Browsing by Subject "Alpha-cells"

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    Insulin degrading enzyme is up-regulated in pancreatic β cells by insulin treatment
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Fernández Díaz, Cristina M.; Escobar Curbelo, Luis; López Acosta, J.F.; Lobatón, Carmen D.; Moreno, Alfredo; Sanz Ortega, Julián; Perdomo, Germán; Cózar Castellano, Irene
    Insulin Degrading Enzyme (IDE) is an endopeptidase that degrades insulin and glucagon. Ide gene has been associated with type-2 diabetes mellitus (DM2). However, the physiological role(s) of IDE in glucose homeostasis and its potential therapeutic benefit remain not completely known. To contribute in the understanding of IDE's role in glucose metabolism, we analyzed IDE protein level in pancreatic islets from two hyperinsulinemic mouse models, db/db and high-fat diet (HFD) mice, as well as in human islets from DM2 patients treated with oral hypoglycemic agents (OHAs) or insulin. IDE protein level was detected by staining and by western-blot. INS1E cells, rat and human islets were treated with insulin and IDE protein level was studied. We have shown for the first time IDE staining in rodent and human tissue, using the proper negative control, IDE null mouse tissue. Our staining indicates that IDE is expressed in both beta- and alpha-cells, with higher expression in alpha-cells. Db/db and HFD mice islets showed increased IDE protein level. Interestingly, human islets from DM2 patients treated with OHAs showed decreased IDE protein level in beta-cells. Meanwhile, islets from insulin-treated DM2 patients showed augmented IDE protein level compared to OHAs patients, pointing to an upregulation of IDE protein level stimulated by insulin. These data correlate nicely with insulin-stimulated upregulation of IDE in cultured INS1E cells, as well as in rat and human islets. In conclusion, our study shows that IDE is expressed in pancreatic beta- and alpha-cells of both rodents and humans, having higher expression in alpha-cells. Furthermore, insulin stimulates IDE protein level in pancreatic beta-cells. These results may have implications in how DM2 patient’s treatment affects their beta-cell function.
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    Pancreatic islet (of Langerhans) revisited
    (2019) Mandarim de Lacerda, Carlos A.
    One hundred and fifty years ago, Paul Langerhans described what would come to be known as pancreatic ‘islet of Langerhans’. Since then, we have accumulated knowledge about the pancreatic islet, the cells that exist there and the hormones secreted by these cells. The increasing prevalence of obesity, diabetes and Alzheimer’s disease in the population (three conditions that are linked to pancreatic islet function), the islet has been playing a significant role in endocrinological and metabolic studies searching how we can protect the pancreatic islet and its cell content, or how we can regenerate it. This review will be interested in the most recent and relevant aspects of knowledge regarding the pancreatic islet, always mentioning the evolution of knowledge and future perspectives for the treatment of diabetes and Alzheimer’s disease. The most recent research with microRNAs and islet culture and pseudoislet culture (organoids) allows predicting advances in knowledge with new drugs to act on the islet/cells (such as the hormone glucagon-like peptide (GLP) -1) as well as induction of other islet cells like alpha-cells and delta-cells to transform into beta-cells.