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Liu QK. Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Front Endocrinol (Lausanne) 2024; 15:1431292. [PMID: 39114288 PMCID: PMC11304055 DOI: 10.3389/fendo.2024.1431292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 07/08/2024] [Indexed: 08/10/2024] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are two incretins that bind to their respective receptors and activate the downstream signaling in various tissues and organs. Both GIP and GLP-1 play roles in regulating food intake by stimulating neurons in the brain's satiety center. They also stimulate insulin secretion in pancreatic β-cells, but their effects on glucagon production in pancreatic α-cells differ, with GIP having a glucagonotropic effect during hypoglycemia and GLP-1 exhibiting glucagonostatic effect during hyperglycemia. Additionally, GIP directly stimulates lipogenesis, while GLP-1 indirectly promotes lipolysis, collectively maintaining healthy adipocytes, reducing ectopic fat distribution, and increasing the production and secretion of adiponectin from adipocytes. Together, these two incretins contribute to metabolic homeostasis, preventing both hyperglycemia and hypoglycemia, mitigating dyslipidemia, and reducing the risk of cardiovascular diseases in individuals with type 2 diabetes and obesity. Several GLP-1 and dual GIP/GLP-1 receptor agonists have been developed to harness these pharmacological effects in the treatment of type 2 diabetes, with some demonstrating robust effectiveness in weight management and prevention of cardiovascular diseases. Elucidating the underlying cellular and molecular mechanisms could potentially usher in the development of new generations of incretin mimetics with enhanced efficacy and fewer adverse effects. The treatment guidelines are evolving based on clinical trial outcomes, shaping the management of metabolic and cardiovascular diseases.
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Affiliation(s)
- Qiyuan Keith Liu
- MedStar Medical Group, MedStar Montgomery Medical Center, Olney, MD, United States
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2
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Moon JH, Choe HJ, Lim S. Pancreatic beta-cell mass and function and therapeutic implications of using antidiabetic medications in type 2 diabetes. J Diabetes Investig 2024; 15:669-683. [PMID: 38676410 PMCID: PMC11143426 DOI: 10.1111/jdi.14221] [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: 01/21/2024] [Revised: 03/23/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Nowadays, the focus of diabetes treatment has switched from lowering the glucose level to preserving glycemic homeostasis and slowing the disease progression. The main pathophysiology of both type 1 diabetes and long-standing type 2 diabetes is pancreatic β-cell mass loss and dysfunction. According to recent research, human pancreatic β-cells possess the ability to proliferate in response to elevated insulin demands. It has been demonstrated that in insulin-resistant conditions in humans, such as obesity or pregnancy, the β-cell mass increases. This ability could be helpful in developing novel treatment approaches to restore a functional β-cell mass. Treatment strategies aimed at boosting β-cell function and mass may be a useful tool for managing diabetes mellitus and stopping its progression. This review outlines the processes of β-cell failure and detail the many β-cell abnormalities that manifest in people with diabetes mellitus. We also go over standard techniques for determining the mass and function of β-cells. Lastly, we provide the therapeutic implications of utilizing antidiabetic drugs in controlling the mass and function of pancreatic β-cells.
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Affiliation(s)
- Joon Ho Moon
- Department of Internal MedicineSeoul National University College of MedicineSeongnamSouth Korea
- Department of Internal MedicineSeoul National University Bundang HospitalSeongnamSouth Korea
| | - Hun Jee Choe
- Department of Internal MedicineHallym University Dongtan Sacred Heart HospitalHwaseongSouth Korea
| | - Soo Lim
- Department of Internal MedicineSeoul National University College of MedicineSeongnamSouth Korea
- Department of Internal MedicineSeoul National University Bundang HospitalSeongnamSouth Korea
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3
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Heckmann ND, Palmer R, Mayfield CK, Gucev G, Lieberman JR, Hong K. Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon. Arthroplast Today 2024; 27:101327. [PMID: 39071832 PMCID: PMC11282421 DOI: 10.1016/j.artd.2024.101327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/08/2023] [Accepted: 01/27/2024] [Indexed: 07/30/2024] Open
Abstract
Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.
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Affiliation(s)
- Nathanael D. Heckmann
- Department of Orthopaedic Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Ryan Palmer
- Department of Orthopaedic Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Cory K. Mayfield
- Department of Orthopaedic Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Gligor Gucev
- Department of Anesthesiology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Jay R. Lieberman
- Department of Orthopaedic Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Kurt Hong
- Center for Clinical Nutrition, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
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Wilbon SS, Kolonin MG. GLP1 Receptor Agonists-Effects beyond Obesity and Diabetes. Cells 2023; 13:65. [PMID: 38201269 PMCID: PMC10778154 DOI: 10.3390/cells13010065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/12/2024] Open
Abstract
Glucagon-like peptide-1 receptor agonists (GLP1RA) have been transformative for patients and clinicians in treating type-2 diabetes and obesity. Drugs of this class, the bioavailability of which is continuously improving, enable weight loss and control blood glucose with minimal unwanted side effects. Since adopting GLP1RA for treating metabolic diseases, animal and clinical studies have revealed their beneficial effects on several other pathologies, including cardiovascular diseases, neurodegeneration, kidney disease, and cancer. A notable commonality between these diseases is their association with older age. Clinical trials and preclinical data suggest that GLP1RA may improve outcomes in these aging-related diseases. Some of the benefits of GLP1RA may be indirect due to their effects on obesity and glucose metabolism. However, there is building evidence that GLP1RA may also act directly on multiple organs implicated in aging-related pathology. This review aims to compile the studies reporting the effects of GLP1RA on aging-related diseases and discuss potential underlying mechanisms.
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Affiliation(s)
| | - Mikhail G. Kolonin
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA;
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5
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Sheth S, Patel A, Foreman M, Mumtaz M, Reddy A, Sharaf R, Sheth S, Lucke-Wold B. The protective role of GLP-1 in neuro-ophthalmology. EXPLORATION OF DRUG SCIENCE 2023; 1:221-238. [PMID: 37711214 PMCID: PMC10501042 DOI: 10.37349/eds.2023.00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/22/2023] [Indexed: 09/16/2023]
Abstract
Despite recent advancements in the field of neuro-ophthalmology, the rising rates of neurological and ophthalmological conditions, mismatches between supply and demand of clinicians, and an aging population underscore the urgent need to explore new therapeutic approaches within the field. Glucagon-like peptide 1 receptor agonists (GLP-1RAs), traditionally used in the treatment of type 2 diabetes, are becoming increasingly appreciated for their diverse applications. Recently, GLP-1RAs have been approved for the treatment of obesity and recognized for their cardioprotective effects. Emerging evidence indicates some GLP-1RAs can cross the blood-brain barrier and may have neuroprotective effects. Therefore, this article aims to review the literature on the neurologic and neuro-ophthalmic role of glucagon-like peptide 1 (GLP-1). This article describes GLP-1 peptide characteristics and the mechanisms mediating its known role in increasing insulin, decreasing glucagon, delaying gastric emptying, and promoting satiety. This article identifies the sources and targets of GLP-1 in the brain and review the mechanisms which mediate its neuroprotective effects, as well as implications for Alzheimer's disease (AD) and Parkinson's disease (PD). Furthermore, the preclinical works which unravel the effects of GLP-1 in ocular dynamics and the preclinical literature regarding GLP-1RA use in the management of several neuro-ophthalmic conditions, including diabetic retinopathy (DR), glaucoma, and idiopathic intracranial hypertension (IIH) are discussed.
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Affiliation(s)
- Sohum Sheth
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Aashay Patel
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Marco Foreman
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Mohammed Mumtaz
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Akshay Reddy
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Ramy Sharaf
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Siddharth Sheth
- College of Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Brandon Lucke-Wold
- Department of Neurosurgery, University of Florida, Gainesville, FL 32608, USA
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Research Progress on Hypoglycemic Mechanisms of Resistant Starch: A Review. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27207111. [PMID: 36296704 PMCID: PMC9610089 DOI: 10.3390/molecules27207111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/07/2022]
Abstract
In recent years, the prevalence of diabetes is on the rise, globally. Resistant starch (RS) has been known as a kind of promising dietary fiber for the prevention or treatment of diabetes. Therefore, it has become a hot topic to explore the hypoglycemic mechanisms of RS. In this review, the mechanisms have been summarized, according to the relevant studies in the recent 15 years. In general, the blood glucose could be regulated by RS by regulating the intestinal microbiota disorder, resisting digestion, reducing inflammation, regulating the hypoglycemic related enzymes and some other mechanisms. Although the exact mechanisms of the beneficial effects of RS have not been fully verified, it is indicated that RS can be used as a daily dietary intervention to reduce the risk of diabetes in different ways. In addition, further research on hypoglycemic mechanisms of RS impacted by the RS categories, the different experimental animals and various dietary habits of human subjects, have also been discussed in this review.
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Georgiadou E, Muralidharan C, Martinez M, Chabosseau P, Akalestou E, Tomas A, Wern FYS, Stylianides T, Wretlind A, Legido-Quigley C, Jones B, Lopez-Noriega L, Xu Y, Gu G, Alsabeeh N, Cruciani-Guglielmacci C, Magnan C, Ibberson M, Leclerc I, Ali Y, Soleimanpour SA, Linnemann AK, Rodriguez TA, Rutter GA. Mitofusins Mfn1 and Mfn2 Are Required to Preserve Glucose- but Not Incretin-Stimulated β-Cell Connectivity and Insulin Secretion. Diabetes 2022; 71:1472-1489. [PMID: 35472764 PMCID: PMC9233298 DOI: 10.2337/db21-0800] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 04/04/2022] [Indexed: 01/21/2023]
Abstract
Mitochondrial glucose metabolism is essential for stimulated insulin release from pancreatic β-cells. Whether mitofusin gene expression, and hence, mitochondrial network integrity, is important for glucose or incretin signaling has not previously been explored. Here, we generated mice with β-cell-selective, adult-restricted deletion knock-out (dKO) of the mitofusin genes Mfn1 and Mfn2 (βMfn1/2 dKO). βMfn1/2-dKO mice displayed elevated fed and fasted glycemia and a more than fivefold decrease in plasma insulin. Mitochondrial length, glucose-induced polarization, ATP synthesis, and cytosolic and mitochondrial Ca2+ increases were all reduced in dKO islets. In contrast, oral glucose tolerance was more modestly affected in βMfn1/2-dKO mice, and glucagon-like peptide 1 or glucose-dependent insulinotropic peptide receptor agonists largely corrected defective glucose-stimulated insulin secretion through enhanced EPAC-dependent signaling. Correspondingly, cAMP increases in the cytosol, as measured with an Epac-camps-based sensor, were exaggerated in dKO mice. Mitochondrial fusion and fission cycles are thus essential in the β-cell to maintain normal glucose, but not incretin, sensing. These findings broaden our understanding of the roles of mitofusins in β-cells, the potential contributions of altered mitochondrial dynamics to diabetes development, and the impact of incretins on this process.
