Effects of Diabetes Mellitus on Cognitive Decline in Patients with Alzheimer Disease: A Systematic Review

Diabetes, antidiabetic medications and risk of dementia: A systematic umbrella review and meta-analysis

AIMS

The objective of this umbrella review and meta-analysis was to evaluate the effect of diabetes on risk of dementia, as well as the mitigating effect of antidiabetic treatments.

MATERIALS AND METHODS

We conducted a systematic umbrella review on diabetes and its treatment, and a meta-analysis focusing on treatment. We searched MEDLINE/PubMed, Embase, PsycINFO, CINAHL and the Cochrane Library for systematic reviews and meta-analyses assessing the risk of cognitive decline/dementia in individuals with diabetes until 2 July 2023. We conducted random-effects meta-analyses to obtain risk ratios and 95% confidence intervals estimating the association of metformin, thiazolidinediones, pioglitazone, dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors, meglitinides, insulin, sulphonylureas, glucagon-like peptide-1 receptor agonists (GLP1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) with risk of dementia from cohort/case-control studies. The subgroups analysed included country and world region. Risk of bias was assessed with the AMSTAR tool and Newcastle-Ottawa Scale.

RESULTS

We included 100 reviews and 27 cohort/case-control studies (N = 3 046 661). Metformin, thiazolidinediones, pioglitazone, GLP1RAs and SGLT2is were associated with significant reduction in risk of dementia. When studies examining metformin were divided by country, the only significant effect was for the United States. Moreover, the effect of metformin was significant in Western but not Eastern populations. No significant effect was observed for dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors, or insulin, while meglitinides and sulphonylureas were associated with increased risk.

CONCLUSIONS

Metformin, thiazolidinediones, pioglitazone, GLP1RAs and SGLT2is were associated with reduced risk of dementia. More longitudinal studies aimed at determining their relative benefit in different populations should be conducted.

Diabetes mellitus type 2 as an underlying, comorbid or consequent state of mental disorders

Somatic disturbances that occur in parallel with psychiatric diseases are a major challenge in clinical practice. Various factors contribute to the development of mental and somatic disorders. Type 2 diabetes mellitus (T2DM) is a significant health burden worldwide, and the prevalence of diabetes in adults is increasing. The comorbidity of diabetes and mental disorders is very common. By sharing a bidirectional link, both T2DM and mental disorders influence each other in various manners, but the exact mechanisms underlying this link are not yet elucidated. The potential mechanisms of both mental disorders and T2DM are related to immune and inflammatory system dysfunction, oxidative stress, endothelial dysfunction, and metabolic disturbances. Moreover, diabetes is also a risk factor for cognitive dysfunction that can range from subtle diabetes-associated cognitive decline to pre-dementia and dementia. A complex re-lationship between the gut and the brain also represents a new therapeutic approach since gut-brain signalling pathways regulate food intake and hepatic glucose production. The aim of this minireview is to summarize and present the latest data on mutual pathogenic pathways in these disorders, emphasizing their complexity and interweaving. We also focused on the cognitive performances and changes in neurodegenerative disorders. The importance of implementing integrated approaches in treating both of these states is highlighted, along with the need for individual therapeutic strategies.

Hippocampal GFAP-positive astrocyte responses to amyloid and tau pathologies

INTRODUCTION

In Alzheimer's disease clinical research, glial fibrillary acidic protein (GFAP) released/leaked into the cerebrospinal fluid and blood is widely measured and perceived as a biomarker of reactive astrogliosis. However, it was demonstrated that GFAP levels differ in individuals presenting with amyloid-β (Aβ) or tau pathologies. The molecular underpinnings behind this specificity are little explored. Here we investigated biomarker and transcriptomic associations of hippocampal GFAP-positive astrocytes with Aβ and tau pathologies in humans and mouse models.

METHODS

We studied 90 individuals with plasma GFAP, Aβ- and Tau-PET to investigate the association between biomarkers. Then, transcriptomic analysis in hippocampal GFAP-positive astrocytes isolated from mouse models presenting Aβ (PS2APP) or tau (P301S) pathologies was conducted to explore differentially expressed genes (DEGs), Gene Ontology terms, and protein-protein interaction networks associated with each phenotype.

RESULTS

In humans, we found that plasma GFAP associates with Aβ but not tau pathology. Unveiling the unique nature of hippocampal GFAP-positive astrocytic responses to Aβ or tau pathologies, mouse transcriptomics showed scarce overlap of DEGs between the Aβ. and tau mouse models. While Aβ GFAP-positive astrocytes were overrepresented with DEGs associated with proteostasis and exocytosis-related processes, tau hippocampal GFAP-positive astrocytes presented greater abnormalities in functions related to DNA/RNA processing and cytoskeleton dynamics.

CONCLUSION

Our results offer insights into Aβ- and tau-driven specific signatures in hippocampal GFAP-positive astrocytes. Characterizing how different underlying pathologies distinctly influence astrocyte responses is critical for the biological interpretation of astrocyte biomarkers and suggests the need to develop context-specific astrocyte targets to study AD.

FUNDING

This study was supported by Instituto Serrapilheira, Alzheimer's Association, CAPES, CNPq and FAPERGS.

A novel approach to type 3 diabetes mechanism: The interplay between noncoding RNAs and insulin signaling pathway in Alzheimer's disease

Today, growing evidence indicates that patients with type 2 diabetes (T2D) are at a higher risk of developing Alzheimer's disease (AD). Indeed, AD as one of the main causes of dementia in people aged more than 65 years can be aggravated by insulin resistance (IR) and other metabolic risk factors related to T2D which are also linked to the function of the brain. Remarkably, a new term called "type 3 diabetes" has been suggested for those people who are diagnosed with AD while also showing the symptoms of IR and T2D. In this regard, the role of genetic and epigenetic changes associated with AD has been confirmed by many studies. On the other hand, it should be noted that the insulin signaling pathway is highly regulated by various mechanisms, including epigenetic factors. Among these, the role of noncoding RNAs (ncRNAs), including microRNAs and long noncoding RNAs has been comprehensively studied with respect to the pathology of AD and the most well-known underlying mechanisms. Nevertheless, the number of studies exploring the association between ncRNAs and the downstream targets of the insulin signaling pathway in the development of AD has notably increased in recent years. With this in view, the present study aimed to review the interplay between different ncRNAs and the insulin signaling pathway targets in the pathogenesis of AD to find a new approach in the field of combining biomarkers or therapeutic targets for this disease.

Effects of Artemisia macrocephala Jacquem on Memory Deficits and Brain Oxidative Stress in Streptozotocin-Induced Diabetic Mice

Different species of Artemisia have been reported to have therapeutic potential in treating various health disorders, including diabetes and memory dysfunction. The present study was planned to evaluate the effects of Artemisia macrocephala Jacquem crude extract and its subfractions as antiamnesic agents in streptozotocin-induced (STZ) diabetic mice. The in vivo behavioral studies were performed using the Y Maze test and novel object recognition test (NORT) test at doses of 100 and 200 mg/kg of crude extract and 75 and 150 mg/kg of fractions. The in vitro and ex vivo anticholinesterase activities, along with biochemical parameters (superoxide dismutase, catalase, glutathione and lipid peroxidation) in the brain, were evaluated. Blood glucose levels were monitored with a glucometer; crude extract and fractions reduced the glucose level considerably, with some differences in the extent of their efficacies. The crude extract and fractions demonstrated significant inhibitory activity against cholinesterases (AChE and BuChE) in vitro. Crude, chloroform and ethyl acetate extract were found to be more potent than the other fractions, with IC50 of Crd-Am = 116.36 ± 1.48 and 240.52 ± 1.35 µg/mL, Chl-Am = 52.68 ± 1.09 and 57.45 ± 1.39 µg/mL and Et-Am = 75.19 ± 1.02 and 116.58 ± 1.09 µg/mL, respectively. Oxidative stress biomarkers like superoxide dismutase, catalase and glutathione levels were elevated, whereas MDA levels were reduced by crude extract and all fractions with little difference in their respective values. The Y-maze test and novel object recognition test demonstrated declines in memory impairment in groups (n = 6) treated with crude extract and fractions as compared to STZ diabetic (amnesic) group. The most active fraction, Chl-Am, was also subjected to isolation of bioactive compounds; three compounds were obtained in pure state and designated as AB-I, AB-II and AB-III. Overall, the results of the study showed that Artemisia macrocephala Jacquem enhanced the memory impairment associated with diabetes, elevated acetylcholine levels and ameliorated oxidative stress. Further studies are needed to explore the beneficial role of the secondary metabolites isolated in the present study as memory enhancers. Toxicological aspects of the extracts are also important and need to be evaluated in other animal models.

