Evidence of time dependent degradation of polypropylene surgical mesh explanted from the abdomen and vagina of sheep.

The failure of polypropylene mesh is marked by significant side effects and debilitation, arising from a complex interplay of factors. One key contributor is the pronounced physico-mechanical mismatch between the polypropylene (PP) fibres and surrounding tissues, resulting in substantial physical damage, inflammation, and persistent pain. However, the primary cause of sustained inflammation due to polypropylene itself remains incompletely understood.

VEGF overexpressed mesoangioblasts enhance urethral and vaginal recovery following simulated vaginal birth in rats.

Vaginal birth causes pelvic floor injury which may lead to urinary incontinence. Cell therapy has been proposed to assist in functional recovery. We aim to assess if intra-arterial injection of rat mesoangioblasts (MABs) and stable Vascular Endothelial Growth Factor (VEGF)-expressing MABs, improve recovery of urethral and vaginal function following simulated vaginal delivery (SVD).

Effects of cumulative duration of repeated anaesthesia exposure on foetal brain development in the ovine model.

Objective: Anaesthesia is required in 0.4-1% of pregnant women, and prolonged and repeated exposures to anaesthesia may be required. It is unknown whether these exposures may result in foetal neurotoxicity in humans.

Evaluation of the short-term host response and biomechanics of an absorbable poly-4-hydroxybutyrate scaffold in a sheep model following vaginal implantation.

Objective: To evaluate the host- and biomechanical response to a fully absorbable poly-4-hydroxybutyrate (P4HB) scaffold in comparison with the response to polypropylene (PP) mesh.

Design: In vivo animal experiment.

Setting: KU Leuven Center for Surgical Technologies.

Animal models for pelvic organ prolapse: systematic review.

Introduction And Hypothesis: We aimed to summarize the knowledge on the pathogenesis of pelvic organ prolapse (POP) generated in animal models.

Methods: We searched MEDLINE, Embase, Cochrane and the Web of Science to establish what animal models are used in the study of suggested risk factors for the development of POP, including pregnancy, labor, delivery, parity, aging and menopause. Lack of methodologic uniformity precluded meta-analysis; hence, results are presented as a narrative review.

The ewe as an animal model of vaginal atrophy and vaginal Er:YAG laser application.

Objective: In sheep of reproductive age, we aimed to document decrease in epithelial thickness, glycogen amount, and other vaginal changes after castration and the effect of Er:YAG laser as used clinically.

Methods: On day 0, 16 sheep underwent ovariectomy. They were randomized to sham or three vaginal Er:YAG laser applications at monthly intervals.

Effects of non-ablative Er:YAG laser on the skin and the vaginal wall: systematic review of the clinical and experimental literature.

Introduction And Hypothesis: Er:YAG laser is frequently used in dermatology and gynecology. Clinical studies document high satisfaction rates; however, hard data on the effects at the structural and molecular levels are limited. The aim of this systematic review was to summarize current knowledge about the objective effects of non-ablative Er:YAG laser on the skin and vaginal wall.

Functional evaluation of prevascularization in one-stage versus two-stage tissue engineering approach of human bio-artificial muscle.

A common shortcoming of current tissue engineered constructs is the lack of a functional vasculature, limiting their size and functionality. Prevascularization is a possible strategy to introduce vascular networks in these constructs. It includes among others co-culturing target cells with endothelial (precursor) cells that are able to form endothelial networks through vasculogenesis.

Functional supramolecular bioactivated electrospun mesh improves tissue ingrowth in experimental abdominal wall reconstruction in rats.

Development of biomaterials for hernia and pelvic organ prolapse (POP) repair is encouraged because of high local complication rates with current materials. Therefore, we aimed to develop a functionalized electrospun mesh that promotes tissue ingrowth and provides adequate mechanical strength and compliance during degradation. We describe the in vivo function of a new supramolecular bioactivated polycarbonate (PC) material based on fourfold hydrogen bonding ureidopyrimidinone (UPy) units (UPy-PC).

Predicting the mechanical response of the vaginal wall in ball burst tests based on histology.

A histologically motivated (HM) coefficient that establishes a link between tissue's microstructure and material model through histological data is used in the prediction of the mechanical properties of vaginal tissue that is subjected to multiaxial loading conditions. Therefore, the material parameters were based on an HM coefficient obtained from tensile testing and histological data of comparable tissues. Uniaxial tensile test data and histological data were collected from three groups of sheep at different time points in their life cycle, including virgins, pregnant, and parous ewes.

The histological microstructure and in vitro mechanical properties of pregnant and postmenopausal ewe perineal body.

Objective: The mechanical properties and microstructure of the perineal body are important for the improvement of numerical models of pelvic organs. We determined the mechanical parameters and volume fractions of the ewe perineal body as an animal model.

Methods: The 39 specimens of 13 pregnant swifter ewes delivering by cesarean section (aged 2 years, weight 61.

The importance of developing relevant animal models to assess existing and new materials.

Purpose Of Review: We summarize the recent literature on the use of different animal models for testing existing and new materials for treatment of pelvic organ prolapse.

Recent Findings: A wide spectrum of animal models is being used in urogynecology, both for the study of physiologic and pathophysiologic processes, training in surgical procedures, yet mainly to study the host response to implant materials. The quality of studies is variable, and procedures, read-outs, and reporting are not standardized.

Morphological and Functional Changes in the Vagina following Critical Lifespan Events in the Ewe.

Background/aims: The ewe is increasingly being used as an animal model for pelvic floor disorders. The aim was to further characterize changes in the vaginal properties during its entire lifespan.

