Diabetes and the brain: issues and unmet needs

Prevalence of Cognitive Impairment and Associated Factors Among Diabetes Mellitus Patients Attending Follow-up Treatment at Fiche General Hospital, North Ethiopia

Introduction

Cognitive impairment is having trouble remembering, learning new things, concentrating, or making decisions that affect the daily life of diabetic patients. The worldwide prevalence of diabetes mellitus (DM) was 2.8% in 2000 and is estimated to be 4.4% by 2030.

Objective

To assess the prevalence of cognitive impairment and associated factors among DM patients attending follow-up treatment at Fiche General Hospital, North Ethiopia, 2022.

Methods

A hospital-based cross-sectional study was conducted from July 15 to September 15, 2022. The total sample size was 421 and a systematic random sampling technique was used. Data were collected through a face-to-face interview. Data were entered using EpiData Version 3.1 and exported to SPSS Version 24 for analysis. Statistically significant was declared at a P-value of less than .05 with an adjusted odds ratio (AOR) and 95% confidence interval (CI).

Result

The prevalence of cognitive impairment in the current study was 56.3% with (95% CI: 51.5-60.8). Primary educational status (AOR 6.73, 95% CI: 2.92-15.51), having Type II DM (AOR 4.93, 95% CI: 2.84-8.56), uncontrolled blood sugar (AOR 6.24, 95% CI: 3.84-10.17), and current alcohol use (AOR 1.94, 95% CI: 1.11-3.36) were significantly associated.

Conclusion

About three in 5 DM patients attending follow-up treatment at Fiche General Hospital were suffering from cognitive impairment. Educational status, type of DM, status of fasting blood sugar, and current alcohol use were associated with cognitive impairment among DM patients. Therefore, improving educational status, controlling blood sugar, and avoiding alcohol use may reduce the risk of cognitive impairment in DM patients.

Self-Reported Executive Function in Hospitalized Cardiac Patients and Associations With Patient Characteristics and Cardiac Rehabilitation Attendance

PURPOSE

Executive function (ExF), the ability to do complex cognitive tasks like planning and refraining from impulsive behavior, is associated with compliance with medical recommendations. The present study identified associations between self-reported ExF and demographics of patients with cardiac disease as well as with cardiac rehabilitation (CR) attendance.

METHODS

Self-reported ExF impairment was measured using the Behavior Rating Inventory of Executive Function (BRIEF) on 316 individuals hospitalized for CR-qualifying cardiac events. Scores were calculated for a global measure (Global Executive Composite [GEC]) and the two BRIEF indices: Behavioral Regulation Index and Metacognition Index (MCI). Participants were followed up post-discharge to determine CR attendance. Univariate logistic regressions between ExF measures and demographic variables were conducted, as were multiple logistic regressions to identify significant, independent predictors. Analyses were conducted using clinical (T scores ≥ 65) and subclinical (T scores ≥ 60) criteria for significant ExF impairment as outcomes. One-way analyses of variance were performed between ExF impairment and CR attendance.

RESULTS

Self-reported ExF deficits were relatively rare; 8.9% had at least subclinical scores on the GEC. Using the subclinical criterion for the MCI, having diabetes mellitus (DM) and being male were significant, independent predictors of MCI impairment. No significant relationship was found between ExF and CR attendance.

CONCLUSION

Using the subclinical criterion only, individuals with DM and males were significantly more likely to have MCI impairment. No significant effect of ExF impairment on CR attendance was found, suggesting that self-reported ExF measured in the hospital may not be an appropriate measure for predicting behavioral outcomes.

Effects of Fibroblast Growth Factor 21 on Lactate Uptake and Usage in Mice with Diabetes-Associated Cognitive Decline

Fibroblast growth factor 21 (FGF21) is an endocrine hormone that exerts beneficial effects on glucose and lipid metabolic homeostasis. However, the impact of FGF21 on type 1 diabetes-associated cognitive decline (DACD) and its mechanisms of action remain unclear. In this study, we aimed to evaluate the effects of FGF21 on lactate uptake and usage in a mouse model of streptozotocin-induced DACD. Six-week-old male C57BL/6 mice were divided into the control, diabetic, and FGF21 (which received 2 mg/kg recombinant human FGF21) groups. At the end of the treatment period, learning and memory performance, nuclear magnetic resonance-based metabonomics, and expressions of various hippocampal protein were analyzed to determine the efficacy of FGF21. The results showed that compared to the control mice, the diabetic mice had reduced long-term memory performance after the hyperglycemic insult; decreased hippocampal levels of lactate dehydrogenase-B (LDH-B) activity, bioenergy metabolites, and monocarboxylate transporter 2 (MCT2); and increased lactate levels. Impaired phosphoinositide 3-kinase (PI3K) signaling was also observed in the diabetic mice. However, FGF21 treatment improved LDH-B activity, β-nicotinamide adenine dinucleotide, and ATP levels, and increased MCT2 expression and PI3K signaling pathway, which in turn improved the learning and memory defects. These findings demonstrated that the effects of FGF21 on DACD were associated with its ability to improve LDH-B-mediated lactate usage and MCT2-dependent lactate uptake. Further, these beneficial effects of FGF21 in the hippocampus were mediated by the PI3K signaling pathways.

Heterogeneity in Alzheimer's Disease Diagnosis and Progression Rates: Implications for Therapeutic Trials

The clinical presentation and the pathological processes underlying Alzheimer's disease (AD) can be very heterogeneous in severity, location, and composition including the amount and distribution of AB deposition and spread of neurofibrillary tangles in different brain regions resulting in atypical clinical patterns and the existence of distinct AD variants. Heterogeneity in AD may be related to demographic factors (such as age, sex, educational and socioeconomic level) and genetic factors, which influence underlying pathology, the cognitive and behavioral phenotype, rate of progression, the occurrence of neuropsychiatric features, and the presence of comorbidities (e.g., vascular disease, neuroinflammation). Heterogeneity is also manifest in the individual resilience to the development of neuropathology (brain reserve) and the ability to compensate for its cognitive and functional impact (cognitive and functional reserve). The variability in specific cognitive profiles and types of functional impairment may be associated with different progression rates, and standard measures assessing progression may not be equivalent for individual cognitive and functional profiles. Other factors, which may govern the presence, rate, and type of progression of AD, include the individuals' general medical health, the presence of specific systemic conditions, and lifestyle factors, including physical exercise, cognitive and social stimulation, amount of leisure activities, environmental stressors, such as toxins and pollution, and the effects of medications used to treat medical and behavioral conditions. These factors that affect progression are important to consider while designing a clinical trial to ensure, as far as possible, well-balanced treatment and control groups.

