Cognitive impairment and type 2 diabetes mellitus: Focus of SGLT2 inhibitors treatment

Association between sodium-glucose cotransporter-2 (SGLT2) inhibitors and macular degeneration in patients with diabetes: a nationwide population-based study in Taiwan

AIMS

Evidence showed that SGLT2 inhibitors have greater protective effects against retinal diseases compared to other hypoglycemic agents. Thus, we explore the association between SGLT2 inhibitor usage and macular degeneration (MD) in Taiwanese patients with diabetes.

METHODS

The National Health Insurance (NHI) program's claim data are released as the National Health Insurance Research Database (NHIRD). This database covers more than 99% of the residents in Taiwan. We included data on patients who were newly diagnosed with type 2 diabetes mellitus (ICD-9-CM: 250, exclude 250.1x; ICD-10-CM: E11), with an age at diagnosis of over 20 years as our study population. Patients who received (sodium-glucose cotransporter 2 inhibitor) SGLT2i (ATC code: A10BK) over 90 days in 2016-2019 were defined as the SGLT2i cohort. Conversely, patients who did never received SGLT2i were defined as the non-SGLT2i cohort. The exclusion criteria were having MD before the index date, receiving SGLT2i within 1-89 days, and missing data on sex, age, or days of SGLT2i usage. Two cohorts were matched by 1:1 propensity score matching, which was based on age, sex, payroll bracket grade, urbanization, comorbidities, and medications.

RESULTS

Compared to non-SGLT2i cohort, patients who received SGLT2i had a significantly lower risk of MD (adjusted hazard ratio = 0.70, 95%CI = 0.66-0.75).

CONCLUSIONS

We found that SGLT2is has a strong protective effect against MD in patients with diabetes. SGLT2is may have benefits beyond glycemic control in patients with DR. However, additional clinical and experimental studies are required.

The relationship between SGLT2 and systemic blood pressure regulation

The sodium-glucose cotransporter 2 (SGLT2) is a glucose transporter that is located within the proximal tubule of the kidney's nephrons. While it is typically associated with the kidney, it was later identified in various areas of the central nervous system, including areas modulating cardiorespiratory regulation like blood pressure. In the kidney, SGLT2 functions by reabsorbing glucose from the nephron's tubule into the bloodstream. SGLT2 inhibitors are medications that hinder the function of SGLT2, thus preventing the absorption of glucose and allowing for its excretion through the urine. While SGLT2 inhibitors are not the first-line choice, they are given in conjunction with other pharmaceutical interventions to manage hyperglycemia in individuals with diabetes mellitus. SGLT2 inhibitors also have a surprising secondary effect of decreasing blood pressure independent of blood glucose levels. The implication of SGLT2 inhibitors in lowering blood pressure and its presence in the central nervous system brings to question the role of SGLT2 in the brain. Here, we evaluate and review the function of SGLT2, SGLT2 inhibitors, their role in blood pressure control, the future of SGLT2 inhibitors as antihypertensive agents, and the possible mechanisms of SGLT2 blood pressure control in the central nervous system.

The Therapeutic Effect of Buyang Huanwu Decoction on Mild Cognitive Impairment (MCI) in Patients with Diabetes

OBJECTIVE

This study aims to comprehensively verify the efficacy of Buyang Huanwu Decoction in improving cognitive function in patients with diabetes.

METHODS

Patients clinically diagnosed with mild cognitive impairment (MCI) assigned to either the placebo group or the Buyang Huanwu Decoction group. After strict screening and exclusions, a total of 156 participants completed the clinical trial, with 76 in the placebo group and 80 in the Buyang Huanwu Decoction group.

RESULTS

After treatment, Buyang Huanwu Decoction group showed higher Mini-Mental State Examination and Montreal Cognitive Assessment scores compared to placebo (p < 0.05). Memory and Executive Screening, Boston Naming Test, and Animal Fluency Test scores were also higher in the treatment group (p < 0.05). No significant differences were found in DST and CDT scores (p > 0.05). Trail Making Test scores were lower in the treatment group (p < 0.05). No significant difference was observed between the two groups in terms of complications (p > 0.05).

CONCLUSION

Patients receiving Buyang Huanwu Decoction treatment demonstrated improvement in cognitive function, showing positive effects and providing preliminary evidence for the role of Buyang Huanwu Decoction in improving cognitive function in patients with diabetes. This suggests its potential for clinical application and further promotion.

The role of neurovascular coupling dysfunction in cognitive decline of diabetes patients

Neurovascular coupling (NVC) is an important mechanism to ensure adequate blood supply to active neurons in the brain. NVC damage can lead to chronic impairment of neuronal function. Diabetes is characterized by high blood sugar and is considered an important risk factor for cognitive impairment. In this review, we provide fMRI evidence of NVC damage in diabetic patients with cognitive decline. Combined with the exploration of the major mechanisms and signaling pathways of NVC, we discuss the effects of chronic hyperglycemia on the cellular structure of NVC signaling, including key receptors, ion channels, and intercellular connections. Studying these diabetes-related changes in cell structure will help us understand the underlying causes behind diabetes-induced NVC damage and early cognitive decline, ultimately helping to identify the most effective drug targets for treatment.

Drug Safety Evaluation of Sodium-Glucose Cotransporter 2 Inhibitors in Diabetic Comorbid Patients by Review of Systemic Extraglycemic Effects

Purpose

The aim of this study is to evaluate the safety of this drug in diabetic patients with comorbidities of all systems.

Method

In this review, the beneficial effects of this drug and its mechanism on the disorders of every system of humans in relation to diabetes have been studied, and finally, its adverse effects have also been discussed. The search for relevant information is carried out in the PubMed and Google Scholar databases by using the following terms: diabetes mellitus type 2, SGLT, SGLT2 inhibitors, (SGLT2 inhibitors) AND (Pleiotropic effects). All English-published articles from 2016 to 2023 have been used in this study. It should be noted that a small number of articles published before 2016 have been used in the introduction and general informations.

Results

Its beneficial effects on improving cardiovascular disease risk factors and reducing adverse events caused by cardiovascular and renal diseases have proven in most large clinical studies that these effects are almost certain. It also has beneficial effects on other human systems such as the respiratory system, the gastrointestinal system, the circulatory system, and the nervous system; more of them are at the level of clinical and pre-clinical trials but have not been proven in large clinical trials or meta-analyses.

