Background/Aims: A major challenge for current therapeutic strategies against ischemia/reperfusion (I/R) is the lack of effective drugs. Considering luteolin enhances the activity of sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2a) to improve the systolic/diastolic function of rat hearts and cardiomyocytes during the I/R process, we studied the regulatory function of the p38 MAPK pathway in this protective mechanism. Methods: Isolated cardiomyocytes and perfused hearts were separately divided into five groups and used to investigate I/R. The phosphorylation of p38 and phospholamban (p-PLB), the levels and activity of SERCA2a and the levels of proteins related to apoptosis were measured. Apoptotic cells were assessed using the TUNEL assay. Single-cell shortening, Ca²⁺ transients, and the decay of the mitochondrial membrane potential (Δψm) were detected. Results: The p38 MAPK pathway was activated during the I/R process, and inhibiting it with SB203580 promoted p-PLB, which enhanced the activity of SERCA2a and relieved the calcium overload to promote the recovery of the Δψm and reduce cardiomyocyte apoptosis in I/R. Luteolin also suppressed the activation of the p38 MAPK pathway and showed cardioprotective effects during I/R injury. Conclusions: We conclude that luteolin enhances SERCA2a activity to improve systolic/diastolic function during I/R in rat hearts and cardiomyocytes by attenuating the inhibitive effects of the p38 pathway on p-PLB.

No abstract

The flavonoid luteolin exists in many types of fruits, vegetables, and medicinal herbs. Our previous studies have demonstrated that luteolin reduced ischemia/reperfusion (I/R) injury in vitro, which was related with sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) activity. However, the effects of luteolin on SERCA2a activity during I/R in vivo remain unclear. To investigate whether luteolin exerts cardioprotective effects and to monitor changes in SERCA2a expression and activity levels in vivo during I/R, we created a myocardial I/R rat model by ligating the coronary artery. We demonstrated that luteolin could reduce the myocardial infarct size, lactate dehydrogenase release, and apoptosis during I/R injury in vivo. Furthermore, we found that luteolin inhibited the I/R-induced decrease in SERCA2a activity in vivo. However, neither I/R nor luteolin altered SERCA2a expression levels in myocardiocytes. Moreover, the PI3K/Akt signaling pathway played a vital role in this mechanism. In conclusion, the present study has confirmed for the first time that luteolin yields cardioprotective effects against I/R injury by inhibiting the I/R-induced decrease in SERCA2a activity partially via the PI3K/Akt signaling pathway in vivo, independent of SERCA2a protein level regulation. SERCA2a activity presents a novel biomarker to assess the progress of I/R injury in experimental research and clinical applications.

Our aim was to examine clinical trials, provide guidance to practitioners and estimate the efficacy and safety of two agents by comparing low dose ticagrelor with standard dose clopidogrel in patients with acute coronary syndrome. We systematically looked through Pubmed, Embase, the Cochrane Library, Wanfang data and CNKI for trials comparing low dose ticagrelor with standard dose clopidogrel for the treatment of patients with ACS since the database was created. The primary endpoint for efficacy was the rate of major adverse cardiac events (MACEs). The primary endpoint for safety was the rate of major bleeding events. We also evaluated platelet function between low dose ticagrelor and standard dose clopidogrel in ACS patients. From 6744 articles, 16 studies including 1629 patients met the inclusion criteria. In contrast with standard dose clopidogrel, low dose ticagrelor significantly reduced MACEs (OR 0.39, 95% CI 0.26, 0.58) and the difference was statistically significant (p<0.01). No difference was noted for major bleeding events (OR 1.16, 95% CI 0.43, 3.08) between the two agents (p=0.77). In addition, low dose ticagrelor showed lower platelet aggregation rate than clopidogrel (standardised mean difference (SMD) −0.68, 95% CI −0.83 to 0.53) (p<0.01). Platelet reaction units for low dose ticagrelor were much lower than those for standard dose clopidogrel (SMD −2.46, 95% CI −2.85 to −2.07) (p<0.01). In comparison with standard dose clopidogrel, low dose ticagrelor significantly lowered the incidence of MACEs, improved left ventricular ejection fraction, decreased left ventricular end diastolic dimension and did not expand the risk of major bleeding events or minor or minimal bleeding events in ACS patients with a considerable safety and efficacy profile. In addition, low dose ticagrelor was associated with dramatically lower platelet aggregation compared with standard dose clopidogrel.

Objective Our purpose was to explore the relationship between triglyceride glucose (TyG) index and the risk of new-onset hypertension in Chinese individuals aged ≥45 years. Methods From 2011 to 2018, data from the China Health and Retirement Longitudinal Survey (CHARLS) were analyzed. The relationship between TyG index and hypertension was assessed utilizing Cox regression and restricted cubic spline (RCS) plot, and the importance of the TyG index in hypertension development was demonstrated by a random forest machine learning model. Finally, subgroup analysis was conducted to test for potential interactions on hypertension development between the TyG index and subgroups. Results 19.7% of the 4755 individuals who were involved in this survey developed hypertension over an average follow-up period of 5.22 years. Compared with the first quartile of albumin, the multivariate HR (95% CI) for the risk of new-onset hypertension across the TyG index quartiles was 1.09 (0.89, 1.33), 1.09 (0.89, 1.33), and 1.29 (1.06, 1.58), respectively ( P for trend <0.001). The RCS plot revealed a linear relationship ( P for nonlinear = 0.322), and the random forest machine learning model illustrated that the TyG index was a significant hazard factor on hypertension development. There was no interaction between subgroups and the relationships of the TyG index with the prevalence of hypertension (all P -value >0.05). Conclusion TyG index was an independent hazard indicator for new-onset hypertension, and routine measurement and control of TyG index level might be great for preventing hypertension development.