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Affiliation(s)
- Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Charanya Muralidharan
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Michelle Martinez
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Elina Akalestou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Fiona Yong Su Wern
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Theodoros Stylianides
- Centre of Innovative and Collaborative Construction Engineering, Loughborough University, Leicestershire, U.K
| | - Asger Wretlind
- Systems Medicin, Steno Diabetes Center Copenhagen, Copenhagen, Denmark
| | - Cristina Legido-Quigley
- Systems Medicin, Steno Diabetes Center Copenhagen, Copenhagen, Denmark
- Institute of Pharmaceutical Science, Kings College London, London, U.K
| | - Ben Jones
- Section of Endocrinology and Investigative Medicine, Imperial College, London, U.K
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Yanwen Xu
- Department of Cell and Developmental Biology, Program of Developmental Biology, and Vanderbilt Center for Stem Cell Biology, Vanderbilt University, School of Medicine, Nashville, TN
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, Program of Developmental Biology, and Vanderbilt Center for Stem Cell Biology, Vanderbilt University, School of Medicine, Nashville, TN
| | - Nour Alsabeeh
- Department of Physiology, Health Sciences Center, Kuwait University, Kuwait City, Kuwait
| | | | - Christophe Magnan
- Regulation of Glycemia by Central Nervous System, Université de Paris, BFA, UMR 8251, CNRS, Paris, France
| | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Yusuf Ali
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Scott A. Soleimanpour
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
- Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI
| | - Amelia K. Linnemann
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Tristan A. Rodriguez
- Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London, U.K
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Centre of Research of Centre Hospitalier de l'Université de Montréal (CHUM), University of Montreal, Montreal, Quebec, Canada
- Corresponding author: Guy A. Rutter, or
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Peng W, Zhou R, Sun ZF, Long JW, Gong YQ. Novel Insights into the Roles and Mechanisms of GLP-1 Receptor Agonists against Aging-Related Diseases. Aging Dis 2022; 13:468-490. [PMID: 35371594 PMCID: PMC8947838 DOI: 10.14336/ad.2021.0928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/16/2021] [Indexed: 11/01/2022] Open
Abstract
Aging and aging-related diseases have emerged as increasingly severe health and social problems. Therefore, it is imperative to discover novel and effective therapeutics to delay the aging process and to manage aging-related diseases. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), one of the classes of antihyperglycemic drugs, have been recommended to manage type 2 diabetes mellitus (T2DM). Moreover, GLP-1 RAs have been shown to protect against oxidative stress, cellular senescence and chronic inflammation, which are widely accepted as the major risk factors of aging. However, their significance in aging or aging-related diseases has not been elucidated. Herein, we explain the underlying mechanisms and protective roles of GLP-1 RAs in aging from a molecular, cellular and phenotypic perspective. We provide novel insights into the broad prospect of GLP-1 RAs in preventing and treating aging-related diseases. Additionally, we highlight the gaps for further studies in clinical applications of GLP-1 RAs in aging-related diseases. This review forms a basis for further studies on the relationship between aging-related diseases and GLP-1 RAs.
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Affiliation(s)
- Wei Peng
- Department of Gastrointestinal Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Rui Zhou
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Ze-Fang Sun
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Jia-Wei Long
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Yong-Qiang Gong
- Department of Gastrointestinal Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China,Correspondence should be addressed to: Dr. Yong-Qiang Gong, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Hunan, China. E-mail:
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The Potential Roles of Probiotics, Resistant Starch, and Resistant Proteins in Ameliorating Inflammation during Aging (Inflammaging). Nutrients 2022; 14:nu14040747. [PMID: 35215397 PMCID: PMC8879781 DOI: 10.3390/nu14040747] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/29/2022] [Accepted: 02/07/2022] [Indexed: 12/23/2022] Open
Abstract
Aging is typically accompanied by biological and physiological changes that alter cellular functions. Two of the most predominant phenomena in aging include chronic low-grade inflammation (inflammaging) and changes in the gut microbiota composition (dysbiosis). Although a direct causal relationship has not been established, many studies have reported significant reductions in inflammation during aging through well-maintained gut health and microbial balance. Prebiotics and probiotics are known to support gut health and can be easily incorporated into the daily diet. Unfortunately, few studies specifically focus on their significance in reducing inflammation during aging. Therefore, this review summarizes the scientific evidence of the potential roles of probiotics and two types of prebiotics, resistant starch and resistant proteins, in later age. Studies have demonstrated that the oral consumption of bacteria that may contribute to anti-inflammatory response, such as Bifidobacterium spp., Akkermansia munichipilla, and Faecalis praunitzii, contributes significantly to the suppression of pro-inflammatory markers in elderly humans and aged animals. Colonic fermentation of resistant starch and proteins also demonstrates anti-inflammatory activity owing to the production of butyrate and an improvement in the gut microbiota composition. Collectively, probiotics, resistant starch, and resistant proteins have the potential to promote healthy aging.
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Le TD, Nguyen NTP, Nguyen ST, Tran HTT, Nguyen LTH, Duong HH, Nguyen HM, Do BN. Sitagliptin Increases Beta-Cell Function and Decreases Insulin Resistance in Newly Diagnosed Vietnamese Patients with Type 2 Diabetes Mellitus. Diabetes Metab Syndr Obes 2020; 13:2119-2127. [PMID: 32606870 PMCID: PMC7310979 DOI: 10.2147/dmso.s255071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/29/2020] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION To investigate effects of Sitagliptin on the enhancement of beta-cell function, reducing insulin resistance, serum glucagon like peptide-1 (GLP-1) concentrations and blood glucose in patients with type 2 diabetes mellitus (T2D) and suggest one of the underlying mechanisms on beta-cell function and insulin resistance. PATIENTS AND METHODS This was a cross-sectional and observational study in comparison to the control group. A study population of 44 newly diagnosed patients with T2D treated with Sitagliptin with a dose of 100 mg/day for 3 months was analyzed to compare 52 healthy participants. Indices for beta-cell function, peripheral insulin sensitivity, and insulin resistance were calculated with homeostasis model assessment 2 (HOMA2) calculator and compared. Serum GLP-1 concentrations were analyzed, and regression analysis was conducted to find the correlations between GLP-1 and beta-cell function and insulin resistance. RESULTS Newly diagnosed patients with T2D witnessed a significant reduction in beta-cell function, serum GLP-1 concentrations at the time of diagnosis. After treatment with Sitagliptin 100 mg/day, they achieved significant improvements in beta-cell function, peripheral insulin sensitivity and insulin resistance. Serum GLP-1 concentrations were increased significantly to those levels in the control group and correlated with peripheral insulin sensitivity and insulin resistance in patients whose beta-cell functions improved. CONCLUSION Sitagliptin improved beta-cell function, insulin resistance and blood glucose in newly diagnosed patients with T2D. Meanwhile, Sitagliptin ameliorated serum GLP-1 concentrations, which contributed to the enhancement of beta-cell.
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Affiliation(s)
- Tuan Dinh Le
- Department of Internal Medicine, Thai Binh University of Medicine and Pharmacy, Thai Binh, Vietnam
| | - Nga Thi Phi Nguyen
- Department of Endocrinology, Military Hospital 103, Ha Noi, Vietnam
- Department of Rheumatology and Endocrinology, Vietnam Military Medical University, Ha Noi, Vietnam
| | - Son Tien Nguyen
- Department of Endocrinology, Military Hospital 103, Ha Noi, Vietnam
- Department of Rheumatology and Endocrinology, Vietnam Military Medical University, Ha Noi, Vietnam
| | | | | | - Hoang Huy Duong
- Department of Internal Medicine, Thai Binh University of Medicine and Pharmacy, Thai Binh, Vietnam
| | | | - Binh Nhu Do
- Division of Military Science, Military Hospital 103, Ha Noi, Vietnam
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11
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González-Mariscal I, Montoro RA, O'Connell JF, Kim Y, Gonzalez-Freire M, Liu QR, Alfaras I, Carlson OD, Lehrmann E, Zhang Y, Becker KG, Hardivillé S, Ghosh P, Egan JM. Muscle cannabinoid 1 receptor regulates Il-6 and myostatin expression, governing physical performance and whole-body metabolism. FASEB J 2019; 33:5850-5863. [PMID: 30726112 DOI: 10.1096/fj.201801145r] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sarcopenic obesity, the combination of skeletal muscle mass and function loss with an increase in body fat, is associated with physical limitations, cardiovascular diseases, metabolic stress, and increased risk of mortality. Cannabinoid receptor type 1 (CB1R) plays a critical role in the regulation of whole-body energy metabolism because of its involvement in controlling appetite, fuel distribution, and utilization. Inhibition of CB1R improves insulin secretion and insulin sensitivity in pancreatic β-cells and hepatocytes. We have now developed a skeletal muscle-specific CB1R-knockout (Skm-CB1R-/-) mouse to study the specific role of CB1R in muscle. Muscle-CB1R ablation prevented diet-induced and age-induced insulin resistance by increasing IR signaling. Moreover, muscle-CB1R ablation enhanced AKT signaling, reducing myostatin expression and increasing IL-6 secretion. Subsequently, muscle-CB1R ablation increased myogenesis through its action on MAPK-mediated myogenic gene expression. Consequently, Skm-CB1R-/- mice had increased muscle mass and whole-body lean/fat ratio in obesity and aging. Muscle-CB1R ablation improved mitochondrial performance, leading to increased whole-body muscle energy expenditure and improved physical endurance, with no change in body weight. These results collectively show that CB1R in muscle is sufficient to regulate whole-body metabolism and physical performance and is a novel target for the treatment of sarcopenic obesity. -González-Mariscal, I., Montoro, R. A., O'Connell, J. F., Kim, Y., Gonzalez-Freire, M., Liu, Q.-R., Alfaras, I., Carlson, O. D., Lehrmann, E., Zhang, Y., Becker, K. G., Hardivillé, S., Ghosh, P., Egan, J. M. Muscle cannabinoid 1 receptor regulates Il-6 and myostatin expression, governing physical performance and whole-body metabolism.