Effects of berberine on cholinesterases and monoamine oxidase activities, and antioxidant status in the brain of streptozotocin (STZ)-induced diabetic rats

OBJECTIVES

Several studies had been conducted to examine the link between diabetes and diabetes encephalopathy. This study was conducted to examine the potency of berberine (BER) on the restoration of impaired neurochemicals in the brain of streptozotocin (STZ)-induced diabetic Wistar rats.

METHODS

Fifty-six (56) adult rats weighing between 200 and 230 g were randomly divided into seven groups (n=8) as follows; Group I is normal control; Groups II and III were normal rats treated with 50 and 100 mg/kg respectively; Group IV-VII were STZ-induced rats, but Groups V-VII were treated with acarbose (25 mg/kg), 50 and 100 mg/kg of BER, respectively.

RESULTS

The result of the study showed that untreated STZ-induced diabetic rats have increased acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO) activities, and malonylaldehyde (MDA) level, with concomitant decrease of superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, and glutathione (GSH) level. However, daily treatment with 50 and 100 mg/kg BER and ACA significantly reversed these effects.

CONCLUSIONS

The findings of this study clearly indicated that BER possesses neuro-protective and antioxidative potentials and normalize neurochemical impairment distort by diabetes.

Oxymatrine Ameliorates Memory Impairment in Diabetic Rats by Regulating Oxidative Stress and Apoptosis: Involvement of NOX2/NOX4

Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait and has been shown to exhibit a diverse range of pharmacological properties. The aim of the present study was to investigate the role of OMT in diabetic brain injury in vivo and in vitro. Diabetic rats were induced by intraperitoneal injection of a single dose of 65 mg/kg streptozotocin (STZ) and fed a high-fat and high-cholesterol diet. Memory function was assessed using a Morris water maze test. A SH-SY5Y cell injury model was induced by incubation with glucose (30 mM/l) to simulate damage in vitro. The serum fasting blood glucose, insulin, serum S100B, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were analyzed using commercial kits. Morphological changes were observed using Nissl staining and electron microscopy. Cell apoptosis was assessed using Hoechst staining and TUNEL staining. NADPH oxidase (NOX) and caspase-3 activities were determined. The effects of NOX2 and NOX4 knockdown were assessed using small interfering RNA. The expression levels of NOX1, NOX2, and NOX4 were detected using reverse transcription-quantitative PCR and western blotting, and the levels of caspase-3 were detected using western blotting. The diabetic rats exhibited significantly increased plasma glucose, insulin, reactive oxygen species (ROS), S-100B, and MDA levels and decreased SOD levels. Memory function was determined by assessing the percentage of time spent in the target quadrant, the number of times the platform was crossed, escape latency, and mean path length and was found to be significantly reduced in the diabetic rats. Hyperglycemia resulted in notable brain injury, including histological changes and apoptosis in the cortex and hippocampus. The expression levels of NOX2 and NOX4 were significantly upregulated at the protein and mRNA levels, and NOX1 expression was not altered in the diabetic rats. NOX and caspase-3 activities were increased, and caspase-3 expression was upregulated in the brain tissue of diabetic rats. OMT treatment dose-dependently reversed behavioral, biochemical, and molecular changes in the diabetic rats. In vitro, high glucose resulted in increases in reactive oxygen species (ROS), MDA levels, apoptosis, and the expressions of NOX2, NOX4, and caspase-3. siRNA-mediated knockdown of NOX2 and NOX4 decreased NOX2 and NOX4 expression levels, respectively, and reduced ROS levels and apoptosis. The results of the present study suggest that OMT alleviates diabetes-associated cognitive decline, oxidative stress, and apoptosis via NOX2 and NOX4 inhibition.

Brain Endothelial Cells Regulate Glucagon-Like Peptide 1 Entry Into the Brain via a Receptor-Mediated Process

Glucagon-like peptide 1 (GLP-1) in addition to regulating glucose-dependent insulin and glucagon secretion exerts anorexic and neuroprotective effects. While brain-derived GLP-1 may participate in these central actions, evidence suggests that peripherally derived GLP-1 plays an important role and GLP-1 analogs are known to cross the blood brain barrier. To define the role of brain microvascular endothelial cells in GLP-1 entry into the brain, we infused labeled GLP-1 or exendin-4 into rats intravenously and examined their appearance and protein kinase A activities in various brain regions. We also studied the role of endothelial cell GLP-1 receptor and its signaling in endothelial cell uptake and transport of GLP-1. Systemically infused labeled GLP-1 or exendin-4 appeared rapidly in various brain regions and this was associated with increased protein kinase A activity in these brain regions. Pretreatment with GLP-1 receptor antagonist reduced labeled GLP-1 or exendin-4 enrichment in the brain. Sub-diaphragmatic vagus nerve resection did not alter GLP-1-mediated increases in protein kinase A activity in the brain. Rat brain microvascular endothelial cells rapidly took up labeled GLP-1 and this was blunted by either GLP-1 receptor antagonism or protein kinase A inhibition but enhanced through adenylyl cyclase activation. Using an artificially assembled blood brain barrier consisting of endothelial and astrocyte layers, we found that labeled GLP-1 time-dependently crossed the barrier and the presence of GLP-1 receptor antagonist blunted this transit. We conclude that GLP-1 crosses the blood brain barrier through active trans-endothelial transport which requires GLP-1 receptor binding and activation.