Remembering your A, B, C's: Alzheimer's disease and ABCA1

The function of ATP binding cassette protein A1 (ABCA1) is central to cholesterol mobilization. Reduced ABCA1 expression or activity is implicated in Alzheimer's disease (AD) and other disorders. Therapeutic approaches to boost ABCA1 activity have yet to be translated successfully to the clinic. The risk factors for AD development and progression, including comorbid disorders such as type 2 diabetes and cardiovascular disease, highlight the intersection of cholesterol transport and inflammation. Upregulation of ABCA1 can positively impact APOE lipidation, insulin sensitivity, peripheral vascular and blood–brain barrier integrity, and anti-inflammatory signaling. Various strategies towards ABCA1-boosting compounds have been described, with a bias toward nuclear hormone receptor (NHR) agonists. These agonists display beneficial preclinical effects; however, important side effects have limited development. In particular, ligands that bind liver X receptor (LXR), the primary NHR that controls ABCA1 expression, have shown positive effects in AD mouse models; however, lipogenesis and unwanted increases in triglyceride production are often observed. The longstanding approach, focusing on LXRβ vs. LXRα selectivity, is over-simplistic and has failed. Novel approaches such as phenotypic screening may lead to small molecule NHR modulators that elevate ABCA1 function without inducing lipogenesis and are clinically translatable.

Sweet Memories or Not? A Comparative Study on Cognitive Impairment in Diabetes Mellitus

Introduction

Type 2 Diabetes Mellitus is a modern-day epidemic and dementia has been declared as a global challenge. It is, therefore, worthwhile to investigate the effect that Diabetes has on cognition. Although effective screening is routinely carried out for various complications of Diabetes, its effect on Higher Mental Functions is often overlooked.

Methodology

A cross-sectional analytical study to assess Cognitive Impairment was carried out on 800 participants, 400 diabetics and 400 non-diabetics attending a tertiary care center. The Addenbrooke's Cognitive Examination- III was used, which is a validated, highly sensitive tool having a maximum score of 100. Patients with a score < /= 82 were considered to have impaired Cognition. Statistical analysis was done using SPSSv.21. Suitable statistical tests like Mann–Whitney U, t-test, ROC curve and Logistic regression analysis were done.

Results

Cognitive Impairment was present in 63.8% of the diabetics when compared to only 10.8% in the non-diabetics, with an Odds Ratio-8.78 (CI-4.47–17.22). The total ACE score in diabetics [median-82 (IQR-4), mean rank-270.06] was less compared to the non-diabetic patients [median- 85 (IQR-3), mean rank-530.94] (U = 27822, p-0.001). Attention, Memory, Language, and Visuospatial domains were significantly lower in the diabetics compared to the non-diabetics. However, the fluency domain was not affected. Hypertension and the presence of macrovascular diseases were significantly associated with Cognitive Impairment (p < 0.005). Those with Cognitive dysfunction also had higher mean RBS values and longer duration of Diabetes (p-0.001). The cut-off value for RBS (to distinguish people with and without Cognitive Impairment) from ROC curve was 142.5 (AUC = 0.834, Youden's Index-0.586, p-0.001) and for duration of Diabetes was 7.5 years (AUC = 0.847, Youden's Index-0.529, p-0.001).

Conclusion

This paper highlights that Cognitive Impairment exists in a very high proportion of diabetic patients in Kerala. So, it is important that we do an early assessment of cognitive function in diabetes patients and manage them prudently. Early interventions may prove to be beneficial in the long run, considering the burden of diabetes and cognitive dysfunction associated with the disease.

Comparison of cognitive status of diabetic and non-diabetic elderly in the last ten years in primary health care in Iran

Introduction. Cognitive disorders and chronic diseases such as diabetes are common problems of aging. The aim of this study was to determine and compare the cognitive status of diabetic and non-diabetic elderly in the past ten years in primary health care in Iran. Method: This cross-sectional study was performed on people aged 60 years and older in Kerman, Iran in 2020. In total, this study was performed on 200 patients (100 diabetic and 100 non-diabetic) meeting inclusion criteria. The Short Mental Status Questionnaire (MMSE) and The Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) were used to assess cognitive function. The validity and reliability of the questionnaires were confirmed in this study. Data were analyzed using Chi-square, T-test, and ANOVA analysis in SPSS 21 software. Results. The results showed that there was a statistically significant difference between diabetic and non-diabetic groups in the current cognitive status and cognitive status in the last ten years. The mean scores of cognitive function from the short mental status questionnaire in the diabetic group were lower than in the non-diabetic group (p = 0.001). The mean scores of the cognitive deficit screening questionnaire in diabetic elderly were higher than in non-diabetic elderly (p < 0.001). Conclusion. Based on the results of this study, health care providers and family physicians should focus on controlling diabetes and identifying any cognitive impairment in the early stages of comprehensive care of diabetic patients.

A Comparison of Behavioral and Psychological Symptoms of Dementia (BPSD) and BPSD Sub-Syndromes in Early-Onset and Late-Onset Alzheimer's Disease

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) have a large impact on the quality of life of patients with Alzheimer's disease (AD). Few studies have compared BPSD between early-onset (EOAD) and late-onset (LOAD) patients, finding conflicting results.

OBJECTIVE

The aims of this study were to: 1) characterize the presence, overall prevalence, and time of occurrence of BPSD in EOAD versus LOAD; 2) estimate the prevalence over time and severity of each BPSD in EOAD versus LOAD in three stages: pre-T0 (before the onset of the disease), T0 (from onset to 5 years), and T1 (from 5 years onwards); 3) track the manifestation of BPSD sub-syndromes (i.e., hyperactivity, psychosis, affective, and apathy) in EOAD versus LOAD at T0 and T1.

METHODS

The sample includes 1,538 LOAD and 387 EOAD diagnosed from 1996 to 2018. Comprehensive assessment batteries, including the Neuropsychiatric Inventory (NPI), were administered at the first medical assessment and at different follow-up period.

RESULTS

The overall prevalence for the most of BPSD was significantly higher in EOAD compared to LOAD whereas most BPSD appeared significantly later in EOAD patients. Between the two groups, from pre-T0 to T1 we recorded a different pattern of BPSD prevalence over time as well as for BPSD sub-syndromes at T0 and T1. Results on severity of BPSD did not show significant differences.

CONCLUSION

EOAD and LOAD represent two different forms of a single entity not only from a neuropathological, cognitive, and functional level but also from a psychiatric point of view.

