scholarly journals Combining sitagliptin/metformin with a functional fiber delays diabetes progression in Zucker rats

2014 ◽  
Vol 220 (3) ◽  
pp. 361-373 ◽  
Author(s):  
Raylene A Reimer ◽  
Gary J Grover ◽  
Lee Koetzner ◽  
Roland J Gahler ◽  
Michael R Lyon ◽  
...  
Keyword(s):  
Cell Mass ◽  
Primary Objective ◽  
Zucker Rats ◽  
Β Cell ◽  
Dipeptidyl Peptidase 4 ◽  
Glucose Levels ◽  
Combination Treatments ◽  
Blood Glucose Levels ◽  
Obese Zucker Rat ◽  
Zdf Rats

Our primary objective was to determine whether administering the viscous and fermentable polysaccharide PolyGlycopleX (PGX) with metformin (MET) or sitagliptin/metformin (S/MET) reduces hyperglycemia in Zucker diabetic fatty (ZDF) rats more so than monotherapy of each. Glucose tolerance, adiposity, satiety hormones and mechanisms related to dipeptidyl peptidase 4 activity, gut microbiota and, hepatic and pancreatic histology were examined. Male ZDF rats (9–10 weeks of age) were randomized to: i) cellulose/vehicle (control, C); ii) PGX (5% wt/wt)/vehicle (PGX); iii) cellulose/metformin (200 mg/kg) (MET); iv) cellulose/S/MET (10 mg/kg+200 mg/kg) (S/MET); v) PGX (5%)+MET (200 mg/kg) (PGX+MET); vi) cellulose/sitagliptin/MET (5%)+(10 mg/kg+200 mg/kg) (PGX+S/MET) for 6 weeks. PGX+MET and PGX+S/MET reduced glycemia compared with C and singular treatments (P=0.001). Weekly fasted and fed blood glucose levels were lower in PGX+MET and PGX+S/MET compared with all other groups at weeks 4, 5, and 6 (P=0.001). HbA1c was lower in PGX+S/MET than C, MET, S/MET, and PGX at week 6 (P=0.001). Fat mass was lower and GLP1 was higher in PGX+S/MET compared with all other groups (P=0.001). β-cell mass was highest and islet degeneration lowest in PGX+S/MET. Hepatic lipidosis was significantly lower in PGX+S/MET compared with PGX or S/MET alone. When combined with PGX, both MET and S/MET markedly reduce glycemia; however, PGX+S/MET appears advantageous over PGX+MET in terms of increased β-cell mass and reduced adiposity. Both combination treatments attenuated diabetes in the obese Zucker rat.

scholarly journals Dissecting the Brain/Islet Axis in Metabesity

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 350 ◽  
Author(s):  
Esther Fuente-Martín ◽  
Jose M. Mellado-Gil ◽  
Nadia Cobo-Vuilleumier ◽  
Alejandro Martín-Montalvo ◽  
Silvana Y. Romero-Zerbo ◽  
...  
Keyword(s):  
Common Factor ◽  
Critical Role ◽  
Cell Mass ◽  
Cell Types ◽  
Β Cell ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
High Prevalence ◽  
The Central Nervous System ◽  
Metabolic Dysfunctions

The high prevalence of type 2 diabetes mellitus (T2DM), together with the fact that current treatments are only palliative and do not avoid major secondary complications, reveals the need for novel approaches to treat the cause of this disease. Efforts are currently underway to identify therapeutic targets implicated in either the regeneration or re-differentiation of a functional pancreatic islet β-cell mass to restore insulin levels and normoglycemia. However, T2DM is not only caused by failures in β-cells but also by dysfunctions in the central nervous system (CNS), especially in the hypothalamus and brainstem. Herein, we review the physiological contribution of hypothalamic neuronal and glial populations, particularly astrocytes, in the control of the systemic response that regulates blood glucose levels. The glucosensing capacity of hypothalamic astrocytes, together with their regulation by metabolic hormones, highlights the relevance of these cells in the control of glucose homeostasis. Moreover, the critical role of astrocytes in the response to inflammation, a process associated with obesity and T2DM, further emphasizes the importance of these cells as novel targets to stimulate the CNS in response to metabesity (over-nutrition-derived metabolic dysfunctions). We suggest that novel T2DM therapies should aim at stimulating the CNS astrocytic response, as well as recovering the functional pancreatic β-cell mass. Whether or not a common factor expressed in both cell types can be feasibly targeted is also discussed.

