Lax Uterosacral Ligament and Urge Urinary Incontinence: MRI Findings in Symptomatic Patients Versus Healthy Volunteers

INTRODUCTION AND HYPOTHESIS

The objective was to explore the association between urge urinary incontinence (UUI) and lax uterosacral ligaments (USL) using MRI.

METHODS

Sixty-seven female participants were recruited prospectively: 41 continent volunteers (control group) and 26 patients with UUI. Static proton density- and T2-weighted turbo spin echo sequences of MR images were used. A radiologist employed a standardized grid system to record structural observations of the USLs on sequentially numbered axial MR images and then applied a four-point grading scale to assess ligament visibility. MR images were interpreted by a radiologist and a urologist, and then validated by an expert radiologist.

RESULTS

The comparison between the mean length of uterosacral ligaments in the control and UUI groups was highly statistically significant (p < 0.001). The mean length of the right USL was 38 ± 11 mm, and the left USL was 35 ± 12 mm in the UUI group. In the control group, the mean length of the USL was 22 ± 9 mm on the right side and 18 ± 9 mm on the left side, along their craniocaudal extent. The highest inter-observer agreement was on the level of origin and insertion (image numbers), whereas the lowest agreement was on the anatomical site of origin and insertion of the USL in both the control and UUI groups.

CONCLUSIONS

The average length of USLs in patients with UUI is significantly longer than that in healthy continent women, indicating laxity. Our findings support the relationship between the laxity of the USL and UUI symptoms and have therapeutic implications.

Estrogen and Androgen Receptor Status in Uterosacral Ligaments of Women with Pelvic Organ Prolapse Stratified by the Pelvic Organ Prolapse Histology Quantification System

Menopause is a significant risk factor for pelvic organ prolapse (POP), suggesting that ovarian sex steroids play a major role in the etiology of the condition. POP results from failure of the uterine-cervix-vagina support structures, including the uterosacral ligament (USL). We previously identified consistent degenerative USL phenotypes that occur in POP and used their characteristics to develop a standardized POP Histologic Quantification System (POP-HQ). In this study, POP and matched control USL tissue was first segregated into the unique POP-HQ phenotypes, and specimens were then compared for estrogen receptor (ER) alpha (ERα), ERbeta (ERβ), the G-protein estrogen receptor (GPER), and androgen receptor (AR) content via immunohistochemical staining. ER and AR expression levels in the control USL tissues were indistinguishable from those observed in the POP-A phenotype, and partially overlapped with those of the POP-I phenotype. However, control-USL steroid receptor expression was statistically distinct from the POP-V phenotype. This difference was driven mainly by the increased expression of GPER and AR in smooth muscle, connective tissue, and endothelial cells, and increased expression of ERα in connective tissue. These findings support a multifactorial etiology for POP involving steroid signaling that contributes to altered smooth muscle, vasculature, and connective tissue content in the USL. Furthermore, these data support the concept that there are consistent and distinct degenerative processes that lead to POP and suggest that personalized approaches are needed that target specific cell and tissues in the pelvic floor to treat or prevent this complex condition.

Comparison of in vivo visco-hyperelastic properties of uterine suspensory tissue in women with and without pelvic organ prolapse

The uterine suspensory tissue (UST) complex includes the cardinal (CL) and uterosacral "ligaments" (USL), which are mesentery-like structures that play a role in resisting pelvic organ prolapse (POP). Since there is no information on the time-dependent material properties of the whole structure in situ and in vivo, we developed and tested an intraoperative technique to quantify in vivo whether there is a significant difference in visco-hyperelastic behavior of the CL and USL between women with and without POP. Thirteen women with POP (cases) and four controls scheduled for surgery were selected from an ongoing POP study. Immediately prior to surgery, a computer-controlled linear servo-actuator with a series force transducer applied a continuous, caudally directed traction force while simultaneously recording the resulting cervical displacement in the same direction. After applying an initial 1.1 N preload, a ramp rate of 4 mm/s was used to apply a maximum force of 17.8 N in three "ramp-and-hold" test trials. A simplified bilateral four-cable biomechanical model was used to identify the material behavior of each ligament. For this, the initial cross-section areas of the CL and USL were measured on 3-T magnetic resonance image-based 3D models from each subject. The time-dependent strain energy function of CL/USL was defined with a three-parameter hyperelastic Mooney-Rivlin material model and a two-term Prony series in relaxation form. When cases were compared with controls, the estimated time-dependent material constants of CL and USL did not differ significantly. These are the first measurements that compare the in vivo and in situ visco-hyperelastic response of the tissues comprising the CL and USL to loading in women with and without prolapse. Larger sample sizes would help improve the precision of intergroup differences.

