A Novel Hypothesis: A Role for Follicle Stimulating Hormone in Abdominal Aortic Aneurysm Development in Postmenopausal Women

Real World Sex Differences in Patients Undergoing Ascending Aortic Aneurysm Surgery-A Systematic Review and Meta-Analysis of Reconstructed Time-to-Event Data

Background: Men are known to have a higher incidence of acute cardiovascular events, while women are recognized for their increased mortality following diagnosis or intervention for these conditions. The aim of this study is to explore the sex differences in clinical profiles and outcomes of patients undergoing ascending aortic aneurysm (AscAA) surgery. Methods: A PRISMA compliant literature search and data extraction were conducted using PubMed, EMBASE, and SCOPUS. Observational cohort or retrospective registries that compared a defined number of male and female adults undergoing ascending aortic surgery for AscAA were included. Data analysis was conducted in compliance with Cochrane methods. Results: A total of 11 unique studies met the inclusion criteria, from which 13636 patients were included, with a distribution of 9124 males (67%) and 4512 females (33%). Overall, 91% underwent elective surgery. Male patients had significantly lower 30-day mortality, (RR: 0.68, 95% Cl [0.57, 0.81], p < 0.0001) and shorter stays in the intensive care unit, with a mean difference (MD) of -0.48 days ([-0.84, -0.13], p = 0.008). Males were significantly younger at the time of surgery (MD: -3.94 years, 95% CI [-5.58, -2.31], p < 0.00001). Male patients had significantly more frequent concomitant CABG (21% vs. 14.5%; p < 0.0001), while females had more frequent isolated supra-coronary ascending aortic replacement (22% vs. 36%; p = 0.004). Female patients who underwent AscAA surgery had significantly lower long-term survival (HR: 1.25, [1.05, 1.50], p = 0.013). Conclusions: Women undergo surgery for AscAA at older ages and face greater mortality. The disparities in preoperative age and timing of surgery between males and females can be explained by differences in comorbidity profiles and the need for concomitant surgery.

Hormonal influence: unraveling the impact of sex hormones on vascular smooth muscle cells

Sex hormones play a pivotal role as endocrine hormones that exert profound effects on the biological characteristics and vascular function of vascular smooth muscle cells (VSMCs). By modulating intracellular signaling pathways, activating nuclear receptors, and regulating gene expression, sex hormones intricately influence the morphology, function, and physiological state of VSMCs, thereby impacting the biological properties of vascular contraction, relaxation, and growth. Increasing evidence suggests that abnormal phenotypic changes in VSMCs contribute to the initiation of vascular diseases, including atherosclerosis. Therefore, understanding the factors governing phenotypic alterations in VSMCs and elucidating the underlying mechanisms can provide crucial insights for refining interventions targeted at vascular diseases. Additionally, the varying levels of different types of sex hormones in the human body, influenced by sex and age, may also affect the phenotypic conversion of VSMCs. This review aims to explore the influence of sex hormones on the phenotypic switching of VSMCs and the development of associated vascular diseases in the human body.

Sex-based disparities in ascending aortic aneurysm surgery outcomes: a comprehensive analysis of 1148 consecutive patients with propensity-score matching

BACKGROUND

Women undergoing cardiac surgery have been historically recognized to carry higher periprocedural mortality risk. We aimed to investigate the influence of sex on clinical presentation, perioperative, and long-term outcomes in patients who undergo surgery for ascending aortic aneurysm.

METHODS

We conducted a retrospective review of 1148 consecutive patients (380 [33.1%] female) who underwent thoracic aortic surgery under moderate hypothermic circulatory arrest for ascending aortic aneurysms between 2001 and 2021. Baseline and operative characteristics, in-hospital mortality, and survival were compared between male and female patients before and after propensity-score-matched (PSM) analysis.

RESULTS

Women were significantly older (median age: 69 [IQR: 63-75] vs. 67 [IQR: 58-73]; P < 0.001), while men had a higher prevalence of aortic valve stenosis, bicuspid valve and coronary artery disease at the time of surgery (P < 0.05). After PSM, EuroSCORE II (4.36 [2.68; 6.87] vs. 3.22 [1.85; 5.31]; p < 0.001), and indexed aortic diameter were significantly higher in female patients (2.94 [2.68; 3.30] vs. 2.58 [2.38; 2.81] cm/m2, p < 0.001). In the matched cohort, men were more likely to experience postoperative delirium (18.1% vs. 11.5%; P = 0.002), and postoperative neurological deficits (6.7% vs. 3.0%, P = 0.044),. Female patients were more likely to receive postoperative packed red blood cells (p = 0.036) and fresh frozen plasma (p = 0.049). In-hospital and 30-day mortality was similar between both groups. Long-term survival was comparable between both groups with 88% vs. 88% at 5 years, 76% vs. 71% at 10 years, and 59% vs. 47% at 15 years.

CONCLUSION

Female patients required more transfusions, while males had a higher incidence of postoperative delirium and neurological deficits. Differences in preoperative age and timing of surgery between the sexes could be attributed to variations in comorbidity profiles and the greater prevalence of concomitant surgery indications in males.

