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Villegas-Downs M, Mohammadi M, Han A, O'Brien WD, Simpson DG, Peters TA, Schlaeger JM, McFarlin BL. Trajectory of Postpartum Cervical Remodeling in Women Delivering Full-Term and Spontaneous Preterm: Sensitivity to Quantitative Ultrasound Biomarkers. ULTRASOUND IN MEDICINE & BIOLOGY 2024:S0301-5629(24)00261-8. [PMID: 39237426 DOI: 10.1016/j.ultrasmedbio.2024.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/18/2024] [Accepted: 06/27/2024] [Indexed: 09/07/2024]
Abstract
OBJECTIVE Women with a history of spontaneous preterm birth (sPTB) face an increased risk of recurrence. Yet, the factors contributing to the increased risk are unknown, hampering the development of targeted interventions. Noninvasive quantitative ultrasound (QUS) has been validated in the characterization of cervical tissue and has the potential to provide information about postpartum cervical remodeling. The objective of this study was to determine the postpartum cervical remodeling trajectories of women over 12 mo post-delivery and to determine whether there were differences between women who delivered full-term and spontaneous preterm that were sensitive to QUS biomarkers. METHODS Data were collected prospectively from 55 women: 41 who delivered full-term and 14 who delivered spontaneously preterm at 6 wk, 3, 6, 9 and 12 mo (±2 wk) postpartum. Data from QUS biomarkers: Attenuation Coefficient; Backscatter Coefficient; Shear Wave Speed; and Lizzi-Feleppa Slope, Intercept and Midband were analyzed from the acquired radiofrequency data using a Siemens S2000 ultrasound system with a transvaginal MC 9-4 MHz probe. The biomarkers were analyzed using descriptive statistics and linear mixed-effects models. RESULTS QUS biomarkers, Backscatter Coefficient and Lizzi-Feleppa Intercept showed significant differences during the year after delivery between women who had a full-term birth and sPTB (p < 0.05), suggesting that there are differences in the cervical remodeling trajectories between the two groups. All QUS biomarkers demonstrated significant variations between the full-term birth and sPTB groups over time (p < 0.05), indicating ongoing cervical remodeling for both groups during the 12-mo postpartum period. CONCLUSION QUS biomarkers identified cervical microstructure differences and trajectories in the year after delivery between women who delivered full-term and spontaneous preterm.
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Affiliation(s)
- Michelle Villegas-Downs
- Department of Human Development Nursing Science, University of Illinois Chicago, Chicago, IL, USA.
| | - Mehrdad Mohammadi
- Department of Statistics, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Aiguo Han
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - William D O'Brien
- Department of Electrical and Computer Engineering, Bioacoustics Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Douglas G Simpson
- Department of Statistics, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Tara A Peters
- Department of Human Development Nursing Science, University of Illinois Chicago, Chicago, IL, USA
| | - Judith M Schlaeger
- Department of Human Development Nursing Science, University of Illinois Chicago, Chicago, IL, USA
| | - Barbara L McFarlin
- Department of Human Development Nursing Science, University of Illinois Chicago, Chicago, IL, USA
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2
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Fang S, Shi L, Vink JSY, Feltovich H, Hall TJ, Myers KM. Equilibrium Mechanical Properties of the Nonhuman Primate Cervix. J Biomech Eng 2024; 146:081001. [PMID: 38270929 PMCID: PMC10983698 DOI: 10.1115/1.4064558] [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: 11/30/2022] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 01/26/2024]
Abstract
Cervical remodeling is critical for a healthy pregnancy. Premature tissue changes can lead to preterm birth (PTB), and the absence of remodeling can lead to post-term birth, causing significant morbidity. Comprehensive characterization of cervical material properties is necessary to uncover the mechanisms behind abnormal cervical softening. Quantifying cervical material properties during gestation is challenging in humans. Thus, a nonhuman primate (NHP) model is employed for this study. In this study, cervical tissue samples were collected from Rhesus macaques before pregnancy and at three gestational time points. Indentation and tension mechanical tests were conducted, coupled with digital image correlation (DIC), constitutive material modeling, and inverse finite element analysis (IFEA) to characterize the equilibrium material response of the macaque cervix during pregnancy. Results show, as gestation progresses: (1) the cervical fiber network becomes more extensible (nonpregnant versus pregnant locking stretch: 2.03 ± 1.09 versus 2.99 ± 1.39) and less stiff (nonpregnant versus pregnant initial stiffness: 272 ± 252 kPa versus 43 ± 43 kPa); (2) the ground substance compressibility does not change much (nonpregnant versus pregnant bulk modulus: 1.37 ± 0.82 kPa versus 2.81 ± 2.81 kPa); (3) fiber network dispersion increases, moving from aligned to randomly oriented (nonpregnant versus pregnant concentration coefficient: 1.03 ± 0.46 versus 0.50 ± 0.20); and (4) the largest change in fiber stiffness and dispersion happen during the second trimester. These results, for the first time, reveal the remodeling process of a nonhuman primate cervix and its distinct regimes throughout the entire pregnancy.
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Affiliation(s)
- Shuyang Fang
- Department of Mechanical Engineering, Columbia University, New York, NY 10027
| | - Lei Shi
- Department of Mechanical Engineering, Columbia University, New York, NY 10027
| | - Joy-Sarah Y. Vink
- Department of Obstetrics and Gynecology, Columbia University, New York, NY 10027
| | - Helen Feltovich
- Department of Maternal Fetal Medicine, Intermountain Healthcare, Park City, UT 84060
| | - Timothy J. Hall
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53706
| | - Kristin M. Myers
- Department of Mechanical Engineering, Columbia University, New York, NY 10027
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3
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Scott AK, Oyen ML. Virtual pregnancies: predicting and preventing pregnancy complications with digital twins. Lancet Digit Health 2024; 6:e436-e437. [PMID: 38906606 DOI: 10.1016/s2589-7500(24)00086-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 04/18/2024] [Indexed: 06/23/2024]
Affiliation(s)
- Adrienne K Scott
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO 63130, USA; Center for Women's Health Engineering, Washington University in St Louis, St Louis, MO 63130, USA; Center for Regenerative Medicine, Washington University in St Louis, St Louis, MO 63130, USA
| | - Michelle L Oyen
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO 63130, USA; Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO 63130, USA; Center for Women's Health Engineering, Washington University in St Louis, St Louis, MO 63130, USA; Center for Regenerative Medicine, Washington University in St Louis, St Louis, MO 63130, USA.
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4
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Fidalgo DS, Jorge RMN, Parente MPL, Louwagie EM, Malanowska E, Myers KM, Oliveira DA. Pregnancy state before the onset of labor: a holistic mechanical perspective. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01853-3. [PMID: 38758337 DOI: 10.1007/s10237-024-01853-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024]
Abstract
Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.
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Affiliation(s)
- Daniel S Fidalgo
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal.
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal.
| | - Renato M Natal Jorge
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Marco P L Parente
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Erin M Louwagie
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Ewelina Malanowska
- Department of Gynaecology, Endocrinology and Gynaecologic Oncology, Pomeranian Medical University, Szczecin, Poland
| | - Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Dulce A Oliveira
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
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Xholli A, Londero AP, Scovazzi U, Cagnacci A. Elasticity of the Cervix in Relation to Uterus Position. J Clin Med 2024; 13:2572. [PMID: 38731100 PMCID: PMC11084649 DOI: 10.3390/jcm13092572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/23/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Strain elastography allows the evaluation of tissue elasticity. Background/Objectives: Tissue elasticity depends on the content and distribution of collagen fibers and is shaped by the applied tensile forces that may differ in uteri with a different angle of flexion of the corpus on the cervix. The objective was to investigate whether the angle of uterine flexion is related to cervical tissue elasticity. Methods: The anterior angle between the longitudinal axis of the uterus corpus and that of the cervix was measured in 275 non-pregnant young women by transvaginal ultrasonography and considered both as an absolute value or categorized as ≤150°, between >150° and ≤210°, and >210°. Strain elastography was used to assess tissue elasticity by placing the probe in the anterior vaginal fornix. Tissue elasticity was evaluated in the middle of the anterior cervical compartment (ACC), in the middle of the posterior cervical compartment (PCC), in the middle portion of the cervical canal (MCC), and at the internal cervical os (ICO). In a sagittal plane MCC was evaluated across the cervical canal, and ACC and PCC at a distance equal between the cervical canal and the outer anterior or posterior part of the cervix. MCC, ACC and PCC were evaluated at equal distance between the ICO and the external cervical os. Elasticity was expressed as a color score ranging from 0.1 (low elasticity) to 3 (high elasticity). Results: The angle of uterine flexion show a negative linear relation with the elasticity of the ACC (p = 0.001) and MCC (p = 0.002) and a positive relation with the elasticity of the PCC (p = 0.054). In comparison to uteri with an angle of flexion of <150°, those with an angle of flexion of >210° had lower elasticity of the ACC (p = 0.001) and MCC (p = 0.001) and higher elasticity of the PCC (p = 0.004). The ACC/PCC and PCC/MCC elasticity ratios were also significantly different (p = 0.001). Conclusions: The angle of uterine flexion is associated with changes in cervix elasticity. Retroflexion is associated with stiffer ACC and MCC and a more elastic PCC. Differences in tissue elasticity suggest structural changes of the cervix that may have implication in variate obstetric and gynecological conditions.
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Affiliation(s)
- Anjeza Xholli
- Teaching Unit of Obstetrics and Gynecology, IRCCS Ospedale San Martino of Genova, 16132 Genova, Italy; (A.X.); (U.S.)
| | - Ambrogio Pietro Londero
- Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Infant Health (DiNOGMI), University of Genova, 16132 Genoa, Italy;
| | - Umberto Scovazzi
- Teaching Unit of Obstetrics and Gynecology, IRCCS Ospedale San Martino of Genova, 16132 Genova, Italy; (A.X.); (U.S.)
- Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Infant Health (DiNOGMI), University of Genova, 16132 Genoa, Italy;
| | - Angelo Cagnacci
- Teaching Unit of Obstetrics and Gynecology, IRCCS Ospedale San Martino of Genova, 16132 Genova, Italy; (A.X.); (U.S.)
- Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Infant Health (DiNOGMI), University of Genova, 16132 Genoa, Italy;
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6
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Ahmad MA, Vergote S, Vander Poorten E, Devlieger R, De Coppi P, Mazza E, Deprest J. Exteriorization of the uterus reduces fetoscopic cannula-induced stress and strain: A finite element model analysis. Prenat Diagn 2024; 44:99-107. [PMID: 38185824 DOI: 10.1002/pd.6496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/30/2023] [Accepted: 12/02/2023] [Indexed: 01/09/2024]
Abstract
OBJECTIVE To estimate stresses and strains in the uterine wall and fetal membranes with single/multi-port fetoscopy, simulating either a percutaneous access or via exteriorized uterus. STUDY DESIGN Finite element models based on anatomical dimensions, material properties and boundary conditions were created to simulate stresses, strains and displacements on the uterine wall and fetal membranes during simulated fetal surgery either via exteriorized uterus or percutaneous approach, and with one or three cannulas. Clinically, we measured the anatomical layer thickness and cannula entry point displacement in patients undergoing single port percutaneous fetoscopy. RESULTS Simulations demonstrate that single port percutaneous fetoscopy increases stress on the fetal membranes (+105%, 128 to 262 kPa) and uterine wall (+115%, 0.89 to 1.9 kPa) compared to exteriorized uterine access. Using three ports increases stress by 110% (148 to 312 kPa) on membranes and 113% (1.08 to 2.3 kPa) on uterine wall. Finite Element Method showed 0.75 cm uterine entry point displacement from the cutaneous entry, while clinical measurements demonstrated displacement of more than double (1.69 ± 0.58 cm), suggesting modeled measurements may be underestimations. CONCLUSION The stresses and strains on the fetal membranes and uterus are double as high when entering percutaneously than via an exteriorized uterus. Based on what can be clinically measured, this may be an underestimation.
