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Abstract
The traditional complications of diabetes mellitus are well known and continue to pose a considerable burden on millions of people living with diabetes mellitus. However, advances in the management of diabetes mellitus and, consequently, longer life expectancies, have resulted in the emergence of evidence of the existence of a different set of lesser-acknowledged diabetes mellitus complications. With declining mortality from vascular disease, which once accounted for more than 50% of deaths amongst people with diabetes mellitus, cancer and dementia now comprise the leading causes of death in people with diabetes mellitus in some countries or regions. Additionally, studies have demonstrated notable links between diabetes mellitus and a broad range of comorbidities, including cognitive decline, functional disability, affective disorders, obstructive sleep apnoea and liver disease, and have refined our understanding of the association between diabetes mellitus and infection. However, no published review currently synthesizes this evidence to provide an in-depth discussion of the burden and risks of these emerging complications. This Review summarizes information from systematic reviews and major cohort studies regarding emerging complications of type 1 and type 2 diabetes mellitus to identify and quantify associations, highlight gaps and discrepancies in the evidence, and consider implications for the future management of diabetes mellitus.
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Affiliation(s)
- Dunya Tomic
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jonathan E Shaw
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Dianna J Magliano
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
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Hadley G, Zhang J, Harris-Skillman E, Alexopoulou Z, DeLuca GC, Pendlebury ST. Cognitive decline and diabetes: a systematic review of the neuropathological correlates accounting for cognition at death. J Neurol Neurosurg Psychiatry 2022; 93:246-253. [PMID: 35086942 DOI: 10.1136/jnnp-2021-328158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/24/2021] [Indexed: 11/04/2022]
Abstract
Given conflicting findings in epidemiologic studies, we determined the relative contributions of different neuropathologies to the excess risk of cognitive decline in diabetes mellitus (DM) through a systematic review of the literature. Included studies compared subjects with and without DM and reported neuropathological outcomes accounting for cognition at death. Data on Alzheimer's disease (AD) pathology, cerebrovascular disease and non-vascular, non-AD pathology were extracted from each study. Eleven studies (n=6 prospective cohorts, n=5 retrospective post-mortem series, total n=6330) met inclusion criteria. All 11 studies quantified AD changes and 10/11 measured cerebrovascular disease: macroscopic lesions (n=9), microinfarcts (n=8), cerebral amyloid angiopathy (CAA, n=7), lacunes (n=6), white matter disease (n=5), haemorrhages (n=4), microbleeds (n=1), hippocampal microvasculature (n=1). Other pathology was infrequently examined. No study reported increased AD pathology in DM, three studies showed a decrease (n=872) and four (n= 4018) showed no difference, after adjustment for cognition at death. No study reported reduced cerebrovascular pathology in DM. Three studies (n=2345) reported an increase in large infarcts, lacunes and microinfarcts. One study found lower cognitive scores in DM compared to non-DM subjects despite similar cerebrovascular and AD-pathology load suggesting contributions from other neuropathological processes. In conclusion, lack of an association between DM and AD-related neuropathology was consistent across studies, irrespective of methodology. In contrast to AD, DM was associated with increased large and small vessel disease. Data on other pathologies such as non-AD neurodegeneration, and blood-brain-barrier breakdown were lacking. Further studies evaluating relative contributions of different neuropathologies to the excess risk of DM are needed.