scholarly journals Gastrin induces ductal cell dedifferentiation and β-cell neogenesis after 90% pancreatectomy

2014 ◽  
Vol 223 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Noèlia Téllez ◽  
Eduard Montanya
Keyword(s):  
Cell Mass ◽  
Β Cell ◽  
Neurogenin 3 ◽  
Glucose Levels ◽  
Ductal Cells ◽  
Blood Glucose Levels ◽  
Morphometric Analyses ◽  
Underlying Mechanisms ◽  
Mass Expansion

Induction of β-cell mass regeneration is a potentially curative treatment for diabetes. We have recently found that long-term gastrin treatment results in improved metabolic control and β-cell mass expansion in 95% pancreatectomised (Px) rats. In this study, we investigated the underlying mechanisms of gastrin-induced β-cell mass expansion after Px. After 90%-Px, rats were treated with gastrin (Px+G) or vehicle (Px+V), pancreatic remnants were harvested on days 1, 3, 5, 7, and 14 and used for gene expression, protein immunolocalisation and morphometric analyses. Gastrin- and vehicle-treated Px rats showed similar blood glucose levels throughout the study. Initially, after Px, focal areas of regeneration, showing mesenchymal cells surrounding ductal structures that expressed the cholecystokinin B receptor, were identified. These focal areas of regeneration were similar in size and cell composition in the Px+G and Px+V groups. However, in the Px+G group, the ductal structures showed lower levels of keratin 20 and β-catenin (indicative of duct dedifferentiation) and higher levels of expression of neurogenin 3 and NKX6-1 (indicative of endocrine progenitor phenotype), as compared with Px+V rats. In Px+G rats, β-cell mass and the number of scattered β-cells were significantly increased compared with Px+V rats, whereas β-cell replication and apoptosis were similar in the two groups. These results indicate that gastrin treatment-enhanced dedifferentiation and reprogramming of regenerative ductal cells in Px rats, increased β-cell neogenesis and fostered β-cell mass expansion.

Dynamics of insulin sensitivity, β-cell function, and β-cell mass during the development of diabetes in fa/fa rats

2007 ◽  
Vol 293 (6) ◽  
pp. E1730-E1735 ◽  
Author(s):  
Brian G. Topp ◽  
Laura L. Atkinson ◽  
Diane T. Finegood
Keyword(s):  
Insulin Sensitivity ◽  
Cell Function ◽  
Cell Mass ◽  
Primary Role ◽  
High Fat ◽  
Β Cell ◽  
Glucose Levels ◽  
Β Cell Function ◽  
Zdf Rats ◽  
Secretory Capacity

Both male Zucker Fatty (mZF) and lower-fat-fed female Zucker diabetic fatty (LF-fZDF) rats are obese but remain normoglycemic. Male ZDF (mZDF) and high-fat-fed female ZDF rats (HF-fZDF) are also obese but develop diabetes between 7 and 10 wk of age. Although these models have been well studied, the mechanisms governing the adaptations to obesity in the normoglycemic animals, and the failure of adaptation in the animals that develop diabetes, remain unclear. Here we use quantitative morphometry and our recently developed coupled β-cell mass (βm), insulin, and glucose model to elucidate the dynamics of insulin sensitivity (SI), β-cell secretory capacity (βsc), and βm in these four animal models. Both groups that remained normoglycemic with increasing obesity (mZF, LF-fZDF) exhibited increased βm and constant βsc in response to a falling SI. In rats that developed hyperglycemia (mZDF, HF-fZDF), there was a greater reduction in SI and slower expansion of βm, with constant βsc. βsc decreased after glucose levels rose above 20 mM. Taken together, these data suggest that excessive insulin resistance and insufficient β m adaptation play a primary role in the pathogenesis of diabetes.

scholarly journals Loss of β-cell identity and diabetic phenotype in mice caused by disruption of CNOT3-dependent mRNA deadenylation