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Affiliation(s)
- Mirza A Ahmad
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
- Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Simen Vergote
- Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
- Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium
| | | | - Roland Devlieger
- Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
- Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium
| | - Paolo De Coppi
- Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
- Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium
- Institute for Child and Women's Health, University College London, London, UK
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
- Swiss Federal Laboratories for Materials Science and Technology, Empa, Dübendorf, Switzerland
| | - Jan Deprest
- Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
- Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium
- Institute for Child and Women's Health, University College London, London, UK
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7
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Monitoring uterine contractions during labor: current challenges and future directions. Am J Obstet Gynecol 2023; 228:S1192-S1208. [PMID: 37164493 DOI: 10.1016/j.ajog.2022.10.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 03/21/2023]
Abstract
Organ-level models are used to describe how cellular and tissue-level contractions coalesce into clinically observable uterine contractions. More importantly, these models provide a framework for evaluating the many different contraction patterns observed in laboring patients, ideally offering insight into the pitfalls of currently available recording modalities and suggesting new directions for improving recording and interpretation of uterine contractions. Early models proposed wave-like propagation of bioelectrical activity as the sole mechanism for recruiting the myometrium to participate in the contraction and increase contraction strength. However, as these models were tested, the results consistently revealed that sequentially propagating waves do not travel long distances and do not encompass the gravid uterus. To resolve this discrepancy, a model using 2 mechanisms, or a "dual model," for organ-level signaling has been proposed. In the dual model, the myometrium is recruited by action potentials that propagate wave-like as far as 10 cm. At longer distances, the myometrium is recruited by a mechanotransduction mechanism that is triggered by rising intrauterine pressure. In this review, we present the influential models of uterine function, highlighting their main features and inconsistencies, and detail the role of intrauterine pressure in signaling and cervical dilation. Clinical correlations demonstrate the application of organ-level models. The potential to improve the recording and clinical interpretation of uterine contractions when evaluating labor is discussed, with emphasis on uterine electromyography. Finally, 7 questions are posed to help guide future investigations on organ-level signaling mechanisms.
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Ostadi Moghaddam A, Arshee MR, Lin Z, Sivaguru M, Phillips H, McFarlin BL, Toussaint KC, Wagoner Johnson AJ. Orientation-dependent indentation reveals the crosslink-mediated deformation mechanisms of collagen fibrils. Acta Biomater 2023; 158:347-357. [PMID: 36638936 PMCID: PMC10039649 DOI: 10.1016/j.actbio.2023.01.005] [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: 09/20/2022] [Revised: 12/18/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
The spatial arrangement and interactions of the extracellular matrix (ECM) components control the mechanical behavior of tissue at multiple length scales. Changes in microscale deformation mechanisms affect tissue function and are often hallmarks of remodeling and disease. Despite their importance, the deformation mechanisms that modulate the mechanical behavior of collagenous tissue, particularly in indentation and compression modes of deformation, remain poorly understood. Here, we develop an integrated computational and experimental approach to investigate the deformation mechanisms of collagenous tissue at the microscale. While the complex deformation arising from indentation with a spherical probe is often considered a pitfall rather than an opportunity, we leverage this orientation-dependent deformation to examine the shear-regulated interactions of collagen fibrils and the role of crosslinks in modulating these interactions. We specifically examine tendon and cervix, two tissues rich in collagen with quite different microstructures and mechanical functions. We find that interacting, crosslinked collagen fibrils resist microscale longitudinal compressive forces, while widely used constitutive models fail to capture this behavior. The reorientation of collagen fibrils tunes the compressive stiffness of complex tissues like cervix. This study offers new insights into the mechanical behavior of collagen fibrils during indentation, and more generally, under longitudinal compressive forces, and illustrates the mechanisms that contribute to the experimentally observed orientation-dependent mechanical behavior. STATEMENT OF SIGNIFICANCE: Remodeling and disease can affect the deformation and interaction of tissue constituents, and thus mechanical function of tissue. Yet, the microscale deformation mechanisms are not well characterized in many tissues. Here, we develop a combined experimental-computational approach to infer the microscale deformation mechanisms of collagenous tissues with very different functions: tendon and cervix. Results show that collagen fibrils resist microscale forces along their length, though widely-used constitutive models do not account for this mechanism. This deformation process partially modulates the compressive stiffness of complex tissues such as cervix. Computational modeling shows that crosslink-mediated shear deformations are central to this unexpected behavior. This study offers new insights into the deformation mechanisms of collagenous tissue and the function of collagen crosslinkers.
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Affiliation(s)
- A Ostadi Moghaddam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - M R Arshee
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Z Lin
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - M Sivaguru
- Flow Cytometry and Microscopy to Omics, Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
| | - H Phillips
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - B L McFarlin
- Department of Women, Children and Family Health Science, University of Illinois College of Nursing, Chicago, IL 60612, USA
| | - K C Toussaint
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - A J Wagoner Johnson
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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9
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Measurement of cervical softness before cerclage placement with an aspiration-based device. Am J Obstet Gynecol MFM 2023; 5:100881. [PMID: 36724813 DOI: 10.1016/j.ajogmf.2023.100881] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023]
Abstract
BACKGROUND An abnormally soft cervix could contribute to the pathophysiology of cervical shortening and cervical insufficiency. Multiple techniques to measure cervical softness have been developed but none are used routinely in clinical practice. A clinically acceptable technique to measure cervical softness could improve identification of patients at risk for cervix-related preterm birth. OBJECTIVE This study aimed to measure cervical softness in patients with cervical insufficiency and in normal controls using a novel, aspiration-based device. We hypothesized that the cervix is softer in patients with cervical insufficiency. STUDY DESIGN This was a cross-sectional study of patients presenting for cerclage at a single academic medical center. Cervical softness was measured using a noninvasive, aspiration-based device placed on the anterior lip of the cervix during a speculum examination. The device measured the aspiration pressure required to displace cervical tissue to a predefined deformation level. Stiff tissue required increased aspiration pressure, whereas soft tissue required lower pressure values. Cerclage patients were subdivided into 3 groups, namely history-indicated, ultrasound-indicated, and examination-indicated cerclage. Controls were healthy volunteers between 12+0 weeks and 23+6 weeks of gestation without a history of cervical insufficiency and were matched by gestational age to the patients in the cerclage groups. Women with a cerclage in place, multiple gestations, active genital infection, or previous cervical excision procedures were excluded. Delivery information was subsequently recorded as well. RESULTS Data from 133 women were analyzed; of those, 54 patients were in the cerclage group (23 history-indicated, 12 ultrasound-indicated, and 19 examination-indicated participants) and 79 were controls (40 in the first trimester and 39 in the second trimester groups). Patients who presented for ultrasound-indicated cerclage had significantly softer cervices (median; interquartile range) than second trimester controls (62 mbar; 50.5-114 vs 81 mbar; 75-101; P=.042). The difference in cervical softness was not significantly different between the history-indicated and examination-indicated cerclage groups and their respective control groups. CONCLUSION Patients presenting for ultrasound-indicated cerclage had significantly softer cervices than normal controls as measured by an aspiration-based device. Quantitative measurement of cervical softness with the aspiration-based device is a promising technique for objective measurement of cervical softness during pregnancy.
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10
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Shi L, Hu L, Lee N, Fang S, Myers K. Three-Dimensional Anisotropic Hyperelastic Constitutive Model Describing the Mechanical Response of Human and Mouse Cervix. Acta Biomater 2022; 150:277-294. [PMID: 35931278 DOI: 10.1016/j.actbio.2022.07.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 07/25/2022] [Accepted: 07/28/2022] [Indexed: 11/18/2022]
Abstract
The mechanical function of the uterine cervix is critical for a healthy pregnancy. During pregnancy, the cervix undergoes significant softening to allow for a successful delivery. Abnormal cervical remodeling is suspected to contribute to preterm birth. Material constitutive models describing known biological shifts in pregnancy are essential to predict the mechanical integrity of the cervix. In this work, the material response of human cervical tissue under spherical indentation and uniaxial tensile tests loaded along different anatomical directions is experimentally measured. A deep-learning segmentation tool is applied to capture the tissue deformation during the uniaxial tensile tests. A 3-dimensional, equilibrium anisotropic continuous fiber constitutive model is formulated, considering collagen fiber directionality, fiber bundle dispersion, and the entropic nature of wavy cross-linked collagen molecules. Additionally, the universality of the material model is demonstrated by characterizing previously published mouse cervix mechanical data. Overall, the proposed material model captures the tension-compression asymmetric material responses and the remodeling characteristics of both human and mouse cervical tissue. The pregnant (PG) human cervix (mean locking stretch ζ=2.4, mean initial stiffness ξ=12 kPa, mean bulk modulus κ=0.26 kPa, mean dispersion b=1.0) is more compliant compared with the nonpregnant (NP) cervix (mean ζ=1.3, mean ξ=32 kPa, mean κ=1.4 kPa, mean b=1.4). Creating a validated material model, which describes the role of collagen fiber directionality, dispersion, and crosslinking, enables tissue-level biomechanical simulations to determine which material and anatomical factors drive the cervix to open prematurely. STATEMENT OF SIGNIFICANCE: In this study, we report a 3D anisotropic hyperelastic constitutive model based on Langevin statistic mechanics and successfully describe the material behavior of both human and mouse cervical tissue using this model. This model bridges the connection between the extracellular matrix (ECM) microstructure remodeling and the macro mechanical properties change of the cervix during pregnancy via microstructure-associated material parameters. This is the first model, to our knowledge, to connect the the entropic nature of wavy cross-linked collagen molecules with the mechanical behavior of the cervix. Inspired by microstructure, this model provides a foundation to understand further the relationship between abnormal cervical ECM remodeling and preterm birth. Furthermore, with a relatively simple form, the proposed model can be applied to other fibrous tissues in the future.