Diabetes/Dementia in Sub-saharian Africa and Nigerian Women in the Eye of Storm

In the next few years, the prevalence of diabetes mellitus (DM) is projected to dramatically increase globally, but most of the cases will occur in low-to-middle-income countries. Some of the major risk factors for diabetes accelerate the development of dementia in African-Americans, thus leading to a higher prevalence of dementia than Caucasians. Sub-Saharan Africa women have a disproportionately two-to-eight fold increased prevalence of dementia. In the eye of this storm, Nigeria holds the highest number of diabetics on the African continent, and its prevalence is rising in parallel to obesity, hypertension, and the population's aging. The socio-economic impact of the rising prevalence of DM and dementia will be huge and unsustainable for the healthcare system in Nigeria, as has been recognized in developed economies. Here, we analyze the current situation of women's health in Nigeria and explore future perspectives and directions. The complex interplay of factors involved in diabetes and dementia in Nigerian women include key biological agents (metabolic syndrome, vascular damage, inflammation, oxidative stress, insulin resistance), nutritional habits, lifestyle, and anemia, that worsen with comorbidities. In addition, restricted resources, lack of visibility, and poor management result in a painful chain that increases the risk and burden of disease in Nigerian women from youth to elderly ages. Heath policies to increase the ra- tio of mental health professionals per number of patients, mostly in rural areas, foment of proactive primary care centers, and interventions targeting adolescents and adult women and other specific mothers-children pairs are strongly required for a sustainable development goal.

Differential effects of risk factors on the cognitive trajectory of early- and late-onset Alzheimer's disease

BACKGROUND

Although few studies have shown that risk factors for Alzheimer's disease (AD) are associated with cognitive decline in AD, not much is known whether the impact of risk factors differs between early-onset AD (EOAD, symptom onset < 65 years of age) versus late-onset AD (LOAD). Therefore, we evaluated whether the impact of Alzheimer's disease (AD) risk factors on cognitive trajectories differ in EOAD and LOAD.

METHODS

We followed-up 193 EOAD and 476 LOAD patients without known autosomal dominant AD mutation for 32.3 ± 23.2 months. Mixed-effects model analyses were performed to evaluate the effects of APOE ε4, low education, hypertension, diabetes, dyslipidemia, and obesity on cognitive trajectories.

RESULTS

APOE ε4 carriers showed slower cognitive decline in general cognitive function, language, and memory domains than APOE ε4 carriers in EOAD but not in LOAD. Although patients with low education showed slower cognitive decline than patients with high education in both EOAD and LOAD, the effect was stronger in EOAD, specifically in frontal-executive function. Patients with hypertension showed faster cognitive decline than did patients without hypertension in frontal-executive and general cognitive function in LOAD but not in EOAD. Patients with obesity showed slower decline in general cognitive function than non-obese patients in EOAD but not in LOAD.

CONCLUSIONS

Known risk factors for AD were associated with slower cognitive decline in EOAD but rapid cognitive decline in LOAD.

Air Pollution Is Associated with Cognitive Deterioration of Alzheimer's Disease

INTRODUCTION

Dementia is one of the major causes of disability and dependency among older people worldwide. Alz-heimer's disease (AD), the most common cause of dementia among the elderly, has great impact on the health-care system of developed nations. Several risk factors are suggestive of an increased risk of AD, including APOE-ε4, male, age, diabetes mellitus, hypertension, and low social engagement. However, data on risk factors of AD progression are limited. Air pollution is revealed to be associated with increasing dementia incidence, but the relationship between air pollution and clinical AD cognitive deterioration is unclear.

METHODS

We conducted a case-control and city-to-city study to compare the progression of AD patients in different level of air-polluted cities. Clinical data of a total of 704 AD patients were retrospectively collected, 584 residences in Kaohsiung and 120 residences in Pingtung between 2002 and 2018. An annual interview was performed with each patient, and the Clinical Dementia Rating score (0 [normal] to 3 [severe stage]) was used to evaluate their cognitive deterioration. Air pollution data of Kaohsiung and Pingtung city for 2002-2018 were retrieved from Taiwan Environmental Protection Administration. Annual Pollutant Standards Index (PSI) and concentrations of particulate matter (PM10), sulfur dioxide (SO2), ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO) were obtained.

RESULTS

The PSI was higher in Kaohsiung and compared with Pingtung patients, Kaohsiung patients were exposed to higher average annual concentrations of CO, NO2, PM10, and SO2. AD patients living in Kaohsiung suffered from faster cognitive deterioration in comparison with Pingtung patients (log-rank test: p = 0.016). When using multivariate Cox proportional hazards regression analysis, higher levels of CO, NO2, PM10, and SO2 exposure were associated with increased risk of AD cognitive deterioration. Among all these air pollutants, high SO2 exposure has the greatest impact while O3 has a neutral effect on AD cognitive deterioration.

CONCLUSIONS

Air pollution is an environment-related risk factor that can be controlled and is associated with cognitive deterioration of AD. This finding could contribute to the implementation of public intervention strategies of AD.

Co-administration of berberine/gypenosides/bifendate ameliorates metabolic disturbance but not memory impairment in type 2 diabetic mice

Cognitive impairment is a well-known complication of Type 2 diabetes mellitus (T2DM) characterized by cellular insulin resistance, chronic inflammation, and metabolic disturbances. Berberine, gypenosides and bifendate are traditional Chinese herbal medicines with multiple pharmacological activities including anti-inflammation, anti-oxidant, metabolism improvement and memory improvement. To investigate whether they have synergistic effect on T2DM metabolic syndrome and associated memory impairment, we measured in this study the effect of a low dose of berberine/gypenosides/bifendate (BGB) co-administration on metabolism and memory performance of T2DM model mice. We found that BGB co-administration ameliorated metabolic abnormalities of both high-fat diet/streptozotocin (STZ)-induced T2DM mice and db/db mice. However, it did not alleviate memory impairment in either type of T2DM model mice. Since neither berberine, gypenosides nor bifendate alone at the low dose is effective, we presume that BGB co-administration has synergistic action on T2DM metabolic syndrome. In addition, our findings suggest that higher doses of BGB might be required to ameliorate memory impairment than metabolic disturbance associated with T2DM.

Investigations into the Role of Metabolism in the Inflammatory Response of BV2 Microglial Cells

Although the hallmarks of Alzheimer's disease (AD) are amyloid beta plaques and neurofibrillary tangles, there is growing evidence that neuroinflammation, mitochondrial dysfunction and oxidative stress play important roles in disease development and progression. A major risk factor for the development of AD is diabetes, which is also characterized by oxidative stress and mitochondrial dysfunction along with chronic, low-grade inflammation. Increasing evidence indicates that in immune cells, the induction of a pro-inflammatory phenotype is associated with a shift from oxidative phosphorylation (OXPHOS) to glycolysis. However, whether hyperglycemia also contributes to this shift is not clear. Several different approaches including culturing BV2 microglial cells in different carbon sources, using enzyme inhibitors and knocking down key pathway elements were used in conjunction with bacterial lipopolysaccharide (LPS) activation to address this question. The results indicate that while high glucose favors NO production, pro-inflammatory cytokine production is highest in the presence of carbon sources that drive OXPHOS. In addition, among the carbon sources that drive OXPHOS, glutamine is a very potent inducer of IL6 production. This effect is dampened in the presence of glucose. Together, these results may provide new prospects for the therapeutic manipulation of neuroinflammation in the context of diabetes and AD.

Association between vascular measures and cognitive function in type 2 diabetes

AIM

To examine correlation between vascular measures and cognitive performance in type 2 diabetes (T2D).

METHODS

This was a cross-sectional study on patients (N = 1167) aged ≥45 years attending Diabetes Centre in a tertiary hospital and primary care polyclinic. The following vascular measures were measured: systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), pulse wave velocity (PWV) and augmentation index (AI). Cognition was assessed by Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Multiple linear regression was used to examine relationships between vascular measures and cognition, adjusting for demographics, education, depression, clinical covariates and presence of APOE _Ɛ4 allele.

