Cervical alterations in pregnancy

Uterus and cervix anatomical changes and cervix stiffness evolution throughout pregnancy

The coordinated biomechanical performance, such as uterine stretch and cervical barrier function, within maternal reproductive tissues facilitates healthy human pregnancy and birth. Quantifying normal biomechanical function and detecting potentially detrimental biomechanical dysfunction (e.g., cervical insufficiency, uterine overdistention, premature rupture of membranes) is difficult, largely due to minimal data on the shape and size of maternal anatomy and material properties of tissue across gestation. This study quantitates key structural features of human pregnancy to fill this knowledge gap and facilitate three-dimensional modeling for biomechanical pregnancy simulations to deeply explore pregnancy and childbirth. These measurements include the longitudinal assessment of uterine and cervical dimensions, fetal weight, and cervical stiffness in 47 low-risk pregnancies at four time points during gestation (late first, middle second, late second, and middle third trimesters). The uterine and cervical size were measured via 2-dimensional ultrasound, and cervical stiffness was measured via cervical aspiration. Trends in uterine and cervical measurements were assessed as time-course slopes across pregnancy and between gestational time points, accounting for specific participants. Patient-specific computational solid models of the uterus and cervix, generated from the ultrasonic measurements, were used to estimate deformed uterocervical volume. Results show that for this low-risk cohort, the uterus grows fastest in the inferior-superior direction from the late first to middle second trimester and fastest in the anterior-posterior and left-right direction between the middle and late second trimester. Contemporaneously, the cervix softens and shortens. It softens fastest from the late first to the middle second trimester and shortens fastest between the late second and middle third trimester. Alongside the fetal weight estimated from ultrasonic measurements, this work presents holistic maternal and fetal patient-specific biomechanical measurements across gestation.

Contractions of the lower uterine segment during transvaginal ultrasound cervical length: incidence, significance, proper measurement, and management

An accurate transvaginal ultrasound cervical length is paramount to obtain the best prediction for preterm birth. Transvaginal ultrasound cervical length should be optimally obtained when a lower uterine segment contraction is not seen. For universal transvaginal ultrasound cervical length screening at approximately 20 weeks of gestation, the options are to do the transvaginal ultrasound soon after bladder void (lower uterine segment contractions present in 16%-43% of this approach) or to wait until the end of the anatomy scan (ideally within 30 minutes after bladder voiding) to decrease the chance of a lower uterine segment contraction. If the lower uterine segment contraction persists even after waiting up to 20 minutes or more, only the true transvaginal ultrasound cervical length should be reported. In particular, in patients with a previous spontaneous preterm birth, if the lower uterine segment contraction persists, the transvaginal ultrasound cervical length can be repeated in ≤7 days even in the presence of a normal (>25 mm) cervical length. Similar to a blood pressure cuff that must be of the right size for proper blood pressure measurement and a glucometer that must be properly calibrated, screening with transvaginal ultrasound cervical length should only be performed following a proper and standardized technique, including avoiding as much as feasible the presence of lower uterine segment contractions.

Pregnancy-induced remodeling of the murine reproductive tract: a longitudinal in vivo magnetic resonance imaging study

Mammalian pregnancy requires gradual yet extreme remodeling of the reproductive organs to support the growth of the embryos and their birth. After delivery, the reproductive organs return to their non-pregnant state. As pregnancy has traditionally been understudied, there are many unknowns pertaining to the mechanisms behind this remarkable remodeling and repair process which, when not successful, can lead to pregnancy-related complications such as maternal trauma, pre-term birth, and pelvic floor disorders. This study presents the first longitudinal imaging data that focuses on revealing anatomical alterations of the vagina, cervix, and uterine horns during pregnancy and postpartum using the mouse model. By utilizing advanced magnetic resonance imaging (MRI) technology, T1-weighted and T2-weighted images of the reproductive organs of three mice in their in vivo environment were collected at five time points: non-pregnant, mid-pregnant (gestation day: 9-10), late pregnant (gestation day: 16-17), postpartum (24-72 h after delivery) and three weeks postpartum. Measurements of the vagina, cervix, and uterine horns were taken by analyzing MRI segmentations of these organs. The cross-sectional diameter, length, and volume of the vagina increased in late pregnancy and then returned to non-pregnant values three weeks after delivery. The cross-sectional diameter of the cervix decreased at mid-pregnancy before increasing in late pregnancy. The volume of the cervix peaked at late pregnancy before shortening by 24-72 h postpartum. As expected, the uterus increased in cross-sectional diameter, length, and volume during pregnancy. The uterine horns decreased in size postpartum, ultimately returning to their average non-pregnant size three weeks postpartum. The newly developed methods for acquiring longitudinal in vivo MRI scans of the murine reproductive system can be extended to future studies that evaluate functional and morphological alterations of this system due to pathologies, interventions, and treatments.