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Affiliation(s)
- Isabel González-Mariscal
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Rodrigo A Montoro
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Jennifer F O'Connell
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Yoo Kim
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Marta Gonzalez-Freire
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health, Baltimore, Maryland, USA
| | - Qing-Rong Liu
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Irene Alfaras
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health, Baltimore, Maryland, USA
| | - Olga D Carlson
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Elin Lehrmann
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Yongqing Zhang
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Kevin G Becker
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Stéphan Hardivillé
- Unité Propre de Recherche (UMR) 8576-Unité de Glycobiologie Structurale et Fonctionelle (UGSF), Centre National de la Recherche (CNRS), Université Lille, Lille, France
| | - Paritosh Ghosh
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Josephine M Egan
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health (NIH), Baltimore, Maryland, USA
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12
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Doyle ME, Fiori JL, Gonzalez Mariscal I, Liu QR, Goodstein E, Yang H, Shin YK, Santa-Cruz Calvo S, Indig FE, Egan JM. Insulin Is Transcribed and Translated in Mammalian Taste Bud Cells. Endocrinology 2018; 159:3331-3339. [PMID: 30060183 PMCID: PMC6112595 DOI: 10.1210/en.2018-00534] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/19/2018] [Indexed: 12/18/2022]
Abstract
We and others have reported that taste cells in taste buds express many peptides in common with cells in the gut and islets of Langerhans in the pancreas. Islets and taste bud cells express the hormones glucagon and ghrelin, the same ATP-sensitive potassium channel responsible for depolarizing the insulin-secreting β cell during glucose-induced insulin secretion, as well as the propeptide-processing enzymes PC1/3 and PC2. Given the common expression of functionally specific proteins in taste buds and islets, it is surprising that no one has investigated whether insulin is synthesized in taste bud cells. Using immunofluorescence, we demonstrated the presence of insulin in mouse, rat, and human taste bud cells. By detecting the postprocessing insulin molecule C-peptide and green fluorescence protein (GFP) in taste cells of both insulin 1-GFP and insulin 2-GFP mice and the presence of the mouse insulin transcript by in situ hybridization, we further proved that insulin is synthesized in individual taste buds and not taken up from the parenchyma. In addition to our cytology data, we measured the level of insulin transcript by quantitative RT-PCR in the anterior and posterior lingual epithelia. These analyses showed that insulin is translated in the circumvallate and foliate papillae in the posterior, but only insulin transcript was detected in the anterior fungiform papillae of the rodent tongue. Thus, some taste cells are insulin-synthesizing cells generated from a continually replenished source of precursor cells in the adult mammalian lingual epithelium.
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Affiliation(s)
- Máire E Doyle
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Jennifer L Fiori
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Isabel Gonzalez Mariscal
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Qing-Rong Liu
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Erin Goodstein
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Hyekyung Yang
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Yu-Kyong Shin
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Sara Santa-Cruz Calvo
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Fred E Indig
- The Confocal Imaging Facility, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Laboratory of Clinical Investigation/Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
- Correspondence: Josephine M. Egan, MD, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, Maryland 21224. E-mail:
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13
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Shin H, Han JH, Yoon J, Sim HJ, Park TJ, Yang S, Lee EK, Kulkarni RN, Egan JM, Kim W. Blockade of cannabinoid 1 receptor improves glucose responsiveness in pancreatic beta cells. J Cell Mol Med 2018; 22:2337-2345. [PMID: 29431265 PMCID: PMC5867156 DOI: 10.1111/jcmm.13523] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/01/2017] [Indexed: 01/19/2023] Open
Abstract
Cannabinoid 1 receptors (CB1Rs) are expressed in peripheral tissues, including islets of Langerhans, where their function(s) is under scrutiny. Using mouse β-cell lines, human islets and CB1R-null (CB1R-/- ) mice, we have now investigated the role of CB1Rs in modulating β-cell function and glucose responsiveness. Synthetic CB1R agonists diminished GLP-1-mediated cAMP accumulation and insulin secretion as well as glucose-stimulated insulin secretion in mouse β-cell lines and human islets. In addition, silencing CB1R in mouse β cells resulted in an increased expression of pro-insulin, glucokinase (GCK) and glucose transporter 2 (GLUT2), but this increase was lost in β cells lacking insulin receptor. Furthermore, CB1R-/- mice had increased pro-insulin, GCK and GLUT2 expression in β cells. Our results suggest that CB1R signalling in pancreatic islets may be harnessed to improve β-cell glucose responsiveness and preserve their function. Thus, our findings further support that blocking peripheral CB1Rs would be beneficial to β-cell function in type 2 diabetes.
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Affiliation(s)
- Hanho Shin
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Ji Hye Han
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Juhwan Yoon
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Hyo Jung Sim
- School of Life ScienceUlsan National Institute of Science and Technology (UNIST)UlsanSouth Korea
- Center for Genomic IntegrityInstitute for Basic ScienceUlsanSouth Korea
| | - Tae Joo Park
- School of Life ScienceUlsan National Institute of Science and Technology (UNIST)UlsanSouth Korea
- Center for Genomic IntegrityInstitute for Basic ScienceUlsanSouth Korea
| | - Siyoung Yang
- Department of PharmacologyAjou University School of MedicineSuwonSouth Korea
- Department of Biomedical SciencesAjou University Graduate School of MedicineSuwonSouth Korea
| | - Eun Kyung Lee
- Department of BiochemistryCollege of MedicineThe Catholic University of KoreaSeoulSouth Korea
| | - Rohit N. Kulkarni
- Department of Islet Cell and Regenerative BiologyJoslin Diabetes Center and Department of MedicineHarvard Medical SchoolHarvard Stem Cell InstituteBostonMAUSA
| | - Josephine M. Egan
- Laboratory of Clinical InvestigationNational Institute on AgingNational Institutes of HealthBaltimoreMDUSA
| | - Wook Kim
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
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14
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Tasyurek HM, Altunbas HA, Balci MK, Griffith TS, Sanlioglu S. Therapeutic Potential of Lentivirus-Mediated Glucagon-Like Peptide-1 Gene Therapy for Diabetes. Hum Gene Ther 2018; 29:802-815. [PMID: 29409356 DOI: 10.1089/hum.2017.180] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Postprandial glucose-induced insulin secretion from the islets of Langerhans is facilitated by glucagon-like peptide-1 (GLP-1)-a metabolic hormone with insulinotropic properties. Among the variety of effects it mediates, GLP-1 induces delta cell secretion of somatostatin, inhibits alpha cell release of glucagon, reduces gastric emptying, and slows food intake. These events collectively contribute to weight loss over time. During type 2 diabetes (T2DM), however, the incretin response to glucose is reduced and accompanied by a moderate reduction in GLP-1 secretion. To compensate for the reduced incretin effect, a human immunodeficiency virus-based lentiviral vector was generated to deliver DNA encoding human GLP-1 (LentiGLP-1), and the anti-diabetic efficacy of LentiGLP-1 was tested in a high-fat diet/streptozotocin-induced model of T2DM. Therapeutic administration of LentiGLP-1 reduced blood glucose levels in obese diabetic Sprague Dawley rats, along with improving insulin sensitivity and glucose tolerance. Normoglycemia was correlated with increased blood GLP-1 and pancreatic beta cell regeneration in LentiGLP-1-treated rats. Plasma triglyceride levels were also normalized after LentiGLP-1 injection. Collectively, these data suggest the clinical potential of GLP-1 gene transfer therapy for the treatment of T2DM.
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Affiliation(s)
- Hale M Tasyurek
- 1 Human Gene and Cell Therapy Center of Akdeniz University Hospitals , Antalya, Turkey
| | - Hasan Ali Altunbas
- 2 Department of Internal Medicine, Division of Endocrinology and Metabolism, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Mustafa Kemal Balci
- 2 Department of Internal Medicine, Division of Endocrinology and Metabolism, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Thomas S Griffith
- 3 Department of Urology, University of Minnesota , School of Medicine, Minneapolis, Minnesota
| | - Salih Sanlioglu
- 1 Human Gene and Cell Therapy Center of Akdeniz University Hospitals , Antalya, Turkey
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15
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Kennedy G, Hardman RJ, Macpherson H, Scholey AB, Pipingas A. How Does Exercise Reduce the Rate of Age-Associated Cognitive Decline? A Review of Potential Mechanisms. J Alzheimers Dis 2018; 55:1-18. [PMID: 27636853 DOI: 10.3233/jad-160665] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The rate of age-associated cognitive decline varies considerably between individuals. It is important, both on a societal and individual level, to investigate factors that underlie these differences in order to identify those which might realistically slow cognitive decline. Physical activity is one such factor with substantial support in the literature. Regular exercise can positively influence cognitive ability, reduce the rate of cognitive aging, and even reduce the risk of Alzheimer's disease (AD) and other dementias. However, while there is substantial evidence in the extant literature for the effect of exercise on cognition, the processes that mediate this relationship are less clear. This review examines cardiovascular health, production of brain derived neurotrophic factor (BDNF), insulin sensitivity, stress, and inflammation as potential pathways, via which exercise may maintain or improve cognitive functioning, and may be particularly pertinent in the context of the aging brain. A greater understanding of these mechanisms and their potential relationships with exercise and cognition will be invaluable in providing biomarkers for investigating the efficacy of differing exercise regimes on cognitive outcomes.