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Affiliation(s)
- Gina Hadley
- Departments of General (internal) Medicine and Geratology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Jiali Zhang
- St Anne's College, University of Oxford, Oxford, UK
| | - Eva Harris-Skillman
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Gabriele C DeLuca
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK
| | - Sarah T Pendlebury
- Departments of General (internal) Medicine and Geratology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK .,NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK.,Wolfson Centre for Prevention of Stroke and Dementia, Wolfson Building, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Oghagbon EK, Prieto-Pino J, Dogoh F, Ogiator M, Giménez-Llort L. Diabetes/Dementia in Sub-saharian Africa and Nigerian Women in the Eye of Storm. Curr Alzheimer Res 2021; 19:161-170. [PMID: 34784865 DOI: 10.2174/1567205018666211116093747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/01/2021] [Accepted: 08/22/2021] [Indexed: 11/22/2022]
Abstract
In the next few years, the prevalence of diabetes mellitus (DM) is projected to dramatically increase globally, but most of the cases will occur in low-to-middle-income countries. Some of the major risk factors for diabetes accelerate the development of dementia in African-Americans, thus leading to a higher prevalence of dementia than Caucasians. Sub-Saharan Africa women have a disproportionately two-to-eight fold increased prevalence of dementia. In the eye of this storm, Nigeria holds the highest number of diabetics on the African continent, and its prevalence is rising in parallel to obesity, hypertension, and the population's aging. The socio-economic impact of the rising prevalence of DM and dementia will be huge and unsustainable for the healthcare system in Nigeria, as has been recognized in developed economies. Here, we analyze the current situation of women's health in Nigeria and explore future perspectives and directions. The complex interplay of factors involved in diabetes and dementia in Nigerian women include key biological agents (metabolic syndrome, vascular damage, inflammation, oxidative stress, insulin resistance), nutritional habits, lifestyle, and anemia, that worsen with comorbidities. In addition, restricted resources, lack of visibility, and poor management result in a painful chain that increases the risk and burden of disease in Nigerian women from youth to elderly ages. Heath policies to increase the ra- tio of mental health professionals per number of patients, mostly in rural areas, foment of proactive primary care centers, and interventions targeting adolescents and adult women and other specific mothers-children pairs are strongly required for a sustainable development goal.
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Affiliation(s)
- Efosa K Oghagbon
- Department of Chemical Pathology, Faculty of Basic & Allied Medical Sciences, College of Health Sciences, Benue State University, Makurdi. Nigeria
| | - José Prieto-Pino
- Department of Psychiatry and Forensic Medicine, Faculty of Medicine, Universitat Autònoma de Barcelona, Barcelona. Spain
| | - Faeren Dogoh
- Department of Chemical Pathology, Benue State University Teaching Hospital, Makurdi. Nigeria
| | - Monday Ogiator
- Department of Internal Medicine, Benue State University Teaching Hospital, Makurdi. Nigeria
| | - Lydia Giménez-Llort
- Department of Psychiatry and Forensic Medicine, Faculty of Medicine, Universitat Autònoma de Barcelona, Barcelona. Spain
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Ismail AA, Alghasham NS, Alsukhaiber RE, Alnowiasser FM. Dementia screening of geriatric patients by implementing an informant-based Alzheimer's disease eight-item tool in KSA. J Taibah Univ Med Sci 2021; 16:191-197. [PMID: 33897323 PMCID: PMC8046828 DOI: 10.1016/j.jtumed.2020.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 11/29/2022] Open
Abstract
Objectives The screening of dementia among geriatrics is necessary to identify probable cases, confirm diagnosis, institute treatment, and plan for future family caregiving strategies. This study aimed to screen the incidence of dementia among geriatric patients using the informant-based Alzheimer's disease eight-item tool for dementia (AD8) in a KSA region. Methods A cross-sectional study was conducted among geriatric patients in the KSA region at selected hospitals from December 2019 to March 2020. The caregivers of 100 geriatric patients were interviewed using the AD8. Results Among the 100 patients, 43% were 65–75 years old, 52% were men, and 48% were women, mean age was (78) for both genders. Diabetes mellitus was the most reported chronic illness, found in 68% of the patients, followed by a history of cerebrovascular disease (52%). Loss of more than four but less than half of the teeth was reported in 41% of the patients, while 10% were reported to be undergoing polypharmacy. Dementia was diagnosed in 74% of patients and had a statistically significant association with a history of stroke (p < 0.001), number of teeth lost (p = 0.02), and number of drugs administered (p = 0.006). A binary logistic regression model fitted to predict dementia based on the effect of a stroke history, number of missing teeth, and number of drugs administered showed that patients with stroke were 1.43 (95% CI 1.4–4.2) times likely to develop dementia than those with no history of stroke. Conclusion Cases of dementia are frequent among geriatric patients in the Qassim region of KSA. A dementia positive screening is correlated with a history of stroke, number of lost teeth, polypharmacy, and age. Stroke prevention and early treatment can potentially reduce the likelihood of dementia occurrence.