Effects of Ureaplasma parvum infection in the exosome biogenesis-related proteins in ectocervical epithelial cells

Ureaplasma parvum is a mycoplasma commonly associated with female reproductive pathologies, such as preterm birth and infertility. It can survive intracellularly and utilize exosomes to propagate infection and its virulence factors. This study explored the differential protein composition of exosomes derived from normal and U. parvum-infected cells. We also investigated the impact of U. parvum on exosome biogenesis in ectocervical epithelial cells. Ectocervical epithelial (ECTO) cells were infected with U. parvum, and immunocytochemical staining was performed using U. parvum-specific marker multiple banded antigen (mba) and exosome marker CD9. NanoLC-MS/MS analysis was conducted to identify differentially expressed proteins in exosomes. Ingenuity Pathway Analysis (IPA) was performed to identify affected canonical pathways and biological functions associated with the protein cargo of exosomes. Western blot analysis of ECTO cells validated the proteomic findings in ECTO cells. U. parvum exhibited colonization of ECTO cells and colocalization with CD9-positive intraluminal vesicles. Proteomic analysis revealed decreased protein abundance and distinct protein profiles in exosomes derived from U. parvum-infected ECTO cells. Differentially expressed proteins were associated with clathrin-mediated endocytosis and various signaling pathways indicative of infection, inflammation, and cell death processes. Additionally, U. parvum infection altered proteins involved in exosome biogenesis. In ECTO cells, U. parvum infection significantly decreased clathrin, ALIX, CD9, and CD63 and significantly increased TSG101, Rab5, Rab35, and UGCG. These findings contribute to our understanding of the infection mechanism and shed light on the importance of exosome-mediated communication in the pathophysiology of diseases affecting the cervix, such as cervicitis and preterm birth.

Predictive factors for vaginal delivery by induction of labor in uncomplicated pregnancies at 40-41 gestational weeks: A Japanese prospective single-center cohort study

AIM

We investigated cervical parameters predictive of vaginal delivery in elective labor induction among women at 40-41 gestational weeks.

METHODS

This Japanese prospective single-center cohort study was conducted between July 2019 and June 2020. We enrolled women with an uncomplicated singleton pregnancy who underwent labor induction at 40-41 gestational weeks. We analyzed background characteristics and cervical parameters, including Bishop score, cervical length, posterior cervical angle, and changes in cervical parameters before and after cervical dilatation. The endpoint was the rate of vaginal delivery.

RESULTS

Of 142 eligible participants, all 24 multiparous women underwent vaginal delivery. Among the nulliparous women (n = 118), the following categories showed significantly higher rates of vaginal delivery: Bishop scores of ≥6 before and after dilatation, compared with Bishop score <6 (adjusted prevalence ratio (aPR) [95% confidence interval (CI)]; 1.58 [1.17-2.13] and 1.56 [1.13-2.14], respectively) and cervical length of <10 and 10-20 mm before dilation, compared with cervical length of >30 mm (aPR [95% CI]; 1.47 [1.00-2.15] and 2.13 [1.42-3.18], respectively). The posterior cervical angle and other background characteristics showed no significant associations. Furthermore, women with cervical lengths of ≥20 mm before and <20 mm after dilatation showed a higher rate of vaginal delivery, compared to cervical length of ≥20 mm even after dilatation (aPR [95% CI]; 1.95 [1.19-3.20]).