Follicle-stimulating hormone receptor expression in advanced atherosclerotic plaques

Experimental evidence indicates that follicle-stimulating hormone (FSH), an essential hormone for reproduction, can act directly on endothelial cells inducing atherosclerosis activation and development. However, it remains unknown whether the FSH-receptor (FSHR) is expressed in human atherosclerosis plaques. To demonstrate the FSHR presence, we used immunohistochemical and immunoelectron microscopy involving a specific monoclonal antibody FSHR1A02 that recognizes an epitope present in the FSHR-ectodomain. In all 55 patients with atherosclerotic plaques located in carotid, coronary, femoral arteries, and iliac aneurysm, FSHR was selectively expressed in arterial endothelium covering atherosclerotic plaques and endothelia lining intraplaque neovessels. Lymphatic neovessels were negative for FSHR. M1-macrophages, foam cells, and giant multinucleated cells were also FSHR-positive. FSHR was not detected in normal internal thoracic artery. Immunoelectron microscopy performed in ApoEKO/hFSHRKI mice with atherosclerotic plaques, after injection in vivo with mouse anti-hFSHR monoclonal antibody FSHR1A02 coupled to colloidal gold, showed FSHR presence on the luminal surface of arterial endothelial cells covering atherosclerotic plaques. Therefore, FSHR can bind, internalize, and deliver into the plaque circulating ligands to FSHR-positive cells. In conclusion, we report FSHR expression in endothelial cells, M1-macrophages, M1-derived foam cells, giant multinucleated macrophages, and osteoclasts associated with human atherosclerotic plaques.

Female-Specific Considerations in Aortic Health and Disease

The aorta plays a central role in the modulation of blood flow to supply end organs and to optimize the workload of the left ventricle. The constant interaction of the arterial wall with protective and deleterious circulating factors, and the cumulative exposure to ventriculoarterial pulsatile load, with its associated intimal-medial changes, are important players in the complex process of vascular aging. Vascular aging is also modulated by biomolecular processes such as oxidative stress, genomic instability, and cellular senescence. Concomitantly with well-established cardiometabolic and sex-specific risk factors and environmental stressors, arterial stiffness is associated with cardiovascular disease, which remains the leading cause of morbidity and mortality in women worldwide. Sexual dimorphisms in aortic health and disease are increasingly recognized and explain-at least in part-some of the observable sex differences in cardiovascular disease, which will be explored in this review. Specifically, we will discuss how biological sex affects arterial health and vascular aging and the implications this has for development of certain cardiovascular diseases uniquely or predominantly affecting women. We will then expand on sex differences in thoracic and abdominal aortic aneurysms, with special considerations for aortopathies in pregnancy.

Sex-Related Differences After Proximal Aortic Surgery: Outcome Analysis of 1773 Consecutive Patients

BACKGROUND

Guidelines on the management of aortic aneurysm disease do not account for sex differences regarding surgical procedures on the proximal aorta, although faster aneurysm growth, increased rupture risk, and higher postoperative mortality have been found in women. We therefore analyzed outcome differences between men and women receiving operations on the proximal aorta.

METHODS

A total of 1773 patients underwent nonemergency surgical procedures on the aortic valve (AV) and proximal aorta at our institution between 2000 and 2018. Of these, 772 patients (21.8% women) received a Bentall procedure, 349 (20.3% women) had AV-sparing root replacement, and 652 (31.1% women) underwent AV and supracommissural ascending aorta replacement. Primary outcomes were in-hospital mortality and midterm survival.

RESULTS

When assessing sex-related differences within the entire group of patients that received an operation on the proximal aorta, women were found to be older, had a lower body mass index, and were smokers less often. Despite shorter procedural times, median ventilation times and intensive care unit length of stay were longer in women. In-house mortality was also higher in women (3.6% vs 0.9%, P < .001). Multivariable logistic regression revealed age (odds ratio [OR], 1.8; 95% CI, 1.4-2.3 per 5 years added; P < .001), female sex (OR, 2.6; 95% CI, 1.2-5.8; P = .02), and urgent surgery (OR, 3.1; 95% CI, 1.2-7.3; P = .01) as independent risk factors for in-house death. Midterm survival was lower for women in the entire cohort (P = .02) and particularly within the Bentall subgroup (P = .004).

CONCLUSIONS

Female sex is an independent risk factor for operative mortality in patients undergoing proximal aortic surgery but is currently not addressed in guidelines. More research should focus on etiology and prevention of these worse outcomes in female patients.

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.

Double-edged sword of diabetes mellitus for abdominal aortic aneurysm

INTRODUCTION

Diabetes mellitus (DM) has been proved to contribute to multiple comorbidities that are risk factors for abdominal aortic aneurysm (AAA). Remarkably, evidences from epidemiologic studies have demonstrated a negative association between the two disease states. On the other hand, hyperglycemic state was linked to post-operative morbidities following AAA repair. This review aims to provide a thorough picture on the double-edged nature of DM and major hypoglycemic medications on prevalence, growth rate and rupture of AAA, as well as DM-associated prognosis post AAA repair.

METHODS

We performed a comprehensive search in electronic databases to look for literatures demonstrating the association between DM and AAA. The primary focus of the literature search was on the impact of DM on the morbidity, enlargement and rupture rate, as well as post-operative complications of AAA. The role of antidiabetic medications was also explored.

RESULTS

Retrospective epidemiological studies and large database researches associated the presence of DM with decreased prevalence, slower expansion and limited rupture rate of AAA. Major hypoglycemic drugs exert similar protective effect as DM against AAA by targeting pathological hallmarks involved in AAA formation and progression, which were demonstrated predominantly by animal studies. Nevertheless, presence of DM or postoperative hyperglycemia was linked to poorer short-term and long-term prognosis, primarily due to greater risk of infection, longer duration of hospital stays and death.

CONCLUSION

While DM is a positive factor in the formation and progression of AAA, it is also associated with higher risk of negative outcomes following AAA repair. Concomitant use of antidiabetic medications may contribute to the protective mechanism of DM in AAA, but further studies are still warranted to explore their role following AAA repair.