Time-dependent impact of type 2 diabetes mellitus on incident prodromal Alzheimer disease: A longitudinal study in 1395 participants

Associations of ischemic heart disease with brain glymphatic MRI indices and risk of Alzheimer's disease

BACKGROUND

The impact of ischemic heart disease (IHD) on the brain glymphatic MRI indices and risk of Alzheimer's disease (AD) remains largely unclear. This study aimed to investigate the associations between IHD, brain glymphatic MRI indices and risk of AD.

METHODS

A total of 1385 non-dementia subjects (55.2 % male, mean age 73.53) were included. Diffusivity along the perivascular space (DTI-ALPS), free water (FW) and choroid plexus volume were used to reflect glymphatic function. The associations of IHD with MRI derived glymphatic indices, PET amyloid, tau and cognitive performance were explored by multiple regression analysis. IHD were tested as predictors of clinical progression using cox proportional hazards modeling. The mediation effect of MRI derived glymphatic indices on the relationship between IHD and cognitive changes was investigated.

RESULTS

Individuals with IHD exhibited glymphatic dysfunction revealed by lower DTI-ALPS (p = 0.035), higher FW (p < 0.001), and higher choroid plexus volume (p = 0.019). IHD had poorer cognitive performance in MMSE (p = 0.022), ADNI-MEM (p = 0.001) and ADNI-MF (p = 0.006), and more amyloid deposition (p = 0.007). IHD had a higher diagnostic conversion risk (HR = 1.321, 95 % CI = 1.003-1.741). IHD was associated with longitudinal cognitive decline in all cognitive tests (p < 0.05 for all) and FW (β = 0.012, 95 % CI 0.001, 0.023, p = 0.038). FW demonstrated an indirect effect (β = -0.0009, 95 % CI: -0.0034, -0.0001) and mediated 13.85 % effect for the relationship between IHD and ADNI-EF decline.

CONCLUSION

IHD is independently associated with AD risk, and brain glymphatic dysfunction may partially mediate this relationship.

Morphological, anatomical, and bioactive properties of Hypericum scabrum L.: effects on diabetes mellitus, Alzheimer's disease, and HDFa fibroblasts and U87-MG cancer cells

Diabetes mellitus (DM) and cancer are multifactorial diseases with significant health consequences, and their relationship with aging makes them particularly challenging. Epidemiological data suggests that individuals with DM are more susceptible to certain cancers. This study examined the bioactive properties of Hypericum scabrum extracts, including methanol, hexane, and others, focusing on their inhibitory effects on key enzymes associated with DM and neurodegenerative diseases, such as acetylcholinesterase, butyrylcholinesterase, α-amylase, and α-glucosidase. Additionally, the impact of these extracts on human fibroblast (HDFa) and glioblastoma (U87MG) cancer cells was evaluated. The methanol extract was analyzed for elemental composition using ICP-MS, secondary metabolites, and amino acids via LC-MS/MS and underwent morphological and anatomical characterization. The methanol extract demonstrated notable inhibitory activity, with an IC50 value of < 1 µg/mL against α-glucosidase, surpassing acarbose in efficacy. The flower essential oil exhibited the highest inhibition (79.95%) of butyrylcholinesterase and the strongest acetylcholinesterase inhibition (21.62%). Elemental analysis revealed high concentrations of Na and K, while quinic acid and proline were identified as major metabolites, with proline concentrations reaching 494.0482 nmol/mL in the aerial part extract. The anticancer assays revealed higher cytotoxicity in U87MG glioblastoma cells compared to HDFa fibroblasts, suggesting potential applications for cancer therapy. The plant grows 20-50 cm tall, with yellow flowers and ovoid-ribbed capsules containing brown, reniform seeds. Its leaves are amphistomatic and ornamented, while stems feature striate cuticles and paracytic stomata. The pollen grains are microreticulate with syncolporate apertures. These results underscore the promising therapeutic potential of H. scabrum in managing DM, cancer, and neurodegenerative diseases, with its ability to inhibit key enzymes and show selective cytotoxicity against cancer cells.

Unraveling the impact of blood RANKL and OPG levels on Alzheimer's disease: Independent of bone mineral density and inflammation

INTRODUCTION

Observational studies have revealed a close relationship between reduced bone mineral density (BMD) and Alzheimer's disease (AD) risk. The receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) system, pivotal in regulating bone metabolism, has been implicated in brain function, but the causal impact on AD risk remains unclear.