Comparison of diagnostic values of transvaginal sonography with laparoscopic and histological results in the evaluation of uterosacral ligaments' involvement in endometriosis patients

BACKGROUND

Endometriosis is one of the most common gynecological disorders, which causes pain and reduces fertility. An accurate diagnostic technique would be helpful in the management of these patients preoperatively. The objective of this study was to do a comparative evaluation of uterosacral involvement in deep infiltrative endometriosis by transvaginal sonography (TVS) and laparoscopic biopsy.

METHODS

TVS and laparoscopy were done in all patients suspected to have endometriosis. TVS examination was carried out to identify endometriotic lesions, and in suspicious laparoscopic views, biopsy was done and laparoscopic findings were confirmed by pathologic report. Then, TVS and pathological findings in laparoscopy were compared and data analyzed by SPSS Version 23.

RESULTS

In our study on 80 patients, the mean age was 34.47 ± 5.94 (mean ± SD) years. Comparison of ultrasound with laparoscopic examinations showed that ultrasound as the gold standard method, has sensitivity, specificity, and positive and negative predictive values of 93%, 65%, and 87%, and 78.9%, respectively, while in the diagnosis of increased uterosacral ligament thickness showed 82%, 100%, and 100% and 6.66%, respectively. While in the diagnosis of nodules in the uterosacral ligament, 100% for all four parameters in the diagnosis of endometrioma in the ovaries, and 71%, 96.4%, and 97.3% and 64.2%, respectively, in the diagnosis of rectal, bladder, and ureteral involvement.

CONCLUSION

TVS can be used in the diagnosis of endometriosis by examining the increase in the thickness of the uterosacral ligament and the presence of hypoechoic nodules in it; also, this method demonstrates acceptable sensitivity and specificity in ovarian endometrioma.

Correlation between the expression of matrix metalloproteinase 9 and the expression of tissue inhibitor of metalloproteinase-1 of uterosacral ligament in uterine prolapse

Objective

This study aimed to analyze the correlation between the immunoexpression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TiMP1) in the uterosacral ligaments in patients with uterine prolapse.

Methods

This analytic-correlative cross-sectional study included 32 patients who were admitted at the Hasan Sadikin General Hospital from July to December 2013. Sixteen of the patients had uterine prolapse, while the rest did not. The patients underwent total hysterectomy, radical hysterectomy, or staging laparotomy. MMP-9 and TiMP1 expression in the uterosacral ligaments was measured via immunohistochemical staining. The median expression per field of view was calculated using a histoscore.

Results

MMP-9 expression in patients with uterine prolapse was found to be higher than that in the control group. Meanwhile, TiMP1 expression showed no significant difference between the groups. Spearman's analysis showed a moderate correlation between the expression of MMP-9 and uterine prolapse incidence (P=0.02), with a correlation coefficient of 0.574.

Conclusion

There is a moderate correlation between MMP-9 expression and the incidence of uterine prolapse. It can be considered one of the primary etiologies of uterine prolapse.

Transvaginal ultrasound features of normal uterosacral ligaments

OBJECTIVE

To show a step-by-step technique to assess normal uterosacral ligaments (USLs) during transvaginal ultrasound. Uterosacral ligaments represent the most common location of deep infiltrating endometriosis (DIE) in the posterior compartment and their involvement significantly increases the risk of ureteral lesions. The ultrasonographic diagnosis of DIE involving USLs is characterized by a wide range of accuracies described between studies, probably due to variations in the examination technique, quality of ultrasound equipment, and experience of the operators. Although described as a new classification system of DIE involving USLs, the technique for visualizing normal USLs has not yet been described.

DESIGN

Stepwise demonstration of the technique with narrated video footage.

SETTING

Academic tertiary hospital.

PATIENT(S)

The video shows a 33-year-old nulliparous woman scheduled for laparoscopic removal of a para-ovarian cyst of approximately 6 cm. Procedural steps were repeated and confirmed in another four patients submitted to laparoscopy for benign diseases (Table 1). Moreover, we here show the case of a 29-year-old woman with an isolated DIE nodule of the right USL with a comparison of laparoscopic and ultrasound findings. To better point out the technique applied in a clinical setting we show also cases of infiltrated USLs (Table 2) during the ultrasound scan in women scheduled for endometriosis surgery. Informed consent was obtained from all of the patients. The study protocol was approved by the local institutional Ethics Committee (580/2018/Oss/AOUBo).

