Summative Effects of Vascular Risk Factors on the Progression of Alzheimer Disease

Cardiovascular disease risk models and dementia or cognitive decline: a systematic review

Background

Health cognitive promotion and protection is a critical topic. With the world's aging population and rising life expectancy, there will be many people living with highly age-related dementia illnesses. Cardiovascular disease (CVD) and dementia share the same risk factors, such as unhealthy lifestyles and metabolic factors. These recognized risks associated with CVD and dementia frequently co-occur. CVD risk models may have a close association with dementia and cognitive decline. So, this systematic review aimed to determine whether CVD risk models were connected with dementia or cognitive decline and compare the predictive ability of various models.

Methods

PubMed, Web of Science, PsychINFO, Embase, Cochrane Library, CNKI, Sinomed, and WanFang were searched from 1 January 2014 until 16 February 2023. Only CVD risk models were included. We used the Newcastle-Ottawa scale (NOS) for the quality assessment of included cohort studies and the Agency for Healthcare Research and Quality (AHRQ) for cross-sectional studies. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement's guidelines were followed in this systematic study.

Results

In all, 9,718 references were screened, of which 22 articles were included. A total of 15 CVD risk models were summarized. Except for the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) health index, the other 14 CVD risk models were associated with dementia and cognitive decline. In comparison, different CVD risk models and domain-specific cognitive function correlation variation depended on cohort characteristics, risk models, cognitive function tests, and study designs. Moreover, it needed to be clarified when comparing the predicting performance of different CVD risk models.

Conclusion

It is significant for public health to improve disease risk prediction and prevention and mitigate the potential adverse effects of the heart on the brain. More cohort studies are warranted to prove the correlation between CVD risk models and cognitive function. Moreover, further studies are encouraged to compare the efficacy of CVD risk models in predicting cognitive disorders.

Exploring the relationship between patient-relevant outcomes and Alzheimer's disease progression assessed using the clinical dementia rating scale: a systematic literature review

Background

People with Alzheimer's disease (AD) have difficulties in performing activities of daily living (ADLs) as the disease progresses, commonly experience neuropsychiatric symptoms (NPS), and often have comorbidities such as cardiovascular disease. These factors all contribute to a requirement for care and considerable healthcare costs in AD. The Clinical Dementia Rating (CDR) scale is a widely used measure of dementia staging, but the correlations between scores on this scale and patient-/care partner-relevant outcomes have not been characterized fully. We conducted a systematic literature review to address this evidence gap.

Methods

Embase, MEDLINE, and the Cochrane Library were searched September 13, 2022, to identify published studies (no restriction by date or country) in populations with mild cognitive impairment due to AD or AD dementia. Studies of interest reported data on the relationships between CDR Global or CDR-Sum of Boxes (CDR-SB) scores and outcomes including NPS, comorbidities, ADLs, nursing home placement, healthcare costs, and resource use.

Results

Overall, 58 studies met the inclusion criteria (42 focusing on comorbidities, 14 on ADLs or dependence, five on nursing home placement, and six on economic outcomes). CDR/CDR-SB scores were correlated with the frequency of multiple NPS and with total scores on the Neuropsychiatric Inventory. For cardiovascular comorbidities, no single risk factor was consistently linked to AD progression. Increasing CDR/CDR-SB scores were correlated with decline in multiple different measures of ADLs and were also associated with nursing home placement and increasing costs of care.

Conclusion

NPS, ADLs, and costs of care are clearly linked to AD progression, as measured using CDR Global or CDR-SB scores, from the earliest stages of disease. This indicates that scores derived from the CDR are a meaningful way to describe the severity and burden of AD for patients and care partners across disease stages.

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD.

Mental and physical health pathways linking insomnia symptoms to cognitive performance 14 years later

STUDY OBJECTIVES

Insomnia may be a modifiable risk factor for later-life cognitive impairment. We investigated: (1) which insomnia symptoms are associated with subsequent cognitive functioning across domains; (2) whether insomnia-cognition associations are mediated by mental and physical health; and (3) whether these associations are modified by gender.

METHODS

Participants included 2595 adults ages 51-88 at baseline (Mage=64.00 ± 6.66, 64.5% women) in the Health and Retirement Study. The frequency of insomnia symptoms (difficulty initiating sleep, night time awakenings, early awakenings, and feeling unrested upon awakening) at baseline (2002) were quantified using a modified Jenkins Sleep Questionnaire. Cognition was assessed in 2016 via the Harmonized Cognitive Assessment Protocol and operationalized with factor scores corresponding to five domains. Depressive symptoms and vascular conditions in 2014 were assessed via self-report. Structural equation models estimated total, indirect, and direct effects of insomnia symptoms on subsequent cognition through depressive symptoms and vascular diseases, controlling for baseline sociodemographic and global cognition.