Current Synthesis and Systematic Review of Main Effects of Calf Blood Deproteinized Medicine (Actovegin®) in Ischemic Stroke

Background: Stroke is one of the largest problems and clinical-social challenges within neurology and, in general, pathology. Here, we briefly reviewed the main pathophysiological mechanisms of ischemic stroke, which represent targets for medical interventions, including for a calf blood deproteinized hemodialysate/ultrafiltrate. Methods: We conducted a systematic review of current related literature concerning the effects of Actovegin^®, of mainly the pleiotropic type, applied to the injury pathways of ischemic stroke. Results: The bibliographic resources regarding the use of Actovegin^® in ischemic stroke are scarce. The main Actovegin^® actions refer to the ischemic stroke lesion items’ ensemble, targeting tissue oxidation, energy metabolism, and glucose availability through their augmentation, combating ischemic processes and oxidative stress, and decreasing inflammation (including with modulatory connotations, by the nuclear factor-κB pathway) and apoptosis-like processes, counteracting them by mitigating the caspase-3 activation induced by amyloid β-peptides. Conclusion: Since no available therapeutic agents are capable of curing the central nervous system’s lesions, any contribution, such as that of Actovegin^® (with consideration of a positive balance between benefits and risks), is worthy of further study and periodic reappraisal, including investigation into further connected aspects.

Cognitive impairment before and after intracerebral haemorrhage: a systematic review

INTRODUCTION

There is increasing interest in understanding cognitive dysfunction before and after Intracerebral haemorrhage (ICH), given the higher prevalence of dementia reported (ranging from 5 to 44%) for this stroke type. Much of the evidence to date examining cognitive impairment associated with cerebrovascular disease has tended to focus more on ischaemic stroke. The aim of this review was to identify and quantify studies that focused on cognitive dysfunction pre and post ICH.

METHODS

We conducted a systematic search using databases PubMed, Science Direct, Scopus and PsycINFO to identify studies that exclusively assessed cognitive function pre and post ICH. Studies were included in the review if used a measure of global cognition and/or a neuropsychological battery to assess cognitive function. Nineteen studies were deemed relevant for inclusion, where n = 8 studies examined cognitive impairment pre ICH and n = 11 post ICH.

RESULTS

Prevalence of cognitive impairment ranged between 9-29% for pre ICH and 14-88% for post ICH. Predictive factors identified for pre and post ICH were previous stroke, ICH volume and location and markers of cerebral amyloid angiopathy (CAA). Most common cognitive domains affected post ICH were information processing speed, executive function, memory, language and visuo-spatial abilities. Most common cognitive assessments tools were the Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) for pre-existing cognitive impairment and the Mini-Mental State Examination for global cognition post ICH and the Trail Making Test where neuropsychological tests were used.

CONCLUSION

Cognitive impairment and dementia affected almost one-third of patients, whether assessed pre or post ICH.

Hidden heterogeneity in Alzheimer's disease: Insights from genetic association studies and other analyses

Despite evident success in clarifying many important features of Alzheimer's disease (AD) the efficient methods of its prevention and treatment are not yet available. The reasons are likely to be the fact that AD is a multifactorial and heterogeneous health disorder with multiple alternative pathways of disease development and progression. The availability of genetic data on individuals participated in longitudinal studies of aging health and longevity, as well as on participants of cross-sectional case-control studies allow for investigating genetic and non-genetic connections with AD and to link the results of these analyses with research findings obtained in clinical, experimental, and molecular biological studies of this health disorder. The objective of this paper is to perform GWAS of AD in several study populations and investigate possible roles of detected genetic factors in developing AD hallmarks and in other health disorders. The data collected in the Framingham Heart Study (FHS), Cardiovascular Health Study (CHS), Health and Retirement Study (HRS) and Late Onset Alzheimer's Disease Family Study (LOADFS) were used in these analyses. The logistic regression and Cox's regression were used as statistical models in GWAS. The results of analyses confirmed strong associations of genetic variants from well-known genes APOE, TOMM40, PVRL2 (NECTIN2), and APOC1 with AD. Possible roles of these genes in pathological mechanisms resulting in development of hallmarks of AD are described. Many genes whose connection with AD was detected in other studies showed nominally significant associations with this health disorder in our study. The evidence on genetic connections between AD and vulnerability to infection, as well as between AD and other health disorders, such as cancer and type 2 diabetes, were investigated. The progress in uncovering hidden heterogeneity in AD would be substantially facilitated if common mechanisms involved in development of AD, its hallmarks, and AD related chronic conditions were investigated in their mutual connection.

Interaction Between Midlife Blood Glucose and APOE Genotype Predicts Later Alzheimer's Disease Pathology

Elevated blood glucose and the apolipoprotein (APOE) ɛ4 allele have both been associated with increased dementia risk; however, the neuropathological mechanisms underlying these associations remain unclear. We examined the impact of APOE genotype and midlife blood glucose on post-mortem vascular and Alzheimer's disease (AD) neuropathology. Ninety-four participants from the Framingham Heart Study without diagnosed diabetes underwent health examination at midlife and brain autopsy at death. Histopathological measures of vascular and AD neuropathology were obtained and analyzed. Results demonstrated that, among APOE ɛ4 carriers, elevated blood glucose was associated with more severe AD pathology. There was no such relationship with vascular pathology. In a relatively healthy sample with low vascular risk burden, midlife elevated blood glucose was associated with greater AD pathology among APOE ɛ4 carriers. A better understanding of interactive effects of APOE genotype and vascular risk on neuropathology has implications for identification of individuals at risk for decline and long-term preventive treatment.

Prevalence of Mild Cognitive Impairment and Its Subtypes among Chinese Older Adults: Role of Vascular Risk Factors

BACKGROUND/AIMS

The prevalence of mild cognitive impairment (MCI) and its subtypes among Chinese older adults, and the contribution of vascular risk factors (VRF) and vascular disorders to MCI remain unclear. This study aims to investigate the prevalence of MCI and its different subtypes, and clarify the role of VRF and vascular diseases in the occurrence of MCI.

METHODS

A random sample of 5,214 nondementia (DSM-IV) individuals aged ≥65 years underwent neuropsychological assessments and clinical examinations. MCI, including amnestic MCI-single domain (aMCI-SD), amnestic MCI-multiple domains (aMCI-MD), nonamnestic MCI-single domain (naMCI-SD), and nonamnestic MCI-multiple domains (naMCI-MD), was defined according to modifications of the Petersen criteria. VRF (smoking, obesity, and diabetes) and vascular disorders (myocardial infarction, atrial xFB01;brillation, stroke, and hypertension) were assessed based on information through self-report and medical records. Data were analyzed using multivariate logistic regression.

