Extended-release metformin improves cognitive impairment in frail older women with hypertension and diabetes: preliminary results from the LEOPARDESS Study

Risk Factors, Pathological Changes, and Potential Treatment of Diabetes-Associated Cognitive Dysfunction

BACKGROUND

Diabetes is a prevalent public health issue worldwide, and the cognitive dysfunction and subsequent dementia caused by it seriously affect the quality of life of patients.

METHODS

Recent studies were reviewed to provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for diabetes-related cognitive dysfunction (DACD).

RESULTS

Several risk factors contribute to DACD, including hyperglycemia, hypoglycemia, blood sugar fluctuations, hyperinsulinemia, aging, and others. Among them, modifiable risk factors for DACD include blood glucose control, physical activity, diet, smoking, and hypertension management, while non-modifiable risk factors include age, genetic predisposition, sex, and duration of diabetes. At the present, the pathogenesis of DACD mainly includes insulin resistance, neuroinflammation, vascular disorders, oxidative stress, and neurotransmitter disorders.

CONCLUSIONS

In this review, we provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for DACD, providing information from multiple perspectives for its prevention and management.

Metformin Improves Spatial Memory and Reduces Seizure Severity in a Rat Model of Epilepsy and Alzheimer's Disease comorbidity via PI3K/Akt Signaling Pathway

Emerging evidence suggests a bidirectional relationship between Alzheimer's disease (AD) and epilepsy. In our previous studies, we identified a partial AD-like phenotype associated with central insulin resistance in the Wistar audiogenic rat (WAR), a genetic model of epilepsy. We also found that intracerebroventricular administration of streptozotocin, a compound used to model diabetes and AD, exacerbates seizure susceptibility. Given the role of insulin signaling in both AD and epilepsy, we hypothesized that metformin (MET), an anti-diabetic drug known for enhancing insulin sensitivity, could be a potential therapeutic agent for both conditions. Our objective was to investigate MET's effects on brain insulin signaling, seizure activity, and AD-like pathology in WARs. Adult male WARs received oral MET (250 mg/kg) for 21 days. Audiogenic seizures were assessed using the Categorized Severity Index and Racine's scale. Spatial memory was tested with the Morris water maze (MWM), followed by Western blot analysis of hippocampal proteins. MET significantly reduced seizure severity and improved MWM performance. Although MET did not affect insulin receptor levels or activation, it increased phosphoinositide 3-kinase (PI3K), activated Akt, and increased glycogen synthase kinase-3α/β (GSK-3α/β) levels. MET also decreased amyloid β precursor protein (AβPP) levels but did not affect Tau phosphorylation. These results suggest that chronic MET treatment alleviates behaviors related to both AD and epilepsy in WARs and modulates insulin signaling independently of insulin receptor activation. Our findings highlight MET's potential as a therapeutic agent for managing comorbid AD and epilepsy, warranting further investigation into its mechanisms of action.

Exploring the protective effect of metformin against sarcopenia: insights from cohort studies and genetics

BACKGROUND

The impact of metformin on sarcopenia remains uncertain. This study aimed to investigate whether metformin influences sarcopenia risk and evaluate the effects of potential drug targets on sarcopenia traits.

METHODS

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) (n = 3549) to assess the association between metformin use and sarcopenia risk in elderly patients with type 2 diabetes. Mendelian randomization (MR) analysis using genome-wide association studies (GWAS) from UK Biobank (n = 1,366,167) and FinnGen (n = 218,007), with expression quantitative trait loci (eQTL) as instrumental variables, examined the causal effect of metformin-related targets on sarcopenia traits, while molecular docking explored the interaction between metformin and its drug targets.

RESULTS

Metformin use was associated with increased grip strength (OR = 2.46; 95% CI 1.49-2.38) and skeletal muscle mass (OR = 1.24; 95% CI 0.20-2.28), as well as reduced mortality (HR = 0.62; 95% CI 0.54-0.71). MR analysis suggested a possible link between GDF15 gene expression and sarcopenia traits, with no evidence of genetic confounding. Molecular docking indicated stable binding between metformin and GDF15.