RESULTS

Frequent difficulty initiating sleep was associated with poorer episodic memory, executive function, language, visuoconstruction, and processing speed 14 years later (-0.06 ≤ β ≤ -0.04; equivalent to 2.2-3.4 years of aging). Depressive symptoms explained 12.3%-19.5% of these associations and vascular disease explained 6.3%-14.6% of non-memory associations. No other insomnia symptoms were associated with cognition, and no associations were modified by gender.

CONCLUSIONS

Difficulty initiating sleep in later life may predict future cognitive impairment through multiple pathways. Future research with longitudinal assessments of insomnia, insomnia treatments, and cognition is needed to evaluate insomnia as a potential intervention target to optimize cognitive aging.

Dl-3-n-butylphthalide promotes synaptic plasticity by activating the Akt/ERK signaling pathway and reduces the blood-brain barrier leakage by inhibiting the HIF-1α/MMP signaling pathway in vascular dementia model mice

AIMS

DL-3-n-butylphthalide (NBP) exerts beneficial effects on global cognitive functions, but the underlying molecular mechanisms are still poorly understood. The present study aimed to investigate whether NBP mediates synaptic plasticity and blood-brain barrier (BBB) function, which play a pivotal role in the pathogenesis of vascular dementia (VaD), in a mouse model of bilateral common carotid artery stenosis (BCAS).

METHODS

NBP was administered to model mice at a dose of 80 mg/kg by gavage for 28 days after surgery. Cognitive function was evaluated by behavioral tests, and hippocampal synaptic plasticity was evaluated by in vivo electrophysiological recording. Cerebral blood flow (CBF), hippocampal volume, and white matter integrity were measured with laser speckle imaging (LSI) and MRI. In addition, BBB leakage and the expression of proteins related to the Akt/ERK and HIF-1α/MMP signaling pathways were assessed by biochemical assays.

RESULTS

NBP treatment alleviated cognitive impairment, hippocampal atrophy, and synaptic plasticity impairment induced by BCAS. In addition, NBP treatment increased CBF, promoted white matter integrity, and decreased BBB leakage. Regarding the molecular mechanisms, in mice  with BCAS, NBP may activate the Akt/ERK signaling pathway, which upregulates the expression of synapse-associated proteins, and it may also inhibit the HIF-1α/MMP signaling pathway, thereby increasing the expression of tight junction (TJ) proteins.

CONCLUSION

In conclusion, our results demonstrated the therapeutic effects of NBP in improving cognitive function via a wide range of targets in mice subjected to BCAS.

Visit-to-Visit Blood Pressure Variability and Cognitive Decline in Apolipoprotein ɛ4 Carriers versus Apolipoprotein ɛ3 Homozygotes

BACKGROUND

Blood pressure variability (BPV) is associated with cognitive decline and Alzheimer's disease (AD), but relationships with AD risk gene apolipoprotein (APOE) ɛ4 remain understudied.

OBJECTIVE

Examined the longitudinal relationship between BPV and cognitive change in APOE ɛ4 carriers and APOE ɛ3 homozygotes.

METHODS

1,194 Alzheimer's Disease Neuroimaging Initiative participants (554 APOE ɛ4 carriers) underwent 3-4 blood pressure measurements between study baseline and 12-month follow-up. Visit-to-visit BPV was calculated as variability independent of mean over these 12 months. Participants subsequently underwent ≥1 neuropsychological exam at 12-month follow-up or later (up to 156 months later). Composite scores for the domains of memory, language, executive function, and visuospatial abilities were determined. Linear mixed models examined the 3-way interaction of BPV×APOE ɛ4 carrier status x time predicting change in composite scores.

RESULTS

Higher systolic BPV predicted greater decline in memory (+1 SD increase of BPV: β= -0.001, p < 0.001) and language (β= -0.002, p < 0.0001) among APOE ɛ4 carriers, but not APOE ɛ3 homozygotes (memory: +1 SD increase of BPV: β= 0.0001, p = 0.57; language: β= 0.0001, p = 0.72). Systolic BPV was not significantly associated with change in executive function or visuospatial abilities in APOE ɛ4 carriers (ps = 0.08-0.16) or APOE ɛ3 homozygotes (ps = 0.48-0.12).

