Septic cardiomyopathy: A narrative review

PPARA ameliorates sepsis-induced myocardial injury via promoting macrophage M2 polarization by interacting with DUSP1

Background

The morbidity and mortality of sepsis are increasing year by year. Statistically, 40-50% of patients with sepsis have concomitant myocardial injury, and its mortality rate is higher than that of patients with sepsis only. Therefore, it is of great significance to elucidate the mechanism of sepsis-induced myocardial injury.

Methods and results

Human monocytes (THP-1) were used to induce M0 macrophages, followed by treated with lipopolysaccharide (LPS). Cardiomyocytes (AC16) were co-cultured with the conditioned medium of LPS-induced macrophages to induce injury. Quantitative real-time PCR was employed to detect the mRNA levels of peroxisome proliferator-activated receptor α (PPARA) and dual specificity phosphatase 1 (DUSP1). Protein levels of PPARA, macrophage polarization-related markers, apoptosis-related markers, mitochondria-related proteins, and DUSP1 were analyzed by Western blot. Flow cytometry was used to assess M1/M2 cell rates and apoptosis. Low PPARA expression could serve as a biomarker for patients with sepsis. PPARA overexpression enhanced M2 polarization and suppressed M1 polarization in LPS-induced macrophages, and it could alleviate cardiomyocyte injury in co-cultured system. PPARA bound to the DUSP1 promoter region and facilitated its expression. DUSP1 knockdown reversed the effect of PPARA overexpression on M2 polarization and cardiomyocyte injury.

Conclusion

PPARA attenuated cardiomyocyte injury by promoting macrophage M2 polarization through increasing DUSP1 expression, suggesting that PPARA might be a therapy target for sepsis-induced myocardial injury.

Docosahexaenoic acid alleviates LPS-induced cytotoxicity in HL-1 cardiac cells via improving stress-induced mitochondrial fragmentation

Sepsis-induced cardiac injury is associated with oxidative stress and mitochondrial dysfunction. Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects the injured myocardium by modulating mitochondrial dysfunction. We aimed to confirm whether the cardioprotective effect of DHA is mediated via the alleviation of mitochondrial fragmentation in lipopolysaccharide (LPS)-induced cardiomyopathy in vitro. We found that DHA improved cell viability and alleviated cardiac cell apoptosis by reducing lactate dehydrogenase (LDH) release, expression levels of Cleaved caspase-3, and Caspase 3 activity. DHA attenuated oxidative stress as evidenced by decreased ROS production and increased superoxide dismutase activity. In addition, DHA ameliorated mitochondrial dysfunction by modulating mitochondrial respiratory chain injury and mitochondrial fragmentation, especially decreasing the mitochondrial fission-related protein p-Drp1(ser 616) but no effects on Drp1, p-Drp1(ser 637), and mitochondrial fusion-related protein. Our data suggest that DHA conferred cardioprotection by alleviating oxidative stress-induced apoptosis, which may be associated with alleviation of stress-induced mitochondrial fragmentation.

Research Progress on the Mechanism and Management of Septic Cardiomyopathy: A Comprehensive Review

Sepsis is defined as a kind of life-threatening organ dysfunction due to a dysregulated host immune response to infection and is a leading cause of mortality in the intensive care unit. Sepsis-induced myocardial dysfunction, also called septic cardiomyopathy, is a common and serious complication in patients with sepsis, which may indicate a bad prognosis. Although efforts have been made to uncover the pathophysiology of septic cardiomyopathy, a number of uncertainties remain. This article sought to review available literature to summarize the existing knowledge on current diagnostic tools and biomarkers, pathogenesis, and treatments for septic cardiomyopathy.