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Kurt I, Kulhan M, AlAshqar A, Borahay MA. Uterine Collagen Cross-Linking: Biology, Role in Disorders, and Therapeutic Implications. Reprod Sci 2024; 31:645-660. [PMID: 37907804 DOI: 10.1007/s43032-023-01386-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/13/2023] [Indexed: 11/02/2023]
Abstract
Collagen is an essential constituent of the uterine extracellular matrix that provides biomechanical strength, resilience, structural integrity, and the tensile properties necessary for the normal functioning of the uterus. Cross-linking is a fundamental step in collagen biosynthesis and is critical for its normal biophysical properties. This step occurs enzymatically via lysyl oxidase (LOX) or non-enzymatically with the production of advanced glycation end-products (AGEs). Cross-links found in uterine tissue include the reducible dehydro-dihydroxylysinonorleucine (deH-DHLNL), dehydro-hydroxylysinonorleucine (deH-HLNL), and histidinohydroxymerodesmosine (HHMD); and the non-reducible pyridinoline (PYD), deoxy-pyridinoline (DPD); and a trace of pentosidine (PEN). Collagen cross-links are instrumental for uterine tissue integrity and the continuation of a healthy pregnancy. Decreased cervical cross-link density is observed in preterm birth, whereas increased tissue stiffness caused by increased cross-link density is a pathogenic feature of uterine fibroids. AGEs disrupt embryo development, decidualization, implantation, and trophoblast invasion. Uterine collagen cross-linking regulators include steroid hormones, such as progesterone and estrogen, prostaglandins, proteoglycans, metalloproteinases, lysyl oxidases, nitric oxide, nicotine, and vitamin D. Thus, uterine collagen cross-linking presents an opportunity to design therapeutic targets and warrants further investigation in common uterine disorders, such as uterine fibroids, cervical insufficiency, preterm birth, dystocia, endometriosis, and adenomyosis.
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Affiliation(s)
- Irem Kurt
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Selcuk University Faculty of Medicine, 42000, Konya, Turkey
| | - Mehmet Kulhan
- Department of Gynecology and Obstetrics, Selcuk University Faculty of Medicine, 42000, Konya, Turkey
| | - Abdelrahman AlAshqar
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Mostafa A Borahay
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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2
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Yang X, Ding Y, Mei J, Xiong W, Wang J, Huang Z, Li R. Second-Trimester Cervical Shear Wave Elastography Combined With Cervical Length for the Prediction of Spontaneous Preterm Birth. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:820-829. [PMID: 35272890 DOI: 10.1016/j.ultrasmedbio.2022.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 12/06/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The goal of this study was to explore the value of shear wave elastography (SWE) combined with cervical length (CL) in the prediction of spontaneous preterm birth (sPTB) between 18 and 24 weeks of gestation. In this study, SWE was used to evaluate four regions of the cervix: the external and anterior lip (region A1), the external and posterior lip (region A2), the internal and anterior lip (region A3) and the internal and posterior lip (region A4). The cervical Young's modulus (YM) was compared between women who spontaneously delivered prematurely (<37 wk) and those who delivered full term. Finally, the predictive power of SWE was evaluated using receiver operating characteristic analysis. Overall, 773 patients were included in this study, of whom 60 (7.8%) had a sPTB. In the univariate analysis, prior sPTB, history of spontaneous abortion, history of cervical surgery, CL and YM at the anterior portion of both the internal and external os and the posterior portion of the internal os were associated with sPTB (p < 0.05). Multiple regression analyses were performed to develop the prediction probability for sPTB. YM and CL were independent predictors of sPTB in asymptomatic women, and the combination of YM and CL improved the ability to predict sPTB (area under the receiver operating characteristic curve = 0.98, 95% confidence interval: 0.97-0.99, p < 0.001). The interventions had relatively little impact on the outcome indicators measured. Cervical YM added to the CL may improve the predictive performance of second-trimester transvaginal ultrasound for sPTB.
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Affiliation(s)
- Xiaofeng Yang
- First Affiliate Hospital of Jinan University, Guangzhou, China
| | - Yuzhen Ding
- First Affiliate Hospital of Jinan University, Guangzhou, China
| | - Jie Mei
- Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Wen Xiong
- Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Jingyun Wang
- First Affiliate Hospital of Jinan University, Guangzhou, China
| | - Zhengrui Huang
- First Affiliate Hospital of Jinan University, Guangzhou, China
| | - Ruiman Li
- First Affiliate Hospital of Jinan University, Guangzhou, China.
