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Biancolin AD, Jeong H, Mak KWY, Yuan Z, Brubaker PL. Disrupted and Elevated Circadian Secretion of Glucagon-Like Peptide-1 in a Murine Model of Type 2 Diabetes. Endocrinology 2022; 163:6649564. [PMID: 35876276 PMCID: PMC9368029 DOI: 10.1210/endocr/bqac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Indexed: 11/19/2022]
Abstract
Metabolism and circadian rhythms are intimately linked, with circadian glucagon-like peptide-1 (GLP-1) secretion by the intestinal L-cell entraining rhythmic insulin release. GLP-1 secretion has been explored in the context of obesogenic diets, but never in a rodent model of type 2 diabetes (T2D). There is also considerable disagreement regarding GLP-1 levels in human T2D. Furthermore, recent evidence has demonstrated decreased expression of the β-cell exocytotic protein secretagogin (SCGN) in T2D. To extend these findings to the L-cell, we administered oral glucose tolerance tests at 6 time points in 4-hour intervals to the high-fat diet/streptozotocin (HFD-STZ) mouse model of T2D. This revealed a 10-fold increase in peak GLP-1 secretion with a phase shift of the peak from the normal feeding period into the fasting-phase. This was accompanied by impairments in the rhythms of glucose, glucagon, mucosal clock genes (Arntl and Cry2), and Scgn. Immunostaining revealed that L-cell GLP-1 intensity was increased in the HFD-STZ model, as was the proportion of L-cells that expressed SCGN; however, this was not found in L-cells from humans with T2D, which exhibited decreased GLP-1 staining but maintained their SCGN expression. Gcg expression in isolated L-cells was increased along with pathways relating to GLP-1 secretion and electron transport chain activity in the HFD-STZ condition. Further investigation into the mechanisms responsible for this increase in GLP-1 secretion may give insights into therapies directed toward upregulating endogenous GLP-1 secretion.
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Affiliation(s)
- Andrew D Biancolin
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Hyerin Jeong
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Kimberly W Y Mak
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Zixuan Yuan
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Patricia L Brubaker
- Correspondence: Patricia L. Brubaker, Ph.D., Rm 3366 Medical Sciences Building, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada.
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Sakornyutthadej N, Mahachoklertwattana P, Chanprasertyothin S, Pongratanakul S, Khlairit P, Poomthavorn P. Beta cell function, incretin hormones, and incretin effect in obese children and adolescents with prediabetes. Pediatr Diabetes 2022; 23:203-211. [PMID: 34913553 DOI: 10.1111/pedi.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/04/2021] [Accepted: 12/12/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Defects of incretin hormones and incretin effect may be underlying mechanisms of abnormal glucose metabolism in youth. OBJECTIVE To assess incretin hormone dynamics during an oral glucose tolerance test (OGTT) and incretin effect in obese children with prediabetes in comparison with those with normal glucose tolerance (NGT). METHODS Overweight and obese children were enrolled and classified according to OGTT results as NGT and prediabetes. Insulin sensitivity, insulin secretion, incretin hormone concentrations during OGTT; and incretin effect derived from OGTT and intravenous glucose tolerance test were determined and compared between NGT and prediabetes groups. RESULTS Sixty-three patients (43 NGT and 20 prediabetes) were enrolled. Their median (interquartile range) age was 12.5 (11.1, 13.8) years. Peak glucagon-like peptide-1 (GLP-1) was demonstrated at 30 min during OGTT and was higher in the prediabetes group (49.2 [35.6, 63.6] versus 36.5 [27.6, 44.2] pmol/L, p = 0.009). However, incremental areas under the curves (iAUCs) of GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) were not different between the two groups. There was no difference in incretin effect between NGT and prediabetes (NGT: 66.5% [60.2%, 77.5%] vs. prediabetes: 70.0% [61.5%, 75.0%], p = 0.645). Incretin effect had positive correlations with iAUCs of both GLP-1 and GIP (GLP-1: r = 0.40, p = 0.004 and GIP: r = 0.37, p = 0.009). CONCLUSIONS Comparing between obese children with prediabetes and NGT, there were no differences in overall incretin hormone changes during OGTT and incretin effect. Incretin effect was positively correlated with iAUCs of GLP-1 and GIP.
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Affiliation(s)
- Natee Sakornyutthadej
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pat Mahachoklertwattana
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | | | - Sarunyu Pongratanakul
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Patcharin Khlairit
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Preamrudee Poomthavorn
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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New insight of obesity-associated NAFLD: Dysregulated “crosstalk” between multi-organ and the liver? Genes Dis 2022. [DOI: 10.1016/j.gendis.2021.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Hira T, Pinyo J, Hara H. What Is GLP-1 Really Doing in Obesity? Trends Endocrinol Metab 2020; 31:71-80. [PMID: 31636017 DOI: 10.1016/j.tem.2019.09.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/28/2019] [Accepted: 09/10/2019] [Indexed: 02/06/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone released in response to meal ingestion and enhances insulin secretion from pancreatic β cells. In several human studies, GLP-1 secretory responses to oral glucose load or a meal were decreased in subjects with obesity, glucose intolerance, or diabetes compared with those in healthy subjects. However, the results of meta-analysis and cohort studies do not necessarily support this concept. Results from animal studies are also inconsistent; in multiple studies, GLP-1 secretory responses to a meal were repeatedly higher in diet-induced obese rats than in control rats. Thus, the postprandial GLP-1 response is not necessarily decreased but rather enhanced during obesity development, which is likely to play a protective role against glucose intolerance.
