Clonality of smooth muscle and fibroblast cell populations isolated from human fibroid and myometrial tissues

Uterine fibroids at single-cell resolution: unveiling cellular heterogeneity to improve understanding of pathogenesis and guide future therapies

Uterine leiomyomas or fibroids are benign tumors of the myometrium that affect approximately 70% of reproductive-age women. Fibroids continue to be the leading cause of hysterectomy, resulting in substantial healthcare costs. Genetic complexity and lack of cellular and molecular understanding of fibroids have posed considerable challenges to developing noninvasive treatment options. Over the years, research efforts have intensified to unravel the genetic and cellular diversities within fibroids to deepen our understanding of their origins and progression. Studies using immunostaining and flow cytometry have revealed cellular heterogeneity within these tumors. A correlation has been observed between genetic mutations in fibroids and their size, which is influenced by cellular composition, proliferation rates, and extracellular matrix accumulation. Fibroids with mediator complex subunit 12 (MED12) mutation are composed of smooth muscle cells and fibroblasts equally. In contrast, the fibroids with high-mobility group AT-hook 2 (HMGA2) translocation are 90% composed of smooth muscle cells. More recently, single-cell RNA sequencing in the myometrium and MED12 mutation carrying fibroids has identified further heterogeneity in smooth muscle cells and fibroblast cells, identifying 3 different smooth muscle cell populations and fibroblast cell populations. Although both myometrium and fibroids have similar cellular composition, these cells differs in their transcriptomic profile and have specialized roles, underscoring the complex cellular landscape contributing to fibroid pathogenesis. Furthermore, not all smooth muscle cells in MED12-mutant fibroid carry the MED12 mutation, suggesting that MED12-mutant fibroids might not be monoclonal in nature. This review describes the intricacies of fibroid biology revealed by single-cell RNA sequencing. These advances have identified new cellular targets for potential therapies, provided insights into treatment resistance, and laid the groundwork for more personalized approaches to fibroid management. As we continue to unravel the cellular and molecular complexity of fibroids, we anticipate that this knowledge will translate into more effective and less invasive treatments, ultimately improving outcomes for the millions of women affected by this condition.

Utilising Human Myometrial and Uterine Fibroid Stem Cell-Derived Three Dimentional Organoids as a Robust Model System for Understanding the Pathophysiology of Uterine Fibroids

Uterine fibroids (UFs) are the most common benign gynecologic tumours affecting women of reproductive age. This study aims to deepen the understanding of UFs complex aetiology through harnessing the power of 3D organoid models derived from human myometrial stem cells to emulate the in vivo behaviour of these tumours. Isolated SCs were cultured over 7 days under a defined culture system. Immunohistochemistry, Immunofluorescence, organoid stiffness, RNA Sequencing was conducted, and differential gene expression was assessed using RT-PCR. The derived organoids exhibited diverse populations of cells, including stem cells, smooth muscle, and fibroblasts. Excessive ECM deposition was shown via Collagen and Fibronectin expression. We confirmed that our organoids expressed oestrogen receptor in a pattern similar to that in their corresponding tissue, as well as responded to steroid hormone. Interestingly, we revealed significant racial disparities in ECM accumulation within organoids derived from different racial groups. This augmented ECM deposition is theorised to enhance tissue stiffness, as assessed using Young's modulus. Additionally, our research demonstrated significant decreases in fibrotic markers upon treatment with Vitamin D3 and Doxercalciferol. Furthermore, the pro-fibroid effects of environmental phthalates further elucidate the potential factors contributing to UF pathology. The 3D organoid model can serve as a robust platform to study the underlying molecular mechanisms of UFs, besides offering invaluable insights for potential therapeutic interventions.

Evaluation of the In Vivo Efficacy of the JAK Inhibitor AZD1480 in Uterine Leiomyomas Using a Patient-derived Xenograft Murine Model

Uterine leiomyomas are common noncancerous hormonally-dependent neoplasms comprised of uterine smooth-muscle cells and fibroblasts. Despite their significant impact on morbidity, effective non-hormonal medical treatments are lacking. In vitro studies have identified the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway as a promising target in leiomyoma cells. Our objective was to evaluate the efficacy of AZD1480, a JAK 1/2 inhibitor, in treating uterine leiomyomas using a patient-derived xenograft murine model. Ovariectomized immunodeficient mice received an estrogen and progesterone pellet and were subsequently implanted with human leiomyoma tissue surgically resected from premenopausal women not on hormonal medication. Mice were divided into treatment (n = 6) and vehicle control (n = 6) groups receiving either 50 mg/kg of AZD1480 or vehicle via oral gavage for 5 days/week for 28 days. Our results demonstrate a significant AZD1480-mediated reduction in both xenograft volume (59.5% vs. 0.3%; treated vs. control, p < .0001) and weight (56.0% vs. 31.2%; p = 0.03) compared to controls. Moreover, xenografts from the treated group exhibited a significant decrease in cell density(p = 0.01). Levels of pSTAT3-positive cells (4.1% vs. 10.3%), Ki67-positive cells (4.1% vs. 6.5%), and fibrillar collagen (19.8% vs. 29.5%) declined but did not reach statistical significance, whereas AZD1480 treatment significantly reduced blood vessel formation in the xenografts (20.1 vs 45.6 per FOV; p = 0.01). These findings suggest JAK inhibition as a potential treatment for uterine leiomyomas by targeting angiogenesis. However, further studies are warranted to explore alternative JAK inhibitors, examine downstream effects, optimize dosing, and establish clinical efficacy and safety.

Proliferating cell nuclear antigen (PCNA) expression and serum IL-8 product in leiomyomas

BACKGROUND

The most prevalent neoplasms of the female genital tract are uterine leiomyomas, a uterine fibroid which rarely turn into cancer. We examined the levels of proliferating cell nuclear antigen (PCNA) and interleukin-8 (IL-8) in female patients with Leiomyomas.

METHODS

The presence of PCNA and IL-8 were measured in 28 females with Leiomyoma and 20 healthy controls. Tissue PCNA levels were measured by immunohistochemistry (IHC) method and serum IL-8 levels were measured by an ELISA technique. Age and menopausal stage on Leiomyoma development were also examined.

RESULTS

Forty-eight Iraqi women were divided into 28 uterine Leiomyoma patients of whom leiomyoma tissues, adjacent myometrium and serum samples were collected during hysterectomy. Serum samples were collected from 28 patients and 20 female controls. PCNA was positively expressed in 11 out of 28 (39.2 %) leiomyoma tissues; all 20 normal myometrium were negative. The presence of PCNA was unrelated to age and menopausal stage. The mean level of serum IL-8 was elevated significantly in patients (140 pg/ml) compared to that of control (60 pg/ml; P < 0.05). The IL -8 levels were increased in postmenopausal stage.

CONCLUSIONS

Each PCNA; IL-8 showed significantly elevated levels in patients with Leiomyoma.

Clinical and molecular risk factors for repeat interventions due to symptomatic uterine leiomyomas

BACKGROUND

Repeat leiomyoma occurrence or even reintervention is common after myomectomy. Little is known about the factors related to repeat interventions.

OBJECTIVE

This study aimed to determine the frequency of leiomyoma-related reintervention after an initial laparoscopic or abdominal myomectomy and to analyze both clinical and molecular risk factors for reinterventions. Another objective was to define the frequency of clonally related tumors from repeat operations.

STUDY DESIGN

This retrospective cohort study included 234 women who had undergone laparoscopic or abdominal myomectomy in 2009 to 2014. Information on repeat leiomyoma-related interventions as well as on other clinical factors was collected from medical records after a median follow-up time of 11.4 years (range 7.9-13.8 years) after the index procedure. The effect of clinical risk factors on the risk of reintervention was analyzed by the Kaplan-Meier estimator and the Cox proportional hazards model. For molecular analyses, we examined the mutation profiles of 133 formalin-fixed paraffin-embedded leiomyoma samples from 33 patients with repeat operations. We screened the tumors for the 3 primary leiomyoma driver alterations-mediator complex subunit 12 mutations, high mobility group AT-hook 2 overexpression, and fumarate hydratase-deficiency-utilizing Sanger sequencing and immunohistochemistry. To further assess the clonal relationship of the tumors, we executed whole-exome sequencing for 52 leiomyomas from 21 patients who exhibited the same driver alteration in tumors obtained from multiple procedures.

RESULTS

Reintervention rate at 11.4 years after myomectomy was 20% (46/234). Number of leiomyomas removed at the index myomectomy was a risk factor (hazard ratio 1.21; 95% confidence interval 1.09-1.34). Age at index myomectomy (hazard ratio 0.94; 95% confidence interval 0.89-0.99) and postoperative parity (hazard ratio 0.23; 95% confidence interval 0.09-0.60) were protective factors. Molecular characterization of tumors from index and nonindex operations confirmed a clonal relationship of the tumors in 3/33 (9%) patients. None of the leiomyomas harboring a mediator complex subunit 12 mutation-the most common leiomyoma driver-were confirmed clonally related. Fumarate hydratase-deficiency was detected in repeat leiomyomas from 3/33 (9%) patients. All these patients harbored a germline fumarate hydratase mutation, which is distinctive for the hereditary leiomyomatosis and renal cell cancer syndrome. Finally, we identified 3 (3/33; 9%) patients with 2 tumors each displaying somatic mutations in a recently identified novel leiomyoma driver gene, YEATS domain-containing protein 4. All YEATS domain-containing protein 4 mutations were different and thus the tumors were not clonally related.

CONCLUSION

Our study shows that reintervention is common after surgical myomectomy. Uterine leiomyomas typically develop independently, but some share a clonal origin. Repeat leiomyoma occurrence may be due to genetic predisposition, such as a germline fumarate hydratase mutation. Distinct somatic YEATS domain-containing protein 4 mutations identified in multiple leiomyomas from the same patient indicate a possible role for YEATS domain-containing protein 4 in repeat leiomyomas.

Relation of Endocan Serum Levels with Patient Characteristics and Morphological Features of Uterine Fibroids: A Case-Control Study

OBJECTIVES

This study aimed to compare the serum endocan levels of patients with uterine fibroids and the healthy control group.

DESIGN

A case-control study was designed. Participants/Materials: The study group includes women diagnosed with uterine fibroids, and the control group includes healthy women.

SETTING

The study was conducted at a tertiary education and research hospital with 130 women (uterine fibroid group, n = 65; control group, n = 65).

METHODS

Serum endocan levels were determined in the study and control groups using the ELISA method. The number of uterine fibroids was identified, and the volume of uterine fibroids was calculated with ellipsoid formula by ultrasonography. The primary outcome parameter was serum endocan levels in patients with uterine fibroids and healthy control groups. Second, it is aimed to determine the distribution of the serum endocan level of patients according to uterine fibroid number, volume, and clinical presentation.

RESULTS

The mean serum endocan level of patient with uterine fibroid was 145.18 ± 169.86 (median: 94.10; Q25-Q75%: 54.50-116.50) pg/mL; it was 88.94 ± 54.21 (median: 76.9; Q25-Q75%: 64.20-152.65) pg/mL in the control group (p = 0.016). According to ROC analysis, cutoff value of the endocan level for uterine fibroid was determined as ≥133.1 pg/mL. For the cutoff value of 133.1 pg/mL, sensitivity was 36.92%, specificity was 89.23%, positive predictive value was 77.40%, and negative predictive value was 58.60%. Above this cutoff value, a 4.8-fold increased significant risk (OR) for uterine fibroid was detected.

LIMITATIONS

The major limitation of the study is the lack of histopathological examination.

CONCLUSION

Serum endocan levels were found to be higher in women with uterine fibroids compared to the control group, so endocan may be considered as a significant serum marker.

Pilot Study on Boiling Histotripsy Treatment of Human Leiomyoma Ex Vivo

OBJECTIVE

As an alternative to surgical excision and magnetic resonance-guided thermal high-intensity focused ultrasound ablation of uterine leiomyoma, this work was aimed at pilot feasibility demonstration of use of ultrasound-guided boiling histotripsy for non-invasive non-thermal fractionation of human uterine leiomyoma ex vivo.

METHODS

A custom-made sector ultrasound transducer of 1.5-MHz operating frequency and nominal f-number F# = 0.75 was used to produce a volumetric lesion (two layers of 5 × 5 foci with a 1 mm step) in surgically resected human leiomyoma ex vivo. A sequence of 10 ms pulses (P+/P-/As = 157/-25/170 MPa in situ) with 1% duty cycle was delivered N = 30 times per focus under B-mode guidance. The treatment outcome was evaluated via B-mode imaging and histologically with hematoxylin and eosin and Masson's trichrome staining.

RESULTS

The treatment was successfully performed in less than 30 min and resulted in formation of a rectangular lesion visualized on B-mode images during the sonication as an echogenic region, which sustained for about 10 min post-treatment. Histology revealed loss of cellular structure, necrotic debris and globules of degenerated collagen in the target volume surrounded by injured smooth muscle cells.

CONCLUSION

The pilot experiment described here indicates that boiling histotripsy is feasible for non-invasive mechanical disintegration of human uterine leiomyoma ex vivo under B-mode guidance, encouraging further investigation and optimization of this potential clinical application of boiling histotripsy.

A 42-year-old woman with abnormal uterine bleeding-leiomyoma (AUB-L) reporting a hemoglobin of 1.6 g/dL: a case report

BACKGROUND

Abnormal uterine bleeding, formerly known as menometrorrhagia, is estimated to occur in up to one-third of women, commonly at menarche or perimenopause. Among many other causes, abnormal uterine bleeding is known to be caused by leiomyomas, and is itself a leading cause of severe iron deficiency and iron deficiency anemia in women. Rarely, abnormal uterine bleeding can lead to critically low hemoglobin values of less than 2 g/dL. We report here a case of a woman with abnormal uterine bleeding caused by leiomyomas presenting with severely low hemoglobin.

CASE PRESENTATION

We report the case of a 42-year-old Asian American woman who presented to the emergency department with chronic abnormal uterine bleeding and symptoms of anemia, including multiple syncopal episodes and abnormally pale skin but otherwise alert and oriented. Laboratory tests found a record-low hemoglobin of 1.6 g/dL and hematocrit of 6%. Transabdominal pelvic ultrasound revealed a lower uterine segment/cervical fibroid measuring 7.5 × 5 × 7.8 cm (length × depth × width). Patient was diagnosed with abnormal uterine bleeding-leiomyoma and received five units of packed red blood cells, one unit of fresh frozen plasma, Venofer infusions, tranexamic acid, and medroxyprogesterone. She was discharged from the hospital after 4 days.

CONCLUSION

To date, only a handful of cases have been reported of female patient survival following severely low hemoglobin caused by abnormal uterine bleeding. This case adds to this literature, highlighting the remarkable degree of compensation that can lead to an alert, ambulatory, and oriented patient with abnormal uterine bleeding caused by leiomyoma.

Serum Calcium and Magnesium Levels in Women with Uterine Fibroids in Southwest Nigeria: a Cross-sectional Study

Studies have suggested the potential roles of serum macronutrients such as calcium and magnesium in the development of uterine fibroids. The primary objective was to assess the association between serum magnesium and calcium levels and the prevalence of uterine fibroids in women of reproductive age. A cross-sectional study of 194 parity-matched women with or without a sonographic diagnosis of uterine fibroids enrolled at a university teaching hospital in Lagos, Southwest Nigeria. Participants' sociodemographic, ultrasound, and anthropometric information as well as the estimated serum levels of calcium and magnesium were collected for statistical analyses. This study found significant negative associations between low serum calcium levels and uterine fibroids (adjusted odds ratio = 0.06), uterine size, and the number of fibroid nodules. However, no significant association was observed between serum magnesium levels and uterine fibroids. This study found significant inverse associations between low serum calcium levels and uterine fibroids, uterine size, and the number of fibroid nodules.

Common Beverage Consumption and Benign Gynecological Conditions

The purpose of this article is to review the effects of four commonly consumed beverage types-sugar-sweetened beverages (SSBs), caffeinated beverages, green tea, and alcohol-on five common benign gynecological conditions: uterine fibroids, endometriosis, polycystic ovary syndrome (PCOS), anovulatory infertility, and primary dysmenorrhea (PD). Here we outline a plethora of research, highlighting studies that demonstrate possible associations between beverage intake and increased risk of certain gynecological conditions-such as SSBs and dysmenorrhea-as well as studies that demonstrate a possible protective effect of beverage against risk of gynecological condition-such as green tea and uterine fibroids. This review aims to help inform the diet choices of those with the aforementioned conditions and give those with uteruses autonomy over their lifestyle decisions.

Network-based drug repositioning of linagliptin as a potential agent for uterine fibroids targeting transforming growth factor-beta mediated fibrosis

Uterine fibroid is the most common non-cancerous tumor with no satisfactory options for long-term pharmacological treatment. Fibroblast activation protein-α (FAP) is one of the critical enzymes that enhances the fibrosis in uterine fibroids. Through STITCH database mining, we found that dipeptidyl peptidase-4 inhibitors (DPP4i) have the potential to inhibit the activity of FAP. Both DPP4 and FAP belong to the dipeptidyl peptidase family and share a similar catalytic domain. Hence, ligands which have a binding affinity with DPP4 could also bind with FAP. Among the DPP4i, linagliptin exhibited the highest binding affinity (Dock score = -8.562 kcal/mol) with FAP. Our study uncovered that the differences in the S2 extensive-subsite residues between DPP4 and FAP could serve as a basis for designing selective inhibitors specifically targeting FAP. Furthermore, in a dynamic environment, linagliptin was able to destabilize the dimerization interface of FAP, resulting in potential inhibition of its biological activity. True to the in-silico results, linagliptin reduced the fibrotic process in estrogen and progesterone-induced fibrosis in rat uterus. Furthermore, linagliptin reduced the gene expression of transforming growth factor-β (TGF-β), a critical factor in collagen secretion and fibrotic process. Masson trichrome staining confirmed that the anti-fibrotic effects of linagliptin were due to its ability to reduce collagen deposition in rat uterus. Altogether, our research proposes that linagliptin has the potential to be repurposed for the treatment of uterine fibroids.

