Demonstration of improved tissue integration and angiogenesis with an elastic, estradiol releasing polyurethane material designed for use in pelvic floor repair

Evaluation of Electrospun Poly-4-Hydroxybutyrate as Biofunctional and Degradable Scaffold for Pelvic Organ Prolapse in a Vaginal Sheep Model

Pelvic organ prolapse (POP) affects many women, especially after menopause. POP occurs due to the descent of weakened supportive tissue. Current prolapse surgeries have high failure rates, due to disturbed wound healing caused by lower tissue regeneration and estrogen depletion. Absorbable poly-4-hydroxybutyrate (P4HB) knit implants exhibited improved cell and tissue response leading to less complications from prolapse surgery. This study aims to enhance wound healing and improve surgical outcomes by using an electrospun (ES) P4HB scaffold (ES P4HB) that emulates natural tissue structure. Further 17β-estradiol (E2)-a prominent wound healing factor-is incorporated into the scaffold (ES P4HB-E2). Parous Dohne Merino sheep underwent posterior vaginal wall implantation of either P4HB (n = 6) or 17β-estradiol relasing P4HB-E2 (n = 6) scaffolds, or underwent native tissue repair (NTR) (n = 4). Vaginal explants were compared for short-term host response in terms of gross necropsy, histomorphology, biomechanics, tissue-integration, and degradation of P4HB at 3-months post-implantation. Both scaffolds show promising results with enhanced mechanical properties and increased macrophage infiltration compared to NTR, but without differences between scaffolds. Thus, it seems electrospun P4HB scaffolds already improve tissue integration and healing. Further long-term studies are needed before these scaffolds can be used in clinical practice.

Design and development of vaginal wall mimicking poly(ϵ-caprolactone) based nanofibrous prosthetic mesh for pelvic organ prolapse: evaluation of biocompatibility and antibacterial ability

Mechanical non-conformance of conventionally used transvaginal non-degradable meshes has led to complications such as organ perforation, dyspareunia caused by mesh stiffness and stress shielding. In this study, we have solved the dire need to mimic the mechanical properties of the vaginal wall by designing and developing a soft and elastic mesh made of polycaprolactone (PCL), citric acid modified polyethylene glycol (PEGC) and zinc oxide (ZnO) prepared through electrospinning and testedin vitroandin vivo. The mesh containing 90:10:0.1 of PCL, PEGC and ZnO (PEGC-15 0.1ZnO mesh) conforms to the mechanical properties of the vaginal wall of the pelvic floor, has a burst strength of ∼35 N even after gamma-sterilization and 28 d of degradation inin vitro.In vitrostudies using adipose-derived stem cells revealed that the PCL-PEGC-15 0.1ZnO meshes were biocompatible and supported higher collagen production than commercial mesh.An in vitrobacterial adhesion study showed a 2-log reduction compared to commercially available mesh for prolapse treatment. Initial biocompatibility assessment in a rabbit model also showed that the PCL-PEGC-15 0.1ZnO mesh is biocompatible and supports fibrosis throughout the mesh. The softness and flexibility of the PCL-PEGC-15 0.1ZnO mesh based onin vitrotrials and initialin vivotrials show that the mesh has a potential clinical impact for pelvic floor repair treatment.

Polyurethane infused with heparin capped silver nanoparticles dressing for wound healing application: Synthesis, characterization and antimicrobial studies

