Complementary effects of adenosine and angiotensin II in hypoxemia-induced renal dysfunction in the rabbit.

The acute renal effects of hypoxemia and the ability of the co-administration of an angiotensin converting enzyme inhibitor (perindoprilat) and an adenosine receptor antagonist (theophylline) to prevent these effects were assessed in anesthetized and mechanically-ventilated rabbits. Renal blood flow (RBF) and glomerular filtration rate (GFR) were determined by the clearances of para-aminohippuric acid and inulin, respectively. Each animal acted as its own control. In 8 untreated rabbits, hypoxemia induced a significant drop in mean blood pressure (-12 +/- 2%), GFR (-16 +/- 3%) and RBF (-12 +/- 3%) with a concomitant increase in renal vascular resistance (RVR) (+ 18 +/- 5%), without changes in filtration fraction (FF) (-4 +/- 2%). These results suggest the occurrence of both pre- and postglomerular vasoconstriction during the hypoxemic stress. In 7 rabbits pretreated with intravenous perindoprilat (20 microg/kg), the hypoxemia-induced changes in RBF and RVR were prevented. FF decreased significantly (-18 +/- 2%), while the drop in GFR was partially blunted. These results could be explained by the inhibition of the angiotensin-mediated efferent vasoconstriction by perindoprilat. In 7 additional rabbits, co-administration of perindoprilat and theophylline (1 mg/kg) completely prevented the hypoxemia-induced changes in RBF (+ 11 +/- 3%) and GFR (+ 2 +/- 3%), while RVR decreased significantly (-14 +/- 3%). Since adenosine and angiotensin II were both shown to participate, at least in part, in the renal changes induced by hypoxemia, the beneficial effects of perindoprilat and theophylline in this model could be mediated by complementary actions of angiotensin II and adenosine on the renal vasculature

Long-term effects of in utero exposure to cyclosporin A on renal function in the rabbit.

The number of pregnant women who receive cyclosporin A (CsA) after transplantation or for autoimmune disease has increased. CsA and its metabolites can cross the placental barrier and thus interfere with fetal development. It was shown previously that rabbits that were exposed in utero to 10 mg/kg per d CsA from the 14th to the 18th day of gestation presented a 25% nephron reduction. Thus, this study was conducted to assess the long-term systemic and renal effects of a CsA-induced nephron reduction. Twenty-two pregnant New Zealand white rabbits were randomly divided into two groups: Twelve received 10 mg/kg per d CsA from day 14 to day 18 of gestation, and 10 were used as controls. Rabbits that were born to these animals were evaluated at 4, 11, 18, and 35 wk of life. Pups that were exposed antenatally to CsA presented first a permanent nephron deficit; second, glomerular, tubular, and intrarenal hemodynamics dysfunction; third, enlarged kidneys with numerous tubular and glomerular lesions; and, fourth, an endothelin-dependent systemic hypertension that worsened with age. In utero exposure to CsA induced a nephron reduction that led to systemic hypertension and progressive chronic renal insufficiency in adulthood. A long-term clinical survey is mandatory in infants who are born to mothers who were treated with cyclosporin during pregnancy