CONCLUSIONS

High Bishop score, short cervical length, and changes in cervical length with dilatation are potential independent predictors of vaginal delivery following elective labor induction in nulliparous women at 40-41 gestational weeks.

The Pathophysiology of Labor Dystocia: Theme with Variations

Abnormally prolonged labor, or labor dystocia, is a common complication of parturition. It is the indication for about half of unplanned cesarean deliveries in low-risk nulliparous women. Reducing the rate of unplanned cesarean birth in the USA has been a public health priority over the last two decades with limited success. Labor dystocia is a complex disorder due to multiple causes with a common clinical outcome of slow cervical dilation and fetal descent. A better understanding of the pathophysiologic mechanisms of labor dystocia could lead to new clinical opportunities to increase the rate of normal vaginal delivery, reduce cesarean birth rates, and improve maternal and neonatal health. We conducted a literature review of the causes and pathophysiologic mechanisms of labor dystocia. We summarize known mechanisms supported by clinical and experimental data and newer hypotheses with less supporting evidence. We review recent data on uterine preparation for labor, uterine contractility, cervical preparation for labor, maternal obesity, cephalopelvic disproportion, fetal malposition, intrauterine infection, and maternal stress. We also describe current clinical approaches to preventing and managing labor dystocia. The variation in pathophysiologic causes of labor dystocia probably limits the utility of current general treatment options. However, treatments targeting specific underlying etiologies could be more effective. We found that the pathophysiologic basis of labor dystocia is under-researched, offering wide opportunities for translational investigation of individualized labor management, particularly regarding uterine metabolism and fetal position. More precise diagnostic tools and individualized therapies for labor dystocia might lead to better outcomes. We conclude that additional knowledge of parturition physiology coupled with rigorous clinical evaluation of novel biologically directed treatments could improve obstetric quality of care.

Uterine macrophages as treatment targets for therapy of premature rupture of membranes by modified ADSC-EVs through a circRNA/miRNA/NF-κB pathway

Background

Circular RNA (circRNA) is a type of stable non-coding RNA that modifies macrophage inflammation by sponging micro RNAs (miRNAs), binding to RNA-binding proteins, and undergoing translation into peptides. Activated M1 phenotype macrophages secrete matrix metalloproteinases to participate in softening of the cervix uteri to promote vaginal delivery.

Methods

In this study, the premature rupture of membranes (PROM) mouse model was used to analyze the role of macrophages in this process. Profiling of circRNAs was performed using a competing endogenous RNA microarray, and their functions were elucidated in vitro. Meanwhile, adipose tissue-derived stem cell-secreted extracellular vesicles (EVs) were applied as a vehicle to transport small interfering RNAs (siRNAs) targeting the circRNAs to demonstrate their biological function in vivo.

Results

The miRNA miR-1931 is dependent on the nuclear factor kappa-B (NF-κB) pathway but negatively regulates its activation by targeting the NF-κB signaling transducer TRAF6 to prevent polarization of M1 macrophages and inhibit matrix metalloproteinase (MMP) secretion. The host gene of circRNA B4GALNT1, also an NF-κB pathway-dependent gene, circularizes to form circRNA_0002047, which sponges miR-1931 to maintain NF-κB pathway activation and MMP secretion in vitro. In the PROM model, EVs loaded with siRNAs targeting circRNAs demonstrated that the circRNAs reduced miR-1931 expression to maintain NF-κB pathway activation and MMP secretion for accelerating PROM in vivo.

Conclusions

Our data provide insights into understanding PROM pathogenesis and improving PROM treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01696-z.

Technology-free predictors of preterm birth in singleton women with threatened preterm labor: a prospective cohort study

Background

Prediction of preterm birth is still a challenge due to its multiple etiologies. This prospective cohort study aimed to determine the technology-free predictors of preterm birth in singleton women with threatened preterm labor.

