Sirtuins [sirtuin (SIRT)1-SIRT7] mediate the longevity-promoting effects of calorie restriction in yeast, worms, flies, and mice. Additionally, SIRT3 is the only SIRT analog whose increased expression has been shown to be associated with longevity in humans. The polyphenol resveratrol (RSV) is the first compound discovered able to mimic calorie restriction by stimulating SIRTs. In the present study, we report that RSV activated SIRT3 in cardiac fibroblasts both in vivo and in vitro. Moreover, in wild-type mice, RSV prevented cardiac hypertrophy in response to hypertrophic stimuli. However, this protective effect was not observed in SIRT3 knockout mice. Additionally, the activation of SIRT3 by RSV ameliorated collagen deposition and improved cardiac function. In isolated cardiac fibroblasts, pretreatment with RSV suppressed fibroblast-to-myoblast transformation by inhibiting the transforming growth factor-β/Smad3 pathway. Therefore, these data indicate that the activation of SIRT3 by RSV could ameliorate cardiac fibrosis and improve cardiac function via the transforming growth factor-β/Smad3 pathway.

Cardiac hypertrophy is an adaptive response to pressure, volume stress, and loss of contractile mass from prior infarction. Metabolic changes in cardiac hypertrophy include suppression of fatty acid oxidation and enhancement of glucose utilization, which could result in lipid accumulation in the heart. SIRT3, a mitochondrial NAD+-dependent deacetylase, has been demonstrated to play a crucial role in controlling the acetylation status of many enzymes participating in energy metabolism. However, the role of SIRT3 in the pathogenesis of hypertrophy-related lipid accumulation remains unclear. In this study, hypertrophy-related lipid accumulation was investigated using a mouse cardiac hypertrophy model induced by transverse aortic constriction (TAC). We showed that mice developed heart failure six weeks after TAC. Furthermore, abnormal lipid accumulation and decreased palmitate oxidation rates were observed in the hypertrophic hearts, and these changes were particularly significant in SIRT3-KO mice. We also demonstrated that the short form of SIRT3 was downregulated in wild-type (WT) hypertrophic hearts and that this change was accompanied by a higher acetylation level of long-chain acyl CoA dehydrogenase (LCAD), which is a key enzyme participating in fatty acid oxidation. In addition, SIRT3 may play an essential role in attenuating lipid accumulation in the heart through the deacetylation of LCAD.

Sirt3, a mitochondrial NAD+-dependent histone deacetylase, is the only member proven to promote longevity in mammalian Sirtuin family. The processed short form of Sirt3 has been demonstrated to target many mediators of energy metabolism and mitochondrial stress adaptive program. Autophagy serves as a dynamic recycling mechanism and provides energy or metabolic substrates. Among the mechanisms triggered by cardiac stress, opinions vary as to whether autophagy is a protective or detrimental response. Here, by inducing the Sirt3-knockout mice to myocardial hypertrophy with chronic angiotensin II infusion for four weeks, we determined the role of Sirt3 in myocardial hypertrophy and autophagy. In this study, the Sirt3-knockout mice developed deteriorated cardiac function and impaired autophagy compared to wild-type mice. What's more, the overexpression of Sirt3 by lentivirus transfection attenuated cardiomyocytes hypertrophy by promoting autophagy. We further demonstrated that Sirt3 could bind to FoxO1 and activate its deacetylation. Sequentially, deacetylated FoxO1 translocates to the nucleus where it facilitates downstream E3 ubiquitin ligases such as Muscle RING Finger 1 (MuRF1) and muscle atrophy F-box (MAFbx, Atrogin1). Altogether, these results revealed that Sirt3 activation is essential to improve autophagy flux by reducing the acetylation modification on FoxO1, which in turn alleviates myocardial hypertrophy.

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Our investigation demonstrated that there is a Th17/Treg functional imbalance in patients with unstable carotid atherosclerotic plaques. Th17 cells may promote atherogenesis, while Treg cells may have a protective role against atherosclerosis plaques. An imbalance of Th17/Treg cells may offer a new direction for the treatment of atherosclerosis.