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Affiliation(s)
- Tohru Hira
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan; Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
| | - Jukkrapong Pinyo
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hiroshi Hara
- Department of Food Science and Human Nutrition, Fuji Women's University, Ishikari, Hokkaido, Japan
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Young E, Nwatu C. Prediabetes in sub-saharan Africa: Pathophysiology, predictors, and prevalence. NIGERIAN JOURNAL OF MEDICINE 2020. [DOI: 10.4103/njm.njm_30_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Smushkin G, Sathananthan A, Man CD, Camilleri M, Cobelli C, Rizza RA, Vella A. Letter to the Editor: "Defects in GLP-1 Response to an Oral Challenge Do Not Play a Significant Role in the Pathogenesis of Prediabetes". J Clin Endocrinol Metab 2019; 104:5106-5107. [PMID: 31074786 DOI: 10.1210/jc.2019-00904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 05/06/2019] [Indexed: 02/13/2023]
Affiliation(s)
- Galina Smushkin
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Airani Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Michael Camilleri
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
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Rehman K, Ali MB, Akash MSH. Genistein enhances the secretion of glucagon-like peptide-1 (GLP-1) via downregulation of inflammatory responses. Biomed Pharmacother 2019; 112:108670. [PMID: 30784939 DOI: 10.1016/j.biopha.2019.108670] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 01/31/2019] [Accepted: 02/04/2019] [Indexed: 02/07/2023] Open
Abstract
Glucagon-like peptide-1 (GLP-1) an incretin hormone, is known to regulate the glucose-mediated insulin secretion. However, reduction in the level of GLP-1 is considered to be a major cause for the reduction of GLP-1-dependent insulin secretory response. Genistein an isoflavone, is an important polyphenol and has wide range of therapeutic potentials, but its therapeutic effects alone and/or in combination with metformin on GLP-1 secretion have not been investigated yet. Hence, we aimed to investigate the stimulatory action of genistein in combination with metformin on GLP-1 via downregulation of inflammatory mediators, hyperlipidemia and hyperglycemia in alloxan-induced diabetic rats. Diabetes was induced in experimental rats by single administration of alloxan intraperitoneally. Metformin (50 mg/kg/day), genistein (20 mg/kg/day) and combination of genistein and metformin was administered in alloxan-induced diabetic rats. We found that genistein alone and/or in combination with metformin significantly increased the serum level (P < 0.01) and tissue content (P < 0.05) of GLP-1 in intestine when compared with that of metformin-treated animals. Similarly, genistein alone and/or in combination with metformin also resulted in normoglycemia (P < 0.001), glucose tolerance (P < 0.01), insulin sensitivity (P < 0.0001), hyperlipidemia (P < 0.01), liver and kidney function biomarkers (P < 0.01) as compared to that of metformin-treated experimental animals. Moreover, genistein alone and/or in combination with metformin also downregulated the inflammatory responses by decreasing the levels of interleuin-6, tumor necrosis factor-α and C-reactive protein in serum (P < 0.05) and intestine (P < 0.001) more efficiently as compared to that of metformin-treated experimental animals. The downregulation of inflammatory responses in intestine, was positively associated with increased secretion of GLP-1 from intestine. Histopathology of pancreas and intestine also showed that genistein significantly improved the deleterious effects of alloxan on pancreas and intestine. Hence, our work provides new insights on the synergistic effects of genistein and metformin on GLP-1 secretion. This may significantly improve the perception for proposing new GLP-1-based synergistic approaches for the treatment of diabetes mellitus.
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Affiliation(s)
- Kanwal Rehman
- Department of Pharmacy, University of Agriculture, Faisalabad, Pakistan
| | - Mehwish Bagh Ali
- Department of Pharmacy, University of Agriculture, Faisalabad, Pakistan
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Pinyo J, Hira T, Hara H. Continuous feeding of a combined high-fat and high-sucrose diet, rather than an individual high-fat or high-sucrose diet, rapidly enhances the glucagon-like peptide-1 secretory response to meal ingestion in diet-induced obese rats. Nutrition 2019; 62:122-130. [PMID: 30878816 DOI: 10.1016/j.nut.2019.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 12/12/2018] [Accepted: 01/08/2019] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Glucagon-like peptide-1 (GLP-1) is secreted by enteroendocrine L-cells in response to nutrient ingestion. To date, GLP-1 secretion in diet-induced obesity is not well characterized. We aimed to examine GLP-1 secretion in response to meal ingestion during the progression of diet-induced obesity and determinewhether a combined high-fat and high-sucrose (HFS) diet, an individual high-fat (HiFat), or a high-sucrose (HiSuc) diet affect adaptive changes in the postprandial GLP-1 response. METHODS Rats were fed a control, HiFat diet (30% weight), HiSuc diet (40% weight), or HFS (30% fat and 40% sucrose) diet for 5 wk. Meal tolerance tests were conducted to determine postprandial glucose, insulin, and GLP-1 responses to standard (control) diet ingestion every 2 wk. RESULTS After 5 wk, body weight gain of the HiFat (232.3 ± 7.8 g; P = 0.021) and HFS groups (228.0 ± 7.8; P = 0.039), but not the HiSuc group (220.3 ± 7.9; P = 0.244), were significantly higher than that of the control group (200.7 ± 5.4 g). In meal tolerance tests after 2 wk, GLP-1 concentration was significantly elevated in the HFS group only (17.2 ± 2.6 pM; P < 0.001) in response to meal ingestions, but the HiFat group (16.6 ± 3.7 pM; P = 0.156) had a similar response as the HFS group. After 4 wk, GLP-1 concentrations were similarly elevated at 15min in the HFS (14.1 ± 4.4; P = 0.010), HiFat (13.2 ± 2.0; P < 0.001), and HiSuc (13.0 ± 3.3; P = 0.016) groups, but the HFS (9.8 ± 1.0; P = 0.019) and HiFat (8.3 ± 1.5; P = 0.010) groups also had significant elevation at 30min. CONCLUSIONS These results demonstrate that the continuous ingestion of excessive fat and sucrose rapidly enhances the GLP-1 secretory response to luminal nutrients, and the HiFat diet may have a potent effect compared with the HiSuc diet on GLP-1 secretory responses. The increment of postprandial GLP-1 and insulinsecretion may have a role in normalizing postprandial glycaemia and slowing the establishment of glucose intolerance.
