GLP-1 mimetics and cognition

Pharmacovigilance analysis of neurological adverse events associated with GLP-1 receptor agonists based on the FDA Adverse Event Reporting System

We conducted a disproportionality analysis of the FDA Adverse Event Reporting System (FAERS) database (2005 Q2-2024 Q3) to evaluate neurological adverse events (NAEs) associated with six glucagon-like peptide-1 receptor agonists (GLP-1 RAs): exenatide, liraglutide, lixisenatide, dulaglutide, semaglutide, and tirzepatide. Among 28,953 NAE reports associated with GLP-1 RAs, 19 distinct NAE signals were identified using reporting odds ratios (RORs), including dizziness, tremor, dysgeusia, lethargy, taste disorder, presyncope, parosmia, allodynia, and hypoglycemic unconsciousness, etc. Time-to-onset analysis revealed a median latency of 32 days (IQR 7-122) for GLP-1 RA-related NAEs, with 45.28% occurring within 30 days of treatment initiation. Sensitivity analyses using proportional reporting ratios (PRRs), information components (ICs), and empirical Bayes geometric means (EBGMs) confirmed robustness of these signals. While these pharmacovigilance findings underscore the need for heightened clinical vigilance, they represent associations rather than causal relationships, constrained by inherent limitations of FAERS such as reporting bias and confounding. Future prospective studies are needed to confirm these associations and clarify underlying mechanisms.

Animal models for development of anti-obesity drugs in the age of GLP-1 agents

INTRODUCTION

Obesity is a major health crisis globally, with prevalence escalating significantly in recent decades. Obesity is not merely excessive weight but is associated with myriad health complications. Ensuring the translational effectiveness of pre-clinical obesity models is paramount, and the success of GLP-1 therapies has highlighted important benchmarks for guiding drug development.

AREAS COVERED

The authors discuss the status of various animal models used for the development of anti-obesity drugs, with particular emphasis on rodent models and their validity of preclinical-to-clinical translation. They also highlight innovative animal model integration opportunities between obesity and other associated pathology. The article is based on literature searches using PubMed for content (up until February 2025).

EXPERT OPINION

The effectiveness of GLP-1 therapies in treating type 2 diabetes and obesity presents an opportunity to evaluate the translational relevance of animal models of obesity. Due to their compelling safety profiles, GLP-1(s) are being tested in a wide range of obesity-associated diseases. Optimization of the mechanistic qualities in this drug class requires the incorporation of new endpoints beyond body weight, including lean mass preservation, cardiovascular health, and anti-inflammatory activities. Finally, we are compelled by the intersection of non-obesity disease models into an obesogenic framework to understand the combinatorial effects of obesity on these other disease indications, including heart failure, neurodegenerative diseases, and cancer.

Protective effect of Dulaglutide, a GLP1 agonist, on acetic acid-induced ulcerative colitis in rats: involvement of GLP-1, TFF-3, and TGF-β/PI3K/NF-κB signaling pathway

A chronic inflammatory condition of the colon called ulcerative colitis (UC) is characterized by mucosal surface irritation that extends from the rectum to the near proximal colon portions. The rationale of this work was to conclude if dulaglutide (Dula) could protect rats from developing colitis caused by exposure to acetic acid (AA). Rats were randomly divided into seven groups (each with eight rats): Normal control, Dula control, AA (received 2 milliliters of 3% v/v AA through the rectum), Sulfasalazine (SLZ); given SLZ (100 mg/kg) orally from day 11 to day 21 then AA intrarectally on day 22 and Dula groups ( pretreated with 50, 100 or 150 μg/kg subcutaneous injection of Dula - once weekly for three weeks and AA on day 22 to induce ulcerative colitis, colon tissues and blood samples were taken on day 23. By generating colonic histological deviations such as inflammatory processes, goblet cell death, glandular hyperplasia, and mucosa ulcers, Dula dropped AA-induced colitis. Additionally, these modifications diminished blood lactate dehydrogenase (LDH), C-reactive protein (CRP), colon weight, and the weight/length ratio of the colon. In addition, Dula decreased the oxidative stress biomarker malondialdehyde (MDA) and increased the antioxidant enzymes (total antioxidant capacity (TAC), reduced glutathione (GSH), and superoxide dismutase (SOD) concentrations). Dula also significantly reduced the expression of transforming growth factor-1 (TGF-β1), phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT) signaling pathway, and the inflammatory cytokines: nuclear factor kappa B (NF-κB), interleukin-6 (IL-6), and interferon-γ (IFN-γ) in colonic cellular structures. In addition, Dula enforced the levels of glucagon-like peptide-1 (GLP-1) and trefoil factor-3 (TFF-3) that were crucial to intestinal mucosa regeneration and healing of wounds. By modulating TGF-β1 in conjunction with other inflammatory pathways like PI3K/AKT and NF-κB, regulating the oxidant/antioxidant balance, and improving the integrity of the intestinal barrier, Dula prevented AA-induced colitis in rats.

Cardioprotective Glucose-Lowering Agents and Dementia Risk: A Systematic Review and Meta-Analysis

Importance

Although diabetes is a risk factor for dementia, the effect of glucose-lowering therapy for prevention of incident dementia is uncertain.

Objective

To determine whether cardioprotective glucose-lowering therapy (sodium-glucose cotransporter-2 inhibitors [SGLT2is], glucagon-like peptide-1 receptor agonists [GLP-1RAs], metformin, and pioglitazone), compared with controls, was associated with a reduction in risk of dementia or cognitive impairment, and among primary dementia subtypes.

Data Sources

The PubMed and Embase databases were searched for studies published from inception of the database to July 11, 2024.

Study Selection

Randomized clinical trials comparing cardioprotective glucose-lowering therapy with controls that reported dementia or change in cognitive scores. Cardioprotective glucose-lowering therapies were defined as drug classes recommended by guidelines for reduction of cardiovascular events, based on evidence from phase III randomized clinical trials. Inclusion criteria were assessed independently and inconsistencies were resolved by consensus.

Data Extraction and Synthesis

Data were screened and extracted independently by 2 authors adhering to the PRISMA guidelines in August 2024. Random-effects meta-analysis models were used to estimate a pooled treatment effect.

Main Outcomes and Measures

The primary outcome measure was dementia or cognitive impairment. The secondary outcomes were primary dementia subtypes, including vascular and Alzheimer dementia, and change in cognitive scores.

Results

Twenty-six randomized clinical trials were eligible for inclusion (N = 164 531 participants), of which 23 trials (n = 160 191 participants) reported the incidence of dementia or cognitive impairment, including 12 trials evaluating SGLT2is, 10 trials evaluating GLP-1RAs, and 1 trial evaluating pioglitazone (no trials of metformin were identified). The mean (SD) age of trial participants was 64.4 (3.5) years and 57 470 (34.9%) were women. Overall, cardioprotective glucose-lowering therapy was not significantly associated with a reduction in cognitive impairment or dementia (odds ratio [OR], 0.83 [95% CI, 0.60-1.14]). Among drug classes, GLP-1RAs were associated with a statistically significant reduction in dementia (OR, 0.55 [95% CI, 0.35-0.86]), but not SGLT2is (OR, 1.20 [95% CI, 0.67-2.17]; P value for heterogeneity = .04).

Conclusions and Relevance

While cardioprotective glucose-lowering therapies were not associated with an overall reduction in all-cause dementia, this meta-analysis of randomized clinical trials found that glucose lowering with GLP-1RAs was associated with a statistically significant reduction in all-cause dementia.

Metabolic syndrome in patients with schizophrenia: Underlying mechanisms and therapeutic approaches (Review)

Schizophrenia (SCZ) represents a considerable health concern, not only due to its impact on cognitive and psychiatric domains, but also because of its association with metabolic abnormalities. Individuals with SCZ face an increased risk of developing metabolic syndrome (MS), which contributes to the increased cardiovascular burden and reduced life expectancy observed in this population. Metabolic alterations are associated with both the SCZ condition itself and extrinsic factors, particularly the use of antipsychotic medications. Additionally, the link between SCZ and MS seems to be guided by distinct genetic parameters. The present narrative review summarizes the relationship between SCZ and MS and emphasizes the various therapeutic approaches for managing its components in patients with these conditions. Recommended therapeutic approaches include lifestyle modifications as the primary strategy, with a focus on behavioral lifestyle programs, addressing dietary patterns and physical activity. Pharmacological interventions include administering common antidiabetic medications and the selection of less metabolically harmful antipsychotics. Alternative interventions with limited clinical application are also discussed. Ultimately, a personalized therapeutic approach encompassing both the psychological and metabolic aspects is essential for the effective management of MS in patients with SCZ.

