Effects of pelvic endometriosis and adenomyosis on ciliary beat frequency and muscular contractions in the human fallopian tube

A Review: Biomechanical Aspects of the Fallopian Tube Relevant to its Function in Fertility

The fallopian tube (FT) plays a crucial role in the reproductive process by providing an ideal biomechanical and biochemical environment for fertilization and early embryo development. Despite its importance, the biomechanical functions of the FT that originate from its morphological aspects, and ultrastructural aspects, as well as the mechanical properties of FT, have not been studied nor used sufficiently, which limits the understanding of fertilization, mechanotrasduction, and mechanobiology during embryo development, as well as the replication of the FT in laboratory settings for infertility treatments. This paper reviews and revives valuable information on human FT reported in medical literature in the past five decades relevant to the biomechanical aspects of FT. In this review, we summarized the current state of knowledge concerning the morphological, ultrastructural aspects, and mechanical properties of the human FT. We also investigate the potential arising from a thorough consideration of the biomechanical functions and exploring often neglected mechanical aspects. Our investigation encompasses both macroscopic measurements (such as length, diameter, and thickness) and microscopic measurements (including the height of epithelial cells, the percentage of ciliated cells, cilia structure, and ciliary beat frequency). Our primary focus has been on healthy women of reproductive age. We have examined various measurement techniques, encompassing conventional metrology, 2D histological data as well as new spatial measurement techniques such as micro-CT.

[Impact of Endometriosis on the Therapeutic Effect of Hysteroscopic Fallopian Tube Catheterization Combined With Laparoscopy in Infertile Patients With Proximal Tubal Obstruction]

Objective

To investigate the impact of endometriosis on the therapeutic effect of hysteroscopic fallopian tube catheterization combined with laparoscopy in infertile patients with proximal tubal obstruction.

Methods

We conducted a retrospective analysis of patients who underwent hysteroscopic fallopian tube catheterization combined with laparoscopy for infertility caused by proximal fallopian tube obstruction between January 19, 2016 and March 20, 2020 at the Department of Reproductive Endocrinology, West China Second Hospital, Sichuan University. During the operation, hydrotubation was performed to verify whether there was proximal tubal obstruction. Then, the patients were categorized into an endometriosis group and a non-endometriosis group according to whether their proximal tubal obstruction was combined with endometriosis. The baseline data were balanced by propensity score matching and the rate of successful surgical unblocking of proximal tubal obstruction in infertile patients by hysteroscopic fallopian tube catheterization combined with laparoscopy was calculated. Treating cases lost to follow-up in both groups as non-pregnant cases according to the principle of intention-to-treat analysis, we followed up the pregnancy outcomes after surgery. The primary indicators included overall successful surgical unblocking rate, clinical pregnancy rate, and spontaneous pregnancy rate, while the secondary indicators included live birth rate, miscarriage rate, ectopic pregnancy rate, and the mean time to spontaneous pregnancy after surgery. The primary indicators included overall successful surgical unblocking rate, clinical pregnancy rate, and spontaneous conception rate, while the secondary indicators included live birth rate, miscarriage rate, ectopic pregnancy rate, and the mean time to spontaneous pregnancy after surgery.

Results

After propensity score matching, 113 cases were included in each of the two groups, with the overall successful surgical unblocking rate being 72.6%. The successful surgical unblocking rate of patients in the endometriosis group was higher than that of the non-endometriosis group, with the difference being statistically significant (78.8% vs. 66.4%, P<0.05). A total of 38 patients were lost after follow-up matching. Postoperative follow-up was performed to date and, through intention-to-treat analysis, the spontaneous conception rate was found to be higher in the endometriosis group than that in the non-endometriosis group (44.2% vs. 30.1%, P<0.05), while the mean time to spontaneous pregnancy after surgery was shorter in the endometriosis group than that in the non-endometriosis group (46 months vs. 53 months, P<0.05). There was no significant difference in clinical pregnancy rate, live birth rate, miscarriage rate, and ectopic pregnancy rate between the endometriosis group and the non-endometriosis group ( P>0.05).

Conclusion

When infertility caused by proximal tubal obstruction is combined with endometriosis, performing hysteroscopic fallopian tube catheterization combined with laparoscopy contributes to the improvement of reproduction outcomes.

