Perioperative glutamine supplementation restores disturbed renal arginine synthesis after 1 open aortic surgery : a randomized controlled clinical trial

29 30 Background: Postoperative renal failure is a common complication after open repair of an 31 abdominal aortic aneurysm. The amino acid arginine is formed in the kidneys from its precursor 32 citrulline, and citrulline is formed from glutamine in the intestines. Arginine enhances the 33 function of the immune and cardiovascular system, which is important for recovery after surgery. 34 We hypothesized that renal arginine production is diminished after ischemia-reperfusion injury 35 caused by clamping of the aorta during open abdominal aortic surgery and that parenteral 36 glutamine supplementation might compensate for this impaired arginine synthesis. 37 38 Methods: This open-label clinical trial randomized patients who underwent clamping of the 39 aorta during open abdominal aortic surgery to receive a perioperative supplement of intravenous 40 alanyl-glutamine (0.5 · kg · day; group A, n = 5) or no supplement (group B, n = 5). One day 41 after surgery, stable isotopes and tracer methods were used to analyze the metabolism and 42 conversion of glutamine, citrulline, and arginine. 43 44 Results: Whole-body plasma flux of glutamine, citrulline, and arginine was significantly higher 45 in group A than in group B (glutamine, 391 ± 34 vs 258 ± 19; citrulline, 5.7 ± 0.4 vs 2.8 ± 0.4; 46 and arginine, 50 ± 4 vs 26 ± 2 μmol · kg · h, respectively; p < 0.01), as was synthesis of 47 citrulline from glutamine (4.8 ± 0.7 vs 1.6 ± 0.3 μmol · kg · h), citrulline from arginine (2.3 ± 48 0.3 vs 0.96 ± 0.1 μmol · kg · h), and arginine from glutamine (7.7 ± 0.4 vs 2.8 ± 0.2 μmol · 49 kg · h), respectively (p < 0.001 for all). 50