CONCLUSION

This study suggests that metformin may lower sarcopenia risk, particularly in elderly patients with type 2 diabetes, with GDF15 identified as a promising target for sarcopenia treatment.

Frailty incidence by diabetes treatment regimens in older adults with diabetes mellitus in the ASPirin in Reducing Events in the Elderly Study

Diabetes mellitus is a major risk factor for frailty in older adults, and studies suggest that frailty risk may differ by diabetes treatment regimen. To investigate the association between diabetes medication use and frailty, we conducted an observational cohort analysis of older adults with diabetes enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) study. Diabetes at baseline (N = 2045) was defined as self-reported diabetes, fasting blood glucose levels > 125 mg/dL, or use of diabetes medication. Diabetes medication exposure at baseline was categorized as use of metformin only (monotherapy) (N = 545), metformin combined with other diabetes medications (N = 420), other diabetes medications only (N = 200), or no diabetes medications (N = 880). Frailty was defined using a modified Fried frailty phenotype (presence of ≥ 3 of 5 criteria) and a deficit accumulation frailty index (FI, score > 0.21/1.00). Mixed effects ordinal logistic regression models revealed the odds of frailty at baseline were highest for the other diabetes medications only group, but this difference remained consistent over follow-up. After adjustment for covariates, including baseline pre-frailty, no differences in the rates of Fried or FI frailty were observed among the diabetes medication exposure groups. These findings suggest that diabetes medication exposure in older adults with diabetes does not directly impact frailty risk.

Interleukin-5: an indicator of mild cognitive impairment in patients with type 2 diabetes mellitus - a comprehensive investigation ranging from bioinformatics analysis to clinical research

PURPOSE

Neuroinflammation constitutes an underlying mechanism for cognitive impairment. Here, we endeavor to scrutinize the potential contribution of interleukin-5 (IL-5) towards mild cognitive impairment (MCI), and to assess its diagnostic value for MCI in patients with type 2 diabetes mellitus (T2DM).

METHODS

RNA-seq was used to explore the potential neuroinflammation factors in the hippocampus of diabetic mice with cognitive decline. Additionally, the promising risk factor was verified in animals. Finally, the association between IL-5 levels and cognitive function and its diagnostic value for MCI were assessed.

RESULTS

In animals, up-regulated IL-5 mRNA and protein levels were detected by RNA-seq and (or) verified experiments in the hippocampus of diabetic db/db mice with cognitive decline, compared to those of db/m mice without diabetes. In human, compared to diabetic patients without MCI, those with MCI demonstrate elevated levels of IL-5. It is natively associated with Montreal Cognitive Assessment (MoCA) scores, reflecting global cognitive function, and positively correlated with Trail Making Test A (TMTA) scores, reflecting information processing speed. Furthermore, an elevated level of IL-5 is identified as a risk factor for MCI, and a factor that influences TMTA scores. Finally, it is recommended that the cut-off value for IL-5 in the diagnosis of MCI is 22.98 pg/mL, with a sensitivity of 68.6% and specificity of 72.9%.

CONCLUSIONS

IL-5 is considered a risk factor for MCI in T2DM patients and is associated with their performance in information processing speed. Moreover, an elevated level of IL-5 is a plausible biomarker for MCI in T2DM patients.

Development and Validation of a Predictive Model for Early Identification of Cognitive Impairment Risk in Community-Based Hypertensive Patients

