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: