Enodthelin 1 is elevated in plasma and explants from patients having uterine leiomyomas

Hypoxia in uterine fibroids: role in pathobiology and therapeutic opportunities

Uterine fibroids are the most common tumors in females affecting up to 70% of women world-wide, yet targeted therapeutic options are limited. Oxidative stress has recently surfaced as a key driver of fibroid pathogenesis and provides insights into hypoxia-induced cell transformation, extracellular matrix pathophysiology, hypoxic cell signaling cascades, and uterine biology. Hypoxia drives fibroid tumorigenesis through (1) promoting myometrial stem cell proliferation, (2) causing DNA damage propelling transformation of stem cells to tumor initiating cells, and (3) driving excess extracellular matrix (ECM) production. Common fibroid-associated DNA mutations include MED12 mutations, HMGA2 overexpression, and Fumarate hydratase loss of function. Evidence suggests an interaction between hypoxia signaling and these mutations. Fibroid development and growth are promoted by hypoxia-triggered cell signaling via various pathways including HIF-1, TGFβ, and Wnt/β-catenin. Fibroid-associated hypoxia persists due to antioxidant imbalance, ECM accumulation, and growth beyond adequate vascular supply. Current clinically available fibroid treatments do not take advantage of hypoxia-targeting therapies. Growing pre-clinical and clinical studies identify ROS inhibitors, anti-HIF-1 agents, Wnt/β-catenin inhibition, and TGFβ cascade inhibitors as agents that may reduce fibroid development and growth through targeting hypoxia.

Relationship Among Surgical Fibroid Removal, Blood Pressure, and Biomarkers of Renin-Angiotensin-Aldosterone System Activation

Fibroids are common benign neoplasms in women and have recently been associated with cardiometabolic risk factors including hypertension. The objective of this study is to determine whether fibroid removal is associated with lower blood pressure (BP). We performed a single-center IRB-approved retrospective chart review of patients undergoing hysterectomy/myomectomy for fibroids and other benign gynecological surgical procedures from January 2016 to December 2019, and a prospective cohort study of patients undergoing hysterectomy/myomectomy for fibroids from August 2021 to April 2022. We measured demographic factors, preoperative/postoperative BP on day of surgery and at postoperative visit. In our prospective cohort, to evaluate for alterations in the renin-angiotensin-aldosterone system (RAAS) induced by fibroid removal, we measured serum angiotensin-II (Ang-II) and angiotensin converting enzyme (ACE) levels pre- and post-operatively. In our retrospective study (n = 294; mean age 41.9 ± 10.6, 43.5% Black, 50% with fibroids), we found that compared to patients without fibroids, patients with fibroids had significantly elevated systolic BP (SBP) (pre-op: p = 0.0005; post-op: p = 0.02), although this did not hold after adjusting for covariates. Fibroid removal was associated with a marginally albeit not statistically significant decrease in SBP (p = 0.062). In our prospective study (n = 11), there was a significant decrease in SBP following fibroid removal, but no change in diastolic BP (p = 0.019, p = 0.18, respectively). Serum levels of Ang-II and ACE were not significantly altered following surgical fibroid removal (p = 0.72, p = 0.81, respectively). Altogether, these findings suggest that fibroids are not independently associated with BP or RAAS activation, but do suggest that fibroid removal may be associated with a small drop in SBP.

Pathways of Hypoxia-Inducible Factor (HIF) in the Orchestration of Uterine Fibroids Development

Uterine fibroids (UF) are common benign tumors in women. The course of UF is associated with troubling symptoms and the development of infertility and pregnancy pathology. Surgical treatment even implies hysterectomy, while pharmacological interventions are modestly effective. Classically, hypoxic metabolism is considered a hallmark of malignant tumor. However, the role of hypoxia-induced factor (HIF) is significant in benign tumors as well. Herein, we briefly review the basic biology of HIF-family proteins, outlining their possible roles in UF. Apart from theoretical justifications, we summarized 15 studies reporting increased expression of HIFs and downstream factors in UF samples. Altogether, data suggest that increased expression of the HIF-protein and altered expression of its dependent genes are presumed to be the factors leading to UF development. Thus, even without being a malignant tumor, UF is characterized by the strong involvement of HIF. This novel insight may give rise to further research in the direction of finding new prognostic markers and effective medicines against UF.

Uterine fibroids are associated with increased risk of pre-eclampsia: A case-control study

PURPOSE

Uterine fibroids are associated with hypertension in non-pregnant women. We aimed to evaluate the association between uterine fibroids and pre-eclampsia (PE).

PATIENTS AND METHODS

Participants were pregnant women who delivered in the Department of Obstetrics of the People's Hospital of Xinjiang Uygur Autonomous Region between January and December 2021. Patients with PE were identified as the case group, whereas those without PE were selected as the control group, using age-matching and a ratio of 1:5. Ultrasound examination during early pregnancy was used to detect uterine fibroids. Multivariable logistic regression was applied to evaluate the association between uterine fibroids and PE.

RESULTS

In total, 121 cases with PE and 578 controls without PE were included, with mean age of 32.9 years and gestational age of 37.7 weeks. Time of ultrasound examination was 12.0 ± 2.6 weeks. The case group had a significantly higher exposure rate of uterine fibroids than the control group (14.0 vs. 6.9%, P = 0.009). Multivariable Logistic regression models adjusted for potential confounding factors, including gestational age and blood pressure in early gestation, showed that pregnant women with uterine fibroids in early pregnancy exhibited three-fold higher odds for PE (OR, 3.02; 95% CI, 1.20-7.60; P = 0.019). Sensitivity analysis, which excluded those with gestational diabetes, further confirmed the robustness of the results. The association between uterine fibroids and PE was stronger in pregnant women aged ≥35 years and multiparas.

CONCLUSION

Uterine fibroids are significantly associated with an increased risk of PE in pregnant women. Uterine fibroids may serve as a new factor for identifying pregnant women at high risk of PE, and the effect of myomectomy before pregnancy on prevention of PE is worth further exploring.

Cardiometabolic profiles in women with adenomyosis

The aim of this study was to investigate the reproductive profiles, metabolic parameters and cardiometabolic risk assessed by surrogate indexes in women with adenomyosis. Ninety-six premenopausal women who were diagnosed with adenomyosis by transvaginal ultrasound and 97 age-body mass index (BMI) matched controls with normal ultrasound during routine examination were included. Women with adenomyosis were more likely to have higher gravidity and had more abortions than women without adenomyosis. Regarding the individual metabolic syndrome components, the adenomyosis group was more likely to have higher prevalence of hypertension, low HDL-C and central obesity. No significant difference was found between the groups in terms of visceral adiposity index, lipid accumulation product and fatty liver index. Only higher blood pressure (BP) remained statistically significant after adjustment for confounding factors in multivariate analysis. Women with adenomyosis had remarkably high risk of hypertension. It may be advisable to monitor their BP closely.Impact StatementWhat is already known on this subject? The only anthropometric characteristic assessed in women in relation to adenomyosis is body mass index (BMI). A case-control study showed that women who are obese are more likely to have adenomyosis. The gravidity, number of spontaneous abortions and previous uterine surgeries such as dilatation and curettage (D&C) and caesarean section were found significantly associated with adenomyosis.What do the results of this study add? A remarkable finding of our study was the increased incidence of higher systolic BP in women with adenomyosis. No difference was observed in adiposity indices between women with and without adenomyosis. Higher prevalence of central obesity and lower HDL-C levels were seen in women with adenomyosis.What are the implications of these findings for clinical practice and/or further research? The study identifies that adenomyosis is associated with an increased risk of hypertension, and women with adenomyosis may be monitored closely for blood pressure changes. Our report also provides novel information about the metabolic risk profiles associated with adenomyosis.

The relationship between muscle sympathetic nerve activity and systemic hemodynamics is altered in women with uterine fibroids