RESULTS

The prevalence of MCI was 11.33% (95% CI: 8.21-14.43), and that of aMCI-SD, aMCI-MD, naMCI-SD, and naMCI-MD was 4.48% (95% CI: 2.24-6.74), 2.09% (95% CI: 0.80-3.38), 4.22% (95% CI: 1.38-7.08), and 0.53% (95% CI: 0.32-0.75), respectively. The prevalence of MCI is higher in women than in men. Multivariate logistic regression analysis shows that VRF and vascular diseases were significantly related to increase the odds of MCI and its specific subtype.

CONCLUSIONS

The prevalence of MCI is almost 11% among Chinese older adults. VRF and vascular disorders are associated with MCI, especially naMCI.

Anxiety, Depression, and the Microbiome: A Role for Gut Peptides

The complex bidirectional communication between the gut and the brain is finely orchestrated by different systems, including the endocrine, immune, autonomic, and enteric nervous systems. Moreover, increasing evidence supports the role of the microbiome and microbiota-derived molecules in regulating such interactions; however, the mechanisms underpinning such effects are only beginning to be resolved. Microbiota-gut peptide interactions are poised to be of great significance in the regulation of gut-brain signaling. Given the emerging role of the gut-brain axis in a variety of brain disorders, such as anxiety and depression, it is important to understand the contribution of bidirectional interactions between peptide hormones released from the gut and intestinal bacteria in the context of this axis. Indeed, the gastrointestinal tract is the largest endocrine organ in mammals, secreting dozens of different signaling molecules, including peptides. Gut peptides in the systemic circulation can bind cognate receptors on immune cells and vagus nerve terminals thereby enabling indirect gut-brain communication. Gut peptide concentrations are not only modulated by enteric microbiota signals, but also vary according to the composition of the intestinal microbiota. In this review, we will discuss the gut microbiota as a regulator of anxiety and depression, and explore the role of gut-derived peptides as signaling molecules in microbiome-gut-brain communication. Here, we summarize the potential interactions of the microbiota with gut hormones and endocrine peptides, including neuropeptide Y, peptide YY, pancreatic polypeptide, cholecystokinin, glucagon-like peptide, corticotropin-releasing factor, oxytocin, and ghrelin in microbiome-to-brain signaling. Together, gut peptides are important regulators of microbiota-gut-brain signaling in health and stress-related psychiatric illnesses.

Cognitive and gait decrements among non-demented older adults with Type 2 diabetes or hypertension: a systematic review

OBJECTIVE

Older adults with Type 2 diabetes (DM2) and hypertension (HTN) often experience cognitive weaknesses. Growing evidence suggests that such weaknesses place patients at risk for gait disturbance and falls. The current systematic review evaluated (a) the impact of DM2 and HTN on cognition and gait and (b) the association between cognition and gait in the context of DM2 and HTN.

METHODS

PubMed was searched to identify studies published in English before 15 April 2017 that evaluated both cognition and gait among non-demented older adults either as a function of DM2 or HTN status or as a function of continuous variables that indicate disease severity and/or management (e.g. blood pressure, HbA1C). Risk of bias was assessed by examining the method of verifying HTN/DM2 and excluding dementia as well as included covariates.

RESULTS

In the majority of studies reviewed (n = 17), both DM2 and HTN status were associated with poorer cognitive and/or gait functioning (8 out of 10 studies). In addition, in 10 out of 11 studies cognition was reliably associated with gait. For continuous variables, higher systolic blood pressure (measured with ambulatory methods) was consistently related to poorer cognition and slower gait, but other continuous variables (e.g. HbA1C) were studied inconsistently with inconclusive results.

CONCLUSIONS

Cognitive and gait decrements are not only common in the context of HTN and DM2, but also are related to each other. This suggests that clinical neuropsychologists should address cognitive contributions to gait disturbance and falls in their clinical work and research with these patient populations.

Reactivation of hyperglycemia-induced hypocretin (HCRT) gene silencing by N-acetyl-d-mannosamine in the orexin neurons derived from human iPS cells

Orexin neurons regulate critical brain activities for controlling sleep, eating, emotions, and metabolism, and impaired orexin neuron function results in several neurologic disorders. Therefore, restoring normal orexin function and understanding the mechanisms of loss or impairment of orexin neurons represent important goals. As a step toward that end, we generated human orexin neurons from induced pluripotent stem cells (hiPSCs) by treatment with N-acetyl-d-mannosamine (ManNAc) and its derivatives. The generation of orexin neurons was associated with DNA hypomethylation, histone H3/H4 hyperacetylation, and hypo-O-GlcNAcylation on the HCRT gene locus, and, thereby, the treatment of inhibitors of SIRT1 and OGT were effective at inducing orexin neurons from hiPSCs. The prolonged exposure of orexin neurons to high glucose in culture caused irreversible silencing of the HCRT gene, which was characterized by H3/H4 hypoacetylation and hyper-O-GlcNAcylation. The DNA hypomethylation status, once established in orexin neurogenesis, was maintained in the HCRT-silenced orexin neurons, indicating that histone modifications, but not DNA methylation, were responsible for the HCRT silencing. Thus, the epigenetic status of the HCRT gene is unique to the hyperglycemia-induced silencing. Intriguingly, treatment of ManNAc and its derivatives reactivated HCRT gene expression, while inhibitors SIRT1 and the OGT did not. The present study revealed that the HCRT gene was silenced by the hyperglycemia condition, and ManNAc and its derivatives were useful for restoring the orexin neurons.

Short-Term Postoperative Cognitive Dysfunction and Inflammatory Response in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: A Pilot Study

Objectives

To assess the association between short-term postoperative cognitive dysfuction (POCD) and inflammtory response in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

Design

A prospective cohort study.

Setting

University medical centre.

Participants

Fifty-one adult patients who had undergone CRS-HIPEC and twenty control participants.

