Association between the APOE ε4 Allele and Late-Onset Alzheimer's Disease in an Ecuadorian Mestizo Population

ApoE Gene Polymorphism and Clinical, Biochemical, and Sociodemographic Characteristics of Alzheimer's Disease Patients From Northern and Southern Regions of Kazakhstan

BACKGROUND

Alzheimer's disease (AD) is the most frequent cause of dementia in seniors and is also one of the critical social issues of modern healthcare. Since AD is considered a multifactorial disease, the significance of particular risk factors in different ethnic populations is constantly reevaluated.

METHOD

The study group consisted of 181 patients with AD, and the control group included 244 healthy seniors comparable in sex and age to the dementia group. Our study compared clinical data, blood biochemical parameters, various sociodemographic characteristics, and ApoE gene polymorphism in patients diagnosed with AD from Kazakhstan's north (Astana city) and south (Almaty city) regions.

RESULTS

In our cohort, significant dementia-associated variables included smoking, clinically significant depression, dyslipidemia, impaired glucose metabolism, insulin resistance, and liver dysfunction. Notably, AD patients had higher HDL levels, lower ALT levels, and higher total bilirubin and AST/ALT ratios. The ApoE ɛ4 genotype, a well-known AD risk factor, was more prevalent in the northern AD group. Additionally, participants from Astana city had a higher incidence of strokes, potentially linked to elevated LDL levels, while Almaty city residents exhibited a higher prevalence of clinically severe depression.

DISCUSSION

These findings underscore the importance of considering bio-geographic and environmental factors in AD research. The study's outcomes may aid in further research and the development of personalized approaches for managing and treating AD in distinct geographical regions.

Postoperative Delirium and Neurocognitive Disorders: A Comprehensive Review of Pathophysiology, Risk Factors, and Management Strategies

Postoperative delirium (POD) and neurocognitive disorders (NCDs) are common and serious complications that can occur after surgery, particularly in older adults and those with preexisting cognitive impairments. These conditions are associated with significant morbidity, increased healthcare costs, and reduced quality of life. Understanding the underlying mechanisms, risk factors, and effective management strategies for POD and NCDs is critical for improving patient outcomes and reducing the burden on healthcare systems. This comprehensive review aims to synthesize current knowledge on the pathophysiology, risk factors, and management strategies for POD and NCDs. It explores the neurobiological and molecular mechanisms contributing to these conditions, identifies the patient-related, surgical, and environmental factors that increase risk, and evaluates pharmacological and non-pharmacological approaches to prevention and treatment. A thorough literature review was conducted using recent studies, clinical guidelines, and expert consensus to provide a detailed overview of the pathophysiology, risk factors, clinical presentation, prevention, and management of POD and NCDs. The pathophysiology of POD and NCDs involves complex interactions between neuroinflammatory processes, neurotransmitter imbalances, and brain network disruptions. Risk factors include advanced age, preexisting cognitive impairment, type and duration of surgery, and perioperative complications. Management strategies emphasize a multidisciplinary approach, incorporating preoperative optimization, careful intraoperative management, and postoperative interventions. Pharmacological treatments, such as antipsychotics, and non-pharmacological approaches, including environmental modifications and cognitive rehabilitation, play crucial roles in management. Postoperative delirium and NCDs are multifactorial conditions with significant impacts on surgical outcomes. Effective management requires a comprehensive understanding of their pathophysiology and risk factors and the implementation of targeted prevention and treatment strategies. Future research should focus on personalized approaches to prevention and treatment, further elucidation of mechanisms, and developing predictive models to enhance care for patients at risk of these neurocognitive complications.

Relation between Apolipoprotein E in Alzheimer's Disease and SARS-CoV-2 and their Treatment Strategy: A Review

COVID-19, which primarily affects the pulmonary system, turned out to be a global pandemic, whereas the effects on other systems are still unknown. SARS-CoV-2, binds to angiotensinconverting enzyme 2 (ACE2) receptors in the lungs, causing pneumonia-like symptoms. The same ACE receptors are also present in organs other than the lungs. Therefore, there is a need to study the impact of coronavirus on other human body organs. Recently, UK Biobank reports on the genetic risk factor of the virus attack. A double mutation in the apolipoprotein E (APOE4) allele has shown a significant role in COVID-19. The same APOE4 mutation has already been proven to hold a key role in developing early-onset Alzheimer's disease (EOAD). Despite this data, Alzheimer's disease is believed to be a comorbidity of COVID-19. Previous virus attacks on the same viral family, Coronaviridae, produced neurological effects like neurodegeneration, neuronal inflammation, and other central nervous system-related dysfunctions. Since the long-term implications of COVID-19 are unknown, more research into the impact of the virus on the central nervous system is needed. Both COVID-19 and AD share a common genetic factor, so that AD patients may have a greater risk of SARS-CoV-2. Here, in this review, we have briefly discussed the role of APOE4 in the pathogenesis of AD and SARS-CoV-2, along with their treatment strategy, current scenario, and possible future directions.