Conclusion

With the exception of a few adverse effects, this drug is considered a good choice and safe for all diabetic patients with comorbidities of all systems.

Factors influencing the bariatric surgery treatment of bariatric surgery candidates in underdeveloped areas of China

BACKGROUND

From year to year, the proportion of people living with overweight and obesity in China rises, along with the prevalence of diseases linked to obesity. Although bariatric surgery is gaining popularity, there are still several issues with its promotion compared to Western nations. Since less developed places in China are more widespread due to disparities in the development of different regions, there has been little exploration of the factors that might be related to acceptance of bariatric surgery in these regions.

METHODS

Patients who visited the Department of Gastrointestinal Surgery at the North Sichuan Medical College Affiliated Hospital from 2018 to 2022 and had obesity or other relevant metabolic problems were surveyed using a questionnaire. The relationship between demographic factors, socioeconomic status, and acceptance of bariatric surgery was analyzed.

RESULTS

Of 334 patients, 171 had bariatric surgery. BMI, education level, marriage history, medical insurance, family support, and a history of type 2 diabetes were all linked to having bariatric surgery, according to a univariate analysis. In a multivariate analysis, BMI (P = 0.02), education (P = 0.02), family support (P<0.001), medical insurance coverage (P<0.001), and history of type 2 diabetes (P = 0.004) were all positively associated with a willingness to have bariatric surgery. Among 163 non-bariatric patients with obesity, 15.3% were not opposed to surgery but preferred trying medication first, 54.6% leaned towards medical therapy, and 30% were hesitant. Additionally, a majority of patients (48.55%) often lacked adequate knowledge about weight reduction therapy. Age, height, gender, smoking, drinking, family history of type 2 diabetes, education, and marital status did not significantly differ (P > 0.05).

CONCLUSIONS

Many patients are concerned about the safety of surgical treatment and the possibility of regaining weight. Due to the relatively high cost of bariatric surgery, they tend to choose medical treatment. To enhance the acceptance of bariatric surgery in underdeveloped regions of China, it is crucial to focus on disseminating knowledge about bariatric surgery, offer pertinent health education to the community, and foster support from patients' families. The government should pay more attention to obesity and provide support in the form of medical insurance.

The impact of sodium-glucose co-transporter-2 inhibitors on dementia and cardiovascular events in diabetic patients with atrial fibrillation

AIMS

The effectiveness of sodium-glucose co-transporter-2 inhibitors (SGLT2i) on incident dementia in patients with diabetes and atrial fibrillation (AF) remains unknown. This study aimed to investigate the association between SGLT2i and the risk of incident dementia in diabetic patients with AF, and to explore the interactions with oral anticoagulants or dipeptidyl peptidase-4 inhibitors (DPP4i).

MATERIALS AND METHODS

We conducted a cohort study using Taiwan's National Health Insurance Research Database. Patients with diabetes and AFwithout a prior history of established cardiovascular diseases, were identified. Using propensity score matching, 810 patients receiving SGLT2i were matched with 1620 patients not receiving SGLT2i. The primary outcome was incident dementia, and secondary outcomes included composite cardiovascular events and mortality.

RESULTS

After up to 5 years of follow-up, SGLT2i use was associated with a significantly lower risk of incident dementia (hazard: 0.71, 95% confidence interval: 0.51-0.98), particularly vascular dementia (HR: 0.44, 95% CI: 0.24-0.82). SGLT2i was related to reduced risks of AF-related hospitalisation (HR: 0.72, 95% CI: 0.56-0.93), stroke (HR: 0.75, 95% CI: 0.60-0.94), and all-cause death (HR: 0.33, 95% CI: 0.24-0.44). The protective effects were consistent irrespective of the concurrent use of non-vitamin K antagonist oral anticoagulants (NOACs) or DPP4i.

CONCLUSIONS

In diabetic patients with AF, SGLT2i was associated with reduced risks of incident dementia, AF-related hospitalisation, stroke, and all-cause death. The protective effects were independent of either concurrent use of NOACs or DPP4i.

Cognitive Benefits of Sodium-Glucose Co-Transporters-2 Inhibitors in the Diabetic Milieu

Patients with diabetes are at higher risk of cognitive impairment and memory loss than the normal population. Thus, using hypoglycemic agents to improve brain function is important for diabetic patients. Sodium-glucose cotransporters-2 inhibitors (SGLT2i) are a class of therapeutic agents used in the management of diabetes that has some pharmacologic effects enabling them to fight against the onset and progress of memory deficits. Although the exact mediating pathways are not well understood, emerging evidence suggests that SGLT2 inhibition is associated with improved brain function. This study reviewed the possible mechanisms and provided evidence suggesting SGLT2 inhibitors could ameliorate cognitive deficits.

Analysis of the management and therapeutic performance of diabetes mellitus employing special target

Diabetes mellitus (DM) is a chronic metabolic condition characterized predominantly by hyperglycemia. The most common causes contributing to the pathophysiology of diabetes are insufficient insulin secretion, resistance to insulin's tissue-acting effects, or a combination of both. Over the last 30 years, the global prevalence of diabetes increased from 4% to 6.4%. If no better treatment or cure is found, this amount might climb to 430 million in the coming years. The major factors of the disease's deterioration include age, obesity, and a sedentary lifestyle. Finding new therapies to manage diabetes safely and effectively without jeopardizing patient compliance has always been essential. Among the medications available to manage DM on this journey are glucagon-like peptide-1 agonists, thiazolidinediones, sulphonyl urease, glinides, biguanides, and insulin-targeting receptors discovered more than 10 years ago. Despite the extensive preliminary studies, a few clinical observations suggest this process is still in its early stages. The present review focuses on targets that contribute to insulin regulation and may be employed as targets in treating diabetes since they may be more efficient and secure than current and traditional treatments.