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Dina Mostafa ◽  
Akiko Yanagiya ◽  
Eleni Georgiadou ◽  
Yibo Wu ◽  
Theodoros Stylianides ◽  
...  
Keyword(s):  
Cell Function ◽  
Cell Mass ◽  
Cell Maturation ◽  
Β Cells ◽  
Β Cell ◽  
Cell Identity ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Β Cell Function ◽  
And Function

AbstractPancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Defects in β-cell function lead to hyperglycemia and diabetes mellitus. Here, we show that CNOT3, a CCR4–NOT deadenylase complex subunit, is dysregulated in islets in diabetic db/db mice, and that it is essential for murine β cell maturation and identity. Mice with β cell-specific Cnot3 deletion (Cnot3βKO) exhibit impaired glucose tolerance, decreased β cell mass, and they gradually develop diabetes. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes, and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increased expression of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.

scholarly journals Degradation of Incretins and Modulation of Blood Glucose Levels by Periodontopathic Bacterial Dipeptidyl Peptidase 4

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Yuko Ohara-Nemoto ◽  
Manami Nakasato ◽  
Yu Shimoyama ◽  
Tomomi T. Baba ◽  
Takeshi Kobayakawa ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Blood Glucose ◽  
Dipeptidyl Peptidase ◽  
Oral Glucose ◽  
Content Type ◽  
Dipeptidyl Peptidase 4 ◽  
Glucose Levels ◽  
Flight Mass Spectrometry ◽  
Blood Glucose Levels ◽  
Molecular Events

ABSTRACT Severe periodontitis is known to aggravate diabetes mellitus, though molecular events related to that link have not been fully elucidated. Porphyromonas gingivalis, a major pathogen of periodontitis, expresses dipeptidyl peptidase 4 (DPP4), which is involved in regulation of blood glucose levels by cleaving incretins in humans. We examined the enzymatic characteristics of DPP4 from P. gingivalis as well as two other periodontopathic bacteria, Tannerella forsythia and Prevotella intermedia, and determined whether it is capable of regulating blood glucose levels. Cell-associated DPP4 activity was found in those microorganisms, which was effectively suppressed by inhibitors of human DPP4, and molecules sized 73 kDa in P. gingivalis, and 71 kDa in T. forsythia and P. intermedia were immunologically detected. The k cat/Km values of recombinant DPP4s ranged from 721 ± 55 to 1,283 ± 23 μM−1s−1 toward Gly-Pro-4-methylcoumaryl-7-amide (MCA), while those were much lower for His-Ala-MCA. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) analysis showed His/Tyr-Ala dipeptide release from the N termini of incretins, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide, respectively, with the action of microbial DPP4. Moreover, intravenous injection of DPP4 into mice decreased plasma active GLP-1 and insulin levels, accompanied by a substantial elevation in blood glucose over the control after oral glucose administration. These results are the first to show that periodontopathic bacterial DPP4 is capable of modulating blood glucose levels the same as mammalian DPP4; thus, the incidence of periodontopathic bacteremia may exacerbate diabetes mellitus via molecular events of bacterial DPP4 activities.

scholarly journals The Role of the α Cell in the Pathogenesis of Diabetes: A World beyond the Mirror

2021 ◽  
Vol 22 (17) ◽  
pp. 9504
Author(s):  
María Sofía Martínez ◽  
Alexander Manzano ◽  
Luis Carlos Olivar ◽  
Manuel Nava ◽  
Juan Salazar ◽  
...  
Keyword(s):  
Cell Function ◽  
Cell Mass ◽  
Glucagon Secretion ◽  
Endocrine Regulation ◽  
Β Cell ◽  
Cell Hyperplasia ◽  
Dipeptidyl Peptidase 4 ◽  
Dipeptidyl Peptidase 4 Inhibitors ◽  
Glucagon Like Peptide 1 ◽  
Chronic Hyperglycaemia