Methods

This prospective cohort study was performed on 371 singleton women with gestational age of 23^+ 6 to 36^+ 4 weeks hospitalized for threatened preterm labor. The data were collected using a questionnaire including demographic characteristics, medical and maternal history, as well as the Perceived Stress Scale (PSS), the Multidimensional Scale of Perceived Social Support (MSPSS), and the WHO’s questionnaire of Violence against Women (VAW). The participants were followed-up until childbirth. The predictors were determined using multivariate logistic regression.

Results

Preterm birth occurred in 51% of women. Seven variables were determined as predictors; rupture of membranes [adjusted odds ratio 11.7, 95% confidence interval 5.4 to 25.6], cervical dilation [AOR 4.1, 95% CI 2.0 to 7.0], gravidity ≥6 [AOR 27.4, 95%CI 2.8 to 264.3], psychological violence during pregnancy [AOR 2.0, 95% CI 1.1 to 3.2], medical problems in pregnancy onset [AOR 1.7, 95% CI 1.1 to 2.8], vaginal bleeding/spotting [AOR 2.1, 95% CI 1.2 to 4.0] and woman age ≤ 19 [AOR 2.2, 95% CI 1.1 to 4.5]. The proportion of variance explained by all these factors was 33.6%.

Conclusions

The technology-free factors seems to have moderate power in preterm birth prediction in singleton pregnant women hospitalized for threatened preterm labor. However, these results are discoveries without verification or validation and need to be confirmed by generalizable studies.

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

Modeling ascending Ureaplasma parvum infection through the female reproductive tract using vagina-cervix-decidua-organ-on-a-chip and feto-maternal interface-organ-on-a-chip

Genital mycoplasmas can break the cervical barrier and cause intraamniotic infection and preterm birth. This study developed a six-chamber vagina-cervix-decidua-organ-on-a-chip (VCD-OOC) that recapitulates the female reproductive tract during pregnancy with culture chambers populated by vaginal epithelial cells, cervical epithelial and stromal cells, and decidual cells. Cells cultured in VCD-OOC were characterized by morphology and immunostaining for cell-specific markers. We transferred the media from the decidual cell chamber of the VCD-OOC to decidual cell chamber in feto-maternal interface organ-on-a-chip (FMi-OOC), which contains the fetal membrane layers. An ascending Ureaplasma parvum infection was created in VCD-OOC. U. parvum was monitored for 48 h post-infection with their cytotoxicity (LDH assay) and inflammatory effects (multiplex cytokine assay) in the cells tested. An ascending U. parvum infection model of PTB was developed using CD-1 mice. The cell morphology and expression of cell-specific markers in the VCD-OOC mimicked those seen in lower genital tract tissues. U. parvum reached the cervical epithelial cells and decidua within 48 h and did not cause cell death in VCD-OOC or FMi-OOC cells. U. parvum infection promoted minimal inflammation, while the combination of U. parvum and LPS promoted massive inflammation in the VCD-OOC and FMi-OOC cells. In the animal model, U. parvum vaginal inoculation of low-dose U. parvum did not result in PTB, and even a high dose had only some effects on PTB (20%). However, intra-amniotic injection of U. parvum resulted in 67% PTB. We report the colonization of U. parvum in various cell types; however, inconsistent, and low-grade inflammation across multiple cell types suggests poor immunogenicity induced by U. parvum.

Vaginal Nanoformulations for the Management of Preterm Birth

Preterm birth (PTB) is a leading cause of infant morbidity and mortality in the world. In 2020, 1 in 10 infants were born prematurely in the United States. The World Health Organization estimates that a total of 15 million infants are born prematurely every year. Current therapeutic interventions for PTB have had limited replicable success. Recent advancements in the field of nanomedicine have made it possible to utilize the vaginal administration route to effectively and locally deliver drugs to the female reproductive tract. Additionally, studies using murine models have provided important insights about the cervix as a gatekeeper for pregnancy and parturition. With these recent developments, the field of reproductive biology is on the cusp of a paradigm shift in the context of treating PTB. The present review focuses on the complexities associated with treating the condition and novel therapeutics that have produced promising results in preclinical studies.

