Sex, age and menopause differentially impact gut barrier function and proteomic profile

Abstract

Cardiovascular disease (CVD) and metabolic syndrome (MetS) depends on sex, age and hormonal status and is worsened by comprised gut barrier function. Previous work establishes that loss of estrogen and age comprises intestinal barrier function permeability exacerbating systemic inflammation, increasing gut oxidative stress, and elevating pro-inflammatory cytokines. We hypothesize that loss of estrogen during menopause underlies sex- and age-dependent pathological remodeling in gut barrier function leading to increased risk for CVD and MetS. C57BL-6 male and female mice were fed a high-fat-diet (HFD, 45% fat); menopause was induced via 21 days of 4-vinylcycohexane diepoxide (VCD) intraperitoneal injections (controls were injected with sesame oil) in adult and aged female mice. Diestrus was reached 14+days after the end of VCD injections and menopause was determined by cytology. Upon sacrifice, plasma was collected, and intestines were flash frozen. LPS assays were performed on plasma samples of premenopausal (n=8), menopausal (n=10), aged menopausal (n=6), and male mice (n=11). Male mice, and aged menopausal mice had significantly higher circulating endotoxin levels than premenopausal mice, while menopausal mice did not significantly differ from pre-menopause. These results indicate that age and sex impact barrier leakiness. Further, these results highlight that barrier integrity in menopause is distinctly different from aged menopause mice.Quantitative proteomics of ileum samples in premenopausal (n=5), menopausal (n=5), aged menopausal (n=5), and male mice (n=5) identified 7664 proteins with >1 unique peptide of which 134 proteins were significant (p<0.05) with a max fold change ˂1.27 across all groups. Protein expression of all groups was assessed using principal component analysis. Aged menopausal mice cluster closer to premenopausal mice than menopausal mice. These results indicate that changes in the ileum during menopause are different than those observed in aging. Compared to premenopausal mice, menopausal mice have significantly increased in proteins involved in the Go-biological processes including an enrichment in proteins involved in the innate immune system (6.3 fold enrichment, FE, -log10p=0.00006), phagocytosis recognition (19.82 FE, -log10p=1.14), defense response to bacterium (10.066 FE, -log10p=9.56), and B cell receptor signaling pathways (20.311 FE, -log10p=9.33). In contrast, male mice compared to premenopausal mice show a significant decrease in proteins involved in phagocytosis recognition (22.57 FE, -log10p=4.28), defense response to bacterium (12.898 FE, -log10p=2.76), and B cell receptor signaling pathway (20.56 FE, -log10p=8.12). These results indicate an increase in immune activity in menopausal female mice and a decrease in male mice compared to premenopausal female mice. In summary, these data demonstrate the change within the gut during menopause is dissimilar to those seen in male and aging mice. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.