Prevention of Acute Cyclosporine Nephrotoxicity by Atrial Natriuretic Factor After Ischemia in the Rat

The present experimental study investigates whether the atrial natriuretic factor (ANF) is able to prevent the nephrotoxic effects of cyclosporine infused after 30 min of warm renal ischemia in the rat. At 2 hr after the end of ischemia, the glomerular filtration rate was improved by an ANF infusion: 390 +/- 19 microliters/min/100 g versus 298.3 +/- 31 microliters/min/100 g in ANF and saline-infused rats, respectively (P less than 0.05). Intravenous CsA infusion at a dose of 2.5 mg/kg/day produced a more pronounced fall in GFR when compared with the control: 205.4 +/- 19.7 microliters/min/100 g versus 298.3 +/- 31 microliters/min/100 g in CsA and saline, respectively (P less than 0.05). In contrast, a synthetic rat atriopeptin III (0.5 microgram/kg/min) infusion after ischemia given together with CsA prevented its deleterious effects upon GFR: 316 +/- 22 microliters/min/100 g versus 205.4 +/- 19 microliters/min/100 g in ANF/CsA versus CsA alone (P less than 0.001). Moreover, the natriuretic ANF effects remained unaffected by high plasma CsA peak levels: indeed, other parameters of renal function--urinary flow, urinary sodium concentration and excretion rates, and urinary sodium reabsorption and fractional excretion rates, were significantly increased in ANF alone or CsA/ANF groups. These preliminary results suggest that ANF may be useful in renal transplantation or in the management of patients given large doses of CsA (liver or heart transplant) since, despite nephrotoxic CsA levels (greater than 1500 ng/ml), ANF provides an improved GFR and tubular function after ischemia.