Cysteine-rich intestinal protein 1 is a novel surface marker for human myometrial stem/progenitor cells

Myometrial stem/progenitor cells (MyoSPCs) have been proposed as the cells of origin for uterine fibroids, but the identity of the MyoSPC has not been well established. We previously identified SUSD2 as a possible MyoSPC marker, but the relatively poor enrichment in stem cell characteristics of SUSD2+ over SUSD2- cells compelled us to find better markers. We combined bulk RNA-seq of SUSD2+/- cells with single cell RNA-seq to identify markers for MyoSPCs. We observed seven distinct cell clusters within the myometrium, with the vascular myocyte cluster most highly enriched for MyoSPC characteristics and markers. CRIP1 expression was found highly upregulated by both techniques and was used as a marker to sort CRIP1+/PECAM1- cells that were both enriched for colony forming potential and able to differentiate into mesenchymal lineages, suggesting that CRIP1+/PECAM1- cells could be used to better study the etiology of uterine fibroids.

Serum Calcium and Magnesium Levels in Women with Uterine Fibroids at a University Teaching Hospital in Southwest Nigeria: A Comparative Cross-Sectional Study

Background: Studies have suggested the potential roles of serum trace elements such as calcium and magnesium in the development of uterine fibroids. Aims: This study compared magnesium and calcium serum levels in reproductive-age women with and without uterine fibroids in Lagos, Southwest Nigeria. Methods: A comparative cross-sectional study of 194 parity-matched women with or without a sonographic diagnosis of uterine fibroids enrolled at a university teaching hospital in Lagos, Southwest Nigeria. Participants' sociodemographic, ultrasound, and anthropometric information as well as the estimated serum levels of calcium and magnesium were collected for statistical analyses. Results: This study found significant negative associations between low serum calcium levels and uterine fibroids (adjusted odds ratio= 0.06; 95% CI: 0.004, 0.958; p=0.047), uterine size (p=0.004), and the number of fibroid nodules (p=0.030). However, no significant association was observed between serum magnesium levels and uterine fibroids (p=0.341). Conclusion: The findings of this study suggest the promising role of calcium-rich diets and supplements in the prevention of uterine fibroids among Nigerian women. However, future longitudinal studies are required to further evaluate the potential role of these trace mineral elements in the development of uterine fibroids.

Cysteine-Rich Intestinal Protein 1 is a Novel Surface Marker for Myometrial Stem/Progenitor Cells

Myometrial stem/progenitor cells (MyoSPCs) have been proposed as the cells of origin for uterine fibroids, which are benign tumors that develop in the myometrium of most reproductive age women, but the identity of the MyoSPC has not been well established. We previously identified SUSD2 as a possible MyoSPC marker, but the relatively poor enrichment in stem cell characteristics of SUSD2+ over SUSD2- cells compelled us to find better discerning markers for more rigorous downstream analyses. We combined bulk RNA-seq of SUSD2+/- cells with single cell RNA-seq to identify markers capable of further enriching for MyoSPCs. We observed seven distinct cell clusters within the myometrium, with the vascular myocyte cluster most highly enriched for MyoSPC characteristics and markers, including SUSD2. CRIP1 expression was found highly upregulated in both techniques and was used as a marker to sort CRIP1+/PECAM1- cells that were both enriched for colony forming potential and able to differentiate into mesenchymal lineages, suggesting that CRIP1+/PECAM1- cells could be used to better study the etiology of uterine fibroids.

Update on the Role and Regulatory Mechanism of Extracellular Matrix in the Pathogenesis of Uterine Fibroids

Uterine fibroids (UFs), also known as leiomyomas, are benign tumors of the myometrium affecting over 70% of women worldwide, particularly women of color. Although benign, UFs are associated with significant morbidity; they are the primary indication for hysterectomy and a major source of gynecologic and reproductive dysfunction, ranging from menorrhagia and pelvic pain to infertility, recurrent miscarriage, and preterm labor. So far, the molecular mechanisms underlying the pathogenesis of UFs are still quite limited. A knowledge gap needs to be filled to help develop novel strategies that will ultimately facilitate the development of therapies and improve UF patient outcomes. Excessive ECM accumulation and aberrant remodeling are crucial for fibrotic diseases and excessive ECM deposition is the central characteristics of UFs. This review summarizes the recent progress of ascertaining the biological functions and regulatory mechanisms in UFs, from the perspective of factors regulating ECM production, ECM-mediated signaling, and pharmacological drugs targeting ECM accumulation. In addition, we provide the current state of knowledge by discussing the molecular mechanisms underlying the regulation and emerging role of the extracellular matrix in the pathogenesis of UFs and in applications. Comprehensive and deeper insights into ECM-mediated alterations and interactions in cellular events will help develop novel strategies to treat patients with this common tumor.

A View on Uterine Leiomyoma Genesis through the Prism of Genetic, Epigenetic and Cellular Heterogeneity

Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology. In this review, we comprehensively analyse risk and protective factors for UL development, UL cellular composition, hormonal and paracrine signalling, epigenetic regulation and genetic abnormalities. We conclude the need to carefully update the concept of UL genesis in light of the current data. Staying within the framework of the existing hypotheses, we introduce a possible timeline for UL development and the associated key events—from potential prerequisites to the beginning of UL formation and the onset of driver and passenger changes.

Green Tea and Benign Gynecologic Disorders: A New Trick for An Old Beverage?

Green tea is harvested from the tea plant Camellia sinensis and is one of the most widely consumed beverages worldwide. It is richer in antioxidants than other forms of tea and has a uniquely high content of polyphenolic compounds known as catechins. Epigallocatechin-3-gallate (EGCG), the major green tea catechin, has been studied for its potential therapeutic role in many disease contexts, including pathologies of the female reproductive system. As both a prooxidant and antioxidant, EGCG can modulate many cellular pathways important to disease pathogenesis and thus has clinical benefits. This review provides a synopsis of the current knowledge on the beneficial effects of green tea in benign gynecological disorders. Green tea alleviates symptom severity in uterine fibroids and improves endometriosis through anti-fibrotic, anti-angiogenic, and pro-apoptotic mechanisms. Additionally, it can reduce uterine contractility and improve the generalized hyperalgesia associated with dysmenorrhea and adenomyosis. Although its role in infertility is controversial, EGCG can be used as a symptomatic treatment for menopause, where it decreases weight gain and osteoporosis, as well as for polycystic ovary syndrome (PCOS).

Biomechanical Forces Determine Fibroid Stem Cell Transformation and the Receptivity Status of the Endometrium: A Critical Appraisal

Myometrium cells are an important reproductive niche in which cyclic mechanical forces of a pico-newton range are produced continuously at millisecond and second intervals. Overproduction and/or underproduction of micro-forces, due to point or epigenetic mutation, aberrant methylation, and abnormal response to hypoxia, may lead to the transformation of fibroid stem cells into fibroid-initiating stem cells. Fibroids are tumors with a high modulus of stiffness disturbing the critical homeostasis of the myometrium and they may cause unfavorable and strong mechanical forces. Micro-mechanical forces and soluble-chemical signals play a critical role in transcriptional and translational processes' maintenance, by regulating communication between the cell nucleus and its organelles. Signals coming from the external environment can stimulate cells in the format of both soluble biochemical signals and mechanical ones. The shape of the cell and the plasma membrane have a significant character in sensing electro-chemical signals, through specialized receptors and generating responses, accordingly. In order for mechanical signals to be perceived by the cell, they must be converted into biological stimuli, through a process called mechanotransduction. Transmission of fibroid-derived mechanical signals to the endometrium and their effects on receptivity modulators are mediated through a pathway known as solid-state signaling. It is not sufficiently clear which type of receptors and mechanical signals impair endometrial receptivity. However, it is known that biomechanical signals reaching the endometrium affect epithelial sodium channels, lysophosphatidic acid receptors or Rho GTPases, leading to conformational changes in endometrial proteins. Translational changes in receptivity modulators may disrupt the selectivity and receptivity functions of the endometrium, resulting in failed implantation or early pregnancy loss. By hypermethylation of the receptivity genes, micro-forces can also negatively affect decidualization and implantation. The purpose of this narrative review is to summarize the state of the art of the biomechanical forces which can determine fibroid stem cell transformation and, thus, affect the receptivity status of the endometrium with regard to fertilization and pregnancy.

Single-cell sequencing reveals novel cellular heterogeneity in uterine leiomyomas

STUDY QUESTION

What are the cellular composition and single-cell transcriptomic differences between myometrium and leiomyomas as defined by single-cell RNA sequencing?

