by angiotensin II (Ang II) in the renin-angiotensin system (RAS), leading to vascular dysfunction diseases such as hypertension and atherosclerosis. Researchers have recently focused on angiotensin I-converting enzyme inhibitory peptides (ACEIPs), that have desirable efficacy in vascular dysfunction therapy due to Ang II reduction by inhibiting ACE activity. Promising methods for the large-scale preparation of ACEIPs include selective enzymatic hydrolysis and microbial fermentation. Thus far, ACEIPs have been widely reported to be hydrolyzed from protein-rich sources, including animals, plants, and marine organisms, while many emerging microorganism-derived ACEIPs are theoretically biosynthesized through the nonribosomal peptide synthase (NRPS) pathway. Notably, vasodilatation, anti-inflammation, and vascular reconstruction reversal of ACEIPs are strongly correlated. However, the related molecular mechanisms underlying signal transduction regulation in vivo remain unclear. We provide a comprehensive update of the ACE-Ang II-G protein-coupled type 1 angiotensin receptor (AT1R) axis signaling and its functional significance for potential translation into therapeutic strategies, particularly targeting AT1R by ACEIPs, as well as specific related signaling pathways. Future studies are expected to verify the biosynthetic regulatory mechanism of ACEIPs via the NRPS pathway, the effect of gut microbiota metabolism on vascular dysfunction and rigorous studies of ACE-Ang II-AT1R signaling pathways mediated by ACEIPs in large animals and humans.

Effects of Statins on Renin-Angiotensin System

Statins, a class of drugs for lowering serum LDL-cholesterol, have attracted attention because of their wide range of pleiotropic effects. An important but often neglected effect of statins is their role in the renin–angiotensin system (RAS) pathway. This pathway plays an integral role in the progression of several diseases including hypertension, heart failure, and renal disease. In this paper, the role of statins in the blockade of different components of this pathway and the underlying mechanisms are reviewed and new therapeutic possibilities of statins are suggested.

C-reactive protein levels predict systolic heart failure and outcome in patients with first ST-elevation myocardial infarction treated with coronary angioplasty

INTRODUCTION

There is growing evidence that inflammation plays a pivotal role in the etiology and progression of atherosclerosis. High C-reactive protein (CRP) levels have been associated with high mortality in patients with acute myocardial infarction (AMI). Furthermore, in animal models CRP has been found to significantly increase infarct size. So there is growing evidence that CRP is not only a marker for cardiovascular disease but also might be pathogenic. The aim of our study was to test the hypothesis that peak CRP levels could predict heart failure (HF) in ST-elevation myocardial infarction (STEMI) patients.

MATERIAL AND METHODS

Eighty-one consecutive patients with STEMI were prospectively enrolled in the study. C-reactive protein concentrations were measured on admission and after 6, 12, 24, 30, 48, 72 and 96 h. We assessed the association between the elevation of CRP, heart failure and cardiovascular mortality following the first 12 months after STEMI.

RESULTS

C-reactive protein levels reached a peak after 48 h. Patients with STEMI and signs of HF showed significantly higher peak CRP levels. We found a positive correlation between maximum CK levels and peak CRP and a negative correlation between left ventricular ejection fraction (EF) and peak CRP. One year total mortality and HF mortality rates were found to be higher in patients with peak CRP > 47.5 mg/l than in those with CRP below that level (p < 0.001).

CONCLUSIONS

Peak CRP levels in STEMI patients predict emergence of HF. Peak CRP is also a strong predictor of global and cardiovascular mortality during the following year after STEMI.

Genetic disruption of multidrug resistance-associated protein 1 improves endothelial function and attenuates atherosclerosis in MRP1-/- LDLr-/- double knockout mice

INTRODUCTION

Multidrug resistance-associated protein 1 (MRP1) is an anion transporter which is implicated in the efflux of the intracellular antioxidant anion glutathione as well as leukotrienes. Pharmacological inhibition of MRP1 exhibits antioxidative and anti-atherosclerotic effects both in vitro and in vivo. However, pharmacological inhibitors of MRP1 lack selectivity, which prompted us to study the in vivo impact of a genetic disruption of MRP1 on endothelial dysfunction, reactive oxygen species formation and atherogenesis in an atherosclerotic mouse model.

MATERIAL AND METHODS

MRP1^-/- LDLr^-/- double knockout mice. were fed a high-fat and cholesterol-rich diet for 7 weeks. Thereafter, endothelial function was assessed in isolated aortic rings. Reactive oxygen species were quantified by L-012 chemiluminescence, and the atherosclerotic plaque burden was measured following oil red O staining.

RESULTS

Endothelium-dependent vasodilation of MRP1^-/- LDLr^-/- double knockout mice was significantly improved compared to MRP1-competent LDLr^-/- single knockout mice (0.56 ±0.06 vs. 0.78 ±0.08; n = 10; p = 0.048). This improvement was accompanied by a significant reduction in reactive oxygen species formation within the aortic tissue (102 ±27 RLU/s/mg vs. 315 ±78 RLU/s/mg, n = 9-11, p = 0.03). Moreover, the atherosclerotic plaque burden of MRP1^-/- LDLr^-/- double knockout mice was significantly reduced (0.06 ±0.01 vs. 0.12 ±0.02; n = 6; p = 0.047). Finally, arterial blood pressure was significantly reduced in MRP1^-/- LDLr^-/- double knockout mice (93 ±5 mm Hg vs. 128 ±4 mm Hg; n = 8-12; p < 0.001).

CONCLUSIONS

Genetic disruption of MRP1 appears to reduce blood pressure and vascular oxidative stress in vivo, which leads to improved endothelial function and a reduced plaque burden in atherosclerotic mice. Therefore, MRP1 might represent a promising therapeutic target to improve endothelial function in patients suffering from atherosclerosis.