INTERVENTION(S)

To understand correctly the right position of USLs we performed an ultrasound during a surgical procedure; in this way it was possible to recognize the area of interest while the surgeon filled the pouch of Douglas with fluid and highlighted the anatomical area with pliers. Uterosacral ligaments can be seen in the mid-sagittal and transverse view of the uterus.

MAIN OUTCOME MEASURE(S)

Description of appearance of normal USLs during transvaginal ultrasound.

RESULT(S)

Uterosacral ligaments, at transvaginal ultrasound, appear as hyperechoic stripes starting from the cervix and pointing laterally in a semi-horizontal direction.

CONCLUSION(S)

We provided a step-by-step technique (Table 3) that may be a useful tool to see accurately both the USLs at transvaginal ultrasound.

Evaluation of extracellular matrix protein expression and apoptosis in the uterosacral ligaments of patients with or without pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

This study aimed to compare the expression levels of extracellular matrix (ECM) and apoptosis proteins in the uterosacral ligament (USL) of patients with and without pelvic organ prolapse (POP).

METHODS

The USL were obtained from patients with POP-Q ≥ III (n = 35) and without POP (n = 20). Immunohistochemistry (IHC) staining and RT-qPCR were conducted to assess the protein and mRNA levels, respectively. The levels of type I collagen (COLI), type III collagen (COLIII), matrix metalloproteinase (MMP)1, MMP2, MMP9, tissue inhibitor of metalloproteinase (TIMP)1, TIMP2, estrogen receptor (ER)α, ERβ and apoptosis-related gene B cell lymphoma 2 (Bcl-2)-associated agonist of cell death (Bad) and Bcl-2-associated X (Bax) in the USL were analyzed.

RESULTS

The protein expression and mRNA levels of MMP2 and MMP9, mRNA levels of BAD and BAX, and protein expression of active cleaved-Caspase3 were significantly higher in the POP group. There were no evident differences in COLIII, MMP1 or ERβ expression at either the mRNA or protein level or in TIMP1, TIMP2 or Caspase3 by IHC between the two groups. However, obvious decreases in COLI and ERα were evident at both the mRNA and protein levels in the POP group, and the mRNA levels of TIMP1 and TIMP2 were also decreased compared to those of the control group.

CONCLUSION

ECM in the USL tissues of POP patients is remodeled compared with non-POP patients and is characterized by decreased synthesis and increased degradation of collagen; moreover, the levels of the main proteins involved in apoptosis are increased in POP tissue.

The role of transforming growth factor-ß (TGF-ß1) in postmenopausal women with pelvic organ prolapse: An immunohistochemical study

Objective

Aim of the study was to investigate the expression of transforming growth factor-β1 (TGF-β1), a key regulator of the extracellular matrix composition, in the uterosacral ligaments (USLs) of women with pelvic organ prolapse (POP) compared with controls. We hypothesized that the expression pattern of TGF-β1 differs between postmenopausal women with or without POP.

Methods

Under ethical approval, USL samples were obtained from postmenopausal women undergoing vaginal hysterectomy for stage two or greater pelvic organ prolapse (cases, n = 70) and from postmenopausal women without pelvic organ prolapse undergoing vaginal hysterectomy for benign indications (controls, n = 30). Immunohistochemical staining was performed from paraffin embedded tissue using anti-TGF-β1 antibodies. The expression of TGF-β1 was evaluated by the pathologist, who was blinded to all clinical data.

Results

The expression of TGF-ß1 was similar in patients with symptomatic POP (89 % positive) and in controls (90 % positive) without any signs of prolapse (p = 0.091). Age-adjusted analysis did not significantly alter these results. Regarding POP-Q stages, TGF-ß1 was significantly more frequently expressed in severe prolapse cases compared to moderate/mild cases (POP-Q stage IV versus POP-Q stage II and III; p = 0.001). No significant association could be detected between TGF-ß1 expression and age, BMI and parity in cases with POP (p > 0.05). As published previously, advanced patients’ age as well as early menopausal age remained independent risk factors associated with POP in multiple logistic regression analysis (p = 0.001; p = 0.02).

