Potentiation of ischemic renal injury by amino acid infusion

The purpose of this study was to determine whether amino acid hyperalimentation sensitizes the kidney to ischemic renal injury. Sprague-Dawley rats were infused with a control infusate or control infusate plus 15 essential and nonessential amino acids (FreAmine III, 2 mg of amino acids/kg/min). After 1 hr, bilateral renal ischemia was induced (15 min pedicle cross clamp). GFR, urine flow, and renal blood flow (RBF) were measured before and for 0 to 2 hr postischemia. None of these parameters were statistically different between the two groups of rats prior to renal ischemia. However, the decrease in GFR following renal ischemia was twice as great in the amino acid versus the nonamino acid treatment group (↓ 73 ± 4% vs. ↓ 36 ± 4%, respectively; P < 0.001). The postischemia urine flow rate was also significantly less (P < 0.01) with amino acid treatment. RBF did not differ between the two groups. Renal histology confirmed greater tubular injury with amino acid treatment (P < 0.001). In conclusion, infusion of therapeutic doses of amino acids can exacerbate early functional and histologic parameters of ischemic renal injury and thus, may sensitive the kidney to ischemic acute renal failure.