Parkinson Disease Neuropathological Comorbidities: Prevalences from Younger-Old to Older-Old, With Comparison to Non-Demented, Non-Parkinsonian Subjects.

Co-existing neuropathological comorbidities have been repeatedly reported to be extremely common in subjects dying with dementia due to Alzheimer disease. As these are likely to be additive to cognitive impairment, and may not be affected by molecularly-specific AD therapeutics, they may cause significant inter-individual response heterogeneity amongst subjects in AD clinical trials. Furthermore, while originally noted for the oldest old, recent reports have now documented high neuropathological comorbidity prevalences in younger old AD subjects, who are more likely to be included in clinical trials.

Distinct subcellular localization of tau and alpha-synuclein in lewy body disease.

Lewy bodies and neurofibrillary tangles, composed of α-synuclein (α-syn) and tau, respectively, often are found together in the same brain and correlate with worsening cognition. Human postmortem studies show colocalization of α-syn and tau occurs in Lewy bodies, but with limited effort to quantify colocalization. In this study, postmortem middle temporal gyrus tissue from decedents (n = 9) without temporal lobe disease (control) or with Lewy body disease (LBD) was immunofluorescently labeled with antibodies to phosphorylated α-syn (p-α-syn), tau phosphorylated at Ser202/Thr205 (p-tau), or exposure of tau's phosphatase-activating domain (PAD-tau) as a marker of early tau aggregates.

Comparative mapping of single-cell transcriptomic landscapes in neurodegenerative diseases.

Introduction: Alzheimer's disease (AD), Dementia with Lewy bodies (DLB), and Parkinson's disease (PD) represent a spectrum of neurodegenerative disorders (NDDs). Here, we performed the first direct comparison of their transcriptomic landscapes.

Methods: We profiled the whole transcriptomes of NDD cortical tissue by snRNA-seq.

Alzheimer's disease-associated CD83(+) microglia are linked with increased immunoglobulin G4 and human cytomegalovirus in the gut, vagal nerve, and brain.

Introduction: While there may be microbial contributions to Alzheimer's disease (AD), findings have been inconclusive. We recently reported an AD-associated CD83(+) microglia subtype associated with increased immunoglobulin G4 (IgG4) in the transverse colon (TC).

Methods: We used immunohistochemistry (IHC), IgG4 repertoire profiling, and brain organoid experiments to explore this association.

Comorbidities in early-onset sporadic versus presenilin-1 mutation-associated Alzheimer disease dementia: Evidence for dependency on Alzheimer disease neuropathological changes.

Studying comorbidities in early onset Alzheimer disease (AD) may provide an advantageous perspective on their pathogenesis because aging factors may be largely inoperative for these subjects. We compared AD comorbidities between early-onset sporadic cases and American and Colombian cases with PSEN1 mutations. AD neuropathological changes (ADNC) were very severe in all groups but more severe in the PSEN1 groups.