Objective: To investigate the risk factors for the development of mild cognitive dysfunction in hypertensive patients in the community and to develop a risk prediction model. Method: The data used in this study were obtained from two sources: the China Health and Retirement Longitudinal Study (CHARLS) and the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 1121 participants from CHARLS were randomly allocated into a training set and a validation set, following a 70:30 ratio. Meanwhile, an additional 4016 participants from CLHLS were employed for external validation of the model. The patients in this study were divided into two groups: those with mild cognitive impairment and those without. General information, employment status, pension, health insurance, and presence of depressive symptoms were compared between the two groups. LASSO regression analysis was employed to identify the most predictive variables for the model, utilizing 14-fold cross-validation. The risk prediction model for cognitive impairment in hypertensive populations was developed using generalized linear models. The model's discriminatory power was evaluated through the area under the receiver operating characteristic (ROC) curve and calibration curves. Results: In the modeling group, eight variables such as gender, age, residence, education, alcohol use, depression, employment status, and health insurance were ultimately selected from an initial pool of 21 potential predictors to construct the risk prediction model. The area under the curve (AUC) values for the training, internal, and external validation sets were 0.777, 0.785, and 0.782, respectively. All exceeded the threshold of 0.7, suggesting that the model effectively predicts the incidence of mild cognitive dysfunction in community-based hypertensive patients. A risk prediction model was developed using a generalized linear model in conjunction with Lasso regression. The model's performance was evaluated using the area under the receiver operating characteristic (ROC) curve. Hosmer-Lemeshow test values yielded p = .346 and p = .626, both of which exceeded the 0.05 threshold. Calibration curves demonstrated a significant agreement between the nomogram model and observed outcomes, serving as an effective tool for evaluating the model's predictive performance. Discussion: The predictive model developed in this study serves as a promising and efficient tool for evaluating cognitive impairment in hypertensive patients, aiding community healthcare workers in identifying at-risk populations.

Metformin associates with higher myocardial perfusion reserve and survival in type 2 diabetes mellitus patients

Metformin is an antihyperglycemic used to treat type 2 diabetes mellitus (T2DM). Patients with T2DM are at increased risk of cardiovascular disease. We explored the association between metformin use and cardiovascular magnetic resonance (CMR) derived stress myocardial blood flow (MBF), myocardial perfusion reserve (MPR) and major adverse cardiovascular events (MACE; all cause death, MI, stroke, heart failure hospitalisation and coronary revascularisation) in patients with T2DM. Multi-centre study of patients with T2DM, and healthy controls, underwent quantitative myocardial perfusion CMR using an artificial intelligence supported process. Multivariable regression analysis, and cox proportional hazard models of propensity score weighted patients quantified associations between metformin use, MBF, MPR, all cause death and MACE. Analysis included 572 patients with T2DM (68% prescribed metformin) with median follow-up 851 days (IQR 935 - 765). Metformin use was associated with an increase of MPR of 0.12 [0.08-0.40], p = 0.004. There were 82 MACE events (14.3%) including 25 (4.4%) deaths of which 16 were in those not prescribed metformin (8.7%), compared to 9 in patients prescribed metformin (2.3%): adjusted hazard ratio 0.24 (95% CI 0.08-0.70, p = 0.009). MACE events were similar between groups. This multicentre, inverse probability weighting propensity score analysis study showed that in patients with T2DM, metformin use is associated with higher MPR and improved all cause survival.

Metformin improves cognitive dysfunction through SIRT1/NLRP3 pathway-mediated neuroinflammation in db/db mice

Diabetes mellitus (DM), an important public health problem, aggravates the global economic burden. Diabetic encephalopathy (DE) is a serious complication of DM in the central nervous system. Metformin has been proven to improve DE. However, the mechanism is still unclear. In this study, the db/db mice, a common model used for DE, were employed to explore and study the neuroprotective effect of metformin and related mechanisms. Behavioral tests indicated that metformin (100 or 200 mg/kg/day) could significantly improve the learning and memory abilities of db/db mice. The outcomes from the oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) demonstrate that metformin effectively modulates glucose and insulin signaling pathways in db/db mice. The results of body weight and blood lipid panel (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol) show that metformin promotes the level of lipid metabolism in db/db mice. Furthermore, data from oxidative stress assays, which measured levels of malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase, suggest that metformin suppresses oxidative stress-induced brain damage in db/db mice. In addition, western blot, Nissl staining, and immunofluorescence results showed that metformin increased the expressions of nerve growth factor and postsynaptic density 95 and repaired neuronal structural damage. For the mechanism study, metformin activated SIRT1 and inhibited the expression of NLRP3 inflammasome (NLRP3, ASC, caspase-1, IL-1β, and IL-18) and inflammatory cytokines (TNFα and IL-6). In conclusion, metformin could ameliorate cognitive dysfunction through the SIRT1/NLRP3 pathway, which might be a promising mechanism for DE treatment.

