Associations between antipsychotics exposure and dementia risk: A prospective cohort study of 415,100 participants.

BACKGROUND: Antipsychotics (APs) are among the most widely prescribed medications, and have been shown to cause cognitive decline. But previous studies on their effects on dementia risk are controversial and scarce. We aimed to examine the relationships of APs exposure with the risk of dementia. METHODS: Data were obtained from a prospective cohort of 415,100 UK Biobank (UKB) participants. We investigated the effects of APs exposure and their various classes on dementia risk by using multivariable Cox proportional hazard models and further the dose-response effects of oral APs. RESULTS: After a mean follow-up of 8.64 years, 5235 (1.3 %) participants developed all-cause dementia (ACD), among whom 2313 (0.6 %) developed Alzheimer's disease (AD), and 1213 (0.3 %) developed vascular dementia (VaD). Exposure to any APs conferred increased risks of ACD (HR: 1.33, 95 % CI = 1.17-1.51, P < 0.001) and VaD (HR: 1.90, 95 % CI = 1.51-2.40, P < 0.001), but not AD (HR: 1.22, 95 % CI = 1.00-1.48, P = 0.051). Cumulative dose-response relationships of oral APs with the risks of ACD and VaD were observed (P for trend, P < 0.05). LIMITATIONS: Our study is observational and does not show evidence of causality. Since there are relatively few cases of dementia in the UKB, APs exposure may be higher than estimated in our study. CONCLUSIONS: APs exposure increased the risk of developing dementia. Dose-response relationships were found between oral APs and dementia risk. Efforts to raise awareness of doctors and patients about this potential drug-related risk are critical to reducing APs use.

Risk of Incident Atrial Fibrillation and Subsequent Use of Oral Anticoagulants in Patients with Dementia.

BACKGROUND: Dementia and atrial fibrillation (AF) have many shared risk factors. Besides, patients with dementia are under-represented in randomized trials, and even if AF is present, oral anticoagulants (OACs) are not prescribed frequently. This study aimed to report the incidence of newly diagnosed AF in dementia patients, and the impacts of use of vitamin K antagonist (VKA; e.g., warfarin) and non-VKA OAC (NOACs) on stroke and bleeding outcomes. METHODS: Our study utilized the Taiwan National Health Insurance Research Database. A total of 554,074 patients with dementia were compared with 554,074 age- and sex-matched patients without dementia regarding the risk of incident AF. Among patients with dementia who experienced incident AF, the risks of clinical events of patients treated with warfarin or NOACs were compared with those without OACs (reference group). RESULTS: The risk of incident AF was greater for patients with dementia compared with those without (adjusted hazard ratio [aHR]: 1.054; 95% confidence interval [CI]: 1.040-1.068 for all types of dementia, aHR: 1.035; 95% CI: 1.020-1.051 for presenile/senile dementia, and aHR: 1.125; 95% CI: 1.091-1.159 for vascular dementia). Among patients with dementia and experienced incident AF, warfarin use was associated with a higher risk of ischemic stroke (aHR: 1.290; 95% CI: 1.156-1.440), intracranial hemorrhage (ICH; aHR: 1.678; 95% CI: 1.346-2.090), and major bleeding (aHR: 1.192; 95% CI: 1.073-1.323) compared with non-OACs. NOAC use was associated with a lower risk of ischemic stroke (aHR: 0.421; 95% CI: 0.352-0.503) and composite risk of ischemic stroke or major bleeding (aHR: 0.544; 95% CI: 0.487-0.608) compared with non-OACs. These results were consistent among the patients after the propensity matching. CONCLUSION: In this large nationwide cohort, the risk of newly diagnosed AF was higher in patients with dementia (all dementia, presenile/senile dementia, and vascular dementia) compared with those without dementia. For patients with dementia who experienced incident AF, NOAC use was associated with a better clinical outcome compared with non-OAC. Patients with dementia require a holistic approach to their care and management, including the use of NOACs to reduce the risks of clinical events.

Direct oral anticoagulants are associated with lower risk of dementia in patients with atrial fibrillation.

