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McMillan JM, Mele BS, Hogan DB, Leung AA. Impact of pharmacological treatment of diabetes mellitus on dementia risk: systematic review and meta-analysis. BMJ Open Diabetes Res Care 2018; 6:e000563. [PMID: 30487973 PMCID: PMC6254737 DOI: 10.1136/bmjdrc-2018-000563] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/11/2018] [Accepted: 10/01/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The association between diabetes mellitus (DM) treatment and dementia is not well understood. OBJECTIVE To investigate the association between treatment of diabetes, hypoglycemia, and dementia risk. RESEARCH DESIGN AND METHODS We performed a systematic review and meta-analysis of pharmacological treatment of diabetes and incident or progressive cognitive impairment. We searched Ovid MEDLINE, Embase, Cochrane Central Registry of Controlled Trials, and PsychINFO from inception to 18 October 2017. We included cross-sectional, case-control, cohort, and randomized controlled studies. The study was registered with PROSPERO (ID CRD42017077953). RESULTS We included 37 studies into our systematic review and 13 into our meta-analysis. Ten studies investigated any antidiabetic treatment compared with no treatment or as add-on therapy to prior care. Treatment with an antidiabetic agent, in general, was not associated with incident dementia (risk ratio (RR) 1.01; 95% CI 0.93 to 1.10). However, we found differential effects across drug classes, with a signal of harm associated with insulin therapy (RR 1.21; 95% CI 1.06 to 1.39), but potentially protective effects with thiazolidinedione exposure (RR 0.71; 95% CI 0.55 to 0.93). Severe hypoglycemic episodes were associated with a nearly twofold increased likelihood of incident dementia (RR 1.77; 95% CI 1.35 to 2.33). Most studies did not account for DM duration or severity. CONCLUSIONS AND LIMITATIONS The association between treatment for diabetes and dementia is differential according to drug class, which is potentially mediated by hypoglycemic risk. Not accounting for DM duration and/or severity is a major limitation in the available evidence base.
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Affiliation(s)
- Jacqueline M McMillan
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Bria S Mele
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - David B Hogan
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
| | - Alexander A Leung
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
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Abstract
Cognitive dysfunction is increasingly recognized as an important comorbidity of diabetes mellitus. Different stages of diabetes-associated cognitive dysfunction exist, each with different cognitive features, affected age groups and prognoses and probably with different underlying mechanisms. Relatively subtle, slowly progressive cognitive decrements occur in all age groups. More severe stages, particularly mild cognitive impairment and dementia, with progressive deficits, occur primarily in older individuals (>65 years of age). Patients in the latter group are the most relevant for patient management and are the focus of this Review. Here, we review the evolving insights from studies on risk factors, brain imaging and neuropathology, which provide important clues on mechanisms of both the subtle cognitive decrements and the more severe stages of cognitive dysfunction. In the majority of patients, the cognitive phenotype is probably defined by multiple aetiologies. Although both the risk of clinically diagnosed Alzheimer disease and that of vascular dementia is increased in association with diabetes, the cerebral burden of the prototypical pathologies of Alzheimer disease (such as neurofibrillary tangles and neuritic plaques) is not. A major challenge for researchers is to pinpoint from the spectrum of diabetes-related disease processes those that affect the brain and contribute to development of dementia beyond the pathologies of Alzheimer disease. Observations from experimental models can help to meet that challenge, but this requires further improving the synergy between experimental and clinical scientists. The development of targeted treatment and preventive strategies will therefore depend on these translational efforts.