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Affiliation(s)
- Greg Kennedy
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Roy J Hardman
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Helen Macpherson
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia.,Centre for Physical Activity and Nutrition Research, Deakin University, Melbourne, VIC, Australia
| | - Andrew B Scholey
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Andrew Pipingas
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia
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16
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Yang L, Wang L, Zhu C, Wu J, Yuan Y, Yu L, Xu Y, Xu J, Wang T, Liao Z, Wang S, Zhu X, Gao P, Zhang Y, Wang X, Jiang Q, Shu G. Laminarin counteracts diet-induced obesity associated with glucagon-like peptide-1 secretion. Oncotarget 2017; 8:99470-99481. [PMID: 29245916 PMCID: PMC5725107 DOI: 10.18632/oncotarget.19957] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/16/2017] [Indexed: 01/13/2023] Open
Abstract
Laminarin, a type of β-glucan isolated from brown seaweeds, exhibits verity of physiological activities, which include immunology modulation and antitumor function. To investigate the effect of laminarin on energy homeostasis, mice were orally administrated with laminarin to test food intake, fat deposition, and glucose homeostasis. Chronically, laminarin treatment significantly decreases high-fat-diet-induced body weight gain and fat deposition and reduces blood glucose level and glucose tolerance. Acutely, laminarin enhances serum glucagon-like peptide-1 (GLP-1) content and the mRNA expression level of proglucagon and prohormone convertase 1 in ileum. Subsequently, laminarin suppresses the food intake of mice, the hypothalamic AgRP neuron activity, and AgRP expression but activates pancreatic function. Furthermore, laminarin-induced appetite reduction was totally blocked by Exendin (9-39), a specific competitive inhibitor of GLP-1 receptor. Then, STC-1 cells were adopted to address the underlying mechanism, by which laminarin promoted GLP-1 secretion in vitro. Results showed that laminarin dose-dependently promoted GLP-1 secretion and c-Fos protein expression in STC-1 cells, which were independent of Dectin-1 and CD18. Interestingly, BAPTA-AM, a calcium-chelating agent, potently attenuated laminarin-induced [Ca2+]i elevation, c-Fos expression, and GLP-1 secretion. In summary, our data support that laminarin counteracts diet-induced obesity and stimulates GLP-1 secretion via [Ca2+]i; this finding provides an experimental basis for laminarin application to treat obesity and maintain glucose homeostasis.
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Affiliation(s)
- Liusong Yang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Lina Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Canjun Zhu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Junguo Wu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yexian Yuan
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Lulu Yu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yaqiong Xu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Jingren Xu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Tao Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Zhengrui Liao
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Songbo Wang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Xiaotong Zhu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Ping Gao
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China
| | - Yongliang Zhang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xiuqi Wang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Qingyan Jiang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
| | - Gang Shu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.,South China Observation Experiment Station of Animal Nutrition and Feed Science, Ministry of Agriculture, Guangzhou, Guangdong 510642, China
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17
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GLP-1 receptor independent pathways: emerging beneficial effects of GLP-1 breakdown products. Eat Weight Disord 2017; 22:231-240. [PMID: 28040864 DOI: 10.1007/s40519-016-0352-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/15/2016] [Indexed: 12/26/2022] Open
Abstract
The glucagon-like peptide-1 (GLP-1) axis has emerged as a major therapeutic target for the treatment of type 2 diabetes and, recently, of obesity. The insulinotropic activity of the native incretin hormone GLP-1(7-36)amide, which is mainly exerted through a unique G protein-coupled receptor (GLP-1R), is terminated via enzymatic cleavage by dipeptidyl peptidase-IV that generates a C-terminal GLP-1 metabolite GLP-1(9-36)amide, the major circulating form in plasma. GLP-1(28-36)amide and GLP-1(32-36)amide are further cleavage products derived from GLP-1(7-36)amide and GLP-1(9-36)amide by the action of a neutral endopeptidase known as neprilysin. Until recently, GLP-1-derived metabolites were generally considered metabolically inactive. However, emerging evidence indicates that GLP-1 byproducts have insulinomimetic activities that may contribute to the pleiotropic effects of GLP-1 independently of the canonical GLP-1R. The recent studies reporting the beneficial effects of the administration of these metabolites in vivo and in vitro are the focus of this review. Collectively, these results suggest that GLP-1 metabolites inhibit hepatic glucose production, exert antioxidant cardio- and neuroprotective actions, reduce oxidative stress in vasculature and have both anti-apoptotic and proliferative effects in pancreatic β-cells, putatively by the modulation of mitochondrial functions. These findings have implication in energy homeostasis, obesity and its associated metabolic and cardiovascular complications as well as incretin-based therapies for the treatment of diabetes and obesity.
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18
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Lee PG, Halter JB. The Pathophysiology of Hyperglycemia in Older Adults: Clinical Considerations. Diabetes Care 2017; 40:444-452. [PMID: 28325795 DOI: 10.2337/dc16-1732] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/20/2017] [Indexed: 02/03/2023]
Abstract
Nearly a quarter of older adults in the U.S. have type 2 diabetes, and this population is continuing to increase with the aging of the population. Older adults are at high risk for the development of type 2 diabetes due to the combined effects of genetic, lifestyle, and aging influences. The usual defects contributing to type 2 diabetes are further complicated by the natural physiological changes associated with aging as well as the comorbidities and functional impairments that are often present in older people. This paper reviews the pathophysiology of type 2 diabetes among older adults and the implications for hyperglycemia management in this population.
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Affiliation(s)
- Pearl G Lee
- Geriatric Research Education and Clinical Center, VA Ann Arbor Healthcare System, Ann Arbor, MI .,Division of Geriatric and Palliative Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Jeffrey B Halter
- Division of Geriatric and Palliative Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
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19
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Zhang Y, Song W. Islet amyloid polypeptide: Another key molecule in Alzheimer's pathogenesis? Prog Neurobiol 2017; 153:100-120. [PMID: 28274676 DOI: 10.1016/j.pneurobio.2017.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 02/17/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
Recent epidemiological evidence reveals that patients suffering from type 2 diabetes mellitus (T2DM) often experience a significant decline in cognitive function, and approximately 70% of those cases eventually develop Alzheimer's disease (AD). Although several pathological processes are shared by AD and T2DM, the exact molecular mechanisms connecting these two diseases are poorly understood. Aggregation of human islet amyloid polypeptide (hIAPP), the pathological hallmark of T2DM, has also been detected in brain tissue and is associated with cognitive decline and AD development. In addition, hIAPP and amyloid β protein (Aβ) share many biophysical and physiological properties as well as exert similar cytotoxic mechanisms. Therefore, it is important to examine the possible role of hIAPP in the pathogenesis of AD. In this article, we introduce the basics on this amyloidogenic protein. More importantly, we discuss the potential mechanisms of hIAPP-induced AD development, which will be beneficial for proposing novel and feasible strategies to optimize AD prevention and/or treatment in diabetics.
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Affiliation(s)
- Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
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20
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Hassing HA, Engelstoft MS, Sichlau RM, Madsen AN, Rehfeld JF, Pedersen J, Jones RM, Holst JJ, Schwartz TW, Rosenkilde MM, Hansen HS. Oral 2-oleyl glyceryl ether improves glucose tolerance in mice through the GPR119 receptor. Biofactors 2016; 42:665-673. [PMID: 27297962 DOI: 10.1002/biof.1303] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 05/01/2016] [Accepted: 05/18/2016] [Indexed: 12/26/2022]
Abstract
The intestinal G protein-coupled receptor GPR119 is a novel metabolic target involving glucagon-like peptide-1 (GLP-1)-derived insulin-regulated glucose homeostasis. Endogenous and diet-derived lipids, including N-acylethanolamines and 2-monoacylglycerols (2-MAG) activate GPR119. The purpose of this work is to evaluate whether 2-oleoyl glycerol (2-OG) improves glucose tolerance through GPR119, using wild type (WT) and GPR 119 knock out (KO) mice. We here show that GPR119 is essential for 2-OG-mediated release of GLP-1 and CCK from GLUTag cells, since a GPR119 specific antagonist completely abolished the hormone release. Similarly, in isolated primary colonic crypt cultures from WT mice, GPR119 was required for 2-OG-stimulated GLP-1 release while there was no response in crypts from KO mice. In vivo, gavage with 2-oleyl glyceryl ether ((2-OG ether), a stable 2-OG analog with a potency of 5.3 µM for GPR119 with respect to cAMP formation as compared to 2.3 µM for 2-OG), significantly (P < 0.05) improved glucose clearance in WT littermates, but not in GPR119 KO mice. Finally, deletion of GPR119 in mice resulted in lower glucagon levels, whereas the levels of insulin and GIP were unchanged. In the present study we show that 2-OG stimulates GLP-1 secretion through GPR119 activation in vitro, and that fat-derived 2-MAGs are potent candidates for mediating fat-induced GLP-1 release through GPR119 in vivo. © 2016 BioFactors, 42(6):665-673, 2016.
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Affiliation(s)
- H A Hassing
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, Copenhagen, Denmark
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
| | - M S Engelstoft
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Metabolic Research, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
| | - R M Sichlau
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Metabolic Research, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
| | - A N Madsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
| | - J F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, Blegdamsvej, Copenhagen, Denmark
| | - J Pedersen
- Department of Biomedical Science, Endocrinology Research Section, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
| | - R M Jones
- Arena Pharmaceutical Inc, San Diego, CA, 92121, USA
| | - J J Holst
- Department of Biomedical Science, Endocrinology Research Section, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
- Section for Translational Physiology, Novo Nordisk Foundation Center for Metabolic Research, Panum Institute, Blegdamsvej 3, Copenhagen, Denmark
| | - T W Schwartz
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Metabolic Research, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
| | - M M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
| | - H S Hansen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, Copenhagen, Denmark
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21
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Osborne RI, Ming W, Troutt JS, Siegel RW, Konrad RJ. A dual-monoclonal, sandwich immunoassay specific for glucagon like peptide-19–36/7 (GLP-19–36/7). Clin Biochem 2016; 49:897-902. [DOI: 10.1016/j.clinbiochem.2016.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 11/28/2022]
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22
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Ravnskjaer K, Madiraju A, Montminy M. Role of the cAMP Pathway in Glucose and Lipid Metabolism. Handb Exp Pharmacol 2016; 233:29-49. [PMID: 26721678 DOI: 10.1007/164_2015_32] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
3'-5'-Cyclic adenosine monophosphate (cyclic AMP or cAMP) was first described in 1957 as an intracellular second messenger mediating the effects of glucagon and epinephrine on hepatic glycogenolysis (Berthet et al., J Biol Chem 224(1):463-475, 1957). Since this initial characterization, cAMP has been firmly established as a versatile molecular signal involved in both central and peripheral regulation of energy homeostasis and nutrient partitioning. Many of these effects appear to be mediated at the transcriptional level, in part through the activation of the transcription factor CREB and its coactivators. Here we review current understanding of the mechanisms by which the cAMP signaling pathway triggers metabolic programs in insulin-responsive tissues.
