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White SE, Karbasion N, Snider JC, Florian-Rodriguez M, Bersi MR, Miller KS. Remodeling of murine vaginal smooth muscle function with reproductive age and elastic fiber disruption. Acta Biomater 2024; 175:186-198. [PMID: 38151068 DOI: 10.1016/j.actbio.2023.12.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023]
Abstract
Advanced maternal age during pregnancy is associated with increased risk of vaginal tearing during delivery and maladaptive postpartum healing. Although the underlying mechanisms of age-related vaginal injuries are not fully elucidated, changes in vaginal microstructure may contribute. Smooth muscle cells promote the contractile nature of the vagina and contribute to pelvic floor stability. While menopause is associated with decreased vaginal smooth muscle content, whether contractile changes occur before the onset of menopause remains unknown. Therefore, the first objective of this study was to quantify the active mechanical behavior of the murine vagina with age. Further, aging is associated with decreased vaginal elastin content. As such, the second objective was to determine if elastic fiber disruption alters vaginal contractility. Vaginal samples from mice aged 2-14 months were used in maximum contractility experiments and biaxial extension-inflation protocols. To evaluate the role of elastic fibers with age, half of the vaginal samples were randomly allocated to enzymatic elastic fiber disruption. Contractile potential decreased and vaginal material stiffness increased with age. These age-related changes in smooth muscle function may be due, in part, to changes in microstructural composition or contractile gene expression. Furthermore, elastic fiber disruption had a diminished effect on smooth muscle contractility in older mice. This suggests a decreased functional role of elastic fibers with age. Quantifying the age-dependent mechanical contribution of smooth muscle cells and elastic fibers to vaginal properties provides a first step towards better understanding how age-related changes in vaginal structure may contribute to tissue integrity and healing. STATEMENT OF SIGNIFICANCE: Advanced maternal age at the time of pregnancy is linked to increased risks of vaginal tearing during delivery, postpartum hemorrhaging, and the development of pelvic floor disorders. While the underlying causes of increased vaginal injuries with age and associated pathologies remain unclear, changes in vaginal microstructure, such as elastic fibers and smooth muscle cells, may contribute. Menopause is associated with fragmented elastic fibers and decreased smooth muscle content; however, how reproductive aging affects changes in the vaginal composition and the mechanical properties remains unknown. Quantifying the mechanical contribution of smooth muscle cells and elastic fibers to vaginal properties with age will advance understanding of the potential structural causes of age-related changes to tissue integrity and healing.
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Affiliation(s)
- Shelby E White
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Niyousha Karbasion
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - J Caleb Snider
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - Maria Florian-Rodriguez
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew R Bersi
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - Kristin S Miller
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX, USA; Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA.
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Yang L, Xie F, Li Y, Lu Y, Li B, Hong S, Tang J, Liu J, Cheng J, He Y, Zhang Z, Zhang S, Chen M, Li L, Yao L, Yan S, Cai J, Hong L. Chitin-based hydrogel loaded with bFGF and SDF-1 for inducing endogenous mesenchymal stem cells homing to improve stress urinary incontinence. Carbohydr Polym 2023; 319:121144. [PMID: 37567701 DOI: 10.1016/j.carbpol.2023.121144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/17/2023] [Accepted: 06/22/2023] [Indexed: 08/13/2023]
Abstract
Nonoperative treatments for Stress Urinary Incontinence (SUI) represent an ideal treatment method. Mesenchymal stem cell (MSCs) treatment is a new modality, but there is a lack of research in the field of gynecological pelvic floor and no good method to induce internal MSC homing to improve SUI. Herein, we develop an injectable and self-healing hydrogel derived from β-chitin which consists of an amino group of quaternized β-chitin (QC) and an aldehyde group of oxidized dextran (OD) between the dynamic Schiff base linkage.it can carry bFGF and SDF-1a and be injected into the vaginal forearm of mice in a non-invasive manner. It provides sling-like physical support to the anterior vaginal wall in the early stages. In the later stage, it slowly releasing factors and promoting the homing of MSCs in vivo, which can improve the local microenvironment, increase collagen deposition, repair the tissue around urethra and finally improve SUI (Scheme 1). This is the first bold attempt in the field of pelvic floor using hydrogel mechanical support combined with MSCs homing and the first application of chitin hydrogel in gynecology. We think the regenerative medicine approach based on bFGF/SDF-1/chitin hydrogel may be an effective non-surgical approach to combat clinical SUI.