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Jayyosi C, Lee N, Madhukaran SP, Nallasamy S, Mahendroo M, Myers K. The swelling behavior of the mouse cervix: Changing kinetics with osmolarity and the role of hyaluronan in pregnancy. Acta Biomater 2021; 135:414-424. [PMID: 34411755 DOI: 10.1016/j.actbio.2021.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 11/29/2022]
Abstract
The cervical remodeling process during pregnancy is characterized by progressive compositional and structural changes in the tissues extra-cellular matrix (ECM). Appropriately timed remodeling is critical for healthy gestation and prevention of premature cervical softening leading to preterm birth (PTB). Modification of the ECM glycosaminoglycans (GAGs) content with advancing pregnancy, especially the non-sulfated GAG hyaluronan (HA), is a fundamental change associated with cervical remodeling. While GAGs have numerous physiological roles, the mechanical consequence of evolving GAG content on cervical structure-function behavior remains an open question. Additionally, an understanding of cervical swelling properties, postulated to be regulated in part by GAGs, is required for the appropriate definition of a reference configuration for mechanical tests and to enhance biological understanding. To investigate cervical swelling, osmotic loading tests are conducted on isolated wild type mouse cervices throughout pregnancy. These tests are performed in various osmolarity solutions to assess the influence of the media on swelling kinetics. A genetically altered strain of mice with depletion of cervical HA is also tested to elucidate the contribution of HA to tissue swelling. Results show ex vivo cervical swelling is significant with volume changes ranging from 20 to 100% after 3h of free swelling. The swelling kinetics depend highly on osmolarity of the media and is altered with advancing pregnancy. The contribution of HA to swelling is only significant in hypo-osmotic solution when HA cervical content is high at the end of pregnancy. In summary, it is critical to account for swelling deformation mechanisms after excision in mechanical experiments. STATEMENT OF SIGNIFICANCE: The cervical extracellular matrix (ECM) undergoes drastic changes to fulfill the functional change of the cervix during pregnancy. Inappropriate timing for this transformation can result in preterm birth, a severe clinical challenge. One of the fundamental changes of the cervical ECM is the significant modification of the glycosaminoglycan content, especially hyaluronan (HA), which is thought to contribute significantly to the swelling and mechanical properties of the cervix. This study aims to measure the swelling kinetics of cervical tissue during pregnancy and to investigate the role of HA in these swelling tendencies. Results show the significant swelling of cervical tissue, which evolves as pregnancy progresses, highlighting a key material property feature of the remodeled cervix. Using a mouse strain with a cervical HA depletion, this work shows HA contributes to the swelling trends of late-term cervical tissue, in a hypo-osmotic solution.
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Affiliation(s)
- C Jayyosi
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - N Lee
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - S P Madhukaran
- Department of Obstetrics and Gynecology and Cecil H. and Ida Green Center for Reproductive Biological Science, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - S Nallasamy
- Department of Obstetrics and Gynecology and Cecil H. and Ida Green Center for Reproductive Biological Science, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - M Mahendroo
- Department of Obstetrics and Gynecology and Cecil H. and Ida Green Center for Reproductive Biological Science, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - K Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
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Ahn KH, Kim HY, Cho GJ, Hong SC, Oh MJ, Kim HJ. Role of sex hormones in cervical changes in a cervical excision-related preterm delivery mouse model. J OBSTET GYNAECOL 2020; 41:138-146. [PMID: 32157933 DOI: 10.1080/01443615.2020.1727868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Progesterone and oestrogen play important roles during parturition; however, their roles in the uterine cervix during preterm labour and delivery are unknown. We evaluated the serum progesterone and oestrogen levels and changes in their receptors (PR and ER) in the cervix in a cervical excision-associated preterm delivery mouse model. Adult female C57BL/6 mice were divided into four groups: sham, cervical excision (Ex), lipopolysaccharide (LPS) and Ex + LPS. Mating was permitted at 3 weeks post-Ex. On gestation day 16, mice were administered LPS intrauterine (100 µg/100 µL/mouse) or physiological saline (100 µL) via laparotomy. Uterine cervices and blood were sampled immediately postpartum. As a result, epithelial PR and muscular ERα were down- and upregulated, respectively, in the proximal cervix in Ex + LPS group compared to in the sham group. These results indicate that unique sex hormone effects are exerted on the uterine cervix during cervical excision-associated spontaneous preterm labour and delivery.Impact statementWhat is already known on this subject? Preterm and term parturition require the withdrawal of progesterone and the activation of oestrogen in the uterine body and systemic levels. However, we have little understanding of the role of the sex hormones in the uterine cervix.What do the results of this study add? Increased ERα-to-PR expression ratio in the proximal cervix was associated with preterm labour and delivery. ERα expression in the smooth muscle layer of the proximal cervix was higher and PR expression in the proximal cervix epithelium was lower during preterm labour and delivery.What are the implications of these findings for clinical practice and/or further research? This study revealed the differences between the roles of sex hormones and their receptors in epithelial and muscle layers of proximal and distal cervices in preterm labour and delivery.
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Affiliation(s)
- Ki Hoon Ahn
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
| | - Hee Youn Kim
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
| | - Geum Joon Cho
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
| | - Soon Cheol Hong
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
| | - Min Jeong Oh
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
| | - Hai Joong Kim
- Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, South Korea
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5
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Abstract
The cervix is the essential gatekeeper for birth. Incomplete cervix remodeling contributes to problems with delivery at or post-term while preterm birth is a major factor in perinatal morbidity and mortality in newborns. Lack of cervix biopsies from women during the period preceding term or preterm birth have led to use of rodent models to advanced understanding of the mechanism for prepartum cervix remodeling. The critical transition from a soft cervix to a compliant prepartum lower uterine segment has only recently been recognized to occur in various mammalian species when progesterone in circulation is at or near the peak of pregnancy in preparation for birth. In rodents, characterization of ripening resembles an inflammatory process with a temporal coincidence of decreased density of cell nuclei, decline in cross-linked extracellular collagen, and increased presence of macrophages in the cervix. Although a role for inflammation in parturition and cervix remodeling is not a new concept, a comprehensive examination of literature in this review reveals that many conclusions are drawn from comparisons before and after ripening has occurred, not during the process. The present review focuses on essential phenotypes and functions of resident myeloid and possibly other immune cells to bridge the gap with evidence that specific biomarkers may assess the progress of ripening both at term and with preterm birth. Moreover, use of endpoints to determine the effectiveness of various therapeutic approaches to forestall remodeling and reduce risks for preterm birth, or facilitate ripening to promote parturition will improve the postpartum well-being of mothers and newborns.
