Gene expression analysis reveals an angiogenic profile in uterine leiomyoma pseudocapsule

Uterine Fibroids (Leiomyomata) and Heavy Menstrual Bleeding

Uterine Fibroids, or leiomyomata, affect millions of women world-wide, with a high incidence of 75% within women of reproductive age. In ~30% of patients, uterine fibroids cause menorrhagia, or heavy menstrual bleeding, and more than half of the patients experience symptoms such as heavy menstrual bleeding, pelvic pain, or infertility. Treatment is symptomatic with limited options including hysterectomy as the most radical solution. The genetic foundations of uterine fibroid growth have been traced to somatic driver mutations (MED12, HMGA2, FH -/-, and COL4A5-A6). These also lead to downstream expression of angiogenic factors including IGF-1 and IGF-2, as opposed to the VEGF-driven mechanism found in the angiogenesis of hypoxic tumors. The resulting vasculature supplying the fibroid with nutrients and oxygen is highly irregular. Of particular interest is the formation of a pseudocapsule around intramural fibroids, a unique structure within tumor angiogenesis. These aberrations in vascular architecture and network could explain the heavy menstrual bleeding observed. However, other theories have been proposed such as venous trunks, or venous lakes caused by the blocking of normal blood flow by uterine fibroids, or the increased local action of vasoactive growth factors. Here, we review and discuss the evidence for the various hypotheses proposed.

Intracervical intracapsular myomectomy using loop ligation: a proposed technique

Performing laparoscopic myomectomy for an intracervical myoma, especially a single giant myoma, is challenging. Only skilled surgeons attempt this operation. Surgeons frequently encounter cases of massive intraoperative bleeding, difficulty suturing the cervical incision, risk of injuring the neighbouring tissues, haematoma formation and conversion to laparotomy or hysterectomy. We previously developed a the technique of loop ligation of the pseudocapsule and have been using it to treat sizeable intracervical myomas laparoscopically. Its advantages include less blood loss, lower risk of injuries to the neighbouring tissues, maintenance of the cervical canal and sparing of the pseudocapsule. This technique is safe and feasible, and facilitates fertility.

Submucous Fibroids, Fertility, and Possible Correlation to Pseudocapsule Thickness in Reproductive Surgery

Background and Objectives

Fibroids are related to infertility. Fibroid pseudocapsule is a neurovascular bundle surrounding leiomyomas rich of neurofibers involved in myometrial biology. Authors evaluated, by a case-control study, the fibroid pseudocapsule (FP) thickness by ultrasound (US) and the histological measurements, according to uterine location of fibroids.

Methods

137 consecutive patients undergoing hysterectomy for uterine myomas were enrolled and 200 myomas were evaluated. Before surgery, patients underwent an ultrasound (US) investigation to evaluate the number, the size, and the location of fibroids. After surgery, myoma-pseudocapsule-myometrium specimens were measured and evaluated by a single expert pathologist. Both US and histological data were collected and statistically analyzed.

Results

Our results confirm the relevant difference of FP thickness, particularly represented under the endometrium for submucous LMs. FPs near the endometrial cavity were considerably thicker than those of both intramural fibroids and subserous fibroids measured by US (P=0.0001) and histology (P=0.0001). A clear cut-off measurement at 2 mm (P=0.0001) was found between endometrial FPs and all other FPs for either US or histology measurements.

Conclusion

The thickness of FP is considerably higher near the endometrial cavity when compared to those of both intramural and subserous LMs, suggesting a potential role either in fertility or in myometrial healing.

Biological functions and role of CCN1/Cyr61 in embryogenesis and tumorigenesis in the female reproductive system (Review)

Cysteine-rich angiogenic inducer 61 (CCN1/Cyr61) is a prompt response transcription product activated by growth factors. As a member of the CCN family, it mediates cell survival, proliferation, differentiation, migration, adhesion and synthesis of the extracellular matrix by binding directly to the integrins and heparin sulfate proteoglycans or activating multiple signaling transduction pathways. It has previously been demonstrated that CCN1/Cyr61 exhibits an important role in the female reproductive system during embryogenesis and tumorigenesis. However, the functions of CCN1/Cyr61 in the female reproductive system have not been systematically investigated, therefore, the primary aim of the present review is to introduce the role and function of CCN1/Cyr61 in the female reproductive system. The current review presents the molecular structure and biological function of CCN1/Cyr61 and provides detailed data on its expression pattern and contribution to the female reproductive system, including the role in embryogenesis and tumorigenesis.