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23
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González-Mariscal I, Krzysik-Walker SM, Kim W, Rouse M, Egan JM. Blockade of cannabinoid 1 receptor improves GLP-1R mediated insulin secretion in mice. Mol Cell Endocrinol 2016; 423:1-10. [PMID: 26724516 PMCID: PMC4752920 DOI: 10.1016/j.mce.2015.12.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 01/18/2023]
Abstract
The cannabinoid 1 receptor (CB1) is an important regulator of energy metabolism. Reports of in vivo and in vitro studies give conflicting results regarding its role in insulin secretion, possibly due to circulatory factors, such as incretins. We hypothesized that this receptor may be a regulator of the entero-insular axis. We found that despite lower food consumption and lower body weight postprandial GLP-1 plasma concentrations were increased in CB1(-/-) mice compared to CB1(+/+) mice administered a standard diet or high fat/sugar diet. Upon exogenous GLP-1 treatment, CB1(-/-) mice had increased glucose-stimulated insulin secretion. In mouse insulinoma cells, cannabinoids reduced GLP-1R-mediated intracellular cAMP accumulation and subsequent insulin secretion. Importantly, such effects were also evident in human islets, and were prevented by pharmacologic blockade of CB1. Collectively, these findings suggest a novel mechanism in which endocannabinoids are negative modulators of incretin-mediated insulin secretion.
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Affiliation(s)
| | | | - Wook Kim
- National Institute on Aging/NIH, 251 Bayview Boulevard, Baltimore, MD 21224, USA; Department of Molecular Science and Technology, Ajou University, Suwan 443-749, South Korea.
| | - Michael Rouse
- National Institute on Aging/NIH, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Josephine M Egan
- National Institute on Aging/NIH, 251 Bayview Boulevard, Baltimore, MD 21224, USA
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24
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Spreckley E, Murphy KG. The L-Cell in Nutritional Sensing and the Regulation of Appetite. Front Nutr 2015; 2:23. [PMID: 26258126 PMCID: PMC4507148 DOI: 10.3389/fnut.2015.00023] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/06/2015] [Indexed: 12/25/2022] Open
Abstract
The gastrointestinal (GI) tract senses the ingestion of food and responds by signaling to the brain to promote satiation and satiety. Representing an important part of the gut-brain axis, enteroendocrine L-cells secrete the anorectic peptide hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in response to the ingestion of food. The release of GLP-1 has multiple effects, including the secretion of insulin from pancreatic β-cells, decreased gastric emptying, and increased satiation. PYY also slows GI motility and reduces food intake. At least part of the gut-brain response seems to be due to direct sensing of macronutrients by L-cells, by mechanisms including specific nutrient-sensing receptors. Such receptors may represent possible pathways to target to decrease appetite and increase energy expenditure. Designing drugs or functional foods to exploit the machinery of these nutrient-sensing mechanisms may offer a potential approach for agents to treat obesity and metabolic disease.
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Affiliation(s)
- Eleanor Spreckley
- Section of Investigative Medicine, Department of Medicine, Imperial College London, Hammersmith Hospital , London , UK
| | - Kevin Graeme Murphy
- Section of Investigative Medicine, Department of Medicine, Imperial College London, Hammersmith Hospital , London , UK
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Lamming DW. Diminished mTOR signaling: a common mode of action for endocrine longevity factors. SPRINGERPLUS 2014; 3:735. [PMID: 25674466 PMCID: PMC4320218 DOI: 10.1186/2193-1801-3-735] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 12/07/2014] [Indexed: 12/12/2022]
Abstract
Since the initial observation that a calorie-restricted (CR) diet can extend rodent lifespan, many genetic and pharmaceutical interventions that also extend lifespan in mammals have been discovered. The mechanism by which CR and these other interventions extend lifespan is the subject of significant debate and research. One proposed mechanism is that CR promotes longevity by increasing insulin sensitivity, but recent findings that dissociate longevity and insulin sensitivity cast doubt on this hypothesis. These findings can be reconciled if longevity is promoted not via increased insulin sensitivity, but instead via decreased PI3K/Akt/mTOR pathway signaling. This review presents a unifying hypothesis that explains the lifespan-extending effects of a variety of genetic mutations and pharmaceutical interventions and points towards new molecular pathways which may also be leveraged to promote healthy aging.
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Affiliation(s)
- Dudley W Lamming
- Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin USA ; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin USA
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Abstract
The goal for the treatment of patients with diabetes has today shifted from merely reducing glucose concentrations to preventing the natural decline in β-cell function and delay the progression of disease. Pancreatic β-cell dysfunction and decreased β-cell mass are crucial in the development of diabetes. The β-cell defects are the main pathogenesis in patients with type 1 diabetes and are associated with type 2 diabetes as the disease progresses. Recent studies suggest that human pancreatic β-cells have a capacity for increased proliferation according to increased demands for insulin. In humans, β-cell mass has been shown to increase in patients showing insulin-resistance states such as obesity or in pregnancy. This capacity might be useful for identifying new therapeutic strategies to reestablish a functional β-cell mass. In this context, therapeutic approaches designed to increase β-cell mass might prove a significant way to manage diabetes and prevent its progression. This review describes the various β-cell defects that appear in patients with diabetes and outline the mechanisms of β-cell failure. We also review common methods for assessing β-cell function and mass and methodological limitations in vivo. Finally, we discuss the current therapeutic approaches to improve β-cell function and increase β-cell mass.
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Affiliation(s)
- Kyong Yeun Jung
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Kyoung Min Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Soo Lim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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Yamazaki S, Satoh H, Watanabe T. Liraglutide enhances insulin sensitivity by activating AMP-activated protein kinase in male Wistar rats. Endocrinology 2014; 155:3288-301. [PMID: 24949659 DOI: 10.1210/en.2013-2157] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We investigated the effects of liraglutide on insulin sensitivity and glucose metabolism in male Wistar rats. The rats were fed a normal chow diet (NCD) or a 60% high-fat diet (HFD) for a total of 4 weeks. After 3 weeks of feeding, they were injected with liraglutide once a day for 7 days. Subsequently, euglycemic-hyperinsulinemic clamp studies were performed after fasting the animals for 8 hours. During the clamp studies on the NCD-fed rats, the glucose infusion rate required for euglycemia was significantly higher in the liraglutide group than in the control group. The clamp hepatic glucose output was significantly lower in the liraglutide group than in the control group, but the insulin-stimulated glucose disposal rate did not change significantly in the liraglutide groups. The clamp studies on the HFD-fed rats revealed that the glucose infusion rate required to achieve euglycemia was significantly higher in the liraglutide group than in the control HFD group, and the insulin-stimulated glucose disposal rate increased significantly in the liraglutide groups. The clamp hepatic glucose output decreased significantly in the liraglutide groups. Consistent with the clamp data, the insulin-stimulated phosphorylation of Akt and AMP-activated protein kinase was enhanced in the livers of the NCD- and HFD-fed rats and in the skeletal muscles of the HFD-fed rats. Oil red O staining indicated that liraglutide also improved hepatic steatosis. In summary, our studies suggest that in normal glucose tolerance states, liraglutide enhances insulin sensitivity in the liver but not in skeletal muscles. However, in insulin-resistant states, liraglutide improves insulin resistance in the liver and muscles and improves fatty liver.
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Affiliation(s)
- Satoru Yamazaki
- Department of Nephrology, Hypertension, Diabetology, Endocrinology, and Metabolism, Fukushima Medical University, Fukushima 960-1295, Japan
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We are ageing. BIOMED RESEARCH INTERNATIONAL 2014; 2014:808307. [PMID: 25045704 PMCID: PMC4090574 DOI: 10.1155/2014/808307] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 05/27/2014] [Accepted: 05/27/2014] [Indexed: 02/01/2023]
Abstract
Ageing and longevity is unquestioningly complex. Several thoughts and mechanisms of ageing such as pathways involved in oxidative stress, lipid and glucose metabolism, inflammation, DNA damage and repair, growth hormone axis and insulin-like growth factor (GH/IGF), and environmental exposure have been proposed. Also, some theories of ageing were introduced. To date, the most promising leads for longevity are caloric restriction, particularly target of rapamycin (TOR), sirtuins, hexarelin and hormetic responses. This review is an attempt to analyze the mechanisms and theories of ageing and achieving longevity.
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Abstract
Glucagon-like peptide (GLP)-1 is an incretin hormone with several antidiabetic functions including stimulation of glucose-dependent insulin secretion, increase in insulin gene expression and beta-cell survival. Despite the initial technical difficulties and profound inefficiency of direct gene transfer into the pancreas that seriously restricted in vivo gene transfer experiments with GLP-1, recent exploitation of various routes of gene delivery and alternative means of gene transfer has permitted the detailed assessment of the therapeutic efficacy of GLP-1 in animal models of type 2 diabetes (T2DM). As a result, many clinical benefits of GLP-1 peptide/analogues observed in clinical trials involving induction of glucose tolerance, reduction of hyperglycaemia, suppression of appetite and food intake linked to weight loss have been replicated in animal models using gene therapy. Furthermore, GLP-1-centered gene therapy not only improved insulin sensitivity, but also reduced abdominal and/or hepatic fat associated with obesity-induced T2DM with drastic alterations in adipokine profiles in treated subjects. Thus, a comprehensive assessment of recent GLP-1-mediated gene therapy approaches with detailed analysis of current hurdles and resolutions, is discussed.
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Greig NH, Tweedie D, Rachmany L, Li Y, Rubovitch V, Schreiber S, Chiang YH, Hoffer BJ, Miller J, Lahiri DK, Sambamurti K, Becker RE, Pick CG. Incretin mimetics as pharmacologic tools to elucidate and as a new drug strategy to treat traumatic brain injury. Alzheimers Dement 2014; 10:S62-75. [PMID: 24529527 PMCID: PMC4201593 DOI: 10.1016/j.jalz.2013.12.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 01/12/2023]
Abstract
Traumatic brain injury (TBI), either as an isolated injury or in conjunction with other injuries, is an increasingly common event. An estimated 1.7 million injuries occur within the USA each year and 10 million people are affected annually worldwide. Indeed, nearly one third (30.5%) of all injury-related deaths in the USA are associated with TBI, which will soon outpace many common diseases as the major cause of death and disability. Associated with a high morbidity and mortality and no specific therapeutic treatment, TBI has become a pressing public health and medical problem. The highest incidence of TBI occurs in young adults (15-24 years age) and in the elderly (≥75 years of age). Older individuals are particularly vulnerable to these types of injury, often associated with falls, and have shown increased mortality and worse functional outcome after lower initial injury severity. In addition, a new and growing form of TBI, blast injury, associated with the detonation of improvised explosive devices in the war theaters of Iraq and Afghanistan, are inflicting a wave of unique casualties of immediate impact to both military personnel and civilians, for which long-term consequences remain unknown and may potentially be catastrophic. The neuropathology underpinning head injury is becoming increasingly better understood. Depending on severity, TBI induces immediate neuropathologic effects that, for the mildest form, may be transient; however, with increasing severity, these injuries cause cumulative neural damage and degeneration. Even with mild TBI, which represents the majority of cases, a broad spectrum of neurologic deficits, including cognitive impairments, can manifest that may significantly influence quality of life. Further, TBI can act as a conduit to longer term neurodegenerative disorders. Prior studies of glucagon-like peptide-1 (GLP-1) and long-acting GLP-1 receptor agonists have demonstrated neurotrophic/neuroprotective activities across a broad spectrum of cellular and animal models of chronic neurodegenerative (Alzheimer's and Parkinson's diseases) and acute cerebrovascular (stroke) disorders. In view of the mechanisms underpinning these disorders as well as TBI, we review the literature and recent studies assessing GLP-1 receptor agonists as a potential treatment strategy for mild to moderate TBI.
