Comparative study of aminoglycoside nephrotoxicity in normal rats and rats with experimental cirrhosis

Renal effects of gentamicin in chronic bile duct ligated rats

Patients with advanced cirrhosis and rats with short-term bile duct ligation (BDL) are prone to develop nephrotoxicity from aminoglycosides. In this study, we characterized the renal response to gentamicin in rats with chronic BDL. BDL and sham-operated (SO) rats were given gentamicin (20 and 40 mg/kg/d) for 7 consecutive days, starting on the 18th postoperative day. Administration of gentamicin to SO group caused a decrease in cortical and medullary prostaglandin E(2)(PGE(2)) generation. However, mild reduction in creatinine clearance and an increase in fractional excretion of sodium occurred only in the BDL rats given the high gentamicin dose. This was accompanied by a reduction in cortical and medullary PGE(2) generation and a reduction in plasma nitric oxide production. In conclusion, gentamicin administration to rats with chronic BDL causes impairment of renal function. This happens only after the occurrence of simultaneous multiple insults to the renal protective mechanisms.

Risk factors for the development of renal dysfunction in hospitalized patients with cirrhosis

OBJECTIVE

Hospitalized patients with liver cirrhosis are predisposed to acute renal failure. We sought to identify the role of liver disease severity, infectious complications, and in-hospital treatment with aminoglycosides as risk factors for acute renal failure among patients with cirrhosis.

METHODS

In a retrospective, case-control study at the Albuquerque VA Medical Center, electronic and manual chart review was employed to identify all hospitalized patients with a diagnosis of cirrhosis and normal renal function (serum creatinine < or = 1.3 mg/dl) at the time of hospitalization. Cases were defined as patients who developed renal dysfunction (increase in creatinine of > or = 1.0 mg/dl) within 15 days of hospitalization, and the remaining patients were controls.

RESULTS

Of 93 patients, there were 23 cases and 70 controls. There were no significant differences in age, etiology of cirrhosis, serum levels of albumin, or bilirubin, prothrombin time, encephalopathy, bacteremia, urinary tract infection, or occurrence of esophageal variceal bleeding. Patients who developed renal dysfunction were more likely to have ascites (87% vs 41%, p < 0.01), spontaneous bacterial peritonitis (44% vs 1%, p < 0.01), and treatment with i.v. aminoglycosides (48% vs 19%, p < 0.01). In a multivariate logistic regression analysis, aminoglycosides treatment was a strong risk factor for renal dysfunction (adjusted odds ratio = 4.0, 95% CI = 1.4-11), independent of the severity of liver disease or peritonitis.

CONCLUSION

Avoidance of aminoglycoside antibiotics may reduce the occurrence of renal dysfunction in hospitalized patients with cirrhosis. In addition, close monitoring of renal function should be employed among patients with ascites and/or spontaneous bacterial peritonitis.

Gentamicin nephrotoxicity in extrahepatic cholestasis: modulation by dietary calcium

The present study was designed to test the hypothesis that the presence of a specific hepatobiliary disease, namely common bile duct obstruction, in the absence of other risk factors will exacerbate gentamicin nephrotoxicity. Furthermore, since bile duct ligation decreases urinary calcium excretion, we studied the role of calcium supplementation in the prevention of gentamicin nephrotoxicity in this model. Male Sprague-Dawley rats were allocated to sham groups and common bile duct ligation groups. Gentamicin at 40 and 100 mg per kg per day for 5 days induced a more severe azotemia in common bile duct ligation animals than in sham controls. Furthermore, higher levels of renal gentamicin were found in common bile duct ligation rats than in sham rats early in the course of therapy, at its termination and during the recovery period. Pretreatment of common bile duct ligation animals with dietary calcium supplementation significantly attenuated gentamicin nephrotoxicity and the increased renal gentamicin accumulation, whereas initiation of calcium supplementation concurrent with gentamicin administration had no salutary effect. We conclude that experimental extrahepatic cholestasis in the rat, in the absence of any other factor, potentiates gentamicin nephrotoxicity. The effect is prevented by pretreatment with dietary calcium supplementation but is not modified by concurrent administration of a high-calcium diet.