Investigation of MIF gene promoter variations and their haplotypes in the Alzheimer disease in Turkish population

In Alzheimer's disease, which is characterized by amyloid plaques and neurofibrillary tangles in the brain tissue, many components such as acute phase proteins, cytokines, and proteases contribute to the progression of the disease or are part of the pathological process. The macrophage migration inhibitory factor (MIF) gene encodes a cytokine, which is secreted by lymphocytes, and has a role in the pathogenesis of autoimmune/inflammatory diseases such as rheumatoid arthritis. The purpose of this study to investigate the association between Alzheimer disease and MIF gene promoter polymorphisms. The 205 patients with Alzheimer disease (AD) and 130 age-sex matched healthy individuals were investigated in terms of MIF -173 G/C and MIF -794 CATT polymorphisms. The genotyping of MIF -173 G/C was determined using the RT-PCR method. MIF-794 CATT polymorphism was analyzed using PCR and DNA Sequencing. In terms of binary genotypes and haplotypes, the 5/5-GC (p = 0.004), 6/7-GG (p = 0.02) and, 6/6-GG (p = 0.026) binary genotypes, and 5-C (p = 0.003), 7-G (p = 0.026) and 6-G (p = 0.025) haplotypes were differed significantly between the patients and the controls. This is the first study investigating the relationship between AD and MIF in terms of different genotypes, haplotypes and, alleles. The fact that the binary genotype and allele distributions are significantly different between the patient and control group, suggests that this MIF variants may play a role in the pathogenesis of AD.

A review of potential microbiome-gut-brain axis mediated neurocognitive conditions in persons living with HIV

The microbiome-gut-brain axis, or the various interactions between the gut microbiome and the brain, has been of recent interest in the context of precision medicine research for a variety of disease states. Persons living with human immunodeficiency virus (PLWH) experience higher degrees of neurocognitive decline than the general population, correlating with a disruption of the normal gut microbiome composition (i.e. dysbiosis). While the nature of this correlation remains to be determined, there is the potential that the microbiome-gut-brain axis contributes to the progression of this disease. Previous research has established that the pathology associated with HIV induces alterations in the composition of gut microbiome, including a shift from Bacteroides to Prevotella dominance, and compromises gut barrier integrity, which may promote microbial translocation and consequent systemic inflammation and exacerbation of neuroinflammation. Further, though the use of antiretroviral therapy has been found to partially counteract HIV-related dysbiosis, it may also induce its own dysbiosis patterns, presenting a unique challenge for this research. More recent research has suggested the gut microbiome as a target for therapeutic interventions to improve symptoms associated with a variety of disease states, including HIV. Early findings are promising and warrant further research regarding the gut microbiome as a potential modifiable factor to improve health outcomes for PLWH. This review will discuss the current knowledge concerning the neuropathogenesis of HIV in the brain, role of the gut microbiome in neuroinflammation, and the relationship between HIV-status and the gut microbiome, followed by a conclusion that synthesizes this information within the context of the microbiome-gut-brain axis among PLWH. This review will also highlight the limitations of existing studies and propose future directions of this research.

Telomere length and 8-hydroxy-2-deoxyguanosine as markers for early prediction of Alzheimer disease

BACKGROUND

Becoming shorter by each cell division, telomere length (TL) is regarded as a marker of cellular aging. Relative TL (T/S) depends on the quantitation of telomere hexamer repeat copy number normalized to autosomal single-copy gene copy number. TL is influenced by several factors, including oxidative stress (OS) and inflammation. This study aimed to investigate the possible role of TL and OS as markers for Alzheimer's disease (AD).

MATERIALS AND METHODS

One hundred and eighty participants were categorized into three groups. Group 1: Included 60 patients with AD. Group II: included 60 age-matched nondemented subjects. Group III (pregeriatric group): included 60 healthy controls with their ages ranging between 30 and 60 years. TL was determined by the quantitative Real time-PCR method, plasma levels of 8-OHdG by enzyme-linked immunosorbent assay, and total antioxidant capacity (TAC) by colorimetery.

RESULTS

In comparison to the other two groups, patients with AD showed shortened TL, increased plasma 8-OHdG concentration, and decreased TAC. The sensitivity of T/S ratio to predict AD was 86.67%, whereas the specificity was 96.67%. The sensitivity of 8-OHdG to predict AD was 96.67%, whereas the specificity was 86.67%.

CONCLUSION

AD is associated with shortened TL and increased OS as manifested by decreased TAC and increased serum 8-OHdG. T/S and 8-OHdG could be used as early predictors for AD.

Molecular Insight into the Therapeutic Promise of Targeting APOE4 for Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that causes chronic cognitive dysfunction. Most of the AD cases are late onset, and the apolipoprotein E (APOE) isoform is a key genetic risk factor. The APOE gene has 3 key alleles in humans including APOE2, APOE3, and APOE4. Among them, APOE4 is the most potent genetic risk factor for late-onset AD (LOAD), while APOE2 has a defensive effect. Research data suggest that APOE4 leads to the pathogenesis of AD through various processes such as accelerated beta-amyloid aggregations that raised neurofibrillary tangle formation, cerebrovascular diseases, aggravated neuroinflammation, and synaptic loss. However, the precise mode of actions regarding in what way APOE4 leads to AD pathology remains unclear. Since APOE contributes to several pathological pathways of AD, targeting APOE4 might serve as a promising strategy for the development of novel drugs to combat AD. In this review, we focus on the recent studies about APOE4-targeted therapeutic strategies that have been advanced in animal models and are being prepared for use in humans for the management of AD.