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Affiliation(s)
- Amal A Ismail
- Department of Pharmacy Practice, Unaizah College of Pharmacy, Qassim University, Unaizah, KSA
| | - Nada S Alghasham
- Department of Pharmacy Practice, Unaizah College of Pharmacy, Qassim University, Unaizah, KSA
| | - Rawan E Alsukhaiber
- Department of Pharmacy Practice, Unaizah College of Pharmacy, Qassim University, Unaizah, KSA
| | - Fatimah M Alnowiasser
- Department of Pharmacy Practice, Unaizah College of Pharmacy, Qassim University, Unaizah, KSA
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Hendrix RD, Ou Y, Davis JE, Odle AK, Groves TR, Allen AR, Childs GV, Barger SW. Alzheimer amyloid-β- peptide disrupts membrane localization of glucose transporter 1 in astrocytes: implications for glucose levels in brain and blood. Neurobiol Aging 2020; 97:73-88. [PMID: 33161213 PMCID: PMC7736209 DOI: 10.1016/j.neurobiolaging.2020.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/25/2020] [Accepted: 10/02/2020] [Indexed: 12/12/2022]
Abstract
Alzheimer’s disease (AD) is associated with disturbances in blood glucose regulation, and type-2 diabetes elevates the risk for dementia. A role for amyloid-β peptide (Aβ) in linking these age-related conditions has been proposed, tested primarily in transgenic mouse lines that overexpress mutated amyloid precursor protein (APP). Because APP has its own impacts on glucose regulation, we examined the BRI-Aβ42 line (“Aβ42-tg”), which produces extracellular Aβ1–42 in the CNS without elevation of APP. We also looked for interactions with diet-induced obesity (DIO) resulting from a high-fat, high-sucrose (“western”) diet. Aβ42-tg mice were impaired in both spatial memory and glucose tolerance. Although DIO induced insulin resistance, Aβ1–42 accumulation did not, and the impacts of DIO and Aβ on glucose tolerance were merely additive. Aβ42-tg mice exhibited no significant differences from wild-type in insulin production, body weight, lipidemia, appetite, physical activity, respiratory quotient, an-/orexigenic factors, or inflammatory factors. These negative findings suggested that the phenotype in these mice arose from perturbation of glucose excursion in an insulin-independent tissue. To wit, cerebral cortex of Aβ42-tg mice had reduced glucose utilization, similar to human patients with AD. This was associated with insufficient trafficking of glucose transporter 1 to the plasma membrane in parenchymal brain cells, a finding also documented in human AD tissue. Together, the lower cerebral metabolic rate of glucose and diminished function of parenchymal glucose transporter 1 indicate that aberrant regulation of blood glucose in AD likely reflects a central phenomenon, resulting from the effects of Aβ on cerebral parenchyma, rather than a generalized disruption of hypothalamic or peripheral endocrinology. The involvement of a specific glucose transporter in this deficit provides a new target for the design of AD therapies.
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Affiliation(s)
- Rachel D Hendrix
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Yang Ou
- Department of Geriatrics, Little Rock, AR, USA
| | - Jakeira E Davis
- Graduate Program in Interdisciplinary Biomedical Sciences, Little Rock, AR, USA
| | - Angela K Odle
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Thomas R Groves
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Antiño R Allen
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gwen V Childs
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Steven W Barger
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA; Department of Geriatrics, Little Rock, AR, USA; Geriatric Research, Education & Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR, USA.
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Mild Cognitive Impairment Subtypes and Type 2 Diabetes in Elderly Subjects. J Clin Med 2020; 9:jcm9072055. [PMID: 32629878 PMCID: PMC7408775 DOI: 10.3390/jcm9072055] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/09/2020] [Accepted: 06/24/2020] [Indexed: 01/02/2023] Open
Abstract
Background: Type 2 diabetes (T2D) is correlated to amnestic mild cognitive impairment (aMCI) and to non-amnestic mild cognitive impairment (naMCI). This study evaluated whether the T2D variable characterizes a peculiar cognitive profile in elderly patients. Moreover, it explores the association between glycated hemoglobin levels (HbA1c), T2D duration, insulin and oral hypoglycemic agent treatment, and cognition in elderly diabetic patients. Methods: Detailed neuropsychological battery was used to diagnose MCI subtypes. A total of 39 MCI subjects with T2D (T2D-MCI) and 37 MCI subjects without T2D (ND-MCI), matched for age, educational level, and Mini-Mental State Examination score, were included. Results: ND-MCI performed worse in memory and language domains than T2D-MCI. The amnestic subtype is more frequent among ND-MCI and non-amnestic subtype in T2D-MCI. In T2D-MCI, high HbA1c levels correlate with episodic memory (immediate recall) and T2D duration. Some indexes of episodic memory (immediate recall), attention, and visual-spatial ability correlate with insulin treatment. Conclusions: An association between T2D and non-amnestic MCI is suggested. In the T2D-MCI group, significant associations between insulin treatment and memory (immediate recall), complex figure copy, and attention were found.
