Vascular and Nonvascular Mechanisms of Cognitive Impairment and Dementia

A Longitudinal Study of the Relationship Among Cognition, Mood Symptoms, and Markers of Brain Health in Older Age Bipolar Disorder: Une étude longitudinale de la relation entre la cognition, les symptômes thymiques, et les marqueurs de la santé du cerveau en présence de troubles bipolaires du sujet âgé

ObjectivesAn emerging literature has assessed cognition or imaging markers of brain health in in older age bipolar disorder (OABD). In this context, we conducted the first longitudinal study (to our knowledge) that assessed the relationship among cognition, mood symptoms, and imaging markers of brain health in OABD.Methods99 participants with OABD were enrolled, underwent baseline assessment, and were followed annually for up to 3 years. They completed comprehensive assessments that included evaluation of general medical status, vascular disease burden, mental status, cognitive performance. A subset of participants (n = 58) completed magnetic resonance imaging (MRI) at one or two time-points, yielding three measures of brain health: gray matter volume, fractional anisotropy (FA), and burden of white matter hyperintensities (WMH).ResultsGroup-based trajectory modelling (GBTM) of overall cognitive performance revealed two groups: a group with higher cognitive performance (63 of 99, 63.6%) and a group with lower cognitive performance (36 of 99, 36.4%). GBTM also revealed two groups based on each of the three imaging markers of brain health. The higher cognitive performance group was associated with the groups with higher measure of total gray matter or higher FA. We found no relationship between the cognitive groups and level of mood symptoms during longitudinal follow-up or WMH burden.ConclusionsIn this first longitudinal study of cognition, mood symptoms, and markers of brain health in OABD, cognitive performance was related to brain health and not to mood symptoms over a follow-up of up to three years. Almost two-thirds of participants with OABD had cognitive performance comparable to older adults without OABD. Larger future studies will need to replicate and extend these findings.

Analysis of the Prevalence of Mild Cognitive Impairment and its Influencing Factors in the Elderly Population in Huzhou City

BACKGROUND

Mild cognitive impairment (MCI) is a critical stage in the development of Alzheimer's disease, and early intervention in patients during this stage may reverse or delay their disease progression. As one of the regions with severe aging in China, it is necessary to understand the prevalence of MCI in Huzhou and adopt effective intervention measures. The study was aimed to investigate the prevalence rate and influencing factors of MCI in the elderly population in Huzhou city.

METHODS

A cross-sectional study was conducted involving 800 elderly residents of Huzhou city. The Montreal Cognitive Assessment (MoCA) and the activity of daily living (ADL) were used to assess the occurrence of MCI in the elderly. The influencing factors of MCI were investigated by univariate analysis and multi-factor analysis.

RESULTS

A total of 800 questionnaires were sent out in this survey, and 778 were effectively collected, with an effective recovery rate of 97.25%. Among 778 elderly people in Huzhou city, 668 had normal cognitive function, 82 had MCI, and 28 had dementia, the prevalence rate of MCI was 10.54% (82/778). According to the presence or absence of MCI, the patients were divided into an MCI group (n = 82) and a non-MCI group (n = 668). Female (p = 0.026), high age (p = 0.009), low Community Screening Instrument for Dementia (CSI-D) score (p = 0.007), high Dementia Screening Questionnaire (AD8) score (p < 0.001), high Patient Health Questionnaire Depression Scale (PHQ-9) score (p = 0.037) were all risk factors for MCI in the urban elderly population of Huzhou City.

CONCLUSION

The prevalence of MCI in the elderly population in Huzhou City is high, and its occurrence is closely related to many factors. It is necessary to increase attention to the high-risk population of MCI and implement targeted intervention measures to improve their cognitive function and improve the quality of life of the elderly population.

Effects of repetitive transcranial magnetic stimulation on learning and memory cognitive function in rats with vascular cognitive impairment and its neural induction mechanism

BACKGROUND

The treatment of vascular cognitive impairment (VCI) is challenging, and its neurological mechanisms are not yet fully understood. Repetitive transcranial magnetic stimulation (rTMS) offers a new non-invasive treatment approach.