A Correlative Relationship Between Heart Failure and Cognitive Impairment: A Narrative Review

Heart failure (HF) is a chronic condition affecting millions of people worldwide. While the cardinal manifestations of HF are related to the cardiovascular system, it has become progressively evident that mild cognitive impairment (MCI) is also a significant complication of the disease. In fact, a significant number of patients with HF may experience MCI, which can manifest as deficits in attention, memory, executive function, and processing speed. The mechanisms responsible for cognitive dysfunction in HF are intricate and multifactorial. Possible factors contributing to this condition include decreased cerebral blood flow, thrombogenicity associated with HF, systemic inflammatory conditions, and proteotoxicity. MCI in HF has significant clinical implications, as it is linked to poorer quality of life, increased morbidity and mortality, and higher healthcare costs. Additionally, MCI can disrupt self-care behaviors, adherence to medication, and decision-making abilities, all of which are crucial for effectively managing HF. However, there is currently no gold standard diagnostic tool and follow-up strategy for MCI in HF patients. There is limited knowledge on the prevention and treatment of MCI. In conclusion, MCI is a common and clinically important complication of HF. Considering the substantial influence of MCI on patient outcomes, it is imperative for healthcare providers to be cognizant of this issue and integrate cognitive screening and management strategies into the care of HF patients.

Dapagliflozin/Hesperidin Combination Mitigates Lipopolysaccharide-Induced Alzheimer's Disease in Rats

Alzheimer's disease (AD) is the most common form of neurodegenerative disorders worldwide. Its pathologic features include massive neuroinflammation with abnormal deposition of β-amyloid peptide in the cerebral tissues leading to degeneration of the brain neurons. Adverse effects associated with the traditional drugs used for the treatment of this pathological condition have directed the research efforts towards searching for alternative effective agents with minimal adverse effects. The aim of this study was to elucidate the potential ameliorative effects of dapagliflozin and/or hesperidin on Alzheimer's disease (AD) induced by lipopolysaccharide (LPS) injection in rats. In a rodent model of AD, the effect of dapagliflozin with or without hesperidin on the biochemical parameters and the behavioral tests as well as the histopathological parameters was determined. Each of dapagliflozin and hesperidin restored the behavioral tests to the reference values, augmented the antioxidant defense mechanisms, ameliorated the neuronal inflammatory responses, combatted the changes in Toll-like receptor-4 (TLR-4)/High-mobility group box 1 (HMGB1) protein signaling and receptors of advanced glycation end products (RAGE) levels, and restored the balance between the apoptotic signals and autophagy in the hippocampal tissues. Additionally, both agents exhibited an outstanding ability to combat LPS-induced perturbations in the histopathological and electron microscopic image of the brain tissues. These favorable effects were significantly encountered in the group treated with dapagliflozin/hesperidin combination when compared versus animals treated with either dapagliflozin or hesperidin. In conclusion, inhibition of the hippocampal HMGB1/TLR4/RAGE signaling, the pro-inflammatory axis, and apoptosis alongside augmentation of the antioxidant defenses and autophagy can be regarded as beneficial effects by which dapagliflozin/hesperidin combination may combat LPS-triggered AD.

The role of autophagy in the treatment of type II diabetes and its complications: a review

Type II diabetes mellitus (T2DM) is a chronic metabolic disease characterized by prolonged hyperglycemia and insulin resistance (IR). Its incidence is increasing annually, posing a significant threat to human life and health. Consequently, there is an urgent requirement to discover effective drugs and investigate the pathogenesis of T2DM. Autophagy plays a crucial role in maintaining normal islet structure. However, in a state of high glucose, autophagy is inhibited, resulting in impaired islet function, insulin resistance, and complications. Studies have shown that modulating autophagy through activation or inhibition can have a positive impact on the treatment of T2DM and its complications. However, it is important to note that the specific regulatory mechanisms vary depending on the target organ. This review explores the role of autophagy in the pathogenesis of T2DM, taking into account both genetic and external factors. It also provides a summary of reported chemical drugs and traditional Chinese medicine that target the autophagic pathway for the treatment of T2DM and its complications.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Advances in Research on Type 2 Diabetes Mellitus Targets and Therapeutic Agents

Diabetes mellitus is a chronic multifaceted disease with multiple potential complications, the treatment of which can only delay and prolong the terminal stage of the disease, i.e., type 2 diabetes mellitus (T2DM). The World Health Organization predicts that diabetes will be the seventh leading cause of death by 2030. Although many antidiabetic medicines have been successfully developed in recent years, such as GLP-1 receptor agonists and SGLT-2 inhibitors, single-target drugs are gradually failing to meet the therapeutic requirements owing to the individual variability, diversity of pathogenesis, and organismal resistance. Therefore, there remains a need to investigate the pathogenesis of T2DM in more depth, identify multiple therapeutic targets, and provide improved glycemic control solutions. This review presents an overview of the mechanisms of action and the development of the latest therapeutic agents targeting T2DM in recent years. It also discusses emerging target-based therapies and new potential therapeutic targets that have emerged within the last three years. The aim of our review is to provide a theoretical basis for further advancement in targeted therapies for T2DM.

Risk factors and drug discovery for cognitive impairment in type 2 diabetes mellitus using artificial intelligence interpretation and graph neural networks

Background

Among the 382 million diabetic patients worldwide, approximately 30% experience neuropathy, and one-fifth of these patients eventually develop diabetes cognitive impairment (CI). However, the mechanism underlying diabetes CI remains unknown, and early diagnostic methods or effective treatments are currently not available.

Objective

This study aimed to explore the risk factors for CI in patients with type 2 diabetes mellitus (T2DM), screen potential therapeutic drugs for T2DM-CI, and provide evidence for preventing and treating T2DM-CI.

Methods

This study focused on the T2DM population admitted to the First Affiliated Hospital of Hunan College of Traditional Chinese Medicine and the First Affiliated Hospital of Hunan University of Chinese Medicine. Sociodemographic data and clinical objective indicators of T2DM patients admitted from January 2018 to December 2022 were collected. Based on the Montreal Cognitive Assessment (MoCA) Scale scores, 719 patients were categorized into two groups, the T2DM-CI group with CI and the T2DM-N group with normal cognition. The survey content included demographic characteristics, laboratory serological indicators, complications, and medication information. Six machine learning algorithms were used to analyze the risk factors of T2DM-CI, and the Shapley method was used to enhance model interpretability. Furthermore, we developed a graph neural network (GNN) model to identify potential drugs associated with T2DM-CI.

Results

Our results showed that the T2DM-CI risk prediction model based on Catboost exhibited superior performance with an area under the receiver operating characteristic curve (AUC) of 0.95 (specificity of 93.17% and sensitivity of 78.58%). Diabetes duration, age, education level, aspartate aminotransferase (AST), drinking, and intestinal flora were identified as risk factors for T2DM-CI. The top 10 potential drugs related to T2DM-CI, including Metformin, Liraglutide, and Lixisenatide, were selected by the GNN model. Some herbs, such as licorice and cuscutae semen, were also included. Finally, we discovered the mechanism of herbal medicine interventions in gut microbiota.

