The challenge of stress incontinence and pelvic organ prolapse: revisiting biologic mesh materials

Changes in the Level of hs-CRP in the Blood and Morphometric Parameters of Tissues Following Implantation of Polypropylene

In recent decades, the use of polypropylene meshes has been the gold standard in the surgical treatment of muscular corset failure. However, the reasons behind the low percentage of complications and recurrences remain controversial. Tissue hyperreactivity and the immune response to polypropylene may be contributing factors. Measurements of the level of hs-CRP (highly sensitive C-reactive protein) in the blood and morphometric studies of tissues around the implant were carried out for three months after the installation of polypropylene implants in 53 laboratory rats. The research results confirmed the good biocompatibility of polypropylene and the formation of full-fledged connective tissue around polypropylene three months after the installation of the material. The level of hs-CRP in the blood increased slightly, without significant differences, but in some animals, there was a sharp increase in this indicator at 3 months. Such results may indicate the development of hyperreactivity to the implantation of a synthetic material and, with other accompanying factors, lead to the development of complications both at the local tissue and general immune levels.

Anterior Colporrhaphy and Paravaginal Repair for Anterior Compartment Prolapse: A Review

Pelvic organ prolapse, particularly in the anterior compartment, is a prevalent condition that significantly impacts women's quality of life. Two common surgical approaches for managing anterior vaginal wall prolapse are anterior colporrhaphy and paravaginal repair. Anterior colporrhaphy, a traditional technique, involves the plication of weakened fascial tissues to restore support to the bladder and anterior vaginal wall. Paravaginal repair addresses lateral detachment of the anterior vaginal wall by reattaching it to its supportive structures. This review aimed to compare the indications, techniques, and outcomes between these surgical methods, discussing their efficacy, recurrence rates, and complications. Although anterior colporrhaphy is widely used, paravaginal repair may offer superior results in specific cases, particularly those involving lateral defects. The review also explored the evolution of these techniques, the role of grafts and mesh, and the potential benefits of minimally invasive approaches such as laparoscopy and robotic surgery. The goal is to provide clinicians with comprehensive insights into choosing the appropriate surgical option based on individual patient anatomy and clinical presentation, thus optimizing outcomes and minimizing recurrence.

Promoting cell proliferation and collagen production with ascorbic acid 2-phosphate-releasing poly(l-lactide-co-ε-caprolactone) membranes for treating pelvic organ prolapse

Pelvic organ prolapse (POP) afflicts millions of women globally. In POP, the weakened support of the pelvic floor results in the descent of pelvic organs into the vagina, causing a feeling of bulging, problems in urination, defaecation and/or sexual function. However, the existing surgical repair methods for relapsed POP remain insufficient, highlighting the urgent need for more effective alternatives. Collagen is an essential component in pelvic floor tissues, providing structural support, and its production is controlled by ascorbic acid. Therefore, we investigated novel ascorbic acid 2-phosphate (A2P)-releasing poly(l-lactide-co-ε-caprolactone) (PLCLA2P) membranes in vitro to promote cell proliferation and extracellular matrix protein production to strengthen the natural support of the pelvic fascia for POP applications. We analysed the mechanical properties and the impact of PLCLA2P on cellular responses through cell culture analysis using human vaginal fibroblasts (hVFs) and human adipose-derived stem/stromal cells (hASCs) compared to PLCL. In addition, the A2P release from PLCLA2P membranes was assessed in vitro. The PLCLA2P demonstrated slightly lower tensile strength (2.2 ± 0.4 MPa) compared to PLCL (3.7 ± 0.6 MPa) for the first 4 weeks in vitro. The A2P was most rapidly released during the first 48 h of in vitro incubation. Our findings demonstrated significantly increased proliferation and collagen production of both hVFs and hASCs on A2P-releasing PLCLA2P compared to PLCL. In addition, extracellular collagen Type I fibres were detected in hVFs, suggesting enhanced collagen maturation on PLCLA2P. Moreover, increased extracellular matrix protein expression was detected on PLCLA2P in both hVFs and hASCs compared to plain PLCL. In conclusion, these findings highlight the potential of PLCLA2P as a promising candidate for promoting tissue regeneration in applications aimed for POP tissue engineering applications.

Age-Related Changes in Urethral Structure and Responds to Injury: Single-Cell Atlas of a Rat Model of Vaginal Birth Injury induced Stress Urinary Incontinence

Stress urinary incontinence (SUI) greatly affects the daily life of numerous women and is closely related to a history of vaginal delivery and aging. We used vaginal balloon dilation to simulate vaginal birth injury in young and middle-aged rats to produce a SUI animal model, and found that young rats restored urethral structure and function well, but not the middle-aged rats. To identify the characteristics of cellular and molecular changes in the urethral microenvironment during the repair process of SUI. We profiled 51,690 individual female rat urethra cells from 24 and 48 weeks old, with or without simulated vaginal birth injury. Cell interaction analysis showed that signal networks during repair process changed from resting to active, and aging altered the distribution but not the overall level of cell interaction in the repair process. Similarity analysis showed that muscle, fibroblasts, and immune cells underwent large transcriptional changes during aging and repair. In middle-aged rats, cell senescence occurs mainly in the superficial and middle urothelium due to cellular death and shedding, and the basal urothelium expressed many Senescence-Associated Secretory Phenotype (SASP) genes. In conclusion, we established the aging and vaginal balloon dilation (VBD) model of female urethral cell anatomy and the signal network landscape, which provides an insight into the normal or disordered urethra repair process and the scientific basis for developing novel SUI therapies.