Clinical application of cervical shear wave elastography in predicting the risk of preterm delivery in DCDA twin pregnancy

Background

Limited studies have used cervical shear wave elastography (SWE) as a tool to investigate the predictive effect of cervical changes on preterm delivery (PTD) in twin pregnancy. This study is aimed to predict the risk of PTD by cervical SWE in dichorionic diamniotic (DCDA) twin pregnancy.

Methods

A total of 138 women with dichorionic diamniotic (DCDA) twins were included in this prospective study. The mean SWE value of the cervix was obtained from the inner, middle and outer regions of the anterior and posterior cervical lips using a transvaginal ultrasound transducer and measured consecutively across three different gestations (20–23^+ 6 weeks, 24–27^+ 6 weeks, and 28–32 weeks). Follow-up was performed on all subjects, and we compared the mean SWE value between the PTD and term delivery (TD) groups.

Results

A total of 1656 cervical mean SWE data were collected for analysis. Among the 138 twin pregnant women, only 92 women completed the three elastography examinations; PTD occurred in 58.7% (54/92), and TD in 41.3% (38/92). The mean (SD) maternal age was 33.1 ± 4.1 years, and the mean (SD) body mass index was 21.1 ± 2.6 kg/m². As gestational age increased, the mean SWE value of each part of the cervix decreased. The cervical mean SWE value was lower in the preterm group than in the term group in all three gestations, except for the anterior cervical lip at 28–32 weeks. Receiver operating characteristics (ROC) curves showed the sensitivity of mean SWE value of the anterior cervical lip was 83.3% (95% CI, 70.7–92.1) with a specificity of 57.9% (95% CI, 40.8–73.7) for predicting PTD at a cutoff value of 7.94 kPa. The positive likelihood ratio (LR+) was 1.67 (95% CI, 1.19–2.34), and the negative likelihood ratio (LR–) was 0.33 (95% CI, 0.17–0.64).

Conclusions

There is a significant negative correlation between cervical stiffness and gestational age in DCDA twin pregnancy. SWE is a potential tool for assessing cervical stiffness and predicting PTD in DCDA twin pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04526-0.

Inflammatory response elicited by Ureaplasma parvum colonization in human cervical epithelial, stromal, and immune cells

Ureaplasma parvum is a commensal bacterium in the female reproductive tract but has been associated with pregnancy complications such as preterm prelabor rupture of membranes and preterm birth (PTB). However, the pathologic effects of U. parvum in the cervix, which prevents ascending infections during pregnancy, are still poorly understood. To determine the impact of U. parvum on the cervix, ectocervical (ecto) and endocervical (endo) epithelial and stromal cells were incubated with U. parvum. Macrophages were also tested as a proxy for cervical macrophages to determine the antigenicity of U. parvum. The effects of U. parvum, including influence on cell cycle and cell death, antimicrobial peptide (AMP) production, epithelial-to-mesenchymal transition (EMT), and inflammatory cytokine levels, were assessed. U. parvum colonized cervical epithelial and stromal cells 4 h post-infection. Like uninfected control, U. parvum neither inhibited cell cycle progression and nor caused cell death in cervical epithelial and stromal cells. U. parvum increased the production of the AMPs cathelicidin and human β-defensin 3 and exhibited weak signs of EMT evidenced by decreased cytokeratin 18 and increased vimentin expression in cervical epithelial cells. U. parvum induced a proinflammatory environment (cytokines) and increased MMP-9 in cervical epithelial cells but promoted pro- and anti-inflammatory response in cervical stromal cells and macrophages. U. parvum may colonize the cervical epithelial layer, but induction of AMPs and anti-inflammatory response may protect the cervix and may prevent ascending infections that can cause PTB. These findings suggest that U. parvum is a weak inducer of inflammation in the cervix.