SUMMARY ANSWER

We discovered cellular heterogeneity in smooth muscle cells (SMCs), fibroblast and endothelial cell populations in both myometrium and leiomyoma tissues.

WHAT IS KNOWN ALREADY

Previous studies have shown the presence of SMCs, fibroblasts, endothelial cells and immune cells in myometrium and leiomyomas. However, there is no information on the cellular heterogeneity in these tissues and the transcriptomic differences at the single-cell level between these tissues.

STUDY DESIGN, SIZE, DURATION

We collected five leiomyoma and five myometrium samples from a total of eight patients undergoing hysterectomy. We then performed single-cell RNA sequencing to generate a cell atlas for both tissues. We utilized our single-cell sequencing data to define cell types, compare cell types by tissue type (leiomyoma versus myometrium) and determine the transcriptional changes at a single-cell resolution between leiomyomas and myometrium. Additionally, we performed MED12-variant analysis at the single-cell level to determine the genotype heterogeneity within leiomyomas.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We collected five MED12-variant positive leiomyomas and five myometrium samples from a total of eight patients. We then performed single-cell RNA sequencing on freshly isolated single-cell preparations. Histopathological assessment confirmed the identity of the samples. Sanger sequencing was performed to confirm the presence of the MED12 variant in leiomyomas.

MAIN RESULTS AND ROLE OF CHANCE

Our data revealed previously unknown heterogeneity in the SMC, fibroblast cell and endothelial cell populations of myometrium and leiomyomas. We discovered the presence of two different lymphatic endothelial cell populations specific to uterine leiomyomas. We showed that both myometrium and MED12-variant leiomyomas are relatively similar in cellular composition but differ in cellular transcriptomic profiles. We found that fibroblasts influence the leiomyoma microenvironment through their interactions with endothelial cells, immune cells and SMCs. Variant analysis at the single-cell level revealed the presence of both MED12 variants as well as the wild-type MED12 allele in SMCs of leiomyomatous tissue. These results indicate genotype heterogeneity of cellular composition within leiomyomas.

LARGE SCALE DATA

The datasets are available in the NCBI Gene Expression Omnibus (GEO) using GSE162122.

LIMITATIONS, REASONS FOR CAUTION

Our study focused on MED12-variant positive leiomyomas for single-cell RNA sequencing analyses. Leiomyomas carrying other genetic rearrangements may differ in their cellular composition and transcriptomic profiles.

WIDER IMPLICATIONS FOR THE FINDINGS

Our study provides a cellular atlas for myometrium and MED12-variant positive leiomyomas as defined by single-cell RNA sequencing. Our analysis provides significant insight into the differences between myometrium and leiomyomas at the single-cell level and reveals hitherto unknown genetic heterogeneity in multiple cell types within human leiomyomas. Our results will be important for future studies into the origin and growth of human leiomyomas.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by funding from the National Institute of Child Health and Human Development (HD098580 and HD088629). The authors declare no competing interests.

Epidemiology of uterine fibroid in black African women: a systematic scoping review

OBJECTIVE

Studies, mainly from high-income countries, suggest that there are ethnic and racial variations in prevalence of uterine fibroids (UF). However, there have been few studies of the epidemiology of UF in sub-Saharan Africa (SSA). We reviewed published articles on the epidemiology of UF in SSA.

DESIGN

This was a scoping review of literature.

SETTINGS

We searched three databases (PubMed, African Wide Information (EBSCO) and African Journals OnLine (AJOL)). The search for eligible articles was conducted between December 2019 and January 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

To describe the reported prevalence/incidence of, and risk factors for UF in SSA.

RESULTS

Of the 1052 articles retrieved, 9 met the inclusion criteria for review. The articles were from Nigeria (4/9), Ghana (2/9), Cameroon (1/9), Kenya (1/9) and South Africa (1/9). Two studies from pathology departments and three studies from radiology departments reported prevalence of UF. We did not find any study on the incidence or genomics of UF in SSA. Of the three studies that reported on the risk factors of UF, only one case-control study that was conducted using retrospective data of attendees at a gynaecological clinic conducted multivariable analysis.

CONCLUSION

There is lack of robust epidemiological studies of the prevalence, incidence and risk factors of UF in SSA. There is urgent need to study epidemiological and genomics risk factors of UF in SSA because UF is the most common gynaecological neoplasm in this population where it is associated with significant morbidity and occasional, usually perioperative, mortality.

Comprehensive Review of Uterine Fibroids: Developmental Origin, Pathogenesis, and Treatment

Uterine fibroids are benign monoclonal neoplasms of the myometrium, representing the most common tumors in women worldwide. To date, no long-term or noninvasive treatment option exists for hormone-dependent uterine fibroids, due to the limited knowledge about the molecular mechanisms underlying the initiation and development of uterine fibroids. This paper comprehensively summarizes the recent research advances on uterine fibroids, focusing on risk factors, development origin, pathogenetic mechanisms, and treatment options. Additionally, we describe the current treatment interventions for uterine fibroids. Finally, future perspectives on uterine fibroids studies are summarized. Deeper mechanistic insights into tumor etiology and the complexity of uterine fibroids can contribute to the progress of newer targeted therapies.

Human Myometrial and Uterine Fibroid Stem Cell-Derived Organoids for Intervening the Pathophysiology of Uterine Fibroid

Uterine fibroids (UFs) (leiomyomas or myomas) are the most common clonal neoplasms of the uterus in women of reproductive age worldwide. UFs originate from myometrium consist of smooth muscle and fibroblast components, in addition to a substantial amount of fibrous extracellular matrix which all contribute to the pathogenetic process. Current treatments are primarily limited to surgical and interventional. Here, we have established a novel and promising organoid model from both normal and patient myometrial stem cells (MMSCs). MMSCs embedded in Matrigel in stem cell media swiftly formed organoids which successfully proliferate and self-organized into complex structures developing a sustainable organoid culture that maintain their capacity to differentiate into the different cell types recapitulating their tissue of origin and shows responsiveness to the reproductive hormones (estrogen and progesterone). Gene expression analysis and structural features indicated the early onset of uterine fibrosis led to the accumulation of extracellular matrix suggesting the potential use of this model in better understanding of the pathophysiology associated with UFs and inventing novel therapeutics for the treatment of UFs.

Familial Predisposition to Leiomyomata: Searching for Protective Genetic Factors

In order to determine genetic loci associated with decreasing risk of uterine leiomyomata (UL), a genome-wide association study (GWAS) was performed. We analyzed a group of patients with a family history of UL and a control group consisting of patients without uterine fibroids and a family predisposition to this pathology. Six significant single nucleotide polymorphisms were selected for PCR-genotyping of a large data set of patients with UL. All investigated loci (rs3020434, rs11742635, rs124577644, rs12637801, rs2861221, and rs17677069) demonstrated the lower frequency of minor alleles within a group of women with UL, especially in a subgroup consisting of patients with UL and a familial history of leiomyomata. We also found that the minor allele frequencies of these SNPs in our control group were higher than those across the Caucasian population in all. Based on the obtained data, an evaluation of the common risk of UL was performed. Further work will pave the way to create a specific SNP-panel and allow us to estimate a genotype-based leiomyoma incidence risk. Subsequent studies of genetic variability in a group of patients with a familial predisposition to UL will allow us to make the prediction of the development and course of the disease more individualized, as well as to give our patients personalized recommendations about individual reproductive strategies.

Gonadotropin-releasing hormone agonist versus expectant management for treating multiple leiomyomas after myomectomy: the study protocol for a multicentre, prospective, randomised controlled clinical trial

INTRODUCTION

Leiomyoma recurrence is a major concern for long-term myomectomy management, especially for multiple leiomyomas. Gonadotropin-releasing hormone agonist (GnRHa) is one of the most effective medications to reduce the volume of fibroids and the uterus. However, its role in preventing recurrence after conservative surgery remains unclear. At present, there is no randomised clinical trial determining the efficacy of GnRHa treatment for preventing multiple leiomyomas recurrence after myomectomy.

METHODS AND ANALYSIS

We are conducting a phase IV randomised controlled trial in women aged 18-45 undergoing myomectomy for multiple leiomyomas. After surgery, women whose pathological result confirms multiple leiomyomas are randomised in a 1:1 ratio into an observation or GnRHa group. The primary outcome is the recurrence of either clinical symptoms or fibroids on imaging. Patients will be assessed for adverse events during the follow-up.

ETHICS AND DISSEMINATION

The study was approved by the Medical Ethics Committee of the Tongji Hospital Affiliated with the Tongji Medical College of Huazhong University of Science and Technology (TJ-IRB20180311) according to the submitted study protocol (V.1.0, 10 November 2017) and informed consent (V.1.0, 10 November 2017). The results will be presented at domestic and international conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR-IPR-17012992.

Growth of surgically confirmed leiomyomas in postmenopausal women: analysis of the influencing factors

OBJECTIVES

The aim of this study was to examine the growth of uterine leiomyomas in postmenopausal women and evaluate the influencing factors associated with fibroid growth.