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Liu W, Zhou Y, Liang R, Zhang Y. Inhibition of cyclin-dependent kinase 5 activity alleviates diabetes-related cognitive deficits. FASEB J 2019; 33:14506-14515. [PMID: 31689375 DOI: 10.1096/fj.201901292r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cognitive deficit is a prevalent and underestimated complication of diabetes, and the underlying cellular and molecular mechanisms are not well understood. Aberrant activity of cyclin-dependent kinase (Cdk)5 is implicated in a number of neurodegenerative diseases. The present study examined the role of Cdk5 in the progression of diabetes-related cognitive deficits. We showed that the Cdk5 protein expression and kinase activity were significantly increased in diabetic mice at 16 wk. In primary cultured hippocampal neurons exposed to 30 mM glucose, Cdk5 protein and kinase activity were also elevated in a time-dependent manner. Moreover, the high glucose exposure led to an aberrant Cdk5 activation due to its activator p25 that was cleaved from p35 by calpain. Both in diabetic mice and in cultured hippocampal neurons exposed to high glucose, inhibition of Cdk5 activity with roscovitine (Ros) or short hairpin RNA (shRNA) decreased the protein levels of cleaved caspase-3 and the ratio of Bax and Bcl-2. The apoptotic rate detected by TUNEL in vivo or Annexin V and propidium iodide staining for flow cytometry in vitro also had obvious reduction. In addition, high glucose exposure resulted in the increase of phosphorylated (phospho)-MAPK kinase (MKK)6, phospho-p38, and c-Jun, which were rescued by Ros or Cdk5 shRNA. It is more important that the cognitive deficits of diabetic mice were also effectively alleviated by Ros. These results indicate that aberrant Cdk5 activity triggered hippocampal neuron apoptosis by activating MKK6/p38 MAPK cascade in hyperglycemia. Inhibition of Cdk5 overactivation attenuates neuronal apoptosis and cognitive deficits and contributes to the relief of diabetic neurotoxicity in the brain.-Liu, W., Zhou, Y., Liang, R., Zhang, Y. Inhibition of cyclin-dependent kinase 5 activity alleviates diabetes-related cognitive deficits.
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Affiliation(s)
- Wei Liu
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Yi Zhou
- Department of Neurology, The Second Hospital of Hebei Medical University, Hebei Medical University, Shijiazhuang, China
| | - Rui Liang
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Yue Zhang
- Department of Clinical Diagnostics, Hebei Medical University, Shijiazhuang, China
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Bhusal A, Rahman MH, Lee WH, Bae YC, Lee IK, Suk K. Paradoxical role of lipocalin-2 in metabolic disorders and neurological complications. Biochem Pharmacol 2019; 169:113626. [PMID: 31476294 DOI: 10.1016/j.bcp.2019.113626] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/28/2019] [Indexed: 02/07/2023]
Abstract
Lipocalin-2 (LCN2), also known as 24p3 and neutrophil gelatinase-associated lipocalin (NGAL), is a 25-kDa secreted protein implicated in various metabolic and inflammatory diseases. Early studies suggest the protective function of LCN2 in which it acts as a bacteriostatic agent that competes with bacteria for iron-bound siderophores. However, both detrimental and beneficial roles of LCN2 have recently been documented in metabolic and neuroinflammatory diseases. Metabolic inflammation, as observed in diabetes and obesity, has been closely associated with the upregulation of LCN2 in blood plasma and several tissues in both humans and rodents, suggesting its pro-diabetic and pro-obesogenic role. On the contrary, other studies imply an anti-diabetic and anti-obesogenic role of LCN2 whereby a deficiency in the Lcn2 gene results in the impairment of insulin sensitivity and enhances the high-fat-diet-induced expansion of fat. A similar dual role of LCN2 has also been reported in various animal models for neurological disorders. In the midst of these mixed findings, there is no experimental evidence to explain why LCN2 shows such a contrasting role in the various studies. This debate needs to be resolved (or reconciled) and an integrated view on the topic is desirable. Herein, we attempt to address this issue by reviewing the recent findings on LCN2 in metabolic disorders and assess the potential cellular or molecular mechanisms underlying the dual role of LCN2. We further discuss the possibilities and challenges of targeting LCN2 as a potential therapeutic strategy for metabolic disorders and neurological complications.