Type 2 Diabetes Mellitus (T2DM) is one of the most prevalent chronic metabolic disorders, and insulin has been placed at the epicentre of its pathophysiological basis. However, the involvement of impaired alpha (α) cell function has been recognized as playing an essential role in several diseases, since hyperglucagonemia has been evidenced in both Type 1 and T2DM. This phenomenon has been attributed to intra-islet defects, like modifications in pancreatic α cell mass or dysfunction in glucagon’s secretion. Emerging evidence has shown that chronic hyperglycaemia provokes changes in the Langerhans’ islets cytoarchitecture, including α cell hyperplasia, pancreatic beta (β) cell dedifferentiation into glucagon-positive producing cells, and loss of paracrine and endocrine regulation due to β cell mass loss. Other abnormalities like α cell insulin resistance, sensor machinery dysfunction, or paradoxical ATP-sensitive potassium channels (KATP) opening have also been linked to glucagon hypersecretion. Recent clinical trials in phases 1 or 2 have shown new molecules with glucagon-antagonist properties with considerable effectiveness and acceptable safety profiles. Glucagon-like peptide-1 (GLP-1) agonists and Dipeptidyl Peptidase-4 inhibitors (DPP-4 inhibitors) have been shown to decrease glucagon secretion in T2DM, and their possible therapeutic role in T1DM means they are attractive as an insulin-adjuvant therapy.

scholarly journals Prevention of Diabetes in db/db Mice by Dietary Soy Is Independent of Isoflavone Levels

Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5200-5211 ◽  
Author(s):  
Céline Zimmermann ◽  
Christopher R. Cederroth ◽  
Lucie Bourgoin ◽  
Michelangelo Foti ◽  
Serge Nef
Keyword(s):  
Glucose Homeostasis ◽  
Cell Function ◽  
Hepatic Glucose Production ◽  
Cell Mass ◽  
Glucose Production ◽  
Metabolic Effects ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Glucose Levels ◽  
Hepatic Glucose

Abstract Recent evidence points towards the beneficial use of soy proteins and isoflavones to improve glucose control and slow the progression of type 2 diabetes. Here, we used diabetic db/db mice fed a high soy-containing diet (SD) or a casein soy-free diet to investigate the metabolic effects of soy and isoflavones consumption on glucose homeostasis, hepatic glucose production, and pancreatic islet function. Male db/db mice fed with a SD exhibited a robust reduction in hyperglycemia (50%), correlating with a reduction in hepatic glucose production and preserved pancreatic β-cell function. The rapid decrease in fasting glucose levels resulted from an inhibition of gluconeogenesis and an increase in glycolysis in the liver of db/db mice. Soy consumption also prevented the loss of pancreatic β-cell mass and thus improved glucose-stimulated insulin secretion (3-fold), which partly accounted for the overall improvements in glucose homeostasis. Comparison of SD effects on hyperglycemia with differing levels of isoflavones or with purified isoflavones indicate that the beneficial physiological effects of soy are not related to differences in their isoflavone content. Overall, these findings suggest that consumption of soy is beneficial for improving glucose homeostasis and delaying the progression of diabetes in the db/db mice but act independently of isoflavone concentration.

scholarly journals Unacylated ghrelin and obestatin increase islet cell mass and prevent diabetes in streptozotocin-treated newborn rats

2010 ◽  
Vol 45 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Riccarda Granata ◽  
Marco Volante ◽  
Fabio Settanni ◽  
Carlotta Gauna ◽  
Corrado Ghé ◽  
...  
Keyword(s):  
Islet Cell ◽  
Cell Function ◽  
Cell Mass ◽  
Newborn Rats ◽  
Β Cell ◽  
Unacylated Ghrelin ◽  
Insulin Levels ◽  
Glucose Levels ◽  
Pancreatic Insulin ◽  
Β Cell Function

