1
|
Abubakar M, Nama L, Ansari MA, Ansari MM, Bhardwaj S, Daksh R, Syamala KLV, Jamadade MS, Chhabra V, Kumar D, Kumar N. GLP-1/GIP Agonist as an Intriguing and Ultimate Remedy for Combating Alzheimer's Disease through its Supporting DPP4 Inhibitors: A Review. Curr Top Med Chem 2024; 24:1635-1664. [PMID: 38803170 DOI: 10.2174/0115680266293416240515075450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/14/2024] [Accepted: 04/22/2024] [Indexed: 05/29/2024]
Abstract
BACKGROUND Alzheimer's disease (AD) is a widespread neurological illness in the elderly, which impacted about 50 million people globally in 2020. Type 2 diabetes has been identified as a risk factor. Insulin and incretins are substances that have various impacts on neurodegenerative processes. Preclinical research has shown that GLP-1 receptor agonists decrease neuroinflammation, tau phosphorylation, amyloid deposition, synaptic function, and memory formation. Phase 2 and 3 studies are now occurring in Alzheimer's disease populations. In this article, we present a detailed assessment of the therapeutic potential of GLP-1 analogues and DPP4 inhibitors in Alzheimer's disease. AIM This study aimed to gain insight into how GLP-1 analogues and associated antagonists of DPP4 safeguard against AD. METHODS This study uses terms from search engines, such as Scopus, PubMed, and Google Scholar, to explore the role, function, and treatment options of the GLP-1 analogue for AD. RESULTS The review suggested that GLP-1 analogues may be useful for treating AD because they have been linked to anti-inflammatory, neurotrophic, and neuroprotective characteristics. Throughout this review, we discuss the underlying causes of AD and how GLP signaling functions. CONCLUSION With a focus on AD, the molecular and pharmacological effects of a few GLP-1/GIP analogs, both synthetic and natural, as well as DPP4 inhibitors, have been mentioned, which are in the preclinical and clinical studies. This has been demonstrated to improve cognitive function in Alzheimer's patients.
Collapse
Affiliation(s)
- Mohammad Abubakar
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Lokesh Nama
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Mohammad Arif Ansari
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Mohammad Mazharuddin Ansari
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Shivani Bhardwaj
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Rajni Daksh
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Katta Leela Venkata Syamala
- Department of Regulatory and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Mohini Santosh Jamadade
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Vishal Chhabra
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| | - Dileep Kumar
- Poona College of Pharmacy, Bharati Vidyapeeth (Deemed to be) University, Pune, Maharashtra, 411038, India
- Department of Entomology, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - Nitesh Kumar
- Department of Pharmacology and Toxicology, National Institution of Pharmaceutical Education and Research, Hajipur, Vaishali, 844102, Bihar, India
| |
Collapse
|
2
|
Lei M, Guo X, Yao Y, Shu T, Ren Z, Yang X, Ouyang C, Chen Q, Liu C, Liu X. Trelagliptin relieved cognitive impairment of diabetes mellitus rats: Involvement of PI3K/Akt/GSK-3β and inflammation pathway. Exp Gerontol 2023; 182:112307. [PMID: 37804920 DOI: 10.1016/j.exger.2023.112307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 09/25/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
Cognitive impairment frequently coexists with diabetes. Trelagliptin is a once-weekly taking selective dipeptidyl peptidase-4 (DPP-4) inhibitor and a long-term effective hypoglycemic medicine; nonetheless, its effects for the treatment of diabetes-related cognitive impairment have only sometimes been explored. In this study, a DM model was built using streptozotocin (STZ) and a high-fat diet (HFD). The morris water maze test on DM rats revealed a considerably reduced capacity for spatial learning and memory, but trelagliptin was able to restore function. Trelagliptin could lower the mRNA expression of inflammatory factors such IL-1β, TNF-α, and IL-6 in DM rats. It could also reduce the ratio of p-IKKα/IKKα, and the immunofluorescence result of NF-κB also demonstrated a drop. Trelagliptin partially restored dendritic spines and prevented the loss or shrinkage of neurons, respectively, according to the results of Nissl's staining and golgi staining. Furthermore, PI3K/Akt/GSK-3β has been activated, and synaptic plasticity has been modified during this process. In conclusion, trelagliptin improved the cognitive lesion in DM rats by suppressing the activation of the inflammatory route and by activating the PI3K/Akt/GSK-3β pathway at the same time, as well as interacting with the pathways that protect neurons, which still need further research.
Collapse
Affiliation(s)
- Min Lei
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Xiying Guo
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Yue Yao
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China; Pharmacy College, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Ting Shu
- Pharmacy College, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Zhanhong Ren
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Xiaosong Yang
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Changhan Ouyang
- Pharmacy College, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Qingjie Chen
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China.
| | - Chao Liu
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China.
| | - Xiufen Liu
- Hubei key laboratory of diabetes and angiopathy, Medical research institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China.
| |
Collapse
|
3
|
Guo X, Lei M, Zhao J, Wu M, Ren Z, Yang X, Ouyang C, Liu X, Liu C, Chen Q. Tirzepatide ameliorates spatial learning and memory impairment through modulation of aberrant insulin resistance and inflammation response in diabetic rats. Front Pharmacol 2023; 14:1146960. [PMID: 37701028 PMCID: PMC10493299 DOI: 10.3389/fphar.2023.1146960] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023] Open
Abstract
Background: One of the typical symptoms of diabetes mellitus patients was memory impairment, which was followed by gradual cognitive deterioration and for which there is no efficient treatment. The anti-diabetic incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) were demonstrated to have highly neuroprotective benefits in animal models of AD. We wanted to find out how the GLP-1/GIP dual agonist tirzepatide affected diabetes's impairment of spatial learning memory. Methods: High fat diet and streptozotocin injection-induced diabetic rats were injected intraperitoneally with Tirzepatide (1.35 mg/kg) once a week. The protective effects were assessed using the Morris water maze test, immunofluorescence, and Western blot analysis. Golgi staining was adopted for quantified dendritic spines. Results: Tirzepatide significantly improved impaired glucose tolerance, fasting blood glucose level, and insulin level in diabetic rats. Then, tirzepatide dramatically alleviated spatial learning and memory impairment, inhibited Aβ accumulation, prevented structural damage, boosted the synthesis of synaptic proteins and increased dendritic spines formation in diabetic hippocampus. Furthermore, some aberrant changes in signal molecules concerning inflammation signaling pathways were normalized after tirzepatide treatment in diabetic rats. Finally, PI3K/Akt/GSK3β signaling pathway was restored by tirzepatide. Conclusion: Tirzepatide obviously exerts a protective effect against spatial learning and memory impairment, potentially through regulating abnormal insulin resistance and inflammatory responses.
Collapse
Affiliation(s)
- Xiying Guo
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Min Lei
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Jiangyan Zhao
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Min Wu
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Zhanhong Ren
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Xiaosong Yang
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Changhan Ouyang
- Pharmacy College, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Xiufen Liu
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Chao Liu
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| | - Qingjie Chen
- Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Medical Research Institute, Hubei University of Science and Technology, Xianning, China
| |
Collapse
|
4
|
Abdelhafiz AH. Effects of hypoglycaemic therapy on frailty: a multi-dimensional perspective. Expert Rev Endocrinol Metab 2023; 18:53-65. [PMID: 36650694 DOI: 10.1080/17446651.2023.2168644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
INTRODUCTION The prevalence of diabetes is increasing in older people. With increasing age, frailty emerges as a new complication leading to disability. Frailty does not only include physical dysfunction but also involves negative impact on cognition and mood. Triad of impairments (TOI) is a new concept that includes physical frailty, dementia and depression to reflect the wider spectrum of frailty. AREAS COVERED Little is known about effects of hypoglycaemic agents on frailty syndrome. A literature search was performed on studies, which reported effects of hypoglycaemic agents on the component of the TOI. EXPERT OPINION It appears that most hypoglycaemic agents have some effects on frailty, although the results of clinical studies are inconsistent. Metformin seems to have a consistent and a positive effect on physical frailty. Its effects on cognitive function, however, are inconclusive but tend to be positive. Metformin appeared to improve depressive symptoms. Other agents such as incretins, thiazolidinediones, and sodium glucose transporter-2 inhibitors have some positive effects on cognition and depression. Sulfonylureas, glinides, or insulin have either negative or neutral effects on TOI components. The negative effects of insulin could be partially explained by the negative psychological factors and the frequent episodes of hypoglycemia associated with such therapy.