Comment on "Oestrogen-induced angiogenesis and implantation contribute to the development of parasitic myomas after laparoscopic morcellation"

BACKGROUND

The cause of contamination and dissemination of leiomyoma tissue particles and cells in the peritoneal cavity during myomectomy is a challenging issue for both clinicians and researchers. Therefore, the article by Huang et al. recently published in your journal is the subject of this letter.

MAIN BODY

We comment on the role of laparoscopic condition in xenograft implantation and also highlighted the shortcomings of this study. The surgical technique of intramural fibroid enucleation, cell spillage during morcellation and postsurgical hormonal impact on the development of parasitic myomas become evident, while the contribution of CO2 insufflation, the fibroid's nature, mutations and pseudocapsule impacts on angiogenesis are not clear. In addition, an exploration of the exact origin of implanted fragments harvested from the fibroid tissue and their nature might play a significant role in the implantation and the angiogenesis induction ability of xenografts.

CONCLUSION

Taking into account the current literature in the scope of this study, we suggest that the factors involved in development of parasitic myomas can be classified as confirmed and doubtful contributions.

Fibroid vascularisation assessed with three-dimensional power Doppler ultrasound is a predictor for uterine fibroid growth: a prospective cohort study

OBJECTIVE

To analyse fibroid vascularisation measured with three-dimensional (3D) power Doppler in relation to absolute fibroid volume change during 12 months of follow up and in relation to fibroid growth rate per year.

DESIGN

A prospective cohort study was performed between March 2012 and March 2014.

SETTING

Outpatient clinic of the VU medical centre, Amsterdam.

POPULATION OR SAMPLE

All premenopausal women diagnosed with a maximum of two fibroids with expectant management were consecutively included.

METHODS

Three-dimensional ultrasound including power Doppler was performed at baseline, 3, 6 and 12 months. Volume and vascular parameters were calculated using VOCAL software.

MAIN OUTCOME MEASURES

The relationship between vascular index (VI) at baseline and fibroid volume over time was analysed using linear mixed model analyses for repeated measurements. Second, the relationship between VI at baseline and fibroid growth rate per year was calculated using linear regression analyses. Analyses were adjusted for possible confounders.

RESULTS

In all, 66 women (mean age 42 years) completed 12 months of follow up without treatment. Baseline fibroid vascularisation (VI) measured with 3D power Doppler is correlated with fibroid volume at 12 months (P = 0.02 ). An increase of 1% in VI at baseline was associated with a 7.00-cm³ larger fibroid volume at 12 months. Furthermore, vascularisation was also associated with fibroid growth rate per year (P = 0.04).

CONCLUSION

In women with uterine fibroids without therapy, baseline vascularisation (VI) measured with 3D power Doppler is correlated with absolute fibroid volume change at 12 months and with fibroid growth rate per year.

TWEETABLE ABSTRACT

Fibroid vascularisation correlates with absolute fibroid volume change and fibroid growth rate per year.

Laparoscopic Myomectomy Using "Cold" Surgical Instruments for Uterine Corpus Leiomyoma: A Preliminary Report

To assess the feasibility and safety of laparoscopic myomectomy without coagulation for uterine corpus leiomyoma between 4 and 9 cm in diameter with types 2-5. A total of 109 patients with uterine corpus myoma, single or multiple, between 4 and 9 cm in diameter with types from 2 to 5 were included who underwent laparoscopic myomectomy without using any unipolar or bipolar coagulation. Surgery time, intraoperative blood loss, hemoglobin decline on the first day after surgery and average days of post-operative hospitalization were recorded. The mean operative time was 70 ± 25 min (range 35-140 min). Mean blood loss during operation was 138 ml (range 20-400 ml), mean hemoglobin decline on the first day after surgery was 1.5 ± 0.75 g/dl (range 0-3.2 g/dl), and mean hospitalization time was 3.2 days (range 2-6 days). No patient required a blood transfusion. There were no major post-operative complications. Laparoscopic myomectomy without coagulation is feasible and safe for uterine corpus leiomyoma between 4 and 9 cm in diameter with types 2-5.