BACKGROUND AND AIM: Atrial fibrillation (AF) is associated with increased risk of dementia. Whether direct oral anticoagulation (DOAC) reduce this risk compared to vitamin-K antagonist (VKA) is unclear. The aim of this study was to assess the risk of new all-cause dementia and vascular dementia in AF patients, treated with either DOAC or VKAs. METHODS: Anonymized electronic medical records from the TriNetX federated research network were used. AF patients treated with DOACs within 1 month of AF diagnosis, were 1:1 propensity score-matched with those treated with a VKA. The analysis included patients who completed 5 and 10 years of follow-up and were assessed for all-cause dementia and vascular dementia. Cox proportional hazard models were used to hazard ratios (HR), respectively with 95% confidence intervals (CIs). RESULTS: Among patients who completed 5 years of follow-up, after propensity score matching the final cohort consisted of 215,404 well-matched AF patients. All-cause dementia was diagnosed in 4,153 (3.9%) patients among those treated with DOACs and 4,150 (3.9%) among the VKA-treated patients (HR: 1.01, 95%CI: 0.96-1.05). Among patients 65-74 years old who were followed, DOAC treatment was associated with lower risk of dementia compared to VKAs (HR: 0.72; 95%CI: 0.59-0.86). Among patients who completed 10 years of follow-up, after propensity score matching the final cohort consisted of 19,208 well-matched AF patients. All-cause dementia was diagnosed in 314 (3.3%) patients among those treated with DOACs and 451 (4.7%) among the VKA-treated patients. DOAC treatment was associated with significantly lower risk of all-cause dementia during a follow-up period of 10 years compared to VKA treatment (HR: 0.72, 95%CI: 0.62-0.83), which remained consistent in patiens ≥65 years old. CONCLUSION: This propensity-score matched analysis showed that among AF patients, treatment with a DOACs for a period of 10 years was associated with lower risk of all-cause dementia and vascular dementia compared to VKA treatment, an effect which was not apparent in those treated for shorter duration. This finding requires confirmation in ongoing randomised controlled trials.

Association of regular use of ibuprofen and paracetamol, genetic susceptibility, and new-onset dementia in the older population.

OBJECTIVE: Although the possible efficacy and adverse effects of paracetamol and ibuprofen on dementia are of global clinical and public health importance, to date, the relationship of the use of paracetamol and ibuprofen with incident dementia remains uncertain. We aimed to assess the prospective association of regular use of ibuprofen and paracetamol with new-onset dementia in an older population. METHODS: This study included 212,968 participants from the UK Biobank, aged ≥60 years, with available data of ibuprofen, paracetamol use and without dementia at baseline. The primary outcome was new-onset all-cause dementia. The secondary outcomes included new-onset Alzheimer's disease and new-onset vascular dementia. RESULTS: During a median follow-up of 12.3 years, 6407 (3.0%) participants developed new-onset all-cause dementia. Participants who regularly used paracetamol had a significantly higher risk of new-onset all-cause dementia (adjusted HR, 1.18; 95%CI: 1.10-1.26), compared with non-users. However, there was no significant association between regular use of ibuprofen and new-onset all-cause dementia (users vs. non-users; adjusted HR, 1.06; 95%CI: 0.97-1.16). Furthermore, APOE ε4 dosage and genetic risk scores (GRS) of Alzheimer's disease calculated by 25 single nucleotide polymorphisms did not significantly modify the relationship of regular use of paracetamol and ibuprofen with new-onset all-cause dementia (Both P-interactions >0.05). Similar results were found in the propensity score analysis. Similar findings were also observed for new-onset Alzheimer's disease and new-onset vascular dementia. CONCLUSIONS: Regular use of paracetamol, but not ibuprofen, was associated with a significantly higher risk of new-onset dementia in the old population, regardless of genetic risks of dementia.

Acute pancreatitis during valproic acid administration in a patient with vascular dementia, epileptic seizures, and psychiatric symptoms: a case report.

BACKGROUND: Valproic acid (VPA) is a relatively safe drug widely used for the treatment of epileptic seizures and mania in bipolar disorder, as well as the prevention of migraine headaches. Here, we present a case of VPA-induced pancreatitis in a patient with vascular dementia, epileptic seizures, and psychiatric symptoms. He had no distinctive abdominal symptoms. CASE PRESENTATION: A 66-year-old Japanese man was treated with VPA for agitation and violent behavior due to vascular dementia, epileptic seizures, and psychiatric symptoms. During admission, he experienced a sudden decrease in consciousness and blood pressure. Abdominal findings were unremarkable; however, blood tests showed an inflammatory response and elevated amylase levels. Contrast-enhanced abdominal computed tomography showed diffuse pancreatic enlargement and inflammation extending to the subrenal pole. VPA-induced acute pancreatitis was diagnosed, VPA was discontinued, and high-dose infusions were administered. Acute pancreatitis resolved after treatment initiation. CONCLUSIONS: Clinicians should be aware of this relatively rare side effect of VPA. Diagnosis may be challenging in elderly people and patients with dementia as they may present with non-specific symptoms. Clinicians should consider the risk of acute pancreatitis when using VPA in patients who cannot report spontaneous symptoms. Blood amylase and other parameters should be measured accordingly.

