Abstract
BACKGROUND: Small-interfering RNA (siRNA) targeting hepatic AGT (angiotensinogen) mRNA depletes AGT, lowering blood pressure for up to 6 months. However, certain situations may require a rapid angiotensin increase. The REVERSIR (RVR) - reverse siRNA silencing technology a potential approach to counteract siRNA effects. METHODS: Spontaneously hypertensive rats received 10 mg/kg AGT siRNA, and 3 weeks later were given AGT-RVR (1, 10, or 20 mg/kg). One week after AGT-RVR dosing, a redose of AGT siRNA assessed its post-AGT-RVR effectiveness for 2 weeks. Additionally, the impact of AGT-RVR after an equihypotensive dose of valsartan (4 mg/kg per day) was examined. RESULTS: Baseline mean arterial pressure (MAP) was 144±1 mm Hg. AGT siRNA reduced MAP by ≈16 mm Hg and AGT by >95%, while renin increased 25-fold. All AGT-RVR doses restored MAP to baseline within 4 to 7 days. Notably, 10 and 20 mg/kg restored AGT and renin to baseline, while 1 mg/kg allowed ≈50% AGT restoration, with renin remaining above baseline. A second AGT siRNA treatment, following 1 mg/kg AGT-RVR, reduced MAP to the same degree as the initial dose, while following 10 mg/kg AGT-RVR, it resulted in ≈50% of the first dose's MAP effect at 2 weeks. The valsartan-induced MAP reduction was unaffected by AGT-RVR. CONCLUSIONS: In spontaneously hypertensive rats, angiotensinogen-RVR dose-dependently reversed AGT siRNA-induced AGT reduction, normalizing MAP. MAP normalization persisted even with 50% recovered AGT levels, likely due to upregulated renin maintaining adequate angiotensin generation. Post-AGT-RVR dosing, a second AGT siRNA dose lowered MAP again.