ARGININE STIMULATES WOUND-HEALING AND IMMUNE FUNCTION IN ELDERLY HUMAN-BEINGS

Background Experimentally, arginine enhances immune function and promo tes wound healing. In this randomized double-blind study we investigat ed the effect of oral arginine supplementation on wound healing and T- cell function in elderly human beings (more than 65 years of age). Met hods. Thirty elderly, healthy, human volunteers (15 men and 15 women) received daily supplements of 30 gm arginine aspartate (17 gm free arg inine). Fifteen volunteers (nine men and six women) received a placebo syrup. Fibroplastic wound responses were assessed by inserting a poly tetrafluoroethylene catheter subcutaneously into the right deltoid reg ion. Epithelialization was examined by creating a 2 X 2 cm split thick ness wound on the lateral aspect of the upper thigh. Mitogenic respons e of peripheral blood lymphocytes to concanavalin A, phytohemagglutimi n, pokeweed mitogen, and allogeneic stimuli was assayed at the beginni ng and end of supplementation. Polytetrafluoroethylene catheters were analyzed for alpha-amino nitrogen (assessment of total protein accumul ation), hydroxyproline (index of reparative collagen synthesis), and D NA accumulation (index of cellular infiltration). Results. Arginine su pplementation for 2 weeks significantly enhanced wound catheter hydrox yproline accumulation (26.49 +/- 2.39 nmol/cm vs 17.41 +/- 2.04 nmol/c m) and total protein content (43.47 +/- 3.85 mug/cm vs 21.95 +/- 2.5 m ug/cm). Arginine did not influence the DNA content of the catheters or the rate of epithelialization of the skin defect. Peripheral blood ly mphocyte responses to mitogenic and allogenic stimulation were greater in the arginine supplemented group. Serum insulin-like growth factor- 1 levels were significantly elevated in the arginine group. Conclusion s. The data suggest that arginine supplementation may improve wound he aling and immune responses in the elderly.