Knowledge mapping and visualization analysis of pelvic organ prolapse repair with mesh from 2001 to 2021

Aims: In recent decades, extensive attention has been paid to the application of mesh to repair pelvic floor defects. However, a large body of related literature has not been system summarized. The purpose of this study is to summarize and visualize the literature on pelvic organ prolapse (POP) repair with mesh using bibliometrics. Methods: Medical literature regarding POP repair with mesh were searched and obtained in the Web of Science™ Core (WoSCC) database from 2001 to 2021. Microsoft Excel 2020, CiteSpace and VOSviewer were used to conduct the bibliometric and knowledge-map analysis. Results: In the past 20 years, a total of 2,550 articles and reviews have been published in 35 journals, and the published and cited results show a growing trend. Cosson M and International Urogynecology Journal were the authors and journals with the highest output, respectively. The United States, France and the United Kingdom are among the top three countries/organizations in relevant publications in worldwide. 584 key words in the literature are divided into 8 clusters, which are mainly related to prolapse type, risk factors, surgical methods, imaging, quality of life and bioengineering. Using clinical research and tissue engineering technology to reduce mesh complications is the current hot spot in this field. Conclusion: Reasonable application of mesh and avoiding mesh complications are still the most concerned topics in POP research. Although clinical research, surgical improvement, biological mesh and bioengineering technology have shown promising results, it is still urgent to carry out clinical transformation application research.

Enhanced Myogenesis by Silencing Myostatin with Nonviral Delivery of dCas9 Ribonucleoprotein Complex

Stress urinary incontinence (SUI) and pelvic floor disorder (PFD) are common conditions with limited treatment options in women worldwide. Regenerative therapy to restore urethral striated and pelvic floor muscles represents a valuable therapeutic approach. We aim to determine the CRISPR interference-mediated gene silencing effect of the nonviral delivery of nuclease-deactivated dCas9 ribonucleoprotein (RNP) complex on muscle regeneration at the cellular and molecular level. We designed four myostatin (MSTN)-targeting sgRNAs and transfected them into rat myoblast L6 cells together with the dCas9 protein. Myogenesis assay and immunofluorescence staining were performed to evaluate muscle differentiation, while CCK8 assay, cell cycle assay, and 5-ethynyl-2'-deoxyuridine staining were used to measure muscle proliferation. Reverse transcription-polymerase chain reaction and Western blotting were also performed to examine cellular signaling. Myogenic factors (including myosin heavy chain, MSTN, myocardin, and serum response factor) increased significantly after day 5 during myogenesis. MSTN was efficiently silenced after transfecting the dCas9 RNP complex, which significantly promoted more myotube formation and a higher fusion index for L6 cells. In cellular signaling, MSTN repression enhanced the expression of MyoG and MyoD, phosphorylation of Smad2, and the activity of Wnt1/GSK-3β/β-catenin pathway. Moreover, MSTN repression accelerated L6 cell growth with a higher cell proliferation index as well as a higher expression of cyclin D1 and cyclin E. Nonviral delivery of the dCas9 RNP complex significantly promoted myoblast differentiation and proliferation, providing a promising approach to improve muscle regeneration for SUI and PFD. Further characterization and validation of this approach in vivo are needed.

Exploratory safety study of an umbilical cord derived urethral sling in bilateral pudendal nerves injury-induced urinary incontinence in female rats

PURPOSE

Mid-urethral slings are the standard treatment for women with refractory stress urinary incontinence (SUI) but are at risk of infection or erosion due to host-prothesis interaction. In this proof-of-concept study, we aimed at evaluating umbilical vessel sling (UVS) in incontinent female rats.

MATERIAL AND METHODS

UVS was extracted from human umbilical cord lining and was placed on female rats who underwent bilateral pelvic nerve injury (PNI) to reproduce SUI (Group 3, N = 10). Two control groups were also studied: rats with no PNI (Group 1, N = 4) and rats with PNI but no UVS (Group 2, N = 10). Micturition calendar was frequently recorded using a metabolic cage, and leak point pressure (LPP) test was performed on Day 28. After the LPP test, rats were euthanized, and bladder/urethra were collected for histopathological analysis.

RESULTS

Overall, 24 rats were included, of whom 10 had both PNI and UVS placement. Compared with Group 2, Group 3 had increased maximal LPP but the difference did not reach significance (respectively 21.8 ± 2.1 mmHg vs. 28.4 ± 4.1 mmHg, p = 0.2). Micturition frequencies were similar between the groups. Total voided volume was higher in Group 3 at the end of the study compared with Group 2 (12.5 ± 1.1 ml vs. 9.4 ± 0.6 ml, respectively, p < 0.05). Histopathological findings evidenced a good local tolerance and a moderate to high tissue integration of the UVS.