Clinical implications of different types of dementia in patients with atrial fibrillation: Insights from a global federated health network analysis.

BACKGROUND: Atrial fibrillation (AF) associates with higher Alzheimer's disease (AD) and vascular dementia risks but the clinical implications have been scarcely investigated. We examined the association between AD or vascular dementia and adverse outcomes in AF patients. METHODS: Cohort study between January 2000 and 2017. AF patients were divided into two groups according to vascular dementia or AD, and balanced using propensity score matching (PSM). During 4-years of follow-up, incident intracranial hemorrhages (ICH), the composite of ischemic stroke/transient ischemic attack (TIA), hospitalizations, and all-cause deaths, were recorded. RESULTS: Two thousand three hundred seventy-seven AF patients with dementia (1225 with vascular dementia, and 1152 with AD) were identified. Following a PSM, 615 patients were included in each cohort (i.e., 1:1) and all variables were well-matched. After PSM, 22 (3.6%) patients with vascular dementia and 55 (8.1%) patients with AD had incident ICH during follow-up (hazard ratio [HR]: 2.22, 95% confidence interval [CI]: 1.33-3.70, log-rank p = 0.002). Overall, 237 (38.5%) patients with vascular dementia and 193 (31.4%) patients with AD, developed an ischemic stroke/TIA. The risk of ischemic stroke/TIA was 1.32-fold higher in vascular dementia (HR: 1.32, 95% CI: 1.09-1.59, log-rank p = 0.003). The risk of rehospitalization (HR: 1.14, 95% CI: 1.01-1.31), and mortality (HR: 1.25, 95% CI: 1.01-1.58) were also higher among AF patients with vascular dementia compared to AD. CONCLUSIONS: The two forms of dementia in AF patients are associated with different prognosis, with AD being associated with a higher risk of ICH, and vascular dementia with a higher risk of stroke/TIA, hospitalization, and mortality.

Collocation of metformin and dipeptidyl peptidase-4 inhibitor is associated with increased risk of diabetes-related vascular dementia: A single hospital study in Northern Taiwan.

BACKGROUND: Recent studies have established a close link between diabetes mellitus (DM) and an increased risk of vascular dementia (VD). In this study, we evaluated the risk of VD in patients with type 2 diabetes who were on antidiabetic medications. METHODS: There is a growing interest in observational and data-driven studies to answer specific research questions for defined populations. In line with this, 67,281 patients (age range, 61.95 ± 13.88 years; length of follow up, 3.2 ± 3.4 years) diagnosed with DM were divided into two groups:48,072 subjects who had not used dipeptidyl peptidase-4 (DPP-4) medication and 19,209 subjects who had taken DPP-4 medication. Each patient underwent follow-up examination after the date of the latest diagnosis. RESULTS: Among 10,884 DM patients with dementia, the combination therapy of metformin and DPP-4 inhibitor may increase the risk of dementia compared with that in the control group (adjusted hazard ratio, 1.11; 95% confidence interval, 1.06-1.15; p ≤ 0.001). CONCLUSION: In this study, patients who received a combination therapy of metformin and DPP-4 inhibitor for DM were at a higher risk of dementia than those who received monotherapy.

Association of 5α-Reductase Inhibitors With Dementia, Depression, and Suicide.