METHODS

We retrospectively analyzed the medical records of postmenopausal women with fibroids between 2015 and 2020. All women received at least 2 transvaginal ultrasound examinations within a 6-month interval. All fibroids were verified via surgery. The postoperative pathology of all tumors was uterine fibroid. We calculated the fibroid volume using the ellipsoid volume formula and evaluated the growth rate of fibroids within 6 months simultaneously. Univariable analysis and a linear mixed-effects model were used to assess the factors influencing fibroid growth.

RESULTS

A total of 102 postmenopausal women with a total of 132 fibroids were assessed. The median growth rate of surgically confirmed fibroids in postmenopausal women was 12.9% every 6 months (from -61.4% to 184.1%). Obesity was associated with fibroid growth (P < 0.05). Notably, the estimated growth rates of fibroids in obese and overweight women were 26.6% (95% confidence interval [CI]: 2.3-50.9) and 15.9% (95% CI: 0.4-31.4) higher than those in women of normal weight, respectively. The growth of fibroids varied by the initial tumor size (P < 0.05). The estimated growth rate of larger fibroids (≥5.0 cm diameter) was reduced 30.0% (95% CI: -52.4 to -7.5) compared with that of small fibroids (<3.0 cm diameter).

CONCLUSIONS

Uterine fibroids continually grow in some postmenopausal women. Obesity and small fibroids (<3.0 cm diameter) may contribute to higher growth rates of fibroids.

Modelling fibroid pathology: development and manipulation of a myometrial smooth muscle cell macromolecular crowding model to alter extracellular matrix deposition

Current treatment options for uterine fibroids are limited to hormonal manipulation or surgical intervention. We aimed to develop an in vitro model to mirror collagen deposition and extracellular matrix (ECM) formation, the principal features of uterine fibroids, to enable testing of novel therapeutics. Macromolecular crowding with Ficoll 400 and Ficoll 70 in cultures of human uterine myometrial smooth muscle cells containing ascorbic acid, provided the basis for this model. These culture conditions mimic the 'crowded' nature of the in vivo extracellular environment by incorporating neutral, space-filling macromolecules into conventional cell cultures. This method of culture facilitates appropriate ECM deposition, thus closely representing the in vivo fibrotic phenotype of uterine fibroids. Macromolecular crowding in Ficoll cultures containing ascorbic acid reduced myometrial smooth muscle cell proliferation and promoted collagen production. Under these conditions, collagen was processed for extracellular deposition as demonstrated by C-propeptide cleavage from secreted procollagen. The fibrosis marker activin was increased relative to its natural inhibitor, follistatin, in crowded culture conditions while addition of exogenous follistatin reduced collagen (Col1A1) gene expression. This in vitro model represents a promising development for the testing of therapeutic interventions for uterine fibroids. However, it does not recapitulate the full in vivo pathology which can include specific genetic and epigenetic alterations that have not been identified in the myometrial smooth muscle (hTERT-HM) cell line. Following screening of potential therapeutics using the model, the most promising compounds will require further assessment in the context of individual subjects including those with genetic changes implicated in fibroid pathogenesis.

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.

Understanding the Impact of Uterine Fibroids on Human Endometrium Function

Uterine fibroids (leiomyomas) are the most common benign gynecological tumors in women of reproductive age worldwide. They cause heavy menstrual bleeding, usually leading to severe anemia, pelvic pain/pressure, infertility, and other debilitating morbidities. Fibroids are believed to be monoclonal tumors arising from the myometrium, and recent studies have demonstrated that fibroids actively influence the endometrium globally. Studies suggest a direct relationship between the number of fibroids removed and fertility problems. In this review, our objective was to provide a complete overview of the origin of uterine fibroids and the molecular pathways and processes implicated in their development and growth, which can directly affect the function of a healthy endometrium. One of the most common characteristics of fibroids is the excessive production of extracellular matrix (ECM) components, which contributes to the stiffness and expansion of fibroids. ECM may serve as a reservoir of profibrotic growth factors such as the transforming growth factor β (TGF-β) and a modulator of their availability and actions. Fibroids also elicit mechanotransduction changes that result in decreased uterine wall contractility and increased myometrium rigidity, which affect normal biological uterine functions such as menstrual bleeding, receptivity, and implantation. Changes in the microRNA (miRNA) expression in fibroids and myometrial cells appear to modulate the TGF-β pathways and the expression of regulators of ECM production. Taken together, these findings demonstrate an interaction among the ECM components, TGF-β family signaling, miRNAs, and the endometrial vascular system. Targeting these components will be fundamental to developing novel pharmacotherapies that not only treat uterine fibroids but also restore normal endometrial function.

Emerging Roles of Long Non-coding RNAs in Uterine Leiomyoma Pathogenesis: a Review

Uterine leiomyoma (UL), as the most prevalent type of women's health disorders, is a benign tumor that originates from the smooth muscle cell layer of the uterus. A great number of associated complications are observed including infertility, miscarriage, bleeding, pain, dysmenorrhea, menorrhagia, and dyspareunia. Although the etiology of UL is largely undefined, environmental and genetic factors are witnessed to engage in the UL development. As long non-coding RNAs (lncRNAs) are involved in various types of cellular functions, in recent years, a great deal of attention has been drawn to them and their possible roles in UL pathogenesis. Moreover, they have illustrated their potential to be promising candidates for UL treatment. In this review paper, firstly, an overview of UL pathogenesis is presented. Then, the regulation of lncRNAs in UL and their possible mechanisms in cancer development are reviewed. Eventually, therapeutic approaches targeting lncRNAs in various cancers and UL are explored.

Contrast-Enhanced Ultrasound for Monitoring Non-surgical Treatments of Uterine Fibroids: A Systematic Review

Non-surgical treatment options for uterine fibroids are uterine artery embolization (UAE), high-intensity focused ultrasound ablation (HIFUA), and percutaneous microwave ablation (PMWA). Magnetic resonance imaging (MRI) is the reference standard imaging method before and after these procedures. Contrast-enhanced ultrasound (CEUS) has been studied as an alternative to MRI for evaluating the fibroids' characteristics and responses to non-surgical treatments. PubMed, Ovid MEDLINE and Scopus databases were searched for literature published from January 2000 through June 7, 2020, that investigated the application of CEUS as an adjunct to monitor UAE, HIFUA or PMWA in human uterine fibroid treatments. Two independent reviewers analyzed 128 publications, out of which 17 were included. Based on this systematic review, CEUS provides detailed data about fibroid volume and vascularization prior, during and post UAE, and it helps determine the endpoint of the procedure. HIFUA with intra-procedural CEUS has faster volume shrinkage over a shorter time period with less needed energy and provides early detection of residual tissue after HIFUA. CEUS and contrast-enhanced MRI have sufficient agreement to be used interchangeably in the clinic to evaluate the therapeutic effect of PMWA and HIFUA on fibroids.

Cross-talk between Janus kinase-signal transducer and activator of transcription pathway and transforming growth factor beta pathways and increased collagen1A1 production in uterine leiomyoma cells

OBJECTIVE

To characterize the potential interaction between interleukin-6 (IL6), Janus kinase (JAK)-signal transducer and activator of transcription (STAT)-3 (JAK/STAT3) pathway, and Transforming growth factor beta (TGFβ)-3 , and to determine whether such cross-talk was a contributing factor in the dysregulation of type I collagen production in leiomyomas.

DESIGN

Laboratory study.

SETTING

University research laboratory.

PATIENTS

None.

INTERVENTIONS

Exposure of leiomyoma and myometrial cell lines to IL6 and STAT3 activators/inhibitors. Western immunoblot analysis and immunohistochemistry.

MAIN OUTCOME MEASURES

Expression of STAT3, pSTAT3, SOCS3, COL1A1, and TGFb3.

RESULTS

We observed that IL6 increased pSTAT3 as well as collagen1A1 in uterine leiomyoma cells. Direct activation of the JAK/STAT3 pathway increased collagen1A1 production in leiomyoma cells, whereas inhibition of the pathway significantly decreased collagen1A1 production. We further observed that modulation of the JAK/STAT3 pathway also increased the expression of TGFβ3 protein. Leiomyoma cells exposed to TGFβ3 demonstrated a significant decrease in pSTAT3 protein. Myometrial cells demonstrated a less sensitive response to STAT3 modulation and collagen production.

CONCLUSION

Cross-talk between the TGFβ pathway and JAK/STAT3 pathway contributes to the fibrotic nature of uterine leiomyomas.