Collapse
Affiliation(s)
- Ahmed H Abdelhafiz
- Department of Geriatric Medicine, Rotherham General Hospital, Moorgate Road, Rotherham, UK
| |
Collapse
|
5
|
Du H, Meng X, Yao Y, Xu J. The mechanism and efficacy of GLP-1 receptor agonists in the treatment of Alzheimer's disease. Front Endocrinol (Lausanne) 2022; 13:1033479. [PMID: 36465634 PMCID: PMC9714676 DOI: 10.3389/fendo.2022.1033479] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/27/2022] [Indexed: 11/18/2022] Open
Abstract
Since type 2 diabetes mellitus (T2DM) is a risk factor for Alzheimer's disease (AD) and both have the same pathogenesis (e.g., insulin resistance), drugs used to treat T2DM have been gradually found to reduce the progression of AD in AD models. Of these drugs, glucagon-like peptide 1 receptor (GLP-1R) agonists are more effective and have fewer side effects. GLP-1R agonists have reducing neuroinflammation and oxidative stress, neurotrophic effects, decreasing Aβ deposition and tau hyperphosphorylation in AD models, which may be a potential drug for the treatment of AD. However, this needs to be verified by further clinical trials. This study aims to summarize the current information on the mechanisms and effects of GLP-1R agonists in AD.
Collapse
Affiliation(s)
- Haiyang Du
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xiaoyu Meng
- Division of Endocrinology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Branch of National Clinical Research Center for Metabolic Diseases, Hubei, China
| | - Yu Yao
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jun Xu
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
- *Correspondence: Jun Xu,
| |
Collapse
|
6
|
Zhang X, Liu K, Shi M, Xie L, Deng M, Chen H, Li X. Therapeutic potential of catalpol and geniposide in Alzheimer's and Parkinson's diseases: A snapshot of their underlying mechanisms. Brain Res Bull 2021; 174:281-295. [PMID: 34216649 DOI: 10.1016/j.brainresbull.2021.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 06/09/2021] [Accepted: 06/29/2021] [Indexed: 01/28/2023]
Abstract
Rehmannia glutinosa, the fresh or dried root of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & Mey., and Gardenia, the fruit of Gardenia jasminoides Ellis from Rubiaceae, both are famous traditional Chinese medicines that have been traditionally used in China. Catalpol and geniposide, as two kinds of iridoid glycosides with high activities, are the main bioactive components in Rehmannia glutinosa and Gardenia jasminoides Ellis, respectively. Over the past few decades, catalpol and geniposide have been widely studied for their therapeutic effects. The preclinical experiments demonstrated that they possessed significant neuroprotective activities against Alzheimer's disease, Parkinson's disease, stroke, and depression, etc. In this paper, the pharmacological effects and mechanisms of catalpol and geniposide on Alzheimer's disease and Parkinson's disease from 2005 to now were systematically summarized and comprehensively analyzed. At the same time, the pharmacokinetic characteristics of the analyzed compounds were also described, hoping to provide some enlightenment for the design, research, and development of iridoid glycosides.
Collapse
Affiliation(s)
- Xumin Zhang
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Kai Liu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Mingyi Shi
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Long Xie
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Mao Deng
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Huijuan Chen
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Xiaofang Li
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| |
Collapse
|
7
|
Kim SH, Park TS, Jin HY. Metformin Preserves Peripheral Nerve Damage with Comparable Effects to Alpha Lipoic Acid in Streptozotocin/High-Fat Diet Induced Diabetic Rats. Diabetes Metab J 2020; 44:842-853. [PMID: 32602278 PMCID: PMC7801759 DOI: 10.4093/dmj.2019.0190] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 11/28/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Metformin is widely marketed medication for the treatment of diabetes, but its pharmacological effect on diabetic peripheral neuropathy remains unclear. In this study, the effect of metformin on peripheral nerves in diabetic rats was investigated using diverse neuronal parameters of nerve fibers. METHODS Rats were assigned to one of four groups (n=7 to 10 per group): normal, diabetes mellitus (DM), DM+metformin (100 mg/kg), and DM+alpha lipoic acid (ALA, 100 mg/kg). DM was induced by streptozotocin/high-fat diet (STZ/HFD). After 12 weeks, the sensory thresholds to mechanical and heat stimuli were assessed. Repeated sensory tests, immunofluorescence microscopic comparison of peripheral nerves, and biochemical blood analysis were performed after 24 weeks. RESULTS Both DM+metformin and DM+ALA groups showed similar trends to diverse sensory tests at 24 weeks compared to DM group although the degree of change were different according to the stimulated senses. There was no significant difference in the comparison of the intraepidermal nerve fiber density (IENFD) of peripheral nerves between the DM+metformin and DM+ALA groups (11.83±0.07 fibers/mm vs. 12.37±1.82 fibers/mm, respectively). Both groups showed preserved IENFD significantly compared with DM group (8.46±1.98 fibers/mm, P<0.05). Sciatic nerve morphology of the experimental animals showed a similar trend to the IENFD, with respect to axonal diameter, myelin sheath thickness, and myelinated fiber diameter. CONCLUSION Metformin has beneficial pharmacological effects on the preservation of peripheral nerves in diabetic rats and its effects are comparable to those of ALA.
Collapse
Affiliation(s)
- Sun Hee Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea
| | - Tae Sun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea
| | - Heung Yong Jin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea
| |
Collapse
|
8
|
Yaribeygi H, Rashidy-Pour A, Atkin SL, Jamialahmadi T, Sahebkar A. GLP-1 mimetics and cognition. Life Sci 2020; 264:118645. [PMID: 33121988 DOI: 10.1016/j.lfs.2020.118645] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonists are a class of antidiabetic drugs that improve the glycaemia via several molecular pathways. Recent evidence suggest that they also have additional effects modulating pathophysiologic pathways included in cognitive disorders. Since some forms of cognitive dysfunction such as Alzheimer's disease are more common among diabetic patients than in the normal population, antidiabetic drugs that have neuroprotective effects affording protection for cognitive disorders would be of benefit. Therefore, we reviewed the pharmacologic effects of GLP-1 analogues and found that they may have the additional benefit of improving cognitive performance via at least eight molecular mechanisms.
Collapse
Affiliation(s)
- Habib Yaribeygi
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran
| | - Ali Rashidy-Pour
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran.
| | | | - Tannaz Jamialahmadi
- Department of Food Science and Technology, Quchan Branch, Islamic Azad University, Quchan, Iran; Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Halal Research Center of IRI, FDA, Tehran, Iran; Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.
| |
Collapse
|
9
|
Exenatide alleviates mitochondrial dysfunction and cognitive impairment in the 5×FAD mouse model of Alzheimer’s disease. Behav Brain Res 2019; 370:111932. [DOI: 10.1016/j.bbr.2019.111932] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/21/2019] [Accepted: 04/30/2019] [Indexed: 01/14/2023]
|
10
|
Borzì AM, Condorelli G, Biondi A, Basile F, Vicari ESD, Buscemi C, Luca S, Vacante M. Effects of vildagliptin, a DPP-4 inhibitor, in elderly diabetic patients with mild cognitive impairment. Arch Gerontol Geriatr 2019; 84:103896. [PMID: 31204117 DOI: 10.1016/j.archger.2019.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 06/02/2019] [Accepted: 06/02/2019] [Indexed: 01/06/2023]
Abstract
INTRODUCTION There is an unclear association between type 2 diabetes and mild cognitive impairment in the elderly. Both diseases are more prevalent in the older adults compared to the younger counterpart. Some anti-diabetic drugs seem to influence positively the evolution of mild cognitive impairment. This retrospective study investigated the effect of vildagliptin, an inhibitor of the enzyme dipeptidyl peptidase-4 (DPP-4), on the cognitive functioning of elderly diabetic patients with mild cognitive impairment (MCI) documented at mini mental state examination (MMSE). METHODS We included 60 diabetic elderly people which were divided in 2 groups: Group A, 30 patients with HbA1c (glycated hemoglobin) ≤7.5% and treated with metformin, and Group B, 30 patients with HbA1c >7.5%, and treated with metformin plus vildagliptin. We collected data on MMSE, fasting plasma glucose (FPG) and HbA1c at baseline and after 180 ± 10 days from the beginning of treatment. RESULTS The two groups exhibited significantly different values in FPG (P < 0.05) and HbA1c (P < 0.01) at baseline, and in MMSE score (P < 0.001) after treatment. The intragroup comparison showed a significant (P < 0.05) reduction in MMSE score in group A, and in HbA1c (P = 0.01) in group B. CONCLUSION Vildagliptin in addition to metformin resulted in the maintenance of MMSE score, showing a protecting role on cognitive functioning compared to the metformin only group.
