Abstract P075: Functional NOX2 In T Cells Amplifies Salt-Sensitive Hypertension And Associated Renal Damage

Abstract

Infiltrating T cells in the kidney amplify salt-sensitive (SS) hypertension and renal damage, but the mechanisms are not known. Genetic deletion of T cells (SS CD247-/- ) or the p67phox subunit of NOX2 (SS p67phox-/- ) attenuates salt-sensitive hypertension in the Dahl SS rat. We hypothesized that reactive oxygen species (ROS) produced by NOX2 in T cells drive the SS phenotype and renal damage. T cells were reconstituted by adoptively transferring ~10 million splenocytes from the Dahl SS (SS→CD247, n=14), the SS p67phox-/- (p67phox→CD247, n=19), or PBS only (PBS→CD247, n=8), into the peritoneum of SS CD247-/- rats on postnatal day 5. Animals were instrumented with radiotelemeters at 8 weeks of age. After a week of recovery, blood pressure and albumin excretion were measured while rats were fed a low salt (LS, 0.4% NaCl) diet. Rats were then switched to a high salt (HS, 4.0% NaCl) diet for 21 days, with continuous blood pressure measurements and urine collections every 7 days. On day 22, the rats were euthanized, and their kidneys were perfused and collected for histology and renal immune cell characterization by flow cytometry. At baseline there was no detectable difference in mean arterial pressure (MAP) between groups (124±2 vs 123±2 vs 116±2 mmHg; SS→CD247 vs p67phox→CD247 vs PBS→CD247, respectively). After 21 days of HS, MAP was significantly greater in the SS→CD247 compared to the p67phox→CD247 rats (155±3 vs 144±2 mmHg; p<0.001) and the PBS→CD247 rats (155±3 vs 141±3 mmHg; p<0.001). Indices of renal damage identified no difference in albuminuria between SS→CD247 and p67phox→CD247 on LS (25.8±4.7 vs 23.2±3.2 mg/day). After 21 days of HS, albuminuria was significantly greater in the SS→CD247 (242.8±30.3 mg/day) compared to the p67phox→CD247 (175.5 ± 14.3 mg/day, p<0.03) and PBS→CD247 (135.9±27.8 mg/day, p<0.005). There was no difference between p67phox→CD247 and PBS→CD247 in albuminuria or MAP during LS or HS. The lack of CD3+ cells in the PBS→CD247 but presence of CD3+ cells in rats receiving the T cell transfer demonstrated the effectiveness of the adoptive transfer. These results indicate that ROS production by T cells participates in the amplification of salt-sensitive hypertension and renal damage.