METHODS

One hundred male SD rats were grouped: intervention group (IG), model group (MG), sham group (SG), and control group (CG), to prepare the rat model of VCI. The Morris water maze (MWM) test was conducted, and oxidative stress (OS) markers, neurotrophic factors, apoptosis factors, and the amplitude of postsynaptic potential (PSP) in the hippocampus of rats were measured.

RESULTS

Post-intervention, IG's escape latency was lower than MG but higher than SG and CG. IG's hippocampal malondialdehyde (MDA) content, Bax, and Caspase-3 (Cas-3) were lower than MG but higher than SG and CG, while the tendency was opposite for Bcl-2 expression and the content of glutathione (GSH) and superoxide dismutase (SOD). IG's brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and N-methyl-D-aspartate receptor 1 (NMDAR1) in the hippocampus were higher than MG but lower than SG and CG; The changes in the amplitude of PSP in the hippocampal region of IG at 10, 30, and 60 min were all higher than those in MG but lower than those in SG and CG (P < 0.05).

CONCLUSION

Low-frequency rTMS visibly improved the learning and memory abilities of VCI rats and reduced OS levels.

Diagnosis and Management of Dementia for the Nephrology Clinician: A Review

Dementia describes when a person has cognitive limitations that impede function. Persons with kidney disease are unduly impacted by dementia: up to 87% of the dialysis population has cognitive impairment. In this review, we discuss the diagnosis and management of dementia, including the role of cerebrovascular disease and other risk factors. We review the available screening tools for the diagnosis of dementia. We discuss how the diagnosis of dementia differs from the diagnosis of mild cognitive impairment and also detail how delirium and depression can mimic dementia. In terms of treatments for dementia, we highlight 4 components. First, we describe pharmacologic treatments for the management of dementia, including the cholinesterase inhibitors N-methyl-d-aspartate antagonists as well as the newer antiamyloid antibody drugs for Alzheimer dementia. Second, we discuss the importance of nonpharmacologic interventions for the management of dementia, especially exercise. Third, we review approaches for the behavioral and neuropsychiatric symptoms associated with dementia, including potential medication management. Fourth, we highlight the essential and valuable role of caregivers in both the diagnosis and management of dementia. We conclude with key considerations about the impact of dementia for persons receiving dialysis and the role of dementia in kidney transplant evaluation.

Research hotspots and trends in the antioxidant effects of acupuncture: A bibliometric analysis from 2003 to 2024

OBJECTIVE

Oxidative stress is an important factor mediating the pathologic progression of many diseases. In recent years, the antioxidant effects of acupuncture have been gradually confirmed. However, bibliometric analysis in this field, which is still lacking. This study aimed to explore the current state of research and recent trends in the regulating of oxidative stress by acupuncture using bibliometric methods.

METHODS

Articles pertaining to the acupuncture antioxidant effects were systematically retrieved from the Web of Science Core Collection database, encompassing the temporal scope from inception to September 6, 2024. Countries, publications, authors, co-citations, and keywords were visualized and analyzed using CiteSpace, VOSviewer, and R software.

RESULTS

A total of 438 articles have been published in the field, with the number increasing yearly. Chinese scholars constitute a significant force in the domain of research pertaining to this field. Beijing University of Traditional Chinese Medicine is the institution with the highest number of publications. Cunzhi Liu (17) is the author with the highest number of publications. The journals with the most publications (39) and citations (652) are EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE. Basic research is the main type of research. Both co-cited literature analysis and keyword examination have indicated neurological disorders, including Alzheimer's disease, Parkinson's disease, and stroke, as prominent research domains. Electroacupuncture is the most common intervention. Pain and inflammation may be a trend in research in this area.

CONCLUSION

This bibliometric analysis summarises the disease mapping and some of the mechanisms of acupuncture's antioxidant effects. Neurological disorders such as Parkinson's disease, vascular dementia, and stroke are major research areas in this field. Pain and inflammation may be a direction for future research.