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Affiliation(s)
- Jukkrapong Pinyo
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Tohru Hira
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan; Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
| | - Hiroshi Hara
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan; Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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Ruetten H, Gebauer M, Raymond RH, Calle RA, Cobelli C, Ghosh A, Robertson RP, Shankar SS, Staten MA, Stefanovski D, Vella A, Wright K, Fryburg DA. Mixed Meal and Intravenous L-Arginine Tests Both Stimulate Incretin Release Across Glucose Tolerance in Man: Lack of Correlation with β Cell Function. Metab Syndr Relat Disord 2018; 16:406-415. [PMID: 30117761 DOI: 10.1089/met.2018.0022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The aims of this study were to 1. define the responses of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucagon, and peptide YY (PYY) to an oral meal and to intravenous L-arginine; and 2. examine correlation of enteroendocrine hormones with insulin secretion. We hypothesized a relationship between circulating incretin concentrations and insulin secretion. METHODS Subjects with normal glucose tolerance (NGT, n = 23), prediabetes (PDM, n = 17), or with type 2 diabetes (T2DM, n = 22) were studied twice, following a mixed test meal (470 kCal) (mixed meal tolerance test [MMTT]) or intravenous L-arginine (arginine maximal stimulation test [AST], 5 g). GLP-1 (total and active), PYY, GIP, glucagon, and β cell function were measured before and following each stimulus. RESULTS Baseline enteroendocrine hormones differed across the glucose tolerance (GT) spectrum, T2DM generally >NGT and PDM. In response to MMTT, total and active GLP-1, GIP, glucagon, and PYY increased in all populations. The incremental area-under-the-curve (0-120 min) of analytes like total GLP-1 were often higher in T2DM compared with NGT and PDM (35-51%; P < 0.05). At baseline glucose, L-arginine increased total and active GLP-1 and glucagon concentrations in all GT populations (all P < 0.05). As expected, the MMTT and AST provoked differential glucose, insulin, and C-peptide responses across GT populations. Baseline or stimulated enteroendocrine hormone concentrations did not consistently correlate with either measure of β cell function. CONCLUSIONS/INTERPRETATION Both MMTT and AST resulted in insulin and enteroendocrine hormone responses across GT populations without consistent correlation between release of incretins and insulin, which is in line with other published research. If a defect is in the enteroendocrine/β cell axis, it is probably reduced response to rather than diminished secretion of enteroendocrine hormones.
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Affiliation(s)
| | | | | | | | - Claudio Cobelli
- 4 Department of Information Engineering, University of Padova , Padova, Italy
| | - Atalanta Ghosh
- 5 Janssen Research and Development , Raritan, New Jersey
| | - R Paul Robertson
- 6 Pacific Northwest Diabetes Institute, University of Washington , Seattle, Washington
| | - Sudha S Shankar
- 7 Lilly Research Laboratories, Lilly Corporate Center , Indianapolis, Indiana
| | | | - Darko Stefanovski
- 9 School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Adrian Vella
- 10 Division of Endocrinology, Mayo Clinic and Foundation , Rochester, Minnesota
| | - Kathryn Wright
- 11 Wright Biomarker Consulting , Gales Ferry, Connecticut
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Koopman ADM, Rutters F, Rauh SP, Nijpels G, Holst JJ, Beulens JW, Alssema M, Dekker JM. Incretin responses to oral glucose and mixed meal tests and changes in fasting glucose levels during 7 years of follow-up: The Hoorn Meal Study. PLoS One 2018; 13:e0191114. [PMID: 29324870 PMCID: PMC5764355 DOI: 10.1371/journal.pone.0191114] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 12/28/2017] [Indexed: 12/25/2022] Open
Abstract
We conducted the first prospective observational study in which we examined the association between incretin responses to an oral glucose tolerance test (OGTT) and mixed meal test (MMT) at baseline and changes in fasting glucose levels 7 years later, in individuals who were non-diabetic at baseline. We used data from the Hoorn Meal Study; a population-based cohort study among 121 subjects, aged 61.0±6.7y. GIP and GLP-1 responses were determined at baseline and expressed as total and incremental area under the curve (tAUC and iAUC). The association between incretin response at baseline and changes in fasting glucose levels was assessed using linear regression. The average change in glucose over 7 years was 0.43 ± 0.5 mmol/l. For GIP, no significant associations were observed with changes in fasting glucose levels. In contrast, participants within the middle and highest tertile of GLP-1 iAUC responses to OGTT had significantly smaller increases (actually decreases) in fasting glucose levels; -0.28 (95% confidence interval: -0.54;-0.01) mmol/l and -0.39 (-0.67;-0.10) mmol/l, respectively, compared to those in the lowest tertile. The same trend was observed for tAUC GLP-1 following OGTT (highest tertile: -0.32 (0.61;-0.04) mmol/l as compared to the lowest tertile). No significant associations were observed for GLP-1 responses following MMT. In conclusion, within our non-diabetic population-based cohort, a low GLP-1 response to OGTT was associated with a steeper increase in fasting glucose levels during 7 years of follow-up. This suggests that a reduced GLP-1 response precedes glucose deterioration and may play a role in the etiology of type 2 diabetes mellitus.