RESULTS

In unadjusted analyses, all the vascular measures, except for MAP, were associated with RBANS total score. In fully adjusted analyses, the association with RBANS total score persisted for peripheral PP, aortic PP and aortic DBP with βs -0.05 (95%CI -0.07 to -0.02; p = 0.001), -0.04 (95%CI -0.06 to -0.01; p = 0.002) and 0.05 (95%CI 0.00 to 0.09; p = 0.033). Association between peripheral and aortic PP and RBANS total score was unaffected by age-stratification (age <60 and ≥60 years). In contrast, significant association between aortic DBP and RBANS total score was only observed for those ≥60 years. Peripheral and aortic PP (which estimate pulsatility) are negatively associated with attention, visuospatial/constructional and language ability.

CONCLUSIONS

Peripheral and aortic PP, and aortic DBP were independently correlated with cognitive performance globally and in multiple domains. Further research should be conducted to establish the clinical relevance and importance.

Effect of Advanced Glycation End Products on the Progression of Alzheimer's Disease

BACKGROUND

Shared links between type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) have been well-known. A high concentration of advanced glycation end products (AGEs) has been reported to contribute to impaired mobility in patients with AD, but there is limited understanding regarding the longitudinal impact of AGEs on cognitive performance.

OBJECTIVE

This study aims to explore whether the concentrations of AGEs mediate the clinical progression of cognitive performance in patients with AD and T2DM.

METHODS

Twenty-five patients aged 79.0±5.8 years who were diagnosed with probable AD with a Clinical Dementia Rating (CDR) of 0.5 or 1 and T2DM were enrolled in this study. When patients participated in the study, the concentration of plasma AGEs was tested. A series of neuropsychological tests, namely the Mini-Mental Status Examination (MMSE), Cognitive Assessment Screening Instrument (CASI), and CDR, were performed annually during follow-up. The association between the concentration of AGEs and changes in overall cognition and cognition related daily living performance was analyzed.

RESULTS

After the mean 48.6±2.1 months of follow-up, AGEs were found to be significantly associated with a change in CDR. A total of 12 (48%) patients experienced a decline in CDR; they had a significantly higher concentration of AGEs than did those whose CDR did not deteriorate (100.5 ± 14.2 versus 81.5 ± 17.7; p = 0.007). This difference in CDR remained significant after adjustment for age, sex, education level, and apolipoprotein E4 status (adjusted p = 0.023).

CONCLUSION

In conclusion, this study indicates that a high concentration of AGEs may be a predictor of a long-term decline in cognition related daily living performance in patients with AD and T2DM.

Hypertension and Age-Related Cognitive Impairment: Common Risk Factors and a Role for Precision Aging

Purpose of Review

Precision Aging® is a novel concept that we have recently employed to describe how the model of precision medicine can be used to understand and define the multivariate risks that drive age-related cognitive impairment (ARCI). Hypertension and cardiovascular disease are key risk factors for both brain function and cognitive aging. In this review, we will discuss the common mechanisms underlying the risk factors for both hypertension and ARCI and how the convergence of these mechanisms may be amplified in an individual to drive changes in brain health and accelerate cognitive decline.

Recent Findings

Currently, our cognitive health span does not match our life span. Age-related cognitive impairment and preventing and treating ARCI will require an in-depth understanding of the interrelated risk factors, including individual genetic profiles, that affect brain health and brain aging. Hypertension and cardiovascular disease are important risk factors for ARCI. And, many of the risk factors for developing hypertension, such as diabetes, smoking, stress, viral infection, and age, are shared with the development of ARCI. We must first understand the mechanisms common to the converging risk factors in hypertension and ARCI and then design person-specific therapies to optimize individual brain health.

Summary

The understanding of the convergence of shared risk factors between hypertension and ARCI is required to develop individualized interventions to optimize brain health across the life span. We will conclude with a discussion of possible steps that may be taken to decrease ARCI and optimize an individual’s cognitive life span.

The association between diabetes and cognitive changes during aging

BACKGROUND

Worldwide, we are observing a rising prevalence of dementia and mild cognitive impairments that often co-occur with the heightened incidence of non-communicable diseases in the elderly. It is suggested that type 2 diabetes and defects in glucose metabolism might predispose to poorer cognitive performances and more rapid decline in old age.

METHODS

to address existing knowledge gaps in this area, we systematically reviewed the literature to identify whether patients with type 2 diabetes (T2DM) and pre-diabetes are at a higher risk of poorer cognitive performance, and whether the risk (if any) might affect specific cognitive abilities. We concentrated the review on elderly individuals (65 years or older) at intake. In total, 3251 original articles were retrieved, of which 17 met our inclusion and quality control criteria, which comprised 12 structured questions used to define the articles.

RESULTS

11 of 17 studies found a statistically significant decline in cognition among individuals who had T2DM or pre-diabetes compared to their non-diabetic counterparts. The association between diabetes and cognitive decline was not always clear, and the extent of the cognitive tests used seemed to have the greatest effect on the results.

CONCLUSION

Focusing on a population age 65 years and over, we found insufficient evidence to support an association between pre-diabetes stages and mild cognitive impairment. However, there is consistent evidence to support diabetes as an independent risk factor for low cognitive ability in the elderly. Finally, we found insufficient evidence to support effect of T2DM on distinct cognitive ability due to the scarcity of comparable findings.

Altered plasma visfatin levels and insulin resistance in patients with Alzheimer's disease

Central insulin resistance is involved in the pathophysiology of Alzheimer's disease (AD). Visfatin (VIS), an adipokine secreted from peripheral adipose tissue, is involved in energy balance and weight control. Besides its metabolic roles, VIS possesses insulin-mimetic, anti-apoptotic, and neuroprotective properties. In this study, we assessed the presence of a correlation between plasma VIS level and insulin resistance or AD. Sixty participants were enrolled in this study; 34 patients with AD and 26 healthy subjects. All subjects underwent comprehensive evaluations including Mini-mental score exam (MMSE) for the diagnosis of dementia. Subjects with MMSE score < 24 were added to the AD group, while healthy subjects should have a MMSE score > 27. Fasting blood sugar (FBS) and insulin levels were measured by enzyme-linked immunosorbent assay. The results indicate a significant elevation in FBS from 103 ± 3.0 to 147 ± 7.6 in AD patients (p ≤ 0.001). Additionally, 71% of AD patients developed insulin resistance, as the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index increased from 2.9 ± 0.5 in healthy subjects to 5.2 ± 0.7 in AD patients (p ≤ 0.05). Body mass index and serum insulin level did not show a significant alteration, but serum VIS levels were significantly (p ≤ 0.01) lower in AD patients (11.15 ± 1.9 ng/ml) in comparison to control group (21.09 ± 2.3 ng/ml). There is a negative correlation between plasma VIS level and the HOMA-IR index (p < 0.05). The results of this study present clear evidence for systemic insulin resistance and decreased serum VIS level in non-obese, non-overweight patients with moderate to severe AD.

Potential Biochemical Mechanisms of Brain Injury in Diabetes Mellitus

The goal of this review was to summarize current biochemical mechanisms of and risk factors for diabetic brain injury. We mainly summarized mechanisms published in the past three years and focused on diabetes induced cognitive impairment, diabetes-linked Alzheimer’s disease, and diabetic stroke. We think there is a need to conduct further studies with increased sample sizes and prolonged period of follow-ups to clarify the effect of DM on brain dysfunction. Additionally, we also think that enhancing experimental reproducibility using animal models in conjunction with application of advanced devices should be considered when new experiments are designed. It is expected that further investigation of the underlying mechanisms of diabetic cognitive impairment will provide novel insights into therapeutic approaches for ameliorating diabetes-associated injury in the brain.