A systematic review and meta-analysis of pteridines in mild cognitive impairment and Alzheimer's disease

BACKGROUND

Alterations in specific pteridine metabolites, particularly neopterin, biopterin, and tetrahydrobiopterin have been reported in mild cognitive impairment, Alzheimer's disease, and other types of dementia. However, the available evidence regarding such alterations has not been comprehensively and critically appraised.

METHODS

We systematically reviewed studies reporting the concentrations of biopterin, tetrahydrobiopterin, and neopterin in different biological fluids in patients with mild cognitive impairment, Alzheimer's disease or other types of dementia, and healthy controls. Electronic databases were searched from inception to 29 February 2024.

RESULTS

Overall, there were no significant differences in plasma/serum concentrations of neopterin between patients with mild cognitive impairment, Alzheimer's disease, or other types of dementia, when grouped together, and healthy controls after adjusting for publication bias (11 studies, standard mean difference, SMD = 0.20, 95% CI -0.02 to 0.41, p = 0.076). In meta-regression and subgroup analysis, the effect size was significantly associated with age, number of participants, study continent, presence of mild cognitive impairment, presence of Alzheimer's disease, analytical method, and assessment of serum vs. plasma. One study reported higher urine neopterin in patients with Alzheimer's disease vs. controls whereas another study reported non-significant between-group differences in cerebrospinal neopterin. The cerebrospinal fluid concentrations of biopterin were significantly lower in patients with Alzheimer's disease vs. controls (two studies, SMD = -0.75, 95% CI -1.23 to -0.27, p = 0.002; I2 = 0.0%, p = 0.46). One study showed non-significant between-group differences in plasma biopterin whereas another study showed higher concentrations of urine biopterin in patients with Alzheimer's disease. Our search did not identify studies investigating tetrahydrobiopterin.

CONCLUSION

Our study showed no significant differences in circulating neopterin between patients with mild cognitive impairment, Alzheimer's disease, or other types of dementia, when grouped together, and healthy controls. The significant associations observed between the effect size and mild cognitive impairment and Alzheimer's disease in subgroup analysis warrant further investigation. (PROSPERO registration number: CRD42024523478).

The impact of cardiovascular and cerebrovascular disease on the risk of dementia in rheumatoid arthritis: A mediation analysis

OBJECTIVE

To examine the role of cardiovascular disease (CVD) as a mediator in the pathway between rheumatoid arthritis (RA) and Alzheimer's disease and related dementias (ADRD).

METHODS

This retrospective population-based study included patients over 50 years of age with incident RA, who met the 1987 ACR criteria in 1980-2014. This cohort was matched 1:1 on age, sex and index year to comparators without RA. Information on CVD events was manually extracted from electronic health records. The relationships between RA, CVD and ADRD were examined using Cox proportional hazard models. Time dependent mediation analysis was used to examine the role of CVD as a mediator between RA and ADRD.

RESULTS

1754 individuals were included (877 persons with RA and 877 comparators without RA). During follow-up, 105 patients with RA and 102 individuals without RA developed ADRD; 444 patients with RA and 375 individuals without RA developed CVD. There was a non-significant association between RA and ADRD both without (aHR 1.27, 95 % CI 0.96, 1.69) and with (aHR 1.27, 95 % CI 0.95,1.68) CVD as a time dependent mediator. The mediation effect of any CVD on ADRD risk was not significant (p = 0.84). We found a significant interaction between RA and CVD on the risk of ADRD (aHR 1.95, 95 % CI 1.11, 3.42; p = 0.021).

CONCLUSIONS

The risk of ADRD in RA appears to be increased mainly in the presence of CVD. CVD was not a significant mediator on the risk of ADRD in RA. There was a significant synergistic effect of RA and CVD on ADRD risk.

