BACKGROUND: We previously found that higher NADPH levels produced by glucose-6-phosphate dehydrogenase (G6PD) can enhance myocardial superoxide generation by NAD(P)H oxidase in a dog model of dilated cardiomyopathy. Therefore, we tested whether G6PD activity is elevated and enhances NADPH level and increases NAD(P)H oxidase-derived superoxide production in the myocardium from patients with heart failure from ischemic cardiomyopathy. METHODS AND RESULTS: Surgical discards of left ventricle were collected from 8 congestive heart failure patients undergoing surgical ventricular restoration procedures, whereas control left ventricle tissue was obtained from 5 normal donor hearts deemed not suitable for transplantation. Biochemical assays were performed in tissue homogenates. We found that superoxide and hydrogen peroxide were elevated, respectively, by 9- and 3-fold in failing versus normal hearts (P < .05). The NAD(P)H oxidase inhibitors gp91(ds-tat), apocynin, and diphenyleneiodonium, significantly inhibited superoxide generation by approximately 75%, 89%, and 91%, respectively. Superoxide production by NAD(P)H oxidase increased 10- and 3-fold by adding NADPH (100 micromol/L) and NADH (100 micromol/L), respectively, in a DPI- and gp91(ds-tat)-inhibitable manner. Interestingly, chelerythrine, a PKC inhibitor, and PP2, a Src kinase family inhibitor, reduced G6PD activity (0.29 +/- 0.04 nM x min x mg protein) by 50% and 51% and these inhibitors also decreased myocardial superoxide by 99% and 79%, respectively. Furthermore, 6-aminonicotinamide, a G6PD inhibitor, decreased myocardial superoxide production by 71%. CONCLUSIONS: These data suggest that high NAD(P)H oxidase, fueled by G6PD-derived NADPH, generates most of the superoxide in failing hearts of patients with ischemic cardiomyopathy. In addition, PKC-Src kinase signaling pathways seem to coordinate the activation of both G6PD and NAD(P)H oxidase in human cardiac muscle.
BACKGROUND: We previously found that higher NADPH levels produced by glucose-6-phosphate dehydrogenase (G6PD) can enhance myocardial superoxide generation by NAD(P)H oxidase in a dog model of dilated cardiomyopathy. Therefore, we tested whether G6PD activity is elevated and enhances NADPH level and increases NAD(P)H oxidase-derived superoxide production in the myocardium from patients with heart failure from ischemic cardiomyopathy. METHODS AND RESULTS: Surgical discards of left ventricle were collected from 8 congestive heart failurepatients undergoing surgical ventricular restoration procedures, whereas control left ventricle tissue was obtained from 5 normal donor hearts deemed not suitable for transplantation. Biochemical assays were performed in tissue homogenates. We found that superoxide and hydrogen peroxide were elevated, respectively, by 9- and 3-fold in failing versus normal hearts (P < .05). The NAD(P)H oxidase inhibitors gp91(ds-tat), apocynin, and diphenyleneiodonium, significantly inhibited superoxide generation by approximately 75%, 89%, and 91%, respectively. Superoxide production by NAD(P)H oxidase increased 10- and 3-fold by adding NADPH (100 micromol/L) and NADH (100 micromol/L), respectively, in a DPI- and gp91(ds-tat)-inhibitable manner. Interestingly, chelerythrine, a PKC inhibitor, and PP2, a Src kinase family inhibitor, reduced G6PD activity (0.29 +/- 0.04 nM x min x mg protein) by 50% and 51% and these inhibitors also decreased myocardial superoxide by 99% and 79%, respectively. Furthermore, 6-aminonicotinamide, a G6PD inhibitor, decreased myocardial superoxide production by 71%. CONCLUSIONS: These data suggest that high NAD(P)H oxidase, fueled by G6PD-derived NADPH, generates most of the superoxide in failing hearts of patients with ischemic cardiomyopathy. In addition, PKC-Src kinase signaling pathways seem to coordinate the activation of both G6PD and NAD(P)H oxidase in human cardiac muscle.
Authors: Peter A Hecker; Tatiana F Galvao; Karen M O'Shea; Bethany H Brown; Reney Henderson; Heather Riggle; Sachin A Gupte; William C Stanley Journal: Nutrition Date: 2012-02-02 Impact factor: 4.008
Authors: Khaled Qanud; Mohammed Mamdani; Martino Pepe; Ramzi J Khairallah; John Gravel; Biao Lei; Sachin A Gupte; Victor G Sharov; Hani N Sabbah; William C Stanley; Fabio A Recchia Journal: Am J Physiol Heart Circ Physiol Date: 2008-09-26 Impact factor: 4.733
Authors: Rakhee S Gupte; Beverly C Floyd; Mark Kozicky; Shimran George; Zoltan I Ungvari; Vanessa Neito; Michael S Wolin; Sachin A Gupte Journal: Free Radic Biol Med Date: 2009-02-20 Impact factor: 7.376
Authors: Peter A Hecker; Jane A Leopold; Sachin A Gupte; Fabio A Recchia; William C Stanley Journal: Am J Physiol Heart Circ Physiol Date: 2012-12-15 Impact factor: 4.733