Impact of adrenal hormones, reproductive aging, and major depression on memory circuitry decline in early midlife

Metabolomics revealed that quercetin improved spleen metabolism disorders and regulated the brain-spleen axis in perimenopausal depression model rats

Perimenopausal depression is a subtype of depression that seriously harms women's health. The pathogenesis of perimenopausal depression remains unclear, which limits its prevention and therapy. Quercetin is a flavonoid with antidepressant and estrogen-like effects. This study aimed to explore the effects of quercetin on spleen metabolism in rats with perimenopausal depression and its potential mechanism. Untargeted metabolomics was employed to obtain splenic metabolite profiles, and 21 differential metabolites were identified. Pathway analysis revealed that glycerophospholipid metabolism, retinol metabolism, steroid hormone biosynthesis, and linoleic acid metabolism were disturbed. Notably, Spearman's rank correlation analysis revealed that differential metabolites were significantly correlated with behavioral test results (p < 0.01). After treatment with quercetin, the intensities of the above differential metabolites were restored (p < 0.01), indicating that quercetin can improve the spleen metabolic disorder induced by the perimenopausal depression model. Further study showed that quercetin can increase the expression of PPAR-α in the hippocampus and spleen, reduce the expression of NF-κB and the levels of TNF-α and IL-6 in the spleen, and restore the expression of CREB and BDNF in the hippocampus (p < 0.05 or p < 0.01). Our study is the first to explore the effect of quercetin on spleen metabolism disorders in perimenopausal depression model rats using untargeted metabolomics. Quercetin can improve spleen metabolism disorders through multiple pathways, which may be related to the restoration of hippocampal neuroplasticity and reduction of spleen inflammation by regulating the brain-spleen axis. Our study provides a potential strategy for preventing and treating perimenopausal depression.

Effects of Chaihu Shugan San on Brain Functional Network Connectivity in the Hippocampus of a Perimenopausal Depression Rat Model

In this study, we used Chaihu Shugan San (CSS), a traditional Chinese herbal formula, as a probe to investigate the involvement of brain functional network connectivity and hippocampus energy metabolism in perimenopausal depression. A network pharmacology approach was performed to discover the underlying mechanisms of CSS in improving perimenopausal depression, which were verified in perimenopausal depression rat models. Network pharmacology analysis indicated that complex mechanisms of energy metabolism, neurotransmitter metabolism, inflammation, and hormone metabolic processes were closely associated with the anti-depressive effects of CSS. Thus, the serum concentrations of estradiol (E2), glutamate (Glu), and 5-hydroxytryptamine (5-HT) were detected by ELISA. The brain functional network connectivity between the hippocampus and adjacent brain regions was evaluated using resting-state functional magnetic resonance imaging (fMRI). A targeted metabolomic analysis of the hippocampal tricarboxylic acid cycle was also performed to measure the changes in hippocampal energy metabolism using liquid chromatography-tandem mass spectrometry (LC-MS/MS). CSS treatment significantly improved the behavioral performance, decreased the serum Glu levels, and increased the serum 5-HT levels of PMS + CUMS rats. The brain functional connectivity between the hippocampus and other brain regions was significantly changed by PMS + CUMS processes but improved by CSS treatment. Moreover, among the metabolites in the hippocampal tricarboxylic acid cycle, the concentrations of citrate and the upregulation of isocitrate and downregulation of guanosine triphosphate (GTP) in PMS + CUMS rats could be significantly improved by CSS treatment. A brain functional network connectivity mechanism may be involved in perimenopausal depression, wherein the hippocampal tricarboxylic acid cycle plays a vital role.

Hypertension differentially impacts cognition in men and women in early midlife

The current study aimed to understand how sex differences in the timing of hypertension onset contribute to early midlife risk for cognitive decline that may differ by sex and whether sex-dependent advantages in normotensive populations are influenced by the presence of hypertension. One hundred and ninety-five adults aged 45-55 from the New England Family Study underwent neuropsychological testing to assess attention, executive function, and memory. Physician-diagnosed hypertension status was self-reported via questionnaire. Mid-adulthood hypertension was associated with worse performance on measures of attention and memory, but the cognitive domains impacted varied by sex. Hypertension was associated with only attention in men, whereas in women it was associated with attention and associative and working memory. Sex differences in midlife cognitive performance found in normotensive adults were attenuated in those with hypertension. Our results underscore the importance of accounting for sex when assessing the impact of hypertension on midlife cognition that could be indicative of later decline and risk for cognitive impairment and dementia, given hypertension is an independent risk factor.

Early exposure to wildfire smoke can lead to birth defects

The results of two previously published reports of the events and impacts of the Campfire wildfire smoke exposure that occurred in California in 2018 are amplified from the point of view of the potential toxic mechanism involved. The Campfire wildfire led to the exposure of a breeding colony of macaque monkeys (Macaca mulatta) during the peak of their breeding season in 2018-2019. Considering the timing, adverse effects, and endocrine implications reported, the cumulative evidence points to an early toxic sensitive period that can lead to birth defects in higher primates and human pregnancies. This deeper inspection of the published observations provides important caveats and useful guidance for future investigators. The unique higher primate placental-adrenal-brain axis may limit the use of many traditional toxicologic approaches. Retrospective neurological evaluations of human fetuses exposed to air pollutants during organogenesis and subsequent retrospective characterization of air samples using in vitro and animal models may be the best procedures to follow.

A Multilevel View of the Development of Alzheimer's Disease

Every year the Alzheimer's Association publishes a report that provides facts and figures indicating the public health, social and economic impact of Alzheimer's disease (AD). In addition, there are a number of reviews on the disease for general readers. Also, at congresses, AD is analyzed at different but not always related levels, leading to an "elephant as seen by blind men situation" for many of the participants. The review presented herein seeks to provide readers with a holistic view of how AD develops from various perspectives: the whole human organism, brain, circuits, neurons, cellular hallmarks, and molecular level.