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Affiliation(s)
- Steven M Yellon
- Department of Basic Sciences, Longo Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
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6
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Pandey M, Awasthi S. Role of MMP-1, MMP-8 and MMP-9 gene polymorphisms in preterm birth. J Genet 2020; 99:2. [PMID: 32089521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Novel approaches to preterm births are underway building upon our prior discoveries and probing into unknown discovery pathways. The recent findings showed a high affinity of MMP-9 in serum and its polymorphisms for preterm birth. This study, which is a hospital-based case-control study, aims to investigate the association of MMP-1, MMP-8 and MMP-9 polymorphisms, and levels of MMP-9 in preterm birth. Increased level of MMP-9 was reported in cases as compared to control. The significant association of MMP-9 (-1562) CT (P = 0.001; OR = 1.44(CI = 0.97-2.14)) and TTgenotype (P = 0.05;OR = 2.6 (CI = 1.46-4.69)) were reported in preterm birth. Our findings suggest that the MMP-9 plays an important role in contributing preterm labour and this can be used as a diagnostic tool during pregnancy.
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Affiliation(s)
- Monika Pandey
- Department of Pediatrics, King George's Medical University, Lucknow 226 003, India.
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Yoshida K, Jayyosi C, Lee N, Mahendroo M, Myers KM. Mechanics of cervical remodelling: insights from rodent models of pregnancy. Interface Focus 2019; 9:20190026. [PMID: 31485313 PMCID: PMC6710664 DOI: 10.1098/rsfs.2019.0026] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2019] [Indexed: 01/01/2023] Open
Abstract
The uterine cervix undergoes a complex remodelling process during pregnancy, characterized by dramatic changes in both extracellular matrix (ECM) structure and mechanical properties. Understanding the cervical remodelling process in a term or preterm birth will aid efforts for the prevention of preterm births (PTBs), which currently affect 14.8 million babies annually worldwide. Animal models of pregnancy, particularly rodents, continue to provide valuable insights into the cervical remodelling process, through the study of changes in ECM structure and mechanical properties at defined gestation time points. Currently, there is a lack of a collective, quantitative framework to relate the complex, nonlinear mechanical behaviour of the rodent cervix to changes in ECM structure. This review aims to fill this gap in knowledge by outlining the current understanding of cervical remodelling during pregnancy in rodent models in the context of solid biomechanics. Here we highlight the collective contribution of multiple mechanical studies which give evidence that cervical softening coincides with known ECM changes throughout pregnancy. Taken together, mechanical tests on tissue from pregnant rodents reveal the cervix's remarkable ability to soften dramatically during gestation to allow for a compliant tissue that can withstand damage and can dissipate mechanical loads.
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Affiliation(s)
- Kyoko Yoshida
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Charles Jayyosi
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Nicole Lee
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Mala Mahendroo
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kristin M. Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
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9
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Conway CK, Qureshi HJ, Morris VL, Danso EK, Desrosiers L, Knoepp LR, Goergen CJ, Miller KS. Biaxial biomechanical properties of the nonpregnant murine cervix and uterus. J Biomech 2019; 94:39-48. [PMID: 31353018 DOI: 10.1016/j.jbiomech.2019.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/12/2019] [Accepted: 07/09/2019] [Indexed: 12/18/2022]
Abstract
From a biomechanical perspective, female reproductive health is an understudied area of research. There is an incomplete understanding of the complex function and interaction between the cervix and uterus. This, in part, is due to the limited research into multiaxial biomechanical functions and geometry of these organs. Knowledge of the biomechanical function and interaction between these organs may elucidate etiologies of conditions such as preterm birth. Therefore, the objective of this study was to quantify the multiaxial biomechanical properties of the murine cervix and uterus using a biaxial testing set-up. To accomplish this, an inflation-extension testing protocol (n = 15) was leveraged to quantify biaxial biomechanical properties while preserving native matrix interactions and geometry. Ultrasound imaging and histology (n = 10) were performed to evaluate regional geometry and microstructure, respectively. Histological analysis identified a statistically significant greater collagen content and significantly smaller smooth muscle content in the cervix as compared to the uterus. No statistically significant differences in elastic fibers were identified. Analysis of bilinear fits revealed a significantly stiffer response from the circumferentially orientated ECM fibers compared to axially orientated fibers in both organs. Bilinear fits and a two-fiber family constitutive model showed that the cervix was significantly less distensible than the uterus. We submit that the regional biaxial information reported in this study aids in establishing an appropriate reference configuration for mathematical models of the uterine-cervical complex. Thus, may aid future work to elucidate the biomechanical mechanisms leading to cervical or uterine conditions.
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Affiliation(s)
- Cassandra K Conway
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA.
| | - Hamna J Qureshi
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, IN 47907, USA.
| | - Victoria L Morris
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA.
| | - Elvis K Danso
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA.
| | - Laurephile Desrosiers
- Department of Female Pelvic Medicine & Reconstructive Surgery, Ochsner Clinical School, 1514 Jefferson Highway, New Orleans, LA 70121, USA.
| | - Leise R Knoepp
- Department of Female Pelvic Medicine & Reconstructive Surgery, Ochsner Clinical School, 1514 Jefferson Highway, New Orleans, LA 70121, USA.