METHODS

We employed bi-directional Mendelian randomization (MR) and multivariable MR (MVMR) approaches to elucidate the effect of blood soluble RANKL (sRANKL) and OPG levels on AD, assessing whether this influence was independent of BMD and inflammation. Three distinct AD genome-wide association study (GWAS) data sets from the International Genomics of Alzheimer's Project (IGAP), UK Biobank (UKB), and FinnGen were utilized. Summary-level data on blood sRANKL and OPG were sourced from deCODE Genetics.

RESULTS

Genetically predicted per standard deviation (SD) increase in blood sRANKL levels was significantly associated with a reduced risk of AD across all three AD GWAS data sets (IGAP: odds ratio [OR] = 0.82, 95% confidence interval [CI] = 0.72-0.94, p = 0.004; UKB: OR = 0.85, 95% CI = 0.78-0.91, p < 0.001; FinnGen: OR = 0.83, 95% CI = 0.73-0.94, p = 0.004). No significant causal relationship was observed between OPG levels and AD. In addition, there was no causal impact of AD on the blood levels of sRANKL and OPG. MVMR results showed that the inverse association between sRANKL and AD risk persisted after adjusting for BMD and interleukin-1α and chemoattractant protein-1.

DISCUSSION

Our study provides evidence that elevated sRANKL levels are causally linked to a reduced risk of AD, independent of BMD and inflammation. These findings enhance our understanding of the complex interactions between bone metabolism and AD.

Highlights

Blood soluble receptor activator of nuclear factor kappa-B ligand (sRANKL) levels are linked to a reduced risk of Alzheimer's disease (AD).The association between sRANKL levels and AD is independent of bone mineral density (BMD) and inflammation.No causal link exists between blood osteoprotegerin levels and AD.AD does not affect blood levels of sRANKL or osteoprotegerin.

Differential gene expression analysis pipelines and bioinformatic tools for the identification of specific biomarkers: A review

In recent years, the role of bioinformatics and computational biology together with omics techniques and transcriptomics has gained tremendous importance in biomedicine and healthcare, particularly for the identification of biomarkers for precision medicine and drug discovery. Differential gene expression (DGE) analysis is one of the most used techniques for RNA-sequencing (RNA-seq) data analysis. This tool, which is typically used in various RNA-seq data processing applications, allows the identification of differentially expressed genes across two or more sample sets. Functional enrichment analyses can then be performed to annotate and contextualize the resulting gene lists. These studies provide valuable information about disease-causing biological processes and can help in identifying molecular targets for novel therapies. This review focuses on differential gene expression (DGE) analysis pipelines and bioinformatic techniques commonly used to identify specific biomarkers and discuss the advantages and disadvantages of these techniques.

Link Between Obsessive-Compulsive Disorder and ApoE Gene Polymorphisms

Objective

Many researchers have considered obsessive compulsive disorder (OCD) to be a neurodegenerative disease just like Alzheimer's disease (AD). The most studied gene in neurodegenerative diseases is apolipoprotein E (ApoE) gene, and ApoE ɛ4 allele in particular. Although a small number of studies have explored the relationship between ApoE gene polymorphisms and OCD, the link between age at onset of OCD, its subtypes and ApoE gene polymorphisms has not been revealed so far. For this purpose, in our study, the relationship of ApoE gene polymorphisms with age at onset of OCD and its subtypes has been investigated to reveal their neurodegenerative connections.

Patients and Methods

ApoE gene polymorphisms of 64 OCD and 28 healthy cases were studied using a LightCycler480 real-time PCR platform.

Results

A statistically significant difference was found between groups of patients with early- and late-onset OCD in terms of age (p = 0.03), educational level (p = 0.00) and marital status (p = 0.002). ApoE ɛ4ɛ4 genotype, the prevalence of which is below 2% in healthy individuals, was not detected in our control groups; however, it was identified in 5.1% of our OCD cases. Correlation analysis revealed the presence of a potentially significant link between the hoarding obsession and presence of the ɛ4ɛ4 genotype. A significant correlation was detected between the presence of the ɛ3ɛ3 allele, the symmetry obsession and associated ordering compulsion in patients with OCD (p<0.005).

