AIM:To investigate the relationship between polyamine metabolism and hypoxia /ischemia ( H/I)-induced cell apoptosis and to determine the mechanisms by which exogenous spermine protects cell apoptosis against AMI in rats .METHOD:The left anterior de-scending coronary artery ( LAD) of the Wistar rats were ligated , and neonatal rat cardiomyocytes were placed under hypoxic conditions for 24 h to establish the model of AMI (or H/I).Exogenous spermine was administered by intraperitoneal injection (2.5 mg/kg daily for 7 days) in vitro and subjected to the cell medium at 5μmol/L as a pre-treatment therapy.RESULTS:AMI (or H/I) induced an increase in polyamine catabolized enzyme SSAT and a decrease in polyamine biosynthesis enzyme ODC , which result in endogenous spermine and spermidine decrease and putrescine increase .At the same time, AMI ( or H/I) lowered cardiac function , increased cTnI and CK-MB concentrations , aggravated myocardial infarct size , cardiomyocyte damage and apoptosis , raised ROS generation , increased the expression of cleaved caspase-3, cleaved caspase-9 and endoplasmic reticulum stress (ERS)-related proteins, promoted the release of cytochrome C and mPTP opening , down-regulated Bcl-2 expression and the phosphorylation of ERK 1/2, PI3K, Akt and GSK-3β, and activated PERK and eIF 2αphosphorylation .Spermine pre-treatment reversed the above-motioned changes .CONCLUSION:AMI ( or H/I ) could induce cardiomyocyte apoptosis and polyamine metabolism disorder .Exogenous spermine attenuates cardiac injury through scavenging the ROS and inhibiting mPTP opening and ERS injury .These findings provide a novel target for the prevention of apoptosis in the setting of AMI .

Objective:To investigate the predictive factors of poor prognosis in children with acute kidney injury (AKI) treated with renal replacement therapy (RRT).Methods:In this retrospective case-control study, the clinical data were collected from 134 pediatric patients (82 male, 52 female) with AKI treated with RRT in six tertiary hospitals from May 2015 to June 2018. According to the serum creatinine level at discharge, the patients were divided into the favorable outcome group and unfavorable outcome group. The data of sex, age, primary diseases, AKI stage, time from diagnosis of AKI to start of RRT (h) and whether to start RRT within 24 hours, urine volume and complications between the two groups were compared. Continuous variables were compared by t test and Mann-Whitney U test, and percentage or proportions were compared by Chi square test. The predictive factors of adverse prognosis were analyzed by using univariate and unconditional binary logistic regression analysis. Results:The average age of the 134 AKI patients was (6±4) years. There were 114 patients (85.0%) in the favorable outcome group and 20 patients (15.0%) in the unfavorable outcome group. No statistically significant differences were found between the two groups in terms of sex (χ 2=2.596, P=0.107), age ( t=0.718, P=0.474), primary disease (χ 2=2.076, P=0.722), AKI stage (χ 2=0.004, P=0.998), time from diagnosis of AKI to start RRT (h) ( P=0.745), whether to start RRT within 24 hours (χ 2=0.016, P=0.899), urine volume (χ 2=3.118, P=0.374), fluid overload (χ 2=0.014, P=0.905), multiple organ dysfunction syndrome (MODS) (χ 2=2.972, P=0.085), acidosis (χ 2=3.204, P=0.073), hyperkalemia (χ 2=2.829, P=0.093), the level of blood urea nitrogen ( t=1.351, P=0.179) and serum creatinine ( P=0.901) at the beginning of RRT. In the unfavorable outcome group, the proportion of patients with mechanical ventilation (45.0% (9/20) vs. 12.3% (14/114), χ 2=12.811, P<0.01) and the incidence of extra organ injury (≥3) (30.0% (6/20) vs. 10.5% (12/114), χ 2=6.365, P=0.041) were higher than those in the favorable outcome group. Logistic regression analysis showed that mechanical ventilation ( OR=12.540, 95 %CI: 3.376-46.577, P<0.01) and hyperkalemia ( OR=4.611, 95 %CI: 1.265-16.805, P=0.021) were the predictive factors of poor prognosis in patients with AKI treated with RRT. Conclusion:Mechanical ventilation and hyperkalemia may predict a poor prognosis in AKI patients treated with RRT.