Collapse
Affiliation(s)
- Antonio Maria Borzì
- Department of Clinical and Experimental Medicine, Specialization School in Geriatrics, University of Catania, AOU Policlinico, Catania, Italy.
| | - Giovanni Condorelli
- Department of Clinical and Experimental Medicine, Specialization School in Geriatrics, University of Catania, AOU Policlinico, Catania, Italy.
| | - Antonio Biondi
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| | - Francesco Basile
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| | - Enzo Saretto Dante Vicari
- Department of Clinical and Experimental Medicine, Specialization School in Geriatrics, University of Catania, AOU Policlinico, Catania, Italy.
| | - Carola Buscemi
- Department of Clinical and Experimental Medicine, Specialization School in Geriatrics, University of Catania, AOU Policlinico, Catania, Italy.
| | - Salvatore Luca
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| | - Marco Vacante
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| |
Collapse
|
11
|
Erbil D, Eren CY, Demirel C, Küçüker MU, Solaroğlu I, Eser HY. GLP-1's role in neuroprotection: a systematic review. Brain Inj 2019; 33:734-819. [PMID: 30938196 DOI: 10.1080/02699052.2019.1587000] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) is a target for treatment of diabetes; however, its function in the brain is not well studied. In this systematic review, we aimed to analyze the neuroprotective role of GLP-1 and its defined mechanisms. Methods: We searched 'Web of Science' and 'Pubmed' to identify relevant studies using GLP-1 as the keyword. Two hundred and eighty-nine clinical and preclinical studies have been included. Data have been presented by grouping neurodegenerative, neurovascular and specific cell culture models. Results: Recent literature shows that GLP-1 and its agonists, DPP-4 inhibitors and combined GLP-1/GIP molecules are effective in partially or fully reversing the effects of neurotoxic compounds, neurovascular complications of diabetes, neuropathological changes related with Alzheimer's disease, Parkinson's disease or vascular occlusion. Possible mechanisms that provide neuroprotection are enhancing the viability of the neurons and restoring neurite outgrowth by increased neurotrophic factors, increasing subventricular zone progenitor cells, decreasing apoptosis, decreasing the level of pro-inflammatory factors, and strengthening blood-brain barrier. Conclusion: Based on the preclinical studies, GLP-1 modifying agents are promising targets for neuroprotection. On the other hand, the number of clinical studies that investigate GLP-1 as a treatment is low and further clinical trials are needed for a benchside to bedside translation of recent findings.
Collapse
Affiliation(s)
- Damla Erbil
- a School of Medicine , Koç University , Istanbul , Turkey
| | - Candan Yasemin Eren
- b Research Center for Translational Medicine , Koç University , Istanbul , Turkey
| | - Cağrı Demirel
- a School of Medicine , Koç University , Istanbul , Turkey
| | | | - Ihsan Solaroğlu
- a School of Medicine , Koç University , Istanbul , Turkey.,b Research Center for Translational Medicine , Koç University , Istanbul , Turkey
| | - Hale Yapıcı Eser
- a School of Medicine , Koç University , Istanbul , Turkey.,b Research Center for Translational Medicine , Koç University , Istanbul , Turkey
| |
Collapse
|
12
|
Li H, Cao L, Ren Y, Jiang Y, Xie W, Li D. GLP-1 receptor regulates cell growth through regulating IDE expression level in Aβ1-42-treated PC12 cells. Biosci Rep 2018; 38:BSR20171284. [PMID: 29263141 PMCID: PMC6043719 DOI: 10.1042/bsr20171284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/12/2017] [Accepted: 12/19/2017] [Indexed: 12/25/2022] Open
Abstract
This study aimed to validate whether glucagon-like peptide-1 receptor (GLP-1R) / cyclic adenosine monophosphate (cAMP) / protein kinase (PKA) / insulin-degrading enzyme (IDE) signaling pathway was associated with neuronal apoptosis. We developed an animal model presenting both Alzheimer's disease (AD) and type 2 diabetes (T2D), by crossing APP/PS1 mice (AD model) with streptozotocin (STZ)-treated mice (a T2D model). Neuronal apoptosis was detected by TUNEL staining and the expression levels of apoptosis-related proteins were examined by Western blotting. The viability of PC12 cells was analyzed by MTT assay and apoptosis of PC12 cells was detected by flow cytometry. The mRNA expression level was detected by qRT-PCR. T2D contributes to AD progress by prompting neuronal apoptosis and increasing expression of pro-apoptotic protein. β-Amyloid peptide1-42 (Aβ1-42) was shown to exert effects on inhibiting cell viability and prompting cell apoptosis of PC12 cells. However, GLP-1R agonist geniposide (Gen) significantly reversed them, exerting a protective role on PC12 cells. And IDE antagonist bacitracin (Bac) markedly reversed the protective effects of Gen on Aβ1-42-treated PC12 cells. Besides, Gen significantly reversed the effects of Aβ1-42 treatment on IDE expression, and the inhibitor of cAMP/PKA signaling pathway markedly reversed the effects of Gen on IDE expression level in Aβ1-42-treated PC12 cells. In conclusion, GLP-1R regulates cell growth, at least partially, through regulating cAMP/PKA/IDE signaling pathway in Aβ1-42-treated PC12 cells.
Collapse
Affiliation(s)
- Huajie Li
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| | - Liping Cao
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| | - Yi Ren
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| | - Ying Jiang
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| | - Wei Xie
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| | - Dawen Li
- Department of Neurology, the First People's Hospital of Chang Zhou, Jiang Su 213003, China
| |
Collapse
|
13
|
Angelopoulou E, Piperi C. DPP-4 inhibitors: a promising therapeutic approach against Alzheimer's disease. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:255. [PMID: 30069457 DOI: 10.21037/atm.2018.04.41] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD), the commonest cause of dementia in ageing adults, is characterized by gradual cognitive impairment and severe functional disability. Key pathophysiological hallmarks involve amyloid-β (Aβ) accumulation, tau hyper-phosphorylation and neuronal loss. Despite extensive basic and clinical investigations, the etiology of the disease remains elusive, although several risk factors have been associated with its development. Current pharmacotherapies including achetylocholinesterase inhibitors and memantine fail to halt disease progression. Interestingly, type 2 diabetes mellitus (T2DM) and AD share several common characteristics, including Aβ deposition, insulin resistance, degeneration, mitochondrial dysfunction, oxidative stress and excessive inflammation. Recent experimental and clinical evidence indicates that dipeptidyl peptidase-4 (DPP-4) inhibitors, being currently used for T2DM therapy, may also prove effective for AD treatment. They may specifically suppress Aβ accumulation, tau hyper-phosphorylation, neuroinflammation, mitochondrial dysfunction and reactive oxygen species (ROS) formation, resulting in the inhibition of cognitive impairment. In this review, we discuss the encouraging current data regarding the molecular and clinical effects of DPP-4 inhibitors in AD, highlighting the need of future studies elucidating their functional role in addressing this incurable disease.
Collapse
Affiliation(s)
- Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|
14
|
Gumuslu E, Cine N, Ertan M, Mutlu O, Komsuoglu Celikyurt I, Ulak G. Exenatide upregulates gene expression of glucagon-like peptide-1 receptor and nerve growth factor in streptozotocin/nicotinamide-induced diabetic mice. Fundam Clin Pharmacol 2017; 32:174-180. [DOI: 10.1111/fcp.12329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 09/15/2017] [Accepted: 10/25/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Esen Gumuslu
- Department of Medical Genetics; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| | - Naci Cine
- Department of Medical Genetics; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| | - Merve Ertan
- Department of Medical Genetics; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| | - Oguz Mutlu
- Department of Medical Pharmacology; Psychopharmacology Lab.; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| | - Ipek Komsuoglu Celikyurt
- Department of Medical Pharmacology; Psychopharmacology Lab.; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| | - Guner Ulak
- Department of Medical Pharmacology; Psychopharmacology Lab.; Medical Faculty; Kocaeli University; Kocaeli 41380 Turkey
| |
Collapse
|
15
|
Isik AT, Soysal P, Yay A, Usarel C. The effects of sitagliptin, a DPP-4 inhibitor, on cognitive functions in elderly diabetic patients with or without Alzheimer's disease. Diabetes Res Clin Pract 2017; 123:192-198. [PMID: 28056430 DOI: 10.1016/j.diabres.2016.12.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/08/2016] [Indexed: 11/25/2022]
Abstract
AIMS The present study aimed to evaluate effect of sitagliptin, a dipeptidyl peptidase-4 inhibitor (DPP-4I), on cognitive functions in elderly diabetic patients with and without cognitive impairment. METHODS 253 elderly patients with type 2DM, were enrolled in this prospective and observational study. After comprehensive geriatric assessment, the patients were divided into either sitagliptin or non-sitagliptin group. RESULTS A total of 205 patients who completed the study (52 with Alzheimer's Disease (AD)) were re-evaluated 6months later. Sixth-month evaluation revealed no difference between sitagliptin and non-sitagliptin groups in terms of weight, body mass index, and HbA1c (p>0.05). However, the number of patients that required reduced insulin dose was significantly higher in the sitagliptin group (p=0.01). Sitagliptin therapy was associated with an increase in the Mini-Mental State Examination (MMSE) scores (p=0.034); patients without AD receiving only sitagliptin or insulin showed higher MMSE scores as compared to the patients receiving metformin alone (p=0.024). Likewise, the change in MMSE scores in AD patients receiving sitagliptin was significant and indicated improvement as compared to the patients receiving metformin (p=0.047). CONCLUSION Besides its effects similar to those of insulin and metformin in glycemic control and in reducing need for insulin, 6-month sitagliptin therapy may also associated with improvement of cognitive function in elderly diabetic patients with and without AD. Further randomized controlled trials are needed to support these results.