Conclusion

The method based on Interpreting AI and GNN can identify the risk factors and potential drugs associated with T2DM-CI.

Newer glucose-lowering drugs and risk of dementia: A systematic review and meta-analysis of observational studies

BACKGROUND

Preclinical studies have suggested potential beneficial effects of newer glucose-lowering drugs (GLDs) including dipeptidyl peptidase (DPP)-4 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and sodium glucose co-transporter-2 (SGLT2) inhibitors, in protecting humans against cognitive decline and dementia. However, population studies aiming to demonstrate such cognitive benefits from newer GLDs have produced mixed findings. This meta-analysis aimed to evaluate the association between newer GLDs and risk of dementia in adults with type 2 diabetes (T2D).

METHODS

Electronic databases were searched up to March 11, 2022 to include observational studies that examined the association between DPP-4 inhibitors, GLP-1RAs, and SGLT2 inhibitors and risk of dementia (including all-cause dementia, Alzheimer's disease [AD], and vascular dementia [VD]) in people with T2D. We conducted a random-effects meta-analysis to calculate the relative risk (RR) with 95% confidence interval (CI) for each class of newer GLD.

RESULTS

Ten studies (from nine articles) involving 819,511 individuals with T2D were included. Three studies found that SGLT2 inhibitor users had a lower risk of all-cause dementia than non-SGLT2 inhibitor users (RR, 0.62; 95% CI, 0.39-0.97). Five studies found that users versus nonusers of GLP-1RAs were associated with a significant reduction in the risk of all-cause dementia (RR, 0.72; 95% CI, 0.54-0.97). However, a meta-analysis for AD and VD was unavailable for SGLT2 inhibitors and GLP-1RAs because only one study was included for each drug. In seven studies, users vs. nonusers of DPP-4 inhibitors were significantly associated with a decreased risk of all-cause dementia (RR, 0.84; 95% CI, 0.74-0.94) and VD (RR, 0.59; 95% CI, 0.47-0.75) but not AD (RR, 0.82; 95% CI, 0.63-1.08).

CONCLUSION

Newer GLDs were associated with a decreased risk of all-cause dementia in people with T2D. Because of the observational nature and significant heterogeneity between studies, the results should be interpreted with caution. Further research is warranted to confirm our findings.

Shared biological mechanisms of depression and obesity: focus on adipokines and lipokines

Depression and obesity are both common disorders currently affecting public health, frequently occurring simultaneously within individuals, and the relationship between these disorders is bidirectional. The association between obesity and depression is highly co-morbid and tends to significantly exacerbate metabolic and related depressive symptoms. However, the neural mechanism under the mutual control of obesity and depression is largely inscrutable. This review focuses particularly on alterations in systems that may mechanistically explain the in vivo homeostatic regulation of the obesity and depression link, such as immune-inflammatory activation, gut microbiota, neuroplasticity, HPA axis dysregulation as well as neuroendocrine regulators of energy metabolism including adipocytokines and lipokines. In addition, the review summarizes potential and future treatments for obesity and depression and raises several questions that need to be answered in future research. This review will provide a comprehensive description and localization of the biological connection between obesity and depression to better understand the co-morbidity of obesity and depression.

Iron and Ferroptosis More than a Suspect: Beyond the Most Common Mechanisms of Neurodegeneration for New Therapeutic Approaches to Cognitive Decline and Dementia

Neurodegeneration is a multifactorial process that involves multiple mechanisms. Examples of neurodegenerative diseases are Parkinson's disease, multiple sclerosis, Alzheimer's disease, prion diseases such as Creutzfeldt-Jakob's disease, and amyotrophic lateral sclerosis. These are progressive and irreversible pathologies, characterized by neuron vulnerability, loss of structure or function of neurons, and even neuron demise in the brain, leading to clinical, functional, and cognitive dysfunction and movement disorders. However, iron overload can cause neurodegeneration. Dysregulation of iron metabolism associated with cellular damage and oxidative stress is reported as a common event in several neurodegenerative diseases. Uncontrolled oxidation of membrane fatty acids triggers a programmed cell death involving iron, ROS, and ferroptosis, promoting cell death. In Alzheimer's disease, the iron content in the brain is significantly increased in vulnerable regions, resulting in a lack of antioxidant defenses and mitochondrial alterations. Iron interacts with glucose metabolism reciprocally. Overall, iron metabolism and accumulation and ferroptosis play a significant role, particularly in the context of diabetes-induced cognitive decline. Iron chelators improve cognitive performance, meaning that brain iron metabolism control reduces neuronal ferroptosis, promising a novel therapeutic approach to cognitive impairment.

The gut microbiota-astrocyte axis: Implications for type 2 diabetic cognitive dysfunction

BACKGROUND

Diabetic cognitive dysfunction (DCD) is one of the most insidious complications of type 2 diabetes mellitus, which can seriously affect the ability to self-monitoring of blood glucose and the quality of life in the elderly. Previous pathological studies of cognitive dysfunction have focused on neuronal dysfunction, characterized by extracellular beta-amyloid deposition and intracellular tau hyperphosphorylation. In recent years, astrocytes have been recognized as a potential therapeutic target for cognitive dysfunction and important participants in the central control of metabolism. The disorder of gut microbiota and their metabolites have been linked to a series of metabolic diseases such as diabetes mellitus. The imbalance of intestinal flora has the effect of promoting the occurrence and deterioration of several diabetes-related complications. Gut microbes and their metabolites can drive astrocyte activation.

AIMS

We reviewed the pathological progress of DCD related to the "gut microbiota-astrocyte" axis in terms of peripheral and central inflammation, intestinal and blood-brain barrier (BBB) dysfunction, systemic and brain energy metabolism disorders to deepen the pathological research progress of DCD and explore the potential therapeutic targets.

CONCLUSION

"Gut microbiota-astrocyte" axis, unique bidirectional crosstalk in the brain-gut axis, mediates the intermediate pathological process of neurocognitive dysfunction secondary to metabolic disorders in diabetes mellitus.

