Glycine treatment decreases proinflammatory cytokines and increases interferon-γ in patients with Type 2 diabetes


Background: Amino acids have been shown to stimulate insulin secretion and decrease glycated hemoglobin (A1C) in patients with Type 2 diabetes. In vitro, glycine reduces tumor necrosis factor (TNF)-α secretion and increases interleukin-10 secretion in human monocytes stimulated with lipopolysaccharide. The aim of this study was to determine whether glycine modifies the proinflammatory profiles of patients with Type 2 diabetes. Materials/subjects and methods: Seventy-four patients, with Type 2 diabetes were enrolled in the study. The mean age was 58.5 yr, average age of diagnosis was 5 yr, the mean body mass index was 28.5 kg/m2, the mean fasting glucose level was 175.5 mg/dl and the mean A1C level was 8%. They were allocated to one of two treatments, 5 g/d glycine or 5 g/d placebo, po tid, for 3 months. Results: A1 C levels of patients given glycine were significantly lower after 3 months of treatment than those of the placebo group. A significant reduction in TNF-receptor I levels was observed in patients given glycine compared with placebo. There was a decrease of 38% in the interferon (IFN)-γ level of the group treated with placebo, whereas that of the group treated with glycine increased up to 43%. These data showed that patients treated with glycine had a significant decrease in A1C and in proinflammatory cytokines and also an important increase of IFN-γ. Conclusion: Treatment with glycine is likely to have a beneficial effect on innate and adaptive immune responses and may help prevent tissue damage caused by chronic inflammation in patients with Type 2 diabetes.

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Correspondence to M. Cruz PhD.

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These authors contributed equally.

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Cruz, M., Maldonado-Bernal, C., Mondragón-Gonzalez, R. et al. Glycine treatment decreases proinflammatory cytokines and increases interferon-γ in patients with Type 2 diabetes. J Endocrinol Invest 31, 694–699 (2008).

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  • A1C
  • glucose metabolism
  • glycine treatment
  • proinflammatory cytokines
  • Type 2 diabetes