Background: Although remote ischemic preconditioning (RIPC) is shown to preserve kidney function in patients at high risk of contrast-induced acute kidney injury (CI-AKI), the effect in patients at low-moderate risk remains unknown. The preventive effects of RIPC in patients not at high risk of CI-AKI were examined, and biomarkers with anticipated roles in renal protection via RIPC investigated. Methods and Results: Sixty patients who had moderate chronic kidney disease and who underwent angiography were randomly assigned to the control (n=30) or RIPC (intermittent arm ischemia, n=30) group. The baseline characteristics in the 2 groups did not differ significantly. CI-AKI was evaluated by measuring urinary liver-type fatty acid-binding protein (L-FABP). Biomarkers were measured before and 24 and 48h after angiography. Twenty-four hours after angiography, the percent change in urinary L-FABP level in the RIPC group was significantly smaller than in the control group (41.3±15.6 vs. 159±34.1%, P=0.003). L-FABP-based CI-AKI developed in 8 control patients (26.9%) vs. only 2 patients in the RIPC group (7.7%), suggesting that RIPC prevents CI-AKI. Factors contributing to CI-AKI were analyzed. Neither high-sensitivity C-reactive protein nor pentraxine-3 level differed significantly between the 2 groups, while the percent change in asymmetrical dimethy larginine (ADMA) level and blood derivatives of reactive oxidative metabolite levels were significantly smaller in the RIPC group. Conclusions: RIPC alleviates CI-AKI in patients at low-moderate risk. This effect might be mediated partly by decreasing oxidative stress and plasma ADMA level. (Circ J 2013; 77: 3037–3044)

Destabilization of Atg7 mRNA by the CCR4-NOT complex prevents p53-dependent cell death in the heart.

Apelin is an inotropic and cardioprotective peptide that exhibits beneficial effects through activation of the APJ receptor in the pathology of cardiovascular diseases. Apelin induces the expression of angiotensin-converting enzyme 2 (ACE2) in failing hearts, thereby improving heart function in an angiotensin 1–7-dependent manner. Whether apelin antagonizes the over-activation of the renin–angiotensin system in the heart remains elusive. In this study we show that the detrimental effects of angiotensin II (Ang II) were exacerbated in the hearts of aged apelin-gene-deficient mice. Ang II-mediated cardiac dysfunction and hypertrophy were augmented in apelin knockout mice. The loss of apelin increased the ratio of angiotensin-converting enzyme (ACE) to ACE2 expression in the Ang II-stressed hearts, and Ang II-induced cardiac fibrosis was markedly enhanced in apelin knockout mice. mRNA expression of pro-fibrotic genes, such as transforming growth-factor beta (TGF-β) signaling, were significantly upregulated in apelin knockout hearts. Consistently, treatment with the ACE-inhibitor Captopril decreased cardiac contractility in apelin knockout mice. In vitro, apelin ameliorated Ang II-induced TGF-β expression in primary cardiomyocytes, accompanied with reduced hypertrophy. These results provide direct evidence that endogenous apelin plays a crucial role in suppressing Ang II-induced cardiac dysfunction and pathological remodeling.