Effect of Rubus idaeus L. Consumption During Pregnancy on Maternal Mice and Their Offspring

The trigger for human labor is a scientific mystery. This research examined Rubus idaeus (RI), commonly referred to as red raspberry, which is widely purported to be efficacious in promoting parturition processes and favorable birth outcomes. This randomized controlled trial sought to determine the influence of RI consumption during gestation on C57BL/6N Tac mice and their offspring. The aims of this study were to (1) determine differences in the length of gestation, gestational weight gain, and litter size where RI is consumed daily at varied strengths and (2) determine differences in offspring characteristics and behavior where maternal RI consumption occurred. Once paired, mice were randomly assigned to one of three groups: placebo (n = 10) receiving plain water, RI aqueous extract fluid of 1.78 mg/mL (n = 10), or RI aqueous extract fluid of 2.66 mg/mL (n = 10). All received the same standardized diet throughout gestation. Pregnant mice were weighed with chow intake and fluid consumption determined daily. Gestation length and litter size were recorded at the time of birth. Differences in offspring characteristics were also determined and included physical characteristics (weight, physical development) and neuromotor reflexes and behaviors (locomotive abilities, geotaxis reflex, cliff avoidance reflex, and swimming development). When compared with controls, high-dose RI ingestion resulted in shorter length of gestation and smaller litter size (P ≤ .05). There was also an increase in fluid consumption and a decrease in pup weights on postnatal day 4 and 5 with RI treatment (P ≤ .05). Altogether, results suggest that RI influences parturition and fecundity processes with transplacental exposure impacting offspring characteristics.

The impact of cervical conization size with subsequent cervical length changes on preterm birth rates in asymptomatic singleton pregnancies

The study aimed to explore the impact of cervical conization size (CCS) with subsequent cervical length (USCL) changes on preterm birth (PTB) rates in asymptomatic singleton pregnancies as compared to pregnancy outcomes in healthy women with an intact cervix (ICG), and to estimate PTB prevention efficiency in patients with a short cervix. Pregnancy outcomes in populations of similar age, ethnicity, residency, education and harmful habits having undergone cervical conization (CCG) were retrospectively analyzed and compared to ICG and cervical conization sub-populations adjusted by USCL during pregnancy (adequate cervical length vs. a short cervix) and a progesterone-only group (POG) vs. a progesterone-pessary group (PPG). Cervical conization was not associated with an increased PTB risk (CCG vs. ICG) when parameters of CCS and USCL were not adjusted (p = NS). A significantly higher proportion of parous women was observed in the CCG population than in the ICG (p = 0.0019). CCS turned out to be a key PTB risk during pregnancy, the larger CCS being associated with a short cervix (p = 0.0001) and higher PTB risks (p = 0.0001) with a notably increased PTB rate (p = 0.0001) in nulliparous women (p = 0.0022), whereas smaller CCS with adequate cervical length and a lower PTB rate was predominantly observed in women with prior parity. An initial equal USCL size was to be considerably elongated in women with adequate cervical length (p < 0.0001), and shortened in those with a short cervix (p < 0.0001). USCL assessment during pregnancy proved to be the PTB risk-predicting tool, with CCS supplementation apt to increase its diagnostic value. No substantial impact on pregnancy outcomes could be linked to any particular PTB prevention mode (POG or PPV). However, during pregnancy, the USCL changes relating to CCS proved to be more critical in pregnancy outcomes.

Cross talk: Trafficking and functional impact of maternal exosomes at the Feto-maternal Interface under normal and pathologic states