Glycosylated hemoglobin level, race/ethnicity, and cognition in midlife and early old age

Empirical evidence linking racial/ethnic differences in glycosylated hemoglobin levels (HbA1c) to cognitive function in midlife and early old age is limited. We use biomarker data from the Health and Retirement Study (HRS, 2006-2014), on adults 50-64 years at baseline (57-73 years by 2014), and fit multinomial logistic regression models to assess the association between baseline HbA1c, cognitive function (using Langa-Weir classifications) and mortality across 8-years. Additionally, we test for modification effects by race/ethnicity. In age- and sex-adjusted models high HbA1c level was associated with lower baseline cognition and higher relative risk ratios (RRR; vs. normal cognition) for cognitive impairment no dementia (CIND; RRR= 2.3; 95%CI=[1.38;3.84]; p<0.01), and dementia (RRR= 4.00; 95%CI=[1.76;9.10]; p<0.01). Adjusting for sociodemographic, behavioral risk factors, and other health conditions explained the higher RRR for CIND and attenuated the RRR for dementia by approximately 30%. HbA1c levels were not linked to the slope of cognitive decline, and we found no evidence of modification effects for HbA1c by race/ethnicity. Targeting interventions for glycemic control in the critical midlife period can protect baseline cognition and buffer against downstream development of cognitive impairment. This can yield important public health benefits and reductions in burdens associated with cognitive impairment, particularly among race/ethnic minorities who are at higher risk for metabolic diseases.

Mild Cognitive Impairment Subtypes and Type 2 Diabetes in Elderly Subjects

Background: Type 2 diabetes (T2D) is correlated to amnestic mild cognitive impairment (aMCI) and to non-amnestic mild cognitive impairment (naMCI). This study evaluated whether the T2D variable characterizes a peculiar cognitive profile in elderly patients. Moreover, it explores the association between glycated hemoglobin levels (HbA1c), T2D duration, insulin and oral hypoglycemic agent treatment, and cognition in elderly diabetic patients. Methods: Detailed neuropsychological battery was used to diagnose MCI subtypes. A total of 39 MCI subjects with T2D (T2D-MCI) and 37 MCI subjects without T2D (ND-MCI), matched for age, educational level, and Mini-Mental State Examination score, were included. Results: ND-MCI performed worse in memory and language domains than T2D-MCI. The amnestic subtype is more frequent among ND-MCI and non-amnestic subtype in T2D-MCI. In T2D-MCI, high HbA1c levels correlate with episodic memory (immediate recall) and T2D duration. Some indexes of episodic memory (immediate recall), attention, and visual-spatial ability correlate with insulin treatment. Conclusions: An association between T2D and non-amnestic MCI is suggested. In the T2D-MCI group, significant associations between insulin treatment and memory (immediate recall), complex figure copy, and attention were found.

Analysis of Functional and Cognitive Impairment in Institutionalized Individuals with Movement Disorders

BACKGROUND

Many neurological disorders lead to institutionalization and can be accompanied in their advanced stages by functional impairment, and progressive loss of mobility, and cognitive alterations.

OBJECTIVE

We analyzed the relationship between functional impairment and cognitive performance and its related subdomains in individuals with Parkinson's disease, Alzheimer's disease accompanied by motor dysfunction, and with other neurological disorders characterized by both motor and cognitive problems.

METHODS

All participants lived in nursing homes (Valencia, Spain) and underwent cognitive evaluation with the Mini-Mental State Examination; functional assessment of independence in activities of daily living using the Barthel score and Katz index; and assessment of mobility with the elderly mobility scale.

RESULTS

The mean age of the subjects was 82.8 ± 0.6 years, 47% of the sample included individuals with Parkinson's disease, and 48 % of the sample presented severe cognitive impairment. Direct significant relationships were found between the level of cognitive impairment and functional capacity (p < 0.01) and mobility (p < 0.05). Among the different domains, memory impairment was not associated with altered activities of daily living or mobility. The functional impairment and the risk of severe cognitive impairment were significantly (p<0.05) higher in female compared to male patients. Among comorbidities, overweight/obesity and diabetes were significantly (p < 0.05) associated with poor cognitive performance in those individuals with mild/moderate cognitive impairment.

CONCLUSION

In institutionalized individuals with movement disorders there is an association between functional and cognitive impairment. Reduction of over-weight and proper control of diabetes may represent novel targets for improving cognitive function at such early stages.

Mild cognitive impairment understanding: an empirical study by data-driven approach

Background

Cognitive decline has emerged as a significant threat to both public health and personal welfare, and mild cognitive decline/impairment (MCI) can further develop into Dementia/Alzheimer’s disease. While treatment of Dementia/Alzheimer’s disease can be expensive and ineffective sometimes, the prevention of MCI by identifying modifiable risk factors is a complementary and effective strategy.

Results

In this study, based on the data collected by Centers for Disease Control and Prevention (CDC) through the nationwide telephone survey, we apply a data-driven approach to re-exam the previously founded risk factors and discover new risk factors. We found that depression, physical health, cigarette usage, education level, and sleep time play an important role in cognitive decline, which is consistent with the previous discovery. Besides that, the first time, we point out that other factors such as arthritis, pulmonary disease, stroke, asthma, marital status also contribute to MCI risk, which is less exploited previously. We also incorporate some machine learning and deep learning algorithms to weigh the importance of various factors contributed to MCI and predicted cognitive declined.

Conclusion

By incorporating the data-driven approach, we can determine that risk factors significantly correlated with diseases. These correlations could also be expanded to another medical diagnosis besides MCI.

The Association Between Diabetes and Cognitive Function in Later Life

Introduction:

Although diabetes through several possible mechanisms such as increased microvascular pathology and inefficiency of glucose utilization during cognitive tasks can be associated with cognitive impairment, there is inconclusive evidence that shows elderly diabetic patients under therapy have higher cognitive function compared to their non-diabetics counterparts. The present study was conducted to elucidate the association between diabetes and cognitive function in later life.

Methods:

Data for this study, consisting of 2202 older adults aged 60 years and above, were taken from a population-based survey entitled “Identifying Psychosocial and Identifying Economic Risk Factor of Cognitive Impairment among Elderly. Data analysis was conducted using the IBM SPSS Version 23.0.

Results:

The mean of MMSE was found to be 22.67 (SD = 4.93). The overall prevalence of self-reported diabetes was found to be 23.6% (CI95%: 21.8% - 25.4%). The result of independent t-test showed diabetic subjects had a higher mean score of MMSE (M = 23.05, SD =4 .55) than their counterparts without diabetes (M = 22.55, SD = 5.04) (t = -2.13 p<.05). The results of multiple linear regression analysis showed that diabetes was not significantly associated with cognitive function, after controlling the possible confounding factors.

Conclusions:

The findings from the current study revealed that diabetes is not associated with cognitive decline. This study supports the findings that long-term treatment of diabetes may reduce the risk of cognitive decline. This finding may provide new opportunities for the prevention and management of cognitive decline.

Diabetes Mellitus and Cause-Specific Mortality: A Population-Based Study

BACKGROUND

To investigate whether diabetes contributes to mortality for major types of diseases.

METHODS

Six National Health and Nutrition Examination Survey data cycles (1999 to 2000, 2001 to 2002, 2003 to 2004, 2005 to 2006, 2007 to 2008, and 2009 to 2010) and their linked mortality files were used. A population of 15,513 participants was included according to the availability of diabetes and mortality status.

RESULTS

Participants with diabetes tended to have higher all-cause mortality and mortality due to cardiovascular disease, cancer, chronic lower respiratory diseases, cerebrovascular disease, influenza and pneumonia, and kidney disease. Confounder-adjusted Cox proportional hazard models showed that both diagnosed diabetes category (yes or no) and diabetes status (diabetes, prediabetes, or no diabetes) were associated with all-cause mortality and with mortality due to cardiovascular disease, chronic lower respiratory diseases, influenza and pneumonia, and kidney disease. No associations were found for cancer-, accidents-, or Alzheimer's disease-related mortality.