Trelagliptin Ameliorates Memory Decline in Diabetic Rats through the AMPK/AKT/GSK-3β Pathway in the Cerebral Cortex

Examining how hypoglycemic medications affect brain function is one of the best approaches to addressing cognitive impairment. In this study, trelagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, was utilized to assess memory loss in diabetic rats through fear conditioning tests. Trelagliptin restored fear memory in diabetic rats that had been disrupted over a relatively long period (24 h) or extended period (5 days). Moreover, trelagliptin treatment reduced the higher incidence of neuronal cell death in the cerebral cortex, as observed via Nissl or hematoxylin and eosin staining. Subsequent analyses revealed that diabetic rats exhibited elevated levels of inflammatory cytokines (p-IKKα and p-NFκB) and a trend toward oxidative damage, indicated by malondialdehyde (MDA), superoxide dismutase 2 (SOD2), and glutathione peroxidase 4 (GPX4) detection. However, administration of trelagliptin reversed these markers to baseline levels. Additionally, trelagliptin activated p-AMPK, p-AKT, and p-GSK-3β. Notably, trelagliptin upregulated the expression of postsynaptic density protein 95 (PSD95) and synaptotagmin 1 (SYT1) while downregulating amyloid precursor protein (APP) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE1). These findings suggest that trelagliptin alleviates cognitive impairment in diabetic rats, likely through AMPK-AKT-GSK-3β-mediated mitigation of oxidative stress, enhancement of synaptic plasticity, and reduction of Aβ accumulation.

NLRP3 inflammasomes pathway: a key target for Metformin

Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing 3 (NLRP3) is a signaling pathway that is involved in inflammatory cascades, cell survival and the immune response. NLRP3 is activated by cellular damage, oxidative stress, and other factors that stimulate the immune system. Stimulation of NLRP3 induces inflammatory reactions and the production of inflammatory cytokines. These inflammatory mediators are implicated in several diseases. Metformin (MET) is an anti-hyperglycemia agent that is extensively used in clinical practice worldwide due to its high efficiency, safety profile, and affordable price. MET is the only member of biguanide class that is used in clinical practice and a potent AMP-activated protein kinase (AMPK) agonist with proven anti-inflammatory characteristics. Due to its anti-inflammatory properties, MET is considered to be effective against diseases that have an inflammatory background, and the NLRP3 pathway is involved in the pathophysiology of these disorders. In this review, we have evaluated the evidence if MET can affect this pathway and its utility for future therapeutic approaches.

Impact of Glucagon-like Peptide-1 Receptor Agonists on Mental Illness: Evidence from a Mendelian Randomization Study

Emerging evidence suggests that glucagon-like peptide-1 receptor (GLP1R) agonists may have potential benefits for mental illnesses. However, their exact effects remain unclear. This study investigated the causal relationship between glucagon-like peptide-1 receptor agonist (GLP1RA) and the risk of 10 common mental illnesses, including attention deficit and hyperactivity disorder, anorexia nervosa, anxiety disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, post-traumatic stress disorder, schizophrenia, cannabis use disorder, and alcohol use disorder. We selected GLP1RA as the exposure and conducted a Mendelian randomization (MR) analysis. The cis-eQTLs of the drug target gene GLP1R, provided by eQTLGen, were used to simulate the pharmacological effects of GLP1RA. Type 2 diabetes and BMI were included as positive controls. Using data from both the Psychiatric Genomic Consortium and FinnGen, we conducted separate MR analyses for the same disease across these two independent databases. Meta-analysis was used to pool the results. We found genetic evidence suggesting a causal relationship between GLP1RA and a reduced risk of schizophrenia [OR (95% CI) = 0.84 (0.71-0.98), I2 = 0.0%, common effects model]. Further mediation analysis indicated that this effect might be unrelated to improvements in glycemic control but rather mediated by BMI. However, the findings of this study provide insufficient evidence to support a causal relationship between GLP1RA and other mental illnesses. Sensitivity analyses did not reveal any potential bias due to horizontal pleiotropy or heterogeneity in the above results (p > 0.05). This study suggests that genetically proxied activation of glucagon-like peptide-1 receptor is associated with a lower risk of schizophrenia. GLP1R is implicated in schizophrenia pathogenesis, and its agonists may exert potential benefits through weight management. Our study provides useful information for understanding the neuropsychiatric effects of GLP1RA, which may contribute to refining future research designs and guiding clinical management. Moreover, our findings could have significant implications for overweight individuals at high risk of schizophrenia when selecting weight-loss medications. Future research should further investigate the potential mechanisms underlying the relationship between GLP1RA and schizophrenia.

Effect and mechanism of GLP-1 on cognitive function in diabetes mellitus

Background

Diabetes mellitus (DM) is a metabolic disorder associated with cognitive impairment. Glucagon-like peptide-1 (GLP-1) and its receptor (GLP-1R) have shown neuroprotective effects.

Scope of review

This review explores the impact of DM on cognitive function. Diabetes-related cognitive impairment is divided into three stages: diabetes-associated cognitive decrements, mild cognitive impairment (MCI), and dementia. GLP-1R agonists (GLP-1RAs) have many functions, such as neuroprotection, inhibiting infection, and metabolic regulation, and show good application prospects in improving cognitive function. The mechanisms of GLP-1RAs neuroprotection may be interconnected, warranting further investigation. Understanding these mechanisms could lead to targeted treatments for diabetes-related cognitive dysfunction.

Major conclusions

Therefore, this paper reviewed the regulatory effects of GLP-1 on cognitive dysfunction and its possible mechanism. Further research is required to fully explore the potential of GLP-1 and its analogs in this context.

The role of the intestinal microbiome in cognitive decline in patients with kidney disease

Cognitive decline is frequently seen in patients with chronic kidney disease (CKD). The causes of cognitive decline in these patients are likely to be multifactorial, including vascular disease, uraemic toxins, blood-brain barrier leakage, and metabolic and endocrine changes. Gut dysbiosis is common in patients with CKD and contributes to the increase in uraemic toxins. However, the gut microbiome modulates local and systemic levels of several metabolites such as short-chain fatty acids or derivatives of tryptophan metabolism, neurotransmitters, endocannabinoid-like mediators, bile acids, hormones such as glucagon-like peptide 1 (GLP1) or cholecystokinin (CCK). These factors can affect gut function, immunity, autonomic nervous system activity and various aspects of brain function. Key areas include blood-brain barrier integrity, nerve myelination and survival/proliferation, appetite, metabolism and thermoregulation, mood, anxiety and depression, stress and local inflammation. Alterations in the composition of the gut microbiota and the production of biologically active metabolites in patients with CKD are well documented and are favoured by low-fiber diets, elevated urea levels, sedentary lifestyles, slow stool transit times and polypharmacy. In turn, dysbiosis can modulate brain function and cognitive processes, as discussed in this review. Thus, the gut microbiome may contribute to alterations in cognition in patients with CKD and may be a target for therapeutic interventions using diet, prebiotics and probiotics.

GLP-1 mimetics and diabetic ketoacidosis: possible interactions and clinical consequences

Diabetic ketoacidosis is a serious diabetes-related consequence that occurs in type 1 diabetes and less commonly in type 2 diabetes and is a major cause of death. It results from the metabolic consequences due to a lack of insulin secretion or impaired insulin activity in diabetes leading to dysregulated pathophysiologic pathways resulting in excessive ketone body formation. While ketone bodies are physiologic molecules, their high levels reduce the physiological pH of the blood and induce ketoacidosis, leading to increasing metabolic dysfunction. Glucagon-like peptide-1 (GLP-1) mimetics are a class of recently developed diabetes therapy that do not lead to hypoglycemic, but some reports have suggested a relationship between GLP-1 mimetics and ketogenesis. To clarify the possible interactions between GLP-1 mimetics and ketogenesis in diabetes, this review was undertaken to collate and interpret the literature.

Hepatic effects of GLP-1 mimetics in diabetic milieu: A mechanistic review of involved pathways

Patients with diabetic are at a higher risk of developing hepatic disorders compared to non-diabetic individuals. This increased risk can be attributed to the diabetic environment, which triggers and exacerbates harmful pathways involved in both diabetic complications and hepatic disorders. Therefore, it is important to consider the use of antidiabetic agents that offer benefits beyond glycemic control and have positive effects on liver tissues. Glucagon-like peptide-1 (GLP-1) mimetics are a novel class of antidiabetic medications known for their potent blood sugar-lowering effects. Emerging evidence suggests that these drugs also have favorable effects on the liver. However, the precise effects and underlying mechanisms are not yet fully understood. In this review, we aim to provide a mechanistic perspective on the liver benefits of GLP-1 mimetics and outline the mediating mechanisms involved.