Conclusion

Although our study detected POP-Q stage related alterations in USL composition and TGF-ß1 expression, there was no significant difference in the expression of TGF-β1 in cases with or without prolapse.

The role of tenascin-X in the uterosacral ligaments of postmenopausal women with pelvic organ prolapse: an immunohistochemical study

INTRODUCTION AND HYPOTHESIS

Abnormalities of connective tissue structure or its repair mechanism may predispose women to pelvic organ prolapse (POP). We hypothesized that the expression of tenascin-X in the uterosacral ligament of postmenopausal women with symptomatic POP is increased compared with postmenopausal women without POP. Furthermore, we identified clinical risk factors associated with POP in our study population.

METHODS

We conducted a retrospective case-control study in which 33 postmenopausal women with symptomatic POP ≥ pelvic organ prolapse quantification system (POP-Q) stage II were matched with 33 postmenopausal women without POP. Studied tissue specimens were taken from hysterectomy specimens, and tenascin-X expression was investigated by immunohistochemistry. The immunohistochemical profile of the uterosacral connective tissue of cases and controls was compared.

RESULTS

Tenascin-X was expressed in 94% of POP cases and in 91% of controls. Our study failed to show any statistically significant differences in tenascin-X expression between women with and without POP (p = 0.64). However, tenascin-X was significantly more expressed in cases with severe prolapse (POP-Q stage IV) compared with moderate prolapse stages (POP-Q stage II and III) (p = 0.001). Advanced patient age as well as early menopausal age remained independent risk factors associated with POP in multiple logistic regression analysis (p = 0.001).

CONCLUSION

No difference could be demonstrated between tenascin-X expression in patients with or without POP. Tenascin-X does not seem to play a major role in the pathogenesis of POP in postmenopausal women.

Human

The uterosacral ligament (USL) is a major suspensory structure of the female pelvic floor, providing support to the cervix and/or upper vagina. It plays a pivotal role in surgical procedures for pelvic organ prolapse (POP) aimed at restoring apical support. Despite its important mechanical function, little is known about the mechanical properties of the USL due to the constraints associated with in vivo testing of human USL and the lack of validated large animal models that enable such investigations. In this study, we provide the first comparison of the mechanical properties of swine and human USLs. Preconditioning and pre-creep data up to a 2 N load and creep data under a 2 N load over 1200 s were obtained on swine (n = 9) and human (n = 9) USL specimens by performing planar equi-biaxial tensile tests and using the digital image correlation method. No differences in the peak strain during preconditioning tests, secant modulus of the pre-creep response, and strain at the end of creep tests were detected in the USLs from the two species along both axial loading directions (the main in vivo loading direction and the direction that is perpendicular to it). These findings suggest that the swine holds promise as large animal model for studying the mechanical role of the USL in apical vaginal support and treatment of POP.

Microarray gene expression analysis of uterosacral ligaments in uterine prolapse

OBJECTIVES

Pelvic organ prolapse (POP) is a major health problem that impairs the quality of life with a wide clinical spectrum. Since the uterosacral ligaments provide primary support for the uterus and the upper vagina, we hypothesize that the disruption of these ligaments may lead to a loss of support and eventually contribute to POP.

DESIGN AND METHODS

In this study, we therefore investigated whether there are any differences in the transcription profile of uterosacral ligaments in patients with POP when compared to those of the control samples. Seventeen women with POP and 8 non-POP controls undergoing hysterectomy for benign conditions were included in the study. Affymetrix® Gene Chip microarrays (Human Hu 133 plus 2.0) were used for whole genome gene expression profiling analysis.

RESULTS

There was 1 significantly down-regulated gene, NKX2-3 in patients with POP compared to the controls (p=4.28464e-013). KIF11 gene was found to be significantly down-regulated in patients with ≥3 deliveries compared to patients with <3 deliveries (p=0.0156237). UGT1A1 (p=2.43388e-005), SCARB1 (p=1.19001e-006) and NKX2-3 (p=2.17966e-013) genes were found to be significantly down-regulated in the premenopausal patients compared to the premenopausal controls. UGT1A1 gene was also found to be significantly down-regulated in the post menopausal patients compared to the postmenopausal controls (p=0.0005).

CONCLUSION

This study provides evidence for a significant down-regulation of the genes that take role in cell cycle, proliferation and embryonic development along with cell adhesion process on the development of POP for the first time.

