Melatonin is a pleiotropic, indole secreted, and synthesized by the human pineal gland. Melatonin has biological effects including anti-apoptosis, protecting mitochondria, anti-oxidation, anti-inflammation, and stimulating target cells to secrete cytokines. Its protective effect on cardiomyocytes in acute myocardial infarction (AMI) has caused widespread interest in the actions of this molecule. The effects of melatonin against oxidative stress, promoting autophagic repair of cells, regulating immune and inflammatory responses, enhancing mitochondrial function, and relieving endoplasmic reticulum stress, play crucial roles in protecting cardiomyocytes from infarction. Mitochondrial apoptosis and dysfunction are common occurrence in cardiomyocyte injury after myocardial infarction. This review focuses on the targets of melatonin in protecting cardiomyocytes in AMI, the main molecular signaling pathways that melatonin influences in its endogenous protective role in myocardial infarction, and the developmental prospect of melatonin in myocardial infarction treatment.

Background With the advancement of the world population aging, more attention should be paid to the prognosis of elderly patients with acute coronary syndrome (ACS). Triglyceride-glucose (TyG) index is a reliable indicator of insulin resistance (IR) and is closely related to traditional risk factors of cardiovascular disease (CVD). However, the effect of TyG index on the prognosis of long-term adverse events in elderly ACS patients has not been reported. This study evaluated the prognostic power of TyG index in predicting adverse events in elderly ACS patients. Methods In this study, 662 ACS patients > 80 years old who were hospitalized from January 2006 to December 2012 were enrolled consecutively and the general clinical data and baseline blood biochemical indicators were collected. The follow-up time after discharge was 40–120 months (median, 63 months; interquartile range, 51‒74 months). In addition, the following formula was used to calculate the TyG index: Ln [fasting TG (mg/dL) × FBG (mg/dL)/2], and patients were divided into three groups according to the tertile of the TyG index. Results The mean age of the subjects was 81.87 ± 2.14 years, the proportion of females was 28.10%, and the mean TyG index was 8.76 ± 0.72. The TyG index was closely associated with the traditional risk factors of CVD. In the fully-adjusted Cox regression model, the Hazard ratio (95% CI) of all-cause mortality (in tertile 3) was 1.64 (1.06, 2.54) and major adverse cardiac event (MACE) (in tertile 3) was 1.36 (1.05, 1.95) for each SD increase in the TyG index. The subgroup analyses also confirmed the significant association of the TyG index and long-term prognosis. Conclusion The TyG index is an independent predictor of long-term all-cause mortality and MACE in elderly ACS patients.

Objective: This study evaluated the prognostic power of serum uric acid (UA) in predicting adverse events in elderly acute coronary syndrome (ACS) patients with diabetes mellitus (DM). Methods: The analysis involved 718 ACS patients >80 years old whose general clinical data and baseline blood biochemical indicators were collected prospectively from January 2006 to December 2012. These patients were classified into two groups based on DM status, and then followed up after discharge. The Kaplan-Meier method was used for major adverse cardiac event (MACE) rates and all-cause mortality. Multivariate Cox regression was performed to analyze the relationship between UA level and long-term clinical prognosis. Receiver operating characteristic (ROC) curves were analyzed to predict the cutoff value of UA in elderly ACS patients with DM. There were 242 and 476 patients in the DM and non-DM (NDM) groups, respectively, and the follow-up time after discharge was 40-120 months (median, 63 months; interquartile range, 51-74 months). Results: The all-cause mortality, cardiac mortality, and MACE rates in both DM and NDM patients were higher than those in the control group (P=0.001). All-cause mortalities, cardiac mortalities, and MACE rates in DM patients with moderate and high UA levels were significantly higher than those in the NDM group (P=0.001). Long-term survival rates decreased significantly with increased UA levels in the ACS groups (P=0.001). UA (odds ratio (OR)=2.106, 95% confidence interval (CI)=1.244-3.568, P=0.006) was found to be an independent risk factor for all-cause mortality and MACE in elderly ACS patients with DM. The cutoff value of UA was 353.6 μmol/L (sensitivity, 67.4%; specificity, 65.7%). Conclusions: Serum UA level is a strong independent predictor of long-term all-cause death and MACE in elderly ACS patients with DM.

Background This study sought to evaluate the prognostic power of serum uric acid (UA) in predicting adverse events of very old acute coronary syndrome (ACS) patients with diabetes mellitus (DM).Methods This analysis involved 718 ACS patients > 80 years old who were collected general clinical data and baseline blood biochemical indicators prospectively from January 2006 to December 2012, and these patients were classified into two groups based on DM, then followed up after discharge. Kaplan–Meier method was performed for major adverse cardiac events (MACE) rates and all-cause mortality. Multivariate Cox regression was performed to analyze the relationship between UA level and long-term clinical prognosis. Receiver operating characteristic (ROC) curve was analyzed to predict the cutoff value of UA of the very old ACS patients with DM.Results There were 242 and 476 patients in groups DM and non-DM(NDM) and the follow-up time after discharge was 40–120 months (median: 63 months; interquartile range: 51–74 months). The differences in all-cause mortality, cardiac mortality and MACE rates in DM and NDM patients between the control group were statistically significant (P = 0.001). All-cause mortality, cardiac mortality and MACE incidence in DM patients with moderate and high UA level were significantly higher than those in control group (P = 0.001). There were statistically significant differences in long-term survival rates among the ACS groups (P = 0.001), and long-term survival rates decreased significantly with the increase of UA level. UA (OR = 2.106, 95%CI = 1.244–3.568, P = 0.006) was found to be an independent risk factor for all-cause mortality and MACE in very old ACS patients with DM. The cutoff value of UA was 353.6 µmol/L (sensitivity: 67.4%; specificity: 65.7%). The elevation of serum UA level play an important role in predicting the development of all-cause mortality in elderly ACS patients with DM.Conclusion Serum UA level is a strong independent predictor of long-term all-cause death and MACE in very old ACS patients with DM.

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