Potential causes of subfertility in patients with intramural fibroids

BACKGROUND

Intramural leiomyomas have been long debated as a potential cause of infertility and pregnancy loss.

FINDINGS

Previous research has linked intramural fibroids to defective implantation, as well as to abnormal peristaltic events of the uterine smooth muscle. Previous reports describe the effects of intramural fibroids on normal human fertility and early pregnancy loss, specifically in regards to implantation failure.

CONCLUSION

A thorough understanding of prior research may direct new research focus, leading to better understanding of leiomyoma-associated infertility.

Uterine leiomyoma research

Uterine leiomyoma is the most common type of benign tumor in women of reproductive age. This disease is rare before menarche, and its incidence decreases after menopause. Uterine leiomyoma is known to be related to hormonal changes, but the precise underlying mechanism has yet to be determined. Although it is a benign disease, the most common form of management involves surgical intervention. Uterine leiomyoma is also related to infertility and obstetric complications. Here, we present a review of the literature regarding uterine leiomyoma and discuss management of this disease.

The use of 3D power Doppler ultrasound in the quantification of blood vessels in uterine fibroids: feasibility and reproducibility

BACKGROUND

To evaluate the interobserver agreement and discriminating value of three-dimensional power Doppler ultrasound (3D PDUS) in patients with fibroids.

METHODS

An observational prospective cohort study in 19 patients with fibroids. 3D PDUS was performed by one examiner and evaluated by three independent examiners in order to evaluate various vascular parameters: vascular index (VI), flow index, and vascular flow index of the fibroid, the vascular capsule and of its highest vascular area, using both manual and automatic contour modes. The intraclass correlation coefficient and discriminating values were calculated. The correlation between VI and volume was studied using Kendall's Tau test.

RESULTS

In the manual contour mode, the VIs of the fibroid and of the vascular capsule had the highest interobserver agreements (intraclass correlation coefficients of 0.89 and 0.87, respectively). Both parameters seem to have good discriminating values, given the large range of these parameters between different fibroids, independent of their volume. The vascularity of the fibroid and capsule was related. VI was not related to the volume of the fibroid.

CONCLUSIONS

VI assessed using 3D PDUS is a reproducible parameter in the assessment of fibroid vascularization with discriminating abilities. Additional studies are needed to further evaluate its validity and clinical relevance.

Missense mutations in exon 2 of the MED12 gene are involved in IGF-2 overexpression in uterine leiomyoma

Uterine leiomyoma (UL), the most common benign tumour found in females, is associated with many recurrent genetic aberrations, such as translocations, interstitial deletions and specific germline mutations. Among these, mutations affecting exon 2 of the mediator complex subunit 12 (MED12) gene are commonly detected in the majority of ULs. Mutational analysis of the MED12 gene, performed on 36 UL samples, revealed that 12 leiomyomas (33.4%) exhibited heterozygous missense mutations in codon 44 of exon 2 of the MED12 gene, four leiomyomas (11.1%) showed internal in-frame deletions, and two leiomyomas (5.5%) exhibited deletions involving intron 1-exon 2 junction, which caused a predicted loss of the splice acceptor. No mutations were detected in uterine myometrium (UM) and pseudocapsule (PC) samples, including those from women with a MED12 mutation in UL. These data showed that the PC is a healthy tissue that surrounds the UL to maintain UM integrity. Analysis of insulin-like growth factor 2 (IGF-2) and collagen type IV alpha 2 (COL4A2) mRNA expression levels in the same set of ULs revealed that only those with MED12 missense mutations expressed significantly higher levels of IGF-2 mRNA. In contrast, MED12 gene status does not appear to affect mRNA expression levels of the COL4A2 gene. On the basis of this finding, we suggest that the MED12 status stratifies the ULs into two mutually exclusive pathways of leiomyoma genesis, one with IGF-2 overexpression and the other with no IGF-2 activation. The occurrence of IGF-2 overexpression could be therapeutically targeted for the non-surgical treatment of leiomyomas.