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, IN 47907, USA.
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA.
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Jayyosi C, Lee N, Willcockson A, Nallasamy S, Mahendroo M, Myers K. The mechanical response of the mouse cervix to tensile cyclic loading in term and preterm pregnancy. Acta Biomater 2018; 78:308-319. [PMID: 30059802 PMCID: PMC6336396 DOI: 10.1016/j.actbio.2018.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/21/2018] [Accepted: 07/10/2018] [Indexed: 02/03/2023]
Abstract
A well-timed modification of both the collagen and elastic fiber network in the cervix during pregnancy accompanies the evolution of tissue mechanical parameters that are key to a successful pregnancy. Understanding of the cervical mechanical behaviour along normal and abnormal pregnancy is crucial to define the molecular events that regulate remodeling in term and preterm birth (PTB). In this study, we measured the mechanical response of mouse cervical tissue to a history of cyclic loading and quantified the tissue's ability to recover from small and large deformations. Assessments were made in nonpregnant, pregnant (gestation days 6, 12, 15 and 18) and mouse models of infection mediated PTB treated with lipopolysaccharide on gestation d15 (LPS treated) and hormone withdrawal mediated PTB on gestation d15 (RU486 treated). The current study uncovers the contributions of collagen and elastic fiber networks to the progressive change in mechanical function of the cervix through pregnancy. Premature cervical remodeling induced on gestation day 15 in the LPS infection model is characterized by distinct mechanical properties that are similar but not identical to mechanical properties at term ripening on day 18. Remodeling in the LPS infection model results in a weaker cervix, unable to withstand high loads. In contrast, the RU486 preterm model resembles the cyclic mechanical behaviour seen for term d18 cervix, where the extremely compliant tissue is able to withstand multiple cycles under large deformations without breaking. The distinct material responses to load-unload cycles in the two PTB models matches the differing microstructural changes in collagen and elastic fibers in these two models of preterm birth. Improved understanding of the impact of microstructural changes to mechanical performance of the cervix will provide insights to aid in the development of therapies for prevention of preterm birth. STATEMENT OF SIGNIFICANCE Preterm Birth (PTB) still represents a serious challenge to be overcome, considering its implications on infant mortality and lifelong health consequences. While the causes and etiologies of PTB are diverse and yet to be fully elucidated, a common pathway leading to a preterm delivery is premature cervical remodeling. Throughout pregnancy, the cervix remodels through changes of its microstructure, thus altering its mechanical properties. An appropriate timing for these transformations is critical for a healthy pregnancy and avoidance of PTB. Hence, this study aims at understanding how the mechanical function of the cervix evolves during a normal and preterm pregnancy. By performing cyclic mechanical testing on cervix samples from animal models, we assess the cervix's ability to recover from moderate and severe loading. The developed methodology links mechanical parameters to specific microstructural components. This work identifies a distinct biomechanical signature associated with inflammation mediated PTB that differs from PTB induced by hormone withdrawal and from normal term remodeling.
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Affiliation(s)
- C Jayyosi
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - N Lee
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - A Willcockson
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - S Nallasamy
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - M Mahendroo
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - K Myers
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
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Topol H, Gou K, Demirkoparan H, Pence TJ. Hyperelastic modeling of the combined effects of tissue swelling and deformation-related collagen renewal in fibrous soft tissue. Biomech Model Mechanobiol 2018; 17:1543-1567. [DOI: 10.1007/s10237-018-1043-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 06/12/2018] [Indexed: 12/01/2022]
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12
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Bürgi J, Kunz B, Abrami L, Deuquet J, Piersigilli A, Scholl-Bürgi S, Lausch E, Unger S, Superti-Furga A, Bonaldo P, van der Goot FG. CMG2/ANTXR2 regulates extracellular collagen VI which accumulates in hyaline fibromatosis syndrome. Nat Commun 2017; 8:15861. [PMID: 28604699 PMCID: PMC5472780 DOI: 10.1038/ncomms15861] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 05/09/2017] [Indexed: 01/03/2023] Open
Abstract
Loss-of-function mutations in capillary morphogenesis gene 2 (CMG2/ANTXR2), a transmembrane surface protein, cause hyaline fibromatosis syndrome (HFS), a severe genetic disorder that is characterized by large subcutaneous nodules, gingival hypertrophy and severe painful joint contracture. Here we show that CMG2 is an important regulator of collagen VI homoeostasis. CMG2 loss of function promotes accumulation of collagen VI in patients, leading in particular to nodule formation. Similarly, collagen VI accumulates massively in uteri of Antxr2-/- mice, which do not display changes in collagen gene expression, and leads to progressive fibrosis and sterility. Crossing Antxr2-/- with Col6a1-/- mice leads to restoration of uterine structure and reversion of female infertility. We also demonstrate that CMG2 may act as a signalling receptor for collagen VI and mediates its intracellular degradation.