YAP/TAZ are Activated by Mechanical and Hormonal Stimuli in Myometrium and Exhibit Increased Baseline Activation in Uterine Fibroids

Uterine fibroids (UFs) are benign myometrial neoplasms. The mechanical environment activates signaling through the Hippo pathway effectors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding domain (TAZ) in other fibrotic disorders. Here, we assess the differences in YAP/TAZ responsiveness to signals in UF compared with myometrium (Myo). Matched samples of UF and Myo were collected. Atomic force microscopy (AFM) was used to determine in situ stiffness. Cells were plated sparsely on hydrogels or at confluence. Ten nanomolars of estradiol (E2) and 100 nM progesterone (P4) were used. Immunostaining for YAP/TAZ and extracellular matrix (ECM) proteins was performed. Cells were incubated with control or YAP1 (YAP)/WWTR1 (TAZ) small interfering RNA (siRNA). Real time qPCR was completed for connective tissue growth factor (CTGF). Cells were treated with verteporfin (a YAP inhibitor) or Y27632 (a ROCK inhibitor), and ECM gene expression was analyzed. Paired t test and Wilcoxon sign-rank test were used. AFM-measured tissue stiffness and YAP/TAZ nuclear localization in situ and in confluent cells were higher in UF compared with Myo (p < 0.05). Decreasing substrate stiffness reduced YAP/TAZ nuclear localization for both Myo and UF (p = 0.05). Stimulating cells with E2 or P4 increased YAP/TAZ nuclear localization, but only in Myo (p = 0.01). UFs had increased FN, COLI, and COLIII deposition. Following siRNA targeting, CTGF was found to be statistically decreased. Verteporfin treatment reduced cell survival and reduced FN deposition. Treatment with Y27632 demonstrated better cell tolerance and a reduction in ECM deposition. The mechanosensitive pathway may be linked to YAP/TAZ function and involved in transducing fibroid growth.

Putative human myometrial and fibroid stem-like cells have mesenchymal stem cell and endometrial stromal cell properties

STUDY QUESTION

Can endometrial stromal stem/progenitor cell markers, SUSD2 and CD146/CD140b, enrich for human myometrial and fibroid stem/progenitor cells?

SUMMARY ANSWER

SUSD2 enriches for myometrial and fibroid cells that have mesenchymal stem cell (MSC) characteristics and can also be induced to decidualise.

WHAT IS KNOWN ALREADY

Mesenchymal stem-like cells have been separately characterised in the endometrial stroma and myometrium and may contribute to diseases in their respective tissues.

STUDY DESIGN, SIZE, DURATION

Normal myometrium, fibroids and endometrium were collected from hysterectomies with informed consent. Primary cells or tissues were used from at least three patient samples for each experiment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Flow cytometry, immunohistochemistry and immunofluorescence were used to characterise tissues. In vitro colony formation in normoxic and hypoxic conditions, MSC lineage differentiation (osteogenic and adipogenic) and decidualisation were used to assess stem cell activity. Xenotransplantation into immunocompromised mice was used to determine in vivo stem-like activity. Endpoint measures included quantitative PCR, colony formation, trichrome, Oil Red O and alkaline phosphatase activity staining.

MAIN RESULTS AND THE ROLE OF CHANCE

CD146+CD140b+ and/or SUSD2+ myometrial and fibroid cells were located in the perivascular region and formed more colonies in vitro compared to control cells and differentiated down adipogenic and osteogenic mesenchymal lineages in vitro. SUSD2+ myometrial cells had greater in vitro decidualisation potential, and SUSD2+ fibroid cells formed larger tumours in vivo compared to control cells.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Markers used in this study enrich for cells with stem/progenitor cell activity; however, they do not distinguish stem from progenitor cells. SUSD2+ myometrial cells express markers of decidualisation when treated in vitro, but in vivo assays are needed to fully demonstration their ability to decidualise.

WIDER IMPLICATIONS OF THE FINDINGS

These results suggest a possible common MSC for the endometrial stroma and myometrium, which could be the tumour-initiating cell for uterine fibroids.

STUDY FUNDING/COMPETING INTEREST(S)

These studies were supported by NIH grants to JMT (R01OD012206) and to ALP (F32HD081856). The authors certify that we have no conflicts of interest to disclose.

Natural Antioxidant Resveratrol Suppresses Uterine Fibroid Cell Growth and Extracellular Matrix Formation In Vitro and In Vivo

Resveratrol (RSV) is a polyphenolic phytoalexin found in peanuts, grapes, and other plants. Uterine fibroids (UF) are benign growths that are enriched in extracellular matrix (ECM) proteins. In this study, we aimed to investigate the effects of RSV on UF using in vivo and in vitro approaches. In mouse xenograft models, tumors were implanted through the subcutaneous injection of Eker rat-derived uterine leiomyoma cells transfected with luciferase (ELT-3-LUC) in five-week-old female nude (Foxn1^nu) mice. When the tumors reached a size of 50-100 mm³, the mice were randomly assigned to intraperitoneal treatment with RSV (10 mg·kg^-1) or vehicle control (dimethyl sulfoxide). Tumor tissues were assayed using an immunohistochemistry analysis. We also used primary human leiomyoma cells as in vitro models. Cell viability was determined using the sodium bicarbonate and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The protein expression was assayed using Western blot analysis. The messenger ribonucleic acid (mRNA) expression was assayed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell apoptosis was assayed using Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) and Hoechst 33342 staining. RSV significantly suppressed tumor growth in vivo and decreased the proportion of cells showing expression of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA). In addition, RSV decreased the protein expression of PCNA, fibronectin, and upregulated the ratio of Bax (Bcl-2-associated X) and Bcl-2 (B-cell lymphoma/leukemia 2) in vivo. Furthermore, RSV reduced leiomyoma cell viability, and decreased the mRNA levels of fibronectin and the protein expression of collagen type 1 (COL1A1) and α-SMA (ECM protein marker), as well as reducing the levels of β-catenin protein. RSV induced apoptosis and cell cycle arrest at sub-G1 phase. Our findings indicated the inhibitory effects of RSV on the ELT-3-LUC xenograft model and indicated that RSV reduced ECM-related protein expression in primary human leiomyoma cells, demonstrating its potential as an anti-fibrotic therapy for UF.

Uterine stem cells: from basic research to advanced cell therapies

BACKGROUND

Stem cell research in the endometrium and myometrium from animal models and humans has led to the identification of endometrial/myometrial stem cells and their niches. This basic knowledge is beginning to be translated to clinical use for incurable uterine pathologies. Additionally, the implication of bone marrow-derived stem cells (BMDSCs) in uterine physiology has opened the field for the exploration of an exogenous and autologous source of stem cells.

OBJECTIVE AND RATIONALE

In this review, we outline the progress of endometrial and myometrial stem/progenitor cells in both human and mouse models from their characterization to their clinical application, indicating roles in Asherman syndrome, atrophic endometrium and tissue engineering, among others.

SEARCH METHODS

A comprehensive search of PubMed and Google Scholar up to December 2017 was conducted to identify peer-reviewed literature related to the contribution of bone marrow, endometrial and myometrial stem cells to potential physiological regeneration as well as their implications in pathologies of the human uterus.

OUTCOMES

The discovery and main characteristics of stem cells in the murine and human endometrium and myometrium are presented together with the relevance of their niches and cross-regulation. The current state of advanced stem cell therapy using BMDSCs in the treatment of Asherman syndrome and atrophic endometrium is analyzed. In the myometrium, the understanding of genetic and epigenetic defects that result in the development of tumor-initiating cells in the myometrial stem niche and thus contribute to the growth of uterine leiomyoma is also presented. Finally, recent advances in tissue engineering based on the creation of novel three-dimensional scaffolds or decellularisation open up new perspectives for the field of uterine transplantation.

WIDER IMPLICATIONS

More than a decade after their discovery, the knowledge of uterine stem cells and their niches is crystalising into novel therapeutic approaches aiming to treat with cells those conditions that cannot be cured with drugs, particularly the currently incurable uterine pathologies. Additional work and improvements are needed, but the basis has been formed for this therapeutic application of uterine cells.

Reasons for different therapeutic effects of high-intensity focused ultrasound ablation on excised uterine fibroids with different signal intensities on T2-weighted MRI: a study of histopathological characteristics

OBJECTIVE

The objective of this study was to explore the correlations between the therapeutic effect of high intensity focused ultrasound (HIFU) and histopathological characteristics of excised uterine fibroids with different signal intensities as visualized on T2-weighted magnetic resonance imaging (MRI).

METHODS

We collected 47 specimens of uterine fibroids after surgical resection and classified them into four groups according to preoperative T2-weighted MRI hypo-intense, isointense, heterogeneous intense and homogeneous hyper-intense. Then, specimens in each group were irradiated by HIFU with the same parameters and the necrotic tissue volume was calculated. The smooth muscle cell (SMC) count and collagen fiber content were quantitatively measured and compared between different groups. We analyzed the correlation between the necrotic tissue volume and SMC count and the collagen fiber content.

