ABSTRACT The effect of glutamine dipeptide (GDP) supplementation in patients with diabetic foot syndrome was evaluated. A total of 22 patients took part in the study. GDP was supplied in 10 g sachets, and was dissolved in water immediately before use, with ingestion once a day, after lunch or after dinner (20 g/day) over a period of 30 days. Quantification of foot insensitive areas, oxidative stress, blood cytokines, and biochemical, hematological and toxicological parameters was performed before and after GDP supplementation. We observed an increase in blood levels of interferon-α (P=0.023), interferon-γ (P=0.038), interleukin-4 (P=0.003), interleukin-6 (P=0.0025), interleukin-7 (P=0.028), interleukin-12 p40 (P=0.017), interleukin-13 (P=0.001), leukocytes (P=0.037), eosinophils (P=0.049), and typical lymphocytes (P<0.001) due to GDP administration. In addition, we observed a reduced number (P=0.048) of insensitive areas on the foot, and reduction (P=0.047) of fasting hyperglycemia. Patients also showed increased blood high density lipoprotein (P<0.01) and protein thiol groups (P=0.004). These favorable results were associated with the absence of renal and hepatic toxicity. These results are of clinical relevance, since supplementation with GDP over 30 days improved clinical responses in patients with diabetic foot syndrome.

The aim of this study was to determine whether plasma levels of carbonylated proteins, total antioxidant capacity (TAC) and reduced protein thiols could be suitable biomarkers of risk factors for diabetic foot. Individuals with type 2 diabetes with normal protective sensation (normal foot group) vs. loss of protective sensation and/or signs of peripheral arterial disease and/or foot deformities and/or history of ulcers and/or neuropathic fractures and/or amputation (diabetic foot group) were compared. The diabetic foot group showed higher carbonylated protein levels (P = 0.0457) and lower levels of TAC (P = 0.0148) and reduced protein thiols (P = 0.0088), compared with the normal foot group. In general, several other parameters of risk of diabetes complication (blood levels of glycated hemoglobin, glucose and cholesterol, duration of diabetes, body mass index and waist circumference) showed a tendency of higher values in the diabetic foot group. The results suggest that the plasma levels of carbonylated proteins, TAC and reduced protein thiols could furnish information about the risk of diabetic foot, considering that the changes in these biomarkers were associated with the loss of sensitivity and foot ulcerations.