Measurements

The inflammatory marker levels in plasma and cognitive function were measured.

Results

Twenty (39.2%, 20/51) patients developed POCD at 1 w after CRS-HIPEC. The patients with POCD had higher serum interleukin 1β (IL-1β), serum amyloid A (SAA), S100 calcium-binding protein β (S-100β), and high mobility group box-1 protein (HMGB-1) levels at 1 and 24 h postoperatively than patients without POCD. There was an association between POCD and the maximum IL-1β and S-100β concentrations in serum, which remained following adjustment for age and FBS.

Conclusion

In this pilot study, perioperative inflammatory marker levels increase significantly after CRS-HIPEC in adult patients, and such elevations are associated with the development of short-term cognitive dysfunction after this complex surgery. These results suggested the need for a larger RCT to replicate and confirm these findings.

Towards the concept of disease-modifier in post-stroke or vascular cognitive impairment: a consensus report

BACKGROUND

Vascular cognitive impairment (VCI) is a complex spectrum encompassing post-stroke cognitive impairment (PSCI) and small vessel disease-related cognitive impairment. Despite the growing health, social, and economic burden of VCI, to date, no specific treatment is available, prompting the introduction of the concept of a disease modifier.

CONSENSUS AND SUGGESTIONS

Within this clinical spectrum, VCI and PSCI remain advancing conditions as neurodegenerative diseases with progression of both vascular and degenerative lesions accounting for cognitive decline. Disease-modifying strategies should integrate both pharmacological and non-pharmacological multimodal approaches, with pleiotropic effects targeting (1) endothelial and brain-blood barrier dysfunction; (2) neuronal death and axonal loss; (3) cerebral plasticity and compensatory mechanisms; and (4) degenerative-related protein misfolding. Moreover, pharmacological and non-pharmacological treatment in PSCI or VCI requires valid study designs clearly stating the definition of basic methodological issues, such as the instruments that should be used to measure eventual changes, the biomarker-based stratification of participants to be investigated, and statistical tests, as well as the inclusion and exclusion criteria that should be applied.

CONCLUSION

A consensus emerged to propose the development of a disease-modifying strategy in VCI and PSCI based on pleiotropic pharmacological and non-pharmacological approaches.

Comparative Proteomic Analysis of the Mitochondria-associated ER Membrane (MAM) in a Long-term Type 2 Diabetic Rodent Model

The mitochondria-associated ER membrane (MAM) plays a critical role in cellular energetics and calcium homeostasis; however, how MAM is affected under diabetic condition remains elusive. This study presented a comprehensive proteome profiling of isolated brain MAM from long-term type 2 diabetic mice vs. non-diabetic controls. MAM protein was extracted efficiently by a surfactant-aided precipitation/on-pellet digestion (SOD) method, and MAM proteome was quantified by an ion-current-based MS1 method combined with nanoLC-MS/MS. A total of 1,313 non-redundant proteins of MAM were identified, among which 144 proteins were found significantly altered by diabetes. In-depth IPA analysis identified multiple disease-relevant signaling pathways associated with the MAM proteome changes in diabetes, most significantly the unfolded protein response (UPR), p53, hypoxia-related transcription factors, and methyl CpG binding protein 2. Using immunofluorescence labeling we confirmed the activation of three UPR branches and increased ERp29 and calreticulin in diabetic retinas. Moreover, we found GRP75, a key MAM tethering protein, was drastically reduced by long-term diabetes. In vitro, acute high glucose treatment reduces ER-mitochondrial contact in retinal endothelial cells. This study provides first insight into the significant alterations in MAM proteome associated with activation of the UPR in diabetes, which may serve as novel benchmarks for the future studies of diabetic complications.

Neurological outcomes of antidiabetic therapy: What the neurologist should know

Considering the causative or contributory effects of diabetes mellitus on common neurological diseases such as polyneuropathy, stroke and dementia, modern antidiabetic drugs may be expected to reduce incidence or progression of these conditions. Nevertheless, most observed benefits have been small, except in the context of therapy for diabetes mellitus type I and new-onset polyneuropathy. Recently, semaglutide, a GLP-1 analog, has been shown to significantly reduce stroke incidence in a randomized controlled trial. Beneficial effects of antidiabetic drugs on stroke severity or outcome have been controversial, though. The level of risk conferred by diabetes mellitus, the complex pathophysiology of neurological diseases, issues of trial design, side-effects of antidiabetic drugs as well as co-medication might be interacting factors that determine the performance of antidiabetic therapy with respect to neurological outcomes. It might be speculated that early treatment of prediabetes might prevent cerebral arteriosclerosis, cognitive decline or polyneuropathy more effectively, but this remains to be demonstrated.

Glucagon-like Peptide-1 and the Central/Peripheral Nervous System: Crosstalk in Diabetes

Glucagon-like peptide-1 (GLP-1) is released in response to meals and exerts important roles in the maintenance of normal glucose homeostasis. GLP-1 is also important in the regulation of neurologic and cognitive functions. These actions are mediated via neurons in the nucleus of the solitary tract that project to multiple regions expressing GLP-1 receptors (GLP-1Rs). Treatment with GLP-1R agonists (GLP-1-RAs) reduces ischemia-induced hyperactivity, oxidative stress, neuronal damage and apoptosis, cerebral infarct volume, and neurologic damage, after cerebral ischemia, in experimental models. Ongoing human trials report a neuroprotective effect of GLP-1-RAs in Alzheimer's and Parkinson's disease. In this review, we discuss the role of GLP-1 and GLP-1-RAs in the nervous system with focus on GLP-1 actions on appetite regulation, glucose homeostasis, and neuroprotection.