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Affiliation(s)
- Lei Shi
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Lingfeng Hu
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Nicole Lee
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Shuyang Fang
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Kristin Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
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11
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Sahin E, Madendag Y, Eraslan Sahin M, Col Madendag I, Kirlangic MM. New ultrasonographic midtrimester scoring method for predicting spontaneous preterm birth in uncomplicated asymptomatic twin pregnancies. J Perinat Med 2022; 50:567-572. [PMID: 35146974 DOI: 10.1515/jpm-2021-0419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 01/24/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The aim of the present study was to evaluate a new ultrasonographic scoring method that could predict spontaneous preterm birth (sPTB) in uncomplicated twin pregnancies during routine anomaly screening in the midtrimester. METHODS This prospective study included women with a monochorionic diamniotic (MCDA) or dichorionic diamniotic (DCDA) twin pregnancy gestational ages from 170/7 through 226/7. A new ultrasonographic score between 0 and 5 points was calculated using cervical length (CL), uterocervical angle (UCA), and cervical dilatation status during routine anomaly screening in the midtrimester. The primary outcome of the study was the prediction of sPTB < 32 and <34 gestational weeks. RESULTS A total of 118 pregnant women with twins were evaluated, 31 of whom delivered before 34 gestational weeks an 87 of whom delivered after 34 gestational weeks. The sensitivity and specificity values were separately calculated for scores of 3.5 and 2.5 for predicting sPTB < 32 gestational weeks. The cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 82%. When the score was 2.5, the sensitivity and specificity were 86 and 71%, respectively. To determine a score for predicting sPTB < 34 gestational week cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 90%. When the score value was 2.5, the sensitivity and specificity of the method were 83 and 81%, respectively. CONCLUSIONS Our results indicated that the midtrimester new scoring is a simple technique that can be easily used as an improved tool for predicting the risk of sPTB in women with a twin pregnancy.
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Affiliation(s)
- Erdem Sahin
- Department of Obstetrics and Gynecology, Erciyes University Medicine Faculty, Kayseri, Turkey
| | - Yusuf Madendag
- Department of Obstetrics and Gynecology, Erciyes University Medicine Faculty, Kayseri, Turkey
| | | | - Ilknur Col Madendag
- Department of Obstetrics and Gynecology, Kayseri City Hospital, Kayseri, Turkey
| | - Mehmet Mete Kirlangic
- Department of Obstetrics and Gynecology, Tuzla Government Hospital, Istanbul, Turkey
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12
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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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13
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Wolf HM, Romero R, Strauss JF, Hassan SS, Latendresse SJ, Webb BT, Tarca AL, Gomez-Lopez N, Hsu CD, York TP. Study protocol to quantify the genetic architecture of sonographic cervical length and its relationship to spontaneous preterm birth. BMJ Open 2022; 12:e053631. [PMID: 35301205 PMCID: PMC8932269 DOI: 10.1136/bmjopen-2021-053631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION A short cervix (cervical length <25 mm) in the midtrimester (18-24 weeks) of pregnancy is a powerful predictor of spontaneous preterm delivery. Although the biological mechanisms of cervical change during pregnancy have been the subject of extensive investigation, little is known about whether genes influence the length of the cervix, or the extent to which genetic factors contribute to premature cervical shortening. Defining the genetic architecture of cervical length is foundational to understanding the aetiology of a short cervix and its contribution to an increased risk of spontaneous preterm delivery. METHODS/ANALYSIS The proposed study is designed to characterise the genetic architecture of cervical length and its genetic relationship to gestational age at delivery in a large cohort of Black/African American women, who are at an increased risk of developing a short cervix and delivering preterm. Repeated measurements of cervical length will be modelled as a longitudinal growth curve, with parameters estimating the initial length of the cervix at the beginning of pregnancy, and its rate of change over time. Genome-wide complex trait analysis methods will be used to estimate the heritability of cervical length growth parameters and their bivariate genetic correlation with gestational age at delivery. Polygenic risk profiling will assess maternal genetic risk for developing a short cervix and subsequently delivering preterm and evaluate the role of cervical length in mediating the relationship between maternal genetic variation and gestational age at delivery. ETHICS/DISSEMINATION The proposed analyses will be conducted using deidentified data from participants in an IRB-approved study of longitudinal cervical length who provided blood samples and written informed consent for their use in future genetic research. These analyses are preregistered with the Center for Open Science using the AsPredicted format and the results and genomic summary statistics will be published in a peer-reviewed journal.
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Affiliation(s)
- Hope M Wolf
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
- Department of Human and Molecular Genetics, Virginia Institute for Psychiatric and Behavioral Genetics, Richmond, Virginia, USA
| | - Roberto Romero
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, U.S. Department of Health and Human Services, Detroit, Michigan, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, USA
- Detroit Medical Center, Detroit, Michigan, USA
| | - Jerome F Strauss
- Department of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
- Department of Obstetrics and Gynecology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Sonia S Hassan
- Office of Women's Health, Wayne State University, Detroit, Michigan, USA
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Shawn J Latendresse
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Bradley T Webb
- GenOmics, Bioinformatics, and Translational Research Center, Biostatistics and Epidemiology Division, RTI International, Research Triangle Park, North Carolina, USA
- Department of Psychiatry, Virginia Institute for Psychiatric and Behavioral Genetics, Richmond, Virginia, USA
| | - Adi L Tarca
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, U.S. Department of Health and Human Services, Detroit, Michigan, USA
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Department of Computer Science, Wayne State University College of Engineering, Detroit, Michigan, USA
| | - Nardhy Gomez-Lopez
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, U.S. Department of Health and Human Services, Detroit, Michigan, USA
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Chaur-Dong Hsu
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, U.S. Department of Health and Human Services, Detroit, Michigan, USA
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Timothy P York
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
- Department of Human and Molecular Genetics, Virginia Institute for Psychiatric and Behavioral Genetics, Richmond, Virginia, USA
- Department of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
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14
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Moghaddam AO, Lin Z, Sivaguru M, Phillips H, McFarlin BL, Toussaint KC, Johnson AJW. Heterogeneous microstructural changes of the cervix influence cervical funneling. Acta Biomater 2022; 140:434-445. [PMID: 34958969 PMCID: PMC8828692 DOI: 10.1016/j.actbio.2021.12.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/03/2021] [Accepted: 12/21/2021] [Indexed: 12/31/2022]
Abstract
The cervix acts as a dynamic barrier between the uterus and vagina, retaining the fetus during pregnancy and allowing birth at term. Critical to this function, the physical properties of the cervix change, or remodel, but abnormal remodeling can lead to preterm birth (PTB). Although cervical remodeling has been studied, the complex 3D cervical microstructure has not been well-characterized. In this complex, dynamic, and heterogeneous tissue microenvironment, the microstructural changes are likely also heterogeneous. Using quantitative, 3D, second-harmonic generation microscopy, we demonstrate that rat cervical remodeling during pregnancy is not uniform across the cervix; the collagen fibers orient progressively more perpendicular to the cervical canals in the inner cervical zone, but do not reorient in other regions. Furthermore, regions that are microstructurally distinct early in pregnancy become more similar as pregnancy progresses. We use a finite element simulation to show that heterogeneous regional changes influence cervical funneling, an important marker of increased risk for PTB; the internal cervical os shows ∼6.5x larger radial displacement when fibers in the inner cervical zone are parallel to the cervical canals compared to when fibers are perpendicular to the canals. Our results provide new insights into the microstructural and tissue-level cervical changes that have been correlated with PTB and motivate further clinical studies exploring the origins of cervical funneling. STATEMENT OF SIGNIFICANCE: Cervical funneling, or dilation of the internal cervical os, is highly associated with increased risk of preterm birth. This study explores the 3D microstructural changes of the rat cervix during pregnancy and illustrates how these changes influence cervical funneling, assuming similar evolution in rats and humans. Quantitative imaging showed that microstructural remodeling during pregnancy is nonuniform across cervical regions and that initially distinct regions become more similar. We report, for the first time, that remodeling of the inner cervical zone can influence the dilation of the internal cervical os and allow the cervix to stay closed despite increased intrauterine pressure. Our results suggest a possible relationship between the microstructural changes of this zone and cervical funneling, motivating further clinical investigations.
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Affiliation(s)
- A. Ostadi Moghaddam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
| | - Z. Lin
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - M. Sivaguru
- Flow Cytometry and Microscopy to Omics, Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
| | - H. Phillips
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - B. L. McFarlin
- Department of Women, Children and Family Health Science, University of Illinois College of Nursing, Chicago, IL 60612, USA
| | - K. C. Toussaint
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - A. J. Wagoner Johnson
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA,Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA,Corresponding author at: 2101A Mechanical Engineering Laboratory MC-244, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, United States.
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15
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Tissue Engineering for Cervical Function in Pregnancy. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2022; 22. [DOI: 10.1016/j.cobme.2022.100385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Clark-Patterson G, Domingo M, Miller KS. Biomechanics of Pregnancy and Vaginal Delivery. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2022. [DOI: 10.1016/j.cobme.2022.100386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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17
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Gou K, Baek S, Lutnesky MMF, Han HC. Growth-profile configuration for specific deformations of tubular organs: A study of growth-induced thinning and dilation of the human cervix. PLoS One 2021; 16:e0255895. [PMID: 34379659 PMCID: PMC8357173 DOI: 10.1371/journal.pone.0255895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 07/26/2021] [Indexed: 12/02/2022] Open
Abstract
Growth is a significant factor that results in deformations of tubular organs, and particular deformations associated with growth enable tubular organs to perform certain physiological functions. Configuring growth profiles that achieve particular deformation patterns is critical for analyzing potential pathological conditions and for developing corresponding clinical treatments for tubular organ dysfunctions. However, deformation-targeted growth is rarely studied. In this article, the human cervix during pregnancy is studied as an example to show how cervical thinning and dilation are generated by growth. An advanced hyperelasticity theory called morphoelasticity is employed to model the deformations, and a growth tensor is used to represent growth in three principle directions. The computational results demonstrate that both negative radial growth and positive circumferential growth facilitate thinning and dilation. Modeling such mixed growth represents an advancement beyond commonly used uniform growth inside tissues to study tubular deformations. The results reveal that complex growth may occur inside tissues to achieve certain tubular deformations. Integration of further biochemical and cellular activities that initiate and mediate such complex growth remains to be explored.
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Affiliation(s)
- Kun Gou
- Department of Mathematical, Physical, and Engineering Sciences, Texas A&M University-San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| | - Seungik Baek
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, United States of America
| | - Marvin M. F. Lutnesky
- Department of Life Sciences, Texas A&M University-San Antonio, San Antonio, Texas, United States of America
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, Texas, United States of America
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18
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Liu D, Chen C, Zhang T. Image-Based Polygonal Lattices for Mechanical Modeling of Biological Materials: 2D Demonstrations. ACS Biomater Sci Eng 2021. [PMID: 34060803 DOI: 10.1021/acsbiomaterials.0c01772] [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: 11/29/2022]
Abstract
Understanding the structure-property relationship of biological materials, such as bones, teeth, cells, and biofilms, is critical for diagnosing diseases and developing bioinspired materials and structures. The intrinsic multiphase heterogeneity with interfaces places great challenges for mechanical modeling. Here, we develop an image-based polygonal lattice model for simulating the mechanical deformation of biological materials with complicated shapes and interfaces. The proposed lattice model maintains the uniform meshes inside the homogeneous phases and restricts the irregular polygonal meshes near the boundaries or interfaces. This approach significantly simplifies the mesh generation from images of biological structures with complicated geometries. The conventional finite element simulations validate this polygonal lattice model. We further demonstrate that the image-based polygonal lattices generate meshes from images of composite structures with multiple inclusions and capture the nonlinear mechanical deformation. We conclude the paper by highlighting a few future research directions that will benefit from the functionalities of polygonal lattice modeling.
