The effects of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide 1 receptor agonists on cognitive functions in adults with type 2 diabetes mellitus: a systematic review and meta-analysis

Sodium-glucose cotransporter-2 inhibitors and their potential role in dementia onset and cognitive function in patients with diabetes mellitus: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to determine the association between the use of sodium-glucose cotransporter 2 (SGLT-2) inhibitors and dementia onset as well as cognitive function in patients with diabetes mellitus. We comprehensively searched the MEDLINE, Embase, and CENTRAL databases to select relevant studies published up to August 2023. The use of SGLT-2 inhibitors significantly lowers dementia risk compared to SGLT-2i non-users (Hazard ratio: 0.68, 95 % CI: 0.50-0.92). Furthermore, our findings indicated a positive effect of SGLT-2 inhibitor use on cognitive function score improvement, as demonstrated by the standardized mean difference of 0.88 (95 % CI: 0.32-1.44), particularly among populations with mild cognitive impairment or dementia. This systematic review and meta-analysis indicate a potential role of SGLT-2 inhibitors in reducing the risk of dementia in patients with diabetes mellitus. These findings underscore the need for well-controlled large clinical trials and future research in this field.

Current perspectives on prevention of vascular cognitive impairment and promotion of vascular brain health

INTRODUCTION

The true global burden of vascular cognitive impairment (VCI) is unknown. Reducing risk factors for stroke and cardiovascular disease would inevitably curtail VCI.

AREAS COVERED

The authors review current diagnosis, epidemiology, and risk factors for VCI. VCI increases in older age and by inheritance of known genetic traits. They emphasize modifiable risk factors identified by the 2020 Lancet Dementia Commission. The most profound risks for VCI also include lower education, cardiometabolic factors, and compromised cognitive reserve. Finally, they discuss pharmacological and non-pharmacological interventions.

EXPERT OPINION

By virtue of the high frequencies of stroke and cardiovascular disease the global prevalence of VCI is expectedly higher than prevalent neurodegenerative disorders causing dementia. Since ~ 90% of the global burden of stroke can be attributed to modifiable risk factors, a formidable opportunity arises to reduce the burden of not only stroke but VCI outcomes including progression from mild to the major in form of vascular dementia. Strict control of vascular risk factors and secondary prevention of cerebrovascular disease via pharmacological interventions will impact on burden of VCI. Non-pharmacological measures by adopting healthy diets and encouraging physical and cognitive activities and urging multidomain approaches are important for prevention of VCI and preservation of vascular brain health.

Cognitive protection of incretin-based therapies in patients with type 2 diabetes mellitus: A systematic review and meta-analysis based on clinical studies

AIMS/INTRODUCTION

Cognitive dysfunction, including mild cognitive impairment and dementia, is increasingly recognized as an important complication of type 2 diabetes mellitus. The aims of the preset study was to investigate the cognitive protection of incretin-based therapies, including glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane library, Web of Science and PsycINFO were searched from the inception through 17 January 2023 for randomized controlled trials and cohort studies on the association between incretin-based therapies and cognitive function. A total of 15 studies were finally included in our systematic review, and eight of which were incorporated into our meta-analysis.

RESULTS

Pooled results showed that the Mini-Mental State Examination score in incretin-based therapy groups was increased by 1.20 compared with the control group (weighted mean difference 1.20, 95% confidence interval 0.39-2.01). The results of eight studies assessed by the Newcastle Ottawa Quality Assessment Scale and the Cochrane Collaboration's tool, and the quality of the eight studies were at a relatively high level. Egger's regression did not show significant publication bias.

CONCLUSIONS

Current evidence shows that incretin-based therapies might be more effective, when compared with the other hypoglycemic drugs, for cognitive improvement in patients with type 2 diabetes mellitus.

Diabetes and cognitive function: An evidence-based current perspective

Several epidemiological studies have clearly identified diabetes mellitus (DM) as a major risk factor for cognitive dysfunction, and it is going to be a major public health issue in the coming years because of the alarming rise in diabetes prevalence across the world. Brain and neural tissues predominantly depend on glucose as energy substrate and hence, any alterations in carbohydrate meta-bolism can directly impact on cerebral functional output including cognition, executive capacity, and memory. DM affects neuronal function and mental capacity in several ways, some of which include hypoperfusion of the brain tissues from cerebrovascular disease, diabetes-related alterations of glucose transporters causing abnormalities in neuronal glucose uptake and metabolism, local hyper- and hypometabolism of brain areas from insulin resistance, and recurrent hypoglycemic episodes inherent to pharmacotherapy of diabetes resulting in neuronal damage. Cognitive decline can further worsen diabetes care as DM is a disease largely self-managed by patients. Therefore, it is crucial to understand the pathobiology of cognitive dysfunction in relation to DM and its management for optimal long-term care plan for patients. A thorough appraisal of normal metabolic characteristics of the brain, how alterations in neural metabolism affects cognition, the diagnostic algorithm for patients with diabetes and dementia, and the management and prognosis of patients when they have this dangerous combination of illnesses is imperative in this context. This evidence-based narrative with the back-up of latest clinical trial reviews elaborates the current understanding on diabetes and cognitive function to empower physicians to manage their patients in day-to-day clinical practice.

Association between diabetes mellitus and post-stroke cognitive impairment

Stroke survivors suffer from various physical, emotional, and cognitive impairments. These changes are dynamic and depend on multiple factors, including underlying diseases, baseline brain function and pathology, the site of the stroke and the post-stroke inflammation, neurogenesis as well as the subsequent remodeling of the neuro-network. First we review the structural and pathological changes of the brain in stroke survivors with diabetes mellitus, which may lead to post-stroke cognitive dysfunction. Second, we provide evidence of hyperglycemia, diabetes mellitus, hypoglycemia, and their relationship with post-stroke cognitive impairment (PSCI) and post-stroke dementia (PSD). In addition to conventional biomarkers, such as HbA1c, we also provide other novel tools to predict PSCI/PSD, such as glycemic variability, receptor for advanced glycation end products, and gut microbiota. Finally, we attempt to provide some modifying methods for glycemic control, focusing on the prevention of PSCI/PSD.

Liraglutide improved the cognitive function of diabetic mice via the receptor of advanced glycation end products down-regulation

Background and aims Advanced glycation end products (AGEs) and receptor of advanced glycation end products (RAGE), are associated with cognition decline. We aim to investigate the effect of liraglutide on cognitive function in diabetic mice.

Results Diabetic mice showed decreased cognitive function. Moreover, lower glucagon like peptide-1 (GLP-1) levels in plasma were detected in db/db mice. Additionally, up-regulated RAGE and down-regulated glucagon like peptide-1 (GLP-1R) levels were observed in db/db mice. However, decreased GLP-1R and increased RAGE were reversed by liraglutide. We also found decreased cellular activity in cells with AGEs. Moreover, AGEs up-regulated RAGE in PC12 and HT22 cells. However, liraglutide improved the cell activity damaged by AGEs. Although we did not discover the direct-interaction between RAGE and GLP-1R, elevated RAGE levels induced by AGEs were restored by liraglutide.

Conclusion We demonstrated that the cognitive function of diabetic mice was improved by liraglutide via the down-regulation of RAGE.

Methods db/db mice and db/m mice were used in this study. Liraglutide was used to remedy diabetic mice. Neurons and RAGE in hippocampus were shown by immunofluorescence. And then, PC12 cells or HT22 cells with AGEs were treated with liraglutide. GLP-1R and RAGE were measured by western blotting.