Lipids, lipoproteins, and apolipoproteins: Associations with cognition and dementia

Due to increasing lifespan and aging populations globally there has been a steep rise in late-life dementia, which is now the second most common cause of death in high-income countries. In general, dementia can be divided into two major groups: Alzheimer's disease (AD) and vascular-related dementia (VD). AD is pathologically characterised by senile plaques containing amyloid-β and neurofibrillary tangles composed of hyperphosphorylated tau, whereas VD is dominated by vascular pathology such as cerebral small vessel disease, major strokes, and white matter lesions. Recently, the importance of vascular components in AD is increasingly recognized and it is estimated that up to 45 % of all dementia cases can be prevented by preventing or treating midlife cardiovascular risk factors such as physical inactivity, diabetes, and hypertension. Even though the brain contains approximately 25 % of the total body cholesterol pool, and several genetic variants related to the lipid metabolism have been identified in genome-wide associations studies of AD, the role of lipids, lipoproteins, and apolipoproteins in dementia risk is less well-known. In this review, we go through the current literature on lipids, lipoproteins, and apolipoproteins and risk of dementia. We conclude that the evidence is primarily insufficient or conflicting, possibly due to nonoptimal study designs. The future calls for large, prospective studies of midlife measurements of lipids, lipoproteins, and apolipoproteins and one-sample, individual level data Mendelian randomization studies to overcome survival bias. However, the current literature suggests that it is safe to say that what is good for the heart is good for the brain.

Innovation at the Intersection: Emerging Translational Research in Neurology and Psychiatry

Translational research in neurological and psychiatric diseases is a rapidly advancing field that promises to redefine our approach to these complex conditions [...].

Circulating arginine metabolites in Alzheimer's disease and vascular dementia: A systematic review and meta-analysis

BACKGROUND

Alterations in nitric oxide (NO) synthesis have been reported in Alzheimer's disease and vascular dementia. However, as the measurement of NO in biological samples is analytically challenging, alternative, stable circulatory biomarkers of NO synthesis may be useful to unravel new pathophysiological mechanisms and treatment targets in dementia.

METHODS

We conducted a systematic review and meta-analysis of the circulating concentrations of arginine metabolites linked to NO synthesis, arginine, citrulline, asymmetric (ADMA) and symmetric (SDMA) dimethylarginine, and ornithine, in Alzheimer's disease and vascular dementia. We searched for relevant studies in PubMed, Scopus, and Web of Science from inception to the 31st of May 2023. The JBI checklist and GRADE were used to assess the risk of bias and the certainty of evidence, respectively.

RESULTS

In 14 selected studies, there were no significant between-group differences in arginine and ornithine concentrations. By contrast, compared to controls, patients with dementia had significantly higher ADMA (standard mean difference, SMD=0.62, 95% CI 0.06-1.19, p = 0.029), SDMA (SMD=0.70, 95% CI 0.34-1.35, p<0.001), and citrulline concentrations (SMD=0.50, 95% CI 0.08-0.91, p = 0.018). In subgroup analysis, the effect size was significantly associated with treatment with cholinesterase inhibitors and/or antipsychotics for ADMA, and underlying disorder (Alzheimer's disease), study continent, and analytical method for citrulline.

CONCLUSION

Alterations in ADMA, SDMA, and citrulline, biomarkers of NO synthesis, may be useful to investigate the pathophysiology of different forms of dementia and identify novel therapeutic strategies. (PROSPERO registration number: CRD42023439528).

COVID-19 and Alzheimer's Disease Share Common Neurological and Ophthalmological Manifestations: A Bidirectional Risk in the Post-Pandemic Future