Telmisartan-mediated metabolic profile conferred brain protection in diabetic hypertensive rats as evidenced by magnetic resonance imaging, behavioral studies and histology

Type 2 diabetes and hypertension are associated with cognitive dysfunction that includes pathological changes in brain tissue. It was speculated that the beneficial hypotensive effect of telmisartan, an angiotensin receptor 1 blocker, and its unique hypoglycemic effect due to its PPARγ-activation, could ameliorate the ​ pathological changes in the brain​ that accompany​ these diseases. We examined the effect of telmisartan on brain changes in magnetic resonance imaging (MRI) T2-weighted scans, and behavioral and histological findings in the Cohen-Rosenthal Diabetic Hypertensive (CRDH) rat. Baseline and post-treatment values with telmisartan/vehicle (3 months) of blood pressure, blood glucose levels, behavioral tests, brain MRI scanning and immunohistological staining were obtained. Telmisartan significantly lowered blood pressure and blood glucose levels; induced consistent T2 reduction in specific gray and white regions including hippocampus, corpus callosum, amygdala and cortical regions; and significantly improved performance on behavioral tasks. Immunohistological analysis of the brain revealed significant amelioration of diabetes/hypertension-induced changes in white matter regions and microglia, evidenced by preserved myelin (LBF marker), and improved microglial neuronal markers GFAP, GAP43 and Iba1 expression. In conclusion, the behavioral performance, longitudinal MRI study and histology staining revealed the protective effects of telmisartan on brain microstructure and cognitive function.

Methylglyoxal can mediate behavioral and neurochemical alterations in rat brain

Diabetes is associated with loss of cognitive function and increased risk for Alzheimer's disease (AD). Advanced glycation end products (AGEs) are elevated in diabetes and AD and have been suggested to act as mediators of the cognitive decline observed in these pathologies. Methylglyoxal (MG) is an extremely reactive carbonyl compound that propagates glycation reactions and is, therefore, able to generate AGEs. Herein, we evaluated persistent behavioral and biochemical parameters to explore the hypothesis that elevated exogenous MG concentrations, induced by intracerebroventricular (ICV) infusion, lead to cognitive decline in Wistar rats. A high and sustained administration of MG (3μmol/μL; subdivided into 6days) was found to decrease the recognition index of rats, as evaluated by the object-recognition test. However, MG was unable to impair learning-memory processes, as shown by the habituation in the open field (OF) and Y-maze tasks. Moreover, a single high dose of MG induced persistent alterations in anxiety-related behavior, diminishing the anxiety-like parameters evaluated in the OF test. Importantly, MG did not alter locomotion behavior in the different tasks performed. Our biochemical findings support the hypothesis that MG induces persistent alterations in the hippocampus, but not in the cortex, related to glyoxalase 1 activity, AGEs content and glutamate uptake. Glial fibrillary acidic protein and S100B content, as well as S100B secretion (astroglial-related parameters of brain injury), were not altered by ICV MG administration. Taken together, our data suggest that MG interferes directly in brain function and that the time and the levels of exogenous MG determine the different features that can be seen in diabetic patients.

Association Between Random Measured Glucose Levels in Middle and Old Age and Risk of Dementia-Related Death

OBJECTIVES

To investigate the association between random measured glucose levels in middle and old age and dementia-related death.

DESIGN

Population-based cohort study.

SETTING

Norwegian Counties Study (middle-aged individuals; 35-49) and Cohort of Norway participants (older individuals; 65-80).

PARTICIPANTS

Individuals without (n=74,630) and with (n=3,095) known diabetes mellitus (N=77,725); 67,865 without and 2,341 with diabetes mellitus were included in the complete case analyses (nonmissing for all included covariates), of whom 1,580 without and 131 with diabetes mellitus died from dementia-related causes.

MEASUREMENTS

Dementia-related death was ascertained according to the Norwegian Cause of Death Registry. Cox regression was used to assess the relationship between random glucose levels (nonfasting) in individuals without and with diabetes mellitus and dementia-related death. Education, smoking, cardiovascular disease, body mass index, cholesterol, blood pressure, and physical activity were adjusted for.

RESULTS

Individuals without diabetes mellitus at midlife with glucose levels between 6.5 and 11.0 mmol/L had a significantly greater risk of dementia-related death than those with levels less than 5.1 mmol/L (hazard ratio=1.32, 95% confidence interval=1.04-1.67) in a fully adjusted model. A dose-response relationship (P=.02) was observed. No significant association between high glucose levels in individuals aged 65 to 80 and dementia-related death was detected.

CONCLUSION

High random glucose levels measured in middle-aged but not older age persons without known diabetes mellitus were associated with greater risk of dementia-related death up to four decades later.

Metabonomic profiles delineate potential role of glutamate-glutamine cycle in db/db mice with diabetes-associated cognitive decline

Background

Diabetes-associated cognition decline is one of central nervous system complications in diabetic mellitus, while its pathogenic mechanism remains unclear. In this study, ¹H nuclear magnetic resonance-based metabonomics and immunohistochemistry was used to explore key metabolic alterations in hippocampus of type 2 diabetic db/db mice with cognition decline in order to advance understanding of mechanisms underlying the pathogenesis of the disease.

Results

Metabonomics reveals that lactate level was significantly increased in hippocampus of db/db mice with cognition decline compared with age-matched wild-type mice. Several tricarboxylic acid cycle intermediates including succinate and citrate were reduced in hippocampus of db/db mice with cognition decline. Moreover, an increase in glutamine level and a decrease in glutamate and γ-aminobutyric acid levels were observed in db/db mice. Results from immunohistochemistry analysis show that glutamine synthetase was increased and glutaminase and glutamate decarboxylase were decreased in db/db mice.

Conclusions

Our results suggest that the development of diabetes-associated cognition decline in db/db mice is most likely implicated in a reduction in energy metabolism and a disturbance of glutamate-glutamine shuttling between neurons and astrocytes in hippocampus.

Electronic supplementary material

The online version of this article (doi:10.1186/s13041-016-0223-5) contains supplementary material, which is available to authorized users.