Importance: In recent decades, there has been increased interest in the possible adverse neurological effects of 5α-reductase inhibitors (5-ARIs), which have been used mainly for benign prostatic hyperplasia and androgenic alopecia. Numerous studies and reports have indicated associations of 5-ARIs with depression and suicide. However, most of these studies had methodological shortcomings, and very little is known about the potential association of 5-ARIs with dementia. Objective: To investigate the association of 5-ARI use with all-cause dementia, Alzheimer disease, vascular dementia, depression, and suicide. Design, Setting, and Participants: This Swedish register-based cohort study included 2 236 876 men aged 50 to 90 years between July 1, 2005, and December 31, 2018. Statistical analyses were performed from September 15, 2021, to May 25, 2022. Main Outcomes and Measures: A diagnosis of all-cause dementia, Alzheimer disease, vascular dementia, depression, or completed suicide. Exposures: A recorded prescription in the Swedish national prescription register of finasteride or dutasteride and duration of use. Results: Of 2 236 876 men (median age at the start of follow-up, 55 years [IQR, 50-65 years] and at treatment initiation, 73 years [IQR, 66-80 years]), 70 645 (3.2%) started finasteride treatment, and 8774 (0.4%) started dutasteride treatment. Men taking finasteride or dutasteride were at increased risk of all-cause dementia (finasteride: hazard ratio [HR], 1.22 [95% CI, 1.17-1.28]; dutasteride: HR, 1.10 [95% CI, 1.01-1.20]), Alzheimer disease (finasteride: HR, 1.20 [95% CI, 1.10-1.31]; dutasteride: HR, 1.28 [95% CI, 1.09-1.50]), vascular dementia (finasteride: HR, 1.44 [95% CI, 1.30-1.58]; dutasteride: HR, 1.31 [95% CI, 1.08-1.59]), and depression (finasteride: HR, 1.61 [95% CI, 1.48-1.75]; dutasteride: HR, 1.68 [95% CI, 1.43-1.96]). However, the magnitude of the association decreased over time, and the findings became statistically nonsignificant with continuous exposures over 4 years, except for depression, which showed a constant risk over time, with no differences between finasteride and dutasteride. In contrast, 5-ARIs were not associated with suicide (finasteride: HR, 1.22 [95% CI, 0.99-1.49]; dutasteride: HR, 0.98 [95% CI, 0.62-1.54]). Conclusions and Relevance: This cohort study found that, while men receiving 5-ARI treatment showed a higher risk for dementia in the initial periods after starting treatment, the decreasing magnitude of the association over time suggested that the risk may be, entirely or in part, due to increased dementia detection among patients with benign prostate enlargement. Both finasteride and dutasteride were similarly associated with depression with a constant risk over time, while neither drug was associated with suicide. Prescribing clinicians and potential users should be aware of the possible risks for depression associated with 5-ARI use.

Ambient air pollution and risk of incident dementia in older men living in a region with relatively low concentrations of pollutants: The Health in Men Study.

BACKGROUND: In areas with moderate to severe air pollution, pollutant concentrations are associated with dementia risk. It is unclear whether the same relationship is present in regions with lower ambient air pollution. OBJECTIVE: To determine whether exposure to air pollution is associated with risk of incident dementia in general, and Alzheimer's disease and vascular dementia in particular, in older men living in a relatively low ambient air pollution region. METHODS: The cohort comprised 11,243 men residing in Perth, Australia. Participants were aged ≥65 years and free of a dementia diagnosis at time of recruitment in 1996-1999. Incident dementia was identified from recruitment to 2018 via ICD diagnosis codes and subsequent study waves. Concentrations for three air pollutants, nitrogen dioxide (NO2), fine particulate matter less than 2.5 µm in diameter (PM2.5), and black carbon (BC) were estimated at participants' home addresses using land-use regression models. We used Cox proportional hazards regression models adjusting for smoking status, physical activity, BMI, education, and socio-economic status. RESULTS: Of 3053 (27.2%) incident cases of dementia, 1670 (54.7%) and 355 (11.6%) had documented Alzheimer's disease and vascular dementia. The average concentration of NO2 was 13.5 (SD 4.4) µg/m3, of PM2.5 was 4.54 (SD 1.6) µg/m3 and of BC was 0.97 (SD 0.29) ×10-5 m-1. None of the air pollutants were associated with incident dementia or Alzheimer's disease. In the unadjusted model, increased exposure to PM2.5 was associated with an increased risk of vascular dementia (for a 5 µg/m3 increase: HR 1.62, 95% CI 1.13, 2.31). However, this association was attenuated following adjustment for confounders (HR 1.39, 95% CI 0.93, 2.08). NO2 and BC were not associated with vascular dementia incidence. DISCUSSION: Exposure to air pollution is not associated with increased risk of incident dementia in older men living in a region with relatively low ambient air pollution.

Sitagliptin Attenuates the Cognitive Deficits in L-Methionine-Induced Vascular Dementia in Rats.

