Leptin protects cardiomyocytes from serum-deprivation-induced apoptosis by increasing anti-oxidant defence.

1. Leptin, an important adipose-derived hormone, can be associated with cardiac pathophysiology; however, the role of leptin in cardiomyocyte apoptosis is poorly understood. The present study examines serum-deprivation-induced apoptosis in primary cultured cardiomyocytes treated with leptin. 2. Cardiomyocytes were subjected to serum deprivation in the presence or absence of leptin (5 or 50 nmol/L) for 48 h. Apoptosis was determined by Hoechst 33258 and Annexin V-FITC/propidium iodide dual staining. Cell viability, malondialdehyde (MDA) content, caspase 3 activation, and the expression and enzyme activity of superoxide dismutase (SOD) were measured. Small interference RNA (siRNA) targeting SOD1 and SOD2 were used to knockdown their expression and measure apoptosis. 3. Serum deprivation caused nearly 30% of apoptosis in cardiomyocytes, and an approximately 60% decrease in cell viability. The mRNA levels and the activated form of caspase 3 were greatly increased. In the presence of leptin, the apoptotic rate was reduced to approximately 15%, cell viability was increased and the activation of caspase 3 was partially inhibited. Additionally, the augmented lipid peroxidation (MDA formation) was abolished, and the impaired activities of SOD1 and SOD2 were restored by leptin. The mRNA expression of SOD2, but not SOD1, was stimulated by leptin. Transfection with siRNA that cause deficiency of either SOD1 or SOD2 attenuated the anti-apoptotic effects of leptin. 4. The results suggest that leptin inhibits serum-deprivation-induced apoptosis in cardiomyocytes by activating SOD. The present study outlines the direct actions of leptin in cardiac disorders that are related to elevated leptin levels.

[Nordihydroguaiaretic acid partially inhibits inflammatory responses after focal cerebral ischemia in rats].

The aim of the present study is to investigate the role of nordihydroguaiaretic acid (NDGA) on inflammatory cells accumulation after focal cerebral ischemia and the underlying mechanism. Focal cerebral ischemia was induced by 30 min of middle cerebral artery occlusion (MCAO) followed by 72 h of reperfusion. NDGA (5 and 10 mg/kg) was administered intraperitoneally 30 min, 2, 24, 48 h after reperfusion, respectively. The brain injuries were observed by neurological and histological examination. Endogenous IgG exudation, neutrophils and macrophages/microglia accumulation, and intercellular adhesion molecule-1 (ICAM-1) protein expression were determined by immunohistochemistry 72 h after reperfusion. ICAM-1 mRNA was determined by RT-PCR 72 h after reperfusion. The catalysates of 5-lipoxygenase (5-LOX), leukotriene B4 (LTB4) and cysteinyl leukotrienes (CysLTs), were evaluated by ELISA 3 h after reperfusion. The results showed that NDGA ameliorated neurological dysfunction, decreased infarct volume, and inhibited endogenous IgG exudation, neutrophils infiltration, ICAM-1 mRNA and protein expression 72 h after reperfusion. Moreover, NDGA reduced the levels of LTB4 and CysLTs 3 h after reperfusion. However, NDGA did not reduce the accumulation of macrophages/microglia 72 h after reperfusion. These results suggest that NDGA decreases neutrophil infiltration in the subacute phase of focal cerebral ischemia via inhibiting 5-LOX activation.

Assessment of the association between serum uric acid levels and the incidence of hypertension in nonmetabolic syndrome subjects: A prospective observational study.

The purpose of this study was to examine the association between serum uric acid (sUA) and the incidence of hypertension in nonmetabolic syndrome (non-MetS) subjects.This was a prospective observational study including 23,525 subjects who had been followed up for at least 5 years. A logistic regression model was used to assess independent risk factors associated with hypertension. An area under the receiver operating characteristic curve (auROC) was generated, and a nomogram was developed to assess diagnostic ability of sUA and the sUA-based score.We enrolled 11,642 subjects, and 763 (6.55%) were diagnosed with hypertension at the 5-year follow-up. Subjects were classified into 4 groups based on the sUA quarter. Using Q1 as the reference group, Q2, Q3, and Q4 were found to show a higher risk for the development of hypertension with odds ratio of 1.51 (1.15, 1.98), 1.72 (1.30, 2.27), and 2.27 (1.68, 3.06), respectively (P < .001) after adjusting for other known confounding variables. Interaction analysis showed that there was no significant difference between subgroups stratified on the basis of sex, age, body mass index, fasting plasma glucose, and high-density lipoprotein cholesterol except triglycerides (P = .006). The auROCs for sUA and the sUA-based score were 0.627 (0.607, 0.647) and 0.760 (0.742, 0.777), respectively. A nomogram comprising independent risk factors was developed to predict the 5-year risk of hypertension for each subject.High sUA was significantly associated with the incidence of hypertension in non-MetS subjects adjusting for confounders.

Minocycline inhibits 5-lipoxygenase expression and accelerates functional recovery in chronic phase of focal cerebral ischemia in rats.

AIMS: We previously reported that minocycline attenuates acute brain injury and inflammation after focal cerebral ischemia, and this is partly mediated by inhibition of 5-lipoxygenase (5-LOX) expression. Here, we determined the protective effect of minocycline on chronic ischemic brain injury and its relation with the inhibition of 5-LOX expression after focal cerebral ischemia. MAIN METHODS: Focal cerebral ischemia was induced by 90 min of middle cerebral artery occlusion followed by reperfusion for 36 days. Minocycline (45 mg/kg) was administered intraperitoneally 2h and 12h after ischemia and then every 12h for 5 days. Sensorimotor function was evaluated 1-28 days after ischemia and cognitive function was determined 30-35 days after ischemia. Thereafter, infarct volume, neuron density, astrogliosis, and 5-LOX expression in the brain were determined. KEY FINDINGS: Minocycline accelerated the recovery of sensorimotor and cognitive functions, attenuated the loss of neuron density, and inhibited astrogliosis in the boundary zone around the ischemic core, but did not affect infarct volume. Minocycline significantly inhibited the increased 5-LOX expression in the proliferated astrocytes in the boundary zone, and in the macrophages/microglia in the ischemic core. SIGNIFICANCE: Minocycline accelerates functional recovery in the chronic phase of focal cerebral ischemia, which may be partly associated with the reduction of 5-LOX expression.