A growing body of evidence indicates that a neuropathological cross-talk takes place between the coronavirus disease 2019 (COVID-19) -the pandemic severe pneumonia that has had a tremendous impact on the global economy and health since three years after its outbreak in December 2019- and Alzheimer's Disease (AD), the leading cause of dementia among human beings, reaching 139 million by the year 2050. Even though COVID-19 is a primary respiratory disease, its causative agent, the so-called Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), is also endowed with high neuro-invasive potential (Neurocovid). The neurological complications of COVID-19, resulting from the direct viral entry into the Central Nervous System (CNS) and/or indirect systemic inflammation and dysregulated activation of immune response, encompass memory decline and anosmia which are typically associated with AD symptomatology. In addition, patients diagnosed with AD are more vulnerable to SARS-CoV-2 infection and are inclined to more severe clinical outcomes. In the present review, we better elucidate the intimate connection between COVID-19 and AD by summarizing the involved risk factors/targets and the underlying biological mechanisms shared by these two disorders with a particular focus on the Angiotensin-Converting Enzyme 2 (ACE2) receptor, APOlipoprotein E (APOE), aging, neuroinflammation and cellular pathways associated with the Amyloid Precursor Protein (APP)/Amyloid beta (Aβ) and tau neuropathologies. Finally, the involvement of ophthalmological manifestations, including vitreo-retinal abnormalities and visual deficits, in both COVID-19 and AD are also discussed. Understanding the common physiopathological aspects linking COVID-19 and AD will pave the way to novel management and diagnostic/therapeutic approaches to cope with them in the post-pandemic future.

Brain-derived neurotrophic factor gene polymorphism affects cognitive function and neurofilament light chain level in patients with subcortical ischaemic vascular dementia

Objective

To investigate the effects of brain-derived neurotrophic factor (BDNF) gene polymorphism on cognitive function, neuroimaging and blood biological markers in patients with subcortical ischaemic vascular dementia (SIVD).

Methods

A total of 81 patients with SIVD were included. According to their BDNF gene polymorphism, the participants were divided into the Val/Val (n = 26), Val/Met (n = 35), and Met/Met (n = 20) groups. A comprehensive neuropsychological evaluation and multimodal brain MRI scan were performed. MRI markers for small vessel disease were visually rated or quantitatively analysed. Moreover, 52 patients were further evaluated with blood marker assays, including amyloid beta (Aβ), phosphorylated tau at threonine-181 (P-tau181), glial fibrillary acidic protein (GFAP), total tau (T-tau) and neurofilament light chain (NfL).

Results

There were no significant differences in demographics, disease duration or MRI markers of small vessel disease between the three groups. Compared with the Val/Val and Val/Met groups, the Met/Met group showed worse performance in the verbal fluency test and higher levels of plasma NfL.

Conclusion

The rs6265 polymorphism of the BDNF gene is associated with semantic language fluency in patients with SIVD. The Met genotype may be a risk factor for cognitive impairment and neuronal injury.

Recent Development of Novel Aminoethyl-Substituted Chalcones as Potential Drug Candidates for the Treatment of Alzheimer's Disease

No drug on the market, as a single entity, participates in different pathways involved in the pathology of Alzheimer's disease. The current study is aimed at the exploration of multifunctional chalcone derivatives which can act on multiple targets involved in Alzheimer's disease. A series of novel aminoethyl-substituted chalcones have been developed using in silico approaches (scaffold morphing, molecular docking, and ADME) and reported synthetic methods. The synthesized analogs were characterized and evaluated biologically using different in vitro assays against AChE, AGEs, and radical formation. Among all compounds, compound PS-10 was found to have potent AChE inhibitory activity (IC50 = 15.3 nM), even more than the standard drug (IC50 = 15.68 nM). Further, the in vivo evaluation of PS-10 against STZ-induced dementia in rats showed memory improvement (Morris Water Maze test) in rats. Also, PS-10 inhibited STZ-induced brain AChE activity and oxidative stress, further strengthening the observed in vitro effects. Further, the molecular dynamic simulation studies displayed the stability of the PS-10 and AChE complex. The novel aminoethyl-substituted chalcones might be considered potential multifunctional anti-Alzheimer's molecules.

Durative sleep fragmentation with or without hypertension suppress rapid eye movement sleep and generate cerebrovascular dysfunction

