Browsing by Subject "β-cell function"

Now showing 1 - 6 of 6
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    Assessing the Pathophysiology of Hyperglycemia in the Diabetes RElated to Acute Pancreatitis and Its Mechanisms (DREAM) Study: From the Type 1 Diabetes in Acute Pancreatitis Consortium (T1DAPC)
    (Wolters Kluwer, 2022) Dungan, Kathleen M.; Hart, Phil A.; Andersen, Dana K.; Basina, Marina; Chinchilli, Vernon M.; Danielson, Kirstie K.; Evans-Molina, Carmella; Goodarzi, Mark O.; Greenbaum, Carla J.; Kalyani, Rita R.; Laughlin, Maren R.; Pichardo-Lowden, Ariana; Pratley, Richard E.; Serrano, Jose; Sims, Emily K.; Speake, Cate; Yadav, Dhiraj; Bellin, Melena D.; Toledo, Frederico G. S.; Type 1 Diabetes in Acute Pancreatitis Consortium; Medicine, School of Medicine
    Objectives: The metabolic abnormalities that lead to diabetes mellitus (DM) following an episode of acute pancreatitis (AP) have not been extensively studied. This manuscript describes the objectives, hypotheses, and methods of mechanistic studies of glucose metabolism that comprise secondary outcomes of the Diabetes RElated to Acute pancreatitis and its Mechanisms (DREAM) Study. Methods: Three months after an index episode of AP, participants without pre-existing DM will undergo baseline testing with an oral glucose tolerance test. Participants will be followed longitudinally in three sub-cohorts with distinct metabolic tests. In the first and largest subcohort, oral glucose tolerance tests will be repeated 12 months after AP and annually to assess changes in β-cell function, insulin secretion, and insulin sensitivity. In the second, mixed meal tolerance tests will be performed at 3 and 12 months, then annually, and following incident DM to assess incretin and pancreatic polypeptide responses. In the third, frequently-sampled intravenous glucose tolerance tests will be performed at 3 months and 12 months to assess the first-phase insulin response and more precisely measure β-cell function and insulin sensitivity. Conclusions: The DREAM study will comprehensively assess the metabolic and endocrine changes that precede and lead to the development of DM after AP.
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    The Contribution of Transcriptional Coregulators in the Maintenance of β-cell Function and Identity
    (Endocrine Society, 2021) Davidson, Rebecca K.; Kanojia, Sukrati; Spaeth, Jason M.; Biochemistry and Molecular Biology, School of Medicine
    Islet β-cell dysfunction that leads to impaired insulin secretion is a principal source of pathology of diabetes. In type 2 diabetes, this breakdown in β-cell health is associated with compromised islet-enriched transcription factor (TF) activity that disrupts gene expression programs essential for cell function and identity. TF activity is modulated by recruited coregulators that govern activation and/or repression of target gene expression, thereby providing a supporting layer of control. To date, more than 350 coregulators have been discovered that coordinate nucleosome rearrangements, modify histones, and physically bridge general transcriptional machinery to recruited TFs; however, relatively few have been attributed to β-cell function. Here, we will describe recent findings on those coregulators with direct roles in maintaining islet β-cell health and identity and discuss how disruption of coregulator activity is associated with diabetes pathogenesis.
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    Differential loss of β-cell function in youth vs. adults following treatment withdrawal in the Restoring Insulin Secretion (RISE) study
    (Elsevier, 2021) Utzschneider, Kristina M.; Tripputi, Mark T.; Kozedub, Alexandra; Barengolts, Elena; Caprio, Sonia; Cree-Green, Melanie; Edelstein, Sharon L.; El Ghormli, Laure; Hannon, Tamara S.; Mather, Kieren J.; Palmer, Jerry; Nadeau, Kristen J.; RISE Consortium; Medicine, School of Medicine
    Aims: To compare OGTT-derived estimates of β-cell function between youth and adults with impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes after treatment discontinuation in RISE. Methods: Youth (n = 89) and adults (n = 132) were randomized to 3 months glargine followed by 9 months metformin (G/M) or 12 months metformin (MET). Insulin sensitivity and β-cell responses were estimated from 3-hour OGTTs over 21 months. Linear mixed models tested for differences by time and age group within each treatment arm. Results: After treatment withdrawal, HbA1c increased in both youth and adults with a larger net increase in G/M youth vs. adults at 21 months. Among youth, β-cell function decreased starting at 12 months in G/M and 15 months in MET. Among adults, β-cell function remained relatively stable although insulin secretion rates decreased in G/M at 21 months. At 21 months vs. baseline β-cell function declined to a greater extent in youth vs. adults in both the G/M and MET treatment arms. Conclusions: After treatment withdrawal youth demonstrated progressive decline in β-cell function after stopping treatment with either G/M or MET. In contrast, β-cell function in adults remained stable despite an increase in HbA1c over time.
