Dietary flavonol epicatechin prevents the onset of type 1 diabetes in nonobese diabetic mice.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective destruction of pancreatic ß-cells. Although successful islet transplantation provides a promising treatment, high cost, lack of donor organs, immune-mediated destruction of transplanted islets, and side effects from immunosuppressive drugs greatly limit its uses. Therefore, the search for novel and cost-effective agents that can prevent or ameliorate T1D is extremely important to decrease the burden of T1D. In this study, we discovered that epicatechin (EC, 0.5% in drinking water), a flavonol primarily in cocoa, effectively prevented T1D in nonobese diabetic (NOD) mice. At 32 weeks of age, 66.7% of control mice had overt diabetes, whereas only 16.6% of EC-treated mice became diabetic. Consistently, EC mice had significantly higher plasma insulin levels but lower glycosylated hemoglobin concentrations compared to control mice. EC had no significant effects on food or water intake and body weight gain in NOD mice, suggesting that EC's effect was not due to alterations in these variables. Treatment with EC elevates circulating anti-inflammatory cytokine interleukin-10 levels, ameliorates pancreatic insulitis, and improves pancreatic islet mass. These findings demonstrate that EC may be a novel, plant-derived compound capable of preventing T1D by modulating immune function and thereby preserving islet mass.

Epigallocatechin gallate delays the onset of type 1 diabetes in spontaneous non-obese diabetic mice.

Type 1 diabetes (T1D) results from the autoimmune-mediated destruction of pancreatic ß-cells, leading to deficiency of insulin production. Successful islet transplantation can normalise hyperglycaemia in T1D patients; however, the limited availability of the islets, loss of islet cell mass through apoptosis after islet isolation and potential autoimmune destruction of the transplanted islets prevent the widespread use of this procedure. Therefore, the search for novel and cost-effective agents that can prevent or treat T1D is extremely important to decrease the burden of morbidity from this disease. In the present study, we discovered that ( - )-epigallocatechin gallate (EGCG, 0·05 % in drinking-water), the primary polyphenolic component in green tea, effectively delayed the onset of T1D in non-obese diabetic (NOD) mice. At 32 weeks of age, eight (66·7 %) out of twelve mice in the control group developed diabetes, whereas only three (25 %) out of twelve mice in the EGCG-treated group became diabetic (P < 0·05). Consistently, mice supplemented with EGCG had significantly higher plasma insulin levels and survival rate but lower glycosylated Hb concentrations compared with the control animals. EGCG had no significant effects on food or water intake and body weight in mice, suggesting that the glucose-lowering effect was not due to an alteration in these parameters. While EGCG did not modulate insulitis, it elevated the circulating anti-inflammatory cytokine IL-10 level in NOD mice. These findings demonstrate that EGCG may be a novel, plant-derived compound capable of reducing the risk of T1D.