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Affiliation(s)
- Di Liu
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, New York 13244, United States.,BioInspired Syracuse, Syracuse University, Syracuse, New York 13244, United States
| | - Chao Chen
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, New York 13244, United States.,BioInspired Syracuse, Syracuse University, Syracuse, New York 13244, United States
| | - Teng Zhang
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, New York 13244, United States.,BioInspired Syracuse, Syracuse University, Syracuse, New York 13244, United States
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19
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Conway CK, Varghese A, Mahendroo M, Miller KS. The Role of Biaxial Loading on Smooth Muscle Contractility in the Nulliparous Murine Cervix. Ann Biomed Eng 2021; 49:1874-1887. [PMID: 33880630 DOI: 10.1007/s10439-021-02778-z] [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: 12/11/2020] [Accepted: 04/06/2021] [Indexed: 12/17/2022]
Abstract
Throughout the estrus cycle, the extracellular matrix (ECM) and cervical smooth muscle cells (cSMC) coordinate to accomplish normal physiologic function in the non-pregnant cervix. While previous uniaxial experiments provide fundamental knowledge about cervical contractility and biomechanics, the specimen preparation is disruptive to native organ geometry and does not permit simultaneous assessment of circumferential and axial properties. Thus, a need remains to investigate cervical contractility and passive biomechanics within physiologic multiaxial loading. Biaxial inflation-extension experiments overcome these limitations by preserving geometry, ECM-cell interactions, and multiaxially loading the cervix. Utilizing in vivo pressure measurements and inflation-extension testing, this study presented methodology and examined maximum biaxial contractility and biomechanics in the nulliparous murine cervix. The study showed that increased pressure resulted in decreased contractile potential in the circumferential direction, however, axial contractility remained unaffected. Additionally, total change in axial stress ([Formula: see text]) increased significantly (p < 0.05) compared to circumferential stress ([Formula: see text]) with maximum contraction. However, passive stiffness was significantly greater (p < 0.01) in the circumferential direction. Overall, axial cSMC may have a critical function in maintaining cervical homeostasis during normal function. Potentially, a loss of axial contractility in the cervix during pregnancy may result in maladaptive remodeling such as cervical insufficiency.
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Affiliation(s)
- Cassandra K Conway
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA, 70118, USA
| | - Asha Varghese
- Obstetrics and Gynecology and Green Center for Reproductive Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Mala Mahendroo
- Obstetrics and Gynecology and Green Center for Reproductive Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Ave, New Orleans, LA, 70118, USA.
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20
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Fang S, McLean J, Shi L, Vink JSY, Hendon CP, Myers KM. Anisotropic Mechanical Properties of the Human Uterus Measured by Spherical Indentation. Ann Biomed Eng 2021; 49:1923-1942. [PMID: 33880632 DOI: 10.1007/s10439-021-02769-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/26/2021] [Indexed: 12/11/2022]
Abstract
The mechanical function of the uterus is critical for a successful pregnancy. During gestation, uterine tissue grows and stretches to many times its size to accommodate the growing fetus, and it is hypothesized the magnitude of uterine tissue stretch triggers the onset of contractions. To establish rigorous mechanical testing protocols for the human uterus in hopes of predicting tissue stretch during pregnancy, this study measures the anisotropic mechanical properties of the human uterus using optical coherence tomography (OCT), instrumented spherical indentation, and video extensometry. In this work, we perform spherical indentation and digital image correlation to obtain the tissue's force and deformation response to a ramp-hold loading regimen. We translate previously reported fiber architecture, measured via optical coherence tomography, into a constitutive fiber composite material model to describe the equilibrium material behavior during indentation. We use an inverse finite element method integrated with a genetic algorithm (GA) to fit the material model to our experimental data. We report the mechanical properties of human uterine specimens taken across different anatomical locations and layers from one non-pregnant (NP) and one pregnant (PG) patient; both patients had pathological uterine tissue. Compared to NP uterine tissue, PG tissue has a more dispersed fiber distribution and equivalent stiffness material parameters. In both PG and NP uterine tissue, the mechanical properties differ significantly between anatomical locations.
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Affiliation(s)
- Shuyang Fang
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - James McLean
- Department of Electrical Engineering, Columbia University, New York, NY, 10027, USA
| | - Lei Shi
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Joy-Sarah Y Vink
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Christine P Hendon
- Department of Electrical Engineering, Columbia University, New York, NY, 10027, USA
| | - Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
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21
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Roa C, Du Le VN, Mahendroo M, Saytashev I, Ramella-Roman JC. Auto-detection of cervical collagen and elastin in Mueller matrix polarimetry microscopic images using K-NN and semantic segmentation classification. BIOMEDICAL OPTICS EXPRESS 2021; 12:2236-2249. [PMID: 33996226 PMCID: PMC8086465 DOI: 10.1364/boe.420079] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/10/2021] [Accepted: 03/17/2021] [Indexed: 05/25/2023]
Abstract
We propose an approach for discriminating fibrillar collagen fibers from elastic fibers in the mouse cervix in Mueller matrix microscopy using convolutional neural networks (CNN) and K-nearest neighbor (K-NN) for classification. Second harmonic generation (SHG), two-photon excitation fluorescence (TPEF), and Mueller matrix polarimetry images of the mice cervix were collected with a self-validating Mueller matrix micro-mesoscope (SAMMM) system. The components and decompositions of each Mueller matrix were arranged as individual channels of information, forming one 3-D voxel per cervical slice. The classification algorithms analyzed each voxel and determined the amount of collagen and elastin, pixel by pixel, on each slice. SHG and TPEF were used as ground truths. To assess the accuracy of the results, mean-square error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity (SSIM) were used. Although the training and testing is limited to 11 and 5 cervical slices, respectively, MSE accuracy was above 85%, SNR was greater than 40 dB, and SSIM was larger than 90%.
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Affiliation(s)
- Camilo Roa
- Department of Biological Sciences, College of Arts, Sciences and Education, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
- These authors contributed equally
| | - V N Du Le
- Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, 10555 West Flagler Street, Miami, FL 33174, USA
- These authors contributed equally
| | - Mala Mahendroo
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Ilyas Saytashev
- Department of Ophthalmology, Herbert Wertheim College of Medicine, Florida International University, 11200 SW 8 Street, Miami, FL 33199, USA
| | - Jessica C Ramella-Roman
- Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, 10555 West Flagler Street, Miami, FL 33174, USA
- Department of Ophthalmology, Herbert Wertheim College of Medicine, Florida International University, 11200 SW 8 Street, Miami, FL 33199, USA
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22
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Xholli A, Simoncini G, Vujosevic S, Trombetta G, Chiodini A, Ferraro MF, Cagnacci A. Menstrual Pain and Elasticity of Uterine Cervix. J Clin Med 2021; 10:jcm10051110. [PMID: 33799937 PMCID: PMC7961784 DOI: 10.3390/jcm10051110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/25/2022] Open
Abstract
Menstrual pain is consequent to intense uterine contraction aimed to expel menstrual flow through downstream uterine cervix. Herein it was evaluated whether characteristics of uterine cervix are associated with intensity of menstrual pain. Ultrasound elastography was used to analyze cervix elasticity of 75 consecutive outpatient women. Elasticity was related to intensity of menstrual pain defined by a Visual Analogue Scale (VAS). Four regions of interest (ROI) were considered: internal uterine orifice (IUO), anterior (ACC) and posterior cervical (PCC) compartment and middle cervical canal (MCC). Tissue elasticity, evaluated by color score (from 0.5 = blue/violet (low elasticity) to 3.0 = red (high elasticity), and percent tissue deformation was analyzed. Elasticity of IUO was lower (p = 0.0001) than that of MCC or ACC, and it was negatively related (R2 = 0.428; p = 0.0001) to menstrual VAS (CR −2.17; 95%CI −3.80, −0.54; p = 0.01). Presence of adenomyosis (CR 3.24; 95% CI 1.94, 4.54; p = 0.0001) and cervix tenderness at clinical examination (CR 2.74; 95% CI 1.29, 4.20; p = 0.0004), were also independently related to menstrual VAS. At post hoc analysis, women with vs. without menstrual pain had lower IUO elasticity, expressed as color score (0.72 ± 0.40 vs. 0.92 ± 0.42; p = 0.059), lower percent tissue deformation at IUO (0.09 ± 0.05 vs. 0.13 ± 0.08; p = 0.025), a higher prevalence of cervical tenderness at bimanual examination (36.2% vs. 9.5%; p = 0.022) and a higher prevalence of adenomyosis (46.5% vs. 19.9%; p = 0.04). These preliminary data indicate that IUO elasticity is associated with the presence and the intensity of menstrual pain. Mechanisms determining IUO elasticity are useful to be explored.
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Affiliation(s)
- Anjeza Xholli
- Academic Unit of Obstetrics and Gynecology, Maternal and Child Health (DiNOGMI), IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy; (A.X.); (A.C.); (M.F.F.)
| | - Gianluca Simoncini
- Academic Unit of Obstetrics and Gynecology, Azienda Sanitaria Universitaria di Udine, 33100 Udine, Italy; (G.S.); (S.V.); (G.T.)
| | - Sonja Vujosevic
- Academic Unit of Obstetrics and Gynecology, Azienda Sanitaria Universitaria di Udine, 33100 Udine, Italy; (G.S.); (S.V.); (G.T.)
| | - Giulia Trombetta
- Academic Unit of Obstetrics and Gynecology, Azienda Sanitaria Universitaria di Udine, 33100 Udine, Italy; (G.S.); (S.V.); (G.T.)
| | - Alessandra Chiodini
- Academic Unit of Obstetrics and Gynecology, Maternal and Child Health (DiNOGMI), IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy; (A.X.); (A.C.); (M.F.F.)
| | - Mattia Francesco Ferraro
- Academic Unit of Obstetrics and Gynecology, Maternal and Child Health (DiNOGMI), IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy; (A.X.); (A.C.); (M.F.F.)
| | - Angelo Cagnacci
- Academic Unit of Obstetrics and Gynecology, Maternal and Child Health (DiNOGMI), IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy; (A.X.); (A.C.); (M.F.F.)
