Excess Iron Suppresses Adiponectin and Leads to Insulin Insensitivity

摘要

Excess iron stores have been linked to increased risk of type 2 diabetes, but the mechanism underpinning this association is unknown. Although serum ferritin responds to inflammatory stress, a hallmark of diabetes, iron may also increase diabetes risk via alternate mechanisms. Excess iron is associated with impairment of pancreatic β-cell function and decreased insulin secretion and sensitivity, and it is negatively correlated with adiponectin levels. Considering that decreased levels of adiponectin, an insulin-sensitizing cytokine, are correlated with obesity, type 2 diabetes, and insulin resistance, new studies from Gabrielsen et al. sought to determine a mechanistic connection among iron excess, decreased adiponectin, and type 2 diabetes. Experiments in humans showed a negative correlation between serum ferritin and adiponectin, and this relationship was more pronounced in diabetic individuals. In these individuals, serum ferritin levels were two times higher and adiponectin levels were 24% lower than in nondiabetic individuals. Similar correlations were observed in people with the metabolic syndrome, especially those with diabetes.