- Email: [email protected]
Alanylglutamine-enriched total parenteral nutrition prevents bacterial translocation after small bowel transplantation in pigs
Alanylglutamine-Enriched Total Parenteral Nutrition Prevents Bacterial Translocation After Small Bowel Transplantation in Pigs H. Yuzawa, T. Azuma, R. Tsutsumi, H. Fujioka, J. Furui, and T. Kanematsu
P
ERIOPERATIVE STRESS, including ischemia/reperfusion injury and total parenteral nutrition (TPN), lead to gut mucosal atrophy and bacterial translocation after small bowel transplantation (SBT). Glutamine has beneficial effects on the maintenance of gut mucosal structure and function during injury.1 Because glutamine is unstable in aqueous solutions, it is not included in commercial amino acids.2 Supplementation of alanylglutamine (Ala-Gln), a soluble and stable form in solutions, may provide beneficial effects on the graft mucosa after SBT. For clinical application of Ala-Gln, we investigated its efficacy using swine SBT models. MATERIALS AND METHODS Heterotopic small bowel autotransplantation was performed using female pigs weighing 20 to 25 kg. The distal small bowel, approximately 200 cm was resected with the superior mesenteric vessels for the graft. The graft was temporarily placed in a basin containing lactated Ringer solution at 4°C (90 ⫾ 30 minutes). The superior mesenteric vein of the graft was anastomosed end-to-side to the vena cava and the superior mesenteric artery was anastomosed end-to-side to the aorta. The graft bowel was anastomosed end-toend to the proximal jejunum and to the terminal ileum. The pigs were divided into two groups according to the postoperative nutritional regimen. Group I (n ⫽ 4) received conventional TPN (glucose 8.8 g/kg per day, amino acids 1.5 g/kg per day). Group II (n ⫽ 3) received Ala-Gln supplementation (1 g/kg per day) TPN. Albumin and BCAA/AAA ratio in serum, and 3-methylhistidine in urine were examined as the nutritional parameters at postoperative days (PODs) 1, 3, 5, and 7. The mucosal thickness of the graft was taken at POD 7, and examined by light microscopy. The numbers of bacteria in mesenteric nodes, liver, and spleen after cultivation were investigated at POD 7.
RESULTS
There were no significant differences in serum levels of albumin and BCAA/AAA ratio between groups I and II. Urinary 3-methylhistidine levels in group I were 7.5 and 8.5 nmol/mL at PODs 5 and 7, whereas those of group II were 4.2 and 4.8 nmol/mL, respectively. There were significant differences in urinary 3-methylhistidine levels between groups I and II (P ⬍ .05) at PODs 5 and 7. The mucosal thickness of the graft was 61.7 ⫾ 2.89 m in controls, 36 ⫾ 4.18 m in group I, and 55 ⫾ 7.07 m in group II. The mucosal thickness of group I was significantly reduced compared with controls (P ⬍ 0041-1345/00/$–see front matter PII S0041-1345(00)01430-5 1662
.005), whereas that of group II was no less than the value of controls. In group I, numbers of bacteria were 7.4 ⫻ 106, 1.1 ⫻ 108, and 1.5 ⫻ 108 in the mesenteric nodes, liver, and spleen, respectively. Those in group II were 5.2 ⫻ 105, 6.7 ⫻ 104, and 4.5 ⫻ 103 in each specimens. DISCUSSION
Serum levels of albumin and BCAA/AAA ratio are appropriate parameters of nutrition and liver function. Increased levels of urinary 3-methylhistidine indicate destruction of skeletal muscle protein under various catabolic conditions. The results from this study demonstrate that Ala-Gln supplementation after SBT reduces destruction of skeletal muscle protein. These findings suggest that Ala-Gln is an important element for maintaining metabolism of amino acids after SBT. Grimble reported that parenteral glutamine supplementation increases mucosal DNA.3 Furthermore, Zhang et al4 reported that Gln-enriched TPN helps to maintain the integrity of the intestinal barrier to lumenal bacteria and to reduce bacterial translocation in SBT in the rat. In our pig model, mucosal atrophy of the graft was severe when conventional TPN was used, whereas mucosal atrophy was prevented with supplementation of Ala-Gln. Also, Ala-Gln reduced the numbers of bacteria in mesenteric nodes, liver, and spleen after SBT. In conclusion, Ala-Gln improves nutritional status and has the potential to help maintain the integrity of graft mucosa, leading to prevention of bacterial translocation through the portal vein during the early stages after SBT in pigs. REFERENCES 1. Schppach W, Loges C, Bartram P, et al: Gastroenterology 107:429, 1994 2. Hammarqvist F, Wernerman J, Decken AVD, et al: Ann Surg 212:637, 1990 3. Grimble GK: Gut 35(Suppl 1):S46, 1994 4. Zang W, Frankel WL, Singh A, et al: Transplantation 56:512, 1993 From the Department of Surgery II, Nagasaki University School of Medicine, Nagasaki, Japan. Address reprint requests to Dr Hiroyuki Yuzawa, Department of Surgery II, Nagsaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan. © 2000 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 Transplantation Proceedings, 32, 1662 (2000)