CONCLUSION

The current study's findings provide epidemiological evidence that diagnosed diabetes at the baseline is associated with increased mortality risk due to cardiovascular disease, chronic lower respiratory diseases, influenza and pneumonia, and kidney disease, but not with cancer or Alzheimer's disease.

Association between Diabetes and Cognitive Function among People over 45 Years Old in China: A Cross-Sectional Study

Objectives: The aim of this study is to identify the relationship between diabetes status including characteristics of diabetes and cognition among the middle-aged and elderly population (≥45 years) in China. Methods: A sample of 8535 people who participated in the China Health and Retirement Longitudinal Study (CHARLS) from June 2011 to March 2012 was analyzed. Two cognitive domains including episodic memory and executive function were measured through questionnaires. People were classified into four groups: no diabetes, controlled diabetes, untreated diabetes, treated but uncontrolled diabetes. Weighted multiple regression model was conducted to explore the association between diabetes and cognition in full sample as well as three different age groups (45–59, 60–74, ≥75). Adjustments were made for demographics and cardiovascular risk factors. Results: After adjusting several covariates, untreated diabetes (β = −0.192, p < 0.05) was significantly associated with episodic memory. In the age group of 45–69 years, untreated diabetes (β = −0.471, p < 0.05) and HbA1c level (β = −0.074, p < 0.05) were significantly associated with episodic memory. When adjusting for cardiovascular risk factors, all correlations were non-significant. Conclusion: The cross-sectional study suggests that untreated diabetes and HbA1c are the potential risk factor for cognitive impairment, and these associations are more significant in the age group of 45–59 years old. Cardiovascular factors are important mediating factors in the pathway between diabetes and cognitive impairment. More longitudinal studies are needed to confirm these associations.

Alzheimer's disease and type 2 diabetes mellitus are distinct diseases with potential overlapping metabolic dysfunction upstream of observed cognitive decline

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are highly prevalent aging-related diseases associated with significant morbidity and mortality. Some findings in human and animal models have linked T2DM to AD-type dementia. Despite epidemiological associations between the T2DM and cognitive impairment, the interrelational mechanisms are unclear. The preponderance of evidence in longitudinal studies with autopsy confirmation have indicated that vascular mechanisms, rather than classic AD-type pathologies, underlie the cognitive decline often seen in self-reported T2DM. T2DM is associated with cardiovascular and cerebrovascular disease (CVD), and is associated with increased risk of infarcts and small vessel disease in the brain and other organs. Neuropathological examinations of post-mortem brains demonstrated evidence of cerebrovascular disease and little to no correlation between T2DM and β-amyloid deposits or neurofibrillary tangles. Nevertheless, the mechanisms upstream of early AD-specific pathology remain obscure. In this regard, there may indeed be overlap between the pathologic mechanisms of T2DM/"metabolic syndrome," and AD. More specifically, cerebral insulin processing, glucose metabolism, mitochondrial function, and/or lipid metabolism could be altered in patients in early AD and directly influence symptomatology and/or neuropathology.

Risk Factors of Behavioral and Psychological Symptoms in Patients with Alzheimer Disease: The Clinical Research of Dementia of South Korea Study

Background

Few studies have evaluated risk factors for behavioral and psychological symptoms of dementia at the initial assessment for Alzheimer disease in large patient samples. In this study, the factors influencing Alzheimer disease were examined using the Clinical Research of Dementia of South Korea data.

Methods

This cross-sectional study was conducted using data of 1,128 patients with Alzheimer disease. The behavioral and psychological symptoms of dementia were examined using the Korean version of the Neuropsychiatric Inventory. Demographic characteristics, health-related behavior, neuropsychological tests, comorbidities, blood test results, and caregiver characteristics were assessed. Median logistic regression analysis with adjustment for covariates was conducted.

Results

The behavioral and psychological symptoms of dementia were negatively associated with memory (P=0.022) and frontal/executive (P<0.001) function in the Seoul Neuropsychological Screening Battery-dementia, Barthel Index for Activities of Daily Living (P<0.001), Korean version of the Mini-Mental State Examination score (P=0.003), and caregiver age (P=0.005) after adjustment for confounding factors, and positively associated with the Seoul-Instrumental Activities of Daily Living score (P<0.001), Clinical Dementia Rating Sum of Box (P<0.001), Global Deterioration Scale score (P<0.001), abnormality of free T4 level (P<0.001), anemia (P<0.001), and family history of stroke (P=0.001). Patients with female caregivers exhibited more severe behavioral and psychological symptoms of dementia than those with male caregivers.

Conclusion

Behavioral and psychological symptoms of dementia in Alzheimer disease patients were associated with various risk factors including the inability to live independently and Alzheimer disease severity. These findings suggest that prevention and treatment strategies for the behavioral and psychological symptoms of dementia should be comprehensive.

Type 2 Diabetes Mellitus and Alzheimer's Disease: Role of Insulin Signalling and Therapeutic Implications

In the last two decades, numerous in vitro studies demonstrated that insulin receptors and theirs downstream pathways are widely distributed throughout the brain. This evidence has proven that; at variance with previous believes; insulin/insulin-like-growth-factor (IGF) signalling plays a crucial role in the regulation of different central nervous system (CNS) tasks. The most important of these functions include: synaptic formation; neuronal plasticity; learning; memory; neuronal stem cell activation; neurite growth and repair. Therefore; dysfunction at different levels of insulin signalling and metabolism can contribute to the development of a number of brain disorders. Growing evidences demonstrate a close relationship between Type 2 Diabetes Mellitus (T2DM) and neurodegenerative disorders such as Alzheimer’s disease. They, in fact, share many pathophysiological characteristics comprising impaired insulin sensitivity, amyloid β accumulation, tau hyper-phosphorylation, brain vasculopathy, inflammation and oxidative stress. In this article, we will review the clinical and experimental evidences linking insulin resistance, T2DM and neurodegeneration, with the objective to specifically focus on insulin signalling-related mechanisms. We will also evaluate the pharmacological strategies targeting T2DM as potential therapeutic tools in patients with cognitive impairment.

Correlation between Diabetes Mellitus and Knee Osteoarthritis: A Dry-To-Wet Lab Approach

Recent years have witnessed an increased prevalence of knee osteoarthritis (KOA) among diabetes mellitus (DM) patients-conditions which might share common risk factors such as obesity and advanced aging. Therefore, we conducted dry-to-wet lab research approaches to assess the correlation of type 1 DM (T1DM) and type 2 DM (T2DM) with KOA among all age and genders of Taiwanese population. The strength of association (odds ratio: OR) was analyzed using a phenome-wide association study portal. Populations of 37,353 T1DM and 1,218,254 T2DM were included. We observed a significant association of KOA with T1DM (OR: 1.40 (1.33⁻1.47), p< 0.0001) and T2DM (OR: 2.75 (2.72⁻2.78), p< 0.0001). The association between T1DM and KOA among the obese (OR: 0.99 (0.54⁻1.67), p = 0.0477) was insignificant compared to the non-obese (OR: 1.40 (1.33⁻1.48), p < 0.0001). Interestingly, a higher association between T2DM and KOA among non-obese persons (OR: 2.75, (2.72⁻2.79), p < 0.0001) compared to the obese (OR: 1.71 (1.55⁻1.89), p < 0.0001) was noted. Further, histopathologic and Western blot studies of diabetic mice knee joints revealed enhanced carboxymethyl lysine (advanced glycation end product), matrix metalloproteinase-1, and reduced cartilage-specific proteins, including type II collagen (Col II), SOX9, and aggrecan (AGN), indicating deteriorated articular cartilage and proteoglycans. Results indicate that DM is strongly associated with KOA, and obesity may not be a confounding factor.

