There is little difference in the ability of these questionnaires to identify cases accurately, but none showed high PPVs without a considerable compromise on sensitivity. Hence, the choice of an optimum cut-off score that yields the best balance between sensitivity and PPV may need to be tailored to individual settings, with a higher cut-off being recommended in resource-limited primary-care settings.
Background: Cardiovascular disease (CVD) is the leading cause of mortality in type 1 diabetes (T1D) and relates strongly to insulin resistance (IR). Lean and obese T1D adolescents have marked IR. Metformin improves surrogate markers of IR in T1D, but its effect on directly-measured IR and vascular health in T1D youth is unclear. We hypothesized that 1) T1D adolescents have impaired vascular function, and 2) metformin improves this IR and vascular dysfunction. Methods: T1D adolescents and controls underwent MRI of the ascending (AA) and descending aorta (DA) to assess pulse wave velocity (PWV), relative area change (RAC), maximal (WSSMAX) and time-averaged wall shear stress (WSSTA). T1D participants also underwent assessment of carotid intima-media thickness (cIMT) by ultrasound, brachial distensibility (BrachD) by DynaPulse, fat and lean mass by DXA, fasting labs following overnight glycemic control, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (glucose infusion rate/insulin, [M/I]). T1D adolescents were randomized 1:1 to 3 months of 2000 mg metformin or placebo daily, after which baseline measures were repeated. Results: Forty-eight T1D adolescents ages 12–21 years (40% BMI ≥ 90th%ile; 56% female) and twenty-four nondiabetic controls of similar age, BMI and sex distribution were enrolled. T1D adolescents demonstrated impaired aortic health vs. controls, including elevated AA and DA PWV, reduced AA and DA RAC and elevated AA and DA WSSMAX and WSSTA. T1D adolescents in the metformin vs. placebo group had improved M/I (12.2±3.2 vs. −2.4±3.6 [mg/kg/min]/uIU/uL, p=0.005; 18.6±4.8 vs. −3.4±5.6 [mg/lean kg/min]/uIU/uL, p=0.005) and reduced weight (−0.5±0.5 vs. 1.6±0.5 kg, p=0.004), BMI (−0.2±0.15 vs. 0.4±0.15 kg/m2, p=0.005) and fat mass (−0.7±0.3 vs. 0.6±0.4 kg, p=0.01). M/I also improved in normal-weight participants (11.8±4.4 vs. −4.5±4.4 [mg/kg/min]/uIU/uL, p=0.02, 17.6±6.7 vs. −7.0±6.7 [mg/lean kg/min]/uIU/uL, p=0.02). The metformin group had reduced AA WSSMAX (−0.3±0.4 vs. 1.5±0.5 dyne/cm2, p=0.03), AA PWV, (−1.1±1.20 vs. 4.1±1.6 m/s, p=0.04) and far-wall diastolic cIMT (−0.04±0.01 vs. −0.00±0.01 mm, p=0.049) vs. placebo. Conclusions: T1D adolescents demonstrate IR and impaired vascular health vs. controls. Metformin improves IR, regardless of baseline BMI, and BMI, weight, fat mass, insulin dose, aortic and carotid health in T1D adolescents. Metformin may hold promise as a cardioprotective intervention in T1D.
Epigenetic changes are critical for development and progression of cancers, including breast cancer. Significant progress has been made in the basic understanding of how various epigenetic changes such as DNA methylation, histone modification, miRNA expression, and higher order chromatin structure affect gene expression. The present review will focus on methylation and demethylation of histones. While the acetylation of histones has been at the forefront of well-characterized post-translational modifications of histones, including the development of inhibitors targeting de-acetylating enzymes, the past few years have witnessed a dramatic increase in knowledge regarding the role of histone methylation/demethylation. This is an exciting and rapidly evolving area of research, with much promise for potential clinical intervention in several cancers including breast cancer. We also summarize efforts to identity DNA methylation signatures that could be prognostic and/or predictive markers in breast cancer, focusing on recent studies using genome-wide approaches. Finally, we briefly review the efforts made by both the National Institutes of Health Epigenome Project and The Cancer Genome Atlas, especially highlighting the study of breast cancer epigenetics, exciting technological advances, potential roadblocks, and future directions.
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