Decoding the heterogeneity of Alzheimer's disease diagnosis and progression using multilayer networks

The Relationship Between First Presenting Neuropsychiatric Symptoms in Older Adults and Autopsy-Confirmed Memory Disorders

OBJECTIVES

Although dementia is typically considered a disease of cognitive decline, almost all patients present with neuropsychiatric symptoms (NPS) at some stage of their disease. Few studies have assessed the timing of NPS onset in relation to pathological diagnoses of neurodegenerative diseases. We sought to examine the association between the first presenting clinically significant NPS in aging individuals and neuropathological diagnoses of memory disorders.

DESIGN

This retrospective longitudinal cohort study utilized the National Alzheimer's Coordinating Center (NACC) dataset, which includes participant data from 37 Alzheimer's Disease Research Centers collected between 2005 and 2022.

PARTICIPANTS

Participants (N = 5,416) aged 45 years or older with Clinical Dementia Rating-Global ratings of less than or equal to 1 were included in this analysis. A total of 4,033 (74.5%) participants presented with at least one NPS at any NACC visit.

MEASUREMENTS

To measure first NPS, the NACCBEHF variable was used, a clinician-rated variable defined as "the predominant symptom that was first recognized as a decline in the subject's behavior." Neuropathologic variables included assessments of Alzheimer's Disease, Frontotemporal Dementia, Lewy Body Dementia, Cerebral Amyloid Angiopathy, Hippocampal Sclerosis, and Cerebrovascular Disease.

RESULTS

Presentation with any clinically significant first NPS was associated with several neuropathological diagnoses including Alzheimer's Disease, Frontotemporal Lobar Dementia with TDP-43 pathology, and Lewy Body Dementia. While specific first NPS were associated with Frontotemporal Dementia neuropathology (personality change and disinhibition) and Lewy Body Dementia neuropathology (psychosis and REM behavior disturbance), Alzheimer's Disease neuropathology was associated with the majority of NPS.

CONCLUSIONS

Since neuropsychiatric symptoms are frequently the first presenting symptom of dementia, their associations with well-defined neuropathological diagnoses may help clinicians predict the subtype of future dementias.

Navigating the Frontiers of Machine Learning in Neurodegenerative Disease Therapeutics

Recent advances in machine learning hold tremendous potential for enhancing the way we develop new medicines. Over the years, machine learning has been adopted in nearly all facets of drug discovery, including patient stratification, lead discovery, biomarker development, and clinical trial design. In this review, we will discuss the latest developments linking machine learning and CNS drug discovery. While machine learning has aided our understanding of chronic diseases like Alzheimer's disease and Parkinson's disease, only modest effective therapies currently exist. We highlight promising new efforts led by academia and emerging biotech companies to leverage machine learning for exploring new therapies. These approaches aim to not only accelerate drug development but to improve the detection and treatment of neurodegenerative diseases.

MicroRNA (miRNA) Complexity in Alzheimer's Disease (AD)

AD is a complex, progressive, age-related neurodegenerative disorder representing the most common cause of senile dementia and neurological dysfunction in our elderly domestic population. The widely observed heterogeneity of AD is a reflection of the complexity of the AD process itself and the altered molecular-genetic mechanisms operating in the diseased human brain and CNS. One of the key players in this complex regulation of gene expression in human pathological neurobiology are microRNAs (miRNAs) that, through their actions, shape the transcriptome of brain cells that normally associate with very high rates of genetic activity, gene transcription and messenger RNA (mRNA) generation. The analysis of miRNA populations and the characterization of their abundance, speciation and complexity can further provide valuable clues to our molecular-genetic understanding of the AD process, especially in the sporadic forms of this common brain disorder. Current in-depth analyses of high-quality AD and age- and gender-matched control brain tissues are providing pathophysiological miRNA-based signatures of AD that can serve as a basis for expanding our mechanistic understanding of this disorder and the future design of miRNA- and related RNA-based therapeutics. This focused review will consolidate the findings from multiple laboratories as to which are the most abundant miRNA species, both free and exosome-bound in the human brain and CNS, which miRNA species appear to be the most prominently affected by the AD process and review recent developments and advancements in our understanding of the complexity of miRNA signaling in the hippocampal CA1 region of AD-affected brains.

The inhibition of ORMDL3 prevents Alzheimer's disease through ferroptosis by PERK/ATF4/HSPA5 pathway

Alzheimer's disease (AD) is a neurodegenerative disease with high incidence and widespread attention. There is currently no clear clarification of the pathogenesis. However, ORMDL3 causes ferroptosis in AD, and the potential mechanisms remain unclear. So, this study explore the function of ORMDL3 on ferroptosis in AD and its potential regulatory mechanisms. APPswe/PS1dE9 mice and C57BL/6 mice were induced into the mice model. The murine microglial BV-2 cells also were induced into the vitro model. In serum samples of AD patients, ORMDL3 mRNA expression levels were upregulated. The serum ORMDL3 levels expression was positively related to the ADL score or MoCA score in AD patients. The serum ORMDL3 expression level was positively related to MMSE score or Hcy levels in AD patients. The mRNA expression of ORMDL3 in the hippocampal tissue of the mice model of AD was upregulated at one, four and eight months. The protein expression of ORMDL3 was upregulated in the mice model of AD. ORMDL3 promoted Alzheimer's disease, and increased oxidative response and ferroptosis in a model of AD. PERK/ATF4/HSPA5 pathway is one important signal pathway for the effects of ORMDL3 in a model of AD. Collectively, these data suggested that ORMDL3 promoted oxidative response and ferroptosis in a model of AD by the PERK/ATF4/HSPA5 pathway, which might be a novel target spot mechanism of ferroptosis in AD and may serve as a regulator of AD-induced ferroptosis.