Prediabetes Increases the Risk of Frailty in Prefrail Older Adults With Hypertension: Beneficial Effects of Metformin

BACKGROUND

Prediabetes has garnered increasing attention due to its association with cardiovascular conditions, especially hypertension, which heightens the risk of prefrailty and frailty among older individuals.

METHODS

We screened elders with prefrail hypertension from March 2021 to January 2023. We assessed the correlation linking cognitive dysfunction (Montreal Cognitive Assessment score), insulin resistance (triglyceride-to-glucose index), and physical impairment (5-meter gait speed). Then, we measured the risk of developing frailty after a 1-year follow-up period, adjusting the outcome using multivariable Cox regression analysis. We also investigated the impact of administering 500 mg of metformin once daily to a subset of frail subjects for an additional 6 months.

RESULTS

We assessed the relationship between the triglyceride-to-glucose index and the Montreal Cognitive Assessment score, observing a significant correlation (r, 0.880; P<0.0001). Similarly, we analyzed the association between the triglyceride-to-glucose index and 5-meter gait speed, uncovering a significant link between insulin resistance and physical impairment (r, 0.809; P<0.0001). Prediabetes was found to significantly (P<0.0001) elevate the risk of frailty development compared with individuals without prediabetes by the end of the 1-year follow-up, a finding confirmed via multivariable analysis with Cox regression. Furthermore, among the subgroup of subjects who developed frailty, those who received metformin exhibited a significant decrease in frailty levels (P<0.0001).

CONCLUSIONS

Insulin resistance and prediabetes play substantial roles in the development of cognitive and physical impairments, highlighting their importance in managing hypertension, even before the onset of frank diabetes. Metformin, a well-established drug for the treatment of diabetes, has shown favorable effects in mitigating frailty.

Frailty and Parkinson's disease: the role of diabetes mellitus

Parkinson's disease (PD) is a chronic neurodegenerative disease associated with a progressive loss of dopaminergic neurons, clinically characterized by motor and non-motor signs. Frailty is a clinical condition of increased vulnerability and negative health outcomes due to the loss of multiple physiological reserves. Chronic hyperglycemia and insulin resistance, which characterize diabetes mellitus (DM), have been reported to alter dopaminergic activity, increase the risk of PD, and influence the development of frailty. Even though diabetes may facilitate the development of frailty in patients with PD, this relationship is not established and a revision of the current knowledge is necessary. Furthermore, the synergy between DM, PD, and frailty may drive clinical complexity, worse outcomes, and under-representation of these populations in the research. In this review, we aimed to discuss the role of diabetes in the development of frailty among patients with PD. We summarized the clinical characteristics and outcomes of patients with concomitant DM, PD, and frailty. Finally, interventions to prevent frailty in this population are discussed.

Metformin mitigates dementia risk among individuals with type 2 diabetes

This mini-narrative review explores the relationship between diabetes and dementia, focusing on the potential mitigating role of metformin in reducing cognitive decline among individuals with type 2 diabetes. The interplay of factors such as glycemic control, diabetic complications, and lifestyle influences characterises diabetes-related dementia. This review emphasises the significance of comprehensive diabetes management in addressing the heightened risk of dementia in this population. Methodologically, the review synthesises evidence from 23 studies retrieved through searches on PubMed, Embase, Google Scholar, and Scopus. Current evidence suggests a predominantly positive association between metformin use and a reduced risk of dementia in individuals with diabetes. However, the review shows the complex nature of these outcomes, revealing variations in results in some studies. These discrepancies show the importance of exploring dose-response relationships, long-term effects, and demographic diversity to unravel the complexities of metformin's impact on cognitive health. Limitations in the existing body of research, including methodological disparities and confounding variables, necessitate refined approaches in future studies. Large-scale prospective longitudinal studies and randomised controlled trials focusing specifically on cognitive effects are recommended. Propensity score matching and exploration of molecular mechanisms can enhance the validity of findings in clinical practice. From a clinical perspective, metformin can serve as a potential adjunctive therapy for individuals with diabetes at risk of cognitive decline.