RESULTS

Necrotic tissue volume gradually decreased from the hypo-intense group to the homogeneous hyper-intense group (p = .008). The SMC count from the hypo-intense group to the homogeneous hyper-intense group was 215.6 ± 59.3, 237.0(89.5), 232.3 ± 72.5 and 330.5 ± 30.9, respectively; collagen fiber content was 0.65 ± 0.07, 0.64 ± 0.10, 0.53 ± 0.11 and 0.41 ± 0.06, respectively. Comparison among the four groups showed that SMC count progressively increased (p = .001) but collagen fiber content progressively decreased (p = .000) from the hypo-intense group to the homogeneous hyper-intense group. Correlation analysis showed that necrotic tissue volume was negatively correlated with SMC count (R = -0.488, p=.013) but positively correlated with collagen fiber content (R = 0.534, p = .005).

CONCLUSIONS

Differences in histopathological characteristics may be one of the reasons for different therapeutic effects of HIFU ablation on uterine fibroids with different signal intensities on T2-weighted MRI.

Ulipristal Acetate Mediates Decreased Proteoglycan Expression Through Regulation of Nuclear Factor of Activated T-Cells (NFAT5)

Nuclear factor of activated T-cells (NFAT5) is a tissue specific, osmoadaptive transcription factor essential for the control of hydration homeostasis in mammalian cells. Nuclear factor of activated T-cells regulates osmolyte transporters aldo-keto reductase family 1 member B1 (AKR1B1) and solute carrier family 5 member 3 (SLC5A3) to maintain fluid equilibrium in cells. The osmotic potential of the extracellular matrix of leiomyomas is attributed to the role of proteoglycans. In leiomyoma cells, NFAT5 is overexpressed compared to myometrial cells. The selective progesterone receptor modulator, ulipristal acetate, has been reported to decrease the size of leiomyomas in clinical trials. When treated with ulipristal acetate, both patient leiomyoma tissue and leiomyoma cells grown in 3-dimensional cultures show a decrease in the expression of NFAT5 protein, solute transporters AKR1B1 and SLC5A3, and results in an associated decline in the expression of proteoglycans, versican, aggrecan, and brevican. In summary, ulipristal acetate induces changes in leiomyoma cell osmoregulation which result in a decrease in proteoglycan expression.

The ontogeny of myometrial stem cells in OCT4-GFP transgenic mouse model

BACKGROUND

Myometrium, the muscular wall of the uterus, is an active organ markedly remodeled during a woman's reproductive life, especially during pregnancy. Different studies using the 5-bromo-2'-deoxyuridine and side population methods in murine and human myometrium have suggested the presence of somatic stem cells in this tissue because of its remarkable regenerative capacity. Recently, our group has developed a surface-marker (Stro1/CD44)-specific approach to isolate and characterize myometrial somatic stem cells (SSCs) from humans and rats.

OBJECTIVE

In this study, we aimed to identify and localize the putative myometrial stem cell population in the murine uterus by using the specific surface markers, Nanog/CD44.

METHODS

Uteri from OCT4-GFP transgenic mice at different early-life time points were analyzed via single and double immunohistochemistry to co-localize myometrial stem cell marker CD44 with other general stemmness markers, e.g., Nanog and Oct-4. Finally, we correlated the frequency of myometrial stem cells in vivo with the expression of sex steroid hormone receptors, estrogen receptor α (ERα), and progesterone receptors A and B (PR A&B).

RESULTS

Nanog⁺/CD44⁺ stem cells were present in murine myometrium. Both stem cell markers were shown to co-localize with Oct-4 expression. Time-course experiments demonstrated that their percentages were significantly lower at the pre-sexual age of 1 week than at the sexually mature ages of 3 to 24 weeks. Importantly, both ERα and PR A&B were abundantly expressed in the myometrium at ages 1, 3 and 4 weeks.

CONCLUSIONS

We demonstrated that murine CD44⁺ myometrial cells have features of somatic stem cells with the expression of typical undifferentiated markers. Furthermore, our results suggest that myometrial stem cells are sex steroid hormone dependent, likely via paracrine pathway, and increase in numbers with reproductive maturity and rise in serum estrogen and progesterone levels around 3 weeks of age in mice. The abundance and early onset expression of ER/PR emphasize the vulnerability of neonatal myometrium to environmental endocrine disruptors which can potentially lead to permanent reprograming and adult onset of myometrial disorders such as uterine fibroids.

Moving Toward Individualized Medicine for Uterine Leiomyomas

Uterine leiomyomas are common and life-altering for many women. Despite a wide range of symptoms, varying characteristics of the uterus and the leiomyomas themselves, and many alternatives, hysterectomy accounts for almost three fourths of all surgical therapy, yet there is increasing evidence for a variety of procedural therapies for symptomatic leiomyomas and a new generation of medical therapies under development. With increasing evidence of long-term risk from hysterectomy and new data regarding leiomyoma biology, individualized medical approaches to leiomyomas are likely in the near future. Key biological attributes that influence this disease process are common driver mutations and the new appreciation of the interaction of smooth muscle cells and fibroblasts. Additionally, the interaction between cell types and steroid hormone responsiveness likely plays a role in pathogenesis that can be leveraged in individualized therapy. However, given the independent clonal nature of leiomyomas within the same uterus, moving in the direction of biopsies for individual leiomyomas to understand the biology is unlikely to be fruitful. Use of advanced imaging will likely continue to evolve not only to accurately predict malignant disease, including sarcomas, but to predict leiomyoma subtypes, response to therapy, or both. We predict the continued evolution of therapy from excisional or interventional therapies to medical therapies and ultimately prediction of at-risk individuals. Ideally, individualized therapies will offer primary prevention for women at high risk of leiomyomas and secondary prevention after initial treatment.

Vitamin D and Uterine Fibroids-Review of the Literature and Novel Concepts

This article provides a detailed review of current knowledge on the role of vitamin D and its receptor in the biology and management of uterine fibroids (UFs). Authors present ideas for future steps in this area. A literature search was conducted in PubMed using the following key words: "uterine fibroid" and "vitamin D". The results of the available studies, published in English from January 2002 up to April 2018, have been discussed. Vitamin D is a group of steroid compounds with a powerful impact on many parts of the human body. This vitamin is believed to regulate cell proliferation and differentiation, inhibit angiogenesis, and stimulate apoptosis. Nowadays, hypovitaminosis D is believed to be a major risk factor in the development of UFs. In many studies vitamin D appears to be a powerful factor against UFs, resulting in inhibition of tumor cell division and a significant reduction in its size, however, the exact role of this compound and its receptor in the pathophysiology of UFs is not fully understood. According to available studies, vitamin D and its analogs seem to be promising, effective, and low-cost compounds in the management of UFs and their clinical symptoms, and the anti-tumor activities of vitamin D play an important role in UF biology. The synergy between vitamin D and selected anti-UF drugs is a very interesting issue which requires further research. Further studies about the biological effect of vitamin D on UF biology are essential. Vitamin D preparations (alone or as a co-drugs) could become new tools in the fight with UFs, with the additional beneficial pleiotropic effect.

HMGA2 and MED12 alterations frequently co-occur in uterine leiomyomas

OBJECTIVE

Around 70% of uterine leiomyomas show MED12 mutations while overexpression of HMGA2 mRNA is also highly frequent in fibroids. However, previous studies suggested that alterations in both genes are mutually exclusive. In the present study, we searched for mutation in MED12 and analyzed the expression of HMGA2 in 20 uterine leiomyomas and their matched myometrium.

METHODS

Normal and tumor tissue obtained from premenopausal women who underwent hysterectomy were collected after surgery and DNA, RNA and proteins were isolated and analyzed for MED12 mutations using Sanger sequencing, HMGA2 mRNA expression by quantitative PCR and HMGA2 protein detection by western blot and immunohistochemistry.

RESULTS

75% of the tumors displayed MED12 mutation while 65% of them showed overexpression of HMGA2 mRNA in leiomyomata compared to myometrial tissues (p = 0,0008). Interestingly, 50% of the tumors showed mutations in MED12 and overexpression of HMGA2 mRNA simultaneously, suggesting that alterations in both genes are relatively frequent in uterine leiomyomas.

CONCLUSIONS

Contrary to the present findings, former studies showed that mutations in MED12 and overexpression of HMGA2 are mutually exclusive. Here, we observed that overexpression of HMGA2 mRNA in tumors measured by quantitative PCR and compared to myometrium is a common phenomenon in fibroids and is frequently associated with MED12 mutations. In addition, the common clonal origin of tumors overexpressing HMGA2 mRNA and its expression in few myometrial tissue points to HMGA2 up-regulation as an early event in leiomyoma tumorigenesis.

The Comparing Options for Management: PAtient-centered REsults for Uterine Fibroids (COMPARE-UF) registry: rationale and design

BACKGROUND

Uterine fibroids are common in premenopausal women, yet comparative effectiveness research on uterine fibroid treatments is rare.

OBJECTIVE

The purpose of this study was to design and establish a uterine fibroid registry based in the United States to provide comparative effectiveness data regarding uterine fibroid treatment.