Exendin-4 Reverses Biochemical and Functional Alterations in the Blood-Brain and Blood-CSF Barriers in Diabetic Rats

Diabetes mellitus (DM) is a metabolic disorder associated with micro- and macrovascular alterations that contribute to the cognitive impairment observed in diabetic patients. Signs of breakdown of the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) have been found in patients and animal models of DM. Breakdown of the BBB and BCSFB can lead to disruptions in cerebral homeostasis and eventually neural dysfunction and degeneration. However, our understanding of the biochemistry underlying barrier protein modifications is incomplete. Herein, we evaluated changes in the levels of specific proteins in the BBB (occludin, claudin-5, ZO-1, and aquaporin-4) and BCSFB (claudin-2 and aquaporin-1) in the hippocampus of diabetic rats, and we also investigated the functional alterations in these barriers. In addition, we evaluated the ability of exendin-4 (EX-4), a glucagon-like peptide-1 agonist that can cross the BBB to reverse the functional and biochemical modifications observed in these animals. We observed a decrease in BBB proteins (except ZO-1) in diabetic rats, whereas the EX-4 treatment recovered the occludin and aquaporin-4 levels. Similarly, we observed a decrease in BCSFB proteins in diabetic rats, whereas EX-4 reversed such changes. EX-4 also reversed alterations in the permeability of the BBB and BCSFB in diabetic rats. Additionally, altered cognitive parameters in diabetic rats were improved by EX-4. These data further our understanding of the alterations in the central nervous system caused by DM, particularly changes in the proteins and permeability of the brain barriers, as well as cognitive dysfunction. Furthermore, these data suggest a role for EX-4 in therapeutic strategies for cognitive dysfunction in DM.

Antioxidant treatment ameliorates experimental diabetes-induced depressive-like behaviour and reduces oxidative stress in brain and pancreas

Studies have shown a relationship between diabetes mellitus (DM) and the development of major depressive disorder. Alterations in oxidative stress are associated with the pathophysiology of both diabetes mellitus and major depressive disorder. This study aimed to evaluate the effects of antioxidants N-acetylcysteine and deferoxamine on behaviour and oxidative stress parameters in diabetic rats. To this aim, after induction of diabetes by a single dose of alloxan, Wistar rats were treated with N-acetylcysteine or deferoxamine for 14 days, and then depressive-like behaviour was evaluated. Oxidative stress parameters were assessed in the prefrontal cortex, hippocampus, amygdala, nucleus accumbens and pancreas. Diabetic rats displayed depressive-like behaviour, and treatment with N-acetylcysteine reversed this alteration. Carbonyl protein levels were increased in the prefrontal cortex, hippocampus and pancreas of diabetic rats, and both N-acetylcysteine and deferoxamine reversed these alterations. Lipid damage was increased in the prefrontal cortex, hippocampus, amygdala and pancreas; however, treatment with N-acetylcysteine or deferoxamine reversed lipid damage only in the hippocampus and pancreas. Superoxide dismutase activity was decreased in the amygdala, nucleus accumbens and pancreas of diabetic rats. In diabetic rats, there was a decrease in catalase enzyme activity in the prefrontal cortex, amygdala, nucleus accumbens and pancreas, but an increase in the hippocampus. Treatment with antioxidants did not have an effect on the activity of antioxidant enzymes. In conclusion, animal model of diabetes produced depressive-like behaviour and oxidative stress in the brain and periphery. Treatment with antioxidants could be a viable alternative to treat behavioural and biochemical alterations induced by diabetes.

Interactive effects of diabetes and impaired kidney function on cognitive performance in old age: a population-based study

Background

The interactive effect between diabetes and impaired kidney function on cognitive impairment in older adults has not yet been reported. The aim of this study was to investigate the association of diabetes and impaired kidney function with cognitive impairment among Chinese older people living in a rural area.

Methods

This cross-sectional study included 1,358 participants (age ≥60 years; 60.5 % women) in the population-based Confucius Hometown Aging Project in Shandong, China. Data on demographics, lifestyle factors, health history, use of medications, global cognitive function, and kidney function were collected through structured interviews, clinical examinations, and blood tests. We defined diabetes as a fasting plasma glucose level ≥7.0 mmol/l or use of hypoglycemic agents, impaired kidney function as glomerular filtration rate estimated from cystatin C (eGFR_cys) <60 ml/min/1.73 m². Cognitive impairment was defined using the education-based cut-off scores of Mini-Mental State Examination (MMSE). Data were analyzed using multiple general linear and logistic regression models.

Results

Cognitive impairment was defined in 197 (14.5 %) persons. The multi-adjusted β coefficient of MMSE score associated with diabetes was −0.06 (95 % confidence interval [CI], −0.16, 0.03); the corresponding figures associated with eGFR_cys <60, 60–89.9, and ≥90 ml/min/1.73 m² were −0.15 (−0.28, −0.02), −0.01 (−0.10, 0.08), and 0 (reference) (P_trend = 0.046), respectively. Diabetes and impaired kidney function showed an interactive effect on cognitive impairment (P_interaction = 0.02). Compared with individuals having neither diabetes nor impaired kidney function, those with both conditions had a multi-adjusted odds ratio of 4.23 (95 % CI, 2.10–8.49) for cognitive impairment. The relative excess risk due to interaction was 2.74.

Conclusions

This study suggests that concurrent presence of diabetes and impaired kidney function is associated with a substantial likelihood for cognitive impairment in older adults.

Cocoa, glucose tolerance, and insulin signaling: cardiometabolic protection

Experimental and clinical evidence reported that some polyphenol-rich natural products may offer opportunities for the prevention and treatment of type 2 diabetes, due to their biological properties. Natural products have been suggested to modulate carbohydrate metabolism by various mechanisms, such as restoring β-cell integrity and physiology and enhancing insulin-releasing activity and glucose uptake. Endothelium is fundamental in regulating arterial function, whereas insulin resistance plays a pivotal role in pathophysiological mechanisms of prediabetic and diabetic states. Glucose and insulin actions in the skeletal muscle are improved by insulin-dependent production of nitric oxide, favoring capillary recruitment, vasodilatation, and increased blood flow. Endothelial dysfunction, with decreased nitric oxide bioavailability, is a critical step in the development of atherosclerosis. Furthermore, insulin resistance has been described, at least in part, to negatively affect endothelial function. Consistent with this, conditions of insulin resistance are usually linked to endothelial dysfunction, and the exposure of the endothelial cells to cardiovascular risk factors such as hypertension, dyslipidemia, and hyperglycemia is associated with reduced nitric oxide bioavailability, resulting in impaired endothelial-dependent vasodilatation. Moreover, endothelial dysfunction has been described as an independent predictor of cardiovascular risk and events. Cocoa and cocoa flavonoids may positively affect the pathophysiological mechanisms involved in insulin resistance and endothelial dysfunction with possible benefits in the prevention of cardiometabolic diseases.