Collapse
Affiliation(s)
- Ahmet Turan Isik
- Center for Aging Brain and Dementia, Department of Geriatric Medicine, Dokuz Eylul University, Faculty of Medicine, Izmir, Turkey.
| | - Pinar Soysal
- Center for Aging Brain and Dementia, Department of Geriatric Medicine, Dokuz Eylul University, Faculty of Medicine, Izmir, Turkey
| | - Adnan Yay
- Department of Internal Medicine, Izmir Military Hospital, Izmir, Turkey
| | - Cansu Usarel
- Center for Aging Brain and Dementia, Department of Geriatric Medicine, Dokuz Eylul University, Faculty of Medicine, Izmir, Turkey
| |
Collapse
|
16
|
Gumuslu E, Mutlu O, Celikyurt IK, Ulak G, Akar F, Erden F, Ertan M. Exenatide enhances cognitive performance and upregulates neurotrophic factor gene expression levels in diabetic mice. Fundam Clin Pharmacol 2016; 30:376-84. [PMID: 26935863 DOI: 10.1111/fcp.12192] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 02/22/2016] [Accepted: 02/26/2016] [Indexed: 12/25/2022]
Abstract
Exenatide is a potent and selective agonist for the GLP-1 (glucagon-like peptide-1) receptor. Recent studies are focused on the effects of GLP-1 analogues on hippocampal neurogenesis, cognition, learning and memory functions. The aim of this study was to assess the effects of chronic exenatide treatment (0.1 μg/kg, s.c, twice daily for 2 weeks) on spatial memory functions by using the modified elevated plus maze (mEPM) test and emotional memory functions by using the passive avoidance (PA) test in streptozotocin/nicotinamide (STZ-NA)-induced diabetic mice. As the genes involved in neurite remodelling are among the primary targets of regulation, the effects of diabetes and chronic administration of exenatide on brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) messenger ribonucleic acid (mRNA) levels in the hippocampus of mice were also determined using quantitative real-time polymerase chain reaction (RT-PCR). This study revealed that in the mEPM and PA tests, type-2 diabetes-induced mice exhibited significant impairment of learning and memory which were ameliorated by GLP-1 receptor agonist exenatide. Quantitative RT-PCR revealed that CREB and BDNF gene expression levels were downregulated in diabetic mice, and these alterations were increased by exenatide treatment. Since, exenatide improves cognitive ability in STZ/NA-induced diabetic mice and activates molecular mechanisms of memory storage in response to a learning experience, it may be a candidate for alleviation of mood and cognitive disorder.
Collapse
Affiliation(s)
- Esen Gumuslu
- Department of Medical Genetics, Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Oguz Mutlu
- Department of Medical Pharmacology, Psychopharmacology Lab., Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Ipek K Celikyurt
- Department of Medical Pharmacology, Psychopharmacology Lab., Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Guner Ulak
- Department of Medical Pharmacology, Psychopharmacology Lab., Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Furuzan Akar
- Department of Medical Pharmacology, Psychopharmacology Lab., Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Faruk Erden
- Department of Medical Pharmacology, Psychopharmacology Lab., Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| | - Merve Ertan
- Department of Medical Genetics, Medical Faculty, Kocaeli University, Kocaeli, 41380, Turkey
| |
Collapse
|
17
|
Jiang D, Wang Y, Zang Y, Liu X, Zhao L, Wang Q, Liu C, Feng W, Yin X, Fang Y. Neuroprotective Effects of rhGLP-1 in Diabetic Rats with Cerebral Ischemia/Reperfusion Injury. Drug Dev Res 2016; 77:124-33. [PMID: 26971396 DOI: 10.1002/ddr.21297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 02/05/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Daoli Jiang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy; Xuzhou Medical College; Xuzhou 221004 China
| | - Yitong Wang
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
- Department of Pharmacy Administration and Clinical Pharmacy; Peking University Health Science Center; Beijing 100191 China
| | - Yannan Zang
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
- Department of Pharmacy Administration and Clinical Pharmacy; Peking University Health Science Center; Beijing 100191 China
| | - Xiaofang Liu
- Zhongda Hospital, School of Medicine; Southeast University; Nanjing 210009 China
| | - Libo Zhao
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
| | - Qian Wang
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
| | - Chang Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy; Xuzhou Medical College; Xuzhou 221004 China
| | - Wanyu Feng
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
| | - Xiaoxing Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy; Xuzhou Medical College; Xuzhou 221004 China
| | - Yi Fang
- Department of Pharmacy; Peking University People's Hospital; Beijing 100044 China
| |
Collapse
|
18
|
Sionov RV, Vlahopoulos SA, Granot Z. Regulation of Bim in Health and Disease. Oncotarget 2015; 6:23058-134. [PMID: 26405162 PMCID: PMC4695108 DOI: 10.18632/oncotarget.5492] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 08/08/2015] [Indexed: 11/25/2022] Open
Abstract
The BH3-only Bim protein is a major determinant for initiating the intrinsic apoptotic pathway under both physiological and pathophysiological conditions. Tight regulation of its expression and activity at the transcriptional, translational and post-translational levels together with the induction of alternatively spliced isoforms with different pro-apoptotic potential, ensure timely activation of Bim. Under physiological conditions, Bim is essential for shaping immune responses where its absence promotes autoimmunity, while too early Bim induction eliminates cytotoxic T cells prematurely, resulting in chronic inflammation and tumor progression. Enhanced Bim induction in neurons causes neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Moreover, type I diabetes is promoted by genetically predisposed elevation of Bim in β-cells. On the contrary, cancer cells have developed mechanisms that suppress Bim expression necessary for tumor progression and metastasis. This review focuses on the intricate network regulating Bim activity and its involvement in physiological and pathophysiological processes.
Collapse
Affiliation(s)
- Ronit Vogt Sionov
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Spiros A. Vlahopoulos
- First Department of Pediatrics, University of Athens, Horemeio Research Laboratory, Thivon and Levadias, Goudi, Athens, Greece
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University, Hadassah Medical School, Jerusalem, Israel
| |
Collapse
|
19
|
Wojsiat J, Prandelli C, Laskowska-Kaszub K, Martín-Requero A, Wojda U. Oxidative Stress and Aberrant Cell Cycle in Alzheimer’s Disease Lymphocytes: Diagnostic Prospects. J Alzheimers Dis 2015; 46:329-50. [DOI: 10.3233/jad-141977] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Joanna Wojsiat
- Laboratory of Preclinical Studies of Higher Standard, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Chiara Prandelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Katarzyna Laskowska-Kaszub
- Laboratory of Preclinical Studies of Higher Standard, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Angeles Martín-Requero
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Urszula Wojda
- Laboratory of Preclinical Studies of Higher Standard, Nencki Institute of Experimental Biology, Warsaw, Poland
| |
Collapse
|
20
|
Hanna A, Connelly KA, Josse RG, McIntyre RS. The non-glycemic effects of incretin therapies on cardiovascular outcomes, cognitive function and bone health. Expert Rev Endocrinol Metab 2015; 10:101-114. [PMID: 30289042 DOI: 10.1586/17446651.2015.972370] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The incretin therapies, glucagon-like peptide-1 receptor agonists and dipeptidyl-peptidase-4 inhibitors, have been developed to lower blood glucose levels in patients with Type 2 diabetes. However, in addition to being a treatment strategy to improve metabolic control, incretin therapies have shown effects independent of glycemic control, including the potential to positively impact cardiovascular events, cognitive deficits and bone mineral density. This paper outlines the non-glycemic effects of incretin therapies on cardiovascular disease, cognitive function and bone health.
Collapse
Affiliation(s)
- Amir Hanna
- a 1 Department of Medicine, University of Toronto, Toronto, ON, Canada
- b 2 Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada
| | - Kim A Connelly
- c 3 Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital and Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Robert G Josse
- a 1 Department of Medicine, University of Toronto, Toronto, ON, Canada
- b 2 Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada
| | - Roger S McIntyre
- d 4 Mood Disorder Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, ON, Canada
- e 5 Department of Psychiatry and Pharmacology, and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
21
|
Rizzo MR, Barbieri M, Boccardi V, Angellotti E, Marfella R, Paolisso G. Dipeptidyl Peptidase-4 Inhibitors Have Protective Effect on Cognitive Impairment in Aged Diabetic Patients With Mild Cognitive Impairment. J Gerontol A Biol Sci Med Sci 2014; 69:1122-31. [DOI: 10.1093/gerona/glu032] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
22
|
Lee S, Tong M, Hang S, Deochand C, de la Monte S. CSF and Brain Indices of Insulin Resistance, Oxidative Stress and Neuro-Inflammation in Early versus Late Alzheimer's Disease. ACTA ACUST UNITED AC 2013; 3:128. [PMID: 25035815 PMCID: PMC4096626 DOI: 10.4172/2161-0460.1000128] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer’s disease (AD) is characterized by progressive impairments in cognitive and behavioral functions with deficits in learning, memory and executive reasoning. Growing evidence points toward brain insulin and insulin-like growth factor (IGF) resistance-mediated metabolic derangements as critical etiologic factors in AD. This suggests that indices of insulin/IGF resistance and their consequences, i.e. oxidative stress, neuro-inflammation, and reduced neuronal plasticity, should be included in biomarker panels for AD. Herein, we examine a range of metabolic, inflammatory, stress, and neuronal plasticity related proteins in early AD, late AD, and aged control postmortem brain, postmortem ventricular fluid (VF), and clinical cerebrospinal fluid (CSF) samples. In AD brain, VF, and CSF samples the trends with respect to alterations in metabolic, neurotrophin, and stress indices were similar, but for pro-inflammatory cytokines, the patterns were discordant. With the greater severities of dementia and neurodegeneration, the differences from control were more pronounced for late AD (VF and brain) than early or moderate AD (brain, VF and CSF). The findings suggest that the inclusion of metabolic, neurotrophin, stress biomarkers in AβPP-Aβ+pTau CSF-based panels could provide more information about the status and progression of neurodegeneration, as well as aid in predicting progression from early- to late-stage AD. Furthermore, standardized multi-targeted molecular assays of neurodegeneration could help streamline postmortem diagnoses, including assessments of AD severity and pathology.