Methods: Vaginal tissues were collected at different stages of reproductive life (neonatal, prepubescence, nulliparous, primiparous, multiparous, and menopausal; ≥6 ewes/group).

The effect of consecutive pregnancies on the ovine pelvic soft tissues: Link between biomechanical and histological components.

Background: Pelvic organ prolapse, various types of incontinence (urinary incontinence, defecatory dysfunction), chronic cystourethritis, and sexual dysfunctions remain between the most common disorders in urogynecology. Currently, it is believed that the nature and number of births plays a major role in their development. Moreover, after these events, pelvic floor tissues may not recover to their original statuses.

Linking hyperelastic theoretical models and experimental data of vaginal tissue through histological data.

Mechanical characterization of living tissues and computer-based simulations related to medical issues, has become increasingly important to improve diagnostic processes and treatments evaluation. This work proposes a link between the mechanical testing and the material model predictions through histological data of vaginal tissue. Histological data was used to link tensile testing experiments with material-dependent parameters; the approach was adequate to capture the nonlinear response of ovine vaginal tissue over a large strain range.

Experimental reconstruction of an abdominal wall defect with electrospun polycaprolactone-ureidopyrimidinone mesh conserves compliance yet may have insufficient strength.

Purpose: Electrospun meshes mimic the extracellular matrix, which may improve their integration. We aimed to compare polycaprolactone (PCL) modified with ureidopyrimidinone (UPy) electrospun meshes with ultra-lightweight polypropylene (PP; Restorelle) reference textile meshes for in vivo compliance. We chose UPy-PCL because we have shown it does not compromise biomechanical properties of native tissue, and because it potentially can be bioactivated.

Assessment of Electrospun and Ultra-lightweight Polypropylene Meshes in the Sheep Model for Vaginal Surgery.

Background: There is an urgent need to develop better materials to provide anatomical support to the pelvic floor without compromising its function.

Objective: Our aim was to assess outcomes after simulated vaginal prolapse repair in a sheep model using three different materials: (1) ultra-lightweight polypropylene (PP) non-degradable textile (Restorelle) mesh, (2) electrospun biodegradable ureidopyrimidinone-polycarbonate (UPy-PC), and (3) electrospun non-degradable polyurethane (PU) mesh in comparison with simulated native tissue repair (NTR). These implants may reduce implant-related complications and avoid vaginal function loss.

Fate of mesoangioblasts in a vaginal birth injury model: influence of the route of administration.

Currently cell therapy is considered as an experimental strategy to assist the healing process following simulated vaginal birth injury in rats, boosting the functional and morphologic recovery of pelvic floor muscles and nerves. However, the optimal administration route and dose still need to be determined. Mesangioblasts theoretically have the advantage that they can differentiate in skeletal and smooth muscle.

Retrieval and registration of long-range overlapping frames for scalable mosaicking of in vivo fetoscopy.

Purpose: The standard clinical treatment of Twin-to-Twin transfusion syndrome consists in the photo-coagulation of undesired anastomoses located on the placenta which are responsible to a blood transfer between the two twins. While being the standard of care procedure, fetoscopy suffers from a limited field-of-view of the placenta resulting in missed anastomoses. To facilitate the task of the clinician, building a global map of the placenta providing a larger overview of the vascular network is highly desired.

Short term post-operative morphing of sacrocolpopexy mesh measured by magnetic resonance imaging.

Background: Sacrocolpopexy (SC) involves suspension of the vaginal vault or cervix to the sacrum using a mesh. Following insertion, the meshes have been observed to have undergone dimensional changes.

Objective: To quantify dimensional changes of meshes following implantation and characterize their morphology in-vivo.

First delivery and ovariectomy affect biomechanical and structural properties of the vagina in the ovine model.

Introduction And Hypothesis: Animal models are useful for investigating the genesis of pelvic floor dysfunction and for developing novel therapies for its treatment. There is a need for an alternative large-animal model to the nonhuman primate. Therefore we studied the effects of the first vaginal delivery, ovariectomy and systemic hormonal replacement therapy (HRT) on the biomechanical and structural properties of the ovine vagina.

In vivo documentation of shape and position changes of MRI-visible mesh placed in rectovaginal septum.

Background And Objective: Large deformations in synthetic meshes used in pelvic organ prolapse surgery may lead to suboptimal support for the underlying tissue, graft-related complications as well as recurrence. Our aim was to quantify in vivo longitudinal changes in mesh shape and geometry in a large animal model. We compare two commonly used mesh shapes, armed and flat, that are differently affixed.

Physiologic musculofascial compliance following reinforcement with electrospun polycaprolactone-ureidopyrimidinone mesh in a rat model.

Purpose: Electrospun meshes may be considered as substitutes to textile polypropylene implants. We compared the host response and biomechanical properties of the rat abdominal wall following reinforcement with either polycaprolactone (PCL) modified with ureidopyrimidinone-motifs (UPy) or polypropylene mesh.

Methods: First we measured the response to cyclic uniaxial load within the physiological range both dry (room temperature) and wet (body temperature).

Biomechanical and morphological properties of the multiparous ovine vagina and effect of subsequent pregnancy.

Pelvic floor soft tissues undergo changes during the pregnancy. However, the degree and nature of this process is not completely characterized. This study investigates the effect of subsequent pregnancy on biomechanical and structural properties of ovine vagina.

Comparative Anatomy of the Ovine and Female Pelvis.

Background: Pelvic organ prolapse affects half of vaginally parous women. Several animal models are used to study its pathophysiology and treatment. Sheep are interesting because they develop spontaneously prolapse with similar risk factors as women and can be used for vaginal surgery.