- Correspondence:
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Chatterjee A, Saghian R, Dorogin A, Cahill LS, Sled JG, Lye S, Shynlova O. Combination of histochemical analyses and micro-MRI reveals regional changes of the murine cervix in preparation for labor. Sci Rep 2021; 11:4903. [PMID: 33649420 PMCID: PMC7921561 DOI: 10.1038/s41598-021-84036-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/29/2021] [Indexed: 01/31/2023] Open
Abstract
The cervix is responsible for maintaining pregnancy, and its timely remodeling is essential for the proper delivery of a baby. Cervical insufficiency, or "weakness", may lead to preterm birth, which causes infant morbidities and mortalities worldwide. We used a mouse model of pregnancy and term labor, to examine the cervical structure by histology (Masson Trichome and Picrosirius Red staining), immunohistochemistry (Hyaluronic Acid Binding Protein/HABP), and ex-vivo MRI (T2-weighted and diffusion tensor imaging), focusing on two regions of the cervix (i.e., endocervix and ectocervix). Our results show that mouse endocervix has a higher proportion of smooth muscle cells and collagen fibers per area, with more compact tissue structure, than the ectocervix. With advanced gestation, endocervical changes, indicative of impending delivery, are manifested in fewer smooth muscle cells, expansion of the extracellular space, and lower presence of collagen fibers. MRI detected three distinctive zones in pregnant mouse endocervix: (1) inner collagenous layer, (2) middle circular muscular layer, and (3) outer longitudinal muscular layer. Diffusion MRI images detected changes in tissue organization as gestation progressed suggesting the potential application of this technique to non-invasively monitor cervical changes that precede the onset of labor in women at risk for preterm delivery.
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Affiliation(s)
- Antara Chatterjee
- Physiology, University of Toronto, Toronto, Canada
- Sinai Health System, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Rojan Saghian
- Medical Biophysics, University of Toronto, Toronto, Canada
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
| | - Anna Dorogin
- Sinai Health System, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Lindsay S Cahill
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
| | - John G Sled
- Medical Biophysics, University of Toronto, Toronto, Canada
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Obstetrics and Gynecology, University of Toronto, Toronto, Canada
| | - Stephen Lye
- Physiology, University of Toronto, Toronto, Canada
- Sinai Health System, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
- Obstetrics and Gynecology, University of Toronto, Toronto, Canada
| | - Oksana Shynlova
- Physiology, University of Toronto, Toronto, Canada.
- Sinai Health System, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.
- Obstetrics and Gynecology, University of Toronto, Toronto, Canada.
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24
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Hessami K, Kasraeian M, Sepúlveda-Martínez Á, Parra-Cordero MC, Vafaei H, Asadi N, Benito Vielba M. The Novel Ultrasonographic Marker of Uterocervical Angle for Prediction of Spontaneous Preterm Birth in Singleton and Twin Pregnancies: A Systematic Review and Meta-Analysis. Fetal Diagn Ther 2021; 48:1-7. [PMID: 33556952 DOI: 10.1159/000510648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/03/2020] [Indexed: 11/19/2022]
Abstract
The alteration of the uterocervical angle (UCA) has been proposed to play an important role in spontaneous preterm birth (sPTB). The aim of this systematic review and meta-analysis was to evaluate the evidence on the UCA predictive role in sPTB. In this study, PubMed, Web of Science, Scopus, and Google scholar were systematically searched from inception up to June 2020. Inter-study heterogeneity was also assessed using Cochrane's Q test and the I2 statistic. Afterward, the random-effects model was used to pool the weighted mean differences (WMDs) and the corresponding 95% confidence intervals (CIs). Eleven articles that reported second-trimester UCA of 5,061 pregnancies were included in this study. Our meta-analysis results indicate that a wider UCA significantly increases the risk of sPTB in following cases: all pregnancies (WMD = 15.25, 95% CI: 11.78-18.72, p < 0.001; I2 = 75.9%, p < 0.001), singleton (WMD = 14.43, 95% CI: 8.79-20.06, p < 0.001; I2 = 82.4%, p < 0.001), and twin pregnancies (WMD = 15.14, 95% CI: 13.42-16.87, p < 0.001; I2 = 0.0%, p = 0.464). A wider ultrasound-measured UCA in the second trimester seems to be associated with the increased risk of sPTB in both singleton and twin pregnancies, which reinforces the clinical evidence that UCA has the potential to be used as a predictive marker of sPTB.
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Affiliation(s)
- Kamran Hessami
- Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran,
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran,
| | - Maryam Kasraeian
- Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Álvaro Sepúlveda-Martínez
- Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology Hospital Clínico de la Universidad de Chile, Santiago de Chile, Chile
| | - Mauro Cristian Parra-Cordero
- Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology Hospital Clínico de la Universidad de Chile, Santiago de Chile, Chile
| | - Homeira Vafaei
- Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Nasrin Asadi
- Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Marta Benito Vielba
- Department of Obstetrics and Gynecology, Miguel Servet University Hospital, Zaragoza, Spain
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25
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Khamees RE, Khattab BM, Elshahat AM, Taha OT, Aboelroose AA. Uterocervical angle versus cervical length in the prediction of spontaneous preterm birth in singleton pregnancy. Int J Gynaecol Obstet 2021; 156:304-308. [PMID: 33507541 DOI: 10.1002/ijgo.13629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 12/02/2020] [Accepted: 01/25/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To evaluate the predictive role of the uterocervical angle and the cervical length in preterm birth. METHODS This was cross-sectional analytical study, recruiting 167 women at high-risk for preterm birth (delivery before 37 weeks of pregnancy). They had transvaginal ultrasound for evaluation of the uterocervical angle and the cervical length between at 30 and 32, 32+1 and 34, and 34+1 and 36+1 weeks of pregnancy. The primary outcome was to determine the predictive role of the uterocervical angle and the cervical length in preterm birth. RESULTS The mean uterocervical angle was significantly greater in those who delivered preterm (115.4° ± 9.1° versus 101.1° ± 8.3°, p < 0.001). The cervical length was insignificantly shorter in the same group (27.9 ± 4.0 and 29.1 ± 4.1 mm, respectively, p = 0.067). A uterocervical angle of 105° or more predicted preterm birth with sensitivity and specificity of 86.1% and 60.4%, respectively. A cervical length of 25 mm or less had sensitivity and specificity of 27.8% and 85.8%, respectively. CONCLUSION A uterocervical angle greater than 105° poses a high risk for preterm deliveries. It provides a higher diagnostic performance in high-risk patients than cervical canal length measurement.
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Affiliation(s)
- Rasha E Khamees
- Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Basma M Khattab
- Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Amal M Elshahat
- Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Omima T Taha
- Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Ahmed A Aboelroose
- Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
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26
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Lee W, Ostadi Moghaddam A, Shen S, Phillips H, McFarlin BL, Wagoner Johnson AJ, Toussaint KC. An optomechanogram for assessment of the structural and mechanical properties of tissues. Sci Rep 2021; 11:324. [PMID: 33431940 PMCID: PMC7801423 DOI: 10.1038/s41598-020-79602-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/24/2020] [Indexed: 11/25/2022] Open
Abstract
The structural and mechanical properties of tissue and the interplay between them play a critical role in tissue function. We introduce the optomechanogram, a combined quantitative and qualitative visualization of spatially co-registered measurements of the microstructural and micromechanical properties of any tissue. Our approach relies on the co-registration of two independent platforms, second-harmonic generation (SHG) microscopy for quantitative assessment of 3D collagen-fiber microstructural organization, and nanoindentation (NI) for local micromechanical properties. We experimentally validate our method by applying to uterine cervix tissue, which exhibits structural and mechanical complexity. We find statistically significant agreement between the micromechanical and microstructural data, and confirm that the distinct tissue regions are distinguishable using either the SHG or NI measurements. Our method could potentially be used for research in pregnancy maintenance, mechanobiological studies of tissues and their constitutive modeling and more generally for the optomechanical metrology of materials.
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Affiliation(s)
- W Lee
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - A Ostadi Moghaddam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
| | - S Shen
- Center for Health, Aging, and Disability (CHAD), College of Applied Health Science, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
| | - H Phillips
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - B L McFarlin
- Department of Women, Children and Family Health Science, University of Illinois College of Nursing, Chicago, IL, 60612, USA
| | - A J Wagoner Johnson
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA. .,Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA. .,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - K C Toussaint
- School of Engineering, Brown University, Providence, RI, 02912, USA.
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Callejas A, Melchor J, Faris IH, Rus G. Viscoelastic model characterization of human cervical tissue by torsional waves. J Mech Behav Biomed Mater 2020; 115:104261. [PMID: 33340778 DOI: 10.1016/j.jmbbm.2020.104261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 10/10/2020] [Accepted: 12/08/2020] [Indexed: 12/19/2022]
Abstract
The understanding of changes in the viscoelastic properties of cervical tissue during the gestation process is a challenging problem. In this work, we explore the importance of considering the multilayer nature (epithelial and connective layers) of human cervical tissue for characterizing the viscoelastic parameters from torsional waves. For this purpose, torsional wave propagations are simulated in three multilayer cervical tissue models (pure elastic, Kelvin-Voigt (KV) and Maxwell) using the finite difference time domain method. High-speed camera measurements have been carried out in tissue-mimicking phantoms in order to obtain the boundary conditions of the numerical simulations. Finally, a parametric modeling study through a probabilistic inverse procedure was performed to rank the most plausible rheological model and to reconstruct the viscoelastic parameters. The procedure consist in comparing the experimental signals obtained in human cervical tissues using the Torsional Wave Elastography (TWE) technique with the synthetic signals from the numerical models. It is shown that the rheological model that best describes the nature of cervical tissue is the Kelvin-Voigt model. Once the most plausible model has been selected, the stiffness and viscosity parameters have been reconstructed of the epithelial and connective layers for the measurements of the 18 pregnant women, along with the thickness of the epithelial layer.
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Affiliation(s)
- A Callejas
- Department of Structural Mechanics, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain.
| | - J Melchor
- Department of Structural Mechanics, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain; Excellence Research Unit "Modelling Nature" (MNat) University of Granada, Granada, Spain
| | - Inas H Faris
- Department of Structural Mechanics, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
| | - G Rus
- Department of Structural Mechanics, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain; Excellence Research Unit "Modelling Nature" (MNat) University of Granada, Granada, Spain
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28
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Gonzalez M, Montejo KA, Krupp K, Srinivas V, DeHoog E, Madhivanan P, Ramella-Roman JC. Design and implementation of a portable colposcope Mueller matrix polarimeter. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200109RR. [PMID: 33191686 PMCID: PMC7666868 DOI: 10.1117/1.jbo.25.11.116006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/21/2020] [Indexed: 05/07/2023]
Abstract
SIGNIFICANCE Mueller matrix polarimetry can provide useful information about the function and structure of the extracellular matrix. A portable and low-cost system could facilitate the clinical assessment of cervical anomalies in low-resource settings. AIM We introduce a low-cost snapshot Mueller matrix polarimeter that does not require external power, has no moving parts, and can acquire a full Mueller matrix in ∼1 s, to conduct a feasibility study for cervical imaging in the low-resource setting. APPROACH A snapshot system based on two sets of Savart plates, a ring illuminator with polarizing elements (generating four polarization states), and one camera is introduced. Stokes vectors are formulated to recover the polarization properties of the sample. Then, using Mueller matrix decomposition, the depolarization and retardance information is extracted. RESULTS We report the results on 16 healthy individuals (out of 22 patients imaged), whose Pap smear showed no malignant findings from mobile clinics in rural region of Mysore, India. The depolarization and retardance information was in agreement with previous reports. CONCLUSIONS We introduce an imaging system and conducted a feasibility study on healthy individuals. This work could futurely translate into diagnostic applications to provide a quantitative platform in the clinical environment (e.g., cervical cancer screening).