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Affiliation(s)
- Anup Bhusal
- Department of Pharmacology, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; Department of Biomedical Science, BK21 PLUS KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Pharmacology, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; Department of Biomedical Science, BK21 PLUS KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Won-Ha Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; Department of Biomedical Science, BK21 PLUS KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
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Oghagbon EK, Giménez-Llort L. Short height and poor education increase the risk of dementia in Nigerian type 2 diabetic women. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2019; 11:493-499. [PMID: 31334329 PMCID: PMC6624244 DOI: 10.1016/j.dadm.2019.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Introduction There is urgent need to investigate type 2 diabetes and dementia crosstalk in sub-Saharan African countries with special attention to women who have higher vulnerability. Nigeria which has the highest number of diabetics on the African continent is a good location for the investigation. Methods Biophysical parameters, occupation, education, burden of diabetes mellitus, cardiovascular health, and cognition were evaluated in 102 type 2 diabetics and 99 controls. Results Short physical stature and lower level of education were hallmarks of diabetes in females. Two dementia scales (Mini–Mental State Examination and six-item Cognitive Impairment Test) showed cognitive impairment status, with the six-item Cognitive Impairment Test scale being more specific and sensitive. Both scales showed correlations with age, education, weight, height, and disease onset, whereas fasten blood glucose was negatively correlated with height and their blood pressure was normal. Discussion Height, an easy-to-measure parameter in Nigeria, may reveal increased risk of dementia in poorly educated female Nigerian diabetics, thus helping to improve preventive and therapeutic interventions.
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Affiliation(s)
- Efosa Kenneth Oghagbon
- Faculty of Basic & Allied Medical Sciences, Department of Chemical Pathology, College of Health Sciences, Benue State University, Makurdi, Nigeria
- Department of Chemical Pathology, Benue State University Teaching Hospital, Makurdi, Nigeria
| | - Lydia Giménez-Llort
- Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- Corresponding author. Tel: +34-5812378; Fax: +34-935811435.
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Chornenkyy Y, Wang W, Wei A, Nelson PT. Alzheimer's disease and type 2 diabetes mellitus are distinct diseases with potential overlapping metabolic dysfunction upstream of observed cognitive decline. Brain Pathol 2019; 29:3-17. [PMID: 30106209 PMCID: PMC6427919 DOI: 10.1111/bpa.12655] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 08/09/2018] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are highly prevalent aging-related diseases associated with significant morbidity and mortality. Some findings in human and animal models have linked T2DM to AD-type dementia. Despite epidemiological associations between the T2DM and cognitive impairment, the interrelational mechanisms are unclear. The preponderance of evidence in longitudinal studies with autopsy confirmation have indicated that vascular mechanisms, rather than classic AD-type pathologies, underlie the cognitive decline often seen in self-reported T2DM. T2DM is associated with cardiovascular and cerebrovascular disease (CVD), and is associated with increased risk of infarcts and small vessel disease in the brain and other organs. Neuropathological examinations of post-mortem brains demonstrated evidence of cerebrovascular disease and little to no correlation between T2DM and β-amyloid deposits or neurofibrillary tangles. Nevertheless, the mechanisms upstream of early AD-specific pathology remain obscure. In this regard, there may indeed be overlap between the pathologic mechanisms of T2DM/"metabolic syndrome," and AD. More specifically, cerebral insulin processing, glucose metabolism, mitochondrial function, and/or lipid metabolism could be altered in patients in early AD and directly influence symptomatology and/or neuropathology.
