Introduction Blood‐based Alzheimer's disease (AD) biomarkers provide opportunities for community studies and across ethnic groups. We investigated blood biomarker concentrations in the Washington Heights‐Inwood Columbia Aging Project (WHICAP), a multi‐ethnic community study of aging and dementia. Methods We measured plasma amyloid beta (Aβ)40, Aβ42, total tau (t‐tau), phosphorylated tau (p‐tau)181, and p‐tau217, and neurofilament light chain (NfL) in 113 autopsied participants (29% with high AD neuropathological changes) and in 300 clinically evaluated individuals (42% with clinical AD). Receiver operating characteristics were used to evaluate each biomarker. We also investigated biomarkers as predictors of incident clinical AD. Results P‐tau181, p‐tau217, and NfL concentrations were elevated in pathologically and clinically diagnosed AD. Decreased Aβ42/Aβ40 ratio and increased p‐tau217 and p‐tau181 were associated with subsequent AD diagnosis. Discussion Blood‐based AD biomarker concentrations are associated with pathological and clinical diagnoses and can predict future development of clinical AD, providing evidence that they can be incorporated into multi‐ethnic, community‐based studies.

The import of acetyl-CoA into the ER lumen by AT-1/SLC33A1 is essential for the N -lysine acetylation of ER-resident and ER-transiting proteins. A point-mutation (S113R) in AT-1 has been associated with a familial form of spastic paraplegia. Here, we report that AT-1 S113R is unable to form homodimers in the ER membrane and is devoid of acetyl-CoA transport activity. The reduced influx of acetyl-CoA into the ER lumen results in reduced acetylation of ER proteins and an aberrant form of autophagy. Mice homozygous for the mutation display early developmental arrest. In contrast, heterozygous animals develop to full term, but display neurodegeneration and propensity to infections, inflammation, and cancer. The immune and cancer phenotypes are contingent on the presence of pathogens in the colony, whereas the nervous system phenotype is not. In conclusion, our results reveal a previously unknown aspect of acetyl-CoA metabolism that affects the immune and nervous systems and the risk for malignancies.

Introduction In Down syndrome (DS), the overproduction of amyloid precursor protein is hypothesized to predispose young adults to early expression of Alzheimer-like neuropathology. Methods PET imaging with [11C]PiB examined the pattern of amyloid-β deposition in 68 nondemented adults with DS (30-53 years) to determine the relationship between deposition and normal aging. Standard uptake value ratio (SUVR) images were created with cerebellum as the reference region. Results Multiple linear regression revealed slight but highly significant (corrected p<0.05) positive correlations between SUVR and age. The striatum showed the strongest correlation, followed by precuneus, parietal cortex, anterior cingulate, frontal cortex, and temporal cortex. Conclusion There is an age-related amyloid-β deposition in the DS population, but as a pattern of elevated cortical retention becomes apparent, the correlation of SUVR with age ceases to be significant. Factors unrelated to aging may drive an increase in deposition during early Alzheimer's disease pathogenesis.