Antidiabetic and Neuroprotective Effect of the N-Butanol Extract of Fragaria nilgerrensis Schlecht. in STZ-Induced Diabetic Mice

Diabetes has been associated with neurodegenerative disorders that are accompanied by memory loss and cognitive impairments, but there is no effective treatment for it at present. Fragaria nilgerrensis Schlecht. (FNS), a well-known Chinese materia medica, has been traditionally used for the folkloric treatment of diabetes and other diseases. However, its effects are poorly documented. Here, we investigated the antidiabetic and neuroprotective effect of FNS in diabetic mice. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) evaluations of N-butanol extract of Fragaria nilgerrensis Schlecht. (N-FNS) showed the presence of flavonoid and its structure is similar to scutellarin. For the first time, we show the potential neuroprotective and antidiabetic effects of FNS. After 4 weeks of FNS intervention, a significant decrease in blood glucose, increase in body weight, and amelioration in glucose tolerance were observed in FNS treated diabetic mice. In the acute study, FNS enhanced motor activity in the open field task and significantly prevented spatial-learning deficits in Morris water maze tests. Besides, synapse ultrastructure of the hippocampus showed that the mitochondrial morphology was basically restored and all the synaptic structural parameters were gradually normalized after treatment with FNS. Importantly, we found that the activities of SOD and CAT in liver and hippocampus of diabetic mice significantly increased after FNS administration. In vitro, FNS and scutellarin showed high DPPH radical scavenging activity. The study suggests that FNS exerted significant antidiabetic and neuroprotective effects which may be attributed to its antioxidant property.

Chemical, biological and molecular modelling analyses to probe into the pharmacological potential of Antidesma madagascariense Lam.: A multifunctional agent for developing novel therapeutic formulations

Antidesma madagascariense Lam. (AM), an indigenous medicinal plant to the Mascarene Islands, is used for the treatment of several diseases. We endeavoured to validate its use via evaluating the kinetics of inhibition of crude aqueous extract (CAE) and crude methanol extract (CME) of AM against key metabolic enzymes (pancreatic lipase, cholesterol esterase [CEase], acetylcholinesterase [AChE], and urease). In vitro antiglycation, antioxidant, cytotoxicity using iCELLigence real time cell analysis system and WST-1 methods, were used. LC-ESI-MS/MS was employed to determine the phenolic composition of the extracts and interaction of selected compounds to the studied enzymes was determined using in silico docking. AChE was inhibited by the CME of AM and CEase by the CAE. Both extracts were active inhibitors of urease and pancreatic lipase. Hyperoside (271.97 μg/g extract), present in large amount in the CME, docked to the enzymatic pocket of urease and CEase. The extracts showed competitive and mixed inhibition of urease and pancreatic lipase, respectively. The antioxidant capacity of the CME (6.61 μg GAE/mg crude extract) was higher compared to CAE (2.20 μg GAE/mg crude extract). AM extracts were significantly (p <  0.05) less potent than aminoguanidine in preventing advanced glycation end products formation. Toxicological screening revealed that both extracts were non-toxic on HEK-293 cells. AM crude extracts at concentrations ranging from 78 to 312 μg/ml did not cause a visible change in cell morphology compared to control. This study supports the safe use of AM as a biomedicine for the management and/or treatment of common non-communicable diseases.

Nilvadipine in mild to moderate Alzheimer disease: A randomised controlled trial

BACKGROUND

This study reports the findings of the first large-scale Phase III investigator-driven clinical trial to slow the rate of cognitive decline in Alzheimer disease with a dihydropyridine (DHP) calcium channel blocker, nilvadipine. Nilvadipine, licensed to treat hypertension, reduces amyloid production, increases regional cerebral blood flow, and has demonstrated anti-inflammatory and anti-tau activity in preclinical studies, properties that could have disease-modifying effects for Alzheimer disease. We aimed to determine if nilvadipine was effective in slowing cognitive decline in subjects with mild to moderate Alzheimer disease.

METHODS AND FINDINGS

NILVAD was an 18-month, randomised, placebo-controlled, double-blind trial that randomised participants between 15 May 2013 and 13 April 2015. The study was conducted at 23 academic centres in nine European countries. Of 577 participants screened, 511 were eligible and were randomised (258 to placebo, 253 to nilvadipine). Participants took a trial treatment capsule once a day after breakfast for 78 weeks. Participants were aged >50 years, meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's disease Criteria (NINCDS-ADRDA) for diagnosis of probable Alzheimer disease, with a Standardised Mini-Mental State Examination (SMMSE) score of ≥12 and <27. Participants were randomly assigned to 8 mg sustained-release nilvadipine or matched placebo. The a priori defined primary outcome was progression on the Alzheimer's Disease Assessment Scale Cognitive Subscale-12 (ADAS-Cog 12) in the modified intention-to-treat (mITT) population (n = 498), with the Clinical Dementia Rating Scale sum of boxes (CDR-sb) as a gated co-primary outcome, eligible to be promoted to primary end point conditional on a significant effect on the ADAS-Cog 12. The analysis set had a mean age of 73 years and was 62% female. Baseline demographic and Alzheimer disease-specific characteristics were similar between treatment groups, with reported mean of 1.7 years since diagnosis and mean SMMSE of 20.4. The prespecified primary analyses failed to show any treatment benefit for nilvadipine on the co-primary outcome (p = 0.465). Decline from baseline in ADAS-Cog 12 on placebo was 0.79 (95% CI, -0.07-1.64) at 13 weeks, 6.41 (5.33-7.49) at 52 weeks, and 9.63 (8.33-10.93) at 78 weeks and on nilvadipine was 0.88 (0.02-1.74) at 13 weeks, 5.75 (4.66-6.85) at 52 weeks, and 9.41 (8.09-10.73) at 78 weeks. Exploratory analyses of the planned secondary outcomes showed no substantial effects, including on the CDR-sb or the Disability Assessment for Dementia. Nilvadipine appeared to be safe and well tolerated. Mortality was similar between groups (3 on nilvadipine, 4 on placebo); higher counts of adverse events (AEs) on nilvadipine (1,129 versus 1,030), and serious adverse events (SAEs; 146 versus 101), were observed. There were 14 withdrawals because of AEs. Major limitations of this study were that subjects had established dementia and the likelihood that non-Alzheimer subjects were included because of the lack of biomarker confirmation of the presence of brain amyloid.

CONCLUSIONS

The results do not suggest benefit of nilvadipine as a treatment in a population spanning mild to moderate Alzheimer disease.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02017340, EudraCT number 2012-002764-27.

Association between vascular comorbidity and progression of Alzheimer's disease: a two-year observational study in Norwegian memory clinics

Background

Vascular risk factors increase the risk of Alzheimer’s disease (AD), but there is limited evidence on whether comorbid vascular conditions and risk factors have an impact on disease progression. The aim of this study was to examine the association between vascular disease and vascular risk factors and progression of AD.

Methods

In a longitudinal observational study in three Norwegian memory clinics, 282 AD patients (mean age 73.3 years, 54% female) were followed for mean 24 (16–37) months. Vascular risk factors and vascular diseases were registered at baseline, and the vascular burden was estimated by the Framingham Stroke Risk Profile (FSRP). Cerebral medical resonance images (MRIs) were assessed for white matter hyperintensities (WMH), lacunar and cortical infarcts. The associations between vascular comorbidity and progression of dementia as measured by annual change in Clinical Dementia Rating Sum of Boxes (CDR-SB) scores were analysed by multiple regression analyses, adjusted for age and sex.

Results

Hypertension occurred in 83%, hypercholesterolemia in 53%, diabetes in 9%, 41% were overweight, and 10% were smokers. One third had a history of vascular disease; 16% had heart disease and 15% had experienced a cerebrovascular event. MRI showed lacunar infarcts in 16%, WMH with Fazekas score 2 in 26%, and Fazekas score 3 in 33%. Neither the vascular risk factors and diseases, the FSRP score, nor cerebrovascular disease was associated with disease progression in AD.

