Effect of Renin-Angiotensin System Blockers in Acute Myocardial Infarction Patients with Acute Kidney Injury.

INTRODUCTION: Renin-angiotensin system blockers (RASBs) are known to improve mortality after acute myocardial infarction (AMI). However, there remain uncertainties regarding treatment with RASBs after AMI in patients with renal dysfunction and especially in the setting of acute kidney injury (AKI). METHODS: Patients from a multicenter AMI registry undergoing percutaneous coronary intervention in Korea were stratified and analyzed according to the presence of AKI, defined as an increase in serum creatinine levels of ≥0.3 mg/dL or ≥50% increase from baseline during admission, and RASB prescription at discharge. The primary outcome of interest was 5-year all-cause mortality. RESULTS: In total 9,629 patients were selected for initial analysis, of which 2,405 had an episode of AKI. After adjustment using multivariable Cox regression, treatment with RASBs at discharge was associated with decreased all-cause mortality in the entire cohort (hazard ratio [HR] 0.849, confidence interval [CI] 0.753-0.956), but not for the patients with AKI (HR 0.988, CI 0.808-1.208). In subgroup analysis, RASBs reduced all-cause mortality in patients with stage I AKI (HR 0.760, CI 0.584-0.989) but not for stage II and III AKI (HR 1.200, CI 0.899-1.601, interaction p value 0.002). Similar heterogeneities between RASB use and AKI severity were also observed for other clinical outcomes of interest. CONCLUSION: Treatment with RASBs in patients with AMI and concomitant AKI is associated with favorable outcomes in non-severe AKI, but not in severe AKI. Further studies to confirm these results and to develop strategies to minimize the occurrence of adverse effects arising from RASB treatment are needed.

Resistin Regulates Inflammation and Insulin Resistance in Humans via the Endocannabinoid System.

Resistin plays an important role in the pathophysiology of obesity-mediated insulin resistance in mice. However, the biology of resistin in humans is quite different from that in rodents. Therefore, the association between resistin and insulin resistance remains unclear in humans. Here, we tested whether and how the endocannabinoid system (ECS) control circulating peripheral blood mononuclear cells (PBMCs) that produce resistin and infiltrate into the adipose tissue, heart, skeletal muscle, and liver, resulting in inflammation and insulin resistance. Using human PBMCs, we investigate whether the ECS is connected to human resistin. To test whether the ECS regulates inflammation and insulin resistance in vivo, we used 2 animal models such as "humanized" nonobese diabetic/Shi-severe combined immunodeficient interleukin-2Rγ (null) (NOG) mice and "humanized" resistin mouse models, which mimic human body. In human atheromatous plaques, cannabinoid 1 receptor (CB1R)-positive macrophage was colocalized with the resistin expression. In addition, resistin was exclusively expressed in the sorted CB1R-positive cells from human PBMCs. In CB1R-positive cells, endocannabinoid ligands induced resistin expression via the p38-Sp1 pathway. In both mouse models, a high-fat diet increased the accumulation of endocannabinoid ligands in adipose tissue, which recruited the CB1R-positive cells that secrete resistin, leading to adipose tissue inflammation and insulin resistance. This phenomenon was suppressed by CB1R blockade or in resistin knockout mice. Interestingly, this process was accompanied by mitochondrial change that was induced by resistin treatment. These results provide important insights into the ECS-resistin axis, leading to the development of metabolic diseases. Therefore, the regulation of resistin via the CB1R could be a potential therapeutic strategy for cardiometabolic diseases.