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Affiliation(s)
- A. D. M. Koopman
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of Epidemiology and Biostatistics, VUmc, Amsterdam, the Netherlands
- * E-mail:
| | - F. Rutters
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of Epidemiology and Biostatistics, VUmc, Amsterdam, the Netherlands
| | - S. P. Rauh
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of Epidemiology and Biostatistics, VUmc, Amsterdam, the Netherlands
| | - G. Nijpels
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of General Practice & Elderly Care medicine, VUmc, Amsterdam, the Netherlands
| | - J. J. Holst
- NNF Center for Basic Metabolic Research and Department of Biomedical Sciences, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - J. W. Beulens
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of Epidemiology and Biostatistics, VUmc, Amsterdam, the Netherlands
- Julius Centre for Health Sciences and Primary Care, University Medical Centre, Utrecht, the Netherlands
| | - M. Alssema
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Unilever Research and Development, Vlaardingen, the Netherlands
| | - J. M. Dekker
- EMGO+ Institute for health and care research, VUmc, Amsterdam, the Netherlands
- Department of Epidemiology and Biostatistics, VUmc, Amsterdam, the Netherlands
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Sharma A, Varghese RT, Shah M, Man CD, Cobelli C, Rizza RA, Bailey KR, Vella A. Impaired Insulin Action Is Associated With Increased Glucagon Concentrations in Nondiabetic Humans. J Clin Endocrinol Metab 2018; 103:314-319. [PMID: 29126197 PMCID: PMC5761487 DOI: 10.1210/jc.2017-01197] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/01/2017] [Indexed: 01/18/2023]
Abstract
CONTEXT Abnormal glucagon concentrations contribute to hyperglycemia, but the mechanisms of α-cell dysfunction in prediabetes are unclear. OBJECTIVE We sought to determine the relative contributions of insulin secretion and action to α-cell dysfunction in nondiabetic participants across the spectrum of glucose tolerance. DESIGN This was a cross-sectional study. A subset of participants (n = 120) was studied in the presence and absence of free fatty acid (FFA) elevation, achieved by infusion of Intralipid (Baxter Healthcare, Deerfield, IL) plus heparin, to cause insulin resistance. SETTING An inpatient clinical research unit at an academic medical center. PARTICIPANTS A total of 310 nondiabetic persons participated in this study. INTERVENTIONS Participants underwent a seven-sample oral glucose tolerance test. Subsequently, 120 participants were studied on two occasions. On one day, infusion of Intralipid plus heparin raised FFA. On the other day, participants received glycerol as a control. MAIN OUTCOME MEASURE(S) We examined the relationship of glucagon concentration with indices of insulin action after adjusting for the effects of age, sex, and weight. Subsequently, we sought to determine whether an acute decrease in insulin action, produced by FFA elevation, altered glucagon concentrations in nondiabetic participants. RESULTS Fasting glucagon concentrations correlated positively with fasting insulin and C-peptide concentrations and inversely with insulin action. Fasting glucagon was not associated with any index of β-cell function in response to an oral challenge. As expected, FFA elevation decreased insulin action and also raised glucagon concentrations. CONCLUSIONS In nondiabetic participants, glucagon secretion was altered by changes in insulin action.
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Affiliation(s)
- Anu Sharma
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ron T. Varghese
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Meera Shah
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Chiara Dalla Man
- Department of Information Engineering, Università di Padova, 35131 Padova, Italy
| | - Claudio Cobelli
- Department of Information Engineering, Università di Padova, 35131 Padova, Italy
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Kent R. Bailey
- Biomedical Statistics and Informatics, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Hira T, Suto R, Kishimoto Y, Kanahori S, Hara H. Resistant maltodextrin or fructooligosaccharides promotes GLP-1 production in male rats fed a high-fat and high-sucrose diet, and partially reduces energy intake and adiposity. Eur J Nutr 2017; 57:965-979. [PMID: 28161724 DOI: 10.1007/s00394-017-1381-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 01/10/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE Increasing secretion and production of glucagon-like peptide-1 (GLP-1) by continuous ingestion of certain food components has been expected to prevent glucose intolerance and obesity. In this study, we examined whether a physiological dose (5% weight in diet) of digestion-resistant maltodextrin (RMD) has a GLP-1-promoting effect in rats fed a high-fat and high-sucrose (HFS) diet. METHODS Rats were fed a control diet or the HFS (30% fat, 40% sucrose wt/wt) diet supplemented with 5% RMD or fructooligosaccharides (FOS) for 8 weeks or for 8 days in separated experiments. Glucose tolerance, energy intake, plasma and tissue GLP-1 concentrations, and cecal short-chain fatty acids concentrations were assessed. RESULTS After 4 weeks of feeding, HFS-fed rats had significantly higher glycemic response to oral glucose than control rats, but rats fed HFS + RMD/FOS did not (approx. 50% reduction vs HFS rats). HFS + RMD/FOS-fed rats had higher GLP-1 responses (~twofold) to oral glucose, than control rats. After 8 weeks, visceral adipose tissue weight was significantly higher in HFS-fed rats than control rats, while HFS + RMD/FOS rats had a trend of reduced gain (~50%) of the tissue weight. GLP-1 contents and luminal propionate concentrations in the large intestine increased (>twofold) by adding RMD/FOS to HFS. Eight days feeding of RMD/FOS-supplemented diets reduced energy intake (~10%) and enhanced cecal GLP-1 production (~twofold), compared to HFS diet. CONCLUSIONS The physiological dose of a prebiotic fiber promptly (within 8 days) promotes GLP-1 production in rats fed an obesogenic diet, which would help to prevent excess energy intake and fat accumulation.