Fetal cell-derived exosomes promote inflammation in uterine and cervical cells to promote labor and delivery. However, the effect of maternal exosomes on fetal cells is still not known. We tested the hypothesis that cervical cells exposed to infectious and oxidative stress (OS) signals produce exosomes that can induce inflammation at the feto-maternal interface (FMi). Exosomes isolated from medium samples from human ectocervical epithelial cells (Ecto), endocervical epithelial cells (Endo), and cervical stromal cells (Stroma) in normal cell culture (control) or exposed to infection or OS conditions were characterized based on morphology, size, quantity, expression of tetraspanin markers, and cargo proteins. Human decidual, chorion trophoblast (CTC), chorion mesenchymal (CMC), amnion mesenchymal (AMC), and amnion epithelial cells (AEC) were treated with control, LPS-, or OS-treated cervical exosomes. ELISA for pro-inflammatory cytokines and progesterone was done to determine the recipient cells' inflammatory status. Ecto, endo, and stroma released ∼110 nm, cup-shaped exosomes. LPS and OS treatments did not affect exosome size; however, OS significantly increased the number of exosomes released by all cervical cells. Cervical exosomes were detected by fluorescence microscopy in each target cell after treatment. Exosomes from LPS- and CSE-treated cervical cells increased the inflammatory cytokine levels in the decidual cells, CMC, AMC, and AEC. LPS-treated stromal cell exosomes increased IL-6, IL-8, and progesterone in CTC. In conclusion, infection and OS can produce inflammatory cargo-enriched cervical exosomes that can destabilize FMi cells. However, the refractoriness of CTC to exosome treatments suggests a barrier function of the chorion at the FMi.

Trends, gaps, and future directions of research in cervical remodeling during pregnancy: a bibliometric analysis

PURPOSE

The cervix undergoes a dynamic remodeling process throughout pregnancy. Appropriate timing of cervical remodeling is essential in maintaining the fetus inside the uterus and ensuring cervical dilatation for safe delivery of the fetus at term. This study aims to determine the characteristics and trends of published articles in the field of cervical remodeling during pregnancy through a bibliometric analysis.

MATERIALS AND METHODS

A systematic review of the literature on cervical remodeling during pregnancy was performed on using the Scopus database from inception to 2020. The following information was obtained for each article: authors, year of publication, title, journal, institution, country, title, keywords, citation frequency, and relative citation ratio. The visualization of collaboration networks of countries and keywords related to cervical remodeling during pregnancy was conducted using VOSviewer software.

RESULTS

A total of 1979 bibliographic records were obtained from Scopus database. The number of publications increased in the 1980s and peaked in 2010. A total of 80 countries produced research in cervical remodeling during pregnancy. The USA contributed the greatest number of publications (n= 541), total citations (n= 11,971), and number of international collaborations (n= 28 countries). The American Journal of Obstetrics and Gynecology, Obstetrics and Gynecology, and BJOG: An International Journal of Obstetrics and Gynaecology are the top three contributors in this field in terms of number of publications and total citations. The Karolinska Institutet produced the greatest number of publications while UT Southwestern Medical Center was the most cited institution in this field. The topics of the top cited articles were studies regarding the role of collagen degradation in cervical remodeling during pregnancy; dynamics, anatomy, and physiology of cervical remodeling; and the use of misoprostol for cervical ripening and labor induction.

CONCLUSIONS

Our bibliometric analysis shows the trends and development, scientific impact, and collaboration in the field of cervical remodeling research. These results show the important discoveries in the past and provided new avenues for scientific and clinical investigations in the field.

Effects of a gestational level of estradiol on cellular transition, migration, and inflammation in cervical epithelial and stromal cells

PROBLEM

Estrogen (E2) is one of the main steroid hormones associated with pregnancy and parturition. High levels of E2 increase uterine contractions, promote fetal membrane weakening, and induce degradation of the cervical extracellular matrix (ECM). Current evidence supports the role of E2 in epithelial-to-mesenchymal transition (EMT) and inflammation in different cell types; however, its effects on the cellular components of the cervix are still unknown.

METHOD OF STUDY

In this study, we assessed the effects of gestational levels of E2 in: (a) the cellular transition of endocervical epithelial cells (EEC) and cervical stromal cells (CSC) in vitro using immunocytochemical staining and Western blot analyses for EMT markers (cytokeratin-18, E-cadherin, N-cadherin, SNAIL, and vimentin); (b) cell migration using in vitro scratch assays; (c) inflammatory cytokine (interleukin 1β and TNF-α) and MMP9 production under untreated and lipopolysaccharide (LPS)-treated conditions using immunoassays.