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Affiliation(s)
- Geert Jan Biessels
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands.
| | - Florin Despa
- Department of Pharmacology and Nutritional Sciences and Department of Neurology, University of Kentucky, Lexington, KY, USA
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103
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Tseng CH. Pioglitazone Reduces Dementia Risk in Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Analysis. J Clin Med 2018; 7:E306. [PMID: 30262775 PMCID: PMC6209987 DOI: 10.3390/jcm7100306] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/20/2018] [Accepted: 09/23/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The beneficial effect of pioglitazone on dementia requires confirmation. METHODS The database of Taiwan's National Health Insurance was used to enroll a propensity score-matched-pair cohort of patients who had ever used pioglitazone and patients who had never used pioglitazone from Taiwanese patients with newly diagnosed diabetes mellitus during 1999⁻2008. The patients were to be alive on 1 January 2009 and were followed up for dementia until 31 December 2011. Hazard ratios were estimated using the Cox proportional hazards model. RESULTS There were 11,011 never users and 11,011 ever users of pioglitazone, with respective numbers of incident dementia of 123 and 91. The overall hazard ratio was 0.716 (95% confidence interval: 0.545⁻0.940) for ever users versus never users. The hazard ratios for the first (<11.0 months), second (11.0⁻19.6 months) and third (>19.6 months) tertiles of cumulative duration were 0.806 (0.544⁻1.193), 0.654 (0.430⁻0.994) and 0.694 (0.469⁻1.026), respectively. When cumulative duration was treated as a continuous variable, the hazard ratio was 0.987 (0.976⁻0.998). In subgroup analyses, the beneficial effect was mainly observed in patients who had not been treated with metformin. Among metformin ever users, the hazard ratio for dementia for pioglitazone ever users versus never users was 0.802 (0.580⁻1.109); and was 0.494 (0.284⁻0.857) among never users of metformin. No interaction between pioglitazone and major risk factors of dementia (i.e., stroke, hypoglycemia, head injury and Parkinson's disease) was observed. CONCLUSIONS Pioglitazone use is associated with a lower risk of dementia, especially when it is used in never users of metformin and has been used for more than 20 months.
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Affiliation(s)
- Chin-Hsiao Tseng
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan 350, Taiwan.
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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105
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Chen JL, Luo C, Pu D, Zhang GQ, Zhao YX, Sun Y, Zhao KX, Liao ZY, Lv AK, Zhu SY, Zhou J, Xiao Q. Metformin attenuates diabetes-induced tau hyperphosphorylation in vitro and in vivo by enhancing autophagic clearance. Exp Neurol 2018; 311:44-56. [PMID: 30219731 DOI: 10.1016/j.expneurol.2018.09.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 09/07/2018] [Accepted: 09/12/2018] [Indexed: 12/13/2022]
Abstract
Diabetes mellitus (DM) can increase the risk of Alzheimer's disease (AD) in patients. However, no effective approaches are available to prevent its progression and development. Recently, autophagy dysfunction was identified to be involved in the pathogenesis of neurodegenerative diseases. This study was designed to investigate the effect of metformin on hyperphosphorylated tau proteins in diabetic encephalopathy (DE) by regulating autophagy clearance. db/db mice were randomly divided into four groups, db/+ mice were used as control group. Twelve-week old male db/db mice received consecutive intraperitoneal injection of 200 mg/kg/d metformin or (and) 10 mg/kg/d chloroquine for eight weeks. Morris water maze (MWM) tests were performed to test cognitive functions before the mice were euthanized. Metformin attenuated cognitive impairment in db/db mice, reduced hyperphosphorylated tau proteins, restored the impaired autophagy in diabetic mice, all of which were reversed by inhibiting of autophagy activity. In high glucose-cultured HT22 cells, metformin increased autophagy in a dose-dependent manner. Besides, metformin enhanced autophagy activity in an AMPK dependent manner. These data show that metformin may reduce tauopathy and improve cognitive impairment in db/db mice by modulating autophagy through the AMPK dependent pathway. These findings highlight metformin as a new therapeutic strategy for the treatment of DE.
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Affiliation(s)
- Jin-Liang Chen
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Cheng Luo
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Die Pu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Guo-Qiang Zhang
- Department of Gastroenterology, Children's Hospital of Chongqing Medical University, No. 136, Zhongshan 2nd Road, 400014 Chongqing, China
| | - Yu-Xing Zhao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Yue Sun
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Ke-Xiang Zhao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Zhi-Yin Liao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - An-Kang Lv
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Shi-Yu Zhu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Jing Zhou
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Qian Xiao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China.
