Targeted Amino Acid Supplementation in Diabetic Foot Wounds: Pilot Data and a Review of the Literature

Background: Diabetic foot wounds are a highly morbid and costly complication of diabetes mellitus. Targeted amino acid supplementation, by increasing tissue hydroxyproline concentrations, has been implicated in improved wound outcomes in surgical incisions and chronic wounds, and after radiation injury. A major component of collagen, hydroxyproline is a surrogate marker used commonly for tissue collagen concentrations. This paper reviews the literature pertaining to amino acid supplementation and wound healing, and also evaluates our pilot data relating to supplementation with arginine, glutamine, and beta-hydroxy-beta-methylbutyrate (HMB) in the treatment of diabetic foot ulcers. Methods: For the pilot study, nine patients scheduled to undergo wound debridement for diabetic foot ulcers were randomized prospectively to be a part of either a placebo group or a treatment group that received supplementation twice daily for 2 wks. Tissue samples were collected both before and after 2 wk of supplementation. The results of assay of the samples for hydroyproline were then analyzed via a one tailed Student t -test to evaluate tissue concentrations of hydroxyproline. For the literature review in the study, the MEDLINE/PubMed database was reviewed, using search terms contained in the Medical Subject Headings (MeSH). Results: The treatment group in the study exhibited a significantly greater hydroxyproline concentration after supplementation than before it (p=0.03). The mean percent change in the tissue hydroxyproline concentration for arginine, glutamine, and HMB group was +67.8%, with a standard deviation (SD) of 129.89. The mean percent change for the corresponding amino acids in the placebo group was −78.4%, with an SD of 20.55. The review of the MEDLINE/PubMed literature revealed only two human studies of amino acid supplementation in patients with diabetic foot wounds, one of which found a significant improvement in wound-depth and wound-appearance scores. Conclusions: Given the results of our pilot study, and on the basis of a review of the literature, the administration of a simple amino acid supplement may improve the healing of diabetic foot wounds via increased collagen production.