Conclusions

Although vascular risk factors and vascular diseases were prevalent, no impact on the progression of AD after 2 years was shown.

Bushen Huoxue Attenuates Diabetes-Induced Cognitive Impairment by Improvement of Cerebral Microcirculation: Involvement of RhoA/ROCK/moesin and Src Signaling Pathways

Type 2 Diabetes mellitus (T2DM) is closely correlated with cognitive impairment and neurodegenerative disease. Bushen Huoxue (BSHX) is a compound Chinese medicine used clinically to treat diabetes-induced cognitive impairment. However, its underlying mechanisms remain unclear. In the present study, KKAy mice, a genetic model of type 2 diabetes with obesity and insulin resistant hyperglycemia, received a daily administration of BSHX for 12 weeks. Blood glucose was measured every 4 weeks. After 12 weeks, BSHX treatment significantly ameliorated the T2DM related insults, including the increased blood glucose, the impaired spatial memory, decreased cerebral blood flow (CBF), occurrence of albumin leakage, leukocyte adhesion and opening capillary rarefaction. Meanwhile, the downregulation of the tight junction proteins (TJ) claudin-5, occludin, zonula occluden-1 (ZO-1) and JAM-1 between endothelial cells, amyloid-β (Aβ) accumulation in hippocampus, increased AGEs and RAGE, and expression of RhoA/ROCK/moesin signaling pathway and phosphorylation of Src kinase in KKAy mice were significantly protected by BSHX treatment. These results indicate that the protective effect of BSHX on T2DM-induced cognitive impairment involves regulation of RhoA/ROCK1/moesin signaling pathway and phosphorylation of Src kinase.

A Comparative Assessment of Biological Effects and Chemical Profile of Italian Asphodeline lutea Extracts

The present study aims to highlight the therapeutic potential of Asphodeline lutea (AL), a wild edible plant of the Mediterranean diet. Roots, aerial parts, and flowers of AL at two different phenological stages were collected from three locations in Italy. The inhibitory activities of extracts on strategic enzymes linked to human diseases were assessed. The antioxidant properties were evaluated in vitro, using six standard bioassays. The phenolic and anthraquinone profiles were also established using HPLC-PDA. Zinc, cadmium, lead, and copper contents were also determined. All the samples inhibited acetylcholinesterase (from 1.51 to 2.20 mg GALAEs/g extract), tyrosinase (from 7.50 to 25.3 mg KAEs/g extract), and α-amylase (from 0.37 to 0.51 mmol ACAEs/g extract). Aloe-emodin and physcion were present in all parts, while rhein was not detected. The phenolic profile and the heavy metals composition of specimens gathered from three different regions of Italy were different. It can be argued that samples collected near the street can contain higher concentrations of heavy metals. The experimental data confirm that the A. lutea species could be considered as a potential source of bioactive metabolites, and its consumption could play a positive and safe role in human health maintenance.

Alzheimer's Disease, Oligomers, and Inflammation

The production of soluble amyloid-β oligomers (AβOs) and the activation of inflammation are two important early steps in the pathogenesis of Alzheimer's disease (AD). The central role of oligomers as responsible for the neuronal dysfunction associated with the clinical features has been extended to the other protein misfolding disorders definable, on this basis, as oligomeropathies. In AD, recent evidence indicates that the mechanism of inflammation as a consequence of neurodegeneration must be assessed in favor of a more direct role of glial activation in the alteration of synaptic function. Our own experimental models demonstrate the efficacy of anti-inflammatory treatments in preventing the cognitive deficits induced acutely by AβOs applied directly in the brain. Moreover, some promising clinical tools are based on immunological activation reducing the presence of cerebral Aβ deposits. However, the strategies based on the control of inflammatory factors as well as the amyloid aggregation show poor or non-therapeutic efficacy. Numerous studies have examined inflammatory factors in biological fluids as possible markers of the neuroinflammation in AD. In some cases, altered levels of cytokines or other inflammatory markers in cerebrospinal fluid correlate with the severity of the disease. Here we propose, according to the precision medicine principles, innovative therapeutic approaches to AD based on the patient's inflammatory profile/state. The earlier intervention and a multifactor approach are two other elements considered essential to improve the chances of effective therapy in AD.

Metformin - a Future Therapy for Neurodegenerative Diseases : Theme: Drug Discovery, Development and Delivery in Alzheimer's Disease Guest Editor: Davide Brambilla

Type 2 diabetes mellitus (T2DM) is a complex, chronic and progressive metabolic disease, which is characterized by relative insulin deficiency, insulin resistance, and high glucose levels in blood. Esteemed published articles and epidemiological data exhibit an increased risk of developing Alzheimer's disease (AD) in diabetic pateints. Metformin is the most frequently used oral anti-diabetic drug, which apart from hypoglycaemic activity, improves serum lipid profiles, positively influences the process of haemostasis, and possesses anti-inflammatory properties. Recently, scientists have put their efforts in establishing metformin's role in the treatment of neurodegenerative diseases, such as AD, amnestic mild cognitive impairment and Parkinson's disease. Results of several clinical studies confirm that long term use of metformin in diabetic patients contributes to better cognitive function, compared to participants using other anti-diabetic drugs. The exact mechanism of metformin's advantageous activity in AD is not fully understood, but scientists claim that activation of AMPK-dependent pathways in human neural stem cells might be responsible for the neuroprotective activity of metformin. Metformin was also found to markedly decease Beta-secretase 1 (BACE1) protein expression and activity in cell culture models and in vivo, thereby reducing BACE1 cleavage products and the production of Aβ (β-amyloid). Furthermore, there is also some evidence that metformin decreases the activity of acetylcholinesterase (AChE), which is responsible for the degradation of acetylcholine (Ach), a neurotransmitter involved in the process of learning and memory. In regard to the beneficial effects of metformin, its anti-inflammatory and anti-oxidative properties cannot be omitted. Numerous in vitro and in vivo studies have confirmed that metformin ameliorates oxidative damage.

Longitudinal Cognitive Profiles in Diabetes: Results From the National Alzheimer's Coordinating Center's Uniform Data

BACKGROUND

Diabetes is a risk factor for the development of cognitive impairment and possibly for accelerated progression to Alzheimer disease (AD) and other dementias, though the trajectory of cognitive decline in general and in specfic cognitive domains by diabetes is unclear.

METHODS

Using the National Alzheimer's Coordinating Center's Uniform Data Det (NACC-UDS) to identify cohorts of elders with normal cognition (N = 7,663) and mild cognitive impairment (MCI, N = 4,114), we compared overall cognitive composite and domain specific sub-scores and their progression over time between diabetic and non-diabetic subjects.

RESULTS

Diabetes was more common among those with MCI (14.7%) than among subjects who were cognitively normal (11.7%). In subjects who were cognitively normal, baseline cognitive composite scores, attention, and executive function sub-scores were lower in diabetics than non-diabetics (by 0.098, 0.066, and 0.015 points, respectively). Over time, cognitive composite score showed subtle worsening in non-diabetics (0.025 points every 6 months), with an additional worsening of 0.01 points every 6 months in diabetics compared to non-diabetics. In the MCI groups, baseline cognitive composite as well as attention and executive domain sub-scores were lower in diabetics than non-diabetics (by 0.078, 0.092, and 0.032 points, respectively). Over time, cognitive composite (by 0.103 points every 6 months) and all domain specific sub-scores showed subtle worsening in non-diabetics, but diabetics had significantly slower worsening than non-diabetics on both cognitive composite (by 0.028 points) and domain specific sub-scores.

DISCUSSION

Among elders, diabetes may be associated with lower cognitive performance, primarily in non-memory domains. However it is not associated with continued worsening, suggesting a static deficit with minimal memory involvement. This data suggest that diabetes may contribute more to a vascular profile of cognitive impairment than a profile more typical of AD.