Collapse
Affiliation(s)
- Sarah Lee
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Providence, RI, USA
| | - Ming Tong
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Providence, RI, USA
| | - Steven Hang
- Department of Medicine, Warren Alpert Medical School, Providence, RI, USA
| | - Chetram Deochand
- Departments of Medicine, Rhode Island Hospital, Brown University, Providence, RI, USA
| | - Suzanne de la Monte
- Department of Medicine, Pathology (Neuropathology), Neurology and Neurosurgery, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, RI, USA
| |
Collapse
|
23
|
Salcedo I, Tweedie D, Li Y, Greig NH. Neuroprotective and neurotrophic actions of glucagon-like peptide-1: an emerging opportunity to treat neurodegenerative and cerebrovascular disorders. Br J Pharmacol 2012; 166:1586-99. [PMID: 22519295 DOI: 10.1111/j.1476-5381.2012.01971.x] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Like type-2 diabetes mellitus (T2DM), neurodegenerative disorders and stroke are an ever increasing, health, social and economic burden for developed Westernized countries. Age is an important risk factor in all of these; due to the rapidly increasing rise in the elderly population T2DM and neurodegenerative disorders, both represent a looming threat to healthcare systems. Whereas several efficacious drugs are currently available to ameliorate T2DM, effective treatments to counteract pathogenic processes of neurodegenerative disorders are lacking and represent a major scientific and pharmaceutical challenge. Epidemiological data indicate an association between T2DM and most major neurodegenerative disorders, including Alzheimer's and Parkinson's diseases. Likewise, there is an association between T2DM and stroke incidence. Studies have revealed that common pathophysiological features, including oxidative stress, insulin resistance, abnormal protein processing and cognitive decline, occur across these. Based on the presence of shared mechanisms and signalling pathways in these seemingly distinct diseases, one could hypothesize that an effective treatment for one disorder could prove beneficial in the others. Glucagon-like peptide-1 (GLP-1)-based anti-diabetic drugs have drawn particular attention as an effective new strategy to not only regulate blood glucose but also to reduce apoptotic cell death of pancreatic beta cells in T2DM. Evidence supports a neurotrophic and neuroprotective role of GLP-1 receptor (R) stimulation in an increasing array of cellular and animal neurodegeneration models as well as in neurogenesis. Herein, we review the physiological role of GLP-1 in the nervous system, focused towards the potential benefit of GLP-1R stimulation as an immediately translatable treatment strategy for acute and chronic neurological disorders.
Collapse
Affiliation(s)
- Isidro Salcedo
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | | | | | | |
Collapse
|
24
|
McIntyre RS, Powell AM, Kaidanovich-Beilin O, Soczynska JK, Alsuwaidan M, Woldeyohannes HO, Kim AS, Gallaugher LA. The neuroprotective effects of GLP-1: possible treatments for cognitive deficits in individuals with mood disorders. Behav Brain Res 2012; 237:164-71. [PMID: 23000536 DOI: 10.1016/j.bbr.2012.09.021] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/10/2012] [Accepted: 09/14/2012] [Indexed: 12/17/2022]
Abstract
Incretins are a group of gastrointestinal hormones detected both peripherally and in the central nervous system (CNS). Recent studies have documented multiple effects of incretins on brain structure and function. Research into the neurological effects of incretins has primarily focused on animal models of neurodegenerative disorders (e.g., Alzheimer's Disease, Huntington's and Parkinson's diseases). Mood disorders (e.g. bipolar disorder (BD), major depressive disorder (MDD)) are associated with similar alterations in brain structure and function, as well as a range of cognitive deficits (e.g. memory, learning, executive function). Brain abnormalities and cognitive deficits are also found in populations with metabolic disorders (e.g., diabetes mellitus Type 2). In addition, individuals with mood disorders often have co-morbid metabolic conditions, thus treatment strategies which can effectively treat both cognitive deficits and metabolic abnormalities represent a possible integrated treatment avenue. In particular, glucagon-like peptide-1 (GLP-1) and its more stable, longer-lasting analogues have been demonstrated to exert neuroprotective and anti-apoptotic effects, reduce beta-amyloid (Aβ) plaque accumulation, modulate long-term potentiation and synaptic plasticity, and promote differentiation of neuronal progenitor cells. In animal models of behaviour, treatment with GLP-1 receptor agonists has been demonstrated to improve measures of cognitive function including learning and memory, as well as reduce depressive behaviour. Available GLP-1 treatments also have a favourable metabolic profile which includes weight loss and reduced risk for hypoglycemia. Systematic evaluation of the effects of GLP-1 treatment in psychiatric populations who evince cognitive deficits represents a promising treatment avenue.
Collapse
Affiliation(s)
- Roger S McIntyre
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Fu Z, Kuang HY, Hao M, Gao XY, Liu Y, Shao N. Protection of exenatide for retinal ganglion cells with different glucose concentrations. Peptides 2012; 37:25-31. [PMID: 22727809 DOI: 10.1016/j.peptides.2012.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 06/12/2012] [Accepted: 06/12/2012] [Indexed: 12/30/2022]
Abstract
Exendin-4 is a peptide resembling glucagon-like peptide-1 (GLP-1), which has protective effects on nerve cells. However, the effects of Exendin-4 on retinal ganglion cells (RGC) are still under clear. The purpose of the present study is to demonstrate that exenatide prevents high- or low-glucose-induced retinal ganglion cell impairment. We observed the expression of GLP-1R in RGC-5 cells by immunofluorescence and Western blot. To investigate the effect of exenatide on RGC-5 cells incubated different glucose concentrations, CCK-8 measured the survival rates and electron microscopy detected cellular injury. The expression levels of Bcl-2 and Bax were analyzed by immunocytochemistry and Western blot. Exenatide protects RGC-5 from high- or low-glucose-induced cellular injury and the optimum concentration was 0.5μg/ml. Exenatide can inhibit high- or low-glucose-induced mitochondrial changes. Exenatide protects RGC-5 from high- or low-glucose-induced Bax increased and Bcl-2 decreased. Furthermore, the protective effect of exenatide could be inhibited by Exendin (9-39). These findings indicate that exenatide shows a neuroprotective effect for different glucose concentrations-induced RGC-5 cells injury. Exenatide could protect RGC-5 cells from degeneration or death, which may protect retinal function and have a potential value for patients with diabetic retinopathy.
Collapse
Affiliation(s)
- Zheng Fu
- Department of Endocrinology, Ningde Hospital, 352100 Fujian Province, China
| | | | | | | | | | | |
Collapse
|
26
|
Hao M, Kuang HY, Fu Z, Gao XY, Liu Y, Deng W. Exenatide prevents high-glucose-induced damage of retinal ganglion cells through a mitochondrial mechanism. Neurochem Int 2012; 61:1-6. [DOI: 10.1016/j.neuint.2012.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 04/01/2012] [Accepted: 04/10/2012] [Indexed: 12/31/2022]
|
27
|
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]
|
28
|
Abstract
Incretin-based therapies have established a foothold in the diabetes armamentarium through the introduction of oral dipeptidyl peptidase-4 inhibitors and the injectable class, the glucagon-like peptide-1 receptor agonists. In 2009, the American Diabetes Association and European Association for the Study of Diabetes authored a revised consensus algorithm for the initiation and adjustment of therapy in Type 2 diabetes (T2D). The revised algorithm accounts for the entry of incretin-based therapies into common clinical practice, especially where control of body weight and hypoglycemia are concerns. The gut-borne incretin hormones have powerful effects on glucose homeostasis, particularly in the postprandial period, when approximately two-thirds of the β-cell response to a given meal is due to the incretin effect. There is also evidence that the incretin effect is attenuated in patients with T2D, whereby the β-cell becomes less responsive to incretin signals. The foundation of incretin-based therapies is to target this previously unrecognized feature of diabetes pathophysiology, resulting in sustained improvements in glycemic control and improved body weight control. In addition, emerging evidence suggests that incretin-based therapies may have a positive impact on inflammation, cardiovascular and hepatic health, sleep, and the central nervous system. In the present article, we discuss the attributes of current and near-future incretin-based therapies.