The sodium glucose co-transporter 2 inhibitor ertugliflozin for Alzheimer's disease: Inhibition of brain insulin signaling disruption-induced tau hyperphosphorylation

An antidiabetic agent sodium glucose co-transporter 2 (SGLT2) inhibitor ertugliflozin has been revealed to bind to catalytic anionic site of acetylcholinesterase (AChE), which is considered to be associated with the cognitive decline in neurodegenerative diseases, such as Alzheimer's disease (AD). The aim of the present study was thus to probe the effect of ertugliflozin on AD. Intracerebroventricular injection of streptozotocin (STZ/i.c.v) (3 mg/kg) was done bilaterally in male Wistar rats at 7-8 weeks of age. Two treatment doses (5 mg/kg and 10 mg/kg) of ertugliflozin were given intragastrically to STZ/i.c.v-induced rats for 20 days daily for behavioral assessment. Biochemical estimations of cholinergic activity, neuronal apoptosis, mitochondrial function and synaptic plasticity were performed. Behavioral results with ertugliflozin treatment revealed attenuation of cognitive deficit. Ertugliflozin also inhibited hippocampal AChE activity, downregulated pro-apoptotic marker expression, as well as mitigated mitochondrial dysfunction and synaptic damage in STZ/i.c.v rats. Importantly, we found that the hyperphosphorylation of tau in the hippocampus of STZ/i.c.v rats was decreased after oral administration of ertugliflozin, which was accompanied by decreased Phospho.IRS-1_Ser307/Total.IRS-1 ratio and increased Phospho.Akt_Ser473/Total.Akt and Phospho.GSK3β_Ser9/Total.GSK3β ratios. Our results indicated that treatment with ertugliflozin reversed AD pathology, which may be associated with inhibition of insulin signaling disruption-induced tau hyperphosphorylation.

Correlations between Cognitive Evaluation and Metabolic Syndrome

One of the most common medical diseases is metabolic syndrome (MetS), which encompasses diabetes and obesity. It has a systemic effect, which has long-lasting consequences on the body that are still not fully understood. The objectives of the study were to investigate the association between the severity of metabolic imbalances, insulin resistance, leptin concentration, and the presence of cognitive disorders and to assess the possible protective role of some classes of drugs used in the treatment of type 2 diabetes mellitus (T2D) and dyslipidemia in order to identify a viable target in the near future. The study included 148 diabetic patients. Standardized tests for the evaluation of cognition, including Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), were applied to all study participants. Serum concentrations of leptin and insulin were determined using the enzyme-linked immunosorbent assay method (ELISA), and insulin resistance was calculated using the homeostatic model assessment for insulin resistance (HOMA-IR). We found that MMSE and MoCA scores were associated with anthropometric parameters, and MoCA was associated with glycemic control parameters and leptin levels. Further research is needed in order to establish the magnitude of the relationship between metabolic syndrome components and cognitive decline in diabetic patients.

Diabetic vascular diseases: molecular mechanisms and therapeutic strategies

Vascular complications of diabetes pose a severe threat to human health. Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes. Diabetic panvascular disease (DPD) is a clinical syndrome in which vessels of various sizes, including macrovessels and microvessels in the cardiac, cerebral, renal, ophthalmic, and peripheral systems of patients with diabetes, develop atherosclerosis as a common pathology. Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis, as well as microvascular endothelial function impairment, basement membrane thickening, and microthrombosis. Cardiac, cerebral, and peripheral microangiopathy coexist with microangiopathy, while renal and retinal are predominantly microangiopathic. The following associations exist between DPDs: numerous similar molecular mechanisms, and risk-predictive relationships between diseases. Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment. In addition to the widely recommended metformin, glucagon-like peptide-1 agonist, and sodium-glucose cotransporter-2 inhibitors, for the latest molecular mechanisms, aldose reductase inhibitors, peroxisome proliferator-activated receptor-γ agonizts, glucokinases agonizts, mitochondrial energy modulators, etc. are under active development. DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases. This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence. Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.

Molecular and neural roles of sodium-glucose cotransporter 2 inhibitors in alleviating neurocognitive impairment in diabetic mice

Diabetes causes a variety of molecular changes in the brain, making it a real risk factor for the development of cognitive dysfunction. Complex pathogenesis and clinical heterogeneity of cognitive impairment makes the efficacy of current drugs limited. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) gained our attention as drugs with potential beneficial effects on the CNS. In the present study, these drugs ameliorated the cognitive impairment associated with diabetes. Moreover, we verified whether SGLT2i can mediate the degradation of amyloid precursor protein (APP) and modulation of gene expression (Bdnf, Snca, App) involved in the control of neuronal proliferation and memory. The results of our research proved the participation of SGLT2i in the multifactorial process of neuroprotection. SGLT2i attenuate the neurocognitive impairment through the restoration of neurotrophin levels, modulation of neuroinflammatory signaling, and gene expression of Snca, Bdnf, and App in the brain of diabetic mice. The targeting of the above-mentioned genes is currently seen as one of the most promising and developed therapeutic strategies for diseases associated with cognitive dysfunction. The results of this work could form the basis of a future administration of SGLT2i in diabetics with neurocognitive impairment.

The relationship between components of hypoglycemia worries and avoiding hypoglycemia behavior in type 2 diabetes mellitus with hypoglycemia: a network analysis

BACKGROUND

The fear of hypoglycemia in type 2 diabetes mellitus (T2DM) patients with hypoglycemia has seriously affected their quality of life. They are always afraid of hypoglycemia and often take excessive action to avoid it. Yet, researchers have investigated the relationship between hypoglycemia worries and excessive avoiding hypoglycemia behavior using total scores on self-report measures. However, network analysis studies of hypoglycemia worries and excessive avoiding hypoglycemia behavior in T2DM patients with hypoglycemia are lacking.

PURPOSE

The present study investigated the network structure of hypoglycemia worries and avoiding hypoglycemia behavior in T2DM patients with hypoglycemia and aimed to identify bridge items to help them correctly treat hypoglycemia and properly deal with hypoglycemia fear.

METHODS

A total of 283 T2DM patients with hypoglycemia were enrolled in our study. Hypoglycemia worries and avoiding hypoglycemia behavior were evaluated with the Hypoglycemia Fear Scale. Network analyses were used for the statistical analysis.