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Affiliation(s)
- Lian Yang
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Fang Xie
- College of Chemistry & Molecular Sciences, Wuhan University, Hubei Engineering Center of Natural Polymers-based Medical Materials, Wuhan, 430072, People's Republic of China
| | - Yang Li
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Yiwen Lu
- College of Chemistry & Molecular Sciences, Wuhan University, Hubei Engineering Center of Natural Polymers-based Medical Materials, Wuhan, 430072, People's Republic of China
| | - Bingshu Li
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Shasha Hong
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Jianming Tang
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Jianfeng Liu
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Jianhong Cheng
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Yong He
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Zihui Zhang
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Shufei Zhang
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Mao Chen
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Lu Li
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Lichao Yao
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Sisi Yan
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China
| | - Jie Cai
- College of Chemistry & Molecular Sciences, Wuhan University, Hubei Engineering Center of Natural Polymers-based Medical Materials, Wuhan, 430072, People's Republic of China.
| | - Li Hong
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei Province 430060, People's Republic of China.
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Clark-Patterson GL, Buchanan LM, Ogola BO, Florian-Rodriguez M, Lindsey SH, De Vita R, Miller KS. Smooth muscle contribution to vaginal viscoelastic response. J Mech Behav Biomed Mater 2023; 140:105702. [PMID: 36764168 DOI: 10.1016/j.jmbbm.2023.105702] [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: 11/09/2022] [Revised: 01/22/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
Smooth muscle cells contribute to the mechanical function of various soft tissues, however, their contribution to the viscoelastic response when subjected to multiaxial loading remains unknown. The vagina is a fibromuscular viscoelastic organ that is exposed to prolonged and increased pressures with daily activities and physiologic processes such as vaginal birth. The vagina changes in geometry over time under prolonged pressure, known as creep. Vaginal smooth muscle cells may contribute to creep. This may be critical for the function of vaginal and other soft tissues that experience fluctuations in their biomechanical environment. Therefore, the objective of this study was to develop methods to evaluate the contribution of smooth muscle to vaginal creep under multiaxial loading using extension - inflation tests. The vaginas from wildtype mice (C57BL/6 × 129SvEv; 3-6 months; n = 10) were stimulated with various concentrations of potassium chloride then subjected to the measured in vivo pressure (7 mmHg) for 100 s. In a different cohort of mice (n = 5), the vagina was stimulated with a single concentration of potassium chloride then subjected to 5 and 15 mmHg. A laser micrometer measured vaginal outer diameter in real-time. Immunofluorescence evaluated the expression of alpha-smooth muscle actin and myosin heavy chain in the vaginal muscularis (n = 6). When smooth muscle contraction was activated, vaginal creep behavior increased compared to the relaxed state. However, increased pressure decreased the active creep response. This study demonstrated that extension - inflation protocols can be used to evaluate smooth muscle contribution to the viscoelastic response of tubular soft tissues.
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Affiliation(s)
| | - Lily M Buchanan
- University of Texas at Dallas, Department of Bioengineering, 800 W. Campbell Road, Richardson, TX, 75080, USA.
| | - Benard O Ogola
- Augusta University, Vascular Biology Center, Medical College of Georgia at Augusta University, 1460 Laney Walker Blvd, Augusta, GA, 30912, USA.
| | - Maria Florian-Rodriguez
- University of Texas Southwestern Medical Center, Department of Obstetrics and Gynecology, Division of Female Pelvic Medicine and Reconstructive Surgery and Cecil H and Ida Green Center for Reproductive Biological Sciences, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9032, USA.
| | - Sarah H Lindsey
- Tulane University School of Medicine, Department of Pharmacology, 1430 Tulane Ave, New Orleans, LA, 70112, USA.
| | - Raffaella De Vita
- Virginia Tech,Department of Biomedical Engineering and Mechanics, 330 A Kelly Hall, 325 Stanger St, Blacksburg, VA, 24061, USA.
| | - Kristin S Miller
- Tulane University, Department of Biomedical Engineering, 6823 St Charles Ave, New Orleans, LA, 70118, USA; University of Texas at Dallas, Department of Bioengineering, 800 W. Campbell Road, Richardson, TX, 75080, USA.