Collapse
|
29
|
Cai H, Cong WN, Ji S, Rothman S, Maudsley S, Martin B. Metabolic dysfunction in Alzheimer's disease and related neurodegenerative disorders. Curr Alzheimer Res 2012; 9:5-17. [PMID: 22329649 DOI: 10.2174/156720512799015064] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 07/17/2011] [Accepted: 08/09/2011] [Indexed: 01/14/2023]
Abstract
Alzheimer's disease and other related neurodegenerative diseases are highly debilitating disorders that affect millions of people worldwide. Efforts towards developing effective treatments for these disorders have shown limited efficacy at best, with no true cure to this day being present. Recent work, both clinical and experimental, indicates that many neurodegenerative disorders often display a coexisting metabolic dysfunction which may exacerbate neurological symptoms. It stands to reason therefore that metabolic pathways may themselves contain promising therapeutic targets for major neurodegenerative diseases. In this review, we provide an overview of some of the most recent evidence for metabolic dysregulation in Alzheimer's disease, Huntington's disease, and Parkinson's disease, and discuss several potential mechanisms that may underlie the potential relationships between metabolic dysfunction and etiology of nervous system degeneration. We also highlight some prominent signaling pathways involved in the link between peripheral metabolism and the central nervous system that are potential targets for future therapies, and we will review some of the clinical progress in this field. It is likely that in the near future, therapeutics with combinatorial neuroprotective and 'eumetabolic' activities may possess superior efficacies compared to less pluripotent remedies.
Collapse
Affiliation(s)
- Huan Cai
- Metabolism Unit, National Institute on Aging, Baltimore, MD 21224, USA
| | | | | | | | | | | |
Collapse
|
30
|
de la Monte SM. Early intranasal insulin therapy halts progression of neurodegeneration: progress in Alzheimer's disease therapeutics. ACTA ACUST UNITED AC 2012; 8:61-64. [PMID: 26855666 DOI: 10.2217/ahe.11.89] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Evaluation of Craft S, Baker LD, Montine TJ, Minoshima S, Watson GS, Claxton A, et al. Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment: A Pilot Clinical Trial. Arch Neurol. 2011 Sep 12. Alzheimer's disease is associated with brain insulin deficiency and insulin resistance, similar to the problems in diabetes. If insulin could be supplied to the brain in the early stages of Alzheimer's, subsequent neurodegeneration might be prevented. Administering systemic insulin to elderly non-diabetics poses unacceptable risks of inadvertant hypoglycemia. However, intranasal delivery directs the insulin into the brain, avoiding systemic side-effects. This pilot study demonstrates both efficacy and safety of using intranasal insulin to treat early Alzheimer's and mild cognitive impairment, i.e. the precursor to Alzheimer's. Significant improvements in learning, memory, and cognition occured within a few months, but without intranasal insulin, brain function continued to deteriorate in measurable degrees. Intranasal insulin therapy holds promise for halting progression of Alzheimer's disease.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Departments of Pathology (Neuropathology), Neurology, Neurosurgery, and Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI
| |
Collapse
|
31
|
de la Monte SM. Contributions of brain insulin resistance and deficiency in amyloid-related neurodegeneration in Alzheimer's disease. Drugs 2012; 72:49-66. [PMID: 22191795 PMCID: PMC4550303 DOI: 10.2165/11597760-000000000-00000] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in North America. Growing evidence supports the concept that AD is fundamentally a metabolic disease that results in progressive impairment in the brain's capacity to utilize glucose and respond to insulin and insulin-like growth factor (IGF) stimulation. Moreover, the heterogeneous nature of AD is only partly explained by the brain's propensity to accumulate aberrantly processed, misfolded and aggregated oligomeric structural proteins, including amyloid-β peptides and hyperphosphorylated tau. Evidence suggests that other factors, including impaired energy metabolism, oxidative stress, neuroinflammation, insulin and IGF resistance, and insulin/IGF deficiency in the brain should be incorporated into an overarching hypothesis to develop more realistic diagnostic and therapeutic approaches to AD. In this review, the interrelationship between impaired insulin and IGF signalling and amyloid-β pathology is discussed along with potential therapeutic approaches. Impairments in brain insulin/IGF signalling lead to increased expression of amyloid-β precursor protein (AβPP) and accumulation of AβPP-Aβ. In addition, they promote oxidative stress and deficits in energy metabolism, leading to the activation of pro-AβPP-Aβ-mediated neurodegeneration cascades. Although brain insulin/IGF resistance and deficiency can be induced by primary or secondary disease processes, the soaring rates of peripheral insulin resistance associated with obesity, diabetes mellitus and metabolic syndrome quite likely play major roles in the current AD epidemic. Both clinical and experimental data have linked chronic hyperinsulinaemia to cognitive impairment and neurodegeneration with increased AβPP-Aβ accumulation/reduced clearance in the CNS. Correspondingly, both the restoration of insulin responsiveness and the use of insulin therapy can lead to improved cognitive performance, although with variable effects on brain AβPP-Aβ load. On the other hand, experimental evidence supports the concept that the toxic effects of AβPP-Aβ can promote insulin resistance. Together, these findings suggest that a positive feedback loop of progressive neurodegeneration can develop whereby insulin resistance drives AβPP-Aβ accumulation, and AβPP-Aβ fibril toxicity drives brain insulin resistance. This phenomenon could explain why measuring AβPP-Aβ levels in cerebrospinal fluid or imaging of the brain has proven to be inadequate as a stand-alone biomarker for diagnosing AD, and why the clinical trial results of anti-AβPP-Aβ monotherapy have been disappointing. Instead, the aggregate data suggest that brain insulin resistance and deficiency must also be therapeutically targeted to halt AD progression or reverse its natural course. The positive therapeutic effects of different treatments that address the role of brain insulin/IGF resistance and deficiency, including the use of intranasal insulin delivery, incretins and insulin sensitizer agents are discussed along with potential benefits of lifestyle changes to modify risk for developing mild cognitive impairment or AD. Altogether, the data strongly support the notion that we must shift toward the implementation of multimodal rather than unimodal diagnostic and therapeutic strategies for AD.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Department of Pathology, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI 02903, USA.
| |
Collapse
|
32
|
de la Monte SM. Therapeutic targets of brain insulin resistance in sporadic Alzheimer's disease. Front Biosci (Elite Ed) 2012. [PMID: 22201977 DOI: 10.2741/482] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Growing evidence supports roles for brain insulin and insulin-like growth factor (IGF) resistance and metabolic dysfunction in the pathogenesis of Alzheimer's disease (AD). Whether the underlying problem stems from a primary disorder of central nervous system (CNS) neurons and glia, or secondary effects of systemic diseases such as obesity, Type 2 diabetes, or metabolic syndrome, the end-results include impaired glucose utilization, mitochondrial dysfunction, increased oxidative stress, neuroinflammation, and the propagation of cascades that result in the accumulation of neurotoxic misfolded, aggregated, and ubiquitinated fibrillar proteins. This article reviews the roles of impaired insulin and IGF signaling to AD-associated neuronal loss, synaptic disconnection, tau hyperphosphorylation, amyloid-beta accumulation, and impaired energy metabolism, and discusses therapeutic strategies and lifestyle approaches that could be used to prevent, delay the onset, or reduce the severity of AD. Finally, it is critical to recognize that AD is heterogeneous and has a clinical course that fully develops over a period of several decades. Therefore, early and multi-modal preventive and treatment approaches should be regarded as essential.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Department of Neurology, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI, USA.
| |
Collapse
|
33
|
Li L, Zhang ZF, Holscher C, Gao C, Jiang YH, Liu YZ. (Val⁸) glucagon-like peptide-1 prevents tau hyperphosphorylation, impairment of spatial learning and ultra-structural cellular damage induced by streptozotocin in rat brains. Eur J Pharmacol 2011; 674:280-6. [PMID: 22115895 DOI: 10.1016/j.ejphar.2011.11.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 11/01/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
Abstract
It has being shown that glucagon-like peptide-1 (GLP-1), a new anti-diabetes agent, significantly attenuated beta-amyloid (Aβ) levels in rats. In the present study, (Val(8))GLP-1 was used to prevent impairments in memory formation, tau hyperphosphorylation and ultra-structural changes induced by streptozotocin intracerebroventricular (i.c.v.) injection. A spatial water maze task was used to test the rats' learning and memory formation, Western blot was used to measure tau hyperphosphorylation/total tau, and transmission electron microscope was used to find ultra-structural changes. The results shown that streptozotocin induced a series of Alzheimer disease -like changes in behaviour, a significant decline in learning and memory formation, an increased expression of total tau and an increased ratio of phosphorylated tau, and damage to nucleus and nucleolus as seen in electron micrographs. After treatment with (Val(8))GLP-1 (50 μM in 10 μl i.c.v.), there is a significant improvement in learning and memory, a reduction in total tau expression and hyperphosphorylated tau levels, and a recovery of damaged cell nuclei and nucleolus. Our results indicated that (Val(8))GLP-1 might prevent age-related neurodegenerative changes by preventing decline of learning and memory formation, reduction of phosphorylated tau levels and protection of subcellular structures and morphology of neurons. Therefore, (Val(8))GLP-1 is potentially a novel treatment for Alzheimer's disease.