Research progress on the association of insulin resistance with type 2 diabetes mellitus and Alzheimer's disease

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by insulin resistance and hyperglycemia. It is also known to be a risk factor for Alzheimer's disease (AD). Insulin plays a crucial role in regulating the body's metabolism and is responsible for activating the Phosphoinotide-3-Kinase (PI3K)/Protein Kinase B (Akt) signaling pathway. This pathway is activated when insulin binds to the insulin receptor on nerve cells, and it helps regulate the metabolism of glucose and lipids. Dysfunction in the insulin signaling pathway can lead to a decrease in brain insulin levels and insulin sensitivity, thereby inducing disruptions in insulin signal transduction and leading to disorders in brain energy metabolism. Moreover, these dysfunctions also contribute to the accumulation of β-amyloid (Aβ) deposition and the hyperphosphorylation of Tau protein, both of which are characteristic features of AD. Therefore, this article focuses on insulin resistance to reveal the complex mechanism between brain insulin resistance and AD occurrence in T2DM. On this basis, this article further summarizes the biological effects and mechanisms of antidiabetic drugs on the two diseases, aiming to provide new ideas for the discovery of drugs for the treatment of T2DM combined with AD.

IUPHAR review - Glucagon-like peptide-1 (GLP-1) and substance use disorders: An emerging pharmacotherapeutic target

Addiction is a chronic relapsing disease with high morbidity and mortality. Treatments for addiction include pharmacological and psychosocial interventions; however, currently available medications are limited in number and efficacy. The glucagon-like-peptide-1 (GLP-1) system is emerging as a potential novel pharmacotherapeutic target for alcohol and other substance use disorders (ASUDs). In this review, we summarize and discuss the wealth of available evidence from testing GLP-1 receptor (GLP-1R) agonist medications in preclinical models and humans with ASUDs, possible mechanisms underlying the impact of GLP-1R agonists on alcohol/substance use, gaps in knowledge, and future directions. Most of the research with GLP-1R agonists has been conducted in relation to alcohol use; psychostimulants, opioids, and nicotine have also been investigated. Preclinical evidence suggests that GLP-1R agonists reduce alcohol/substance use and other related outcomes. The main proposed mechanisms are related to reward processing, stress, and cognitive function, as well as broader mechanisms related to satiety, changes in gastric motility, and glucose homeostasis. More in-depth mechanistic studies are warranted. Clinical studies have been limited and their findings have been less conclusive; however, most support the safety and potential efficacy of GLP-1R agonists in ASUD treatment. Identifying preferred compounds, as well as possible subgroups who are most responsive to GLP-1R agonists are some of the key research questions to translate the promising preclinical data into clinical settings. Several clinical trials are underway to test GLP-1R agonists in people with ASUDs.

A comprehensive assessment of the association between common drugs and psychiatric disorders using Mendelian randomization and real-world pharmacovigilance database

BACKGROUND

Medications prescribed for chronic diseases can lead to short-term neuropsychiatric symptoms, but their long-term effects on brain structures and psychiatric conditions remain unclear.

METHODS

We comprehensively analyzed the FDA Adverse Event Reporting System database and conducted drug target Mendelian Randomization (MR) studies on six categories of common drugs, 477 brain imaging-derived phenotypes (IDPs) and eight psychiatric disorders. Genetic instruments were extracted from expression quantitative trait loci (eQTLs) in blood, brain, and other target tissues, protein quantitative trait loci (pQTLs) in blood, and genome-wide association studies (GWAS) of hemoglobin and cholesterol. Summary statistics for brain IDPs, psychiatric disorders, and gut microbiome were obtained from the BIG40, Psychiatric Genomics Consortium, and MiBioGen. A two-step MR and mediation analysis were employed to screen possible mediators of drug-IDP effects from 119 gut microbiota genera and identify their mediation proportions.

FINDINGS

Among 19 drug classes, six drugs were found to be associated with higher risks of psychiatric adverse events, while 11 drugs were associated with higher risks of gastrointestinal adverse events in the FAERS analysis. We identified ten drug-psychiatric disorder associations, 202 drug-IDP associations, 16 drug-microbiota associations, and four drug-microbiota-IDP causal links. For example, PPARG activation mediated HbA1c reduction caused a higher risk of bipolar disorder (BD) II. Genetically proxied GLP-1R agonists were significantly associated with an increase in the volume of the CA3-head of the right hippocampus and the area of the left precuneus cortex, both of which have been shown to correlate with cognition in previous studies.

INTERPRETATION

Common drugs may affect brain structure and risk of psychiatric disorder. Oral medications in particular may exert some of these effects by influencing gut microbiota. This study calls for greater attention to be paid to the neuropsychiatric adverse effects of drugs and encourages drug repurposing.

FUNDING

National Natural Science Foundation of China (grant No. 82330035, 82130043, 82172685, and 82001223), National Natural Science Foundation of Hunan Province (grant No. 2021SK1010), and the Science Foundation for Distinguished Young Scholars of Changsha (grant No. kq2209006).

Long-acting exenatide does not prevent cognitive decline in mild cognitive impairment: a proof-of-concept clinical trial

PURPOSE

According to preclinical evidence, GLP-1 receptor may be an actionable target in neurodegenerative disorders, including Alzheimer's disease (AD). Previous clinical trials of GLP-1 receptor agonists were conducted in patients with early AD, yielding mixed results. The aim was to assess in a proof-of-concept study whether slow-release exenatide, a long-acting GLP-1 agonist, can benefit the cognitive performance of people with mild cognitive impairment (MCI).

METHODS

Thirty-two (16 females) patients were randomized to either slow-release exenatide (n = 17; 2 mg s.c. once a week) or no treatment (n = 15) for 32 weeks. The primary endpoint was the change in ADAS-Cog11 cognitive test score at 32 weeks vs baseline. Secondary endpoints herein reported included additional cognitive tests and plasma readouts of GLP-1 receptor engagement. Statistical analysis was conducted by intention to treat.

RESULTS

No significant between-group effects of exenatide on ADAS-Cog11 score (p = 0.17) were detected. A gender interaction with treatment was observed (p = 0.04), due to worsening of the ADAS-Cog11 score in women randomized to exenatide (p = 0.018), after correction for age, scholar level, dysglycemia, and ADAS-Cog score baseline value. Fasting plasma glucose (p = 0.02) and body weight (p = 0.03) decreased in patients randomized to exenatide.

CONCLUSION

In patients with MCI, a 32-week trial with slow-release exenatide had no beneficial effect on cognitive performance.

TRIAL REGISTRATION NUMBER

NCT03881371, registered on 21 July, 2016.

Potent synergistic effects of dulaglutide and food restriction in prevention of olanzapine-induced metabolic adverse effects in a rodent model

BACKGROUND

Antipsychotics are indispensable in the treatment of severe mental illneses, however adverse metabolic effects including diabetes, weight gain, dyslipidemia, and related cardiovascular morbidity are common, and current pharmacological strategies for their management are unsatisfactory. Glucagon-like 1 peptide receptor agonists (GLP-1 RAs) are approved for the treatment of type 2 diabetes and obesity hold promise for the management of antipsychotic-associated adverse metabolic effects.

METHODS

To characterize the molecular effects and identify biomarkers for GLP-1 RA preventive treatment, Sprague-Dawley female rats were treated with long-acting formulations of the antipsychotic olanzapine and the GLP-1 RA dulaglutide for 8 days. A pair-feeding protocol evaluated the combined effects of dulaglutide and food restriction on an olanzapine-induced metabolic phenotype. Body weight and food consumption were recorded. Biochemical analysis included a lipid profile, a spectrum of gastrointestinal and adipose tissue-derived hormones, and fibroblast growth factor 21 serum levels.

RESULTS

Olanzapine induced hyperphagia, weight gain, increased serum triglycerides and HDL cholesterol. Food restriction affected the OLA-induced phenotype but not serum markers. Dulaglutide led to a modest decrease in food intake, with no effect on weight gain, and did not reverse the OLA-induced changes in serum lipid parameters. Concomitant dulaglutide and food restriction resulted in weight loss, decreased feed efficiency, and lower total and HDL cholesterol.

CONCLUSIONS

A combined strategy of dulaglutide and food restriction manifested a massive synergistic benefit. GLP-1RAs represent a promising strategy and deserve thorough future research. Our findings underline the potential importance of lifestyle intervention in addition to GLP-1 RA treatment.