Vascular dementia (VaD) is the second most prevalent type of dementia characterized by progressive cognitive deficits and is a major risk factor for the development of Alzheimer's disease and other neurodegenerative disorders. This study is aimed at determining the potential neuroprotective effect of sitagliptin (STG) on cognitive deficits in L-methionine-induced VaD in rats and the possible underlying mechanisms. 30 adult male Wistar albino rats were divided equally (n = 10) into three groups: control, VaD, and VaD + STG groups. The cognitive performance of the animals was conducted by open field, elevated plus maze, Y-maze, novel object recognition, and Morris water maze tests. Serum homocysteine, TNF-α, IL-6, IL-10, total cholesterol, and triglycerides levels were assessed together with hippocampal MDA, SOD, and BDNF. Histopathological and immunohistochemical assessments of the thoracic aorta and hippocampus (CA1 region) were also performed. Chronic L-methionine administration impaired memory and learning and induced anxiety. On the other hand, STG protected against cognitive deficits through improving oxidative stress biomarkers, inflammatory mediators, lipid profiles, and hippocampus level of BDNF as well as decreasing caspase-3 and GFAP and increasing Ki-67 immunoreactions in the hippocampus. Also, STG improved the endothelial dysfunction via upregulation of aortic eNOS immunoreaction. STG improved the cognitive deficits of L-methionine-induced VaD by its antioxidant, anti-inflammatory, antiapoptotic, and neurotrophic effects. These findings suggest that STG may be a promising future agent for protection against VaD.

Ameliorative role of rolipram, PDE-4 inhibitor, against sodium arsenite-induced vascular dementia in rats.

Arsenic exposure to the population leads to serious health problems like neurotoxicity, nephrotoxicity, and cardiovascular abnormality. In the present study, the work has been commenced to discover the prospect of rolipram a phosphodiestrase-4 (PDE-4) inhibitor against sodium arsenite (SA)-induced vascular endothelial dysfunction (EnDF) leading to dementia in rats. Wistar rats were treated with SA (5 mg/kg body weight/day orally) for 44 days for induction of vascular EnDF and dementia. Learning and memory were evaluated using Morris water maze (MWM) test. Vascular EnDF was evaluated using aortic ring preparation. Various biochemical parameters were also evaluated like brain oxidative stress (viz. reduced glutathione and thiobarbituric acid reactive substances level), serum nitrite/nitrate activity, acetylcholinesterase activity, and inflammatory markers (viz. neutrophil infiltration in brain and myeloperoxidase). SA-treated rats showed poor performance in water maze trials indicating attenuated memory and ability to learn with significant rise (p < 0.05) in brain acetylcholinesterase activity, brain oxidative stress, neutrophil count, and significant decrease (p < 0.05) in serum nitrite/nitrate levels and vascular endothelial functions. Rolipram (PDE-4 inhibitor) treatment (0.03 mg/kg and 0.06 mg/kg body weight, intraperitoneally daily for 14 days) significantly improved memory and learning abilities, and restored various biochemical parameters and EnDF. It is concluded that PDE-4 modulator may be considered the prospective target for the treatment of SA-induced vascular EnDF and related dementia.

Carnosine as a Possible Drug for Zinc-Induced Neurotoxicity and Vascular Dementia.

Increasing evidence suggests that the metal homeostasis is involved in the pathogenesis of various neurodegenerative diseases including senile type of dementia such as Alzheimer's disease, dementia with Lewy bodies, and vascular dementia. In particular, synaptic Zn2+ is known to play critical roles in the pathogenesis of vascular dementia. In this article, we review the molecular pathways of Zn2+-induced neurotoxicity based on our and numerous other findings, and demonstrated the implications of the energy production pathway, the disruption of calcium homeostasis, the production of reactive oxygen species (ROS), the endoplasmic reticulum (ER)-stress pathway, and the stress-activated protein kinases/c-Jun amino-terminal kinases (SAPK/JNK) pathway. Furthermore, we have searched for substances that protect neurons from Zn2+-induced neurotoxicity among various agricultural products and determined carnosine (ß-alanyl histidine) as a possible therapeutic agent for vascular dementia.

Beta-blocker therapy and risk of vascular dementia: A population-based prospective study.