Women with uterine fibroids (UF), benign tumors of the myometrium, have a higher prevalence of hypertension than women without UF. The cause for this relationship is unclear. Muscle sympathetic nerve activity (MSNA) is a regulator of arterial blood pressure, and it is possible that variations in MSNA predispose women with UF to develop hypertension. The purpose of this study was to assess baseline blood pressure and MSNA and the relationships between MSNA and systemic hemodynamics in women with and without UF. We measured blood pressure (brachial intra-arterial line), MSNA (microneurography), and systemic hemodynamics (total peripheral resistance and cardiac output) at rest in 14 healthy, normotensive, premenopausal women with UF (42 ± 2 years old) and 9 healthy, normotensive, premenopausal women without UF (41 ± 2 years old). Baseline blood pressure and MSNA did not differ between groups (p > 0.05 for both). In women with UF, there was a positive correlation between MSNA and total peripheral resistance (r = 0.75, p = 0.02), as well as a negative correlation between MSNA and cardiac output (r = -0.73, p = 0.03). In contrast, these relationships were not seen in women without UF (p > 0.05 for both relationships). These data suggest that autonomic interactions with systemic hemodynamics, and thus blood pressure regulation, are different in healthy women with UF compared to healthy women without UF.

Association of uterine fibroids with increased blood pressure: a cross-sectional study and meta-analysis

Uterine fibroids (UFs) are the most common benign gynecological tumor and greatly affect reproductive health in women of reproductive age. Some studies have indicated an association between UFs and several cardiovascular disease (CVD) risk factors. To determine whether UFs are associated with increased blood pressure, we performed a cross-sectional study and meta-analysis. In the cross-sectional study, 8401 participants who underwent a physical examination at the First Affiliated Hospital of Shantou University Medical College from June 2011 to June 2013 were divided into a uterine fibroid group (1617 cases) and a control group (6784 cases) to assess the relationship between UFs and blood pressure. Then, we conducted a systematic review to confirm the results. The cross-sectional study showed that UFs were associated with an increased rate of elevated blood pressure [OR = 1.35, 95% confidence interval (CI): 1.016-1.792]. The meta-analysis revealed a significant association between UFs and the prevalence of hypertension [pooled OR = 1.44, 95% CI: 1.17-1.75, P = 0.0004; I² = 68%]. Thus, UFs may be associated with the prevalence of hypertension. Women with uterine fibroids should be closely monitored for hypertension.

Differential response to hypoxia in leiomyoma and myometrial cells

AIMS

Recent evidence suggests that repetitive hypoxia occurs during menstrual cycles due to vasoconstriction and myometrial contraction. It is unknown if hypoxia contributes to the development of uterine leiomyoma, the most common tumor of the female reproductive system. This study aims to characterize the response to hypoxia in leiomyoma and myometrial cells; and determine if an aberrant leiomyoma response to hypoxia may contribute to leiomyomatogenesis.

MAIN METHODS

Primary and immortalized leiomyoma and myometrial cells were cultured under normoxic and hypoxic conditions. Expression levels of vascular endothelial growth factor-A (VEGF-A), adrenomedullin (ADM), endothelin-1 (ET-1), and hypoxia-inducible factor-1 alpha (HIF-1α) were measured by qRT-PCR, western blotting and ELISA. Cell proliferation was assessed using MTT assay and proliferating-cell-nuclear-antigen (PCNA) expression. KC7F2 (HIF-1α inhibitor) was used to examine the regulating mechanisms.

KEY FINDINGS

As expected, hypoxia induced HIF-1α expression in both leiomyoma and myometrial cells. However, hypoxia induced VEGF-A, ET-1 and ADM expression and VEGF-A secretion into the culture media in leiomyoma but not myometrial cells. MTT assay and PCNA expression showed that hypoxia induces proliferation in leiomyoma, but not myometrial cells. HIF-1α inhibitor abrogated the hypoxia-induced VEGF-A, ET-1, ADM, and PCNA expression in leiomyoma cells.

SIGNIFICANCE

This study suggests an aberrant leiomyoma cellular response to hypoxia compared to myometrium. This differential response to menstruation-related repetitive hypoxia episodes may lead to selective proliferation of hypoxia-adaptive leiomyoma cells and contribute to leiomyoma growth. Thus, in addition to adding to our understanding of leiomyoma pathobiology, the study proposes angiogenic factors as a potential leiomyoma therapeutic target.

Vascular biology of uterine fibroids: connecting fibroids and vascular disorders

Fibroids are benign tumors caused by the proliferation of myometrial smooth muscle cells in the uterus that can lead to symptoms such as abdominal pain, constipation, urinary retention, and infertility. While traditionally thought of as a disease process intrinsic to the uterus, accumulating evidence suggests that fibroid growth may be linked with the systemic vasculature system, although cell-intrinsic factors are certainly of principal importance in their inception. Fibroids are associated with essential hypertension and preeclampsia, as well as atherosclerosis, for reasons that are becoming increasingly elucidated. Factors such as the renin-angiotensin-aldosterone system, estrogen, and endothelial dysfunction all likely play a role in fibroid pathogenesis. In this review, we lay out a framework for reconceptualizing fibroids as a systemic vascular disorder, and discuss how pharmaceutical agents and other interventions targeting the vasculature may aid in the novel treatment of fibroids.

Uterine fibroids increase the risk of hypertensive disorders of pregnancy: a prospective cohort study

OBJECTIVE

It is unclear whether uterine fibroids are associated with the occurrence of hypertensive disorders of pregnancy (HDP). Thus, this study aimed to evaluate the association between uterine fibroids and HDP in a prospective cohort.

METHODS

Overall, 2404 pregnant women who received antenatal care were enrolled in a prospective cohort in China between 2014 and 2016; 2277 women met the inclusion criteria of this study. The clinical characteristics of participants were assessed via questionnaires and physical examinations at baseline (before the 20th week of gestation), 21st-27th, 28th-34th, and 35th-39th gestational weeks. Ultrasound examination was performed before the 20th week of pregnancy to determine the presence of uterine fibroids. Linear mixed-effect and Cox proportional hazard regression models were used to analyze the association of uterine fibroids with blood pressure and HDP.

RESULTS

Of 2277 pregnant women, 242 (10.6%) had uterine fibroids, and 45 (2.0%) subsequently developed HDP. The incidence of HDP in women with and without uterine fibroids was 5% (n = 12) and 1.6% (n = 33), respectively. The longitudinal SBPs and DBPs were significantly higher in women with uterine fibroids than in those without. The multivariable Cox model showed that the presence of uterine fibroids was associated with increased HDP risk (adjusted hazard radio: 2.95, 95% confidence interval: 1.35-6.44).

CONCLUSION

Uterine fibroids in early pregnancy were associated with an increased HDP risk. Blood pressure of women with uterine fibroids should be closely monitored, and HDP preventive measures are crucial.

Novel treatment avenues for uterine leiomyoma: a new implication for endothelin?

Cysteine-rich angiogenic inducer 61 (CYR61), an angiogenic factor whose expression is decreased in fibroids. The aim of the present study was to determine if CYR61 secretion in smooth muscle cells (SMCs) is regulated by hypoxia and through the endothelin A (ETA) receptor. SMCs from fibroids (fSMC) and the adjacent myometrium smooth muscle cells (mSMCs) were extracted from ten women undergoing hysterectomy for uterine fibroids and cultured with or without 1.0 µM of an ETA receptor antagonist for 24 h under either normal or hypoxic oxygen conditions. Cellular secretion of endothelin-1 (ET-1) and CYR61 were measured via enzyme linked immunosorbent assay in the cell culture media. SMCs were collected to determine cell proliferation and CYR61 protein expression via Western blot. ET-1 secretion was significantly increased in fSMC and was decreased with blockade of the ETA receptor under both normoxia (P=0.0004) and hypoxia (P=0.008). CYR61 expression was decreased in fSMCs and significantly increased with blockade of the ETA receptor under hypoxia (P=0.04). Cell proliferation decreased with ETA blockade under normoxia (P=0.0001) and hypoxia (P=0.001). These results suggest that suppression of CYR61 secretion in fSMC is regulated by the ET-1 and that blockade with ETA could be considered for a future treatment option.

Tumor characterization by ultrasound-release of multiple protein and microRNA biomarkers, preclinical and clinical evidence