RESULTS

E2 treatment and co-treatment with LPS as a proxy for infection maintained the metastate of EEC (expression of both cytokeratin and vimentin) and the mesenchymal state of CSC. E2 delayed wound healing, which mimics the tissue remodeling process, in EEC and CSC. E2 led to persistently elevated levels of vimentin throughout the EEC wound healing process. E2 did not affect inflammatory cytokine production by EEC and CSC but increased MMP9 production by EEC.

CONCLUSION

Collectively, these results show that third trimester levels of E2 may permit localized inflammation, increase MMP-9 production, and cause an EMT-mediated impairment of the remodeling process in the cervix in vitro. These data suggest a potential contribution of E2 in cervical ripening.

Genetic landscape of preterm birth due to cervical insufficiency: Comprehensive gene analysis and patient next-generation sequencing data interpretation

Preterm delivery is both a traumatizing experience for the patient and a burden on the healthcare system. A condition distinguishable by its phenotype in prematurity is cervical insufficiency, where certain cases exhibit a strong genetic component. Despite genomic advancements, little is known about the genetics of human cervix remodeling during pregnancy. Using selected gene approaches, a few studies have demonstrated an association of common gene variants with cervical insufficiency. However, until now, no study has employed comprehensive methods to investigate this important subject matter. In this study, we asked: i) are there genes reliably linked to cervical insufficiency and, if so, what are their roles? and ii) what is the proportion of cases of non-syndromic cervical insufficiency attributable to these genetic variations? We performed next-generation sequencing on 21 patients with a clinical presentation of cervical insufficiency. To assist the sequencing data interpretation, we retrieved all known genes implicated in cervical functioning through a systematic literature analysis and additional gene searches. These genes were then classified according to their relation to the questions being posed by the study. Patients' sequence variants were filtered for pathogenicity and assigned a likelihood of being contributive to phenotype development. Gene extraction and analysis revealed 12 genes primarily linked to cervical insufficiency, the majority of which are known to cause collagenopathies. Ten patients carried disruptive variants potentially contributive to the development of non-syndromic cervical insufficiency. Pathway enrichment analysis of variant genes from our cohort revealed an increased variation burden in genes playing roles in tissue mechanical and biomechanical properties, i.e. collagen biosynthesis and cell-extracellular matrix communications. Consequently, the proposed idea of cervical insufficiency being a subtle form of collagenopathy, now strengthened by our genetic findings, might open up new opportunities for improved patient evaluation and management.

Dual excitation wavelength system for combined fingerprint and high wavenumber Raman spectroscopy

A fiber optic probe-based Raman spectroscopy system using a single laser module with two excitation wavelengths, at 680 and 785 nm, has been developed for measuring the fingerprint and high wavenumber regions using a single detector. This system is simpler and less expensive than previously reported configurations of combined fingerprint and high wavenumber Raman systems, and its probe-based implementation facilitates numerous in vivo applications. The high wavenumber region of the Raman spectrum ranges from 2800-3800 cm-1 and contains valuable information corresponding to the molecular vibrations of proteins, lipids, and water, which is complimentary to the biochemical signatures found in the fingerprint region (800-1800 cm-1), which probes DNA, lipids, and proteins. The efficacy of the system is demonstrated by tracking changes in water content in tissue-mimicking phantoms, where Voigtian decomposition of the high wavenumber water peak revealed a correlation between the water content and type of water-tissue interactions in the samples. This dual wavelength system was then used for in vivo assessment of cervical remodeling during mouse pregnancy, a physiologic process with known changes in tissue hydration. The system shows that Raman spectroscopy is sensitive to changes in collagen content in the fingerprint region and hydration state in the high wavenumber region, which was verified using an ex vivo comparison of wet and dry weight. Simultaneous fingerprint and high wavenumber Raman spectroscopy will allow precise in vivo quantification of tissue water content in the high wavenumber region, paired with the high biochemical specificity of the fingerprint region.