Amino acids and wound healing in people with limb-threatening diabetic foot ulcers

Amino acids are associated with wound healing in traumatic wounds and burns, although their effects on healing in patients with diabetic foot ulcers (DFUs) are limited. This study aimed to evaluate and identify specific amino acids associated with healing outcomes of patients with DFUs. Sixty-two out of 85 patients who completed the in-hospital treatment for limb-threatening DFUs were enrolled. All ulcers had epithelialization without clinical evidence of infection at discharge. The patients and their families were instructed on foot-care techniques and committed to regular follow-up for 1 year. Baseline characteristics, PEDIS wound classification, laboratory data and serum amino acid levels were used to analyze their predictive power. Fifty-seven patients completed the study in which 38 had healed and 19 had unhealed ulcers. The unhealed group had higher incidence of coronary artery disease and larger wound size. Most patients received endovascular therapy (81.6% healed group; 78.9% unhealed group) before enrollment. Following adjustments for clinical factors, the serum levels of arginine (326.4 μmol/L vs. 245.0 μmol/L, P = 0.045), isoleucine (166.7 μmol/L vs. 130.1 μmol/L, P = 0.019), leucine (325.8 μmol/L vs. 248.9 μmol/L, P = 0.039), and threonine (186.7 μmol/L vs. 152.0 μmol/L, P = 0.019) were significantly higher in the healed group. The amino acids associated with wound healing in DFUs differ from those reported for traditional traumatic wounds. These findings affirm the necessity for future large-scaled studies for the application of these amino acids in DFU healing, either as prognostic predictors or supplemented regimens.