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Affiliation(s)
- Mariacarla Gonzalez
- Florida International University, Biomedical Engineering Department, Miami, Florida, United States
| | - Karla Alejandra Montejo
- Florida International University, Biomedical Engineering Department, Miami, Florida, United States
| | - Karl Krupp
- Public Health Research Institute of India, Mysore, Karnataka, India
- University of Arizona, Mel and Enid Zuckerman College of Public Health, Department of Health Promotion Sciences, Tucson, Arizona, United States
| | - Vijaya Srinivas
- Public Health Research Institute of India, Mysore, Karnataka, India
| | - Edward DeHoog
- Optical Engineering and Analysis, Long Beach, California, United States
| | - Purnima Madhivanan
- Public Health Research Institute of India, Mysore, Karnataka, India
- University of Arizona, Mel and Enid Zuckerman College of Public Health, Department of Health Promotion Sciences, Tucson, Arizona, United States
- University of Arizona, College of Medicine, Department of Medicine, Tucson, Arizona, United States
- University of Arizona, College of Medicine, Department of Family and Community Medicine, Tucson, Arizona, United States
| | - Jessica C. Ramella-Roman
- Florida International University, Biomedical Engineering Department, Miami, Florida, United States
- Florida International University, Herbert Wertheim College of Medicine Cellular Biology and Pharmacology, Department of Ophthalmology, Miami, Florida, United States
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29
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Xu Y, Liu H, Hao D, Taggart M, Zheng D. Uterus Modeling from Cell to Organ Level: towards Better Understanding of Physiological Basis of Uterine Activity. IEEE Rev Biomed Eng 2020; 15:341-353. [PMID: 32915747 DOI: 10.1109/rbme.2020.3023535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The relatively limited understanding of the physiology of uterine activation prevents us from achieving optimal clinical outcomes for managing serious pregnancy disorders such as preterm birth or uterine dystocia. There is increasing awareness that multi-scale computational modeling of the uterus is a promising approach for providing a qualitative and quantitative description of uterine physiology. The overarching objective of such approach is to coalesce previously fragmentary information into a predictive and testable model of uterine activity that, in turn, informs the development of new diagnostic and therapeutic approaches to these pressing clinical problems. This article assesses current progress towards this goal. We summarize the electrophysiological basis of uterine activation as presently understood and review recent research approaches to uterine modeling at different scales from single cell to tissue, whole organ and organism with particular focus on transformative data in the last decade. We describe the positives and limitations of these approaches, thereby identifying key gaps in our knowledge on which to focus, in parallel, future computational and biological research efforts.
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30
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Sawaddisan R, Kor-Anantakul O, Pruksanusak N, Geater A. Uterocervical angle measurement for preterm birth prediction in singleton pregnant women with no history of preterm birth and normal cervical length: A prospective cohort study. Eur J Obstet Gynecol Reprod Biol 2020; 252:30-35. [PMID: 32562939 DOI: 10.1016/j.ejogrb.2020.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To evaluate the ability of second trimester uterocervical angle (UCA) to predict spontaneous preterm birth (sPTB) in low-risk singleton pregnant women. STUDY DESIGN Transvaginal sonographies were performed in the second trimester of 450 singleton pregnant women with no history of sPTB and no history of second trimester miscarriage with normal cervical length (CL) who attended antenatal care at Songklanagarind Hospital, a tertiary teaching hospital in southern Thailand. Gestational ages at delivery were recorded then the UCA values were evaluated according to sPTB occurrence. The differences in mean values of UCA between sPTB and full-term groups were evaluated using t-test. A receiver operating characteristics (ROC) curve was used to assess the ability of UCA to predict sPTB. RESULTS After excluding women with unknown pregnancy outcomes or missing UCA images, the sPTB rate was 34/421 (8.1 %). In women with anteflexed uterus, the mean UCA value was wider in the sPTB group compared to those with term birth if the measurements were performed at GA 19.5-24 weeks (sPTB group, 123.4°vs controls, 104.3°; P = 0.017). The ROC curve showed an area under the curve (AUC) of 0.7045. The optimal UCA cut-off value was ≥110 degrees, which gave a sensitivity of 83.3 % and a specificity of 61.2 %. The positive predictive value (PPV) was 16.7 %, negative predictive value (NPV) 97.5 %, positive likelihood ratio (LR+) 2.2 and negative likelihood ratio (LR-) 0.3. CONCLUSION The UCA in the second trimester is not a good predictor of sPTB in low risk pregnant women.
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Affiliation(s)
- Rapphon Sawaddisan
- Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
| | - Ounjai Kor-Anantakul
- Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Ninlapa Pruksanusak
- Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Alan Geater
- Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
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31
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Shi L, Yao W, Gan Y, Zhao LY, Eugene McKee W, Vink J, Wapner RJ, Hendon CP, Myers K. Anisotropic Material Characterization of Human Cervix Tissue Based on Indentation and Inverse Finite Element Analysis. J Biomech Eng 2020; 141:2736280. [PMID: 31374123 DOI: 10.1115/1.4043977] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 11/08/2022]
Abstract
The cervix is essential to a healthy pregnancy as it must bear the increasing load caused by the growing fetus. Preterm birth is suspected to be caused by the premature softening and mechanical failure of the cervix. The objective of this paper is to measure the anisotropic mechanical properties of human cervical tissue using indentation and video extensometry. The human cervix is a layered structure, where its thick stromal core contains preferentially aligned collagen fibers embedded in a soft ground substance. The fiber composite nature of the tissue provides resistance to the complex three-dimensional loading environment of pregnancy. In this work, we detail an indentation mechanical test to obtain the force and deformation response during loading which closely matches in vivo conditions. We postulate a constitutive material model to describe the equilibrium material behavior to ramp-hold indentation, and we use an inverse finite element method based on genetic algorithm (GA) optimization to determine best-fit material parameters. We report the material properties of human cervical slices taken at different anatomical locations from women of different obstetric backgrounds. In this cohort of patients, the anterior internal os (the area where the cervix meets the uterus) of the cervix is stiffer than the anterior external os (the area closest to the vagina). The anatomic anterior and posterior quadrants of cervical tissue are more anisotropic than the left and right quadrants. There is no significant difference in material properties between samples of different parities (number of pregnancies reaching viable gestation age).
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Affiliation(s)
- Lei Shi
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Wang Yao
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Yu Gan
- Department of Electrical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Lily Y Zhao
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - W Eugene McKee
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Joy Vink
- Department of Obstetrics and Gynecology, Columbia University, New York, NY 10032 e-mail:
| | - Ronald J Wapner
- Department of Obstetrics and Gynecology, Columbia University, New York, NY 10032 e-mail:
| | - Christine P Hendon
- Department of Electrical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Kristin Myers
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
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32
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Sawaddisan R, Kor-Anantakul O, Pruksanusak N, Geater A. Distribution of uterocervical angles in the second trimester of pregnant women at low risk for preterm delivery. J OBSTET GYNAECOL 2020; 41:77-82. [PMID: 32148135 DOI: 10.1080/01443615.2020.1718622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The uterocervical angle (UCA) has recently been studied as a parameter to identify women at risk for spontaneous preterm birth (sPTB). This study aimed to investigate the distribution of UCA values by transvaginal sonography (TVS) in the second trimester of women at low risk for sPTB. TVS was performed in 450 low-risk pregnant women at gestational age (GA) 160/7-240/7 weeks. The UCA distribution by GA was visualised using a scatter plot. The range of UCA values and their relationship with GA were assessed using quantile regression analysis. p < .05 was considered statistically significant. A total of 242 participants with anteflexed uterus, no history of caesarean section and term delivery were analysed. The normal range of UCA (5th and 95th percentiles) was from 63.0 degrees (95% CI, 53.1-72.9) to 148.8 degrees (95% CI, 139.5-158.0) with no significant changes during this GA period (-0.3 degrees per week, p = .757).Impact statementWhat is already known on this subject? Spontaneous preterm birth (sPTB) is a major problem in obstetrics. A screening strategy using history of sPTB and cervical length (CL) measurement is the current standard to identify women at risk for sPTB and provide adequate prevention. However, a third of women who are identified as low risk go on to have sPTB, so a better means needs to be found to more reliably identify women at risk. Various studies have found that a wide uterocervical angle (UCA) was associated with sPTB, and thus the UCA has been proposed as a potential sPTB screening parameter. However, to date there is a lack of prospective studies evaluating this proposal, and no consensus about the proper gestational age to perform UCA measurements to identify women at risk of sPTB.What do the results of this study add? This study reports the distribution of UCA at the GA of 160/7-240/7 weeks of low-risk singleton pregnancy women who delivered at term. The mid-90% values ranged from 63.0 degrees to 148.8 degrees with no significant differences in this GA period.What are the implications of these findings for clinical practice and/or further research? Because of the wide range of UCA values at GA 160/7-240/7 weeks, more studies regarding UCA values in various gestational ages are required to fully understand the trend of UCA values along pregnancy and confirm whether or not the UCA would be a useful parameter for sPTB prediction and if so at what gestational age it would have to be assessed.
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Affiliation(s)
- Rapphon Sawaddisan
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Ounjai Kor-Anantakul
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Ninlapa Pruksanusak
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Alan Geater
- Department of Epidemiology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
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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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Koullali B, Zhang Y, Peterson A, Raia N, Kaplan DL, House MD. Cervical Augmentation with an Injectable Silk-Based Gel: Biocompatibility in a Rat Model of Pregnancy. Reprod Sci 2020; 27:1215-1221. [PMID: 32046447 DOI: 10.1007/s43032-019-00111-7] [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: 07/02/2019] [Accepted: 11/01/2019] [Indexed: 11/25/2022]
Abstract
The aim of this study was to study the biocompatibility of an injectable silk gel in the cervix in a rat model of pregnancy. The rationale is to study an injectable gel as an alternate treatment for cervical insufficiency. We further aimed to perform cervical injections via a vaginal route to mimic the clinical procedure of a cervical cerclage. We performed an in vivo study in pregnant female Sprague Dawley rats. Cervical procedures were performed using a customized speculum under general anesthesia. Injections were performed on gestational day 16. The responses to silk gel injections were compared to polyethylene terephthalate suture and saline controls on gestational day 19 and postpartum. The inflammatory response was evaluated by histology, PCR for inflammatory gene expression, and ELISA for protein levels of proinflammatory mediators. Silk gel injections were performed on 13 animals. All animals tolerated the procedure. Silk gel occupied 5% of the stroma after injection. Injected silk gel caused neither preterm birth nor prolonged pregnancy and had no effect on the kits. When comparing inflammatory responses, expression of inflammatory genes and proinflammatory proteins in the silk gel group was intermediate between saline (lowest) and cerclage suture (highest). Injectable silk gel was more inflammatory compared to saline injections but less inflammatory compared to the suture material used for cervical cerclage. This study is an important step toward development of an alternative treatment for cervical insufficiency.