Oviduct-mimicking microfluidic chips decreased the ROS concentration in the in vitro fertilized embryos of CD-1 mice

BACKGROUND

The process of the assisted reproductive technology (ART) cycle is extremely complicated, and various factors in each step may influence the final clinical outcomes; thus, optimizing culture conditions for embryos is crucial in the ART cycle, particularly when the traditional petri-dish method remains unchanged for decades. In the current study, we intend to culture embryos in a dynamic environment on chips to optimize the embryo culture conditions.

METHODS

Multilayer soft lithography technology was utilized to establish a microfluidics-based oviduct. Mouse primary oviduct epithelial cells were identified by immunofluorescence staining and then loaded into the chip to coculture with the embryos. The development potential parameters of embryos on chips with cells, on chips without cells, and in drops were compared, as well as reactive oxygen species (ROS) in embryos.

RESULTS

There were no obvious differences regarding the fertilization rate, 4-Cell embryo rate, cleavage rate, high-quality embryo rate, or blastocyst formation rate. However, the intracellular ROS levels in 4-Cell stage embryos on chips with cells were statistically significantly lower than those in drops (P < 0.001). This organ-on-chip device allowed the probability of mammalian embryo culture in a microfluidic-based manner.

CONCLUSIONS

Our findings demonstrated that this novel oviduct-on-chip model may optimize embryo culture conditions by reducing intracellular ROS levels, which may be a competent alternative to the existing stable embryo culture system.

Molecular Mechanisms Underlying the Association between Endometriosis and Ectopic Pregnancy

Endometriosis is a common inflammatory disease characterized by the presence of endometrial cells outside the uterine cavity. It is estimated that it affects 10% of women of reproductive age. Its pathogenesis covers a wide range of abnormalities, including adhesion, proliferation, and cell signaling disturbances. It is associated with a significant deterioration in quality of life as a result of chronic pelvic pain and may also lead to infertility. One of the most serious complications of endometriosis is an ectopic pregnancy (EP). Currently, the exact mechanism explaining this phenomenon is unknown; therefore, there are no effective methods of prevention. It is assumed that the pathogenesis of EP is influenced by abnormalities in the contraction of the fallopian tube muscles, the mobility of the cilia, and in the fallopian microenvironment. Endometriosis can disrupt function on all three levels and thus contribute to the implantation of the embryo beyond the physiological site. This review takes into account aspects of the molecular mechanisms involved in the pathophysiology of endometriosis and EP, with particular emphasis on the similarities between them.

Distribution of tubal endometriosis: A 10-year retrospective study

AIM

To investigate the distribution of tubal endometriosis (EM) in the right and left sides and four parts of the fallopian tube.

METHODS

A retrospective, cross-sectional study was conducted on patients with tubal EM at the Fourth Affiliated Hospital of Guangxi Medical University from October 2011 to September 2021. Chi-square and binomial tests were used for analysis.

RESULTS

Thirty-four patients (53.97%) had tubal resection due to EM (EM group). Twenty-nine patients (46.03%) had tubal resection due to non-EM (non-EM group). Thirty-two patients (50.80%) had left fallopian tube EM, 21 (33.33%) had right fallopian tube EM, and 10 (15.87%) had bilateral fallopian tube EM, with significant differences among them (p = 0.000). In the EM group, 15 patients (44.12%) had left fallopian tube EM, 13 (38.23%) had right fallopian tube EM, and 6 (17.65%) had bilateral fallopian tube EM (p = 0.052). In the non-EM group, statistically different (p = 0.001) diagnoses of left fallopian tube EM, right fallopian tube EM, and bilateral fallopian tube EM were 17 (58.62%), 8 (27.59%), and 4 (13.79%), respectively. In the EM group, 18 patients (52.94%) were in the ampullary region; 16 (47.06%) were in the nonampullary region (p = 0.864). In the non-EM group, 22 cases (75.86%) were in the ampullary region and 7 (24.14%) were in the nonampullary region, with a significant difference between them (p = 0.008).

CONCLUSIONS

The incidence of left fallopian tube EM was higher than that of right and bilateral fallopian tube EM. The incidence of tubal ampullary EM was higher than that of nonampullary region.

