Inflammatory Mediators of Endothelial Dysfunction

Endothelial dysfunction (ED) is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and inflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. It has been reported that the maintenance of endothelial cell integrity serves a significant role in human health and disease due to the involvement of the endothelium in several processes, such as regulation of vascular tone, regulation of hemostasis and thrombosis, cell adhesion, smooth muscle cell proliferation, and vascular inflammation. Inflammatory modulators/biomarkers, such as IL-1α, IL-1β, IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor α, or alternative anti-inflammatory cytokine IL-10, and adhesion molecules (ICAM-1, VCAM-1), involved in atherosclerosis progression have been shown to predict cardiovascular diseases. Furthermore, several signaling pathways, such as NLRP3 inflammasome, that are associated with the inflammatory response and the disrupted H2S bioavailability are postulated to be new indicators for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we summarize the knowledge of a plethora of reviews, research articles, and clinical trials concerning the key inflammatory modulators and signaling pathways in atherosclerosis due to endothelial dysfunction.

Effects of hydrogen sulphide on the isolated perfused rat heart

OBJECTIVES

Hydrogen sulphide has been identified as a gas signalling molecule in the body, and has previously been shown to have vasorelaxant properties. The aim of the study was to investigate the effects of sodium hydrosulphide (NaHS), a hydrogen sulphide donor, on heart rate (HR), left ventricular developed pressure (LVDP) and coronary flow (CF) in the isolated perfused rat heart.

METHODS

A Langendorff isolated heart preparation was used to investigate the effect of a dose range of sodium hydrosulphide, in the presence and absence of inhibitors, on heart rate, left ventricular developed pressure and coronary flow.

RESULTS

Sodium hydrosulphide caused a significant decrease in heart rate at a concentration of 10-3 M (P <0.001). This decrease was partially inhibited by glibenclamide, a K(ATP) channel blocker (P <0.05); L-NAME, a nitric oxide synthase inhibitor (P <0.001), and methylene blue (P <0.001), but not by H-89, a protein kinase A inhibitor. Sodium hydrosulphide significantly increased coronary flow at concentrations of 10-4 - 10-3M (P <0.05). This response was significantly increased in the presence of L-NAME (P <0.001) and methylene blue (P <0.001), whereas H-89 inhibited the increase in coronary flow due to sodium hydrosulphide (P <0.001). Sodium hydrosulphide significantly decreased LVDP at all concentrations (P <0.001). In the presence of glibenclamide and H-89, the time period of the decrease in LVDP due to sodium hydrosulphide was extended (P <0.001), whereas methylene blue and L-NAME caused a significant reduction in the response to sodium hydrosulphide (P <0.05, P <0.01 respectively).

CONCLUSION

Sodium hydrosulphide reduced heart rate and LVDP, and increased coronary flow in the isolated perfused rat heart; however, the mechanisms of action could not be fully elucidated.