Collapse
Affiliation(s)
- Lin Li
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, PR China
| | | | | | | | | | | |
Collapse
|
34
|
Repeated administration of exendin-4 reduces focal cerebral ischemia-induced infarction in rats. Brain Res 2011; 1427:23-34. [PMID: 22055454 DOI: 10.1016/j.brainres.2011.10.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 09/23/2011] [Accepted: 10/14/2011] [Indexed: 12/20/2022]
Abstract
Exendin-4 is a GLP-1 agonist that is clinically used for the treatment of diabetes mellitus and may also have neuroprotective effect. We explored the effect of repeated administration of exendin-4 (0.5 μg/kg, intraperitoneal twice a day for 7 days) on infarct volume, neurological deficit (neurological score, grip test, foot fault and rota rod tests), oxidative stress parameters (malondialdehyde, reduced glutathione, and superoxide dismutase) and expression of endothelin (ET) ET(A) and ET(B) receptors following cerebral ischemia produced in rats by permanent middle cerebral artery occlusion (MCAO). Since ET(A) receptors in the central nervous system (CNS) are involved in cerebral ischemia, we determined the effect of a specific ET(A) receptor antagonist, BQ123 (1mg/kg, intravenously administered thrice: 30 min, 2h and 4h after MCAO for a total dose of 3 mg/kg) on cerebral ischemia in control and exendin-4 treated rats. Results indicate that exendin-4 treated rats had significant protection following MCAO induced cerebral ischemia. The infarct volume was 27% less compared to vehicle treated rats. The neurological deficit following MCAO was lower and oxidative stress parameters were improved in exendin-4 treated rats compared to control. BQ123 significantly improved infarct volume, oxidative stress parameters and neurological deficit in ischemic rats treated with vehicle or exendin-4. BQ123 induced protection from cerebral ischemia was similar in vehicle or exendin-4 treated rats. Expression of ET(A) receptors was significantly increased following cerebral ischemia which was not affected by exendin-4 treatment or by BQ123 administration. No change in expression of ET(B) receptors was observed following cerebral ischemia or any treatment. It is concluded that exendin-4 protects the CNS from damage due to cerebral ischemia by reducing oxidative stress and is independent of ET receptor involvement.
Collapse
|
35
|
Glucagon-like peptide-1, diabetes, and cognitive decline: possible pathophysiological links and therapeutic opportunities. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:281674. [PMID: 21747826 PMCID: PMC3124026 DOI: 10.1155/2011/281674] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 04/05/2011] [Indexed: 12/23/2022]
Abstract
Metabolic and neurodegenerative disorders have a growing prevalence in Western countries. Available epidemiologic and neurobiological evidences support the existence of a pathophysiological link between these conditions. Glucagon-like peptide 1 (GLP-1), whose activity is reduced in insulin resistance, has been implicated in central nervous system function, including cognition, synaptic plasticity, and neurogenesis. We review the experimental researches suggesting that GLP-1 dysfunction might be a mediating factor between Type 2 diabetes mellitus (T2DM) and neurodegeneration. Drug treatments enhancing GLP-1 activity hold out hope for treatment and prevention of Alzheimer's disease (AD) and cognitive decline.
Collapse
|
36
|
Vrang N, Larsen PJ. Preproglucagon derived peptides GLP-1, GLP-2 and oxyntomodulin in the CNS: role of peripherally secreted and centrally produced peptides. Prog Neurobiol 2010; 92:442-62. [PMID: 20638440 DOI: 10.1016/j.pneurobio.2010.07.003] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 07/01/2010] [Accepted: 07/10/2010] [Indexed: 12/16/2022]
Abstract
The scientific understanding of preproglucagon derived peptides has provided people with type 2 diabetes with two novel classes of glucose lowering agents, the dipeptidyl peptidase IV (DPP-IV) inhibitors and GLP-1 receptor agonists. For the scientists, the novel GLP-1 agonists, and DPP-IV inhibitors have evolved as useful tools to understand the role of the preproglucagon derived peptides in normal physiology and disease. However, the overwhelming interest attracted by GLP-1 analogues as potent incretins has somewhat clouded the efforts to understand the importance of preproglucagon derived peptides in other physiological contexts. In particular, our neurobiological understanding of the preproglucagon expressing neuronal pathways in the central nervous system as well as the degree to which central GLP-1 receptors are targeted by peripherally administered GLP-1 receptor agonists is still fairly limited. The role of GLP-1 as an anorectic neurotransmitter is well recognized, but clarification of the neuronal targets and physiological basis of this response is further warranted, as is the mapping of GLP-1 sensitive neurons involved in a variety of neuroendocrine and behavioral responses. Further recent evidence points to GLP-1 as a central neuropeptide with neuroprotective capabilities potentially mitigating a wide array of neurodegenerative conditions. It is the aim of the present review to summarize our current understanding of preproglucagon derived peptides as neurotransmitters in the central nervous system.
Collapse
Affiliation(s)
- Niels Vrang
- Gubra ApS, Ridebanevej 12, 1870 Frederiksberg, Denmark.
| | | |
Collapse
|
37
|
Gengler S, McClean PL, McCurtin R, Gault VA, Hölscher C. Val(8)GLP-1 rescues synaptic plasticity and reduces dense core plaques in APP/PS1 mice. Neurobiol Aging 2010; 33:265-76. [PMID: 20359773 DOI: 10.1016/j.neurobiolaging.2010.02.014] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Revised: 02/04/2010] [Accepted: 02/19/2010] [Indexed: 01/09/2023]
Abstract
Diabetes is a risk factor for Alzheimer's disease. We tested the effects of Val(8)GLP-1, an enzyme-resistant analogue of the incretin hormone glucagon-like peptide 1 originally developed to treat diabetes in a mouse model of Alzheimer's disease that expresses mutated amyloid precursor protein (APP) and presenilin-1. We tested long term potentiation (LTP) of synaptic plasticity, inflammation response, and plaque formation. Val(8)GLP-1 crosses the blood-brain barrier when administered via intraperitoneal injection. Val(8)GLP-1 protected LTP in 9- and 18-month-old Alzheimer's disease mice when given for 3 weeks at 25 nmol/kg intraperitoneally. LTP was also enhanced in 18-month-old wild type mice, indicating that Val(8)GLP-1 also ameliorates age-related synaptic degenerative processes. Paired-pulse facilitation was also enhanced. The number of beta-amyloid plaques and microglia activation in the cortex increased with age but was not reduced by Val(8)GLP-1. In 18-month-old mice, however, the number of Congo red positive dense-core amyloid plaques was reduced. Treatment with Val(8)GLP-1 might prevent or delay neurodegenerative processes.
Collapse
Affiliation(s)
- Simon Gengler
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | | | | | | | | |
Collapse
|
38
|
Jin HY, Liu WJ, Park JH, Baek HS, Park TS. Effect of dipeptidyl peptidase-IV (DPP-IV) inhibitor (Vildagliptin) on peripheral nerves in streptozotocin-induced diabetic rats. Arch Med Res 2010; 40:536-44. [PMID: 20082866 DOI: 10.1016/j.arcmed.2009.09.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 09/07/2009] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND AIMS The aim of this study was to investigate the GLP-1 pathway effect on peripheral nerves using a DPP-IV inhibitor in streptozotocin (STZ)-induced diabetic rats. METHODS Adult male Sprague Dawley rats were divided into four groups and two groups (n=6 in each) were given a DPP-IV inhibitor of 0.3mg/kg/day or 10mg/kg/day dissolved in water. Intraepidermal innervation was quantified as nerve fiber abundance per unit length of epidermis (IENF/mm) following an immunohistochemical procedure using the polyclonal antibody of anti-protein gene product 9.5 (PGP 9.5). RESULTS Daily administration of DPP-IV inhibitor to the experimental diabetes model at doses of 10mg/kg for 32 weeks protected nerve fiber loss compared with untreated rats as follows (IENF/mm): normal (9.89+/-0.34), diabetes mellitus (DM) (8.42+/-0.28), DM with 0.3mg/kg DPP-IV inhibitor (9.88+/-0.38), and DM with 10mg/kg DPP-IV inhibitor (10.36+/-0.32) (p<0.05). There was a significant reduction (% change) in the decrease of intraepidermal nerve fiber density (IENFD) in the DPP-IV inhibitor-treated groups during the experimental period: normal (10.1%), DM (25.8%), DM with 0.3mg/kg DPP-IV inhibitor (13.3%), and DM with 10mg/kg DPP-IV inhibitor (7.9%) (p<0.05). CONCLUSIONS Our study suggests that a DPP-IV inhibitor may prevent peripheral nerve degeneration in a diabetes-induced animal model and support the idea that GLP-1 may be useful in peripheral neuropathy.