Tubal Endometriosis: From Bench to Bedside, A Scoping Review

Tubal endometriosis (EM) refers to the detection of ectopic endometrial implants on tubes. It may cause a significant defect of the tubes, translating into dysmenorrhea, pelvic pain, and infertility. We aimed to evaluate the disease characteristics, prevalence, histopathological findings and genetic profile of patients with tubal EM. A thorough search of three electronic databases was performed for studies that presented outcomes of patients with tubal EM. Thirteen studies (four observational, seven case reports, two genetic) were considered eligible for inclusion. The prevalence of tubal EM ranged from 6.9% to 69%. The predominant symptoms for referral of patients were infertility and abdominal pain. Women of reproductive age underwent salpingectomy for the management of the disease. Only one case of malignant transformation was recorded in a 60-year-old patient. The prevalence of tubal EM ranges depending on the indication for surgery, the presence of concomitant pelvic EM and the type of diagnosis and treatment. Further, more extensive, larger studies are warranted to evaluate the impact of tubal EM in the progression and prognosis of EM, the effect of salpingectomy in the improvement of disease-related symptoms and to designate the group of patients that could benefit from risk-reducing salpingectomy based on the risk of developing ovarian malignancy.

Cystic ovary disease impairs transport speed, smooth muscle contraction, and epithelial ion transport in the bovine oviduct

Cystic ovary disease (COD) is a common cause of bovine infertility but the impact of this disease on the oviduct is unknown. The aim of this study was to analyze the effects of COD on particle transport speed (PTS), ciliary beat frequency, myosalpinx contraction, and epithelial ion transport. Oviducts were obtained from cows affected by COD and compared with those of healthy, mid-diestrus cows. PTS and CBF were examined using live-cell imaging. Smooth muscle contraction and epithelial ion transport were investigated using organ baths and Ussing chambers. Our results showed that muscarinic receptors are involved in cholinergic signaling in the oviduct and that forskolin-induced cyclic AMP production is involved in active ion transport in the oviductal epithelium. Oviducts from cows with luteal cysts revealed significantly decreased PTS (p = 0.02). Further to that, in the oviducts of COD cows, the cholinergic regulation of smooth muscle contractions and active epithelial ion transport were significantly diminished (p < 0.0001). These results imply that in COD cows, oviductal transport is compromised by decreased fluid flow speed and reduced cholinergic regulation of smooth muscle contraction and ion transport. This knowledge contributes to a more comprehensive understanding of COD supporting the development of novel therapeutic concepts for infertility treatment.

Fallopian tube endometriosis in women undergoing operative video laparoscopy and its clinical implications

OBJECTIVE

To determine the incidence of fallopian tube endometriosis in patients undergoing laparoscopic surgery with a preoperative diagnosis of endometriosis, pelvic pain, infertility, or cystic adnexal mass.

DESIGN

Retrospective cross-sectional study.

SETTING

Gynecologic oncology and minimally invasive surgery practice.

PATIENT(S)

All patients who underwent surgery for endometriosis from July 2015 to June 2018 were included. Exclusion criteria were age ≥55 years, diagnosis of cancer, laparotomy, previous bilateral salpingectomy, and preoperative diagnosis other than endometriosis, pelvic pain, infertility, or cystic adnexal mass.

INTERVENTION(S)

Subjects were divided by those who did and those who did not have a salpingectomy at the time of surgery.

MAIN OUTCOME MEASURE(S)

Diagnosis of tubal endometriosis was based on macroscopic evidence of endometrial implants on the fallopian tube(s) noted within the operative report and microscopic evidence of endometriosis noted within the pathology report.

RESULT(S)

A total of 444 surgeries were performed and 185 met the study criteria. Among those, 153 (82.7%) had histologically diagnosed endometriosis within the abdominopelvic cavity. The incidence of tubal endometriosis was 11%-12% macroscopically and 42.5% microscopically after salpingectomy. Patients with tubal endometriosis were more likely to have severe disease.

CONCLUSION(S)

Among patients with endometriosis, the incidence of microscopic tubal endometriosis was significantly greater than that of macroscopic disease.

