Effects of epinephrine on angiogenesis-related gene expressions in cultured rat cardiomyocytes

Effects of milrinone on inflammatory response-related gene expressions in cultured rat cardiomyocytes

Congestive heart failure (CHF) is defined as a cardiac dysfunction leading to low cardiac output and inadequate tissue perfusion. Intravenous positive inotropes are used to increase myocardial contractility in hospitalized patients with advanced heart failure. Milrinone is a phosphodiesterase Ⅲ inhibitor and used most commonly for inotropic effect. The well-known PROMISE study investigated the effects of milrinone on mortality in patients with severe CHF, and concluded that long-term therapy with milrinone increased morbidity and mortality among patients with advanced CHF. Previous studies have suggested that phosphodiesterase inhibitors can have potential effects on inflammatory pathways. Hence, we hypothesized that milrinone may alter inflammatory gene expressions in cardiomyocytes, thus leading to adverse clinical outcomes. We used rat cardiomyocyte cell line H9C2 and studied the impact of exposing cardiomyocytes to milrinone (10 μmol/L) for 24 hours on inflammatory gene expressions. RNA extracted from cultured cardiomyocytes was used for whole rat genome gene expression assay (41,000 genes). The following changes in inflammatory response-related gene expressions were discovered. Genes with increased expressions included: THBS2 (+9.98), MMP2 (+3.47), DDIT3 (+2.39), and ADORA3 (+3.5). Genes with decreased expressions were: SPP1 (-5.28) and CD14 (-2.05). We found that the above mentioned gene expression changes seem to indicate that milrinone may hinder the inflammatory process which may potentially lead to adverse clinical outcomes. However, further in vivo and clinical investigations will be needed to illustrate the clinical relevance of these gene expression changes induced by milrinone.

Effects of Epinephrine on Inflammation-Related Gene Expressions in Cultured Rat Cardiomyocytes

Epinephrine, a non-specific adrenergic agonist, is one of the most commonly used inotropes perioperatively. Recent studies have shown that inflammatory response in cardiac surgery could result in hypoperfusion, dysrhythmias, myocardial ischemia, and other pathophysiological alterations in the postoperative period. These alterations might be contributing to the adverse clinical outcome. Although epinephrine has been shown to have effects on the immune system, how epinephrine affects inflammatory response is unclear. We hypothesized that epinephrine exposure may alter the inflammatory response which may potentially contribute to the adverse clinical outcomes. We used cultured rat cardiomyocytes (H9C2) with epinephrine exposure in this study. The expression of mRNA for inflammation-related genes was quantitated for the comparison of experimental group (with epinephrine) and control group (without epinephrine). The results demonstrated significant changes of inflammation-related gene expressions in cardiomyocytes after epinephrine administration. The clinical implications of the gene expression changes in cardiomyocytes are unclear.