RESULTS

B9 "Had to stay at home for fear of hypoglycemia" and W12 "I am worried that hypoglycemia will affect my judgment" have the highest expected influences in the present network. In the community of hypoglycemia worries, W17 "I worry about hypoglycemia during sleep" has the highest bridge expected influence. And in the community of avoiding hypoglycemia behavior, B9 "Had to stay at home for fear of hypoglycemia" has the highest bridge expected influence.

CONCLUSION

Complex patterns of associations existed in the relationship between hypoglycemia worries and avoiding hypoglycemia behavior in T2DM patients with hypoglycemia. From the perspective of network analysis, B9 "Had to stay at home for fear of hypoglycemia" and W12 "I am worried that hypoglycemia will affect my judgment" have the highest expected influence, indicating their highest importance in the network. W17 "I worry about hypoglycemia during sleep" aspect of hypoglycemia worries and B9 "Had to stay at home for fear of hypoglycemia" aspect of avoiding hypoglycemia behavior have the highest bridge expected influence, indicating they have the strongest connections with each community. These results have important implications for clinical practice, which provided potential targets for interventions to reduce hypoglycemia fear and improve the quality of life in T2DM patients with hypoglycemia.

The Effect of the Sodium—Glucose Cotransporter Inhibitor on Cognition and Metabolic Parameters in a Rat Model of Sporadic Alzheimer’s Disease

Type 2 diabetes mellitus increases the risk of sporadic Alzheimer’s disease (sAD), and antidiabetic drugs, including the sodium–glucose cotransporter inhibitors (SGLTI), are being studied as possible sAD therapy. We have explored whether the SGLTI phloridzin may influence metabolic and cognitive parameters in a rat model of sAD. Adult male Wistar rats were randomized to a control (CTR), an sAD-model group induced by intracerebroventricular streptozotocin (STZ-icv; 3 mg/kg), a CTR+SGLTI, or an STZ-icv+SGLTI group. Two-month-long oral (gavage) SGLTI treatment (10 mg/kg) was initiated 1 month after STZ-icv and cognitive performance tested prior to sacrifice. SGLTI treatment significantly decreased plasma glucose levels only in the CTR group and failed to correct STZ-icv-induced cognitive deficit. In both the CTR and STZ-icv groups, SGLTI treatment diminished weight gain, decreased amyloid beta (Aβ) 1-42 in duodenum, and decreased the plasma levels of total glucagon-like peptide 1 (GLP-1), while the levels of active GLP-1, as well as both total and active glucose-dependent insulinotropic polypeptide, remained unchanged, compared to their respective controls. The increment in GLP-1 levels in the cerebrospinal fluid and its effect on Aβ 1-42 in duodenum could be one of the molecular mechanisms by which SGLTIs indirectly induce pleiotropic beneficial effects.

Unlocking the Full Potential of SGLT2 Inhibitors: Expanding Applications beyond Glycemic Control

The number of diabetic patients has risen dramatically in recent decades, owing mostly to the rising incidence of type 2 diabetes mellitus (T2DM). Several oral antidiabetic medications are used for the treatment of T2DM including, α-glucosidases inhibitors, biguanides, sulfonylureas, meglitinides, GLP-1 receptor agonists, PPAR-γ agonists, DDP4 inhibitors, and SGLT2 inhibitors. In this review we focus on the possible effects of SGLT2 inhibitors on different body systems. Beyond the diabetic state, SGLT2 inhibitors have revealed a demonstrable ability to ameliorate cardiac remodeling, enhance myocardial function, and lower heart failure mortality. Additionally, SGLT2 inhibitors can modify adipocytes and their production of cytokines, such as adipokines and adiponectin, which enhances insulin sensitivity and delays diabetes onset. On the other hand, SGLT2 inhibitors have been linked to decreased total hip bone mineral deposition and increased hip bone resorption in T2DM patients. More data are needed to evaluate the role of SGLT2 inhibitors on cancer. Finally, the effects of SGLT2 inhibitors on neuroprotection appear to be both direct and indirect, according to scientific investigations utilizing various experimental models. SGLT2 inhibitors improve vascular tone, elasticity, and contractility by reducing oxidative stress, inflammation, insulin signaling pathways, and endothelial cell proliferation. They also improve brain function, synaptic plasticity, acetylcholinesterase activity, and reduce amyloid plaque formation, as well as regulation of the mTOR pathway in the brain, which reduces brain damage and cognitive decline.

Efficacy and safety profile of SGLT2 inhibitors in the elderly: How is the benefit/risk balance?

Type 2 diabetes mellitus (T2DM) is a highly prevalent health condition in the aging population. Older adults with T2DM have higher risks of cardiovascular disease, heart failure (long underestimated) and premature death than those without diabetes. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have proven their ability to improve cardiovascular prognosis and reduce the risk of hospitalization for heart failure (hHF). However, several adverse events have been reported, whose incidence and severity might be increased in the elderly population. The aims of this comprehensive review were to analyze the benefit-risk ratio of SGLT2i therapy in older patients with T2DM by collecting data from (i) large prospective placebo-controlled cardiovascular outcome trials (including those dedicated to heart failure), using both original publications and dedicated post-hoc analyses across different age groups and (ii) observational cohort studies, describing the effects of SGLT2is versus other glucose-lowering agents on cardiovascular outcomes and hHF in elderly patients or these effects in different age groups. Overall, consistent results showed a similar relative risk reduction in cardiovascular mortality and hHF with SGLT2is independently of age. The absolute risk reduction may be greater in elderly because of a higher background risk in older versus younger patients. Similarly, the safety profile of SGLT2is appeared comparable in older versus younger patients. In conclusion, the benefit/risk balance favors the use of SGLT2is in older patients at risk of cardiovascular disease and/or heart failure. Caution may be required in very old frail patients, especially those exposed to an increased risk of volume depletion.

Metabolic Syndrome as a Risk Factor for Alzheimer's Disease: A Focus on Insulin Resistance

Alzheimer's disease (AD) is the main type of dementia and is a disease with a profound socioeconomic burden due to the lack of effective treatment. In addition to genetics and environmental factors, AD is highly associated with metabolic syndrome, defined as the combination of hypertension, hyperlipidemia, obesity and type 2 diabetes mellitus (T2DM). Among these risk factors, the connection between AD and T2DM has been deeply studied. It has been suggested that the mechanism linking both conditions is insulin resistance. Insulin is an important hormone that regulates not only peripheral energy homeostasis but also brain functions, such as cognition. Insulin desensitization, therefore, could impact normal brain function increasing the risk of developing neurodegenerative disorders in later life. Paradoxically, it has been demonstrated that decreased neuronal insulin signalling can also have a protective role in aging and protein-aggregation-associated diseases, as is the case in AD. This controversy is fed by studies focused on neuronal insulin signalling. However, the role of insulin action on other brain cell types, such as astrocytes, is still unexplored. Therefore, it is worthwhile exploring the involvement of the astrocytic insulin receptor in cognition, as well as in the onset and/or development of AD.