Exploring the Potential Impact of GLP-1 Receptor Agonists on Substance Use, Compulsive Behavior, and Libido: Insights from Social Media Using a Mixed-Methods Approach

Glucagon-like peptide-1 (GLP-1) is involved in a range of central and peripheral pathways related to appetitive behavior. Hence, this study explored the effects of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on substance and behavioral addictions, including alcohol, caffeine, nicotine, cannabis, psychostimulants, compulsive shopping, and sex drive/libido. Data were collected from various social platforms. Keywords related to GLP-1 RAs and substance/behavioral addiction were used to extract relevant comments. The study employed a mixed-methods approach to analyze online discussions posted from December 2019 to June 2023 and collected using a specialized web application. Reddit entries were the focus here due to limited data from other platforms, such as TikTok and YouTube. A total of 5859 threads and related comments were extracted from six subreddits, which included threads about GLP-1 RAs drugs and associated brand names. To obtain relevant posts, keywords related to potential substance use and compulsive behavior were selected. Further analysis involved two main steps: (1) manually coding posts based on users' references to the potential impact of GLP-1 RAs on substance use and non-substance habits, excluding irrelevant or unclear comments; (2) performing a thematic analysis on the dataset of keywords, using AI-assisted techniques followed by the manual revision of the generated themes. Second, a thematic analysis was performed on the keyword-related dataset, using AI-assisted techniques followed by the manual revision of the generated themes. In total, 29.75% of alcohol-related; 22.22% of caffeine-related; and 23.08% of nicotine-related comments clearly stated a cessation of the intake of these substances following the start of GLP-1 RAs prescription. Conversely, mixed results were found for cannabis intake, and only limited, anecdotal data were made available for cocaine, entactogens, and dissociative drugs' misuse. Regarding behavioral addictions, 21.35% of comments reported a compulsive shopping interruption, whilst the sexual drive/libido elements reportedly increased in several users. The current mixed-methods approach appeared to be a useful tool in gaining insight into complex topics such as the effects of GLP-1 RAs on substance and non-substance addiction-related disorders; some GLP-1 RA-related mental health benefits could also be inferred from here. Overall, it appeared that GLP-1 RAs may show the potential to target both substance craving and maladaptive/addictive behaviors, although further empirical research is needed.

Anti-inflammatory benefits of semaglutide: State of the art

Individuals with diabetes often have chronic inflammation and high levels of inflammatory cytokines, leading to insulin resistance and complications. Anti-inflammatory agents are proposed to prevent these issues, including using antidiabetic medications with anti-inflammatory properties like semaglutide, a GLP-1 analogue. Semaglutide not only lowers glucose but also shows potential anti-inflammatory effects. Studies suggest it can modulate inflammatory responses and benefit those with diabetes. However, the exact mechanisms of its anti-inflammatory effects are not fully understood. This review aims to discuss the latest findings on semaglutide's anti-inflammatory effects and the potential pathways involved.

Changes in Cognitive Function Following Bariatric Surgery: An Updated Systematic Review

Since a previous systematic review published in 2016, there have been further studies investigating the association of changes in cognitive function following bariatric surgery. All studies since the original review that reported at least one element of cognitive function before and after bariatric surgery were eligible. A total of 137 additional studies were identified; 13 were included in addition to the 18 studies previously. Almost all studies reported improvements in at least one domain. Most revealed improvements were limited to a few domains and were not universal. Further findings investigated cognitive function improvement in relation to procedure choice, and mental health or quality of life post-surgery. Further high-powered studies are still necessary, but these findings support the impact of bariatric surgery on cognitive function in obesity.

Semaglutide attenuates pathological electrophysiological remodeling in diabetic cardiomyopathy via restoring Cx43 expression

BACKGROUND

Semaglutide is a relatively new anti-hyperglycemic agent that was shown to carry cardioprotective potentials. However, the exact effects of semaglutide on diabetic cardiomyopathy (DCM) and their underlining mechanism remain unclear. This study aimed to evaluate the effects of semaglutide on myocardium injury and cardiac function in DCM mice and its potential mechanisms, with emphasis on its effects on Cx43 and electrophysiological remodeling.

METHODS

C57BL/6 mice were randomly divided into four groups: control group, semaglutide group, diabetes group, and diabetes + semaglutide treatment group. Type 1 diabetes were induced by intraperitoneal injection of streptozotocin. Mice in the semaglutide intervention group were injected subcutaneously with semaglutide (0.15 mg/kg) every week for 8 weeks. The blood glucose, cardiac function, oxidative stress markers, apoptosis, expression of Sirt1, AMPK, Cx43, and electrocardiogram of mice in each group were evaluated.

RESULTS

Treatment with semaglutide alleviated glucose metabolism disorders and improved cardiac dysfunction in diabetic mice. In addition, semaglutide ameliorated the increase in oxidative stress and apoptosis in diabetic heart. Sirt1/AMPK pathway was activated after semaglutide treatment. Furthermore, diabetic mice showed reduced expression of Cx43 in the myocardium, accompanied by changes in electrocardiogram, including significantly prolonged RR, QRS, QT and QTc interval. Semaglutide treatment restored Cx43 expression and reversed the above-mentioned ECG abnormalities.

CONCLUSIONS

Our research results showed that semaglutide protected against oxidative stress and apoptosis in diabetic heart, thereby improving cardiac function and electrophysiological remodelling in DCM mice, which may attribute to activation of Sirt1/AMPK pathway and restore of Cx43 expression.

Relationship Between Diabetes Mellitus and Periodontal/Peri-Implant Disease: A Contemporaneous Review

The prevalence of diabetes mellitus (DM), a major chronic disease and a leading cause of death and disability around the world, is rising. According to the latest data, the global prevalence of DM has increased to 463 million (9.3% of adults) in 2019 and is estimated to reach 700 million by 2045. Periodontal disease, result of periodontium inflammation, is a common, chronic disease and has long been considered one of the complications of DM. Moreover, literature reflects a spectrum of conflicting viewpoints on the effect of diabetic conditions on the implant treatment strategies. The current review aims to update the recent epidemiologic evidence regarding the relationship between DM and periodontal/peri-implant disease, emphasising the effects of glycaemic control on the severity of these diseases and describing the pathobiological mechanisms underlying this association. This review's findings indicate a bidirectional relationship between DM and periodontal/peri-implant disease and that this relationship seems causal, implying that controlling these two diseases might help prevent each other's incidence. Additionally, the severity of periodontal/peri-implant disease is directly related to metabolic control. Although patients with diabetes can obtain implant success similar to those in systemically healthy individuals, an increased risk of peri-implantitis has been reported in DM patients. Therefore, the importance of glycaemic control and maintaining proper oral hygiene cannot be overstated.

Clinical Evidence for GLP-1 Receptor Agonists in Alzheimer's Disease: A Systematic Review

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia. While preclinical studies have shown benefits of glucagon-like peptide 1 receptor agonists (GLP-1 RA) in targeting core AD pathology, clinical studies are limited.

OBJECTIVE

A systematic review was performed to evaluate GLP-1 RAs in AD for their potential to target core AD pathology and improve cognition.

METHODS

Searches were conducted via three different databases (PubMed, Embase, and Cochrane Library). Search terms included Medical Subject Headings (MeSH) terms: 'glucagon-like peptide 1 receptor agonist' and 'Alzheimer's disease', as well as entry terms 'GLP-1 RA', 'AD', and three types of GLP-1 RA: 'liraglutide', 'exenatide', and 'lixisenatide'.

RESULTS

A total of 1,444 studies were screened. Six articles that met criteria were included (four randomized control trials [RCTs] and two protocol studies). Two RCTs with amyloid-β and tau biomarker endpoints did not observe an end of treatment difference between the placebo and treated groups. In three RCTs with cognitive endpoints, there was no end of treatment difference between placebo and treated groups. GLP-1 RA showed metabolic benefits, such as lower body mass index and improved glucose levels on oral glucose tolerance tests in treated groups. GLP-1 RA may mitigate the decline in cerebral glucose metabolism and show enhanced blood-brain glucose transport capacity using 18F-FDG PET, however, more data is needed.

CONCLUSIONS

GLP-1 RA therapy did not alter amyloid-β and tau biomarkers nor show improvements in cognition but showed potential metabolic and neuroprotective benefits.

Sympathetic nerve-enteroendocrine L cell communication modulates GLP-1 release, brain glucose utilization, and cognitive function

Glucose homeostasis is controlled by brain-gut communications. Yet our understanding of the neuron-gut interface in the glucoregulatory system remains incomplete. Here, we find that sympathetic nerves elevate postprandial blood glucose but restrict brain glucose utilization by repressing the release of glucagon-like peptide-1 (GLP-1) from enteroendocrine L cells. Sympathetic nerves are in close apposition with the L cells. Importantly, sympathetic denervation or intestinal deletion of the adrenergic receptor α2 (Adra2a) augments postprandial GLP-1 secretion, leading to reduced blood glucose levels and increased brain glucose uptake. Conversely, sympathetic activation shows the opposite effects. At the cellular level, adrenergic signaling suppresses calcium flux to limit GLP-1 secretion upon sugar ingestion. Consequently, abrogation of adrenergic signal results in a significant improvement in learning and memory ability. Together, our results reveal a sympathetic nerve-enteroendocrine unit in constraining GLP-1 secretion, thus providing a therapeutic nexus of mobilizing endogenous GLP-1 for glucose management and cognitive improvement.

