Effects of defibrotide on renal function and urinary prostanoid excretion in ciclosporin-treated rats

Effects of nitric oxide blockade and cyclosporin A on cardiovascular and renal function in normal man

OBJECTIVE

The present study investigated whether the nitric oxide (NO) system is involved in cyclosporin A (CsA)-induced changes in cardiovascular and renal function in man.

SUBJECTS AND METHODS

Ten healthy volunteers were investigated twice--with and without intake of a single dose of CsA (8 mg/kg). N(G)-monomethyl-L-arginine (L-NMMA; 3 mg/kg) was injected 4 h after study start on each day.

RESULTS

There was no change in glomerular filtration rate (GFR) on the day without CsA. CsA alone did not change GFR, but after L-NMMA injection, GFR decreased significantly from 101 +/- 4 to 91 +/- 4 ml/min. L-NMMA increased renal vascular resistance with no difference between the two study days. CsA increased significantly the diastolic blood pressure (BP) by 8 +/- 2% and the heart rate (HR) by 30 +/- 4%, without changes in cardiac output L-NMMA further increased BP by around 8%, and decreased HR by 11% and cardiac output by 20% on both study days. L-NMMA decreased urinary flow rate by around 25% and renal sodium clearance from 1.1 to approximately 0.6 ml/min on both study days. CsA decreased plasma renin significantly and increased the urinary excretion rate of prostaglandin E2 (PgE2), 6-keto-prostaglandin F1alpha (6-keto-PgF1alpha) and thromboxane B2(TxB2) when compared to the control day. The urinary excretion rate of NOx and cGMP declined gradually on the control day. In contrast, there was a minor, non-significant increase in NOx and cGMP excretion after CsA, followed by a decrease (29 +/- 2 and 16 +/- 4%, respectively) after L-NMMA in parallel with the decrease in GFR.

CONCLUSION

The present findings suggest that NO does not play a major role during acute CsA-induced changes in cardiovascular function and renal haemodynamics in man. Renal NO synthesis, however, may attenuate the acute CsA-induced decrease in GFR.

Functional and morphological effects of defibrotide on renal ischemia

Defibrotide (Df) has been reported to protect various organs from ischemic damage. The aim of this study was to evaluate the effect of Df on renal function and morphology after warm kidney ischemia. Divided into two groups, 14 pigs underwent bilateral renal clamping for 90 min. One group (7 pigs) was treated with Df (32 mg/kg per h) for 6 h, whereas the control group received 5000 IU of heparin. Serum levels of blood urea nitrogen (BUN) and creatinine measured for 6 days were significantly higher in the control group (peak 26.8 +/- 16.7 vs 11.0 +/- 2.9 mmol/l and 501.2 +/- 351.4 vs 230.2 +/- 68.0 mumol/l P < 0.05). Renal biopsy evidenced a lesser extent of tubular and endothelial damage in Df-treated animals. In conclusion, Df provided relevant protection against renal ischemic injury.