Economy has developed rapidly in China, and the clustering of cardiovascular risk factors in subjects increased remarkably over the past two decades. However, no data are available regarding the temporal prevalence of hyperuricemia and its correlates in this rapidly developing area, especially in the inland area. The cross-sectional survey was based on a random sample of 4,218 residents aged 35-64 years in the Jinan area. Hyperuricemia was defined as serum uric acid ≥ 416 μmol/L in men and ≥ 357 μmol/L in women. Subjects underwent physical examination and fasting blood testing. Complete data were available for analysis from 1,979 men and 2,062 women. The age-adjusted prevalence of hyperuricemia was 6.4 % for men and 2.1 % for women. The prevalence of hyperuricemia was greater in urban (6.7 %) than in rural areas (1.7 %) of Jinan city. Multivariate logistic regression models revealed hyperuricemia associated with hypertriglyceridemia [men: odds ratio (OR) = 6.101, 95 % confidence interval (CI) 4.064-9.159; women: OR = 7.103, 95 % CI 3.578-14.099] and high serum creatinine level (men: OR = 2.603, 95 % CI 1.602-4.230; women: OR = 5.237, 95 % CI 2.667-10.284). Hyperuricemia was also significantly associated with male sex, urban residence, hypertension, obesity, and hypercholesterolemia. Age (1-year increase) was negatively associated with hyperuricemia in men but positively associated with hyperuricemia in women. In conclusion, the prevalence of hyperuricemia is higher in urban than rural areas of Jinan, China. Male sex, urban residence, hypertension, obesity, hypercholesterolemia, hypertriglyceridemia, and high serum creatinine level contributed to hyperuricemia in this population.

2The authors investigated effects of excessive salt intake and potassium supplementation on ambulatory arterial stiffness index (AASI) and endothelin-1 (ET-1) in salt-sensitive and nonsalt-sensitive individuals. AASI and symmetric AASI (s-AASI) were used as indicators of arterial stiffness. Plasma ET-1 levels were used as an index of endothelial function. Chronic salt-loading and potassium supplementation were studied in 155 normotensive to mild hypertensive patients from rural northern China. After 3 days of baseline investigation, participants were maintained sequentially for 7 days each on diets of low salt (51.3 mmol/d), high salt (307.7 mmol/d), and high salt+potassium (60 mmol/d). Ambulatory 24-hour blood pressure (BP) and plasma ET-1 were measured at baseline and on the last 2 days of each intervention. High-salt intervention significantly increased BP, AASI, s-AASI (all P<.001); potassium supplementation reversed increased plasma ET-1 levels. High-salt-induced changes in BP, s-AASI, and plasma ET-1 were greater in salt-sensitive individuals. Potassium supplementation decreased systolic BP and ET-1 to a significantly greater extent in salt-sensitive vs non-salt-sensitive individuals (P<.001). Significant correlations were identified between s-AASI and ET-1 change ratios in response to both high-salt intervention and potassium supplementation (P<.001). Reducing dietary salt and increasing daily potassium improves arterial compliance and ameliorates endothelial dysfunction.

Nanosized Ir catalysts suffer from serious side reactions and poor stability during hydrogenation of substituted nitroaromatics to produce aromatic amines. In this work, core−shell nanostructures with sub-4 nm Ir-CoO x hybrid cores and mesoporous SiO 2 shells were designed and prepared to overcome these problems. The Ir-CoO x hybrid cores were converted from IrCo alloy nanoparticles (NPs) inside SiO 2 through in situ calcination and reduction pretreatments. The SiO 2 mesoporous shells in Ir-CoO x @SiO 2 nanoreactors prevented the agglomeration/sintering of IrCo NPs, while allowing the free reactants and products (big molecules). The synergy between Ir and CoO x species improved H 2 adsorption, thus affecting the reaction rate as well as the selectivity to aromatic amines. As a result, the obtained Ir-CoO x @SiO 2 nanocatalyst showed tremendous improvement in catalytic activity, selectivity, and stability.