Gut-brain communication mediates the impact of dietary lipids on cognitive capacity

Cognitive impairment, as a prevalent symptom of nervous system disorders, poses one of the most challenging aspects in the management of brain diseases. Lipids present in the cell membranes of all neurons within the brain and dietary lipids can regulate the cognition and memory function. In recent years, the advancements in gut microbiome research have enabled the exploration of dietary lipids targeting the gut-brain axis as a strategy for regulating cognition. This present review provides an in-depth overview of how lipids modulate cognition via the gut-brain axis depending on metabolic, immune, neural and endocrine pathways. It also comprehensively analyzes the effects of diverse lipids on the gut microbiota and intestinal barrier function, thereby affecting the central nervous system and cognitive capacity. Moreover, comparative analysis of the positive and negative effects is presented between beneficial and detrimental lipids. The former encompass monounsaturated fatty acids, short-chain fatty acids, omega-3 polyunsaturated fatty acids, phospholipids, phytosterols, fungal sterols and bioactive lipid-soluble vitamins, as well as lipid-derived gut metabolites, whereas the latter (detrimental lipids) include medium- or long-chain fatty acids, excessive proportions of n-6 polyunsaturated fatty acids, industrial trans fatty acids, and zoosterols. To sum up, the focus of this review is on how gut-brain communication mediates the impact of dietary lipids on cognitive capacity, providing a novel theoretical foundation for promoting brain cognitive health and scientific lipid consumption patterns.

Therapeutic effects of anti-diabetic drugs on traumatic brain injury

AIMS

In this narrative review, we have analyzed and synthesized current studies relating to the effects of anti-diabetic drugs on traumatic brain injury (TBI) complications.

METHODS

Eligible studies were collected from Scopus, Google Scholar, PubMed, and Cochrane Library for clinical, in-vivo, and in-vitro studies published on the impact of anti-diabetic drugs on TBI.

RESULTS

Traumatic brain injury (TBI) is a serious brain disease that is caused by any type of trauma. The pathophysiology of TBI is not yet fully understood, though physical injury and inflammatory events have been implicated in TBI progression. Several signaling pathways are known to play pivotal roles in TBI injuries, including Nuclear factor erythroid 2-related factor 2 (Nrf2), High mobility group box 1 protein/Nuclear factor kappa B (HMGB1/NF-κB), Adiponectin, Mammalian Target of Rapamycin (mTOR), Toll-Like Receptor (TLR), Wnt/β-catenin, Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT), Nod-like receptor protein3 (NLRP3) inflammasome, Phosphoglycerate kinase 1/Kelch-like ECH-associated protein 1 (PGK1/KEAP1)/Nrf2, and Mitogen-activated protein kinase (MAPK) . Recent studies suggest that oral anti-diabetic drugs such as biguanides, thiazolidinediones (TZDs), sulfonylureas (SUs), sodium-glucose cotransporter-2 inhibitors (SGLT2is), dipeptidyl peptidase-4 inhibitors (DPPIs), meglitinides, and alpha-glucosidase inhibitors (AGIs) could have beneficial effects in the management of TBI complications. These drugs may downregulate the inflammatory pathways and induce antioxidant signaling pathways, thus alleviating complications of TBI.

CONCLUSION

Based on this comprehensive literature review, antidiabetic medications might be considered in the TBI treatment protocol. However, evidence from clinical trials in patients with TBI is still warranted.

Metformin as a Potential Prevention Strategy for Alzheimer's Disease and Alzheimer's Disease Related Dementias

Background

Metformin is a safe and effective medication for type 2 diabetes (T2D) that has been proposed to decrease the risk of aging related disorders including Alzheimer's disease (AD) and Alzheimer's disease related disorders(ADRD).

Objective

This review seeks to summarize findings from studies examining the association of metformin with AD/ADRD related outcomes.

Methods

This is a narrative review of human studies, including observational studies and clinical trials, examining the association of metformin with cognitive and brain outcomes. We used PubMed as the main database for our literature search with a focus on English language human studies including observational studies and clinical trials. We prioritized studies published from 2013 until February 15, 2024.

Results

Observational human studies are conflicting, but those with better study designs suggest that metformin use in persons with T2D is associated with a lower risk of dementia. However, these observational studies are limited by the use of administrative data to ascertain metformin use and/or cognitive outcomes. There are few clinical trials in persons without T2D that have small sample sizes and short durations but suggest that metformin could prevent AD/ADRD. There are ongoing studies including large clinical trials with long duration that are testing the effect of metformin on AD/ADRD outcomes in persons without T2D at risk for dementia.

Conclusions

Clinical trial results are needed to establish the effect of metformin on the risk of AD and ADRD.

Glp-1 Mimetics and Autophagy in Diabetic Milieu: State-of-the-Art

The diabetic milieu is associated with cascades of pathophysiological pathways that culminate in diabetic complications and tissue injuries. Autophagy is an essential process mandatory for cell survival and tissue homeostasis by degrading damaged organelles and removing injured cells. However, it may turn into a pathological process in an aberrant mode in the diabetic and/or malignant milieu. Moreover, autophagy could serve as a promising therapeutic target for many complications related to tissue injury. Glp-1 mimetics are a class of newer antidiabetic agents that reduce blood glucose through several pathways. However, some evidence suggests that they can provide extra glycemic benefits by modulating autophagy, although there is no complete understanding of this mechanism and its underlying molecular pathways. Hence, in the current review, we aimed to provide new insights on the possible impact of Glp-1 mimetics on autophagy and consequent benefits as well as mediating pathways.

GLP-1/GIP Agonist as an Intriguing and Ultimate Remedy for Combating Alzheimer's Disease through its Supporting DPP4 Inhibitors: A Review

BACKGROUND

Alzheimer's disease (AD) is a widespread neurological illness in the elderly, which impacted about 50 million people globally in 2020. Type 2 diabetes has been identified as a risk factor. Insulin and incretins are substances that have various impacts on neurodegenerative processes. Preclinical research has shown that GLP-1 receptor agonists decrease neuroinflammation, tau phosphorylation, amyloid deposition, synaptic function, and memory formation. Phase 2 and 3 studies are now occurring in Alzheimer's disease populations. In this article, we present a detailed assessment of the therapeutic potential of GLP-1 analogues and DPP4 inhibitors in Alzheimer's disease.

AIM

This study aimed to gain insight into how GLP-1 analogues and associated antagonists of DPP4 safeguard against AD.

METHODS

This study uses terms from search engines, such as Scopus, PubMed, and Google Scholar, to explore the role, function, and treatment options of the GLP-1 analogue for AD.

RESULTS

The review suggested that GLP-1 analogues may be useful for treating AD because they have been linked to anti-inflammatory, neurotrophic, and neuroprotective characteristics. Throughout this review, we discuss the underlying causes of AD and how GLP signaling functions.

CONCLUSION

With a focus on AD, the molecular and pharmacological effects of a few GLP-1/GIP analogs, both synthetic and natural, as well as DPP4 inhibitors, have been mentioned, which are in the preclinical and clinical studies. This has been demonstrated to improve cognitive function in Alzheimer's patients.

Dipeptidyl peptidase-4 inhibitors alleviate cognitive dysfunction in type 2 diabetes mellitus

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) are commonly at high risk for developing cognitive dysfunction. Antidiabetic agents might be repurposed for targeting cognitive dysfunction in addition to modulation on glucose homeostasis. This study aimed to evaluate the impact of dipeptidyl peptidase-4 inhibitors (DPP-4i) on cognitive function in T2DM.

METHODS

PubMed, Embase, Cochrane Library and Web of Science were systematically searched from inception to September 30, 2023. Weighted mean differences were calculated using the Mantel-Haenszel (M-H) fixed or random effects model based on the degree of heterogeneity among studies. Heterogeneity was evaluated using a Chi-squared test and quantified with Higgins I2. Sensitivity analysis was performed with the leave-one-out method, and publication bias was evaluated according to Begg's and Egger's tests.

RESULTS

Six clinical trials involving 5,178 participants were included in the pooled analysis. Administration of DPP-4i generally correlated with an increase of Mini-Mental State Examination (MMSE) scores (1.09, 95% CI: 0.22 to 1.96). DPP-4i alleviated cognitive impairment in the copying skill subdomain of MMSE (0.26, 95% CI: 0.12 to 0.40). Treatment with DPP-4i also resulted in an increase of Instrumental Activities of Daily Living (IADL) scores (0.82, 95% CI: 0.30 to 1.34). However, DPP-4i produced no significant effects on Barthel Activities of Daily Living (BADL) scores (0.37, 95% CI: -1.26 to 1.99) or other test scores.

CONCLUSIONS

DPP-4i treatment favourably improved cognitive function in patients with T2DM. Further trials with larger samples should be performed to confirm these estimates and investigate the association of different DPP-4i with cognitive function among diabetic patients.

TRIAL REGISTRATION IN PROSPERO

CRD42023430873.