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Affiliation(s)
- Tohru Hira
- Laboratory of Nutritional Biochemistry, Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, 060-8589, Japan.
| | - Ryoya Suto
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yuka Kishimoto
- Research & Development, Matsutani Chemical Industry Co., Ltd., Itami, Hyogo, Japan
| | - Sumiko Kanahori
- Research & Development, Matsutani Chemical Industry Co., Ltd., Itami, Hyogo, Japan
| | - Hiroshi Hara
- Laboratory of Nutritional Biochemistry, Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, 060-8589, Japan
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Larsen MP, Torekov SS. Glucagon-Like Peptide 1: A Predictor of Type 2 Diabetes? J Diabetes Res 2017; 2017:7583506. [PMID: 29082261 PMCID: PMC5610892 DOI: 10.1155/2017/7583506] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/30/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The incretin effect is impaired in patients with type 2 diabetes. AIM To assess the relation between the incretin hormone GLP-1 and the prediabetic subtypes: impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and the combined IFG/IGT to investigate whether a low GLP-1 response may be a predictor of prediabetes in adults. METHOD 298 articles were found using a broad search phrase on the PubMed database and after the assessment of titles and abstracts 19 articles were included. RESULTS AND DISCUSSION Studies assessing i-IFG/IFG and i-IGT/IGT found both increased, unaltered, and reduced GLP-1 levels. Studies assessing IFG/IGT found unaltered or reduced GLP-1 levels. When assessing the five studies with the largest sample size, it clearly suggests a decreased GLP-1 response in IFG/IGT subjects. Several other factors (BMI, glucagon, age, and nonesterified fatty acids (NEFA)), including medications (metformin), may also influence the secretion of GLP-1. CONCLUSION This review suggests that the GLP-1 response is a variable in prediabetes possibly due to a varying GLP-1-secreting profile during the development and progression of type 2 diabetes or difference in the measurement technique. Longitudinal prospective studies are needed to assess whether a reduced GLP-1 response is a predictor of diabetes.
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Affiliation(s)
- Matthias Ploug Larsen
- Department of Biomedical Sciences and Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Signe Sørensen Torekov
- Department of Biomedical Sciences and Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen N, Denmark
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Cobelli C, Vella A. Exocrine and Endocrine Interactions in Cystic Fibrosis: A Potential Key to Understanding Insulin Secretion in Health and Disease? Diabetes 2017; 66:20-22. [PMID: 27999103 PMCID: PMC5204318 DOI: 10.2337/dbi16-0049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Claudio Cobelli
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Metabolism, Diabetes, Nutrition, and Internal Medicine, Mayo Clinic, Rochester, MN
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Lee SA, Koh G, Cho SJ, Yoo SY, Chin SO. Correlation of Glypican-4 Level with Basal Active Glucagon-Like Peptide 1 Level in Patients with Type 2 Diabetes Mellitus. Endocrinol Metab (Seoul) 2016; 31:439-445. [PMID: 27704740 PMCID: PMC5053057 DOI: 10.3803/enm.2016.31.3.439] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/17/2016] [Accepted: 07/04/2016] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Previous studies have reported that glypican-4 (GPC4) regulates insulin signaling by interacting with insulin receptor and through adipocyte differentiation. However, GPC4 has not been studied with regard to its effects on clinical factors in patients with type 2 diabetes mellitus (T2DM). We aimed to identify factors associated with GPC4 level in T2DM. METHODS Between January 2010 and December 2013, we selected 152 subjects with T2DM and collected serum and plasma into tubes pretreated with aprotinin and dipeptidyl peptidase-4 inhibitor to preserve active gastric inhibitory polypeptide (GIP) and glucagon-like peptide 1 (GLP-1). GPC4, active GLP-1, active GIP, and other factors were measured in these plasma samples. We performed a linear regression analysis to identify factors associated with GPC4 level. RESULTS The subjects had a mean age of 58.1 years, were mildly obese (mean body mass index [BMI], 26.1 kg/m²), had T2DM of long-duration (mean, 101.3 months), glycated hemoglobin 7.5%, low insulin secretion, and low insulin resistance (mean homeostatic model assessment of insulin resistance [HOMA-IR], 1.2). Their mean GPC4 was 2.0±0.2 ng/mL. In multivariate analysis, GPC4 was independently associated with age (β=0.224, P=0.009), and levels of active GLP-1 (β=0.171, P=0.049) and aspartate aminotransferase (AST; β=-0.176, P=0.043) after being adjusted for other clinical factors. CONCLUSION GPC4 was independently associated with age, active GLP-1, and AST in T2DM patients, but was not associated with HOMA-IR and BMI, which are well known factors related to GPC4. Further study is needed to identify the mechanisms of the association between GPC4 and basal active GLP-1 levels.
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Affiliation(s)
- Sang Ah Lee
- Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea.
| | - Gwanpyo Koh
- Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
| | - Suk Ju Cho
- Department of Anesthesiology, Jeju National University School of Medicine, Jeju, Korea
| | - So Yeon Yoo
- Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
| | - Sang Ouk Chin
- Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
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Suh S, Kim MY, Kim SK, Hur KY, Park MK, Kim DK, Cho NH, Lee MK. Glucose-Dependent Insulinotropic Peptide Level Is Associated with the Development of Type 2 Diabetes Mellitus. Endocrinol Metab (Seoul) 2016; 31:134-41. [PMID: 26676334 PMCID: PMC4803549 DOI: 10.3803/enm.2016.31.1.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/04/2015] [Accepted: 09/15/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Incretin hormone levels as a predictor of type 2 diabetes mellitus have not been fully investigated. Therefore, we measured incretin hormone levels to examine the relationship between circulating incretin hormones, diabetes, and future diabetes development in this study. METHODS A nested case-control study was conducted in a Korean cohort. The study included the following two groups: the control group (n=149), the incident diabetes group (n=65). Fasting total glucagon-like peptide-1 (GLP-1) and total glucose-dependent insulinotropic peptide (GIP) levels were measured and compared between these groups. RESULTS Fasting total GIP levels were higher in the incident diabetes group than in the control group (32.64±22.68 pmol/L vs. 25.54±18.37 pmol/L, P=0.034). There was no statistically significant difference in fasting total GLP-1 levels between groups (1.14±1.43 pmol/L vs. 1.39±2.13 pmol/L, P=0.199). In multivariate analysis, fasting total GIP levels were associated with an increased risk of diabetes (odds ratio, 1.005; P=0.012) independent of other risk factors. CONCLUSION Fasting total GIP levels may be a risk factor for the development of type 2 diabetes mellitus. This association persisted even after adjusting for other metabolic parameters such as elevated fasting glucose, hemoglobin A1c, and obesity in the pre-diabetic period.