There are a few studies that report cognitive impairment as a complication of treatment with beta- blockers. We aimed to evaluate the longitudinal association between use of beta-blockers, as a class, and incident risk of all-cause dementia, vascular dementia, Alzheimer's and mixed dementia in the prospective population-based Malmö Preventive Project. We included 18,063 individuals (mean age 68.2, males 63.4%) followed up for 84,506 person-years. Dementia cases were retrieved from the Swedish National Patient Register and validated by review of medical records and neuroimaging data. We performed propensity score matching analysis, resulting in 3720 matched pairs of beta-blocker users and non-users at baseline, and multivariable Cox proportional-hazards regression. Overall, 122 study participants (1.6%) were diagnosed with dementia during the follow-up. Beta-blocker therapy was independently associated with increased risk of developing vascular dementia, regardless of confounding factors (HR: 1.72, 95%CI 1.01-3.78; p = .048). Conversely, treatment with beta-blockers was not associated with increased risk of all-cause, Alzheimer's and mixed dementia (HR:1.15; 95%CI 0.80-1.66; p = .44; HR:0.85; 95%CI 0.48-1.54; P = .59 and HR:1.35; 95%CI 0.56-3.27; p = .50, respectively). We observed that use of beta-blockers, as a class, is associated with increased longitudinal risk of vascular dementia in the general elderly population, regardless of cardiovascular risk factors, prevalent or incident history of atrial fibrillation, stroke, coronary events and heart failure. Further studies are needed to confirm our findings in the general population and to explore the mechanisms underlying the relationship between use of beta- blockers and increased risk of vascular dementia.

Glycyrrhizic acid renders robust neuroprotection in rodent model of vascular dementia by controlling oxidative stress and curtailing cytochrome-c release.

Background: Chronic cerebral hypoperfusion (CCH), a concern for neurocognitive health, is linked to various vascular ailments and other comorbidities. This study primarily aims to explain the mitigating effects of glycyrrhizic acid (GA) on cognitive health challenged by chronic cerebral hypoperfusion. Methods: Adult male Sprague Dawley rats were allocated into four groups: (i) Sham, (ii) Lesion (2VO), (iii) GA treated (20 mg/kg), and (iv) lithium chloride (Li) treated (40 mg/kg). On 30th postoperative day the rats were tested for cognitive behaviour through a repertoire of tests. Rats were transcardially perfused and the brain samples were obtained for histological assessments. For biochemical assessments, hippocampus isolated from fresh brain was utilized. Results: The antioxidant propensity of GA curtailed ROS generation by restoring mitochondrial complex I and IV, enzymatic and non-enzymatic antioxidant activity. However, Li group exhibited significantly reduced antioxidant defence, when compared with GA. The strong antioxidant defence had caused considerable restoration of pyramidal neurons, myelin and dendritic spine density in GA treated than Li treated. GA treated rats showed a remarkable amelioration of cognitive deficits when compared with lesion rats. Finally, GA also reduced the cytochrome-c release, thus creating a blockade for further succession of apoptotic events. Conclusion: The outcome of this study clearly implies that GA shows promising neuroprotection in CCH-induced rats by enhancing the endogenous antioxidants and curtails the apoptosis by reducing cytochrome-c release. GA was also found to be much better than Li through modulation of GSK3ß/Nrf2 pathway, in turn, mitigates the adverse consequences of CCH.

Association between air pollution and risk of vascular dementia: A multipollutant analysis in Taiwan.

Evidence regarding the association of specific air pollutants with vascular dementia (VaD) risk is limited. In this nested case-control study, we enrolled 831 adults aged >65 years with VaD (International Classification of Diseases, Ninth Revision, Clinical Modification code 290.4x) newly diagnosed during 2005-2013; 3324 controls were age-, sex-, and VaD diagnosis year-matched with the study patients. Both patients with VaD and controls were selected from among a cohort of one million beneficiaries of Taiwan's National Health Insurance program, all of whom were registered in 2005. Exposure to the mean daily air pollutant concentration, derived from 76 fixed air quality monitoring stations, in 3, 5, and 7 years before VaD diagnosis was assessed using the spatial analysis method (i.e., ordinary kriging) on ArcGIS. A logistic regression model was used to calculate covariate-adjusted odds ratios (ORs) of VaD in relation to specific air pollutants. After potential confounders and other air pollutants were controlled for, high concentrations of coarse particulate matter (10 µm or less in diameter) and carbon monoxide (CO) were sporadically associated with higher OR of VaD. The most prominent association was observed for nitrogen dioxide (NO2) exposure within 5 and 7 years before diagnosis. Compared with the <25th percentile of NO2 exposure, the 25th-50th, 50th-75th, and >75th percentiles of NO2 exposure significantly increased ORs (95% confidence intervals): 1.62 (1.28-2.23), 1.61 (1.11-2.33), and 2.22 (1.35-3.65) within 5 years before diagnosis, respectively, and 1.59 (1.20-2.11), 1.65 (1.15-2.37), and 2.05 (1.28-3.28) within 7 years before diagnosis, respectively. We found that higher NO2 exposure in the past was significantly associated with an elevated risk of VaD. Although less consistent, higher exposure to CO was also associated with a higher risk of VaD. Most NO2 in cities originates from motor vehicle exhaust; other sources of NO2 are petrol and metal refining, electricity generation from coal-fired power stations, other manufacturing industries, and food processing. Future studies should investigate associations of VaD with specific sources of NO2.