Micro-structural and Biaxial Creep Properties of the Swine Uterosacral-Cardinal Ligament Complex

The uterosacral ligament and cardinal ligament (USL/CL) complex is the major suspensory tissue of the uterus, cervix, and vagina. This tissue is subjected primarily to bi-axial forces in-vivo that significantly alter its structure and dimension over time, compromising its support function and leading to pelvic floor disorders. In this study, we present the first rigorous characterization of the collagen fiber microstructure and creep properties of the swine USL/CL complex by using scanning electron microscopy and planar biaxial testing in combination with three-dimensional digital image correlation. Collagen fiber bundles were found to be arranged into layers. Although the fiber bundles were oriented in multiple directions, 80.8% of them were aligned within ±45[Formula: see text] to the main in-vivo loading direction. The straightness parameter, defined as the ratio of the end-to-end distance of a fiber bundle to its length, varied from 0.28 to 1.00, with 95.2% fiber bundles having a straightness parameter between 0.60 and 1.00. Under constant equi-biaxial loads of 2 and 4 N, the USL/CL complex exhibited significant creep both along the main in-vivo loading direction (the parallel direction) and along the direction perpendicular to it (the perpendicular direction). Specifically, over a 120-min period, the mean strain increased by 20-34[Formula: see text] in the parallel direction and 33-41[Formula: see text] in the perpendicular direction. However, there was no statistically significant difference in creep strains observed after 120 min between the parallel and perpendicular directions for either the 2 or 4 N load case. Creep proceeded slightly faster in the perpendicular direction under the equi-biaxial load of 2 N than under the equi-biaxial load of 4 N ([Formula: see text]). It proceeded significantly faster in the parallel direction under the equi-biaxial loads of 2 N than under the equi-biaxial loads of 4 N ([Formula: see text]). Overall, our findings contribute to a greater understanding of the biomaterial properties of the USL/CL complex that is needed for the development of new surgical reconstruction methods and mesh materials for pelvic floor disorders.

Comparative histology of mouse, rat, and human pelvic ligaments

INTRODUCTION AND HYPOTHESIS

The uterosacral (USL) and cardinal ligaments (CL) provide support to the uterus and pelvic organs, and the round ligaments (RL) maintain their position in the pelvis. In women with pelvic organ prolapse (POP), the connective tissue, smooth muscle, vasculature, and innervation of the pelvic support structures are altered. Rodents are commonly used animal models for POP research. However, the pelvic ligaments have not been defined in these animals. In this study, we hypothesized that the gross anatomy and histological composition of pelvic ligaments in rodents and humans are similar.

METHODS

We performed an extensive literature search for anatomical and histological descriptions of the pelvic support ligaments in rodents. We also performed anatomical dissections of the pelvis to define anatomical landmarks in relation to the ligaments. In addition, we identified the histological components of the pelvic ligaments and performed quantitative analysis of the smooth muscle bundles and connective tissue of the USL and RL.

RESULTS

The anatomy of the USL, CL, and RL and their anatomical landmarks are similar in mice, rats, and humans. All species contain the same cellular components and have similar histological architecture. However, the cervical portion of the mouse USL and RL contain more smooth muscle and less connective tissue compared with rat and human ligaments.

CONCLUSION

The pelvic support structures of rats and mice are anatomically and histologically similar to those of humans. We propose that both mice and rats are appropriate, cost-effective models for directed studies in POP research.

Histo-mechanical properties of the swine cardinal and uterosacral ligaments

The focus of this study was to determine the structural and mechanical properties of two major ligaments that support the uterus, cervix, and vagina: the cardinal ligament (CL) and the uterosacral ligament (USL). The adult swine was selected as animal model. Histological analysis was performed on longitudinal and cross sections of CL and USL specimens using Masson׳s trichrome and Verhoeff-van Giesson staining methods. Scanning electron microscopy was employed to visualize the through-thickness organization of the collagen fibers. Quasi-static uniaxial tests were conducted on specimens that were harvested from the CL/USL complex of a single swine. Dense connective tissue with a high content of elastin and collagen fibers was observed in the USL. Loose connective tissue with a considerable amount of smooth muscle cells and ground substance was detected in both the CL and USL. Collagen fibers, smooth muscle cells, blood vessels, and nerve fibers were arranged primarily in the plane of the ligaments. The USL was significantly stronger than the CL with higher ultimate stress and tangent modulus of the linear region of the stress-strain curve. Knowledge about the mechanical properties of the CL and USL will aid in the design of novel mesh materials, stretching routines, and surgical procedures for pelvic floor disorders.