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Affiliation(s)
- Sunghwan Suh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Mi Yeon Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo Kyoung Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Kyu Yeon Hur
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Mi Kyoung Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Duk Kyu Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Nam H Cho
- Department of Preventive Medicine, Ajou University School of Medicine, Suwon, Korea.
| | - Moon Kyu Lee
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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van der Stouwe JG, Aeschbacher S, Krisai P, Schoen T, Meyre P, Todd J, Estis J, Risch M, Risch L, Conen D. Plasma levels of glucagon-like peptide 1 and markers of obesity among young and healthy adults. Clin Endocrinol (Oxf) 2015; 83:636-42. [PMID: 25865948 DOI: 10.1111/cen.12789] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/11/2015] [Accepted: 03/31/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Glucagon-like peptide 1 (GLP-1)-related pathways may partially explain the strong relationship between obesity and type 2 diabetes. We therefore aimed to evaluate the relationships between fasting GLP-1 levels, body fat mass and other obesity markers in a large sample of young and healthy adults. DESIGN AND PATIENTS Our population-based study included 2096 individuals aged 24-44. Exclusion criteria were prevalent cardiovascular disease, diabetes or a body mass index (BMI) >35 kg/m(2) . Body fat mass was obtained by bioelectrical impedance analysis. Multivariable linear regression models were constructed to assess the relationships of GLP-1 with various measures of body composition. RESULTS Median age of our population was 37 years, median BMI 24·1 kg/m(2) and median body fat 25·1%. A strong positive correlation was observed in age-adjusted models between GLP-1 and fat mass in men (β (95% confidence interval) 1·38 (0·69; 2·07), P < 0·001) and women (1·27 (0·65; 1·89), P < 0·001) as well as fully adjusted models including BMI in men [0·87 (0·27; 1·46), P < 0·01] but not women [0·29 (-0·07; 0·64), P = 0·11]. The relationships of GLP-1 with BMI for men and women [0·00 (-0·34; 0·34), P = 0·99] [-0·02 (-0·28; 0·25), P = 0·91] and waist circumference [0·43 (-0·45; 1·30), P = 0·34] [0·37 (-0·44; 1·18), P = 0·37], respectively, were not significant after multivariable adjustment including fat mass. CONCLUSION Among young and healthy adults, GLP-1 levels are strongly and independently related to body fat mass especially in men but not BMI or waist circumference. These results raise the hypothesis that GLP-1 may be implicated in body fat mass regulation.
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Affiliation(s)
- Jan Gerrit van der Stouwe
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
| | - Stefanie Aeschbacher
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
| | - Philipp Krisai
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
| | - Tobias Schoen
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
| | - Pascal Meyre
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
| | | | | | - Martin Risch
- Labormedizinisches Zentrum Dr. Risch, Schaan, Liechtenstein
- Division of Laboratory Medicine, Kantonspital Graubünden, Chur, Switzerland
| | - Lorenz Risch
- Labormedizinisches Zentrum Dr. Risch, Schaan, Liechtenstein
- Division of Clinical Biochemistry, Medical University Innsbruck, Innsbruck, Austria
- Private University, Triesen, Liechtenstein
| | - David Conen
- Department of Medicine, University Hospital Basel, Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, Basel, Switzerland
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18
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Vella A, Cobelli C. Defective Glucagon-Like Peptide 1 Secretion in Prediabetes and Type 2 Diabetes Is Influenced by Weight and Sex. Chicken, Egg, or None of the Above? Diabetes 2015; 64:2324-5. [PMID: 26106191 PMCID: PMC4876752 DOI: 10.2337/db15-0292] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
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Postprandial glucagon-like peptide-1 secretion is increased during the progression of glucose intolerance and obesity in high-fat/high-sucrose diet-fed rats. Br J Nutr 2015; 113:1477-88. [PMID: 25827219 DOI: 10.1017/s0007114515000550] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is secreted by distal enteroendocrine cells in response to luminal nutrients, and exerts insulinotropic and anorexigenic effects. Although GLP-1 secretory responses under established obese or diabetic conditions have been studied, it has not been investigated whether or how postprandial GLP-1 responses were affected during the progression of diet-induced obesity. In the present study, a meal tolerance test was performed every week in rats fed a high-fat and high-sucrose (HF/HS) diet to evaluate postprandial glycaemic, insulin and GLP-1 responses. In addition, gastric emptying was assessed by the acetaminophen method. After 8 weeks of HF/HS treatment, portal vein and intestinal mucosa were collected to examine GLP-1 production. Postprandial glucose in response to normal meal ingestion was increased in the HF/HS group within 2 weeks, and its elevation gradually returned close to that of the control group until day 50. Slower postprandial gastric emptying was observed in the HF/HS group on days 6, 13 and 34. Postprandial GLP-1 and insulin responses were increased in the HF/HS group at 7 weeks. Higher portal GLP-1 and insulin levels were observed in the HF/HS group, but mucosal gut hormone mRNA levels were unchanged. These results revealed that the postprandial GLP-1 response to meal ingestion is enhanced during the progression of diet-induced glucose intolerance and obesity in rats. The boosted postprandial GLP-1 secretion by chronic HF/HS diet treatment suggests increased sensitivity to luminal nutrients in the gut, and this may slow the establishment of glucose intolerance and obesity.