Distinct Impacts of Fullerene on Cognitive Functions of Dementia vs. Non-dementia Mice.

Fullerene is a family of carbon materials widely applied in modern medicine and ecosystem de-contamination. Its wide application makes human bodies more and more constantly exposed to fullerene particles. Since fullerene particles are able to cross the blood-brain barrier (BBB) (Yamago et al. 1995), if and how fullerene would affect brain functions need to be investigated for human health consideration. For this purpose, we administered fullerene on subcortical ischemic vascular dementia (SIVD) model mice and sham mice, two types of mice with distinct penetration properties of BBB and hence possibly distinct vulnerabilities to fullerene. We studied the spatial learning and memory abilities of mice with Morris water maze (MWM) and the neuroplasticity properties of the hippocampus. Results showed that fullerene administration suppressed outcomes of MWM in sham mice, along with suppressed long-term potentiation (LTP) and dendritic spine densities. Oppositely, recoveries of MWM outcomes and neuroplasticity properties were observed in fullerene-treated SIVD mice. To further clarify the mechanism of the impact of fullerene on neuroplasticity, we measured the levels of postsynaptic density protein 95 (PSD-95), synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), and tropomyosin receptor kinase B (TrkB) by western blot assay. Results suggest that the distinct impacts of fullerene on behavior test and neuroplasticity may be conducted through postsynaptic regulations that were mediated by BDNF.

Proton Pump Inhibitor Use and Risk of Developing Alzheimer's Disease or Vascular Dementia: A Case-Control Analysis.

INTRODUCTION: Long-term use of proton pump inhibitors (PPIs) has been associated with an increased risk of Alzheimer's disease (AD) in observational studies. The role of exposure duration, and whether this applies to other dementia subtypes, has not been explored in these studies. OBJECTIVE: The aim was to study the association between long-term use of PPIs (or of histamine-2 receptor antagonists [H2RAs], as a negative control) and the risk of developing AD or vascular dementia (VaD). METHODS: We conducted a case-control analysis on the UK-based Clinical Practice Research Datalink (CPRD). We identified 41,029 patients aged ≥ 65 years with newly diagnosed AD or VaD between 1998 and 2015 and matched them 1:1 to dementia-free controls on age, sex, calendar time, general practice, and number of years of recorded history. We applied conditional logistic regression analyses to calculate adjusted odds ratios (aORs), with 95% confidence intervals (CIs), of developing AD or VaD in relation to previous use of PPIs or H2RAs, categorized by exposure duration. RESULTS: As compared to non-use, long-term PPI use (≥ 100 prescriptions) was not associated with an increased risk of developing AD (aOR 0.88, 95% CI 0.80-0.97) or VaD (aOR 1.18, 95% CI 1.04-1.33). Neither was long-term use of H2RAs (≥ 20 prescriptions) associated with an increased risk of developing AD (aOR 0.94, 95% CI 0.87-1.02) or VaD (aOR 0.99, 95% CI 0.89-1.10). CONCLUSION: In this large, case-control analysis, we did not find any evidence for an increased risk of either AD or VaD related to PPI or H2RA use.

Vitamin B6 prevents isocarbophos-induced vascular dementia in rats through N-methyl-D-aspartate receptor signaling.