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Snyder W, McGuire JA, Mou C, Dillard DA, Iliescu T, De Vita R. Data-driven variational multiscale reduced order modeling of vaginal tissue inflation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3660. [PMID: 36333869 DOI: 10.1002/cnm.3660] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/04/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
The vagina undergoes large finite deformations and has complex geometry and microstructure, resulting in material and geometric nonlinearities, complicated boundary conditions, and nonhomogeneities within finite element (FE) simulations. These nonlinearities pose a significant challenge for numerical solvers, increasing the computational time by several orders of magnitude. Simplifying assumptions can reduce the computational time significantly, but this usually comes at the expense of simulation accuracy. This study proposed the use of reduced order modeling (ROM) techniques to capture experimentally measured displacement fields of rat vaginal tissue during inflation testing in order to attain both the accuracy of higher-fidelity models and the speed of simpler simulations. The proper orthogonal decomposition (POD) method was used to extract the significant information from FE simulations generated by varying the luminal pressure and the parameters that introduce the anisotropy in the selected constitutive model. A new data-driven (DD) variational multiscale (VMS) ROM framework was extended to obtain the displacement fields of rat vaginal tissue under pressure. For comparison purposes, we also investigated the classical Galerkin ROM (G-ROM). In our numerical study, both the G-ROM and the DD-VMS-ROM decreased the FE computational cost by orders of magnitude without a significant decrease in numerical accuracy. Furthermore, the DD-VMS-ROM improved the G-ROM accuracy at a modest computational overhead. Our numerical investigation showed that ROM has the potential to provide efficient and accurate computational tools to describe vaginal deformations, with the ultimate goal of improving maternal health.
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Affiliation(s)
- William Snyder
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA
| | - Jeffrey A McGuire
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA
| | - Changhong Mou
- Department of Mathematics, Virginia Tech, Blacksburg, Virginia, USA
| | - David A Dillard
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA
| | - Traian Iliescu
- Department of Mathematics, Virginia Tech, Blacksburg, Virginia, USA
| | - Raffaella De Vita
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA
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Dubik J, Tartaglione A, Miller KS, Dillard DA, De Vita R. History-Dependent Deformations of Rat Vaginas under Inflation. Integr Comp Biol 2022; 62:icac110. [PMID: 35781491 DOI: 10.1093/icb/icac110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The vagina is a highly inhomogeneous, anisotropic, and viscoelastic organ that undergoes significant deformations in vivo. The mechanical attributes of this organ facilitate important physiological functions during menstruation, intercourse, and birthing. Despite the crucial mechanical role that the vagina plays within the female reproductive system, the deformations that the organ can sustain over time under constant pressure, in both the longitudinal direction (LD) and circumferential direction (CD), have not been fully characterized. This experimental study focuses on quantifying the creep properties of the vagina via ex vivo inflation testing using the rat as animal model. Toward this end, rat vaginas were subjected to three consecutively increasing constant luminal pressures (28 kPa, 55 kPa, and 83 kPa) using a custom-built experimental setup and the resulting inhomogeneous deformations were measured using the digital image correlation (DIC) method. The vagina was found to deform significantly more in the CD than the LD at any constant pressure, suggesting that the organ primarily adapts to constant pressures by significantly changing the diameter rather that the length. The change in deformation over time (i.e., creep) was significantly higher during the 1st inflation test at a constant pressure of 28 kPa than over the 2nd and 3rd inflation tests at constant pressures of 55 kPa and 83 kPa, respectively. The findings of this study on the mechanical behavior of the vagina could serve to advance our limited knowledge about the physiology and pathophysiology of this important reproductive organ.
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Affiliation(s)
- Justin Dubik
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
| | - Alfonsina Tartaglione
- Department of Mathematics and Physics, Università degli Studi della Campania "Luigi Vanvitelli", Viale Abramo Lincoln 5, Caserta, 81100, CE, Italy
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University, 531 Lindy Boggs, New Orleans, 70118, LA, USA
| | - David A Dillard
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 219A Norris Hall, 495 Old Turner Street, Blacksburg, 24061, VA, USA
| | - Raffaella De Vita
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
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