CONCLUSION

Cognitive decline associated with high BPV may be specifically accelerated among APOE ɛ4 carriers.

Early-stage differentiation between Alzheimer's disease and frontotemporal lobe degeneration: Clinical, neuropsychology, and neuroimaging features

BACKGROUND

Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) are the two most common forms of neurodegenerative dementia. Although both of them have well-established diagnostic criteria, achieving early diagnosis remains challenging. Here, we aimed to make the differential diagnosis of AD and FTLD from clinical, neuropsychological, and neuroimaging features.

MATERIALS AND METHODS

In this retrospective study, we selected 95 patients with PET-CT defined AD and 106 patients with PET-CT/biomarker-defined FTLD. We performed structured chart examination to collect clinical data and ascertain clinical features. A series of neuropsychological scales were used to assess the neuropsychological characteristics of patients. Automatic tissue segmentation of brain by Dr. Brain tool was used to collect multi-parameter volumetric measurements from different brain areas. All patients' structural neuroimage data were analyzed to obtain brain structure and white matter hyperintensities (WMH) quantitative data.

RESULTS

The prevalence of vascular disease associated factors was higher in AD patients than that in FTLD group. 56.84% of patients with AD carried at least one APOE ε4 allele, which is much high than that in FTLD patients. The first symptoms of AD patients were mostly cognitive impairment rather than behavioral abnormalities. In contrast, behavioral abnormalities were the prominent early manifestations of FTLD, and few patients may be accompanied by memory impairment and motor symptoms. In direct comparison, patients with AD had slightly more posterior lesions and less frontal atrophy, whereas patients with FTLD had more frontotemporal atrophy and less posterior lesions. The WMH burden of AD was significantly higher, especially in cortical areas, while the WMH burden of FTLD was higher in periventricular areas.

CONCLUSION

These results indicate that dynamic evaluation of cognitive function, behavioral and psychological symptoms, and multimodal neuroimaging are helpful for the early diagnosis and differentiation between AD and FTLD.

Transcranial magnetic stimulation treatment in Alzheimer's disease: a meta-analysis of its efficacy as a function of protocol characteristics and degree of personalization

Alzheimer's disease (AD) represents the most common type of neurodegenerative disorder. Although our knowledge on the causes of AD remains limited and no curative treatments are available, several interventions have been proposed in trying to improve patients' symptomatology. Among those, transcranial magnetic stimulation (TMS) has been shown a promising, safe and noninvasive intervention to improve global cognitive functioning. Nevertheless, we currently lack agreement between research studies on the optimal stimulation protocol yielding the highest efficacy in these patients. To answer this query, we conducted a systematic literature search in PubMed, PsycINFO and Scopus databases and meta-analysis of studies published in the last 10 years (2010-2021) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Differently from prior published meta-analytic work, we investigated whether protocols that considered participants-specific neuroimaging scans for the selection of individualized stimulation targets held more successful outcomes compared to those relying on a generalized targeting selection criteria. We then compared the effect sizes of subsets of studies based on additional protocol characteristics (frequency, duration of intervention, number of stimulation sites, use of concomitant cognitive training and patients' educational level). Our results confirm TMS efficacy in improving global cognitive functioning in mild-to-moderate AD patients, but also highlight the flaws of current protocols characteristics, including a possible lack of sufficient personalization in stimulation protocols.

Blood-brain barrier leakage in Alzheimer's disease: From discovery to clinical relevance

Alzheimer's disease (AD) is the most common form of dementia. AD brain pathology starts decades before the onset of clinical symptoms. One early pathological hallmark is blood-brain barrier dysfunction characterized by barrier leakage and associated with cognitive decline. In this review, we summarize the existing literature on the extent and clinical relevance of barrier leakage in AD. First, we focus on AD animal models and their susceptibility to barrier leakage based on age and genetic background. Second, we re-examine barrier dysfunction in clinical and postmortem studies, summarize changes that lead to barrier leakage in patients and highlight the clinical relevance of barrier leakage in AD. Third, we summarize signaling mechanisms that link barrier leakage to neurodegeneration and cognitive decline in AD. Finally, we discuss clinical relevance and potential therapeutic strategies and provide future perspectives on investigating barrier leakage in AD. Identifying mechanistic steps underlying barrier leakage has the potential to unravel new targets that can be used to develop novel therapeutic strategies to repair barrier leakage and slow cognitive decline in AD and AD-related dementias.

