Expression and function of ATP-dependent potassium channels in zebrafish islet β-cells

ATP-sensitive potassium channels (K(ATP) channels) are critical nutrient sensors in many mammalian tissues. In the pancreas, K(ATP) channels are essential for coupling glucose metabolism to insulin secretion. While orthologous genes for many components of metabolism–secretion coupling in mammals are present in lower vertebrates, their expression, functionality and ultimate impact on body glucose homeostasis are unclear. In this paper, we demonstrate that zebrafish islet β-cells express functional K(ATP) channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. We further show that pharmacological activation of native zebrafish K(ATP) using diazoxide, a specific K(ATP) channel opener, is sufficient to disturb glucose tolerance in adult zebrafish. That β-cell K(ATP) channel expression and function are conserved between zebrafish and mammals illustrates the evolutionary conservation of islet metabolic sensing from fish to humans, and lends relevance to the use of zebrafish to model islet glucose sensing and diseases of membrane excitability such as neonatal diabetes

Assessment of Toxicological Perturbations and Variants of Pancreatic Islet Development in the Zebrafish Model

The pancreatic islets, largely comprised of insulin-producing beta cells, play a critical role in endocrine signaling and glucose homeostasis. Because they have low levels of antioxidant defenses and a high perfusion rate, the endocrine islets may be a highly susceptible target tissue of chemical exposures. However, this endpoint, as well as the integrity of the surrounding exocrine pancreas, is often overlooked in studies of developmental toxicology. Disruption of development by toxicants can alter cell fate and migration, resulting in structural alterations that are difficult to detect in mammalian embryo systems, but that are easily observed in the zebrafish embryo model (Danio rerio). Using endogenously expressed fluorescent protein markers for developing zebrafish beta cells and exocrine pancreas tissue, we documented differences in islet area and incidence rates of islet morphological variants in zebrafish embryos between 48 and 96 h post fertilization (hpf), raised under control conditions commonly used in embryotoxicity assays. We identified critical windows for chemical exposures during which increased incidences of endocrine pancreas abnormalities were observed following exposure to cyclopamine (2–12 hpf), Mono-2-ethylhexyl phthalate (MEHP) (3–48 hpf), and Perfluorooctanesulfonic acid (PFOS) (3–48 hpf). Both islet area and length of the exocrine pancreas were sensitive to oxidative stress from exposure to the oxidant tert-butyl hydroperoxide during a highly proliferative critical window (72 hpf). Finally, pancreatic dysmorphogenesis following developmental exposures is discussed with respect to human disease

Parents' Support for School-Entry Requirements for Human Papillomavirus Vaccination: A National Study

The number of states proposing school-entry requirements for human papillomavirus (HPV) vaccination has increased over the last decade. However, data are currently limited regarding parents' support of such laws. We sought to obtain the first national estimates of parents' support of HPV vaccination school-entry requirements

Embryonic Exposures to Perfluorooctanesulfonic Acid (PFOS) Disrupt Pancreatic Organogenesis in the Zebrafish, Danio rerio

Perfluorooctanesulfonic acid (PFOS) is a ubiquitous environmental contaminant, previously 16 utilized as a non-stick application for consumer products and firefighting foam. It can cross the 17 placenta, and has been repeatedly associated with increased risk for diabetes in epidemiological 18 studies. Here, we sought to establish the hazard posed by embryonic PFOS exposures on the 19 developing pancreas in a model vertebrate embryo, and develop criteria for an adverse outcome 20 pathway (AOP) framework to study the developmental origins of metabolic dysfunction. 21 Zebrafish (Danio rerio) embryos were exposed to 16, 32, or 64 μM PFOS beginning at the mid-22 blastula transition. We assessed embryo health, size, and islet morphology in Tg(insulin-GFP) 23 embryos at 48, 96 and 168 hpf, and pancreas length in Tg(ptf1a-GFP) embryos at 96 and 168 24 hpf. QPCR was used to measure gene expression of endocrine and exocrine hormones, digestive 25 peptides, and transcription factors to determine whether these could be used as a predictive 26 measure in an AOP. Embryos exposed to PFOS showed anomalous islet morphology and 27 decreased islet size and pancreas length in a U-shaped dose-response curve, which resemble 28 congenital defects associated with increased risk for diabetes in humans. Expression of genes 29 encoding islet hormones and exocrine digestive peptides followed a similar pattern, as did total 30 larval growth. Our results demonstrate that embryonic PFOS exposures can disrupt pancreatic 31 organogenesis in ways that mimic human congenital defects known to predispose individuals to 32 diabetes; however, future study of the association between these defects and metabolic 33 dysfunction are needed to establish an improved AOP framework