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Affiliation(s)
- Bouchra Koullali
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, USA
- Department of Obstetrics and Gynecology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam, Netherlands
| | - Yali Zhang
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, USA
| | - Ashley Peterson
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA
| | - Nicole Raia
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - Michael D House
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, USA.
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA.
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Menon R, Moore JJ. Fetal Membranes, Not a Mere Appendage of the Placenta, but a Critical Part of the Fetal-Maternal Interface Controlling Parturition. Obstet Gynecol Clin North Am 2019; 47:147-162. [PMID: 32008665 DOI: 10.1016/j.ogc.2019.10.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Fetal membranes (FMs) play a role in pregnancy maintenance and promoting parturition at term. The FMs are not just part of the placenta, structurally or functionally. Although attached to the placenta, the amnion has a separate embryologic origin, and the chorion deviates from the placenta by the first month of pregnancy. Other than immune protection, these FM functions are not those of the placenta. FM dysfunction is associated with and may cause adverse pregnancy outcomes. Ongoing research may identify biomarkers for pending preterm premature rupture of the FMs as well as therapeutic agents, to prevent it and resulting preterm birth.
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Affiliation(s)
- Ramkumar Menon
- Department of Obstetrics and Gynecology, Perinatal Research Division, The University of Texas Medical Branch, MRB 11.138, 301 University Boulevard, Galveston, TX 77555, USA
| | - John J Moore
- Case Western Reserve University School of Medicine, 2500 MetroHealth Drive, Cleveland, OH 44109, USA.
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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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Feltovich H. Labour and delivery: a clinician's perspective on a biomechanics problem. Interface Focus 2019; 9:20190032. [PMID: 31485317 PMCID: PMC6710663 DOI: 10.1098/rsfs.2019.0032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2019] [Indexed: 12/12/2022] Open
Abstract
Predicting how and when a pregnant woman will deliver her fetus has always been a problem for the clinician, and, consequently, there has been little progress made in preventing poor outcomes from pregnancies that deliver too soon or too late. In the opinion of the author, a maternal-fetal medicine specialist, rethinking labour within a biomechanical framework and studying it like an engineering problem could be a promising approach to unlocking the mysteries of labour.
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Affiliation(s)
- Helen Feltovich
- Maternal Fetal Medicine, Intermountain Health Care, Salt Lake City, UT 84111-1453, USA
- Medical Physics, University of Wisconsin Madison, 1003 WIMR, 1111 Highland Avenue, Madison, WI 53706, USA
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38
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Bircher K, Ehret AE, Spiess D, Ehrbar M, Simões-Wüst AP, Ochsenbein-Kölble N, Zimmermann R, Mazza E. On the defect tolerance of fetal membranes. Interface Focus 2019; 9:20190010. [PMID: 31485307 DOI: 10.1098/rsfs.2019.0010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2019] [Indexed: 11/12/2022] Open
Abstract
A series of mechanical experiments were performed to quantify the strength and fracture toughness of human amnion and chorion. The experiments were complemented with computational investigations using a 'hybrid' model that includes an explicit representation of the collagen fibre network of amnion. Despite its much smaller thickness, amnion is shown to be stiffer, stronger and tougher than chorion, and thus to determine the mechanical response of fetal membranes, with respect to both, deformation and fracture behaviour. Data from uniaxial tension and fracture tests were used to inform and validate the computational model, which was then applied to rationalize measurements of the tear resistance of tissue samples containing crack-like defects. Experiments and computations show that the strength of amnion is not significantly reduced by defects smaller than 1 mm, but the crack size induced by perforations for amniocentesis and fetal membrane suturing during fetal surgery might be larger than this value. In line with previous experimental observations, the computational model predicts a very narrow near field at the crack tip of amnion, due to localized fibre alignment and collagen compaction. This mechanism shields the tissue from the defect and strongly reduces the interaction of multiple adjacent cracks. These findings were confirmed through corresponding experiments, showing that no interaction is expected for multiple sutures for an inter-suture distance larger than 1 mm and 3 mm for amnion and chorion, respectively. The experimental procedures and numerical models applied in the present study might be used to optimize needle and/or staple dimensions and inter-suture distance, and thus to reduce the risk of iatrogenic preterm premature rupture of the membranes from amniocentesis, fetoscopic and open prenatal surgery.
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Affiliation(s)
- Kevin Bircher
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland
| | - Alexander E Ehret
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland.,Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Deborah Spiess
- Department of Obstetrics, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Martin Ehrbar
- Department of Obstetrics, University Hospital Zurich, 8091 Zurich, Switzerland
| | | | | | - Roland Zimmermann
- Department of Obstetrics, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Edoardo Mazza
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland.,Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
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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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40
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Eser A, Ozkaya E. Uterocervical angle: an ultrasound screening tool to predict satisfactory response to labor induction. J Matern Fetal Neonatal Med 2018; 33:1295-1301. [PMID: 30249147 DOI: 10.1080/14767058.2018.1517324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Background: A wide uterocervical angle >95° detected during the second trimester was associated with an increased risk for spontaneous preterm birth.Objective: We aimed to determine whether an ultrasonographic marker, uterocervical angle, correlates with satisfactory response to labor induction.Study design: We conducted a prospective cohort study from May 2016 through December 2017 of singleton term gestations undergoing transvaginal ultrasound for cervical length screening and uterocervical angle measurement. Uterocervical angle was measured between the lower uterine segment and the cervical canal. Latent phase duration >720 min was accepted to be a prolonged latent phase. The primary outcome was a prediction of satisfactory response to labor induction (latent phase duration <720 min).Results: Both anterior uterocervical angle (AUC = 0.802, p < .001) and the cervical length (AUC = 0.679, p < .05) significantly predicted satisfactory response to labor induction. Optimal cutoff value was obtained at the value of 97° (64% sensitivity, 91% specificity) for anterior uterocervical angle and 27 mm (64% sensitivity, 64% specificity) for the cervical length. Kaplan-Meier survival analysis showed that duration from labor induction to delivery was significantly higher in a group with longer cervical length (p = .04), additionally labor induction to delivery time was significantly higher in a group with lower UCA (p = .04).Conclusions: Both the cervical length and anterior uterocervical length were predictors for the satisfactory response to labor induction, and both parameters were found to be significantly associated with time from induction to delivery in survival analysis.
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Affiliation(s)
- Ahmet Eser
- Department of Obstetrics and Gynecology, Zeynep Kamil Women and Children's Health Training and Research Hospital, Istanbul, Turkey
| | - Enis Ozkaya
- Department of Obstetrics and Gynecology, Zeynep Kamil Women and Children's Health Training and Research Hospital, Istanbul, Turkey
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41
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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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Chue-Sang J, Holness N, Gonzalez M, Greaves J, Saytashev I, Stoff S, Gandjbakhche A, Chernomordik VV, Burkett G, Ramella-Roman JC. Use of Mueller matrix colposcopy in the characterization of cervical collagen anisotropy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-9. [PMID: 30088376 PMCID: PMC8357193 DOI: 10.1117/1.jbo.23.12.121605] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/23/2018] [Indexed: 05/18/2023]
Abstract
Annually, about 15 million preterm infants are born in the world. Of these, due to complications resulting from their premature birth, about 1 million would die before the age of five. Since the high incidence of preterm birth (PTB) is partially due to the lack of effective diagnostic modalities, methodologies are needed to determine risk of PTB. We propose a noninvasive tool based on polarized light imaging aimed at measuring the organization of collagen in the cervix. Cervical collagen has been shown to remodel with the approach of parturition. We used a full-field Mueller matrix polarimetric colposcope to assess and compare cervical collagen content and structure in nonpregnant and pregnant women in vivo. Local collagen directional azimuth was used and a total of eight cervices were imaged.
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Affiliation(s)
- Joseph Chue-Sang
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Nola Holness
- Florida International University, Nicole Wertheim College of Nursing and Health Sciences, Miami, Florida, United States
| | - Mariacarla Gonzalez
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Joan Greaves
- Jackson Memorial Hospital, Holtz Children’s Hospital, Miami, Florida, United States
| | - Ilyas Saytashev
- Florida International University, Herbert Wertheim College of Medicine, Miami, Florida, United States
| | - Susan Stoff
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Amir Gandjbakhche
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Maryland, United States
| | - Viktor V. Chernomordik
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Maryland, United States
| | - Gene Burkett
- University of Miami, Leonard Miller School of Medicine, Department of Obstetrics and Gynecology, Miami, Florida, United States
| | - Jessica C. Ramella-Roman
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
- Florida International University, Herbert Wertheim College of Medicine, Miami, Florida, United States
- Address all correspondence to: Jessica C. Ramella-Roman, E-mail:
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Guerrero QW, Feltovich H, Rosado-Mendez IM, Carlson LC, Li G, Hall TJ. Anisotropy and Spatial Heterogeneity in Quantitative Ultrasound Parameters: Relevance to the Study of the Human Cervix. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1493-1503. [PMID: 29661482 PMCID: PMC5960605 DOI: 10.1016/j.ultrasmedbio.2018.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/20/2018] [Accepted: 02/22/2018] [Indexed: 05/13/2023]
Abstract
Imaging biomarkers based on quantitative ultrasound can offer valuable information about properties that inform tissue function and behavior such as microstructural organization (e.g., collagen alignment) and viscoelasticity (i.e., compliance). For example, the cervix feels softer as its microstructure remodels during pregnancy, an increase in compliance that can be objectively quantified with shear wave speed and therefore shear wave speed estimation is a potential biomarker of cervical remodeling. Other proposed biomarkers include parameters derived from the backscattered echo signal, such as attenuation and backscattered power loss, because such parameters can provide insight into tissue microstructural alignment and organization. Of these, attenuation values for the pregnant cervix have been reported, but large estimate variance reduces their clinical value. That said, parameter estimates based on the backscattered echo signal may be incorrect if assumptions they rely on, such as tissue isotropy and homogeneity, are violated. For that reason, we explored backscatter and attenuation parameters as potential biomarkers of cervical remodeling via careful investigation of the assumptions of isotropy and homogeneity in cervical tissue. Specifically, we estimated the angle- and spatial-dependence of parameters of backscattered power and acoustic attenuation in the ex vivo human cervix, using the reference phantom method and electronic steering of the ultrasound beam. We found that estimates are anisotropic and spatially heterogeneous, presumably because the tissue itself is anisotropic and heterogeneous. We conclude that appropriate interpretation of imaging biomarkers of cervical remodeling must account for tissue anisotropy and heterogeneity.
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Affiliation(s)
| | - Helen Feltovich
- Medical Physics Department, University of Wisconsin, Madison, WI, USA; Maternal Fetal Medicine, Obstetrics & Gynecology, Intermountain Healthcare, Provo, UT, USA
| | | | - Lindsey C Carlson
- Medical Physics Department, University of Wisconsin, Madison, WI, USA; Maternal Fetal Medicine, Obstetrics & Gynecology, Intermountain Healthcare, Provo, UT, USA
| | - Geng Li
- Biostatistics and Medical Informatics Department, University of Wisconsin, Madison, WI, USA
| | - Timothy J Hall
- Medical Physics Department, University of Wisconsin, Madison, WI, USA.