Absence of an Association between Macular Degeneration and Young-Onset Dementia

A few population-based studies have reported an association between prior age-related macular degeneration and senile dementia. No study has explored a possible link between prior macular degeneration and young-onset dementia (YOD). This case–control study aimed to evaluate the association of YOD with prior macular degeneration diagnosed in the 5-year period before their index date. Data for this retrospective observational study were retrieved from Taiwan’s National Health Insurance (NHI) dataset. A total of 36,577 patients with newly diagnosed YOD from January 2010 to December 2017 were identified as the study cohort, assigning their diagnosis date as their index date. Comparison patients were identified by propensity score-matching (three per case, n = 109,731 controls) from the remaining NHI beneficiaries of the period, their index date being the date of their first ambulatory care claim in the year of diagnosis of their matched YOD case. Chi-square test revealed no significant difference in the prevalence of prior macular degeneration between cases and controls (1.1% vs. 1.0%, p = 0.111). Conditional logistic regression analysis also showed an unadjusted odds ratio (OR) for prior macular degeneration of 1.098 among cases relative to controls (95% CI: 0.9797–1.232). Adjusted analysis confirmed that YOD was not associated with prior macular degeneration, adjusted odds ratio 1.098 (95% CI = 0.979–1.232). We conclude that patients with macular degeneration are not at increased risk for YOD.

Association between Alzheimer's disease genes and trajectories of cognitive function decline in Han Chinese in Taiwan

Genetic background has been considered one of the important contributors to the rate of cognitive decline among patients with Alzheimer’s disease (AD). We conducted a 4-year longitudinal follow-up study, recruited 255 AD and 44 mild cognitive impairment (MCI) patients, and used a data-driven trajectory analysis to examine the influence of selected AD risk genes on the age for and the rate of cognitive decline in Han Chinese population. Genotyping of selected single-nucleotide polymorphisms in the APOE, ABCA7, SORL1, BIN1, GAB2, and CD33 genes was conducted, and a Bayesian hierarchical model was fitted to analyze the trajectories of cognitive decline among different genotypes. After adjusting for sex and education years, the APOE ε4 allele was associated with an earlier mean change of −2.39 years in the age at midpoint of cognitive decline, the G allele in ABCA7 rs3764650 was associated with an earlier mean change of −1.75 years, and the T allele in SORL1 rs3737529 was associated with a later mean change of 2.6 years. Additionally, the rate of cognitive decline was associated with the APOE ε4 allele and SORL1 rs3737529. In summary, APOE and SORL1 might be the most important genetic factors related to cognitive decline in Han Chinese population.

Role of Neuron and Glia in Alzheimer's Disease and Associated Vascular Dysfunction

Amyloidogenicity and vascular dysfunction are the key players in the pathogenesis of Alzheimer’s disease (AD), involving dysregulated cellular interactions. An intricate balance between neurons, astrocytes, microglia, oligodendrocytes and vascular cells sustains the normal neuronal circuits. Conversely, cerebrovascular diseases overlap neuropathologically with AD, and glial dyshomeostasis promotes AD-associated neurodegenerative cascade. While pathological hallmarks of AD primarily include amyloid-β (Aβ) plaques and neurofibrillary tangles, microvascular disorders, altered cerebral blood flow (CBF), and blood-brain barrier (BBB) permeability induce neuronal loss and synaptic atrophy. Accordingly, microglia-mediated inflammation and astrogliosis disrupt the homeostasis of the neuro-vascular unit and stimulate infiltration of circulating leukocytes into the brain. Large-scale genetic and epidemiological studies demonstrate a critical role of cellular crosstalk for altered immune response, metabolism, and vasculature in AD. The glia associated genetic risk factors include APOE, TREM2, CD33, PGRN, CR1, and NLRP3, which correlate with the deposition and altered phagocytosis of Aβ. Moreover, aging-dependent downregulation of astrocyte and microglial Aβ-degrading enzymes limits the neurotrophic and neurogenic role of glial cells and inhibits lysosomal degradation and clearance of Aβ. Microglial cells secrete IGF-1, and neurons show a reduced responsiveness to the neurotrophic IGF-1R/IRS-2/PI3K signaling pathway, generating amyloidogenic and vascular dyshomeostasis in AD. Glial signals connect to neural stem cells, and a shift in glial phenotype over the AD trajectory even affects adult neurogenesis and the neurovascular niche. Overall, the current review informs about the interaction of neuronal and glial cell types in AD pathogenesis and its critical association with cerebrovascular dysfunction.