Type 2 diabetes mellitus and cognitive function: understanding the connections

PURPOSE OF REVIEW

To review the connection between type 2 diabetes and cognitive dysfunction, including its epidemiology, potential mechanisms of pathophysiology, risk factors, possible prevention, and treatment considerations.

RECENT FINDINGS

Diabetes is a risk factor for mild cognitive decline, in addition to Alzheimer's disease and vascular dementia. Duration of diabetes, concomitant vascular or associated co-morbidities, hyper- and hypoglycemia may lead to worsening cognitive dysfunction. Unfortunately, there is a lack of evidence-based guidance on the prevention of cognitive dysfunction in the diabetes population. Studies of diabetes medications, including metformin, glucagon-like peptide-1 (GLP-1) receptor agonists, and sodium-glucose cotransporter-2 inhibitors (SGLT2) have shown some benefit with cardiovascular morbidity and may affect cognition. In the absence of clearly defined preventive tools, diabetes practice guidelines recommend annual cognitive screening as standard of care in adults with diabetes aged 65 years or older.

SUMMARY

People living with diabetes are at risk for significant decline in cognitive function. Epidemiology and risk factors are well defined. Prevention and treatment strategies are limited and require further study.

Atrial fibrillation: Epigenetic aspects and role of sodium-glucose cotransporter 2 inhibitors

Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with substantial morbidity and mortality. Pathophysiological aspects consist in the activation of pro-fibrotic signaling and Ca²⁺ handling abnormalities at atrial level. Structural and electrical remodeling creates a substrate for AF by triggering conduction abnormalities and cardiac arrhythmias. The care of AF patients focuses predominantly on anticoagulation, symptoms control and the management of risk factors and comorbidities. The goal of AF therapy points to restore sinus rhythm, re-establish atrioventricular synchrony and improve atrial contribution to the stroke volume. New layer of information to better comprehend AF pathophysiology, and identify targets for novel pharmacological interventions consists of the epigenetic phenomena including, among others, DNA methylation, histone modifications and noncoding RNAs. Moreover, the benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in diabetic and non-diabetic patients at cardiovascular risk as well as emerging evidence on the ability of SGLT2i to modify epigenetic signature in cardiovascular diseases provide a solid background to investigate a possible role of this drug class in the onset and progression of AF. In this review, following a summary of pathophysiology and management, epigenetic mechanisms in AF and the potential of sodium-glucose SGLT2i in AF patients are discussed.

Association of Sodium-Glucose Cotransporter 2 Inhibitors With Time to Dementia: A Population-Based Cohort Study

OBJECTIVE

Type 2 diabetes (T2D) increases dementia risk, but clear evidence to recommend interventions that can mitigate that risk remains lacking. This population-based retrospective cohort study aimed to determine whether new use of sodium-glucose cotransporter 2 (SGLT2) inhibitors compared with dipeptidyl peptidase 4 (DPP-4) inhibitors was associated with lower dementia risk.

RESEARCH DESIGN AND METHODS

Ontario residents aged ≥66 years who were new users of an SGLT2 inhibitor or a DPP-4 inhibitor from 1 July 2016 to 31 March 2021 entered the cohort. Incident dementia was identified using a validated algorithm for Alzheimer's disease and related dementias. Propensity score-weighted Cox proportional hazards models were used to obtain adjusted hazard ratios (aHR) and CIs for time to incident dementia. To address reverse causality and disease latency, the observation window started at 1-year lag time from cohort entry. The primary analysis followed intention-to-treat exposure definition, and a secondary as-treated analysis was performed.

RESULTS

Among 106,903 individuals, SGLT2 inhibitors compared with DPP-4 inhibitors were associated with lower risk of dementia (14.2/1,000 person-years; aHR 0.80 [95% CI 0.71-0.89]) over a mean follow-up of 2.80 years from cohort entry. When stratified by different SGLT2 inhibitors, dapagliflozin exhibited the lowest risk (aHR 0.67 [95% CI 0.53-0.84]), followed by empagliflozin (aHR 0.78 [95% CI 0.69-0.89]), whereas canagliflozin showed no association (aHR 0.96 [95% CI 0.80-1.16]). The as-treated analysis observed a larger association (aHR 0.66 [95% CI 0.57-0.76]) than the intention-to-treat analysis.

CONCLUSIONS

SGLT2 inhibitors showed an association with lower dementia risk in older people with T2D. Randomized controlled trials are warranted.

Insulin resistance in Alzheimer's disease: The genetics and metabolomics links

Alzheimer's disease (AD) is a neurodegenerative disease with significant socioeconomic burden worldwide. Although genetics and environmental factors play a role, AD is highly associated with insulin resistance (IR) disorders such as metabolic syndrome (MS), obesity, and type two diabetes mellitus (T2DM). These findings highlight a shared pathogenesis. The use of metabolomics as a downstream systems' biology (omics) approach can help to identify these shared metabolic traits and assist in the early identification of at-risk groups and potentially guide therapy. Targeting the shared AD-IR metabolic trait with lifestyle interventions and pharmacological treatments may offer promising AD therapeutic approach. In this narrative review, we reviewed the literature on the AD-IR pathogenic link, the shared genetics and metabolomics biomarkers between AD and IR disorders, as well as the lifestyle interventions and pharmacological treatments which target this pathogenic link.

Perceptions and responses to cognitive decline in people with diabetes: A systematic review of qualitative studies

Objective

We aimed at summarizing the perceptions and responses to cognitive decline, assessing the disease management, identifying deficiencies and proposing new strategies for improvement in people with diabetes (PWDs).

Methods

A comprehensive search was performed in the following nine databases: PubMed, EMBASE, Web of Science, The Cochrane Library, PsycINFO, CINAHL, WanFang, CNKI, and VIP. The Joanna Briggs Institute (JBI) Critical Appraisal Tool for qualitative research was utilized to evaluate the quality of included studies. Descriptive texts and quotations relating to patient experience were extracted from the included studies and thematically analyzed.