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20
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Papaetis GS. Incretin-based therapies in prediabetes: Current evidence and future perspectives. World J Diabetes 2014; 5:817-834. [PMID: 25512784 PMCID: PMC4265868 DOI: 10.4239/wjd.v5.i6.817] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 09/10/2014] [Accepted: 11/10/2014] [Indexed: 02/05/2023] Open
Abstract
The prevalence of type 2 diabetes (T2D) is evolving globally at an alarming rate. Prediabetes is an intermediate state of glucose metabolism that exists between normal glucose tolerance (NGT) and the clinical entity of T2D. Relentless β-cell decline and failure is responsible for the progression from NGT to prediabetes and eventually T2D. The huge burden resulting from the complications of T2D created the need of therapeutic strategies in an effort to prevent or delay its development. The beneficial effects of incretin-based therapies, dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists, on β-cell function in patients with T2D, together with their strictly glucose-depended mechanism of action, suggested their possible use in individuals with prediabetes when greater β-cell mass and function are preserved and the possibility of β-cell salvage is higher. The present paper summarizes the main molecular intracellular mechanisms through which GLP-1 exerts its activity on β-cells. It also explores the current evidence of incretin based therapies when administered in a prediabetic state, both in animal models and in humans. Finally it discusses the safety of incretin-based therapies as well as their possible role in order to delay or prevent T2D.
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Michaliszyn SF, Mari A, Lee S, Bacha F, Tfayli H, Farchoukh L, Ferrannini E, Arslanian S. β-cell function, incretin effect, and incretin hormones in obese youth along the span of glucose tolerance from normal to prediabetes to type 2 diabetes. Diabetes 2014; 63:3846-55. [PMID: 24947360 PMCID: PMC4207396 DOI: 10.2337/db13-1951] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 05/30/2014] [Indexed: 12/22/2022]
Abstract
Using the hyperglycemic and euglycemic clamp, we demonstrated impaired β-cell function in obese youth with increasing dysglycemia. Herein we describe oral glucose tolerance test (OGTT)-modeled β-cell function and incretin effect in obese adolescents spanning the range of glucose tolerance. β-Cell function parameters were derived from established mathematical models yielding β-cell glucose sensitivity (βCGS), rate sensitivity, and insulin sensitivity in 255 obese adolescents (173 with normal glucose tolerance [NGT], 48 with impaired glucose tolerance [IGT], and 34 with type 2 diabetes [T2D]). The incretin effect was calculated as the ratio of the OGTT-βCGS to the 2-h hyperglycemic clamp-βCGS. Incretin and glucagon concentrations were measured during the OGTT. Compared with NGT, βCGS was 30 and 65% lower in youth with IGT and T2D, respectively; rate sensitivity was 40% lower in T2D. Youth with IGT or T2D had 32 and 38% reduced incretin effect compared with NGT in the face of similar changes in GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) in response to oral glucose. We conclude that glucose sensitivity deteriorates progressively in obese youth across the spectrum of glucose tolerance in association with impairment in incretin effect without reduction in GLP-1 or GIP, similar to that seen in adult dysglycemia.
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Affiliation(s)
- Sara F Michaliszyn
- Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Andrea Mari
- CNR Institute of Biomedical Engineering, Padova, Italy
| | - SoJung Lee
- Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Fida Bacha
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | - Hala Tfayli
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Lama Farchoukh
- Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Ele Ferrannini
- Department of Clinical and Experimental Medicine, University of Pisa School of Medicine, Pisa, Italy
| | - Silva Arslanian
- Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA Division of Pediatric Endocrinology, Diabetes and Metabolism, Children's Hospital of Pittsburgh, Pittsburgh, PA
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22
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GLP-1 at physiological concentrations recruits skeletal and cardiac muscle microvasculature in healthy humans. Clin Sci (Lond) 2014; 127:163-70. [PMID: 24552454 DOI: 10.1042/cs20130708] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Muscle microvascular surface area determines substrate and hormonal exchanges between plasma and muscle interstitium. GLP-1 (glucagon-like peptide-1) regulates glucose-dependent insulin secretion and has numerous extrapancreatic effects, including a salutary vascular action. To examine whether GLP-1 recruits skeletal and cardiac muscle microvasculature in healthy humans, 26 overnight-fasted healthy adults received a systemic infusion of GLP-1 (1.2 pmol/kg of body mass per min) for 150 min. Skeletal and cardiac muscle MBV (microvascular blood volume), MFV (microvascular flow velocity) and MBF (microvascular blood flow) were determined at baseline and after 30 and 150 min. Brachial artery diameter and mean flow velocity were measured and total blood flow was calculated before and at the end of the GLP-1 infusion. GLP-1 infusion raised plasma GLP-1 concentrations to the postprandial levels and suppressed plasma glucagon concentrations with a transient increase in plasma insulin concentrations. Skeletal and cardiac muscle MBV and MBF increased significantly at both 30 and 150 min (P<0.05). MFV did not change in skeletal muscle, but decreased slightly in cardiac muscle. GLP-1 infusion significantly increased brachial artery diameter (P<0.005) and flow velocity (P=0.05) at 150 min, resulting in a significant increase in total brachial artery blood flow (P<0.005). We conclude that acute GLP-1 infusion significantly recruits skeletal and cardiac muscle microvasculature in addition to relaxing the conduit artery in healthy humans. This could contribute to increased tissue oxygen, nutrient and insulin delivery and exchange and therefore better prandial glycaemic control and tissue function in humans.