Burn and diabetic wounds present significant challenges due to their complex nature, delayed healing, pain, and high susceptibility to bacterial infections. In this study, we developed and evaluated polyurethane (PU) nanofibers embedded with heparin-functionalized silver nanoparticles (hep-AgNPs) using an electrospinning technique. The choice to functionalize silver nanoparticles with heparin was based on heparin's established role in modulating inflammation and promoting angiogenesis. The electrospun nanofibers exhibited smooth, bead-free morphology with diameters ranging from 300 to 500 nm and demonstrated a sustained release of silver over seven days, offering continuous antimicrobial protection. Mechanical testing of the nanofibers revealed excellent strength and elasticity, making them well-suited for flexible wound dressings. The nanofibers also showed superior water absorption, fluid retention, and controlled water vapor transmission, essential for maintaining a moist wound environment conducive to healing. In vitro biocompatibility assays confirmed that the PU/hep-AgNPs bandages were non-toxic to keratinocytes and fibroblasts and significantly accelerated wound closure, as evidenced by scratch assays. The nanofibrous bandages also exhibited potent antibacterial activity against Staphylococcus aureus and Salmonella Typhimurium, two common wound pathogens. Overall, our findings demonstrate that PU/hep-AgNPs nanofibrous bandages are a promising candidate for chronic wound healing. They combine excellent biocompatibility, anti-inflammatory properties, and strong antimicrobial activity, which collectively contribute to faster wound healing and reduced risk of infection.

Mechanoresponsive Drug Release from a Flexible, Tissue-Adherent, Hybrid Hydrogel Actuator

Soft robotic technologies for therapeutic biomedical applications require conformal and atraumatic tissue coupling that is amenable to dynamic loading for effective drug delivery or tissue stimulation. This intimate and sustained contact offers vast therapeutic opportunities for localized drug release. Herein, a new class of hybrid hydrogel actuator (HHA) that facilitates enhanced drug delivery is introduced. The multi-material soft actuator can elicit a tunable mechanoresponsive release of charged drug from its alginate/acrylamide hydrogel layer with temporal control. Dosing control parameters include actuation magnitude, frequency, and duration. The actuator can safely adhere to tissue via a flexible, drug-permeable adhesive bond that can withstand dynamic device actuation. Conformal adhesion of the hybrid hydrogel actuator to tissue leads to improved mechanoresponsive spatial delivery of the drug. Future integration of this hybrid hydrogel actuator with other soft robotic assistive technologies can enable a synergistic, multi-pronged treatment approach for the treatment of disease.

Chorioallantoic Membrane Assay at the Cross-Roads of Adipose-Tissue-Derived Stem Cell Research

With a history of more than 100 years of different applications in various scientific fields, the chicken chorioallantoic membrane (CAM) assay has proven itself to be an exceptional scientific model that meets the requirements of the replacement, reduction, and refinement principle (3R principle). As one of three extraembryonic avian membranes, the CAM is responsible for fetal respiration, metabolism, and protection. The model provides a unique constellation of immunological, vascular, and extracellular properties while being affordable and reliable at the same time. It can be utilized for research purposes in cancer biology, angiogenesis, virology, and toxicology and has recently been used for biochemistry, pharmaceutical research, and stem cell biology. Stem cells and, in particular, mesenchymal stem cells derived from adipose tissue (ADSCs) are emerging subjects for novel therapeutic strategies in the fields of tissue regeneration and personalized medicine. Because of their easy accessibility, differentiation profile, immunomodulatory properties, and cytokine repertoire, ADSCs have already been established for different preclinical applications in the files mentioned above. In this review, we aim to highlight and identify some of the cross-sections for the potential utilization of the CAM model for ADSC studies with a focus on wound healing and tissue engineering, as well as oncological research, e.g., sarcomas. Hereby, the focus lies on the combination of existing evidence and experience of such intersections with a potential utilization of the CAM model for further research on ADSCs.

Absorbable Electrospun Poly-4-hydroxybutyrate Scaffolds as a Potential Solution for Pelvic Organ Prolapse Surgery