Results

Eight qualitative studies met the inclusion criteria and 2 overarching themes were identified: (1) self-perception of cognitive decline referred to perceived cognitive symptoms, lack of knowledge and, impaired self-management and coping in multiple methods; (2) reported benefits of cognitive interventions referred to how cognitive interventions improved disease management, attitudes and needs of PWDs.

Conclusion

PWDs described misconceptions about their cognitive decline and suffered from them during disease management. This study provides a patient-specific reference for cognitive screening and intervention in PWDs, supporting disease management with cognitive decline in clinical practice.

DISC1 inhibits GSK3β activity to prevent tau hyperphosphorylation under diabetic encephalopathy

Diabetic encephalopathy (DE) is a common complication of type 2 diabetes (T2D), especially in those patients with long T2D history. Persistent high glucose (HG) stimulation leads to neuron damage and manifests like Alzheimer's disease's pathological features such as neurofilament tangle. However, the precise mechanism of high-glucose-induced tau hyperphosphorylation is not fully revealed. We here gave evidence that Disrupted in schizophrenia 1 protein (DISC1) could interact with glycogen synthase kinase 3β (GSK3β) and inhibit its activity to prevent tau hyperphosphorylation. By using DB/DB mice as animal model and HG-treated N2a cell as cell model, we found that DISC1 was downregulated both in vivo and in vitro, complicated with Tau hyperphosphorylation and GSK3β activation. Further, we identified DISC1 interacted with GSK3β by its 198th-237th amino acid residues. Overexpression of full length DISC1 but not mutated DISC1 lacking this domain could prevent HG induced tau hyperphosphorylation. Taken together, our work revealed DISC1 could be an important negative modulators of tau phosphorylation, and suggested that preservation of DISC1 could prevent HG induced neuron damage.

Sodium-Glucose Cotransporter-2 Inhibition Exacerbates Hepatic Encephalopathy in Biliary Cirrhotic Rats

In liver cirrhosis, hepatic inflammation and abundant portal-systemic collaterals are indicated for the development of hepatic encephalopathy. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are a type of anti-diabetic agent which exert pleiotropic and anti-inflammatory effects. Diabetes and chronic liver disease often coexist, but the influence of SGLT-2 inhibition on liver cirrhosis and hepatic encephalopathy remains unknown. This study investigated the effect of SGLT-2 inhibition on cirrhotic rats. Biliary cirrhosis was induced in Sprague-Dawley rats via common bile duct ligation. A total of two weeks of treatment with the SGLT-2 inhibitor, empagliflozin 30 mg/kg/d, was applied. The motor activities, hemodynamics, biochemistry parameters, plasma levels of vascular endothelial growth factor (VEGF), and the severity of portal-systemic collateral shunts were measured. The hepatic histopathology and protein expressions were examined. We found that empagliflozin treatment did not affect hemodynamics, liver biochemistry, or blood glucose levels in cirrhotic rats. Empagliflozin did not affect hepatic inflammation and fibrosis. The protein expression of factors related to liver injury were not influenced by empagliflozin. However, empagliflozin decreased motor activities in cirrhotic rats and increased portal-systemic collateral shunts and VEGF plasma levels. In summary, SGLT-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy, which was evidenced by a decrease in motor activity. A possible mechanism could be an increase of portal-systemic shunts related to VEGF upregulation. Therefore, empagliflozin use should be cautious in cirrhotic patients regarding the development of hepatic encephalopathy. SIGNIFICANCE STATEMENT: Sodium-glucose cotransporter-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy through increased portal-systemic shunts related to VEGF up-regulation.

Neurovascular coupling in patients with type 2 diabetes mellitus

Functional and metabolic neural changes in Type 2 diabetes mellitus (T2DM) can be associated with poor cognitive performances. Here we analyzed the functional-metabolic neurovascular coupling (NVC) in the brain of T2DM patients. Thirty-three patients (70 ± 6 years, 15 males) with recent T2DM diagnosis and 18 healthy control (HC) subjects (65 ± 9 years, 9 males) were enrolled in a brain MRI study to identify the potential effects of T2DM on NVC. T2DM patients were either drug-naive (n = 19) or under treatment with metformin (n = 14) since less than 6 months. Arterial spin labeling and blood oxygen level dependent resting-state functional MRI (RS-fMRI) images were combined to derive NVC measures in brain regions and large-scale networks in a standard brain parcelation. Altered NVC values in T2DM patients were correlated with cognitive performances spanning several neurological domains using Spearman correlation coefficients. Compared to HC, T2DM patients had reduced NVC in the default mode network (DMN) and increased NVC in three regions of the dorsal (DAN) and salience-ventral (SVAN) attention networks. NVC abnormalities in DAN and SVAN were associated with reduced visuo-spatial cognitive performances. A spatial pattern of NVC reduction in the DMN, accompanied by isolated regional NVC increases in DAN and SVAN, could reflect the emergence of (defective) compensatory processes in T2DM patients in response to altered neurovascular conditions. Overall, this pattern is reminiscent of neural abnormalities previously observed in Alzheimer’s disease, suggesting that similar neurobiological mechanisms, secondary to insulin resistance and manifesting as NVC alterations, might be developing in T2DM pathology.

Glucose-lowering drugs, cognition, and dementia: The clinical evidence

Type 2 diabetes mellitus (T2DM) is an important risk factor for dementia. The possibility to mitigate this risk by controlling T2DM is compelling; however, different glucose-lowering drugs have different effects on the brain by virtue of their different mechanisms of action. The clinical and epidemiological data appear mixed, warranting careful critical evaluation of the human studies. Here we examine the evidence in the context of dementia prevention and treatment, both for people with and without T2DM. We discuss the evidence on this scaffold of research directions, identifying methodological complexities in the extant literature (e.g. comparator discrepancies, changes in the therapeutic landscape), and the implications of different outcome measures (e.g. neuropsychological). We consider possible implications of cerebrovascular protection vs. effects on progression of neurodegenerative proteinopathy, and we present a research roadmap for glucose-lowering drugs in cognitive neurology, including neuroimaging, and fluid biomarkers. We conclude that there is great potential to advance personalized strategies to prevent and treat dementia with glucose-lowering drugs.