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Rotermund C, Machetanz G, Fitzgerald JC. The Therapeutic Potential of Metformin in Neurodegenerative Diseases. Front Endocrinol (Lausanne) 2018; 9:400. [PMID: 30072954 PMCID: PMC6060268 DOI: 10.3389/fendo.2018.00400] [Citation(s) in RCA: 188] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/27/2018] [Indexed: 12/12/2022] Open
Abstract
The search for treatments for neurodegenerative diseases is a major concern in light of today's aging population and an increasing burden on individuals, families, and society. Although great advances have been made in the last decades to understand the underlying genetic and biological cause of these diseases, only some symptomatic treatments are available. Metformin has long since been used to treat Type 2 Diabetes and has been shown to be beneficial in several other conditions. Metformin is well-tested in vitro and in vivo and an approved compound that targets diverse pathways including mitochondrial energy production and insulin signaling. There is growing evidence for the benefits of metformin to counteract age-related diseases such as cancer, cardiovascular disease, and neurodegenerative diseases. We will discuss evidence showing that certain neurodegenerative diseases and diabetes are explicitly linked and that metformin along with other diabetes drugs can reduce neurological symptoms in some patients and reduce disease phenotypes in animal and cell models. An interesting therapeutic factor might be how metformin is able to balance survival and death signaling in cells through pathways that are commonly associated with neurodegenerative diseases. In healthy neurons, these overarching signals keep energy metabolism, oxidative stress, and proteostasis in check, avoiding the dysfunction and neuronal death that defines neurodegenerative disease. We will discuss the biological mechanisms involved and the relevance of neuronal vulnerability and potential difficulties for future trials and development of therapies.
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Affiliation(s)
| | - Gerrit Machetanz
- Department of Neurodegenerative Diseases, Centre of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Julia C. Fitzgerald
- German Centre for Neurodegenerative Diseases, Tübingen, Germany
- Department of Neurodegenerative Diseases, Centre of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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107
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Rotermund C, Machetanz G, Fitzgerald JC. The Therapeutic Potential of Metformin in Neurodegenerative Diseases. Front Endocrinol (Lausanne) 2018; 9:400. [PMID: 30072954 DOI: 10.3389/fendo.2018.00400/xml/nlm] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/27/2018] [Indexed: 05/25/2023] Open
Abstract
The search for treatments for neurodegenerative diseases is a major concern in light of today's aging population and an increasing burden on individuals, families, and society. Although great advances have been made in the last decades to understand the underlying genetic and biological cause of these diseases, only some symptomatic treatments are available. Metformin has long since been used to treat Type 2 Diabetes and has been shown to be beneficial in several other conditions. Metformin is well-tested in vitro and in vivo and an approved compound that targets diverse pathways including mitochondrial energy production and insulin signaling. There is growing evidence for the benefits of metformin to counteract age-related diseases such as cancer, cardiovascular disease, and neurodegenerative diseases. We will discuss evidence showing that certain neurodegenerative diseases and diabetes are explicitly linked and that metformin along with other diabetes drugs can reduce neurological symptoms in some patients and reduce disease phenotypes in animal and cell models. An interesting therapeutic factor might be how metformin is able to balance survival and death signaling in cells through pathways that are commonly associated with neurodegenerative diseases. In healthy neurons, these overarching signals keep energy metabolism, oxidative stress, and proteostasis in check, avoiding the dysfunction and neuronal death that defines neurodegenerative disease. We will discuss the biological mechanisms involved and the relevance of neuronal vulnerability and potential difficulties for future trials and development of therapies.
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Affiliation(s)
| | - Gerrit Machetanz
- Department of Neurodegenerative Diseases, Centre of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Julia C Fitzgerald
- German Centre for Neurodegenerative Diseases, Tübingen, Germany
- Department of Neurodegenerative Diseases, Centre of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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