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Affiliation(s)
| | - Wang‐Xia Wang
- University of Kentucky College of MedicineLexingtonKY
- Sanders‐Brown Center on Aging, Department of PathologyUniversity of KentuckyLexingtonKY
| | - Angela Wei
- Department of BiologyUniversity of KentuckyLexingtonKY
| | - Peter T. Nelson
- University of Kentucky College of MedicineLexingtonKY
- Sanders‐Brown Center on Aging, Department of PathologyUniversity of KentuckyLexingtonKY
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Kulas JA, Franklin WF, Smith NA, Manocha GD, Puig KL, Nagamoto-Combs K, Hendrix RD, Taglialatela G, Barger SW, Combs CK. Ablation of amyloid precursor protein increases insulin-degrading enzyme levels and activity in brain and peripheral tissues. Am J Physiol Endocrinol Metab 2019; 316:E106-E120. [PMID: 30422705 PMCID: PMC6417684 DOI: 10.1152/ajpendo.00279.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The amyloid precursor protein (APP) is a type I transmembrane glycoprotein widely studied for its role as the source of β-amyloid peptide, accumulation of which is causal in at least some cases of Alzheimer's disease (AD). APP is expressed ubiquitously and is involved in diverse biological processes. Growing bodies of evidence indicate connections between AD and somatic metabolic disorders related to type 2 diabetes, and App-/- mice show alterations in glycemic regulation. We find that App-/- mice have higher levels of insulin-degrading enzyme (IDE) mRNA, protein, and activity compared with wild-type controls. This regulation of IDE by APP was widespread across numerous tissues, including liver, skeletal muscle, and brain as well as cell types within neural tissue, including neurons, astrocytes, and microglia. RNA interference-mediated knockdown of APP in the SIM-A9 microglia cell line elevated IDE levels. Fasting levels of blood insulin were lower in App-/- than App+/+ mice, but the former showed a larger increase in response to glucose. These low basal levels may enhance peripheral insulin sensitivity, as App-/- mice failed to develop impairment of glucose tolerance on a high-fat, high-sucrose ("Western") diet. Insulin levels and insulin signaling were also lower in the App-/- brain; synaptosomes prepared from App-/- hippocampus showed diminished insulin receptor phosphorylation compared with App+/+ mice when stimulated ex vivo. These findings represent a new molecular link connecting APP to metabolic homeostasis and demonstrate a novel role for APP as an upstream regulator of IDE in vivo.
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Affiliation(s)
- Joshua A Kulas
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Whitney F Franklin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch , Galveston, Texas
| | - Nicholas A Smith
- Department of Pathology, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Gunjan D Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Kendra L Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Kumi Nagamoto-Combs
- Department of Pathology, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Rachel D Hendrix
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences , Little Rock Arkansas
| | - Giulio Taglialatela
- Department of Neurology, University of Texas Medical Branch , Galveston, Texas
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences , Little Rock Arkansas
- Geriatric Research, Education and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
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Maternal Cognitive Impairment Associated with Gestational Diabetes Mellitus-A Review of Potential Contributing Mechanisms. Int J Mol Sci 2018; 19:ijms19123894. [PMID: 30563117 PMCID: PMC6321050 DOI: 10.3390/ijms19123894] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 11/14/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022] Open
Abstract
Gestational diabetes mellitus (GDM) carries many risks, where high blood pressure, preeclampsia and future type II diabetes are widely acknowledged, but less focus has been placed on its effect on cognitive function. Although the multifactorial pathogenesis of maternal cognitive impairment is not completely understood, it shares several features with type 2 diabetes mellitus (T2DM). In this review, we discuss some key pathophysiologies of GDM that may lead to cognitive impairment, specifically hyperglycemia, insulin resistance, oxidative stress, and neuroinflammation. We explain how these incidents: (i) impair the insulin-signaling pathway and/or (ii) lead to cognitive impairment through hyperphosphorylation of τ protein, overexpression of amyloid-β and/or activation of microglia. The aforementioned pathologies impair the insulin-signaling pathway primarily through serine phosphorylation of insulin receptor substances (IRS). This then leads to the inactivation of the phosphatidylinositol 3-kinase/Protein kinase B (PI3K/AKT) signaling cascade, which is responsible for maintaining brain homeostasis and normal cognitive functioning. PI3K/AKT is crucial in maintaining normal cognitive function through the inactivation of glycogen synthase kinase 3β (GSκ3β), which hyperphosphorylates τ protein and releases pro-inflammatory cytokines that are neurotoxic. Several biomarkers were also highlighted as potential biomarkers of GDM-related cognitive impairment such as AGEs, serine-phosphorylated IRS-1 and inflammatory markers such as tumor necrosis factor α (TNF-α), high-sensitivity C-reactive protein (hs-CRP), leptin, interleukin 1β (IL-1β), and IL-6. Although GDM is a transient disease, its complications may be long-term, and hence increased mechanistic knowledge of the molecular changes contributing to cognitive impairment may provide important clues for interventional strategies.
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