Conclusion

The ApoE gene polymorphism profile and age of onset in OCD patients may play critical roles in the development process of neurodegenerative characteristics of the disease. The small number of cases and the inability to perform brain imaging in patients to detect the neurodegenerative link in OCD are limitations of our study. In this respect, we suggest conduction of further studies with a greater number of patients who will also undergo brain imaging studies. In addition, OCD patients have other genes associated with neurodegenerative diseases that can be screened.

Causal relationships between type 1 diabetes mellitus and Alzheimer's disease and Parkinson's disease: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Previous compelling evidence suggests an association between Type 2 diabetes (T2D) and neurodegenerative diseases. However, it remains uncertain whether Type 1 diabetes mellitus (T1DM) exerts a causal influence on the risk of Alzheimer's disease (AD) and Parkinson's disease (PD). Consequently, this study employed a bidirectional two-sample Mendelian Randomization (MR) approach to investigate the causal relationship between T1DM and the genetic susceptibility to AD and PD.

METHODS

We utilized large-scale cohorts derived from publicly available genome-wide association study datasets involving European populations to perform MR analyses. The primary analytical method employed was the inverse-variance weighted (IVW) approach. Furthermore, sensitivity analyses, including assessments of heterogeneity and horizontal pleiotropy, were carried out using Cochran's Q, MR-Egger intercept, and MR-PRESSO tests to enhance the robustness of our conclusions.

RESULTS

Using the IVW-based method, the MR analysis indicated no significant association between genetically determined T1DM and AD (OR = 0.984, 95% CI: 0.958-1.011, p = 0.247). Conversely, T1DM appeared to be associated with a reduced risk of genetic susceptibility to PD (IVW: OR = 0.958, 95% CI: 0.928-0.989, p = 0.001). In the reverse direction, no evidence of reverse causality was observed between AD (OR = 1.010, 95% CI: 0.911-1.116, p = 0.881) or PD (OR = 1.164, 95% CI: 0.686-2.025, p = 0.5202) and T1DM. Additionally, our analysis found no indications of the results being influenced by horizontal pleiotropy.

CONCLUSION

This MR study reveals that T1DM is associated with a reduced genetic susceptibility to PD, whereas no significant genetic susceptibility is observed between T1DM and AD. These findings suggest that T1DM may have a distinct role in the development of neurodegenerative diseases compared to T2D. Further investigations are warranted to elucidate the underlying mechanisms and provide a more comprehensive understanding of this relationship.

Assessing the Global, Regional, and National Impact of High Body Mass Index on Alzheimer's Disease and Other Dementias Between 1990 and 2019

BACKGROUND

Obesity significantly increases Alzheimer's disease (AD) and dementia risk. Understanding the link between a high body mass index (BMI) and these conditions is crucial for effective management and prevention.

OBJECTIVE

We aimed to estimate the burden of AD and other dementias attributed to high BMI from 1990 to 2019 based on sex, age, and socio-demographic indicators (SDI) at global, regional, and national levels.

METHODS

We collected data on deaths, disability-adjusted life years (DALYs), age-standardized mortality rates (ASMR), and age-standardized DALY rates (ASDR) from the 2019 Global Burden of Disease study for AD and dementia attributed to high BMI. We explored the correlation between SDI levels and ASDR.

RESULTS

In 2019, there were 198,476.2 deaths (95% UI: 32,695.4-593,366.4) and 3,159,912.4 DALYs (848,330.5-8,042,531) attributed to high BMI. Numbers of deaths, DALYs, ASMR, and ASDR increased since 1990. Females had higher deaths, ASMR, and ASDR than males. Mortality and DALYs rates increased with age. ASMR and ASDR increased across five SDI levels, with the highest rise in Low-middle SDI. High-income North America had the most deaths [30,993.9 (5,101.7-89,912.9)], while North Africa and the Middle East had the highest ASMR [4.61 (0.79-13.64)] and ASDR [72.56 (20.98-181.16)] in 2019.

CONCLUSIONS

The burden of AD and other dementias attributed to high BMI increased since 1990 globally and is still heaviest in developed regions. Females accounted predominantly for the burden than males. Timely measures are needed to against high BMI.