STUDY DESIGN

We report here the design and initial recruitment for the Comparing Options for Management: Patient-centered REsults for Uterine Fibroids (COMPARE-UF) registry (Clinicaltrials.gov, NCT02260752), funded by the Agency for Healthcare Research and Quality in collaboration with the Patient-Centered Outcomes Research Institute. COMPARE-UF was designed to help answer critical questions about treatment options for women with symptomatic uterine fibroids. Women who undergo a procedure for uterine fibroids (hysterectomy, myomectomy [abdominal, hysteroscopic, vaginal, and laparoscopic/robotic], endometrial ablation, radiofrequency fibroid ablation, uterine artery embolization, magnetic resonance-guided focused ultrasound, or progestin-releasing intrauterine device insertion) at 1 of the COMPARE-UF sites are invited to participate in a prospective registry with 3 years follow up for postprocedural outcomes. Enrolled participants provide annual follow-up evaluation through an online portal or through traditional phone contact. A central data abstraction center provides information obtained from imaging, operative or procedural notes, and pathology reports. Women with uterine fibroids and other stakeholders are a key part of the COMPARE-UF registry and participate at all points from study design to dissemination of results.

RESULTS

We built a network of 9 clinical sites across the United States with expertise in the care of women with uterine fibroids to capture geographic, racial, ethnic, and procedural diversity. Of the initial 2031 women who were enrolled in COMPARE-UF, 42% are self-identified as black or African American, and 40% are ≤40 years old, with 16% of participants <35 years old. Women who undergo myomectomy comprise the largest treatment group at 46% of all procedures, with laparoscopic or robotic myomectomy comprising the largest subset of myomectomies at 19% of all procedures. Hysterectomy is the second most common treatment within the registry at 38%.

CONCLUSION

In response to priorities that were identified by our patient stakeholders, the initial aims within COMPARE-UF will address how different procedures that are used to treat uterine fibroids compare in terms of long-lasting symptom relief, potential for recurrence, medical complications, improvement in quality of life and sexual function, age at menopause, and fertility and pregnancy outcomes. COMPARE-UF will generate evidence on the comparative effectiveness of different procedural options for uterine fibroids and help patients and their caregivers make informed decisions that best meet an individual patient's short- and long-term preferences. Building on this infrastructure, the COMPARE-UF team of investigators and stakeholders, including patients, collaborate to identify future priorities for expanding the registry, such as assessing the efficacy of medical therapies for uterine fibroids. COMPARE-UF results will be disseminated directly to patients, providers, and other stakeholders by traditional academic pathways and by innovative methods that include a variety of social media platforms. Given demographic differences among women who undergo different uterine fibroid treatments, the assessment of comparative effectiveness for this disease through clinical trials will remain difficult. Therefore, this registry provides optimized evidence to help patients and their providers better understand the pros and cons of different treatment options so that they can make more informed decisions.

Proteomic Characterization of the Extracellular Matrix of Human Uterine Fibroids

Uterine leiomyomas (fibroids) are the most common benign tumors that are associated with increased production of extracellular matrix (ECM). Excessive ECM deposition plays a major role in the enlargement and stiffness of these tumors and contributes to clinical symptoms, such as abnormal bleeding and abdominal pain. However, no study so far has explored the global composition of the ECM of fibroids and normal myometrium. In this study, we performed a systematic ECM enrichment procedure and comparative proteomic analyses to profile the ECM composition of genetically annotated different-sized fibroids (small, medium, and large) and adjacent normal myometrium (ANM). Our matrisome analysis identified a combined total of 108, 126, 126, and 130 unique ECM and ECM-associated proteins with a confidence corresponding to a false discovery rate <1% in ANM and in small, medium, and large fibroids, respectively. The majority of fibroid ECM proteins belong to the core matrisome that includes glycoproteins, collagens, and proteoglycans. Considering that the small-sized fibroids represent the initial stages of leiomyogenesis, we highlighted some of the most abundant and important upregulated ECM proteins in small fibroids (i.e., POSTN, TNC, COL3A1, COL24A1, and ASPN). Furthermore, we revealed 30 unique ECM proteins that exist only in fibroids but that are not present in ANM regardless of MED12 mutation. We propose that some of the proteins identified represent potential novel ECM drug targets that may change the paradigm of fibroid treatment.

Multiclonal tumor origin: Evidence and implications

An accurate understanding of the clonal origins of tumors is critical for designing effective strategies to treat or prevent cancer and for guiding the field of cancer risk assessment. The intent of this review is to summarize evidence of multiclonal tumor origin and, thereby, contest the commonly held assumption of monoclonal tumor origin. This review describes relevant studies of X chromosome inactivation, analyses of tumor heterogeneity using other markers, single cell sequencing, and lineage tracing studies in aggregation chimeras and engineered rodent models. Methods for investigating tumor clonality have an inherent bias against detecting multiclonality. Despite this, multiclonality has been observed within all tumor stages and within 53 different types of tumors. For myeloid tumors, monoclonal tumor origin may be the predominant path to cancer and a monoclonal tumor origin cannot be ruled out for a fraction of other cancer types. Nevertheless, a large body of evidence supports the conclusion that most cancers are multiclonal in origin. Cooperation between different cell types and between clones of cells carrying different genetic and/or epigenetic lesions is discussed, along with how polyclonal tumor origin can be integrated with current perspectives on the genesis of tumors. In order to develop biologically sound and useful approaches to cancer risk assessment and precision medicine, mathematical models of carcinogenesis are needed, which incorporate multiclonal tumor origin and the contributions of spontaneous mutations in conjunction with the selective advantages conferred by particular mutations and combinations of mutations. Adherence to the idea that a growth must develop from a single progenitor cell to be considered neoplastic has outlived its usefulness. Moving forward, explicit examination of tumor clonality, using advanced tools, like lineage tracing models, will provide a strong foundation for future advances in clinical oncology and better training for the next generation of oncologists and pathologists.

Factors affecting the loss of MED12-mutated leiomyoma cells during in vitro growth

Uterine leiomyomas (UL) are the most prevalent symptomatic human tumors at all and somatic mutations of the gene encoding mediator subcomplex 12 (MED12) constitute the most frequent driver mutations in UL. Recently, a rapid loss of mutated cells during in vitro growth of UL-derived cell cultures was reported, resulting in doubts about the benefits of UL-derived cell cultures. To evaluate if the rapid loss of MED12-mutated cells in UL cell cultures depends on in vitro passaging, we set up cell cultures from nine UL from 40–50 year old Caucasian patients with at least one UL. Cultured UL cells were investigated for loss of MED12-mutated cells. Genetic characterization of native tumor samples and adjacent myometrium was done by array analysis. “Aged” primary cultures without passaging were compared to cells of three subsequent passages. Comparative analyses of the mutated/non-mutated ratios between native tissue, primary cells, and cultured tumor cells revealed a clear decrease of MED12-mutated cells. None of the tumors showed gross alterations of the array profiles, excluding the presence of gross genomic imbalances besides the MED12 mutations as a reason for the intertumoral variation in the loss of MED12-mutated cells. Albeit at a lesser rate, loss of MED12-mutated cells from cell cultures of UL occurs even without passaging thus indicating the requirement of soluble factors or matrix components lacking in vitro. Identification of these factors can help to understand the mechanisms of the growth of the most frequent type of uterine leiomyomas and to decipher novel drug targets.

Current medical treatment of uterine fibroids

Uterine fibroids (leiomyomas or myomas), benign monoclonal tumors, are the most common benign tumors in women. Heavy or prolonged menstrual bleeding, abnormal uterine bleeding, resultant anemia, pelvic pain, infertility, and/or recurrent pregnancy loss are generally associated with uterine fibroids. Although curative treatment of this tumor relies on surgical therapies, medical treatments are considered the first-line treatment to preserve fertility and avoid or delay surgery. The aim of this review is to provide available and emerging medical treatment options for symptomatic uterine fibroids. Literature review and consensus of expert opinion. Many uterine fibroids are asymptomatic and require no intervention, although it is advisable to follow-up patients to document stability in size and growth. Fibroid-associated symptoms include heavy menstrual bleeding and pain or pelvic discomfort. The association between infertility and fibroids increases with age. Treatment options for symptomatic uterine fibroids - include medical, surgical, and radiologically guided interventions. Various medical therapies are now available for women with uterine fibroids, although each therapy has its own advantages and disadvantages. Currently, gonadotrophin-releasing hormone (GnRH) agonists and selective progesterone receptor modulators (SPRMs) are the most effective medical therapies, with the most evidence to support their reduction of fibroid volume and symptomatic improvement in menstrual bleeding. The choice of treatment depends on the patient's personal treatment goals, as well as efficacy and need for repeated interventions.

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.

Uterine fibroids - what's new?

Uterine fibroids are the commonest benign tumours of women and affect all races with a cumulative lifetime risk of around 70%. Despite their high prevalence and the heavy economic burden of treatment, fibroids have received remarkably little attention compared to common female malignant tumours. This article reviews recent progress in understanding the biological nature of fibroids, their life cycle and their molecular genetic origins. Recent progress in surgical and interventional management is briefly reviewed, and medical management options, including treatment with selective progesterone receptor modulators, are also discussed.