Dl-3-n-butylphthalide regulates cholinergic dysfunction in chronic cerebral hypoperfusion rats

Objectives

To investigate whether dl-3-n-butylphthalide (NBP) affects cholinergic system function and ameliorates cognitive decline in a rat model of vascular dementia (VaD).

Methods

The VaD rat model was established by bilateral common carotid artery ligation (two-vessel occlusion, 2VO). Rats were divided into five groups: control, sham, 2VO, 2VO+NBP (80 mg/kg; intragastric), and 2VO+donepezil (1 mg/kg; intragastric). Treatments were administered once daily for 2 weeks from day 21 post-surgery. Spatial learning and memory were evaluated by Morris water maze performance. Hippocampal choline acetyltransferase (ChAT), acetylcholinesterase (AChE), vesicular acetylcholine transporter (VAChT), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) expressions were detected using immunohistochemistry, immunofluorescence, and real-time polymerase chain reaction methods.

Results

The daily escape latency was significantly longer in 2VO rats than in the sham or control groups, while the time spent in the target quadrant was significantly shorter. The daily escape latency of the 2VO+NBP group was significantly shorter compared with the 2VO group. Following NBP treatment, ChAT, AChE, VAChT, and BDNF expressions were significantly upregulated in the hippocampus.

Conclusions

Central cholinergic dysfunction may be involved in VaD pathogenesis. NBP treatment significantly improved spatial learning and memory in VaD rats, and may enhance cholinergic system function via BDNF-mediated neuroprotection.

Serum miR-128 Serves as a Potential Diagnostic Biomarker for Alzheimer's Disease

BACKGROUND

Although numerous microRNAs (miRNAs) have been discovered to participate in the progression of Alzheimer's disease (AD), they are still difficult to apply in clinical work. Thus, the identification of novel miRNAs and clarification of their clinical significance are importing for improving the diagnosis and treatment of AD. The purpose of this study was to analyze the expression of miR-128 and its diagnostic value in patients with AD.

PATIENTS AND METHODS

In this study, 117 AD patients and 106 controls were enrolled, and the demographic data, biochemical parameters and serum miR-128 levels were collected. These data were then used to build a logistic regression model, and receiver operating characteristic (ROC) curves were drawn to evaluate the diagnostic value of miR-128. The relationships between miR-128 and inflammatory factors (IL-1β/TNF-α) were also analyzed from clinical serum data.

RESULTS

Our study found that miR-128 was significantly upregulated in the serum samples of AD patients compared with controls, and that this upregulation was negatively correlated with Mini-Mental State Examination (MMSE) scores (r = -0.687, P< 0.01). ROC curve showed that the area under the curve of miR-128 was 0.831. Logistic regression analyses showed that glycosylated hemoglobin (HbA1c) levels, low-density lipoprotein (LDL) levels, MMSE scores and serum miR-128 levels were statistically significant (P< 0.01), and the ROC curve of the combined detection of these variables was 0.906. The serum miR-128 levels in AD patients were positively correlated with the serum IL-1β (r=0.798, P<0.01) and serum TNF-α levels (r=0.733, P<0.01).

CONCLUSION

Serum miR-128 is a candidate diagnostic biomarker in AD patients who achieved good diagnostic performance when used alone or in combination with other factors and may have the potential to be a novel therapeutic target for neuroinflammation.

Modifiable, Non-Modifiable, and Clinical Factors Associated with Progression of Alzheimer's Disease

There is an extensive literature relating to factors associated with the development of Alzheimer's disease (AD), but less is known about factors which may contribute to its progression. This review examined the literature with regard to 15 factors which were suggested by PubMed search to be positively associated with the cognitive and/or neuropathological progression of AD. The factors were grouped as potentially modifiable (vascular risk factors, comorbidities, malnutrition, educational level, inflammation, and oxidative stress), non-modifiable (age at clinical onset, family history of dementia, gender, Apolipoprotein E ɛ4, genetic variants, and altered gene regulation), and clinical (baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs). Although conflicting results were found for the majority of factors, a positive association was found in nearly all studies which investigated the relationship of six factors to AD progression: malnutrition, genetic variants, altered gene regulation, baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs. Whether these or other factors which have been suggested to be associated with AD progression actually influence the rate of decline of AD patients is unclear. Therapeutic approaches which include addressing of modifiable factors associated with AD progression should be considered.