Semaglutide ameliorates cognition and glucose metabolism dysfunction in the 3xTg mouse model of Alzheimer's disease via the GLP-1R/SIRT1/GLUT4 pathway

Disorders of brain glucose metabolism is known to affect brain activity in neurodegenerative diseases including Alzheimer's disease (AD). Furthermore, recent evidence has shown an association between AD and type 2 diabetes. Numerous reports have found that glucagon-like peptide-1 (GLP-1) receptor agonists improve the cognitive behavior and pathological features in AD patients and animals, which may be related to the improvement of glucose metabolism in the brain. However, the mechanism by which GLP-1 agonists improve the brain glucose metabolism in AD patients remains unclear. In this study, we found that SIRT1 is closely related to expression of GLP-1R in hippocampus of 3xTg mice. Therefore, we used semaglutide, a novel GLP-1R agonist currently undergoing two phase 3 clinical trials in AD patients, to observe the effect of SIRT1 after semaglutide treatment in 3XTg mice and HT22 cells, and to explore the mechanism of SIRT1 in the glucose metabolism disorders of AD. The mice were injected with semaglutide on alternate days for 30 days, followed by behavioral experiments including open field test, new object recognition test, and Y-maze. The content of glucose in the brain was also measured by using 18FDG-PET-CT scans. We measured the expression of Aβ and tau in the hippocampus, observed the expression of GLUT4 which is downstream of SIRT1, and tested the Glucose oxidase assay (GOD-POD) and Hexokinase (HK) in HT22 cells. Here, we found in the 3xTg mouse model of AD and in cultured HT22 mouse neurons that SIRT1 signaling is involved in the impairment of glucose metabolism in AD. Semaglutide can increased the expression levels of SIRT1 and GLUT4 in the hippocampus of 3xTg mice, accompanied by an improvement in learning and memory, decreased in Aβ plaques and neurofibrillary tangles. In addition, we further demonstrated that semaglutide improved glucose metabolism in the brain of 3xTg mice in vitro, semaglutide promoted glycolysis and improved glycolytic disorders, and increased the membrane translocation of GLUT4 in cultured HT22 cells. These effects were blocked by the SIRT1 inhibitor (EX527). These findings indicate that semaglutide can regulate the expression of GLUT4 to mediate glucose transport through SIRT1, thereby improving glucose metabolism dysfunction in AD mice and cells. The present study suggests that SIRT1/GLUT4 signaling pathway may be an important mechanism for GLP-1R to promote glucose metabolism in the brain, providing a reliable strategy for effective therapy of AD.

Post-Stroke Brain Health Monitoring and Optimization: A Narrative Review

Significant advancements have been made in recent years in the acute treatment and secondary prevention of stroke. However, a large proportion of stroke survivors will go on to have enduring physical, cognitive, and psychological disabilities from suboptimal post-stroke brain health. Impaired brain health following stroke thus warrants increased attention from clinicians and researchers alike. In this narrative review based on an open timeframe search of the PubMed, Scopus, and Web of Science databases, we define post-stroke brain health and appraise the body of research focused on modifiable vascular, lifestyle, and psychosocial factors for optimizing post-stroke brain health. In addition, we make clinical recommendations for the monitoring and management of post-stroke brain health at major post-stroke transition points centered on four key intertwined domains: cognition, psychosocial health, physical functioning, and global vascular health. Finally, we discuss potential future work in the field of post-stroke brain health, including the use of remote monitoring and interventions, neuromodulation, multi-morbidity interventions, enriched environments, and the need to address inequities in post-stroke brain health. As post-stroke brain health is a relatively new, rapidly evolving, and broad clinical and research field, this narrative review aims to identify and summarize the evidence base to help clinicians and researchers tailor their own approach to integrating post-stroke brain health into their practices.

The alleviating effect and mechanism of GLP-1 on ulcerative colitis

Ulcerative Colitis (UC) is a major type of chronic inflammatory bowel disease of the colonic mucosa and exhibits progressive morbidity. The incidence and prevalence of UC is increasing worldwide. The global burden of UC, which can substantially reduce quality of life, is clearly increasing. These data highlight the need for research into prevention of UC and innovations in health-care systems to manage this complex and costly disease. Glucagon-like peptide-1 (GLP-1), a new antidiabetic drug, is used to treat Type 2 Diabetes Mellitus (T2DM). Accumulating evidence suggests that GLP-1 has additional roles other than glucose-lowering effects. Despite the abundance of GLP-1 research, studies in UC have been less consistent, especially body weight; for example, body weight, colon length, colon injury score, intestinal microbiota, remain to be studied further. To date, the molecular mechanism of the protective effect of GLP-1 on UC remains obscure. The effect of GLP-1 was studied by using a dextran sulfate sodium (DSS)-induced colitic mice and lipopolysaccharide (LPS) treated RAW264.7 cells (macrophage cell line) under in vivo and in vitro conditions, respectively. Our results indicate that GLP-1 significantly relieves ulcerative colitis as it represses the production of proinflammatory mediators. In addition, GLP-1 blocks the activation of the protein kinase B (AKT)/nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) signaling pathways. GLP-1 also alleviates DSS-induced injury to the intestinal mucosa and dysbiosis of gut microbiota. Altogether, GLP-1 has protection effect on ulcerative colitis. Thus, GLP-1 can be considered as a potential therapeutic candidate for the treatment of UC.

Antidiabetic agents as a novel treatment for Alzheimer's and Parkinson's disease

Therapeutic strategies for neurodegenerative disorders have commonly targeted individual aspects of the disease pathogenesis to little success. Neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by several pathological features. In AD and PD, there is an abnormal accumulation of toxic proteins, increased inflammation, decreased synaptic function, neuronal loss, increased astrocyte activation, and perhaps a state of insulin resistance. Epidemiological evidence has revealed a link between AD/PD and type 2 diabetes mellitus, with these disorders sharing some pathological commonalities. Such a link has opened up a promising avenue for repurposing antidiabetic agents in the treatment of neurodegenerative disorders. A successful therapeutic strategy for AD/PD would likely require a single or several agents which target the separate pathological processes in the disease. Targeting cerebral insulin signalling produces numerous neuroprotective effects in preclinical AD/PD brain models. Clinical trials have shown the promise of approved diabetic compounds in improving motor symptoms of PD and preventing neurodegenerative decline, with numerous further phase II trials and phase III trials underway in AD and PD populations. Alongside insulin signalling, targeting incretin receptors in the brain represents one of the most promising strategies for repurposing currently available agents for the treatment of AD/PD. Most notably, glucagon-like-peptide-1 (GLP-1) receptor agonists have displayed impressive clinical potential in preclinical and early clinical studies. In AD the GLP-1 receptor agonist, liraglutide, has been demonstrated to improve cerebral glucose metabolism and functional connectivity in small-scale pilot trials. Whilst in PD, the GLP-1 receptor agonist exenatide is effective in restoring motor function and cognition. Targeting brain incretin receptors reduces inflammation, inhibits apoptosis, prevents toxic protein aggregation, enhances long-term potentiation and autophagy as well as restores dysfunctional insulin signalling. Support is also increasing for the use of additional approved diabetic treatments, including intranasal insulin, metformin hydrochloride, peroxisome proliferator-activated nuclear receptor γ agonists, amylin analogs, and protein tyrosine phosphatase 1B inhibitors which are in the investigation for deployment in PD and AD treatment. As such, we provide a comprehensive review of several promising anti-diabetic agents for the treatment of AD and PD.

Strategies for Treatment of Disease-Associated Dementia Beyond Alzheimer's Disease: An Update

Memory, cognition, dementia, and neurodegeneration are complexly interlinked processes with various mechanistic pathways, leading to a range of clinical outcomes. They are strongly associated with pathological conditions like Alzheimer's disease, Parkinson's disease, schizophrenia, and stroke and are a growing concern for their timely diagnosis and management. Several cognitionenhancing interventions for management include non-pharmacological interventions like diet, exercise, and physical activity, while pharmacological interventions include medicinal agents, herbal agents, and nutritional supplements. This review critically analyzed and discussed the currently available agents under different drug development phases designed to target the molecular targets, including cholinergic receptor, glutamatergic system, GABAergic targets, glycine site, serotonergic targets, histamine receptors, etc. Understanding memory formation and pathways involved therein aids in opening the new gateways to treating cognitive disorders. However, clinical studies suggest that there is still a dearth of knowledge about the pathological mechanism involved in neurological conditions, making the dropouts of agents from the initial phases of the clinical trial. Hence, a better understanding of the disease biology, mode of drug action, and interlinked mechanistic pathways at a molecular level is required.

Benefits of GLP-1 Mimetics on Epicardial Adiposity

The epicardial adipose tissue, which is referred to as fats surrounding the myocardium, is an active organ able to induce cardiovascular problems in pathophysiologic conditions through several pathways, such as inflammation, fibrosis, fat infiltration, and electrophysiologic problems. So, control of its volume and thickness, especially in patients with diabetes, is highly important. Incretin-based pharmacologic agents are newly developed antidiabetics that could provide further cardiovascular benefits through control and modulating epicardial adiposity. They can reduce cardiovascular risks by rapidly reducing epicardial adipose tissues, improving cardiac efficiency. We are at the first steps of a long way, but current evidence demonstrates the sum of possible mechanisms. In this study, we evaluate epicardial adiposity in physiologic and pathologic states and the impact of incretin-based drugs.

