Glucose-6-phosphate dehydrogenase: a novel therapeutic target in cardiovascular diseases.

Vascular dysfunction associated with diabetes, heart failure and pulmonary hypertension is the major cause of morbidity and mortality worldwide. Although the causes of vascular dysfunction remain unclear, altered glucose metabolism appears to be a common factor in these diseases. For example, in diabetes, increased glucose-6-phosphate dehydrogenase (G6PD) activity and elevated NADPH levels are associated with endothelial and vascular dysfunction. Also, there is a 10-fold increase in myocardial G6PD expression and a 2-fold increase in G6PD activity in pacing-induced heart failure compared with normal hearts. In addition, the inhibition of G6PD ameliorates chronic hypoxic pulmonary hypertension. Lastly, G6PD plays a role in mediating angiotensin II-induced hypertrophy of smooth muscle and in the development of atherosclerosis. While it is understood that G6PD-derived NADPH, which is a cofactor for NADPH oxidase, enhances superoxide anion generation and elevates oxidative stress in diabetes, heart failure, and angiotensin II-induced hypertrophy of smooth muscle, there are no specific drugs available to study the role of G6PD and G6PD-derived NADPH in organ function and the development of human diseases. This warrants the development of new drugs or genetic approaches to target G6PD for investigational and clinical use. This review discusses the specificity and side effects of existing investigational G6PD inhibitors.