👤 S J Rabin

Depression and anxiety during pregnancy are major public health concerns with lasting consequences for mother and child. Although the gut microbiome contributes to stress and mood regulation, its role in preconceptional stress and transgenerational outcomes remains unclear. Here, we examined behavioral, microbial, and thalamic transcriptional effects of preconceptional social isolation rearing (SIR) in female mice and tested whether maternal probiotic supplementation mitigates these alterations. SIR females displayed increased anxiety-like and social-avoidant behavior, reduced gut microbial diversity, depletion of Odoribacter, Tuzzerella, and Alloprevotella, and enrichment of Bacteroides and Lachnospiraceae. A multispecies probiotic (Lactobacillus rhamnosus HN001, L. acidophilus La-14, Bifidobacterium lactis HN019) reversed these behavioral and microbial changes. Adult offspring of SIR dams showed sex-dependent behavioral deficits and microbial alterations partly reflecting maternal patterns. Prenatal SIR was associated with reduced thalamic Bdnf expression in offspring and altered Grin2a/2b selectively in males. In contrast, prenatal probiotic exposure exerted broader transcriptional effects and restored Bdnf levels in SIR offspring. SIR-induced increases in Lachnospiraceae were transmitted to offspring, whereas reductions in Ruminococcaceae were normalized by maternal probiotic treatment. Predicted functional profiling indicated sex-dependent modulation of microbial pathways related to tryptophan and central carbon metabolism. These findings demonstrate enduring transgenerational effects of preconceptional stress on the gut-brain axis and support maternal probiotic supplementation as a potential strategy to mitigate stress-induced dysregulation. Show less

Alzheimer's disease (AD) heterogeneity complicates early detection and trial design. Scalable predictors may aid risk stratification. We assessed whether scalable baseline plasma biomarkers and neuropsychological measures predict 5‑year cognitive and functional decline in cognitively unimpaired older adults. We analyzed 866 amyloid-positive participants from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) trial and 343 amyloid-negative individuals from the Longitudinal Evaluation of Amyloid Risk and Neurodegeneration (LEARN) study. Decline was defined as a ≥0.5 increase in Clinical Dementia Rating-Global Score over 240 weeks. The separate and joint value of demographics, apolipoprotein E ( The p-tau217 and PACC significantly improved prediction. Full models achieved areas under the curve (AUCs) of 0.78-0.80 across cohorts. Additional plasma biomarkers offered modest AUC gains (1%-3%). The p-tau217 and PACC enhanced prediction of preclinical decline, supporting their utility in early identification and trial enrichment in AD. Show less

People with mild cognitive impairment (MCI) are candidates for early intervention, but not all progress to Alzheimer's disease (AD) dementia. Identifying a subgroup at highest risk may improve treatment targeting. We analyzed data from participants with MCI enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI). Cognitive domains included memory, executive functioning, language, and visuospatial abilities. We evaluated baseline performance and 6-month change scores, using proportional hazards models to estimate associations with time to conversion to AD dementia. The strength of association varied by domain, but in general both baseline performance and 6-month change were associated with conversion. The strongest effects observed for memory and language. Observed associations were largely independent of established risk biomarkers, including APOE genotype, structural MRI measures, and CSF biomarkers. 6-month change scores on cognitive tests may help identify a high-risk subgroup of persons with MCI likely to progress to AD dementia. Systematic review. The authors reviewed the literature using traditional (e.g. PubMed) sources. There is a modest literature on change scores in the context of the AD clinical spectrum, but few investigations have evaluated whether short-term changes may be able to identify a high-risk subgroup of people with MCI. The authors have published a systematic review of this literature (Jutten et al. 2020) and appropriately refer to relevant citations here.Interpretation: Our findings suggest that short-term changes in cognition may be useful as part of a strategy to identify subsets of people with MCI who are at highest risk of conversion. Findings were clearest for memory and language. Domain-specific changes appeared to be independent from other biomarkers used to identify people at highest risk. Domain-specific changes did not appear to be better than changes in global cognition as measured by the MMSE or the CDR-sum of boxes.Future directions: Short-term changes in cognition may be useful to help identify a subgroup of people with MCI at highest risk of conversion to AD dementia. Future work could consider time frames shorter than the 6-month data we had available, better characterizing changes with more than 2 time points, or developing strategies that combine changes in cognition with other biomarkers to identify a subgroup of people with MCI to target for treatment. Show less

The objective of this study was to examine the expression and activation of the c-kit receptor, a specific receptor for kit ligand (stem cell factor, steel factor), in rat type A spermatogonia. Testes were obtained from 9-day-old rats, decapsulated, and then subjected to sequential enzymatic digestion. The mixture of testicular cell types was then separated by sedimentation velocity at unit gravity. The isolated type A spermatogonia were characterized by light and electron microscopy. They exhibited spherical nuclei containing several nucleoli and associated chromatin clumps and organelles generally in a perinuclear location similar to that found in the in vivo 9-day-old testis. The synthesis of the c-kit receptor by the spermatogonia was established by hybridization of total RNA with a specific cDNA for mouse c-kit receptor. Two mRNA transcripts migrating at 4.8 kb and 12 kb were observed. Localization of the c-kit receptor in the isolated cells was determined by immunocytochemistry using an antibody to c-kit protein. Specific staining for c-kit receptor was observed in the cytoplasm of the isolated type A spermatogonia. Furthermore, the presence of the c-kit receptor protein in the spermatogonia was confirmed by Western blot analysis using the same antibody. The antibody recognized the c-kit receptor at approximately 160 kDa. In an attempt to determine whether this receptor has a functional significance, we examined the effect of kit ligand on the phosphorylation of the c-kit receptor. The c-kit receptor appeared to be constitutively autophosphorylated on tyrosine at low basal levels, and upon stimulation with kit ligand, the amount of phosphorylated protein increased significantly. These observations indicate that kit ligand induces autophosphorylation of the c-kit receptor, which may lead to the activation of other cellular target proteins responsible for spermatogonial proliferation and/or differentiation. Show less