We have previously shown that low frequency ultrasound can release biomarkers from cells into the murine circulation enabling an amplification and localization of the released biomarker that could be used as a blood-based method to detect cancer earlier and monitor therapy. In this study, we further demonstrate that this technique could be used for characterization of tumors and/or identification of cellular masses of unknown origin due to the release of multiple protein and nucleic acid biomarkers in cells in culture, mice and patients. We sonicated colon (LS174T) and prostate (LNCaP) cancer cell lines in culture at a low frequency of 1 MHz and show that there were several-fold changes in multiple protein and microRNA (miRNA) abundance with treatment at various intensities and time. This release was dependent on the duration and intensity of the sonication for both cell lines. Significant increased release in biomarkers was also observed following tumor sonication in living mice bearing subcutaneous LS174T cell line xenografts (for proteins and nucleic acids) and in an experimental LS174T liver tumor model (for proteins only). Finally, we demonstrated this methodology of multiple biomarker release in patients undergoing ablation of uterine fibroids using MR guided high intensity focused ultrasound. Two protein biomarkers significantly increased in the plasma after the ultrasound treatment in 21 samples tested. This proof that ultrasound-amplification method works in soft tissue tumor models together with biomarker multiplexing, could allow for an effective non-invasive method for identification, characterization and localization of incidental lesions, cancer and other disease. Pre-treatment quantification of the biomarkers, allows for individualization of quantitative comparisons. This individualization of normal marker levels in this method allows for specificity of the biomarker-increase to each patient, tumor or organ being studied.

Molecular targets of dietary phytochemicals for possible prevention and therapy of uterine fibroids: Focus on fibrosis

Uterine fibroids (myomas or leiomyomas) are common benign tumors of reproductive aged women. Fibroids are clinically apparent in 20-50% of women, and cause abnormal uterine bleeding, abdominal pain and discomfort, pregnancy complications and infertility. Unfortunately, limited numbers of medical treatment are available but no effective preventive strategies exist. Moreover, the benefits of medical treatments are tempered by lack of efficacy or serious adverse side effects. Fibrosis has recently been recognized as a key pathological event in leiomyoma development and growth. It is defined by the excessive deposition of extracellular matrix (ECM). ECM plays important role in making bulk structure of leiomyoma, and ECM-rich rigid structure is believed to be a cause of abnormal bleeding and pelvic pain/pressure. Dietary phytochemicals are known to regulate fibrotic process in different biological systems, and being considered as potential tool to manage human health. At present, very few dietary phytochemicals have been studied in uterine leiomyoma, and they are mostly known for their antiproliferative effects. Therefore, in this review, our aim was to introduce some dietary phytochemicals that could target fibrotic processes in leiomyoma. Thus, this review could serve as useful resource to develop antifibrotic drugs for possible prevention and treatment of uterine fibroids.

Hypertension in an Animal Model of HELLP Syndrome is Associated With Activation of Endothelin 1

Women with hypertensive forms of pregnancy such as hemolysis-elevated liver enzymes-low platelet syndrome have increased circulating endothelin 1; however, the relationship between hypertension and endothelin 1 has not been studied. Using an animal model, we sought to determine whether there was an increased activation/dysfunction of endothelin 1, the effect of endothelin 1 receptor-A blockade on hypertension and other manifestations of hemolysis, elevated liver enzymes, and low platelets syndrome. On gestational day 12, timed-pregnant rats were infused with soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEndoglin; 4.7 and 7 µg/kg) via mini-osmotic pumps for 8 days. A subset of rats were treated with receptor-A antagonist (ABT-627, 5mg/kg) for 8 days. Rats with hemolysis-elevated liver enzymes-low platelet syndrome had significantly increased hypertension (P = .0001), circulating endothelin 1 (P = .03), and a significant 3.3- and 7.2-fold increase in preproendothelin messenger RNA (mRNA) expression in the placenta and liver (P = .01 and .04). Urinary protein:creatinine ratio was significantly increased in these animals (P = .0007), and circulating factors from these rats stimulated a significant increase in endothelial cell secretion of endothelin 1 (P = .001) in an in vitro assay. Blockade of the endothelin 1 receptor A significantly decreased hypertension (P = .001), circulating endothelin 1, and interleukin 17 (P = .004 and .003), placental preproendothelin mRNA expression (P = .016), and urinary protein:creatinine ratio (P = .007) in rats with hemolysis-elevated liver enzymes-low platelet syndrome. Blockade of the endothelin 1 receptor A significantly decreased hemolysis (P = .009), liver enzymes (P = .011), and significantly increased platelet levels (P = .03) and decreased circulating CD4+ and CD8+ T lymphocytes (P = .0004 and .0001) in rats infused with sFlt-1 and sEndoglin. These data support the hypothesis that endothelin 1 activation has a critical role in pathophysiology of as hemolysis-elevated liver enzymes-low platelet syndrome.