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44
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Hao J, Yao W, Harris WBR, Vink JY, Myers KM, Donnelly E. Characterization of the collagen microstructural organization of human cervical tissue. Reproduction 2018; 156:71-79. [PMID: 29712877 DOI: 10.1530/rep-17-0763] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/30/2018] [Indexed: 11/08/2022]
Abstract
The cervix shortens and softens as its collagen microstructure remodels in preparation for birth. Altered cervical tissue collagen microstructure can contribute to a mechanically weak cervix and premature cervical dilation and delivery. To investigate the local microstructural changes associated with anatomic location and pregnancy, we used second-harmonic generation microscopy to quantify the orientation and spatial distribution of collagen throughout cervical tissue from 4 pregnant and 14 non-pregnant women. Across patients, the alignment and concentration of collagen within the cervix was more variable near the internal os and less variable near the external os. Across anatomic locations, the spatial distribution of collagen within a radial zone adjacent to the inner canal of the cervix was more homogeneous than that of a region comprising the middle and outer radial zones. Two regions with different collagen distribution characteristics were found. The anterior and posterior sections in the outer radial zone were characterized by greater spatial heterogeneity of collagen than that of the rest of the sections. Our findings suggest that the microstructural alignment and distribution of collagen varies with anatomic location within the human cervix. These observed differences in collagen microstructural alignment may reflect local anatomic differences in cervical mechanical loading and function. Our study deepens the understanding of specific microstructural cervical changes in pregnancy and informs investigations of potential mechanisms for normal and premature cervical remodeling.
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Affiliation(s)
- Jia Hao
- Department of Materials Science and EngineeringCornell University, Ithaca, New York, USA
| | - Wang Yao
- Department of Mechanical EngineeringColumbia University, New York, New York, USA
| | - W B Ryan Harris
- Department of Materials Science and EngineeringCornell University, Ithaca, New York, USA
| | - Joy Y Vink
- Department of Obstetrics and GynecologyColumbia University Medical Center, New York, New York, USA
| | - Kristin M Myers
- Department of Mechanical EngineeringColumbia University, New York, New York, USA
| | - Eve Donnelly
- Department of Materials Science and EngineeringCornell University, Ithaca, New York, USA .,Research DivisionHospital for Special Surgery, New York, New York, USA
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45
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Rosado-Mendez IM, Carlson LC, Woo KM, Santoso AP, Guerrero QW, Palmeri ML, Feltovich H, Hall TJ. Quantitative assessment of cervical softening during pregnancy in the Rhesus macaque with shear wave elasticity imaging. Phys Med Biol 2018. [PMID: 29517492 DOI: 10.1088/1361-6560/aab532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abnormal parturition, e.g. pre- or post-term birth, is associated with maternal and neonatal morbidity and increased economic burden. This could potentially be prevented by accurate detection of abnormal softening of the uterine cervix. Shear wave elasticity imaging (SWEI) techniques that quantify tissue softness, such as shear wave speed (SWS) measurement, are promising for evaluation of the cervix. Still, interpretation of results can be complicated by biological variability (i.e. spatial variations of cervix stiffness, parity), as well as by experimental factors (i.e. type of transducer, posture during scanning). Here we investigated the ability of SWEI to detect cervical softening, as well as sources of SWS variability that can affect this task, in the pregnant and nonpregnant Rhesus macaque. Specifically, we evaluated SWS differences when imaging the cervix transabdominally with a typical linear array abdominal transducer, and transrectally with a prototype intracavitary linear array transducer. Linear mixed effects (LME) models were used to model SWS as a function of menstrual cycle day (in nonpregnant animals) and gestational age (in pregnant animals). Other variables included parity, shear wave direction, and cervix side (anterior versus posterior). In the nonpregnant cervix, the LME model indicated that SWS increased by 2% (95% confidence interval 0-3%) per day, starting eight days before menstruation. During pregnancy, SWS significantly decreased at a rate of 6% (95% CI 5-7%) per week (intracavitary approach) and 3% (95% CI 2-4%) per week (transabdominal approach), and interactions between the scanning approach and other fixed effects were also significant. These results suggest that, while absolute SWS values are influenced by factors such as scanning approach and SWEI implementation, these sources of variability do not compromise the sensitivity of SWEI to cervical softening. Our results also highlight the importance of standardizing SWEI approaches to improve their accuracy for cervical assessment.
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Affiliation(s)
- Ivan M Rosado-Mendez
- Medical Physics Department, University of Wisconsin, Madison, WI, United States of America. Present address: Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
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Abstract
The mechanical integrity of the soft tissue structures supporting the fetus may play a role in maintaining a healthy pregnancy and triggering the onset of labor. Currently, the level of mechanical loading on the uterus, cervix, and fetal membranes during pregnancy is unknown, and it is hypothesized that the over-stretch of these tissues contributes to the premature onset of contractility, tissue remodeling, and membrane rupture, leading to preterm birth. The purpose of this review article is to introduce and discuss engineering analysis tools to evaluate and predict the mechanical loads on the uterus, cervix, and fetal membranes. Here we will explore the potential of using computational biomechanics and finite element analysis to study the causes of preterm birth and to develop a diagnostic tool that can predict gestational outcome. We will define engineering terms and identify the potential engineering variables that could be used to signal an abnormal pregnancy. We will discuss the translational ability of computational models for the better management of clinical patients. We will also discuss the process of model validation and the limitations of these models. We will explore how we can borrow from parallel engineering fields to push the boundary of patient care so that we can work toward eliminating preterm birth.
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Affiliation(s)
- Andrea R Westervelt
- Department of Mechanical Engineering, School of Engineering and Applied Science, Columbia University, 500 W, 120th St, Mudd 220, New York, NY 10027
| | - Kristin M Myers
- Department of Mechanical Engineering, School of Engineering and Applied Science, Columbia University, 500 W, 120th St, Mudd 220, New York, NY 10027.
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47
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Abstract
The process of parturition is poorly understood, but the cervix clearly plays a key role. Because of this, recent research efforts have been directed at objective quantification of cervical remodeling. Investigation has focused on two basic areas: (1) quantification of tissue deformability and (2) presence, orientation, and/or concentration of microstructural components (e.g. collagen). Methods to quantify tissue deformability include strain elastography and shear wave elasticity imaging (SWEI). Methods to describe tissue microstructure include attenuation and backscatter. A single parameter is unlikely to describe the complexities of cervical remodeling, but combining related parameters should improve accuracy of cervical evaluation. This chapter reviews options for cervical tissue characterization.
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Affiliation(s)
- Helen Feltovich
- Maternal Fetal Medicine, Intermountain Healthcare, Utah Valley Hospital, 1034 N 500 W, Provo, UT 84604.
| | - Lindsey Drehfal
- Medical Physics, University of Wisconsin-Madison, Madison WI
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48
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Abstract
Preterm birth is the leading cause of neonatal mortality and morbidity worldwide. Spontaneous preterm birth is a complex, multifactorial condition in which cervical dysfunction plays an important role in some women. Current treatment options for cervical dysfunction include cerclage and supplemental progesterone. In addition, cervical pessary is being studied in research protocols. However, cerclage, supplemental progesterone and cervical pessary have well known limitations and there is a strong need for alternate treatment options. In this review, we discuss two novel interventions to treat cervical dysfunction: (1) injectable, silk protein-based biomaterials for cervical tissue augmentation (injectable cerclage) and (2) a patient-specific pessary. Three-dimensional computer simulation of the cervix is performed to provide a biomechanical rationale for the interventions. Further development of these novel interventions could lead to new treatment options for women with cervical dysfunction.
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Affiliation(s)
- Bouchra Koullali
- Tufts Medical Center, Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, 800 Washington St, Boston, MA 02111; Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
| | | | - Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY
| | - Michael D House
- Tufts Medical Center, Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, 800 Washington St, Boston, MA 02111.
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Westervelt AR, Fernandez M, House M, Vink J, Nhan-Chang CL, Wapner R, Myers KM. A Parameterized Ultrasound-Based Finite Element Analysis of the Mechanical Environment of Pregnancy. J Biomech Eng 2017; 139:2612939. [PMID: 28303276 DOI: 10.1115/1.4036259] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 11/08/2022]
Abstract
Preterm birth is the leading cause of childhood mortality and can lead to health risks in survivors. The mechanical functions of the uterus, fetal membranes, and cervix have dynamic roles to protect the fetus during gestation. To understand their mechanical function and relation to preterm birth, we built a three-dimensional parameterized finite element model of pregnancy. This model is generated by an automated procedure that is informed by maternal ultrasound measurements. A baseline model at 25 weeks of gestation was characterized, and to visualize the impact of cervical structural parameters on tissue stretch, we evaluated the model sensitivity to (1) anterior uterocervical angle, (2) cervical length, (3) posterior cervical offset, and (4) cervical stiffness. We found that cervical tissue stretching is minimal when the cervical canal is aligned with the longitudinal uterine axis, and a softer cervix is more sensitive to changes in the geometric variables tested.
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Affiliation(s)
- Andrea R Westervelt
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Michael Fernandez
- Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
| | - Michael House
- Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA 02111 e-mail:
| | - Joy Vink
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032 e-mail:
| | - Chia-Ling Nhan-Chang
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032 e-mail:
| | - Ronald Wapner
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032 e-mail:
| | - Kristin M Myers
- Mem. ASME Department of Mechanical Engineering, Columbia University, New York, NY 10027 e-mail:
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Cellular Mechanics of Primary Human Cervical Fibroblasts: Influence of Progesterone and a Pro-inflammatory Cytokine. Ann Biomed Eng 2017; 46:197-207. [PMID: 28939933 DOI: 10.1007/s10439-017-1935-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/20/2017] [Indexed: 01/08/2023]
Abstract
The leading cause of neonatal mortality, pre-term birth, is often caused by pre-mature ripening/opening of the uterine cervix. Although cervical fibroblasts play an important role in modulating the cervix's extracellular matrix (ECM) and mechanical properties, it is not known how hormones, i.e., progesterone, and pro-inflammatory insults alter fibroblast mechanics, fibroblast-ECM interactions and the resulting changes in tissue mechanics. Here we investigate how progesterone and a pro-inflammatory cytokine, IL-1β, alter the biomechanical properties of human cervical fibroblasts and the fibroblast-ECM interactions that govern tissue-scale mechanics. Primary human fibroblasts were isolated from non-pregnant cervix and treated with estrogen/progesterone, IL-1β or both. The resulting changes in ECM gene expression, matrix remodeling, traction force generation, cell-ECM adhesion and tissue contractility were monitored. Results indicate that IL-1β induces a significant reduction in traction force and ECM adhesion independent of pre-treatment with progesterone. These cell level effects altered tissue-scale mechanics where IL-1β inhibited the contraction of a collagen gel over 6 days. Interestingly, progesterone treatment alone did not modulate traction forces or gel contraction but did result in a dramatic increase in cell-ECM adhesion. Therefore, the protective effect of progesterone may be due to altered adhesion dynamics as opposed to altered ECM remodeling.
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