Attention and Functional Connectivity Among Patients With Early-Stage Subcortical Ischemic Vascular Disease and Alzheimer's Disease

The current study compared attention profiles and functional connectivity of frontal regions in patients with early-stage subcortical ischemic vascular disease (SIVD) and Alzheimer's disease (AD). Twenty patients with SIVD, 32 patients with AD, and 23 subjects with normal cognition (NC) received cognition and resting-state functional MRI (rs-fMRI) evaluations. The Cognitive Abilities Screening Instrument (CASI) was used to assess global cognition, and simple attention, processing speed, divided attention, and vigilance/sustained attention were evaluated using the Digit Span Forward, Trail Making Test, Symbol Digit Modality Test, and Conners Continuous Performance Test, respectively. Voxel-based regional homogeneity (ReHo) derived from rs-fMRI data was analyzed to identify significant clusters, which were further correlated with attention profiles. Although the patients with SIVD and AD had comparable global cognitive ability, those with SIVD exhibited worse divided attention and vigilance/sustained attention than those with AD. Compared with the NC group, the patients with SIVD exhibited decreased ReHo within the right middle frontal gyrus (MFG) and left anterior cingulate gyrus (ACG), whereas the patients with AD exhibited increased ReHo within the right orbital part of frontal regions. Correlations between these three clusters with attention exhibited distinct patterns according to the dementia subtype, as did attention indices with significance in predicting global cognition. In summary, our study suggested that worse attention performance was associated with functional disconnection within the frontal regions among patients with SIVD than in those with AD. Frontal functional disconnection may underlie the pathogenesis responsible for defective divided attention, vigilance/sustained attention, and notable within-group variations identified in SIVD.

The relationship between urinary Alzheimer-associated neuronal thread protein and blood biochemical indicators in the general population

Urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) is elevated in early Alzheimer's disease (AD) and mild cognitive impairment, and is considered a biomarker for the early diagnosis of AD. However, it has not yet been investigated whether urinary AD7c-NTP is elevated with increases in blood biochemical indicators related to AD risk factors. We recruited 2180 participants, aged 35-93 years, from communities of four districts in Beijing. Blood biochemical indicators, including blood glucose, blood lipids, renal function, and high-sensitivity C-reactive protein, were measured using routine methods. Urinary AD7c-NTP was detected using an enzyme-linked immunosorbent assay AD7c-NTP kit. In the general population, there were no significant differences in urinary AD7c-NTP levels in subjects with different Mini-Mental State Examination levels or C-reactive protein values. After adjusting for age and sex, there were significant differences in urinary AD7c-NTP levels between different education levels, marital statuses, blood glucose, blood lipids, and kidney function. There was a negative correlation between urinary AD7c-NTP levels and serum creatinine (r = -0.128). There was a positive correlation between urinary AD7c-NTP levels and HbA1c (r = 0.104), insulin (r = 0.101), and triglycerides (r = 0.093). Urinary AD7c-NTP might be useful as a potential indicator to predict AD risk.

Cortical atrophy mediates the accumulating effects of vascular risk factors on cognitive decline in the Alzheimer's disease spectrum

There are increasing concerns regarding the association of vascular risk factors (VRFs) and cognitive decline in the Alzheimer's disease (AD) spectrum. Currently, we investigated whether the accumulating effects of VRFs influenced gray matter volumes and subsequently led to cognitive decline in the AD spectrum. Mediation analysis was used to explore the association among VRFs, cortical atrophy, and cognition in the AD spectrum. 123 AD spectrum were recruited and VRF scores were constructed. Multivariate linear regression analysis revealed that higher VRF scores were correlated with lower Mini-Mental State Examination scores and higher Alzheimer's Disease Assessment Scale-Cognitive Subscale scores, indicating higher VRF scores lead to severer cognitive decline in the AD spectrum. In addition, subjects with higher VRF scores suffered severe cortical atrophy, especially in medial prefrontal cortex and medial temporal lobe. More importantly, common circuits of VRFs- and cognitive decline associated with gray matter atrophy were identified. Further, using mediation analysis, we demonstrated that cortical atrophy regions significantly mediated the relationship between VRF scores and cognitive decline in the AD spectrum. These findings highlight the importance of accumulating risk in the vascular contribution to AD spectrum, and targeting VRFs may provide new strategies for the therapeutic and prevention of AD.

Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease

INTRODUCTION

Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice.

AREAS COVERED

(i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations.

EXPERT OPINION

The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.