Provider communication and HPV vaccination: The impact of recommendation quality

Receiving a healthcare provider’s recommendation is a strong predictor of HPV vaccination, but little is known empirically about which types of recommendation are most influential. Thus, we sought to investigate the relationship between recommendation quality and HPV vaccination among U.S. adolescents

Application of the Carolina Framework for Cervical Cancer Prevention

The Carolina Framework for Cervical Cancer Prevention describes 4 main causes of cervical cancer incidence: human papillomavirus (HPV) infection, lack of screening, screening errors, and not receiving follow-up care. We present 2 applications of the Carolina Framework in which we identify high-need counties in North Carolina and generate recommendations for improving prevention efforts

Do correlates of HPV vaccine initiation differ between adolescent boys and girls?

Guidelines now recommend that adolescents routinely receive human papillomavirus (HPV) vaccine. Because little is known about uptake among boys, we assessed HPV vaccine initiation in a population-based sample of adolescent boys and girls

Trends in HPV Vaccine Initiation among Adolescent Females in North Carolina, 2008-2010

To better target future immunization efforts, we assessed trends and disparities in human papillomavirus (HPV) vaccine initiation among female adolescents in North Carolina over 3 years

Opportunities for Increasing HPV Vaccine Provision in School Health Centers

Uptake of HPV vaccine remains low among adolescents in the United States. We sought to assess barriers to HPV vaccine provision in school health centers to inform subsequent interventions

Elevated HbA1c levels and the accumulation of differentiated T cells in CMV+ individuals

Aims/hypothesis Biological ageing of the immune system, or immunosenescence, predicts poor health and increased mortality. A hallmark of immunosenescence is the accumulation of differentiated cytotoxic T cells (CD27−CD45RA+/−; or dCTLs), partially driven by infection with the cytomegalovirus (CMV). Immune impairments reminiscent of immunosenescence are also observed in hyperglycaemia, and in vitro studies have illustrated mechanisms by which elevated glucose can lead to increased dCTLs. This study explored associations between glucose dysregulation and markers of immunosenescence in CMV+ and CMV− individuals. Methods A cross-sectional sample of participants from an occupational cohort study (n = 1,103, mean age 40 years, 88% male) were assessed for HbA1c and fasting glucose levels, diabetes, cardiovascular risk factors (e.g. lipids), numbers of circulating effector memory (EM; CD27−CD45RA−) and CD45RA re-expressing effector memory (EMRA; CD27−CD45RA+) T cells, and CMV infection status. Self-report and physical examination assessed anthropometric, sociodemographic and lifestyle factors. Results Among CMV+ individuals (n = 400), elevated HbA1c was associated with increased numbers of EM (B = 2.75, p \u3c 0.01) and EMRA (B = 2.90, p \u3c 0.01) T cells, which was robust to adjustment for age, sex, sociodemographic variables and lifestyle factors. Elevated EM T cells were also positively associated with total cholesterol (B = 0.04, p \u3c 0.05) after applying similar adjustments. No associations were observed in CMV− individuals. Conclusions/interpretation The present study identified consistent associations of unfavourable glucose and lipid profiles with accumulation of dCTLs in CMV+ individuals. These results provide evidence that the impact of metabolic risk factors on immunity and health can be co-determined by infectious factors, and provide a novel pathway linking metabolic risk factors with accelerated immunosenescence. Electronic supplementary material The online version of this article (doi:10.1007/s00125-015-3731-4) contains peer-reviewed but unedited supplementary material, which is available to authorised users