CONCLUSIONS

Biological sling derived from human umbilical vessel could be safely placed with a slight improvement of LPP in a population of rats who had bilateral PNI without major modification of micturition calendar. UVS could be a promising biomaterial in the management of SUI in women. Clinical studies are needed.

Transcriptome-targeted analysis of human peripheral blood-derived macrophages when cultured on biomaterial meshes

Surgical meshes are commonly used to repair defects and support soft tissues. Macrophages (Mφs) are critical cells in the wound healing process and are involved in the host response upon foreign biomaterials. There are various commercially available permanent and absorbable meshes used by surgeons for surgical interventions. Polypropylene (PP) meshes represent a permanent biomaterial that can elicit both inflammatory and anti-inflammatory responses. In contrast, poly-4-hydroxybutyrate (P4HB) based meshes are absorbable and linked to positive clinical outcomes but have a poorly characterized immune response. This study evaluated the in vitro targeted transcriptomic response of human Mφs seeded for 48 h on PP and P4HB surgical meshes. The in vitro measured response from human Mφs cultured on P4HB exhibited inflammatory and anti-inflammatory gene expression profiles typically associated with wound healing, which aligns with in vivo animal studies from literature. The work herein provides in vitro evidence for the early transcriptomic targeted signature of human Mφs upon two commonly used surgical meshes. The findings suggest a transition from an inflammatory to a non-inflammatory phenotype by P4HB as well as an upregulation of genes annotated under the pathogen response pathway.

A novel antibacterial biomaterial mesh coated by chitosan and tigecycline for pelvic floor repair and its biological performance

The biomaterials composed of mammalian extracellular matrix (ECM) have a great potential in pelvic floor tissue repair and functional reconstruction. However, bacterial infection does cause great damage to the repair function of biomaterials which is the major problem in clinical utilization. Therefore, the development of biological materials with antimicrobial effect is of great clinical significance for pelvic floor repair. Chitosan/tigecycline (CS/TGC) antibacterial biofilm was prepared by coating CS/TGC nanoparticles on mammalian-derived ECM. Infrared spectroscopy, scanning electron microscopy, bacteriostasis circle assay and static dialysis methods were used to characterize the membrane. MTS assay kit and DAPI fluorescence staining were used to evaluate cytotoxicity and cell adhesion. The biocompatibility was assessed by subabdominal implantation model in goats. Subcutaneous antimicrobial test in rabbit back was used to evaluate the antimicrobial and repairing effects on the infected wounds in vivo. Infrared spectroscopy showed that the composite coating had been successfully modified. The antibacterial membrane retained the main structure of ECM multilayer fibers. In vitro release of biomaterials showed sustained release and stability. In vivo studies showed that the antibacterial biological membrane had low cytotoxicity, fast degradation, good compatibility, anti-infection and excellent repair ability.

Delayed Treatment With Low-intensity Extracorporeal Shock Wave Therapy in an Irreversible Rat Model of Stress Urinary Incontinence

OBJECTIVE

To determine the outcomes and mechanisms of delayed low-intensity extracorporeal shock wave therapy (Li-ESWT) in a rat model of irreversible stress urinary incontinence (SUI).

MATERIALS AND METHODS

Twenty-four female Sprague-Dawley rats were randomly assigned into 3 groups: sham control, vaginal balloon dilation + β-aminopropionitrile (BAPN; SUI group), and vaginal balloon dilation + BAPN + treatment with Li-ESWT (SUI-Li-ESWT group). An irreversible SUI model was developed by inhibiting the urethral structural recovery with BAPN daily for 5 weeks. Thereafter, in the SUI-Li-ESWT group, Li-ESWT was administered twice per week for 2 weeks. After a 1-week washout, all 24 rats were evaluated with functional and histologic studies at 17 weeks of age. Endogenous progenitor cells were detected via the EdU-labeling method.

RESULTS

Functional analysis with leak point pressure testing showed that the SUI-Li-ESWT group had significantly higher leak point pressures compared with untreated rats. Increased urethral and vaginal smooth and striated muscle content and increased thickness of the vaginal wall were noted in the SUI-Li-ESWT group. The SUI group had significantly decreased neuronal nitric oxide /tyrosine hydroxylase positive nerves ratio in the smooth muscle layers of the urethra, while the SUI-Li-ESWT group had neuronal nitric oxide/tyrosine hydroxylase+ nerves ratio similar to that of the control group. The continuality of urothelial cell lining was also improved in the SUI-Li-ESWT group. In addition, there were significantly increased EdU-positive cells in the SUI-Li-ESWT group.

CONCLUSION

Li-ESWT appears to increase smooth muscle content in the urethra and the vagina, increase the thickness of urethral wall, improve striated muscle content and neuromuscular junctions, restore the integrity of the urothelium, and increase the number of EdU-retaining progenitor cells in the urethral wall.