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Affiliation(s)
- Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
| | - David Tweedie
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Lital Rachmany
- Department of Anatomy & Anthropology, Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Yazhou Li
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Vardit Rubovitch
- Department of Anatomy & Anthropology, Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Shaul Schreiber
- Department of Psychiatry, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yung-Hsiao Chiang
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei City, Taiwan, ROC; Graduate Institute of Neural Regenerative Medicine, Taipei Medical University, Taipei City, Taiwan, ROC
| | - Barry J Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Jonathan Miller
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Debomoy K Lahiri
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kumar Sambamurti
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Robert E Becker
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA; Aristea Translational Medicine, Park City, UT, USA
| | - Chaim G Pick
- Department of Anatomy & Anthropology, Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
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Sun Y, Fan L, Meng J, Zhang F, Zhang D, Mei Q. Should GLP-1 receptor agonists be used with caution in high risk population for colorectal cancer? Med Hypotheses 2014; 82:255-6. [PMID: 24424394 DOI: 10.1016/j.mehy.2013.11.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/27/2013] [Accepted: 11/26/2013] [Indexed: 11/16/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonists, with few reported side effects, are a kind of very promising anti-diabetes drugs. They are thus being paid high hopes on by both doctors and patients. GLP-1 receptor agonists, however, have not been used in clinic for a long time. Some unknown potential adverse effects may exist. Because GLP-1 receptor agonists enhance β cells proliferation in pancreas via influencing Wnt/β-catenin pathway, a pathway which is associated with tumorigenesis in colon, we then assume that GLP-1 receptor agonists may increase the risk for colorectal cancer.
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Affiliation(s)
- Yang Sun
- Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Lei Fan
- Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Jin Meng
- Department of Pharmacy, No. 309 Hospital of PLA, PR China
| | - Feng Zhang
- Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Dian Zhang
- Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Qibing Mei
- Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China.
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De Tata V. Age-related impairment of pancreatic Beta-cell function: pathophysiological and cellular mechanisms. Front Endocrinol (Lausanne) 2014; 5:138. [PMID: 25232350 PMCID: PMC4153315 DOI: 10.3389/fendo.2014.00138] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/07/2014] [Indexed: 12/13/2022] Open
Abstract
The incidence of type 2 diabetes significantly increases with age. The relevance of this association is dramatically magnified by the concomitant global aging of the population, but the underlying mechanisms remain to be fully elucidated. Here, some recent advances in this field are reviewed at the level of both the pathophysiology of glucose homeostasis and the cellular senescence of pancreatic islets. Overall, recent results highlight the crucial role of beta-cell dysfunction in the age-related impairment of pancreatic endocrine function and delineate the possibility of new original therapeutic interventions.
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Affiliation(s)
- Vincenzo De Tata
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- *Correspondence: Vincenzo De Tata, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma, 55 Scuola Medica, Pisa 56126, Italy e-mail:
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Skibicka KP. The central GLP-1: implications for food and drug reward. Front Neurosci 2013; 7:181. [PMID: 24133407 PMCID: PMC3796262 DOI: 10.3389/fnins.2013.00181] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/20/2013] [Indexed: 12/17/2022] Open
Abstract
Glucagon-like-peptide-1 (GLP-1) and its long acting analogs comprise a novel class of type 2 diabetes (T2D) treatment. What makes them unique among other T2D drugs is their concurrent ability to reduce food intake, a great benefit considering the frequent comorbidity of T2D and obesity. The precise neural site of action underlying this beneficial effect is vigorously researched. In accordance with the classical model of food intake control GLP-1 action on feeding has been primarily ascribed to receptor populations in the hypothalamus and the hindbrain. In contrast to this common view, relevant GLP-1 receptor populations are distributed more widely, with a prominent mesolimbic complement emerging. The physiological relevance of the mesolimbic GLP-1 is suggested by the demonstration that similar anorexic effects can be obtained by independent stimulation of the mesolimbic and hypothalamic GLP-1 receptors (GLP-1R). Results reviewed here support the idea that mesolimbic GLP-1R are sufficient to reduce hunger-driven feeding, the hedonic value of food and food-motivation. In parallel, emerging evidence suggests that the range of action of GLP-1 on reward behavior is not limited to food-derived reward but extends to cocaine, amphetamine, and alcohol reward. The new discoveries concerning GLP-1 action on the mesolimbic reward system significantly extend the potential therapeutic range of this drug target.
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Affiliation(s)
- Karolina P Skibicka
- Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg Gothenburg, Sweden
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Forst T, Pfützner A. Pharmacological profile, efficacy and safety of lixisenatide in type 2 diabetes mellitus. Expert Opin Pharmacother 2013; 14:2281-96. [DOI: 10.1517/14656566.2013.838559] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Zhou J, Keenan MJ, Fernandez-Kim SO, Pistell PJ, Ingram DK, Li B, Raggio AM, Shen L, Zhang H, McCutcheon KL, Tulley RT, Blackman MR, Keller JN, Martin RJ. Dietary resistant starch improves selected brain and behavioral functions in adult and aged rodents. Mol Nutr Food Res 2013; 57:2071-4. [PMID: 23818307 DOI: 10.1002/mnfr.201300135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 11/12/2022]
Abstract
Resistant starch (RS) is a dietary fiber that exerts multiple beneficial effects. The current study explored the effects of dietary RS on selected brain and behavioral functions in adult and aged rodents. Because glucokinase (GK) expression in hypothalamic arcuate nucleus and area postrema of the brainstem is important for brain glucose sensing, GK mRNA was measured by brain nuclei microdissection and PCR. Adult RS-fed rats had a higher GK mRNA than controls in both brain nuclei, an indicator of improved brain glucose sensing. Next, we tested whether dietary RS improve selected behaviors in aged mice. RS-fed aged mice exhibited (i) an increased eating responses to fasting, a behavioral indicator of improvement in aged brain glucose sensing; (ii) a longer latency to fall from an accelerating rotarod, a behavioral indicator of improved motor coordination; and (iii) a higher serum active glucagon-like peptide-1 (GLP-1). Then, GLP-1 receptor null (GLP-1RKO) mice were used to test the role of GLP-1 in brain glucose sensing, and they exhibited impaired eating responses to fasting. We conclude that in rodents (i) dietary RS improves two important indicators of brain function: glucose sensing and motor coordination, and (ii) GLP-1 is important in the optimal feeding response to a fast.
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Affiliation(s)
- June Zhou
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA; Research Service, Veterans Affairs Medical Center, Washington, DC, USA
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Eckerle Mize DL, Salehi M. The place of GLP-1-based therapy in diabetes management: differences between DPP-4 inhibitors and GLP-1 receptor agonists. Curr Diab Rep 2013; 13:307-18. [PMID: 23479200 DOI: 10.1007/s11892-013-0377-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type 2 diabetes is a progressive disease characterized by the need for additional antidiabetic agents overtime to maintain a stable level of glycemic control. The discovery of the glucagon like peptide 1, 1 of the 2 major incretins, was pivotal to the development of novel therapies, which can be used in individuals with type 2 diabetes. Two classes of drugs, GLP-1 receptor agonists and dipeptidyl peptidase inhibitors, provide comparable or superior glycemic effects to previous antidiabetic agents without increasing side effects, such as weight gain and hypoglycemia. Therefore, they represent valuable additions to the current therapeutic options for type 2 diabetes.
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Affiliation(s)
- Dara L Eckerle Mize
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Parkes DG, Mace KF, Trautmann ME. Discovery and development of exenatide: the first antidiabetic agent to leverage the multiple benefits of the incretin hormone, GLP-1. Expert Opin Drug Discov 2012; 8:219-44. [PMID: 23231438 DOI: 10.1517/17460441.2013.741580] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION The GLP-1 receptor agonist exenatide is synthetic exendin-4, a peptide originally isolated from the salivary secretions of the Gila monster. Exenatide was developed as a first-in-class diabetes therapy, with immediate- and extended-release formulations. In preclinical diabetes models, exenatide enhanced glucose-dependent insulin secretion, suppressed inappropriately elevated glucagon secretion, slowed gastric emptying, reduced body weight, enhanced satiety, and preserved pancreatic β-cell function. In clinical trials, both exenatide formulations reduced hyperglycemia in patients with type 2 diabetes mellitus (T2DM) and were associated with weight loss. AREAS COVERED This article reviews the development of exenatide from its discovery and preclinical investigations, to the elucidation of its pharmacological mechanisms of action in mammalian systems. The article also presents the pharmacokinetic profiling and toxicology studies of exenatide, as well as its validation in clinical trials. EXPERT OPINION GLP-1 receptor agonists represent a new paradigm for the treatment of patients with T2DM. By leveraging incretin physiology, a natural regulatory system that coordinates oral nutrient intake with mechanisms of metabolic control, these agents address multiple core defects in the pathophysiology of T2DM. Studies have identified unique benefits including improvements in glycemic control and weight, and the potential for beneficial effects on the cardiometabolic system without the increased risk of hypoglycemia associated with insulin therapy. Peptide hormone therapeutics can offer significant advantages over small molecule drug targets when it comes to specificity, potency, and more predictable side effects. As exemplified by exenatide, injectable peptides can be important drugs for the treatment of chronic diseases, such as T2DM.
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Affiliation(s)
- David G Parkes
- Amylin Pharmaceuticals, Inc., 9360 Towne Centre Drive, San Diego, CA 92121, USA.
