Exploring the expression and potential function of follicle stimulating hormone receptor in extragonadal cells related to abdominal aortic aneurysm

INTRODUCTION

Follicle stimulating hormone (FSH) is identified to play a role in postmenopausal disease and hypothesized to affect abdominal aortic aneurysm (AAA) onset/progression in postmenopausal women. We aimed to detect FSHR gene expression in AAA tissue and cell types involved in AAA formation.

METHODS

FSH stimulation of human umbilical cord endothelial cells (HUVECs), smooth muscle cells (HUCs) and PMA-differentiated macrophages to assess gene expression of FSHR and various markers. Human macrophages activated with various stimuli were assessed for FSHR gene expression. AAA dataset, AAA tissue samples and AAA-derived smooth muscle cells (SMC) obtained from elderly female donors were assessed for FSHR gene expression. AAA-SMCs were stimulated with FSH to assess its effect on gene expression. Lastly, oxidized low-density-lipoprotein (ox-LDL) uptake and abundance of cell surface protein markers were assessed by flow cytometry after FSH stimulation of human monocytes.

RESULTS

FSH stimulation showed similar levels of gene expression in HUVECs and HUCs. Only ACTA2 was downregulated in HUCs. In PMA-differentiated macrophages, gene expression of inflammation markers was unchanged after FSH stimulation. FSHR gene expression was found to be low in the AAA datasets. Female AAA-SMCs show occasional FSHR gene expression at a very low level, yet stimulation with FSH did not affect gene expression of SMC- or inflammation markers. FSH stimulation did not impact ox-LDL uptake or alter cell surface protein expression in monocytes. While FSHR gene expression was detected in human testis tissue, it was below quantification level in all other investigated cell types, even upon activation of macrophages with various stimuli.

CONCLUSION

Despite previous reports, we did not detect FSHR gene expression in various extragonadal cell types, except in occasional female AAA-SMCs. No clear effect on cell activation was observed upon FSH stimulation in any cell type. Our data suggest that a direct effect of FSH in AAA-related extragonadal cells is unlikely to influence AAA.

Differences in Comorbidities Between Women and Men Treated with Elective Repair for Abdominal Aortic Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVES

Elective abdominal aortic aneurysm (AAA) repair is performed to prevent rupture. For reasons as yet unknown, the 30-day mortality risk after elective AAA repair is higher in women than in men. We hypothesised that this higher risk might be related to differences in comorbidity.

METHODS

Systematic review (PROSPERO CRD42019133314) according to PRISMA guidelines. A search in the EMBASE/MEDLINE/CENTRAL databases identified 1870 studies that included patients who underwent elective AAA repair (final search February 17^th, 2021). Ultimately, 28 studies were included and all reported comorbidities were categorised into 17 comorbidity groups. Additionally, 15 groups of clearly defined comorbidities were used for sensitivity analysis. For both groups, meta-analyses of each comorbidity were performed to estimate the difference in pooled prevalence between women and men with a random effects model.

RESULTS

When analysing data of all reported comorbidities (17 groups), smoking [risk difference (RD) 11%, 95% confidence interval (CI) 4-18], diabetes (RD 3%, 95% CI 2-4), ischaemic heart disease (RD 12%, 95% CI 8-16), arrhythmia (RD 3%, 95% CI 0.4-5), liver disease (RD 0.1%, 95% CI 0.01-0.2), and cancer (RD 3%, 95% CI 2-4)) were less prevalent in women, whereas, hypertension (RD 4%, 95% CI 3-6) and pulmonary disease (RD 4%, 95% CI 3-5) were more prevalent in women. At the time of surgery women were significantly older than men (74.9 years versus 72.4; mean difference 2.4 years (95% CI 2.1-2.7)). In the sensitivity analysis of 15 comorbidity groups, the same comorbidities remained significantly different between women and men, except smoking and arrhythmia. Women had a higher mortality risk than men (RD 1%, 95% CI 1-2).

CONCLUSIONS

Although women undergoing elective AAA repair have fewer baseline comorbidities than men, their 30-day mortality risk is higher. In-depth studies on the cause of death in women after elective AAA repair are needed to explain this discrepancy in mortality.