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    Methods for Measuring Risk for Type 2 Diabetes in Youth: the Oral Glucose Tolerance Test (OGTT)
    (Springer, 2018-08) Chen, Melinda E.; Aguirre, Rebecca S.; Hannon, Tamara S.; Pediatrics, School of Medicine
    Purpose of Review The oral glucose tolerance test (OGTT) is used both in clinical practice and research to assess glucose tolerance. In addition, the OGTT is utilized for surrogate measures of insulin sensitivity and the insulin response to enteral glucose and has been widely applied in the evaluation of β-cell dysfunction in obesity, prediabetes, and type 2 diabetes. Here we review the use of the OGTT and the OGTT-derived indices for measurement of risk markers for type 2 diabetes in youth. Recent Findings Advantages of using the OGTT for measures of diabetes risk include its accessibility and the incorporation of physiological contributions of the gut-pancreas axis in the measures of insulin response to glucose. Mathematical modeling expands the potential gains from the OGTT in physiology and clinical research. Disadvantages include individual differences in the rate of glucose absorption that modify insulin responses, imperfect control of the glycemic stimulus, and poor intraindividual reproducibility. Summary Available research suggests the OGTT provides valuable information about the development of impaired glycemic control and β-cell function in obese youth along the spectrum of glucose tolerance.
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    Weight loss and β-cell responses following gastric banding or pharmacotherapy in adults with impaired glucose tolerance or type 2 diabetes: a randomized trial
    (Wiley, 2022) Utzschneider, Kristina M.; Ehrmann, David A.; Arslanian, Silva A.; Barengolts, Elena; Buchanan, Thomas A.; Caprio, Sonia; Edelstein, Sharon L.; Hannon, Tamara S.; Kahn, Steven E.; Kozedub, Alexandra; Mather, Kieren J.; Nadeau, Kristen J.; Sam, Susan; Tripputi, Mark; Xiang, Anny H.; El ghormli, Laure; The RISE Consortium; Medicine, School of Medicine
    Objective: The extent to which weight loss contributes to increases in insulin sensitivity (IS) and β-cell function after surgical or medical intervention has not been directly compared in individuals with impaired glucose tolerance or newly diagnosed type 2 diabetes. Methods: The Restoring Insulin Secretion (RISE) Study included adults in the Beta-Cell Restoration Through Fat Mitigation Study (n = 88 randomized to laparoscopic gastric banding or metformin [MET]) and the Adult Medication Study (n = 267 randomized to placebo, MET, insulin glargine/MET, or liraglutide + MET [L + M]). IS and β-cell responses were measured at baseline and after 12 months by modeling of oral glucose tolerance tests and during arginine-stimulated hyperglycemic clamps. Linear regression models assessed differences between and within treatments over time. Results: BMI decreased in all treatment groups, except placebo, at 12 months. IS increased in all arms except placebo and was inversely correlated with changes in BMI. L + M was the only treatment arm that enhanced multiple measures of β-cell function independent of weight loss. Insulin secretion decreased in the laparoscopic gastric banding arm proportional to increases in IS, with no net benefit on β-cell function. Conclusions: Reducing demand on the β-cell by improving IS through weight loss does not reverse β-cell dysfunction. L + M was the only treatment that enhanced β-cell function.
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    β-Cell Function and Insulin Sensitivity in Youth With Early Type 1 Diabetes From a 2-Hour 7-Sample OGTT
    (The Endocrine Society, 2023) Galderisi, Alfonso; Evans-Molina, Carmella; Martino, Mariangela; Caprio, Sonia; Cobelli, Claudio; Moran, Antoinette; Pediatrics, School of Medicine
    Context: The oral minimal model is a widely accepted noninvasive tool to quantify both β-cell responsiveness and insulin sensitivity (SI) from glucose, C-peptide, and insulin concentrations during a 3-hour 9-point oral glucose tolerance test (OGTT). Objective: Here, we aimed to validate a 2-hour 7-point protocol against the 3-hour OGTT and to test how variation in early sampling frequency impacts estimates of β-cell responsiveness and SI. Methods: We conducted a secondary analysis on 15 lean youth with stage 1 type 1 diabetes (T1D; ≥ 2 islet autoantibodies with no dysglycemia) who underwent a 3-hour 9-point OGTT. The oral minimal model was used to quantitate β-cell responsiveness (φtotal) and insulin sensitivity (SI), allowing assessment of β-cell function by the disposition index (DI = φtotal × SI). Seven- and 5-point 2-hour OGTT protocols were tested against the 3-hour 9-point gold standard to determine agreement between estimates of φtotal and its dynamic and static components, SI, and DI across different sampling strategies. Results: The 2-hour estimates for the disposition index exhibited a strong correlation with 3-hour measures (r = 0.975; P < .001) with similar results for β-cell responsiveness and SI (r = 0.997 and r = 0.982; P < .001, respectively). The agreement of the 3 estimates between the 7-point 2-hour and 9-point 3-hour protocols fell within the 95% CI on the Bland-Altman grid with a median difference of 16.9% (-35.3 to 32.5), 0.2% (-0.6 to 1.3), and 14.9% (-1.4 to 28.3) for DI, φtotal, and SI. Conversely, the 5-point protocol did not provide reliable estimates of φ dynamic and static components. Conclusion: The 2-hour 7-point OGTT is reliable in individuals with stage 1 T1D for assessment of β-cell responsiveness, SI, and DI. Incorporation of these analyses into current 2-hour diabetes staging and monitoring OGTTs offers the potential to more accurately quantify risk of progression in the early stages of T1D.