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Role of nutrient-sensing taste 1 receptor (T1R) family members in gastrointestinal chemosensing. Br J Nutr 2014; 111 Suppl 1:S8-15. [DOI: 10.1017/s0007114513002286] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Luminal nutrient sensing by G-protein-coupled receptors (GPCR) expressed on the apical domain of enteroendocrine cells activates intracellular pathways leading to secretion of gut hormones that control vital physiological processes such as digestion, absorption, food intake and glucose homeostasis. The taste 1 receptor (T1R) family of GPCR consists of three members: T1R1; T1R2; T1R3. Expression of T1R1, T1R2 and T1R3 at mRNA and protein levels has been demonstrated in the intestinal tissue of various species. It has been shown that T1R2–T1R3, in association with G-protein gustducin, is expressed in intestinal K and L endocrine cells, where it acts as the intestinal glucose (sweet) sensor. A number of studies have demonstrated that activation of T1R2–T1R3 by natural sugars and artificial sweeteners leads to secretion of glucagon-like peptides 1&2 (GLP-1 and GLP-2) and glucose dependent insulinotropic peptide (GIP). GLP-1 and GIP enhance insulin secretion; GLP-2 increases intestinal growth and glucose absorption. T1R1–T1R3 combination co-expressed on the apical domain of cholecystokinin (CCK) expressing cells is a luminal sensor for a number of l-amino acids; with amino acid-activation of the receptor eliciting CCK secretion. This article focuses on the role of the gut-expressed T1R1, T1R2 and T1R3 in intestinal sweet and l-amino acid sensing. The impact of exploiting T1R2–T1R3 as a nutritional target for enhancing intestinal glucose absorption and gut structural maturity in young animals is also highlighted.
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Madsbad S. The role of glucagon-like peptide-1 impairment in obesity and potential therapeutic implications. Diabetes Obes Metab 2014; 16:9-21. [PMID: 23617798 DOI: 10.1111/dom.12119] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/19/2013] [Accepted: 04/19/2013] [Indexed: 12/20/2022]
Abstract
The hormone glucagon-like peptide-1 (GLP-1) is released from the gut in response to food intake. It acts as a satiety signal, leading to reduced food intake, and also as a regulator of gastric emptying. Furthermore, GLP-1 functions as an incretin hormone, stimulating insulin release and inhibiting glucagon secretion from the pancreas in response to food ingestion. Evidence suggests that the action or effect of GLP-1 may be impaired in obese subjects, even in those with normal glucose tolerance. GLP-1 impairment may help explain the increased gastric emptying and decreased satiety signalling seen in obesity. Incretin impairment, probably associated with reduced insulinotropic potency of GLP-1, is also characteristic of type 2 diabetes (T2D). Therefore, it is possible that incretin impairment may contribute to the pathophysiological bridge between obesity and T2D. This review summarises current knowledge about the pathophysiology and consequences of GLP-1 and incretin impairment in obesity, and examines the evidence for an incretin-related link between obesity and T2D. It also considers the current literature surrounding the novel use of GLP-1 receptor agonists as a treatment for obesity in patients with normoglycaemia, prediabetes and T2D.
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Affiliation(s)
- S Madsbad
- Department of Endocrinology, Hvidovre University Hospital, Hvidovre, Denmark
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25
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Abstract
Observational studies suggest that bariatric surgery is the most effective intervention for achieving a significant and durable weight loss. In patients with type 2 diabetes, such surgery is often associated with remission of their diabetes. The mechanism(s) by which surgeries such as Roux-en-Y Gastric Bypass (RYGB) leads to favorable effects on glucose metabolism remain unknown. RYGB is associated with altered secretion of enteroendocrine hormones, leading to the belief that these hormones contribute to the improvement in insulin secretion and action as well as satiation after this procedure. However, it is important to consider the not insignificant effects of caloric restriction and the mechanical changes to the upper gut in determining the outcomes of such surgery.
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Affiliation(s)
- A. VELLA
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA
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27
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Daly K, Al-Rammahi M, Arora DK, Moran AW, Proudman CJ, Ninomiya Y, Shirazi-Beechey SP. Expression of sweet receptor components in equine small intestine: relevance to intestinal glucose transport. Am J Physiol Regul Integr Comp Physiol 2012; 303:R199-208. [PMID: 22552794 DOI: 10.1152/ajpregu.00031.2012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The heteromeric sweet taste receptor T1R2-T1R3 is expressed on the luminal membrane of certain populations of enteroendocrine cells. Sensing of sugars and other sweet compounds by this receptor activates a pathway in enteroendocrine cells, resulting in secretion of a number of gut hormones, including glucagon-like peptide 2 (GLP-2). This subsequently leads to upregulation in the expression of intestinal Na(+)/glucose cotransporter, SGLT1, and increased intestinal glucose absorption. On the basis of the current information available on the horse genome sequence, it has been proposed that the gene for T1R2 (Tas1R2) is absent in the horse. We show here, however, that horses express both the mRNA and protein for T1R2. Equine T1R2 is most closely homologous to that in the pig and the cow. T1R2 protein, along with T1R3, α-gustducin, and GLP-2 proteins are coexpressed in equine intestinal endocrine cells. Intravenous administration of GLP-2, in rats and pigs, leads to an increase in the expression of SGLT1 in absorptive enterocytes and enhancement in blood glucose concentrations. GLP-2 receptor is expressed in enteric neurons, excluding the direct effect of GLP-2 on enterocytes. However, electric stimulation of enteric neurons generates a neural response leading to SGLT1 upregulation, suggesting that sugar in the intestine activates a reflex increase in the functional expression of SGLT1. Horses possess the ability to upregulate SGLT1 expression in response to increased dietary carbohydrates, and to enhance the capacity of the gut to absorb glucose. The gut sweet receptor provides an accessible target for manipulating the equine gut to absorb glucose (and water), allowing greater energy uptake and hydration for hard-working horses.
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Affiliation(s)
- Kristian Daly
- Epithelial Function and Development Group, Department of Functional and Comparative Genomics, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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Affiliation(s)
- Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota, USA.
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