Abstract
With the aging of the population, a larger number of elderly patients are undergoing more complex surgical procedures. In addition to advanced age, the general decline in metabolic reserve may lead to an increased risk of perioperative complications in these patients. Furthermore, their specialized nutritional needs remain unclear. Arginine, a semiessential amino acid, has been shown to enhance T-cell-mediated immune function both in healthy animals and in humans.1,2 The use of a specialized enteral feeding with supplemental arginine as well as with omega-3 fatty acids and nucleotides significantly reduced complications and hospital stays in a series of patients undergoing upper gastrointestinal tract surgery for cancer.3
To study the effects of supplemental arginine on wound healing in an elderly but otherwise healthy group of patients, 45 patients were randomly assigned to receive 30 g of arginine (as a syrup) per day or no supplemental arginine (control group) for a total of 2 weeks. Immune function was measured by lymphocyte response to well known mitogens such as phytohemagglutinin, concanavalin A, or poke weed. Mixed-lymphocyte culture quantified the response to alloantigens by noting the increase in thymidine uptake in the lymphocytes of the patients when they were exposed to other human lymphocytes. Wound healing was examined both as the deposition of hydroxyproline into a subcutaneously implanted polytetrafluoroethylene catheter and as the creation of a partial-thickness wound on the anterior aspect of the thigh. The wound was then observed and photographed daily until re-epithelialization had taken place.
All patients tolerated arginine supplementation without notable gastrointestinal tract dysfunction. There was a significant increase in serum insulin-like growth factor (IGF-I) levels (203 ± 18 ng/mL vs 140 ng/mL; p < .04). This is consistent with the role of arginine as a potent pituitary secretogogue. Arginine supplementation further increased collagen deposition into subcutaneous catheters as reflected by increased levels of hydroxyproline (17.4 ± 2 nmol/cm; p < .02). Despite this, there was no increase in the rate of epithelialization of the skin defect (12.5 days). The blastogenic effects of mitogens were significantly increased in all groups from day 1 through day 14. The increases in thymidine incorporation ranged from 15% to 80% for mitogens, with a 300% increase in the mixed-lymphocyte response.
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