BACKGROUND: We have previously reported that the long-term exposure of organophosphorus induces vascular dementia (VD) in rats. As a coenzyme, vitamin B6 is mainly involved in the regulation of metabolisms. Whether vitamin B6 improves VD remains unknown. METHODS: The model of VD was induced by feeding rats with isocarbophos (0.5 mg/kg per two day, 12 weeks). The blood flow of the posterior cerebral artery (PCA) in rat was assessed by transcranial Doppler (TCD). The learning and memory were evaluated by the Morris Water Maze (MWM) test. RESULTS: Administration of vitamin B6 increased the blood flow in the right and left posterior cerebral arteries and improved the functions of learning and memory in isocarbophos-treated rats. Vitamin B6 increased the protein levels of N-methyl-D-aspartate receptor (NMDAR) 2B, postsynaptic densities (PSDs) protein 95, and calmodulin-dependent protein kinase II (CaMK-II) in the hippocampus, which were decreased by isocarbophos in rats. Morphological analysis by light microscope and electronic microscope indicated disruptions of the hippocampus caused by isocarbophos were normalized by vitamin B6. Importantly, the antagonist of NMDAR signaling by eliprodil abolished these beneficial effects produced by vitamin B6 on PCA blood flow, learning, memory, and hippocampus structure in rats, as well as the protein expression of NMDAR 2B, PSDs protein 95, and CaMK-II in the hippocampus. CONCLUSION: Vitamin B6 activates NMDAR signaling to prevent isocarbophos-induced VD in rats.

Possible role of endothelin receptor against hyperhomocysteinemia and ß-amyloid induced AD type of vascular dementia in rats.

Vascular dementia (VaD) is considered as the second commonest form of dementia after Alzheimer's disease (AD). The study was designed to investigate the effect of endothelin receptor against ß-amyloid induced AD type of vascular dementia. This disease was induced by combine administration of single ICV (intracerebroventricle) infusion of ß-amyloid (Aß) once and chronic oral administration of l-Methionine for 21 days. Bosentan (dual endothelin receptor antagonist) was administered for 21 days. Behavioral alterations were observed during different time interval of the study. Animals were killed immediately following the last behavior session. Oxidative parameters, acetylcholinesterase activity, neuro-inflammatory markers, amyloid beta levels were determined in hippocampus and cortex while serum homocysteine, serum nitrite carotid artery superoxide anion level were also determined. Endothelial function was measured on isolated carotid artery using myograph instrument. Aß+l-Methionine showed more significant development of cognitive and vascular endothelial deficits, manifested in terms of increase in serum homocysteine level, endothelial dysfunction, impairment of learning and memory, enhanced brain acetylcholinesterase activity, marked mito-oxidative damage in rats. We have observed that l-Methionine and combination of Aß+l-Methionine significantly enhanced Aß level both in cortex as well as hippocampus. Treatment of bosentan attenuated Aß+l-Methionine induced impairment of learning and memory, enhanced Aß level, mitochondrial and endothelial dysfunction. The results of present study concluded that bosentan offers protection against ß-amyloid-induced vascular dementia in rats. Endothelin receptor may be considered as a potential pharmacological target for the management of AD type of vascular dementia.

Neuroprotective Effects of Simvastatin and Cilostazol in L-Methionine-Induced Vascular Dementia in Rats.

Vascular dementia (VaD) is a degenerative cerebrovascular disorder that leads to progressive decline in cognitive abilities and memory. Several reports demonstrated that oxidative stress and endothelial dysfunction are principal pathogenic factors in VaD. The present study was constructed to determine the possible neuroprotective effects of simvastatin in comparison with cilostazol in VaD induced by L-methionine in rats. Male Wistar rats were divided into four groups. Group I (control group), group II received L-methionine (1.7 g/kg, p.o.) for 32 days. The remaining two groups received simvastatin (50 mg/kg, p.o.) and cilostazol (100 mg/kg, p.o.), respectively, for 32 days after induction of VaD by L-methionine. Subsequently, rats were tested for cognitive performance using Morris water maze test then sacrificed for biochemical and histopathological assays. L-methionine induced VaD reflected by alterations in rats' behavior as well as the estimated neurotransmitters, acetylcholinesterase activity as well as increased brain oxidative stress and inflammation parallel to histopathological changes in brain tissue. Treatment of rats with simvastatin ameliorated L-methionine-induced behavioral, neurochemical, and histological changes in a manner comparable to cilostazol. Simvastatin may be regarded as a potential therapeutic strategy for the treatment of VaD. To the best of our knowledge, this is the first study to reveal the neuroprotective effects of simvastatin or cilostazol in L-methionine-induced VaD. Graphical Abstract ᅟ.