Either hypertension or chronic insomnia is the risk factor of developing vascular dementia. Durative hypertension can induce vascular remodeling and is used for modeling small vessel disease in rodents. It remains undetermined if the combination of hypertension and sleep disturbance exacerbates vascular dysfunction or pathologies. Previously, we found chronic sleep fragmentation (SF) dampened cognition in young mice without disease predispositions. In the current study, we superimposed SF with hypertension modeling in young mice. Angiotensin II (AngII)-releasing osmotic mini pumps were subcutaneously implanted to generate persistent hypertension, while sham surgeries were performed as controls. Sleep fragmentation with repetitive arousals (10 s every 2 min) during light-on 12 h for consecutive 30 days, while mice undergoing normal sleep (NS) processes were set as controls. Sleep architectures, whisker-stimulated cerebral blood flow (CBF) changes, vascular responsiveness as well as vascular pathologies were compared among normal sleep plus sham (NS + sham), SF plus sham (SF + sham), normal sleep plus AngII (NS + AngII), and SF plus AngII (SF + AngII) groups. SF and hypertension both alter sleep structures, particularly suppressing REM sleep. SF no matter if combined with hypertension strongly suppressed whisker-stimulated CBF increase, suggesting the tight association with cognitive decline. Hypertension modeling sensitizes vascular responsiveness toward a vasoactive agent, Acetylcholine (ACh, 5 mg/ml, 10 μl) delivered via cisterna magna infusion, while SF exhibits a similar but much milder effect. None of the modeling above was sufficient to induce arterial or arteriole vascular remodeling, but SF or SF plus hypertension increased vascular network density constructed by all categories of cerebral vessels. The current study would potentially help understand the pathogenesis of vascular dementia, and the interconnection between sleep and vascular health.

Carotid dysfunction in senescent female mice is mediated by increased α1A-adrenoceptor activity and COX-derived vasoconstrictor prostanoids

α-Adrenergic receptors are crucial regulators of vascular hemodynamics and essential pharmacological targets for cardiovascular diseases. With aging, there is an increase in sympathetic activation, which could contribute to the progression of aging-associated cardiovascular dysfunction, including stroke. Nevertheless, there is little information directly associating adrenergic receptor dysfunction in the blood vessels of aged females. This study determined the role of a-adrenergic receptors in carotid dysfunction of senescent female mice (accelerated-senescence prone, SAMP8), compared with a nonsenescent (accelerated-senescence prone, SAMR1). Vasoconstriction to phenylephrine (Phe) was markedly increased in common carotid artery of SAMP8 [area under the curve (AUC), 527 ± 53] compared with SAMR1 (AUC, 334 ± 30, P = 0.006). There were no changes in vascular responses to the vasoconstrictor agent U46619 or the vasodilators acetylcholine (ACh) and sodium nitroprusside (NPS). Hyperactivity to Phe in female SAMP8 was reduced by cyclooxygenase-1 and cyclooxygenase-2 inhibition and associated with augmented ratio of TXA2/PGI2 release (SAMR1, 1.1 ± 0.1 vs. SAMP8, 2.1 ± 0.3, P = 0.007). However, no changes in cyclooxygenase expression were seen in SAMP8 carotids. Selective α1A-receptor antagonism markedly reduced maximal contraction, whereas α1D antagonism induced a minor shift in Phe contraction in SAMP8 carotids. Ligand binding analysis revealed a threefold increase of α-adrenergic receptor density in smooth muscle cells (VSMCs) of SAMP8 vs. SAMR1. Phe rapidly increased intracellular calcium (Cai2+) in VSMCs via the α1A-receptor, with a higher peak in VSMCs from SAMP8. In conclusion, senescence intensifies vasoconstriction mediated by α1A-adrenergic signaling in the carotid of female mice by mechanisms involving increased Cai2+ and release of cyclooxygenase-derived prostanoids.NEW & NOTEWORTHY The present study provides evidence that senescence induces hyperreactivity of α1-adrenoceptor-mediated contraction of the common carotid. Impairment of α1-adrenoceptor responses is linked to increased Ca2+ influx and release of COX-derived vasoconstrictor prostanoids, contributing to carotid dysfunction in the murine model of female senescence (SAMP8). Increased reactivity of the common carotid artery during senescence may lead to morphological and functional changes in arteries of the cerebral microcirculation and contribute to cognitive decline in females. Because the elderly population is growing, elucidating the mechanisms of aging- and sex-associated vascular dysfunction is critical to better direct pharmacological and lifestyle interventions to prevent cardiovascular risk in both sexes.