Endometriosis and the Fallopian Tubes: Theories of Origin and Clinical Implications

Endometriosis is a common, oestrogen driven chronic condition, where endometrium-like epithelial and stromal cells exist in ectopic sites. At present, no curative treatments are available and the existing evidence for disease progression is conflicting. The pathogenesis is still unknown and evidently complex, as mechanisms of initiation may depend on the anatomical distribution of endometriotic lesions. However, amongst the numerous theories and plethora of mechanisms, contributions of the fallopian tubes (FT) to endometriosis are rarely discussed. The FT are implicated in all endometriosis associated symptomatology and clinical consequences; they may contribute to the origin of endometriotic tissue, determine the sites for ectopic lesion establishment and act as conduits for the spread of proinflammatory media. Here, we examine the available evidence for the contribution of the human FT to the origin, pathogenesis and symptoms/clinical consequences of endometriosis. We also examine the broader topic linking endometriosis and the FT epithelium to the genesis of ovarian epithelial cancers. Further studies elucidating the distinct functional and phenotypical characteristics of FT mucosa may allow the development of novel treatment strategies for endometriosis that are potentially curative.

Genome-wide profiling of miRNA expression patterns in tubal endometriosis

MicroRNA (miRNA) expression profiles in tubal endometriosis (EM) are still poorly understood. In this study, we analyzed the differential expression of miRNAs and the related gene networks and signaling pathways in tubal EM. Four tubal epithelium samples from tubal EM patients and five normal tubal epithelium samples from uterine leiomyoma patients were collected for miRNA microarray. Bioinformatics analyses, including Ingenuity Pathway Analysis (IPA), Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, were performed. Quantitative real-time polymerase chain reaction (qRT-PCR) validation of five miRNAs was performed in six tubal epithelium samples from tubal EM and six from control. A total of 17 significantly differentially expressed miRNAs and 4343 potential miRNA-target genes involved in tubal EM were identified (fold change >1.5 and FDR-adjusted P value <0.05). IPA indicated connections between miRNAs, target genes and other gynecological diseases like endometrial carcinoma. GO and KEGG analysis revealed that most of the identified genes were involved in the mTOR signaling pathway, SNARE interactions in vesicular transport and endocytosis. We constructed an miRNA-gene-disease network using target gene prediction. Functional analysis showed that the mTOR pathway was connected closely to tubal EM. Our results demonstrate for the first time the differentially expressed miRNAs and the related signal pathways involved in the pathogenesis of tubal EM which contribute to elucidating the pathogenic mechanism of tubal EM-related infertility.

Integrated analysis of mRNA and protein expression profiling in tubal endometriosis

Tubal endometriosis (tubal EM) is a subtype of endometriosis (EM) associated with fallopian tube impairments and infertility. Since the molecular mechanism underlying tubal EM is not clear, we assume that an aberrant transcriptome of fallopian tube epithelium and microenvironment changes caused by cytokines in tubal fluid are possible causes. The aim of this study was to identify potential hub mRNAs/proteins of tubal EM through integrated transcriptomic and proteomic analyses and to elucidate significant pathways, cellular functions, and interaction networks during the initiation and progression of tubal EM. We obtained human fallopian tube epithelium and tubal fluid samples from patients with and without tubal EM. Tubal epithelia were analyzed using microarray, and tubal fluid was analyzed using quantitative label-free LC-MS/MS. We identified differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) and determined common mRNAs/protein. We observed 35 commonly deregulated mRNAs/proteins, and IPA indicated that cellular movement, inflammatory response, and immune cell trafficking were significantly activated during the pathogenesis of tubal EM. We also identified acute phase response signaling pathway activation as a unique pathogenesis signature of tubal EM. Our results demonstrate that an integrated analysis of the transcriptome and proteome has the potential to reveal novel disease mechanisms at a molecular level.

Is tubal endometriosis an asymmetric disease? A 17-year retrospective study

PURPOSE

To investigate whether there are left-right asymmetries in tubal endometriosis and the factors affecting this predisposition.

METHODS

Women who underwent salpingectomy for gynecological diseases and were diagnosed with tubal endometriosis between January 2002 and July 2019 were included in the study. The frequencies of left and right tubal endometriosis were compared with the expected 50% using a binominal test. The demographic characteristics and presence of ovarian endometrioid cysts, adenomyosis, and hydrosalpinx were also analyzed.