Comprehensive investigation of postmortem glucose levels in blood and body fluids with regard to the cause of death in forensic autopsy cases

The serum glucose level is regulated within a narrow range by multiple factors under physiological conditions, but is greatly modified in the death process and after death. The present study comprehensively investigated glucose levels in blood and body fluids, including pericardial fluid (PCF), cerebrospinal fluid (CSF) and vitreous humor, reviewing forensic autopsy cases (n=672). Right heart blood glucose level was often higher than at other sites, and the CSF glucose level was the lowest, showing greater dissociation in acute/subacute death cases. The glucose level was higher in the diabetic (high HbA1c) than in the non-diabetic (low HbA1c) group at each site (p<0.01-0.0001). Fatal diabetic ketoacidosis cases had evidently high glucose levels at each site; whereas in the non-diabetic group, blood glucose level was higher in fatal alcohol abuse, saltwater drowning, electrocution, cerebrovascular disease and sudden cardiac death due to ischemic heart disease. Fatal methamphetamine (MA) abuse, sepsis, malnutrition (starvation) and hypoglycemia due to antidiabetics showed markedly lower blood glucose levels. Ketones in bilateral cardiac blood and PCF were increased in diabetic ketoacidosis and fatal alcohol abuse as well as in most cases of hyperthermia (heatstroke), hypothermia (cold exposure) and malnutrition. These findings suggest that combined analysis of glucose, HbA1c and ketones in blood and body fluids is useful to investigate not only fatal diabetic metabolic disorders but also death processes due to other causes, including alcohol and MA abuse, as well as thermal disorders, sepsis and malnutrition.

Clinical Characteristics for the Relationship between Type-2 Diabetes Mellitus and Cognitive Impairment: A Cross-Sectional Study

We explored the potential differences in cognitive status, lipid and glucose metabolism, ApoEε4 alleles and imaging between diabetic and non-diabetic subjects. 83 subjects with normal cognitive function and 114 mild cognitive impaired patients were divided into four groups by history of diabetes. General demographics was collected from all participants followed by MRI scan, biochemical examinations and a series of neuropsychological tests. Student's t test, multiple regressions and one-way ANOVA were applied to investigate the differences between groups. Comparing diabetic patients with non-diabetic subjects in the mild cognitive impaired group, we found several decreased items in recall of three words in MMSE (p=0.020), AVLT and SCWT (p<0.050). The multiple linear regression revealed that two-hour glucose level (B= -0.255, p<0.001) and fasting C-peptide (B= -0.466, p=0.001) had negative effects on the score of MMSE. In addition, diabetic patients treated with insulin and other diabetes medication performed better in part of the AVLT (p<0.050) compared to patients with insulin treatment or oral antidiabetic medication only. Patients with metformin medication had a better memory outcome compared to patients with sulphonylurea medication in the AVLT long delay free recall (p =0.010). These findings show that patients of mild cognitive impairment with diabetes mellitus have a worse outcome in attention, information processing speed and memory compared to non-diabetic patients. Higher two-hour glucose level and C-peptide level may be risk factors for severe cognitive impairment in type-2 diabetes mellitus patients. The results of this study also suggest that medication may have effects on cognitive function.

Mechanisms linking brain insulin resistance to Alzheimer's disease

Several studies have indicated that Diabetes Mellitus (DM) can increase the risk of developing Alzheimer's disease (AD). This review briefly describes current concepts in mechanisms linking DM and insulin resistance/deficiency to AD. Insulin/insulin-like growth factor (IGF) resistance can contribute to neurodegeneration by several mechanisms which involve: energy and metabolism deficits, impairment of Glucose transporter-4 function, oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, accumulation of AGEs, ROS and RNS with increased production of neuro-inflammation and activation of pro-apoptosis cascade. Impairment in insulin receptor function and increased expression and activation of insulin-degrading enzyme (IDE) have also been described. These processes compromise neuronal and glial function, with a reduction in neurotransmitter homeostasis. Insulin/IGF resistance causes the accumulation of AβPP-Aβ oligomeric fibrils or insoluble larger aggregated fibrils in the form of plaques that are neurotoxic. Additionally, there is production and accumulation of hyper-phosphorylated insoluble fibrillar tau which can exacerbate cytoskeletal collapse and synaptic disconnection.

The mitochondrial O-linked N-acetylglucosamine transferase (mOGT) in the diabetic patient could be the initial trigger to develop Alzheimer disease

Diabetes mellitus (DM) is considered a risk factor for the development of Alzheimer disease (AD); however, how DM favors evolution of AD is still insufficiently understood. Hyperglycemia in DM is associated to an increase in mitochondrial reactive oxygen species (ROS) generation, as well as damage of hippocampal cells, reflected by changes in morphological and mitochondrial functionality. Similar mitochondrial damage has been observed when amyloid beta (Aβ) accumulates in the brain of AD patients. In DM, the excess of glucose in the brain induces higher activity of the hexosamine biosynthesis pathway (HBP), it synthesizes UDP-N-acetylglucosamine (UDP-GlcNAc), which is used by O-linked N-acetylglucosamine transferase (OGT) to catalyze O-GlcNAcylation of numerous proteins. Although O-GlcNAcylation plays an important role in maintaining structure and cellular functionality, chronic activity of this pathway has been associated with insulin resistance and hyperglycemia-induced glucose toxicity. Three different forms of OGT are known: nucleocytoplasmic (ncOGT), short (sOGT), and mitochondrial (mOGT). Previous reports showed that overexpression of ncOGT is not toxic to the cell; in contrast, overexpression of mOGT is associated with cellular apoptosis. In this work, we suggest that hyperglycemia in the diabetic patient could induce greater expression and activity of mOGT, modifying the structure and functionality of mitochondria in hippocampal cells, accelerating neuronal damage, and favoring the start of AD. In consequence, mOGT activity could be a key point for AD development in patients with DM.