Collapse
Affiliation(s)
- Heung Yong Jin
- Department of Internal Medicine, Research Institute of Clinical Medicine, Chonbuk National University Medical School, Jeonju, South Korea
| | | | | | | | | |
Collapse
|
39
|
McIntosh CHS, Widenmaier S, Kim SJ. Pleiotropic actions of the incretin hormones. VITAMINS AND HORMONES 2010; 84:21-79. [PMID: 21094896 DOI: 10.1016/b978-0-12-381517-0.00002-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The insulin secretory response to a meal results largely from glucose stimulation of the pancreatic islets and both direct and indirect (autonomic) glucose-dependent stimulation by incretin hormones released from the gastrointestinal tract. Two incretins, Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), have so far been identified. Localization of the cognate G protein-coupled receptors for GIP and GLP-1 revealed that they are present in numerous tissues in addition to the endocrine pancreas, including the gastrointestinal, cardiovascular, central nervous and autonomic nervous systems (ANSs), adipose tissue, and bone. At these sites, the incretin hormones exert a range of pleiotropic effects, many of which contribute to the integration of processes involved in the regulation of food intake, and nutrient and mineral processing and storage. From detailed studies at the cellular and molecular level, it is also evident that both incretin hormones act via multiple signal transduction pathways that regulate both acute and long-term cell function. Here, we provide an overview of current knowledge relating to the physiological roles of GIP and GLP-1, with specific emphasis on their modes of action on islet hormone secretion, β-cell proliferation and survival, central and autonomic neuronal function, gastrointestinal motility, and glucose and lipid metabolism. However, it is emphasized that despite intensive research on the various body systems, in many cases there is uncertainty as to the pathways by which the incretins mediate their pleiotropic effects and only a rudimentary understanding of the underlying cellular mechanisms involved, and these are challenges for the future.
Collapse
Affiliation(s)
- Christopher H S McIntosh
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | |
Collapse
|
40
|
Glucagon-like peptide-1 analogues enhance synaptic plasticity in the brain: a link between diabetes and Alzheimer's disease. Eur J Pharmacol 2009; 630:158-62. [PMID: 20035739 DOI: 10.1016/j.ejphar.2009.12.023] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 11/25/2009] [Accepted: 12/15/2009] [Indexed: 01/27/2023]
Abstract
Type 2 diabetes has been identified as a risk factor for patients with Alzheimer's disease. Insulin signalling is often impaired in Alzheimer's disease, contributing to the neurodegenerative process. One potential strategy to help prevent this is the normalisation of insulin signalling in the brain. Therefore, the present study was designed to test the effects of novel enzyme-resistant analogues of the insulin-releasing incretin hormone, glucagon-like peptide 1 (GLP-1). The effects of Liraglutide (Victoza) and other novel GLP-1 analogues were tested on synaptic plasticity (LTP) in area CA1 of the hippocampus. At a dose of 15nmol in 5microl i.c.v., Liraglutide (P<0.005), Asp(7)GLP-1 (P<0.001), N-glyc-GLP-1 (P<0.01), and Pro(9)GLP-1 (P<0.001). In contrast, the GLP-1 receptor antagonist exendin(9-39)amide impaired LTP (P<0.001). Co-injection of exendin(9-39) and Liraglutide showed no effect on LTP. These results clearly demonstrate that Liraglutide and other GLP-1 analogues elicit effects on neurotransmission in the brain. Furthermore, GLP-1 peptides are not only effective in modulating insulin-release and achieving glycaemic control in type 2 diabetes, but are also effective in modulating synaptic plasticity. These findings are consistent with our previous observations that the novel analogue (Val(8))GLP-1 enhances LTP and reverses the impairments of LTP induced by beta-amyoid fragments. Therefore, the drug effects seen here could potentially ameliorate the impairments in neuronal communication and cognitive processes observed in Alzheimer's disease.
Collapse
|
41
|
Impairment of synaptic plasticity and memory formation in GLP-1 receptor KO mice: Interaction between type 2 diabetes and Alzheimer's disease. Behav Brain Res 2009; 205:265-71. [DOI: 10.1016/j.bbr.2009.06.035] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 06/20/2009] [Accepted: 06/22/2009] [Indexed: 12/12/2022]
|
42
|
Chapter MC, White CM, DeRidder A, Chadwick W, Martin B, Maudsley S. Chemical modification of class II G protein-coupled receptor ligands: frontiers in the development of peptide analogs as neuroendocrine pharmacological therapies. Pharmacol Ther 2009; 125:39-54. [PMID: 19686775 DOI: 10.1016/j.pharmthera.2009.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 07/24/2009] [Indexed: 01/08/2023]
Abstract
Recent research and clinical data have begun to demonstrate the huge potential therapeutic importance of ligands that modulate the activity of the secretin-like, Class II, G protein-coupled receptors (GPCRs). Ligands that can modulate the activity of these Class II GPCRs may have important clinical roles in the treatment of a wide variety of conditions such as osteoporosis, diabetes, amyotrophic lateral sclerosis and autism spectrum disorders. While these receptors present important new therapeutic targets, the large glycoprotein nature of their cognate ligands poses many problems with respect to therapeutic peptidergic drug design. These native peptides often exhibit poor bioavailability, metabolic instability, poor receptor selectivity and resultant low potencies in vivo. Recently, increased attention has been paid to the structural modification of these peptides to enhance their therapeutic efficacy. Successful modification strategies have included d-amino acid substitutions, selective truncation, and fatty acid acylation of the peptide. Through these and other processes, these novel peptide ligand analogs can demonstrate enhanced receptor subtype selectivity, directed signal transduction pathway activation, resistance to proteolytic degradation, and improved systemic bioavailability. In the future, it is likely, through additional modification strategies such as addition of circulation-stabilizing transferrin moieties, that the therapeutic pharmacopeia of drugs targeted towards Class II secretin-like receptors may rival that of the Class I rhodopsin-like receptors that currently provide the majority of clinically used GPCR-based therapeutics. Currently, Class II-based drugs include synthesized analogs of vasoactive intestinal peptide for type 2 diabetes or parathyroid hormone for osteoporosis.
Collapse
Affiliation(s)
- Megan C Chapter
- Receptor Pharmacology Unit, Laboratory of Neuroscience, National Institute on Aging, Biomedical Research Center, 251 Bayview Blvd., Baltimore MD 21224, USA
| | | | | | | | | | | |
Collapse
|
43
|
Gezginci-Oktayoglu S, Bolkent S. Exendin-4 exerts its effects through the NGF/p75NTR system in diabetic mouse pancreas. Biochem Cell Biol 2009; 87:641-51. [PMID: 19767827 DOI: 10.1139/o09-046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) ameliorates the symptoms of diabetes through stimulation of insulin secretion. We have investigated the possible components of cellular mechanism triggered by exendin-4, a potent GLP-1 receptor agonist, in streptozotocin (STZ) induced diabetic mice pancreas. BALB/c male mice were divided into four groups for this investigation. The first group was given citrate buffer only, the second group was administered exendin-4 alone, the third group received STZ, and the fourth group was given both STZ and exendin-4. Exendin-4 (3 microg/kg) was administered by daily subcutaneous injection for 30 days after the animals were rendered diabetic by administration of STZ (200 mg/kg). With exendin-4 treatment on diabetic mice, the following results were noted: (i) exendin-4 suppressed the increase in plasma glucose and inhibited somatostatin expression induced by STZ, (ii) reduction of insulin prevalence was inhibited, while expression of p75 neurotrophin receptor (p75NTR), pancreatic nerve growth factor (NGF), and NGF-positive islet cell prevalence increased, (iii) there were no alterations in the severity of proliferated cell nuclear antigen positive or apoptotic beta cells in pancreatic islets, and (iv) pancreatic catalase, glutathione peroxidase, and superoxide dismutase activities significantly increased. In conclusion, these data suggest that exendin-4 might exert its actions through the NGF/p75NTR system and decrease somatostatin expression.
Collapse
Affiliation(s)
- Selda Gezginci-Oktayoglu
- Department of Biology, Istanbul University, Faculty of Science, 34134-Vezneciler, Istanbul, Turkey.
| | | |
Collapse
|
44
|
Neuroprotection of geniposide against hydrogen peroxide induced PC12 cells injury: involvement of PI3 kinase signal pathway. Acta Pharmacol Sin 2009; 30:159-65. [PMID: 19151742 DOI: 10.1038/aps.2008.25] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AIM Oxidative stress plays a critical role in the pathogenic cascade leading to neuronal degeneration in AD. Consequently, the induction of endogenous antioxidative proteins by antioxidants seems to be a very reasonable strategy for delaying the disease's progression. In previous work, we identified the neurotrophic and neuroprotective effects of geniposide, which result from the activation of glucagon-like peptide 1 receptor (GLP-1R). In this study, we explore the role of PI3 kinase signaling pathway in the neuroprotection of geniposide in PC12 cells. METHODS Cell viability was determined by MTT assay. Apoptosis was detected by Hoechst and PI double staining. The protein expression of Bcl-2 and phosphorylation of Akt308, Akt473, GSK-3beta, and PDK1 was measured by Western blot. RESULTS Geniposide induced the expression of the antiapoptotic protein Bcl-2, which inhibited apoptosis in PC12 cells induced by H(2)O(2), and this effect could be inhibited by preincubation with LY294002, a selective inhibitor of PI3K. Furthermore, geniposide enhanced the phosphorylation of Akt308, Akt473, GSK-3beta and PDK1 under conditions of oxidative stress. CONCLUSION These results demonstrate that the PI3K signaling pathway is involved in the neuroprotection of geniposide in PC12 cells against the oxidative damage induced by H(2)O(2) in PC12 cells.
Collapse
|