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Affiliation(s)
- Jérôme Bürgi
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Béatrice Kunz
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Laurence Abrami
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Julie Deuquet
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Alessandra Piersigilli
- Comparative Mouse Physiology Platform, Faculty of Life Sciences, EPFL, Lausanne 1015, Switzerland
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, Bern 3012, Switzerland
| | - Sabine Scholl-Bürgi
- Medical University of Innsbruck, Clinic for Pediatrics I, Inherited Metabolic Disorders, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Ekkehart Lausch
- Department of Pediatrics, University of Freiburg, Freiburg 79106, Germany
| | - Sheila Unger
- Division of Molecular Pediatrics, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne 1011, Switzerland
| | - Andrea Superti-Furga
- Division of Molecular Pediatrics, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne 1011, Switzerland
| | - Paolo Bonaldo
- Department of Molecular Medicine, University of Padova, Padova 35122, Italy
| | - F. Gisou van der Goot
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
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Dhital B, Gul-E-Noor F, Downing KT, Hirsch S, Boutis GS. Pregnancy-Induced Dynamical and Structural Changes of Reproductive Tract Collagen. Biophys J 2017; 111:57-68. [PMID: 27410734 DOI: 10.1016/j.bpj.2016.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/27/2016] [Accepted: 05/27/2016] [Indexed: 11/16/2022] Open
Abstract
The tissues and organs of the female reproductive tract and pelvic floor undergo significant remodeling and alterations to allow for fetal growth and birth. In this work, we report on a study of the alterations of murine reproductive tract collagen resulting from pregnancy and parturition by spectrophotometry, histology, and (13)C, (2)H nuclear magnetic resonance (NMR). Four different cohorts of rats were investigated that included virgin, multiparous, two- and fourteen-day postpartum primiparous rats. (13)C CPMAS NMR revealed small chemical shift differences across the cohorts. The measured H-C internuclear correlation times indicated differences in dynamics of some motifs. However, the dynamics of the major amino acids, e.g., Gly, remained unaltered with respect to parity. (2)H NMR relaxation measurements revealed an additional water reservoir in the postpartum and multiparous cohorts pointing to redistribution of water due to pregnancy and/or parturition. Spectrophotometric measurements indicated that the collagen content in virgin rats was highest. Histological analysis of the upper vaginal wall indicated a signature of collagen fiber dissociation with smooth muscle and a change in the density of collagen fibers in multiparous rats.
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Affiliation(s)
- Basant Dhital
- Department of Physics, The Graduate Center, The City University of New York, New York, New York
| | - Farhana Gul-E-Noor
- Department of Physics, Brooklyn College, The City University of New York, Brooklyn, New York
| | - Keith T Downing
- Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York
| | - Shari Hirsch
- Department of Physics, Brooklyn College, The City University of New York, Brooklyn, New York
| | - Gregory S Boutis
- Department of Physics, The Graduate Center, The City University of New York, New York, New York; Department of Physics, Brooklyn College, The City University of New York, Brooklyn, New York.
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Myers KM, Elad D. Biomechanics of the human uterus. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28498625 DOI: 10.1002/wsbm.1388] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/23/2017] [Accepted: 03/01/2017] [Indexed: 12/15/2022]
Abstract
The appropriate biomechanical function of the uterus is required for the execution of human reproduction. These functions range from aiding the transport of the embryo to the implantation site, to remodeling its tissue walls to host the placenta, to protecting the fetus during gestation, to contracting forcefully for a safe parturition and postpartum, to remodeling back to its nonpregnant condition to renew the cycle of menstruation. To serve these remarkably diverse functions, the uterus is optimally geared with evolving and contractile muscle and tissue layers that are cued by chemical, hormonal, electrical, and mechanical signals. The relationship between these highly active biological signaling mechanisms and uterine biomechanical function is not completely understood for normal reproductive processes and pathological conditions such as adenomyosis, endometriosis, infertility and preterm labor. Animal studies have illuminated the rich structural function of the uterus, particularly in pregnancy. In humans, medical imaging techniques in ultrasound and magnetic resonance have been combined with computational engineering techniques to characterize the uterus in vivo, and advanced experimental techniques have explored uterine function using ex vivo tissue samples. The collective evidence presented in this review gives an overall perspective on uterine biomechanics related to both its nonpregnant and pregnant function, highlighting open research topics in the field. Additionally, uterine disease and infertility are discussed in the context of tissue injury and repair processes and the role of computational modeling in uncovering etiologies of disease. WIREs Syst Biol Med 2017, 9:e1388. doi: 10.1002/wsbm.1388 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - David Elad
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel.,Department of Biomedical Engineering, Columbia University, New York, NY, USA
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Yellon SM. Contributions to the dynamics of cervix remodeling prior to term and preterm birth. Biol Reprod 2017; 96:13-23. [PMID: 28395330 PMCID: PMC5803764 DOI: 10.1095/biolreprod.116.142844] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 11/01/2016] [Accepted: 11/28/2016] [Indexed: 01/05/2023] Open
Abstract
Major clinical challenges for obstetricians and neonatologists result from early cervix remodeling and preterm birth. Complications related to cervix remodeling or delivery account for significant morbidity in newborns and peripartum mothers. Understanding morphology and structure of the cervix in pregnant women is limited mostly to the period soon before and after birth. However, evidence in rodent models supports a working hypothesis that a convergence of factors promotes a physiological inflammatory process that degrades the extracellular collagen matrix and enhances biomechanical distensibility of the cervix well before the uterus develops the contractile capabilities for labor. Contributing factors to this remodeling process include innervation, mechanical stretch, hypoxia, and proinflammatory mediators. Importantly, the softening and shift to ripening occurs while progesterone is near peak concentrations in circulation across species. Since progesterone is required to maintain pregnancy, the premise of this review is that loss of responsiveness to progesterone constitutes a common final mechanism for remodeling the mammalian cervix in preparation for birth at term. Various inputs are suggested to promote signaling between stromal cells and resident macrophages to drive proinflammatory processes that advance the soft cervix into ripening. With infection, pathophysiological processes may prematurely drive components of this remodeling mechanism and lead to preterm birth. Identification of critical molecules and pathways from studies in various rodent models hold promise for novel endpoints to assess risk and provide innovative approaches to treat preterm birth or promote the progress of ripening at term.
