Redox Imbalance and the Development of Cystic Fibrosis Diabetes

Cystic fibrosis-related diabetes (CFRD) occurs in almost 20% of teens and 50% of adults. The investigators' long term goal is to determine the cause of CFRD in order to translate this knowledge into therapies aimed at preventing CFRD. Since CFRD and type 2 diabetes share several clinical features and since oxidative stress is a key factor in the development of type 2 diabetes, the investigators explored the role of oxidative stress in CFRD. The investigators discovered a unique CF biochemical signature that they believe could be implicated in the development of CFRD. The investigators found that glucose ingestion in CF teens and young adults causes an acute and profound systemic redox imbalance to the oxidizing state. The degree of redox imbalance was quite severe and would be expected to damage the insulin producing cells as these cells are particularly vulnerable to oxidative stress. Thus, these findings could prove to be a critical factor in the pathogenesis of CFRD. This proposal will test the hypothesis that glucose-induced redox imbalance is an intrinsic, metabolic defect in CF. In addition, because CF people are required to consume a high calorie diet to maintain their weight, the investigators also hypothesize that certain high caloric foods will recapitulate the redox imbalance induced by ingesting glucose and thus hasten the development of CFRD. Specifically, the investigators aim to: * Determine whether young children with CF have glucose-induced redox imbalance * Determine whether eating a meal with a high glycemic index induces acute redox imbalance * Determine whether commonly consumed beverages containing simple sugars (i.e., soda or fruit juice) induce acute redox imbalance