RESULTS

During the study period of more than 17 years, 305 women were diagnosed with tubal endometriosis. The distribution of tubal endometriosis in the left or right fallopian tubes was analyzed. Tubal endometriosis was found in the left fallopian tube in 168 (55.08%) women, in the right fallopian tube in 93 (30.49%), and bilaterally in 44 (14.43%). Left unilateral tubal endometriosis was found most frequently (64.37%, 168/261), and its incidence was significantly higher than 50% (P < 0.001, binominal test). Furthermore, the frequency of left ovarian endometrioid cysts (58.82%) was higher than that of right ovarian endometrioid cysts (41.18%) (P < 0.001, binominal test).

CONCLUSION

Our study confirms that tubal endometriosis is a left-side asymmetric disease, and this predisposition is highly consistent with ovarian endometrioid cysts, which supports the transplantation theory of the origin of endometriosis.

Reassessment of prevalence of tubal endometriosis, and its associated clinicopathologic features and risk factors in premenopausal women received salpingectomy

Introduction

To reassess the prevalence of fallopian tube endometriosis (EM), and its associated clinicopathologic characteristics and risk factors.

Methods

Cross-sectional study was conducted from June 2016 to August 2017. Unpregnant premenopausal women who underwent unilateral or bilateral salpingectomy due to gynecologic diseases were recruited. Patient clinical data and fallopian tube specimens were collected. Hematoxylin-eosin (H&E) staining and CD10 immunohistochemistry were used to diagnose tubal EM.

Results

Tubal EM prevalence was 14.48% (161/1112, 95% confidence interval [CI] 12.41%–16.55%). Prevalence of tubal EM in patients with EM was 37.37% (95%CI 30.58%–44.17%) which is higher in patients without EM (9.52%, 95%CI 7.61%–11.42%) and even higher in those with multi-organ EM (43.94%, 95%CI 35.36%–52.52%). At unilateral or bilateral salpingectomy, tubal EM was more likely located in the left fallopian tube (52.17%) than the right one (40.37%) and presence of hydrosalpinx/ hematosalpinx increased in women with tubal EM than without tubal EM (43.47% versus 23.79%). With increasing severity of pelvic EM (r = 0.26, P<10⁻⁴) and adhesion (r = 0.25, P<10⁻⁴), the tubal EM prevalence also increased. Pathological examination found that tubal EM was more likely located in the mucosa of the proximal tube with significantly more surrounding inflammation and fibrotic lesions than the serosa/sub-serosa in the distal tube (r = 0.90, P<10⁻⁴). Multivariate analysis showed that abnormal uterine bleeding (AUB) (AOR = 3.10), previous EM surgery (AOR = 4.22) and tubal ligation (AOR = 2.33) were risk factors for tubal EM.

Conclusions

These data provide clinicians with important information that the prevalence of tubal EM among premenopausal unpregnant patients was higher than previous investigators, especially higher among women with EM diseases. Identifying its clinicopathologic characteristics and predictors may facilitate clinical decision making.

Exploring the Role of Fallopian Ciliated Cells in the Pathogenesis of High-Grade Serous Ovarian Cancer

High-grade serous epithelial ovarian cancer (HGSOC) is the fifth leading cause of cancer death in women and the first among gynecological malignancies. Despite an initial response to standard chemotherapy, most HGSOC patients relapse. To improve treatment options, we must continue investigating tumor biology. Tumor characteristics (e.g., risk factors and epidemiology) are valuable clues to accomplish this task. The two most frequent risk factors for HGSOC are the lifetime number of ovulations, which is associated with increased oxidative stress in the pelvic area caused by ovulation fluid, and a positive family history due to genetic factors. In the attempt to identify novel genetic factors (i.e., genes) associated with HGSOC, we observed that several genes in linkage with HGSOC are expressed in the ciliated cells of the fallopian tube. This finding made us hypothesize that ciliated cells, despite not being the cell of origin for HGSOC, may take part in HGSOC tumor initiation. Specifically, malfunction of the ciliary beat impairs the laminar fluid flow above the fallopian tube epithelia, thus likely reducing the clearance of oxidative stress caused by follicular fluid. Herein, we review the up-to-date findings dealing with HGSOC predisposition with the hypothesis that fallopian ciliated cells take part in HGSOC onset. Finally, we review the up-to-date literature concerning genes that are located in genomic loci associated with epithelial ovarian cancer (EOC) predisposition that are expressed by the fallopian ciliated cells.