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Affiliation(s)
- Steven M. Yellon
- Longo Center for Perinatal Biology, Departments of Basic Sciences Division of Physiology and Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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16
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Kirby MA, Heuerman AC, Custer M, Dobyns AE, Strilaeff R, Stutz KN, Cooperrider J, Elsissy JG, Yellon SM. Progesterone Receptor-Mediated Actions Regulate Remodeling of the Cervix in Preparation for Preterm Parturition. Reprod Sci 2016; 23:1473-1483. [PMID: 27233754 DOI: 10.1177/1933719116650756] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study determined whether a progesterone (P) receptor (PR)-mediated mechanism regulates morphological characteristics associated with prepartum cervix remodeling at term and with preterm birth. With focus on the transition from a soft to ripe cervix, the cervix stroma of untreated controls had reduced cell nuclei density/area and less organized extracellular collagen, while the density of macrophages/area, but not neutrophils, increased just 2 days before birth (day 17 vs day 15 or 16.5 postbreeding). Preterm birth was induced within 24 hours of treatment on day 16 postbreeding with PR antagonist or ovariectomy (Ovx). Pure or mixed PR antagonists increased the density of macrophages in the cervix within 8 hours (day 16.5 postbreeding), in advance of preterm birth. However, neither PR antagonists nor P withdrawal after Ovx affected the densities of cell nuclei and neutrophils or extracellular collagen compared to the same day controls-an indication that the cervix was sufficiently remodeled for birth to occur. To block the effect of systemic P withdrawal, Ovx pregnant mice were given a PR agonist, either pure or mixed. These treatments forestalled preterm birth and prevented further morphological remodeling of the cervix. The resulting increase in macrophage density in cervix stroma following Ovx was only blocked by a pure PR agonist. These findings support the hypothesis that inflammatory processes in the prepartum cervix that include residency of macrophages, cellular hypertrophy, and extracellular collagen structure are regulated by genomic actions of PR in a final common mechanism both at term and with induced preterm birth.
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Affiliation(s)
- Michael A Kirby
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA Departments of Pathology and Human anatomy, and Pediatrics, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Anne C Heuerman
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Melisa Custer
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Abigail E Dobyns
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Ryan Strilaeff
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Kathleen N Stutz
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Jaclyn Cooperrider
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Joseph G Elsissy
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Steven M Yellon
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA Departments of Pathology and Human anatomy, and Pediatrics, School of Medicine, Loma Linda University, Loma Linda, CA, USA Division of Physiology, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA
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Yoshida K, Mahendroo M, Vink J, Wapner R, Myers K. Material properties of mouse cervical tissue in normal gestation. Acta Biomater 2016; 36:195-209. [PMID: 26961804 DOI: 10.1016/j.actbio.2016.03.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 02/09/2016] [Accepted: 03/01/2016] [Indexed: 01/04/2023]
Abstract
UNLABELLED An appropriately timed cervical remodeling process is critical for a healthy delivery, yet little is known about the material property changes of the cervix in pregnancy because obtaining human tissue samples is difficult. Rodent models offer advantages including accurately timed pregnant tissues and genetically altered models. Determining the material properties of the mouse cervix, however, is challenging because of its small size and complex geometry. The aim of this study is to quantify cervical material property changes in a normal mouse pregnancy using a microstructurally-inspired porous fiber composite model. We mechanically test intact, whole, gestation-timed mouse cervix by pulling apart tensioned sutures through its inner canal. To interpret our mechanical testing results, we conduct an inverse finite element analysis, taking into account the combined loading state of the thick-walled cylindrical tissue. We fit the material model to previous osmotic swelling data and load-deformation data from this study using a nonlinear optimization scheme, and validate the model by predicting a separate set of deformation data. Overall, the proposed porous fiber composite model captures the mechanical behavior of the mouse cervix in large deformation. The evolution of cervical material parameters indicates that in a normal mouse pregnancy, the cervix begins to soften between day 6 and day 12 of a 19-day gestation period. The material parameter associated with the collagen fiber stiffness decreases from 3.4MPa at gestation day 6 to 9.7e-4MPa at gestation day 18, while the ground substance stiffness decreases from 2.6e-1MPa to 7.0e-4MPa. STATEMENT OF SIGNIFICANCE Accelerated cervical remodeling can lead to extremely premature births. Little is known, however, about the material property changes of the cervix in pregnancy because pregnant human tissue samples are limited. Rodent models overcome this limitation and provide access to gestation-timed samples. Measuring the material property changes of the mouse cervix in pregnancy is challenging due to its small size and complex geometry. Here, we establish a combined experimental and modeling framework. We use this framework to determine the cervical material property changes throughout a normal mouse pregnancy. We present our experimental methods for mechanically testing whole, intact cervical tissue samples. We fit a porous fiber composite material model to the mechanical data and show that the mouse cervix begins to soften between day 6 and day 12 of a 19-day gestation period.