Glucagon-like Peptide 1 Receptor Activation Inhibits Microglial Pyroptosis via Promoting Mitophagy to Alleviate Depression-like Behaviors in Diabetic Mice

Depression is a frequent and serious comorbidity associated with diabetes which adversely affects prognosis and quality of life. Glucagon-like peptide-1 receptor (GLP-1R) agonists, widely used in the treatment of diabetes, are reported to exert neuroprotective effects in the central nervous system. Thus, we aim to evaluate whether GLP-1R agonist exendin-4 (EX-4) could alleviate depression-like behaviors in diabetic mice and to explore its underlying mechanism. The antidepressant effects of EX-4 were evaluated using behavioral tests in db/db mice. The effects of EX-4 on microglial pyroptosis and neuroinflammation were assessed in N9 microglial cells. EX-4 administration alleviated depression-like behaviors in diabetic db/db mice. GLP-1R activation by EX-4 significantly suppressed microglial pyroptosis and neuroinflammation by downregulation of gasdermin D (GSDMD) and interleukin (IL)-1β in diabetic mice and lipopolysaccharide (LPS)-primed N9 microglia. Mechanistically, GLP-1R activation improved mitochondrial function and promoted mitophagy by decreasing the accumulation of mitochondrial reactive oxygen species (mtROS) and intracellular ROS production. EX-4 exhibits antidepressant effects in depression associated with diabetes in diabetic mice, which may be mediated by inhibiting microglial pyroptisis via promoting mitophagy. It is supposed that GLP-1R agonists may be a promising therapy in depression associated with diabetes.

Will GLP-1 Analogues and SGLT-2 Inhibitors Become New Game Changers for Diabetic Retinopathy?

Diabetic retinopathy (DR) is the most frequent microvascular complication of diabetes mellitus (DM), estimated to affect approximately one-third of the diabetic population, and the most common cause of preventable vision loss. The available treatment options focus on the late stages of this complication, while in the early stages there is no dedicated treatment besides optimizing blood pressure, lipid and glycemic control; DR is still lacking effective preventive methods. glucagon-like peptide 1 receptor agonists (GLP-1 Ras) and sodium-glucose cotransporter 2 (SGLT-2) inhibitors have a proven effect in reducing risk factors of DR and numerous experimental and animal studies have strongly established its retinoprotective potential. Both drug groups have the evident potential to become a new therapeutic option for the prevention and treatment of diabetic retinopathy and there is an urgent need for further comprehensive clinical trials to verify whether these findings are translatable to humans.

Exenatide once weekly for alcohol use disorder investigated in a randomized, placebo-controlled clinical trial

BackgroundAlcohol use disorder (AUD) is a chronic, relapsing brain disorder that accounts for 5% of deaths annually, and there is an urgent need to develop new targets for therapeutic intervention. The glucagon-like peptide-1 (GLP-1) receptor agonist exenatide reduces alcohol consumption in rodents and nonhuman primates, but its efficacy in patients with AUD is unknown.MethodsIn a randomized, double-blinded, placebo-controlled clinical trial, treatment-seeking AUD patients were assigned to receive exenatide (2 mg subcutaneously) or placebo once weekly for 26 weeks, in addition to standard cognitive-behavioral therapy. The primary outcome was reduction in number of heavy drinking days. A subgroup also completed functional MRI (fMRI) and single-photon emission CT (SPECT) brain scans.ResultsA total of 127 patients were enrolled. Our data revealed that although exenatide did not significantly reduce the number of heavy drinking days compared with placebo, it significantly attenuated fMRI alcohol cue reactivity in the ventral striatum and septal area, which are crucial brain areas for drug reward and addiction. In addition, dopamine transporter availability was lower in the exenatide group compared with the placebo group. Exploratory analyses revealed that exenatide significantly reduced heavy drinking days and total alcohol intake in a subgroup of obese patients (BMI > 30 kg/m2). Adverse events were mainly gastrointestinal.ConclusionThis randomized controlled trial on the effects of a GLP-1 receptor agonist in AUD patients provides new important knowledge on the effects of GLP-1 receptor agonists as a novel treatment target in addiction.Trial registrationEudraCT: 2016-003343-11. ClinicalTrials.gov (NCT03232112).FundingNovavi Foundation; Research Foundation, Mental Health Services, Capital Region of Denmark; Research Foundation, Capital Region of Denmark; Ivan Nielsen Foundation; A.P. Moeller Foundation; Augustinus Foundation; Woerzner Foundation; Grosserer L.F. Foghts Foundation; Hartmann Foundation; Aase and Ejnar Danielsen Foundation; P.A. Messerschmidt and Wife Foundation; and Lundbeck Foundation.

GLP-1 agonists: superior for mind and body in antipsychotic-treated patients?

Antipsychotics (APDs) represent a core treatment for severe mental disorders (SMEs). Providing symptomatic relief, APDs do not exert therapeutic effects on another clinically significant domain of serious mental disorders, cognitive impairment. Moreover, adverse metabolic effects (diabetes, weight gain, dyslipidemia, and increased cardiovascular risk) are common during treatment with APDs. Among pharmacological candidates reversing APD-induced metabolic adverse effects, glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs), approved for both diabetes and recently for obesity treatment, stand out due to their favorable effects on peripheral metabolic parameters. Interestingly, GLP-1 RAs are also proposed to have pro-cognitive effects. Particularly in terms of dual therapeutic mechanisms potentially improving both central nervous system (CNS) deficits and metabolic burden, GLP-1 RAs open a new perspective and assume a clinically advantageous position.

Differential association between the GLP1R gene variants and brain functional connectivity according to the severity of alcohol use

Growing evidence suggests that the glucagon-like peptide-1 (GLP-1) system is involved in mechanisms underlying alcohol seeking and consumption. Accordingly, the GLP-1 receptor (GLP-1R) has begun to be studied as a potential pharmacotherapeutic target for alcohol use disorder (AUD). The aim of this study was to investigate the association between genetic variation at the GLP-1R and brain functional connectivity, according to the severity of alcohol use. Participants were 181 individuals categorized as high-risk (n = 96) and low-risk (n = 85) alcohol use, according to their AUD identification test (AUDIT) score. Two uncommon single nucleotide polymorphisms (SNPs), rs6923761 and rs1042044, were selected a priori for this study because they encode amino-acid substitutions with putative functional consequences on GLP-1R activity. Genotype groups were based on the presence of the variant allele for each of the two GLP-1R SNPs of interest [rs6923761: AA + AG (n = 65), GG (n = 116); rs1042044: AA + AC (n = 114), CC (n = 67)]. Resting-state functional MRI data were acquired for 10 min and independent component (IC) analysis was conducted. Multivariate analyses of covariance (MANCOVA) examined the interaction between GLP-1R genotype group and AUDIT group on within- and between-network connectivity. For rs6923761, three ICs showed significant genotype × AUDIT interaction effects on within-network connectivity: two were mapped onto the anterior salience network and one was mapped onto the visuospatial network. For rs1042044, four ICs showed significant interaction effects on within-network connectivity: three were mapped onto the dorsal default mode network and one was mapped onto the basal ganglia network. For both SNPs, post-hoc analyses showed that in the group carrying the variant allele, high versus low AUDIT was associated with stronger within-network connectivity. No significant effects on between-network connectivity were found. In conclusion, genetic variation at the GLP-1R was differentially associated with brain functional connectivity in individuals with low versus high severity of alcohol use. Significant findings in the salience and default mode networks are particularly relevant, given their role in the neurobiology of AUD and addictive behaviors.

Mechanisms of antidiabetic drugs and cholesterol efflux: A clinical perspective

Reverse cholesterol transport (RCT) is a physiological process that reduces excess cholesterol in the body. Cholesterol efflux (CE), an important step in RCT, is mainly mediated by ATP-binding cassette transporters A1 and G1 and has a significant role in atheroprotection. Moreover, impairments in CE can lead to the development of diabetes and fatty liver disease. In this review, we summarize the possible effects of hypoglycemic agents on CE and how this might influence atherosclerosis and dyslipidemia-related pathologies. Newer antidiabetic agents could have significant potential for targeting CE and preventing or alleviating atherosclerosis, obesity, and liver steatosis, and simultaneously improving insulin secretion. However, more research is warranted to interpret the clinical relevance of these data.

Type 2 diabetes mellitus-associated cognitive dysfunction: Advances in potential mechanisms and therapies

Type 2 diabetes (T2D) and its target organ injuries cause distressing impacts on personal health and put an enormous burden on the healthcare system, and increasing attention has been paid to T2D-associated cognitive dysfunction (TDACD). TDACD is characterized by cognitive dysfunction, delayed executive ability, and impeded information-processing speed. Brain imaging data suggest that extensive brain regions are affected in patients with T2D. Based on current findings, a wide spectrum of non-specific neurodegenerative mechanisms that partially overlap with the mechanisms of neurodegenerative diseases is hypothesized to be associated with TDACD. However, it remains unclear whether TDACD is a consequence of T2D or a complication that co-occurs with T2D. Theoretically, anti-diabetes methods are promising neuromodulatory approaches to reduce brain injury in patients with T2D. In this review, we summarize potential mechanisms underlying TDACD and promising neurotropic effects of anti-diabetes methods and some neuroprotective natural compounds. Constructing screening or diagnostic tools and developing targeted treatment and preventive strategies would be expected to reduce the burden of TDACD.