The ghrelin gene products, namely acylated ghrelin (AG), unacylated ghrelin (UAG), and obestatin (Ob), were shown to prevent pancreatic β-cell death and to improve β-cell function under treatment with cytokines, which are major cause of β-cell destruction in diabetes. Moreover, AG had been described previously to prevent streptozotocin (STZ)-induced diabetes in rats; however, the effect of either UAG or Ob has never been examined in this context. In the present study, we investigated the potential of UAG and Ob to increase islet β-cell mass and to reduce diabetes at adult age in STZ-treated neonatal rats. One-day-old rats were injected with STZ and subsequently administered with either AG, UAG or Ob for 7 days. On day 70, plasma glucose levels, plasma and pancreatic insulin levels, pancreatic islet area and number, insulin and pancreatic/duodenal homeobox-1 (Pdx1) gene expression, and antiapoptotic BCL2 protein expression were determined. Similarly to AG, both UAG and Ob counteracted STZ-induced high glucose levels and improved plasma and pancreatic insulin levels, which were reduced by the diabetogenic compound. UAG and Ob increased islet area, islet number, and β-cell mass with respect to STZ treatment alone. Finally, in STZ-treated animals, UAG and Ob up-regulated insulin and Pdx1 mRNA and increased the expression of BCL2 similarly to AG. Taken together, our results suggest that in STZ-treated newborn rats, UAG and Ob improve glucose metabolism and preserve islet cell mass, granting a therapeutic potential in medical conditions associated with impaired β-cell function.

scholarly journals Development and Characteristics of Pancreatic Epsilon Cells

2019 ◽  
Vol 20 (8) ◽  
pp. 1867 ◽  
Author(s):  
Naoaki Sakata ◽  
Gumpei Yoshimatsu ◽  
Shohta Kodama
Keyword(s):  
Transcription Factors ◽  
Blood Glucose ◽  
Endocrine Cells ◽  
Current Evidence ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Ghrelin Gene ◽  
Pancreatic Endocrine Cells

Pancreatic endocrine cells expressing the ghrelin gene and producing the ghrelin hormone were first identified in 2002. These cells, named ε cells, were recognized as the fifth type of endocrine cells. Differentiation of ε cells is induced by various transcription factors, including Nk2 homeobox 2, paired box proteins Pax-4 and Pax6, and the aristaless-related homeobox. Ghrelin is generally considered to be a “hunger hormone” that stimulates the appetite and is produced mainly by the stomach. Although the population of ε cells is small in adults, they play important roles in regulating other endocrine cells, especially β cells, by releasing ghrelin. However, the roles of ghrelin in β cells are complex. Ghrelin contributes to increased blood glucose levels by suppressing insulin release from β cells and is also involved in the growth and proliferation of β cells and the prevention of β cell apoptosis. Despite increasing evidence and clarification of the mechanisms of ε cells over the last 20 years, many questions remain to be answered. In this review, we present the current evidence for the participation of ε cells in differentiation and clarify their characteristics by focusing on the roles of ghrelin.

scholarly journals Hope and fear for new classes of type 2 diabetes drugs: is there preclinical evidence that incretin-based therapies alter pancreatic morphology?

2014 ◽  
Vol 221 (1) ◽  
pp. T43-T61 ◽  
Author(s):  
Benjamin J Lamont ◽  
Sofianos Andrikopoulos
Keyword(s):  
Type 2 Diabetes ◽  
Cell Mass ◽  
Preclinical Studies ◽  
Β Cells ◽  
Β Cell ◽  
Dipeptidyl Peptidase 4 ◽  
Dpp4 Inhibitors ◽  
Natural Progression ◽  
Glucagon Like Peptide 1

Incretin-based therapies appear to offer many advantages over other approaches for treating type 2 diabetes. Some preclinical studies have suggested that chronic activation of glucagon-like peptide 1 receptor (GLP1R) signalling in the pancreas may result in the proliferation of islet β-cells and an increase in β-cell mass. This provided hope that enhancing GLP1 action could potentially alter the natural progression of type 2 diabetes. However, to date, there has been no evidence from clinical trials suggesting that GLP1R agonists or dipeptidyl peptidase-4 (DPP4) inhibitors can increase β-cell mass. Nevertheless, while the proliferative capacity of these agents remains controversial, some studies have raised concerns that they could potentially contribute to the development of pancreatitis and hence increase the risk of pancreatic cancer. Currently, there are very limited clinical data to directly assess these potential benefits and risks of incretin-based therapies. However, a review of the preclinical studies indicates that incretin-based therapies probably have only a limited capacity to regenerate pancreatic β-cells, but may be useful for preserving any remaining β-cells in type 2 diabetes. In addition, the majority of preclinical evidence does not support the notion that GLP1R agonists or DPP4 inhibitors cause pancreatitis.

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