Matrix production and remodeling as therapeutic targets for uterine leiomyoma

Uterine leiomyoma, commonly known as fibroids, is a benign neoplasm of smooth muscle in women. The incidence of clinically symptomatic fibroids in reproductive-age women is approximately 20 %, with nearly 80 % of black women suffering from this condition. Symptoms include severe pain and hemorrhage; fibroids are also a major cause of infertility or sub-fertility in women. Uterine leiomyoma consist of hyperplastic smooth muscle cells and an excess deposition of extracellular matrix, specifically collagen, fibronectin, and sulfated proteoglycans. Extracellular matrix components interact and signal through integrin-β1 on the surface of uterine leiomyoma smooth muscle cells, provide growth factor storage, and act as co-receptors for growth factor-receptor binding. ECM and growth factor signaling through integrin-β1 and growth factor receptors significantly increases cell proliferation and ECM deposition in uterine leiomyoma. Growth factors TGF-β, IGF, PDGF, FGF and EGF are all shown to promote uterine leiomyoma progression and signal through multiple pathways to increase the expression of genes encoding matrix or matrix-modifying proteins. Decreasing integrin expression, reducing growth factor action and inhibiting ECM action on uterine leiomyoma smooth muscle cells are important opportunities to treat uterine leiomyoma without use of the current surgical procedures. Both natural compounds and chemicals are shown to decrease fibrosis and uterine leiomyoma progression, but further analysis is needed to make inroads in treating this common women's health issue.

A combined ultrasound and histologic approach for analysis of uterine fibroid pseudocapsule thickness

Authors investigated 75 patients with uterine myomas, appraising whether fibroid pseudocapsule (FP) thickness varies depending on fibroid location, by a prospective cohort trial (level of evidence II-2) settled in University-affiliated Hospitals. Uteri were scanned via bidimensional and power Doppler ultrasound (US) to map the fibroids and record the FP thickness, prior to hysterectomy for symptomatic uterine fibroids. After hysterectomy, FP specimens were sampled and analyzed by pathologists. Ultrasound and histology data were matched. Pseudocapsule thickness of 108 fibroids was measured: subserosal fibroids (SSFs), intramural fibroids (IMFs), and fibroids near the endometrial cavity (FEC). The FEC's pseudocapsules were considerably thicker than those of IMF and SSF measured by US and histology (P = .001). A clear cutoff existed between FEC pseudocapsule thickness and all other pseudocapsules, with significant differences observed at 2 mm (P = .001). Similarity between histological and US measurements was observed only with IMF pseudocapsules, whereas FEC or SSF showed significant differences. The pseudocapsule of fibroids is considerably thicker near the endometrial cavity when compared to those of both IMFs and SSFs. Since fibroids closest to the endometrial cavity are the most involved in fertility and infertility and FP is considerably thicker near the endometrial cavity, it is possible to hypothesize an involvement of FP of fibroid near the endometrium since FP contains many neuropeptides and neurotransmitters that are physiologically active, even if these data may take on a broader meaning in a study on a larger number of patients.

Is adenomyosis a problem in reproduction and fertility?

Adenomyosis is defined as the presence of glandular foci beside the endometrium of uterus: in the myometrium and/or perimetrium depending on the progress of the disorder. So far, adenomyosis has been diagnosed in women and rodents, and studies conducted on cows have been rare. In this review we: (1) summarize the knowledge regarding adenomyosis, (2) compare the symptoms and aetiopathology between women and cows, (3) describe angiogenic uterine processes related to adenomyosis development and (4) outline the influence of adenomyosis on proper fertility processes in cattle (conception and fertility rates).