Objective To determine whether the cystic fibrosis transmembrane conductance regulator (CFTR) is involved in human insulin secretion by assessing the metabolic impact of the new CFTR corrector, ivacaftor. Methods This open-label pilot study was conducted in CF patients with the G551D mutation given new prescriptions for ivacaftor. At baseline and 4 weeks after daily ivacaftor therapy, intravenous (IVGTT) and oral glucose (OGTT) tolerance tests were performed. Results Five patients age 6–52 were studied. After 1 month on ivacaftor, the insulin response to oral glucose improved by 66–178% in all subjects except one with long-standing diabetes. OGTT glucose levels were not lower in the two individuals with diabetes or the two with normal glucose tolerance (NGT), but the glucose tolerance category in the subject with impaired glucose tolerance (IGT) improved to NGT after treatment. In response to intravenous glucose, the only patient whose acute insulin secretion did not improve had newly diagnosed, untreated CFRD. The others improved by 51–346%. Acute insulin secretion was partially restored in two subjects with no measurable acute insulin response at baseline, including the one with IGT and the one with long-standing diabetes. Conclusions This small pilot study suggests there is a direct role of CFTR in human insulin secretion. Larger, long-term longitudinal studies are necessary to determine whether early initiation of CFTR correction, particularly in young children with CF who have not yet lost considerable beta-cell mass, will delay or prevent development of diabetes in this high risk population.

To evaluate the contemporary prevalence of diabetic peripheral neuropathy (DPN) in participants with type 1 diabetes in the T1D Exchange Clinic Registry throughout the U.S. RESEARCH DESIGN AND METHODSDPN was assessed with the Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ) in adults with ‡5 years of type 1 diabetes duration. A score of ‡4 defined DPN. Associations of demographic, clinical, and laboratory factors with DPN were assessed. RESULTSAmong 5,936 T1D Exchange participants (mean 6 SD age 39 6 18 years, median type 1 diabetes duration 18 years [interquartile range 11, 31], 55% female, 88% non-Hispanic white, mean glycated hemoglobin [HbA 1c ] 8.1 6 1.6% [65.3 6 17.5 mmol/mol]), DPN prevalence was 11%. Compared with those without DPN, DPN participants were older, had higher HbA 1c , had longer duration of diabetes, were more likely to be female, and were less likely to have a college education and private insurance (all P < 0.001). DPN participants also were more likely to have cardiovascular disease (CVD) (P < 0.001), worse CVD risk factors of smoking (P 5 0.008), hypertriglyceridemia (P 5 0.002), higher BMI (P 5 0.009), retinopathy (P 5 0.004), reduced estimated glomerular filtration rate (P 5 0.02), and Charcot neuroarthropathy (P 5 0.002). There were no differences in insulin pump or continuous glucose monitor use, although DPN participants were more likely to have had severe hypoglycemia (P 5 0.04) and/or diabetic ketoacidosis (P < 0.001) in the past 3 months. CONCLUSIONSThe prevalence of DPN in this national cohort with type 1 diabetes is lower than in prior published reports but is reflective of current clinical care practices. These data also highlight that nonglycemic risk factors, such as CVD risk factors, severe hypoglycemia, diabetic ketoacidosis, and lower socioeconomic status, may also play a role in DPN development.Diabetic neuropathy is a prevalent complication in patients with diabetes and a major cause of morbidity and mortality (1). Among the various forms of diabetic neuropathy, distal symmetric polyneuropathy (DPN) and diabetic autonomic neuropathies are by far the most studied (1).

Risk of type 1 diabetes at 3 years is high for initially multiple and single Ab+ IT and multiple Ab+ NT. Genetic predisposition, age, and male sex are significant risk factors for development of Ab+ in twins.