The Role of Glp-1 Receptor Agonists in Insulin Resistance with Concomitant Obesity Treatment in Polycystic Ovary Syndrome

Insulin resistance is documented in clamp studies in 75% of women with polycystic ovary syndrome (PCOS). Although it is not included in the diagnostic criteria of PCOS, there is a crucial role of this metabolic impairment, which along with hormonal abnormalities, increase each other in a vicious circle of PCOS pathogenesis. Insulin resistance in this group of patients results from defects at the molecular level, including impaired insulin receptor-related signaling pathways enhanced by obesity and its features: Excess visceral fat, chronic inflammation, and reactive oxygen species. While lifestyle intervention has a first-line role in the prevention and management of excess weight in PCOS, the role of anti-obesity pharmacological agents in achieving and maintaining weight loss is being increasingly recognized. Glucagon-like peptide-1 receptor agonists (GLP1-RAs) not only act by reducing body weight but also can affect the mechanisms involved in insulin resistance, like an increasing expression of glucose transporters in insulin-dependent tissues, decreasing inflammation, reducing oxidative stress, and modulating lipid metabolism. They also tend to improve fertility either by increasing LH surge in hypothalamus-pituitary inhibition due to estrogen excess connected with obesity or decreasing too high LH levels accompanying hyperinsulinemia. GLP1-RAs seem promising for effective treatment of obese PCOS patients, acting on one of the primary causes of PCOS at the molecular level.

The effect of Glucagon-like peptide-1 receptor agonists on serum uric acid concentration: A systematic review and meta-analysis

AIMS

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a class of medications mainly used for the treatment of type 2 diabetes. They improve glucose tolerance, increase insulin secretion, and induce weight loss. There is controversy about the effect of GLP-1RAs on serum uric acid (SUA) concentration. Our systematic review aims to objectively answer whether GLP-1RAs affect SUA levels.

METHODS

We performed a systematic search on PubMed, Web of Science, Embase, Scopus, and Google Scholar datasets up to 27August,2021 with a language restriction of English only. Randomized controlled trials, observational studies, uncontrolled trials, and conference abstracts were included. Studies with insufficient data, irrelevant types of study, and follow-up duration of less than a month were excluded from the review. After critical appraisal by the Joanna Briggs Institute checklists, articles underwent data extraction using a pre-specified Microsoft Excel sheet.

RESULTS

Of 1004 identified studies, 17 were eligible for inclusion in this systematic review. Pre- to post-administration analysis of GLP-1RA effects on SUA demonstrated that GLP-1RAs could significantly reduce SUA concentration (difference in means=-0.341;SE=0.063;P-value<0.001). However, when compared to placebo, GLP-1 RAs did not perform any better in lowering SUA concentration (difference in means=-0.455;SE=0.259;P-value=0.079). Surprisingly, the active controls, that included insulin, metformin, sodium-glucose co-transporter 2 (SGLT-2) inhibitors, and dipeptidyl-peptidase 4 (DPP-4) inhibitors, did outperform GLP-1RAs in reducing SUA concentration (difference in means=0.250;SE=0.038;P-value<0.001).

CONCLUSIONS

Administration of GLP-1RAs can result in a significant reduction in SUA concentration. However, this reduction is less than that seen with the use of insulin, metformin, and SGLT-2 inhibitors.

Liraglutide Reduces Vascular Damage, Neuronal Loss, and Cognitive Impairment in a Mixed Murine Model of Alzheimer's Disease and Type 2 Diabetes

Alzheimer's disease is the most common form of dementia, and epidemiological studies support that type 2 diabetes (T2D) is a major contributor. The relationship between both diseases and the fact that Alzheimer's disease (AD) does not have a successful treatment support the study on antidiabetic drugs limiting or slowing down brain complications in AD. Among these, liraglutide (LRGT), a glucagon-like peptide-1 agonist, is currently being tested in patients with AD in the Evaluating Liraglutide in Alzheimer's Disease (ELAD) clinical trial. However, the effects of LRGT on brain pathology when AD and T2D coexist have not been assessed. We have administered LRGT (500 μg/kg/day) to a mixed murine model of AD and T2D (APP/PS1xdb/db mice) for 20 weeks. We have evaluated metabolic parameters as well as the effects of LRGT on learning and memory. Postmortem analysis included assessment of brain amyloid-β and tau pathologies, microglia activation, spontaneous bleeding and neuronal loss, as well as insulin and insulin-like growth factor 1 receptors. LRGT treatment reduced glucose levels in diabetic mice (db/db and APP/PS1xdb/db) after 4 weeks of treatment. LRGT also helped to maintain insulin levels after 8 weeks of treatment. While we did not detect any effects on cortical insulin or insulin-like growth factor 1 receptor m-RNA levels, LRGT significantly reduced brain atrophy in the db/db and APP/PS1xdb/db mice. LRGT treatment also rescued neuron density in the APP/PS1xdb/db mice in the proximity (p = 0.008) far from amyloid plaques (p < 0.001). LRGT reduced amyloid plaque burden in the APP/PS1 animals (p < 0.001), as well as Aβ aggregates levels (p = 0.046), and tau hyperphosphorylation (p = 0.009) in the APP/PS1xdb/db mice. Spontaneous bleeding was also ameliorated in the APP/PS1xdb/db animals (p = 0.012), and microglia burden was reduced in the proximity of amyloid plaques in the APP/PS1 and APP/PS1xdb/db mice (p < 0.001), while microglia was reduced in areas far from amyloid plaques in the db/db and APP/PS1xdb/db mice (p < 0.001). This overall improvement helped to rescue cognitive impairment in AD-T2D mice in the new object discrimination test (p < 0.001) and Morris water maze (p < 0.001). Altogether, our data support the role of LRGT in reduction of associated brain complications when T2D and AD occur simultaneously, as regularly observed in the clinical arena.

The mechanism and efficacy of GLP-1 receptor agonists in the treatment of Alzheimer's disease

Since type 2 diabetes mellitus (T2DM) is a risk factor for Alzheimer's disease (AD) and both have the same pathogenesis (e.g., insulin resistance), drugs used to treat T2DM have been gradually found to reduce the progression of AD in AD models. Of these drugs, glucagon-like peptide 1 receptor (GLP-1R) agonists are more effective and have fewer side effects. GLP-1R agonists have reducing neuroinflammation and oxidative stress, neurotrophic effects, decreasing Aβ deposition and tau hyperphosphorylation in AD models, which may be a potential drug for the treatment of AD. However, this needs to be verified by further clinical trials. This study aims to summarize the current information on the mechanisms and effects of GLP-1R agonists in AD.

Impact of glucagon-like peptide 1 analogs on cognitive function among patients with type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Diabetes is an independent risk factor for cognitive impairment. However, little is known about the neuroprotective effects of glucagon-like peptide 1 (GLP-1) analogs on type 2 diabetes mellitus (T2DM). Herein, we assessed the impact of GLP-1 analogs on the general cognitive functioning among patients with T2DM.

METHODS

Relevant studies were retrieved from PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases from their inception till June 30, 2022, without any language restrictions. For continuous variables, the mean and standard deviation (SD) were extracted. Considering the heterogeneity in general cognitive functioning assessments among the pooled studies, the standardized mean differences (SMDs) with corresponding 95% confidence intervals (CIs), were calculated.

RESULTS

Five studies including 7,732 individuals with T2DM were selected for the meta-analysis. The use of GLP-1 analogs exerted no significant effects on the general cognitive functioning in self-controlled studies (SMD 0.33, 95% CI -0.03 to 0.69). Subgroup analyses among the self-controlled studies based on age and history of cardio-cerebrovascular disease showed that GLP-1 analogs significantly improved the general cognitive functioning in T2DM patients younger than 65 years (SMD 0.69, 95% CI 0.31 to 1.08) or those without cardio-cerebrovascular diseases (SMD 0.69, 95% CI 0.31 to 1.08). Similarly, differences in the general cognitive functioning for GLP-1 analogs between treated and non-treated patients with T2DM were significant in subgroups with patients younger than 65 years (SMD 1.04, 95% CI 0.61 to 1.47) or those with no history of cardio-cerebrovascular diseases (SMD 1.04, 95% CI 0.61 to 1.47).

CONCLUSION

Limited evidence suggests that the use of GLP-1 analogs exerts no significant effects on general cognitive functioning but may be beneficial for patients with T2DM younger than 65 years or those without a history of cardio-cerebrovascular diseases. Further prospective clinical studies with large sample sizes are needed to validate these findings.

SYSTEMATIC REVIEW REGISTRATION

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