P
ERIOPERATIVE STRESS, including ischemia/reperfusion injury and total parenteral nutrition (TPN), lead to gut mucosal atrophy and bacterial translocation after small bowel transplantation (SBT). Glutamine has beneficial effects on the maintenance of gut mucosal structure and function during injury.1 Because glutamine is unstable in aqueous solutions, it is not included in commercial amino acids.2 Supplementation of alanylglutamine (Ala-Gln), a soluble and stable form in solutions, may provide beneficial effects on the graft mucosa after SBT. For clinical application of Ala-Gln, we investigated its efficacy using swine SBT models. MATERIALS AND METHODS Heterotopic small bowel autotransplantation was performed using female pigs weighing 20 to 25 kg. The distal small bowel, approximately 200 cm was resected with the superior mesenteric vessels for the graft. The graft was temporarily placed in a basin containing lactated Ringer solution at 4°C (90 ⫾ 30 minutes). The superior mesenteric vein of the graft was anastomosed end-to-side to the vena cava and the superior mesenteric artery was anastomosed end-to-side to the aorta. The graft bowel was anastomosed end-toend to the proximal jejunum and to the terminal ileum. The pigs were divided into two groups according to the postoperative nutritional regimen. Group I (n ⫽ 4) received conventional TPN (glucose 8.8 g/kg per day, amino acids 1.5 g/kg per day). Group II (n ⫽ 3) received Ala-Gln supplementation (1 g/kg per day) TPN. Albumin and BCAA/AAA ratio in serum, and 3-methylhistidine in urine were examined as the nutritional parameters at postoperative days (PODs) 1, 3, 5, and 7. The mucosal thickness of the graft was taken at POD 7, and examined by light microscopy. The numbers of bacteria in mesenteric nodes, liver, and spleen after cultivation were investigated at POD 7.
RESULTS
There were no significant differences in serum levels of albumin and BCAA/AAA ratio between groups I and II. Urinary 3-methylhistidine levels in group I were 7.5 and 8.5 nmol/mL at PODs 5 and 7, whereas those of group II were 4.2 and 4.8 nmol/mL, respectively. There were significant differences in urinary 3-methylhistidine levels between groups I and II (P ⬍ .05) at PODs 5 and 7. The mucosal thickness of the graft was 61.7 ⫾ 2.89 m in controls, 36 ⫾ 4.18 m in group I, and 55 ⫾ 7.07 m in group II. The mucosal thickness of group I was significantly reduced compared with controls (P ⬍ 0041-1345/00/$–see front matter PII S0041-1345(00)01430-5 1662
.005), whereas that of group II was no less than the value of controls. In group I, numbers of bacteria were 7.4 ⫻ 106, 1.1 ⫻ 108, and 1.5 ⫻ 108 in the mesenteric nodes, liver, and spleen, respectively. Those in group II were 5.2 ⫻ 105, 6.7 ⫻ 104, and 4.5 ⫻ 103 in each specimens. DISCUSSION
Serum levels of albumin and BCAA/AAA ratio are appropriate parameters of nutrition and liver function. Increased levels of urinary 3-methylhistidine indicate destruction of skeletal muscle protein under various catabolic conditions. The results from this study demonstrate that Ala-Gln supplementation after SBT reduces destruction of skeletal muscle protein. These findings suggest that Ala-Gln is an important element for maintaining metabolism of amino acids after SBT. Grimble reported that parenteral glutamine supplementation increases mucosal DNA.3 Furthermore, Zhang et al4 reported that Gln-enriched TPN helps to maintain the integrity of the intestinal barrier to lumenal bacteria and to reduce bacterial translocation in SBT in the rat. In our pig model, mucosal atrophy of the graft was severe when conventional TPN was used, whereas mucosal atrophy was prevented with supplementation of Ala-Gln. Also, Ala-Gln reduced the numbers of bacteria in mesenteric nodes, liver, and spleen after SBT. In conclusion, Ala-Gln improves nutritional status and has the potential to help maintain the integrity of graft mucosa, leading to prevention of bacterial translocation through the portal vein during the early stages after SBT in pigs. REFERENCES 1. Schppach W, Loges C, Bartram P, et al: Gastroenterology 107:429, 1994 2. Hammarqvist F, Wernerman J, Decken AVD, et al: Ann Surg 212:637, 1990 3. Grimble GK: Gut 35(Suppl 1):S46, 1994 4. Zang W, Frankel WL, Singh A, et al: Transplantation 56:512, 1993 From the Department of Surgery II, Nagasaki University School of Medicine, Nagasaki, Japan. Address reprint requests to Dr Hiroyuki Yuzawa, Department of Surgery II, Nagsaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan. © 2000 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 Transplantation Proceedings, 32, 1662 (2000)