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Gyoneva L, Hovell CB, Pewowaruk RJ, Dorfman KD, Segal Y, Barocas VH. Cell-matrix interaction during strain-dependent remodelling of simulated collagen networks. Interface Focus 2016; 6:20150069. [PMID: 26855754 DOI: 10.1098/rsfs.2015.0069] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The importance of tissue remodelling is widely accepted, but the mechanism by which the remodelling process occurs remains poorly understood. At the tissue scale, the concept of tensional homeostasis, in which there exists a target stress for a cell and remodelling functions to move the cell stress towards that target, is an important foundation for much theoretical work. We present here a theoretical model of a cell in parallel with a network to study what factors of the remodelling process help the cell move towards mechanical stability. The cell-network system was deformed and kept at constant stress. Remodelling was modelled by simulating strain-dependent degradation of collagen fibres and four different cases of collagen addition. The model did not lead to complete tensional homeostasis in the range of conditions studied, but it showed how different expressions for deposition and removal of collagen in a fibre network can interact to modulate the cell's ability to shield itself from an imposed stress by remodelling the surroundings. This study also showed how delicate the balance between deposition and removal rates is and how sensitive the remodelling process is to small changes in the remodelling rules.
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Affiliation(s)
- Lazarina Gyoneva
- Department of Biomedical Engineering , University of Minnesota , 7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455 , USA
| | - Carley B Hovell
- Department of Biomedical Engineering , University of Minnesota , 7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455 , USA
| | - Ryan J Pewowaruk
- Department of Biomedical Engineering , University of Minnesota , 7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455 , USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science , University of Minnesota , 151 Amundson Hall, 421 Washington Ave SE, Minneapolis, MN 55455 , USA
| | - Yoav Segal
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Minnesota, 717 Delaware Street SE, Suite 353, Minneapolis, MN 55414, USA; Minneapolis VA Health Care System, One Veterans Drive, Minneapolis, MN 55417, USA
| | - Victor H Barocas
- Department of Biomedical Engineering , University of Minnesota , 7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455 , USA
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Myers KM, Feltovich H, Mazza E, Vink J, Bajka M, Wapner RJ, Hall TJ, House M. The mechanical role of the cervix in pregnancy. J Biomech 2015; 48:1511-23. [PMID: 25841293 PMCID: PMC4459908 DOI: 10.1016/j.jbiomech.2015.02.065] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 02/28/2015] [Indexed: 01/10/2023]
Abstract
Appropriate mechanical function of the uterine cervix is critical for maintaining a pregnancy to term so that the fetus can develop fully. At the end of pregnancy, however, the cervix must allow delivery, which requires it to markedly soften, shorten and dilate. There are multiple pathways to spontaneous preterm birth, the leading global cause of death in children less than 5 years old, but all culminate in premature cervical change, because that is the last step in the final common pathway to delivery. The mechanisms underlying premature cervical change in pregnancy are poorly understood, and therefore current clinical protocols to assess preterm birth risk are limited to surrogate markers of mechanical function, such as sonographically measured cervical length. This is what motivates us to study the cervix, for which we propose investigating clinical cervical function in parallel with a quantitative engineering evaluation of its structural function. We aspire to develop a common translational language, as well as generate a rigorous integrated clinical-engineering framework for assessing cervical mechanical function at the cellular to organ level. In this review, we embark on that challenge by describing the current landscape of clinical, biochemical, and engineering concepts associated with the mechanical function of the cervix during pregnancy. Our goal is to use this common platform to inspire novel approaches to delineate normal and abnormal cervical function in pregnancy.
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Affiliation(s)
- Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, USA.
| | - Helen Feltovich
- Department of Obstetrics and Gynecology, Intermountain Healthcare, Provo, UT, USA; Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, & EMPA Dübendorf, Switzerland
| | - Joy Vink
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY USA
| | - Michael Bajka
- Department of Obstetrics and Gynecology, University Hospital of Zurich, Switzerland
| | - Ronald J Wapner
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY USA
| | - Timothy J Hall
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Michael House
- Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA, USA
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Gan Y, Yao W, Myers KM, Vink JY, Wapner RJ, Hendon CP. Analyzing three-dimensional ultrastructure of human cervical tissue using optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2015; 6:1090-108. [PMID: 25908997 PMCID: PMC4399652 DOI: 10.1364/boe.6.001090] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 05/20/2023]
Abstract
During pregnancy, the uterine cervix is the mechanical barrier that prevents delivery of a fetus. The underlying cervical collagen ultrastructure, which influences the overall mechanical properties of the cervix, plays a role in maintaining a successful pregnancy until term. Yet, not much is known about this collagen ultrastructure in pregnant and nonpregnant human tissue. We used optical coherence tomography to investigate the directionality and dispersion of collagen fiber bundles in the human cervix. An image analysis tool has been developed, combining a stitching method with a fiber orientation measurement, to study axially sliced cervix samples. This tool was used to analyze the ultrastructure of ex-vivo pregnant and non-pregnant hysterectomy tissue samples taken at the internal os, which is the region of the cervix adjacent to the uterus. With this tool, directionality maps of collagen fiber bundles and dispersion of collagen fiber orientation were analyzed. It was found that that the overall preferred directionality of the collagen fibers for both the nonpregnant and pregnant samples were circling around the inner cervical canal. Pregnant samples showed greater dispersion than non-pregnant samples. Lastly, we observed regional differences in collagen fiber dispersion. Fibers closer to the inner canal showed more dispersion than the fibers on the radial edges.