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Yang M, Zhang L, Wang C, Liu H, Boden G, Yang G, Li L. Liraglutide increases FGF-21 activity and insulin sensitivity in high fat diet and adiponectin knockdown induced insulin resistance. PLoS One 2012; 7:e48392. [PMID: 23152772 PMCID: PMC3495944 DOI: 10.1371/journal.pone.0048392] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 09/25/2012] [Indexed: 11/18/2022] Open
Abstract
Background Liraglutide is a glucagon-like peptide-1 analogue that stimulates insulin secretion and improves β-cell function. However, it is not clear whether liraglutide achieves its glucose lowering effect only by its known effects or whether other as yet unknown mechanisms are involved. The aim of this study was to examine the effects of liraglutide on Fibroblast growth factor-21 (FGF-21) activity in High-fat diet (HFD) fed ApoE−/− mice with adiponectin (Acrp30) knockdown. Method HFD-fed ApoE−/− mice were treated with adenovirus vectors expressing shAcrp30 to produce insulin resistance. Hyperinsulinemic-euglycemic clamp studies were performed to evaluate insulin sensitivity of the mouse model. QRT-PCR and Western blot were used to measure the mRNA and protein expression of the target genes. Results The combination of HFD, ApoE deficiency, and hypoadiponectinemia resulted in an additive effect on insulin resistance. FGF-21 mRNA expressions in both liver and adipose tissues were significantly increased while FGF-21 receptor 1 (FGFR-1) and β-Klotho mRNA levels in adipose tissue, as well as FGFR-1-3 and β-Klotho mRNA levels in liver were significantly decreased in this model. Liraglutide treatment markedly improved insulin resistance and increased FGF-21 expression in liver and FGFR-3 in adipose tissue, restored β-Klotho mRNA expression in adipose tissue as well as FGFR-1-3, β-Klotho levels and phosphorylation of FGFR1 up to the levels observed in control mice in liver. Liraglutide treatment also further increased FGF-21 proteins in liver and plasma. In addition, as shown by hyperinsulinemic-euglycemic clamp, liraglutide treatment also markedly improved glucose metabolism and insulin sensitivity in these animals. Conclusion These findings demonstrate an additive effect of HFD, ApoE deficiency, and adiponectin knockdown on insulin resistance and unveil that the regulation of glucose metabolism and insulin sensitivity by liraglutide may be partly mediated via increased FGF-21 and its receptors action.
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Affiliation(s)
- Mengliu Yang
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Lili Zhang
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Chong Wang
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Hua Liu
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Guenther Boden
- The Division of Endocrinology/Diabetes/Metabolism and the Clinical Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Gangyi Yang
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
- * E-mail: (LL); (GY)
| | - Ling Li
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
- * E-mail: (LL); (GY)
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Abstract
Unfortunately, the only approved medical treatment for type 1 diabetes mellitus (DM) is insulin, despite the fact that tight control cannot be reached without some serious side effects such as hypoglycemia and weight gain. More and more importance is now shifted towards developing new drugs that can reach a better glycemic control with lesser side effects. Some of these promising drugs are the glucagon-like peptides 1 (GLP-1) and their agonists, which have been FDA approved for the treatment of type 2 DM. The purpose of this article is to review all of the relevant literature on the potential role of GLP-1 in the treatment of type 1 DM. The major source of data acquisition included Medline search strategies, using the words "type 1 diabetes mellitus" and "GLP-1." Articles published in the last 20 years were screened. GLP-1 increases insulin secretion in humans with existing beta cells; it also decreases glucagon secretion, and blunts appetite. Of note, new animal studies demonstrate a role in beta cell-proliferation and decreased apoptosis. Because of all the effects mentioned above, GLP-1 seems to be a promising drug for type 1 DM treatment, but more studies are still needed before solid conclusions can be drawn.
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Affiliation(s)
- Claire M Issa
- Department of Internal Medicine, Division of Endocrinology and Metabolism, American University of Beirut-Medical Center, New York, NY 10017, USA
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Wang H, Jiang Z, Li A, Gao Y. Characterization of insulin-producing cells derived from PDX-1-transfected neural stem cells. Mol Med Rep 2012; 6:1428-32. [PMID: 23008108 DOI: 10.3892/mmr.2012.1089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 08/20/2012] [Indexed: 11/06/2022] Open
Abstract
Islet cell transplantation is a promising treatment strategy for type-1 diabetes. However, functional islet cells are hard to obtain for transplantation and are in short supply. Directing the differentiation of stem cells into insulin‑producing cells, which serve as islet cells, would overcome this shortage. Bone marrow contains hematopoietic stem cells and mesenchymal stem cells. The present study used bone marrow cells isolated from rats and neural stem cells (NSCs) that were derived from bone marrow cells in culture. Strong nestin staining was detected in NSCs, but not in bone marrow stromal cells (BMSCs). In vitro transfection of the pancreatic duodenal homeobox-1 (PDX-1) gene into NSCs generated insulin‑producing cells. Reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) analysis confirmed that PDX-1-transfected NSCs expressed insulin mRNA and released insulin protein. However, insulin release from PDX-1-transfected NSCs did not respond to the challenge of glucose and glucagon-like peptide-1. These results support the use of bone marrow-derived NSCs as a renewable source of insulin-producing cells for autologous transplantation to treat type-1 diabetes.
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Affiliation(s)
- Hailan Wang
- Department of Endocrinology, Shenzhen Longgang Central Hospital, Shenzhen 518000, P.R. China
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Delgado TC, Barosa C, Nunes PM, Scott DK, O'Doherty RM, Cerdán S, Geraldes CFGC, Jones JG. Effect of cyclosporine A on hepatic carbohydrate metabolism and hepatic gene expression in rat. Expert Opin Drug Metab Toxicol 2012; 8:1223-30. [DOI: 10.1517/17425255.2012.709500] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Akarte AS, Srinivasan BP, Gandhi S. Vildagliptin selectively ameliorates GLP-1, GLUT4, SREBP-1c mRNA levels and stimulates β-cell proliferation resulting in improved glucose homeostasis in rats with streptozotocin-induced diabetes. J Diabetes Complications 2012; 26:266-74. [PMID: 22626875 DOI: 10.1016/j.jdiacomp.2012.03.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/29/2012] [Accepted: 03/13/2012] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Inhibitors of dipeptidyl peptidase-4 (DPP-4), a key regulator of the actions of incretin hormones, exert antihyperglycemic effects in type 2 diabetic patients. A major unanswered question concerns the potential ability of DPP-4 inhibition to have beneficial disease-modifying effects, specifically to attenuate loss of pancreatic β-cell mass and function due to oxidative stress induced inflammation. Here, we investigated the effects of a potent and selective DPP-4 inhibitor vildagliptin on glycemic control, pancreatic β-cell mass and function, genes and proteins expressions, tumor necrosis factor-alpha, and nitric oxide in an n2-STZ diabetic model of rat with defects in insulin sensitivity and secretion. METHOD To induce NIDDM, STZ (sigma chemicals, USA) (90 mg/kg) was administered i.p. to a group of 2 days old pups. Another group of pups received only saline. The pups were weaned for 21 days, and 6 weeks after the injection of STZ, the animals were checked for fasting glucose level (FPG) ≥160 mg/dl were considered as diabetic. RESULTS Significant and dose-dependent correction of postprandial and fasting hyperglycemia was observed in diabetic rats following 8 weeks of chronic therapy. Treatment with vildagliptin showed increase in the number of insulin-positive β-cells in islets and improved the expressions of genes and proteins are responsible for insulin secretions. In addition, treatment of rats with vildagliptin significantly increased insulin content; and decreased the nitric oxide and TNF-alpha concentration. CONCLUSION These findings suggest that DPP-4 inhibitors may offer long-lasting efficacy in the treatment of diabetes mellitus by modifying the courses of the disease.
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Affiliation(s)
- Atul Sureshrao Akarte
- Delhi Institute of Pharmaceutical Sciences and Research, Pushp Vihar, Sector-3, MB Road, New Delhi -110017, India.
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Mfopou JK, Baeyens L, Bouwens L. Hedgehog signals inhibit postnatal beta cell neogenesis from adult rat exocrine pancreas in vitro. Diabetologia 2012; 55:1024-34. [PMID: 22237687 DOI: 10.1007/s00125-011-2434-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 12/05/2011] [Indexed: 10/14/2022]
Abstract
AIMS/HYPOTHESIS Transdifferentiation of pancreatic exocrine cells into insulin-producing beta cells may represent an important alternative to islets required for diabetes cell therapy. Rat pancreatic acinar cells are known to transdifferentiate into functional beta cells, with recapitulation of several pancreas developmental features. Considering the inhibitory functions of hedgehog signalling in early and mid-stage pancreatic development, we questioned whether it also operates in transdifferentiating acinar cells and whether its modulation would influence postnatal beta cell neogenesis in vitro. METHODS Rat exocrine cells were precultured in suspension for 4 days and then incubated with EGF and leukaemia inhibitory factor (LIF) for 72 h. The hedgehog signalling pathway was modulated during this, and its effects analysed by RT-PCR, immunocytochemistry and western blot. RESULTS Our data indicate induction of Dhh and Ihh, but not Shh, expression during acinar cell culture, resulting in activation of hedgehog targets (Ptc1, Gli1). Exposure of the metaplastic cells to EGF and LIF induced beta cell differentiation without affecting endogenous hedgehog activity. Whereas blocking endogenous hedgehog only slightly increased beta cell neogenesis, exposure to embryoid body-conditioned medium activated hedgehog signalling as well as other pathways such as Notch, resulting in severe blockade of beta cell neogenesis. Interestingly, this effect was partially rescued by treatment with the hedgehog inhibitor, 3-keto-N-(aminoethyl-aminocaproyl-dihydrocinnamoyl)-cyclopamine (KAAD-cyclopamine), alone. CONCLUSIONS/INTERPRETATION We report here Dhh/Ihh-dependent activation of hedgehog targets during pancreatic exocrine cell metaplasia in vitro and a persistent inhibitory function of hedgehog signalling in a model of postnatal beta cell differentiation.