Frail hypertensive older adults with prediabetes and chronic kidney disease: insights on organ damage and cognitive performance - preliminary results from the CARYATID study

BACKGROUND

Hypertension and chronic kidney disease (CKD) pose significant public health challenges, sharing intertwined pathophysiological mechanisms. Prediabetes is recognized as a precursor to diabetes and is often accompanied by cardiovascular comorbidities such as hypertension, elevating the risk of pre-frailty and frailty. Albuminuria is a hallmark of organ damage in hypertension amplifying the risk of pre-frailty, frailty, and cognitive decline in older adults. We explored the association between albuminuria and cognitive impairment in frail older adults with prediabetes and CKD, assessing cognitive levels based on estimated glomerular filtration rate (eGFR).

METHODS

We conducted a study involving consecutive frail older patients with hypertension recruited from March 2021 to March 2023 at the ASL (local health unit of the Italian Ministry of Health) of Avellino, Italy, followed up after three months. Inclusion criteria comprised age over 65 years, prior diagnosis of hypertension without secondary causes, prediabetes, frailty status, Montreal Cognitive Assessment (MoCA) score < 26, and CKD with eGFR > 15 ml/min.

RESULTS

237 patients completed the study. We examined the association between albuminuria and MoCA Score, revealing a significant inverse correlation (r: 0.8846; p < 0.0001). Subsequently, we compared MoCA Score based on eGFR, observing a significant difference (p < 0.0001). These findings were further supported by a multivariable regression analysis, with albuminuria as the dependent variable.

CONCLUSIONS

Our study represents the pioneering effort to establish a significant correlation between albuminuria and eGFR with cognitive function in frail hypertensive older adults afflicted with prediabetes and CKD.

Evaluation of the prevalence of cardiometabolic disorders (diabetes, hypertension, and hyperlipidemia) diagnosed, undiagnosed, treated, and treatment goal in the elderly: Bushehr Elderly Health Program (BEH)

As the population ages, the global burden of cardiometabolic disorders will increase. This study aimed to investigate the prevalence of cardiometabolic disorders (diabetes, hypertension, and hyperlipidemia) in elderly and to evaluate the effects of various variables including age, sex, education, marital status, smoking, income, physical activity, dementia and depressed mood on untreated cardiometabolic disorders. This was a cross sectional study conducted in Bushehr Elderly Health Program. A total 2381 participants were included. Medical data were collected by trained interviewers. The mean age of the study participants was 69.34 years. Proportions of diabetes, hypertension, hyperlipidemia and hypercholesterolemia were 43.25%, 75.71%, 64.74% and 35.31% respectively. Untreated diabetes prevalence was higher for males (OR = 1.60, 95%CI = 1.20-2.15), older adults (OR = 1.02, 95%CI = 1.00-1.05), and pre-frail status (OR = 0.69, 95%CI = 0.52-0.92). Males (OR = 2.16, 95%CI = 1.64-2.84) and current smokers (OR = 1.42, 95%CI = 1.05-1.93), in contrast to married participants (OR = 0.25, 95%CI = 0.08-0.78), people with higher education levels (OR = 0.51, 95%CI = 0.29-0.89) and dementia (OR = 0.78, 95%CI = 0.61-1.00) were more likely to have untreated HTN. Untreated dyslipidemia is more common in smokers (OR = 1.78, 95%CI = 1.19-2.66) and males (OR = 1.66, 95%CI = 1.21-2.27), while untreated hypercholesteremia is more common in males (OR = 3.20, 95%CI = 1.53-6.69) and is reported lower in people with dementia (OR = 0.53, 95%CI = 0.28-1.01).

Pathogens in Crohn's Disease: The Role of Adherent Invasive Escherichia coli

In Crohn's disease (CD), gut dysbiosis is marked by the prevalence of pathogenic bacterial species. Although several microbes have been reported as risk factors or causative agents of CD, it is not yet clear which is the real trigger of the disease. Thirty years ago, a new pathovar of Escherichia coli strain was isolated in the ileal mucosa of CD patients. This strain, called adherent invasive E. coli (AIEC), for its ability to invade the intestinal mucosa, could represent the causative agent of the disease. Several authors studied the mechanisms by which the AIEC penetrate and replicate within macrophages, and release inflammatory cytokines sustaining inflammation. In this review we will discuss about the role of AIEC in the pathogenesis of CD, the virulence factors mediating adhesion and invasion of AIEC in mucosal tissue, the environmental conditions improving AIEC survival and replication within macrophages. Finally, we will also give an overview of the new strategies developed to limit AIEC overgrowth.