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Affiliation(s)
- Yu Gan
- Department of Electrical Engineering, Columbia University, New York, New York,
USA
| | - Wang Yao
- Department of Mechanical Engineering, Columbia University, New York, New York,
USA
| | - Kristin. M Myers
- Department of Mechanical Engineering, Columbia University, New York, New York,
USA
| | - Joy Y. Vink
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, New York,
USA
| | - Ronald. J. Wapner
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, New York,
USA
| | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, New York, New York,
USA
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Zork NM, Myers KM, Yoshida K, Cremers S, Jiang H, Ananth CV, Wapner RJ, Kitajewski J, Vink J. A systematic evaluation of collagen cross-links in the human cervix. Am J Obstet Gynecol 2015; 212:321.e1-8. [PMID: 25281365 DOI: 10.1016/j.ajog.2014.09.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/02/2014] [Accepted: 09/29/2014] [Indexed: 01/22/2023]
Abstract
OBJECTIVE The mechanical strength of the cervix relies on the cross-linking of the tissue's collagen network. Clinically, the internal os is functionally distinct from the external os. We sought to detect specific collagen cross-links in human cervical tissue and determine whether cross-link profiles were similar at the internal and external os. STUDY DESIGN Transverse slices of cervical tissue were obtained at the internal and external os from 13 nonpregnant, premenopausal women undergoing a benign hysterectomy. To understand how cross-links were distributed throughout the entire cervix and at the internal and external os, biopsies were obtained from 3 circumferential zones in 4 quadrants from each slice. Biopsies were pulverized, lyophilized, reduced with sodium borohydride, hydrolyzed with hydrochloric acid, and reconstituted in heptafluorobutyric acid buffer. Hydroxyproline was measured by ultraperformance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS), converted to total collagen, and normalized by dry weight. Collagen cross-links pyridinoline (PYD), deoxypyridinoline (DPD), dihydroxylysinonorleucine (DHLNL), and the nonenzymatic advanced glycation end product pentosidine (PEN) were measured by UPLC-ESI-MS/MS and reported as cross-link density ratio (cross-link/total collagen). Generalized estimated equation analysis was used to compare results between the internal and external os and to compare quadrants and zones within slices from the internal and external os to determine if cross-link profiles were similar. RESULTS A total of 592 samples from 13 patients were analyzed. Collagen cross-links are detectable in the human cervix by UPLC-ESI-MS/MS. When comparing all samples from the internal and external os, similar levels of collagen content, PYD, DHLNL, and DPD were found, but PEN density was higher at the external os (0.005 vs 0.004, P = .001). When comparing all internal os samples, significant heterogeneity was found in collagen content and cross-link densities across zones and quadrants. The external os exhibited heterogeneity only across zones. CONCLUSION Collagen cross-links (PYD, DPD, DHLNL, and PEN) are detectable by UPLC-ESI-MS/MS in the human cervix. The internal os exhibits significant collagen cross-link heterogeneity compared with the external os. Further studies are needed to evaluate how collagen cross-link heterogeneity correlates to the mechanical strength and function of the human cervix.
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Quantitative evaluation of collagen crosslinks and corresponding tensile mechanical properties in mouse cervical tissue during normal pregnancy. PLoS One 2014; 9:e112391. [PMID: 25397407 PMCID: PMC4232411 DOI: 10.1371/journal.pone.0112391] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 10/14/2014] [Indexed: 01/22/2023] Open
Abstract
The changes in the mechanical integrity of the cervix during pregnancy have implications for a successful delivery. Cervical collagens are known to remodel extensively in mice with progressing gestation leading to a soft cervix at term. During this process, mature crosslinked collagens are hypothesized to be replaced with immature less crosslinked collagens to facilitate cervical softening and ripening. To determine the mechanical role of collagen crosslinks during normal mouse cervical remodeling, tensile load-to-break tests were conducted for the following time points: nonpregnant (NP), gestation day (d) 6, 12, 15, 18 and 24 hr postpartum (PP) of the 19-day gestation period. Immature crosslinks (HLNL and DHLNL) and mature crosslinks (DPD and PYD) were measured using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). There were no significant changes in the total immature crosslink density (HLNL+DHLNL mol per collagen mol) throughout normal mouse gestation (range: 0.31-0.49). Total mature crosslink density (PYD+DPD mol per collagen mol) decreased significantly in early softening from d6 to d15 (d6: 0.17, d12: 0.097, d15: 0.026) and did not decrease with further gestation. The maturity ratio (total mature to total immature crosslinks) significantly decreased in early softening from d6 to d15 (d6: 0.2, d15: 0.074). All of the measured crosslinks correlated significantly with a measure of tissue stiffness and strength, with the exception of the immature crosslink HLNL. This data provides quantitative evidence to support the hypothesis that as mature crosslinked collagens decline, they are replaced by immature collagens to facilitate increased tissue compliance in the early softening period from d6 to d15.
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