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Affiliation(s)
- J K Mfopou
- Diabetes Research Center, Vrije Universiteit Brussel, Laarbeeklaan, Brussels, Belgium
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Knudsen LB, Hastrup S, Underwood CR, Wulff BS, Fleckner J. Functional importance of GLP-1 receptor species and expression levels in cell lines. ACTA ACUST UNITED AC 2012; 175:21-9. [DOI: 10.1016/j.regpep.2011.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/18/2011] [Accepted: 12/22/2011] [Indexed: 12/20/2022]
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Akarte AS, Srinivasan B, Gandhi S. A novel long acting DPP-IV inhibitor PKF-275-055 stimulates β-cell proliferation resulting in improved glucose homeostasis in diabetic rats. Biochem Pharmacol 2012; 83:241-52. [DOI: 10.1016/j.bcp.2011.10.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/04/2011] [Accepted: 10/04/2011] [Indexed: 11/27/2022]
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Zhou J, Keenan MJ, Keller J, Fernandez-Kim SO, Pistell PJ, Tulley RT, Raggio AM, Shen L, Zhang H, Martin RJ, Blackman MR. Tolerance, fermentation, and cytokine expression in healthy aged male C57BL/6J mice fed resistant starch. Mol Nutr Food Res 2011; 56:515-8. [PMID: 22174009 DOI: 10.1002/mnfr.201100521] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 09/19/2011] [Accepted: 10/07/2011] [Indexed: 12/17/2022]
Abstract
Health benefits of resistant starch (RS), a dietary fermentable fiber, have been well documented in young, but not in old populations. As the essential step of more comprehensive evaluations of RS on healthy aging, we examined the effects of dietary RS on tolerance, colonic fermentation, and cytokine expression in aged mice. Healthy older (18-20 months) C57BL/6J male mice were fed control, 18% RS, or 36% RS diets for 10 weeks. Body weight gain, body composition, and fat pad weights did not differ among the three groups after 10 weeks, indicating good tolerance of the RS diet. Fermentation indicators (cecum weights, and cecal proglucagon and PYY mRNA expression) were enhanced in an RS dose-dependent manner (p<0.01). Serum concentrations of soluble cytokine receptors (sTNF-Rb, sIL-4R, sIL-2Rα, sVEGFR1, and sRAGE) and TNFα expression (gene and protein) in visceral fat did not differ significantly among groups. Adiponectin protein concentrations, but not gene expression, were greater in epididymal fat of the 36% RS versus control groups (p<0.05). As a conclusion in aged mice, dietary RS is well tolerated, fermented in the colon, and stimulates colonic expression of proglucagon and PYY mRNA, and adiponectin protein in visceral fat.
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Affiliation(s)
- June Zhou
- Pennington Biomedical Research Center, Louisiana State University System, Louisiana, USA.
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Aston-Mourney K, Hull RL, Zraika S, Udayasankar J, Subramanian SL, Kahn SE. Exendin-4 increases islet amyloid deposition but offsets the resultant beta cell toxicity in human islet amyloid polypeptide transgenic mouse islets. Diabetologia 2011; 54:1756-65. [PMID: 21484213 PMCID: PMC3220951 DOI: 10.1007/s00125-011-2143-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 03/17/2011] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS In type 2 diabetes, aggregation of islet amyloid polypeptide (IAPP) into amyloid is associated with beta cell loss. As IAPP is co-secreted with insulin, we hypothesised that IAPP secretion is necessary for amyloid formation and that treatments that increase insulin (and IAPP) secretion would thereby increase amyloid formation and toxicity. We also hypothesised that the unique properties of the glucagon-like peptide-1 (GLP-1) receptor agonist exendin-4 to maintain or increase beta cell mass would offset the amyloid-induced toxicity. METHODS Islets from amyloid-forming human IAPP transgenic and control non-transgenic mice were cultured for 48 h in 16.7 mmol/l glucose alone (control) or with exendin-4, potassium chloride (KCl), diazoxide or somatostatin. Human IAPP and insulin release, amyloid deposition, beta cell area/islet area, apoptosis and AKT phosphorylation levels were determined. RESULTS In control human IAPP transgenic islets, amyloid formation was associated with increased beta cell apoptosis and beta cell loss. Increasing human IAPP release with exendin-4 or KCl increased amyloid deposition. However, while KCl further increased beta cell apoptosis and beta cell loss, exendin-4 did not. Conversely, decreasing human IAPP release with diazoxide or somatostatin limited amyloid formation and its toxic effects. Treatment with exendin-4 was associated with an increase in AKT phosphorylation compared with control and KCl-treated islets. CONCLUSIONS/INTERPRETATION IAPP release is necessary for islet amyloid formation and its toxic effects. Thus, use of insulin secretagogues to treat type 2 diabetes may result in increased islet amyloidogenesis and beta cell death. However, the AKT-associated anti-apoptotic effects of GLP-1 receptor agonists such as exendin-4 may limit the toxic effects of increased islet amyloid.
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Affiliation(s)
- K Aston-Mourney
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System (151), 1660 South Columbian Way, Seattle, WA 98108, USA.
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Exendin-4 improves blood glucose control in both young and aging normal non-diabetic mice, possible contribution of beta cell independent effects. PLoS One 2011; 6:e20443. [PMID: 21655268 PMCID: PMC3105063 DOI: 10.1371/journal.pone.0020443] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 05/03/2011] [Indexed: 12/25/2022] Open
Abstract
Aims Type 2 diabetes is highly prevalent in the elderly population. Glucagon like Peptide-1 mimetic such as exendin-4 augments post-prandial insulin secretion. However, the potential influence of aging on the therapeutic effects of this peptide has not been well studied. In this study, we examined the glucose regulatory effects of exendin-4 in mice with different ages. Methods We treated 3-month and 20 to 22-month old C57/DBA mice with 10 nM/kg exendin-4 for 10 days with measurements of blood glucose and body weight. We performed OGTT and ITT to evaluate the glucose response and insulin sensitivity. Islet morphology and beta cell mass were measured by immuno-staining and beta cell proliferation was evaluated by BrdU incorporation and PCNA staining. Real-time PCR and western blot were used to measure protein changes in the liver tissue after exendin-4 treatment. Results Exendin-4 treatment improved glycemic control in both 3-month and 20 to 22-month old mice. In both groups of mice, the blood glucose lowering effect was independent of beta cell function as indicated by unchanged beta cell proliferation, insulin secretion or beta cell mass. Moreover, we found that exendin-4 treatment increased hepatic AKT and FOXO1 phosphorylation and inhibited glucose-6-phosphotase (G6P) and Phosphoenolpyruvate carboxykinase (PEPCK) expression in young mice, but this effect was attenuated in aging mice while the insulin sensitivity showed no change in the young group but significantly improved in aging mice. Conclusion Based on these data, we conclude that the glucose lowering effect of exendin-4 in normal non-diabetic mice was not blunted by aging. We further showed that although there was slight difference in the glucose modulating mechanism of exendin-4 therapy in young and aged mice, the improved glucose control seemed uncorrelated with increased beta cell mass or insulin secretion.
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Shimoda M, Kanda Y, Hamamoto S, Tawaramoto K, Hashiramoto M, Matsuki M, Kaku K. The human glucagon-like peptide-1 analogue liraglutide preserves pancreatic beta cells via regulation of cell kinetics and suppression of oxidative and endoplasmic reticulum stress in a mouse model of diabetes. Diabetologia 2011; 54:1098-108. [PMID: 21340625 PMCID: PMC3071950 DOI: 10.1007/s00125-011-2069-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 12/22/2010] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS We investigated the molecular mechanism by which the human glucagon-like peptide-1 analogue liraglutide preserves pancreatic beta cells in diabetic db/db mice. METHODS Male db/db and m/m mice aged 10 weeks received liraglutide or vehicle for 2 days or 2 weeks. In addition to morphological and biochemical analysis of pancreatic islets, gene expression profiles in the islet core area were investigated by laser capture microdissection and real-time RT-PCR. RESULTS Liraglutide treatment for 2 weeks improved metabolic variables and insulin sensitivity in db/db mice. Liraglutide also increased glucose-stimulated insulin secretion (GSIS) and islet insulin content in both mouse strains and reduced triacylglycerol content in db/db mice. Expression of genes involved in cell differentiation and proliferation in both mouse strains was regulated by liraglutide, which, in db/db mice, downregulated genes involved in pro-apoptosis, endoplasmic reticulum (ER) stress and lipid synthesis, and upregulated genes related to anti-apoptosis and anti-oxidative stress. In the 2 day experiment, liraglutide slightly improved metabolic variables in db/db mice, but GSIS, insulin and triacylglycerol content were not affected. In db/db mice, liraglutide increased gene expression associated with cell differentiation, proliferation and anti-apoptosis, and suppressed gene expression involved in pro-apoptosis; it had no effect on genes related to oxidative stress or ER stress. Morphometric results for cell proliferation, cell apoptosis and oxidative stress in db/db mice islets were consistent with the results of the gene expression analysis. CONCLUSIONS/INTERPRETATION Liraglutide increases beta cell mass not only by directly regulating cell kinetics, but also by suppressing oxidative and ER stress, secondary to amelioration of glucolipotoxicity.
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Affiliation(s)
- M. Shimoda
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - Y. Kanda
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - S. Hamamoto
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - K. Tawaramoto
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - M. Hashiramoto
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - M. Matsuki
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
| | - K. Kaku
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192 Japan
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Abstract
The complex pathological mechanisms responsible for development of type 2 diabetes are not fully addressed by conventional drugs, which are also associated with inconvenient side effects such as weight gain or hypoglycemia. Two types of incretin-based therapies are now in use: incretin mimetics (glucagon-like peptide-1 [GLP-1] receptor agonists that bind specific receptors and mimic the action of natural GLP-1) and incretin enhancers (inhibitors of the enzyme that degrade the incretin hormones and thus prolong their activity). Both offer important advantages over previous agents. In addition to the proven glucose-lowering efficacy, they promote weight loss (or are weight neutral) by slowing gastric emptying and inducing satiety, inhibit glucagon secretion with maintenance of counterregulatory mechanisms, and exhibit cardiovascular benefits, while having a low risk profile. Importantly, short-term studies have shown that incretins/incretin-based therapies protect β-cells (by enhancing cell proliferation and differentiation and inhibiting apoptosis) and stimulate their function (by recruiting β-cells to the secretory process and increasing insulin biosynthesis/secretion). These therapies have the opportunity to interfere with the disease progression if used as an early intervention, when enough β-cell mass/function can still be preserved or restored.
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Affiliation(s)
- Simona Cernea
- Diabetes, Nutrition and Metabolic Diseases Outpatient Unit, Emergency County Clinical Hospital, Târgu Mureş, Romania.
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