Effect of blood pressure on mortality in patients with cognitive impairment: a prospective cohort study

Background

Cognitive impairment is a prevalent condition that substantially elevates mortality rates among the elderly. The impact of hypertension on mortality in older adults with cognitive impairment is a subject of contention. This study aims to examine the influence of hypertension on both all-cause and CVD-specific mortality in elderly individuals experiencing cognitive impairment within a prospective cohort.

Methods

This study encompassed 2,925 participants (weighted 53,086,905) aged 60 years or older from National Health and Nutrition Examination Survey (NHANES) spanning 2011-2014. Incidence of all-cause and CVD-specific mortality was ascertained through linkage with National Death Index records until 31 December 2019. Survival was performed employing the Kaplan-Meier method. Hazard ratios (HRs) were calculated via Cox proportional hazards regression models.

Results

Over the follow-up period of up to 9.17 years [with a median (IQR) time to death of 6.58 years], equivalent to 18,731.56 (weighted 3.46 × 108) person-years, there were a total of 576 recorded deaths. Participants with CI exhibited a 1.96-fold higher risk of all-cause mortality (95% CI: 1.55-2.49; p < 0.01) and a 2.8-fold higher risk of CVD-specific mortality (95% CI: 1.83-4.29; p < 0.01) in comparison to participants without CI. Among participants with CI, concurrent hypertension comorbidity was linked to a 2.73-fold elevated risk of all-cause mortality (95% CI: 1.78-4.17; p < 0.01) and a 5.3-fold elevated risk of CVD-specific mortality (95% CI: 2.54-11.04; p < 0.01). Further stratified analyses revealed that the combined effects of hypertension and CI on all-cause and CVD-specific mortality were more pronounced in participants aged 60-69 years compared to those aged 70-80 years (p for interaction <0.01). The primary findings exhibited resilience across a series of sensitivity analyses.

Conclusions

Participants with CI exhibited a markedly elevated risk of all-cause and CVD-specific mortality when coexisting with hypertension. Appropriate management of hypertension in patients with CI may be helpful in reducing the excess risk of death.

The outcome of frailty in older people with diabetes as a function of glycaemic control and hypoglycaemic therapy: a review

INTRODUCTION

Frailty is an emerging and newly recognized complication of diabetes in older people. However, frailty is not thoroughly investigated in diabetes outcome studies.

AREAS COVERED

This manuscript reviews the effect of glycemic control and hypoglycemic therapy on the incidence of frailty in older people with diabetes.

EXPERT OPINION

Current studies show that both low glycemia and high glycemia are associated with frailty. However, most of the studies, especially low glycemia studies, are cross-sectional or retrospective, suggesting association, rather than causation, of frailty. In addition, frail patients in the low glycemia studies are characterized by lower body weight or lower body mass index (BMI), contrary to those in the high glycemia studies, who are either overweight or obese. This may suggest that frailty has a heterogeneous metabolic spectrum, starting with an anorexic malnourished (AM) phenotype at one end, which is associated with low glycemia and a sarcopenic obese (SO) phenotype on the other end, which is associated with high glycemia. The current little evidence suggests that poor glycemic control increases the risk of frailty, but there is a paucity of evidence to suggest that tight glycemic control would reduce the risk of incident frailty. Metformin is the only well-studied hypoglycemic agent, so far, to have a protective effect against frailty independent of glycemic control in the non-frail older people with diabetes. However, once frailty is developed, the choice of the best hypoglycemic agent for these patients will be affected by the metabolic phenotype of frailty. For example, sodium glucose transporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RA) are appropriate in the SO phenotype due to their weight losing properties, while insulin therapy may be considered early in the AM phenotype due to its anabolic and weight gaining benefits. Future studies are still required to further investigate the metabolic effects of frailty on older people with diabetes, determine the most appropriate HbA1c target, and explore the most suitable hypoglycemic agent in each metabolic phenotype of frailty.