Women with pelvic organ prolapse (POP) have bothersome complaints that significantly affect their quality of life. While native tissue repair is associated with high recurrence rates, polypropylene knitted implants have caused specific implant-related adverse events that have detrimental, often irreversible, effects. We hypothesize that surgical outcome can be improved with a tissue-engineered solution using an absorbable implant that mimics the natural extracellular matrix (ECM) structure, releases estrogen, and activates collagen metabolism by fibroblasts as the main regulators of wound healing. To this aim, we produced electrospun poly-4-hydroxybutyrate (P4HB) scaffolds and biofunctionalized them with estradiol (E2). The cell-implant interactions relevant for POP repair were assessed by seeding primary POP vaginal fibroblasts isolated from patients on electrospun P4HB scaffolds with 1%, 2%, or 5% E2 and without E2. To test our hypothesis on whether ECM mimicking structures should improve regeneration, electrospun P4HB was compared to knitted P4HB implants. We evaluated vaginal fibroblast proliferation, ECM deposition, and metabolism by quantification of collagen, elastin, and matrix metalloproteinases and by gene expression analysis for 28 days. We established effective E2 drug loading with a steady release over time. Significantly higher cell proliferation, collagen-, and elastin deposition were observed on electrospun P4HB scaffolds as compared to knitted P4HB. For this study, physical properties of the scaffolds were more determinant on the cell response than the release of E2. These results indicate that making these electrospun P4HB scaffolds E2-releasing appears to be technically feasible. In addition, electrospun P4HB scaffolds promote the cellular response of vaginal fibroblasts and further studies are merited to assess if their use results in improved surgical outcomes in case of POP repair.

Tissue-engineered repair material for pelvic floor dysfunction

Pelvic floor dysfunction (PFD) is a highly prevalent urogynecology disorder affecting many women worldwide, with symptoms including pelvic organ prolapse (POP), stress urinary incontinence (SUI), fecal incontinence, and overactive bladder syndrome (OAB). At present, the clinical treatments of PFD are still conservative and symptom-based, including non-surgical treatment and surgery. Surgical repair is an effective and durable treatment for PFD, and synthetic and biological materials can be used to enforce or reinforce the diseased tissue. However, synthetic materials such as polypropylene patches caused a series of complications such as mesh erosion, exposure, pain, and inflammation. The poor mechanical properties and high degradation speed of the biomaterial meshes resulted in poor anatomical reduction effect and limitation to clinical application. Therefore, the current treatment options are suboptimal. Recently, tissue-engineered repair material (TERM) has been applied to repair PFD and could markedly improve the prognosis of POP and SUI repair surgery in animal models. We review the directions and progression of TERM in POP and SUI repair. Adipose-derived stem cells (ADSCs) and endometrial mesenchymal stem cells (eMSCs) appear to be suitable cell types for scaffold seeding and clinical implantation. The multidisciplinary therapy approach to tissue engineering is a promising direction for tissue repair. More and longer follow-up studies are needed before determining cell types and materials for PFD repair.

VEGF-A and FGF4 Engineered C2C12 Myoblasts and Angiogenesis in the Chick Chorioallantoic Membrane

Angiogenesis is the formation of new blood vessels from pre-existing vessels. Adequate oxygen transport and waste removal are necessary for tissue homeostasis. Restrictions in blood supply can lead to ischaemia which can contribute to disease pathology. Vascular endothelial growth factor (VEGF) is essential in angiogenesis and myogenesis, making it an ideal candidate for angiogenic and myogenic stimulation in muscle. We established C2C12 mouse myoblast cell lines which stably express elevated levels of (i) human VEGF-A and (ii) dual human FGF4-VEGF-A. Both stably transfected cells secreted increased amounts of human VEGF-A compared to non-transfected cells, with the latter greater than the former. In vitro, conditioned media from engineered cells resulted in a significant increase in endothelial cell proliferation, migration, and tube formation. In vivo, this conditioned media produced a 1.5-fold increase in angiogenesis in the chick chorioallantoic membrane (CAM) assay. Delivery of the engineered myoblasts on Matrigel demonstrated continued biological activity by eliciting an almost 2-fold increase in angiogenic response when applied directly to the CAM assay. These studies qualify the use of genetically modified myoblasts in therapeutic angiogenesis for the treatment of muscle diseases associated with vascular defects.

Acceleration of pelvic tissue generation by overexpression of basic fibroblast growth factor in stem cells

BACKGROUND

Pelvic organ prolapse (POP) is a common debilitating condition affecting approximately 30-40% of women. The FDA issued a warning about polypropylene mesh used for pelvic floor repair due to erosion, exposure and other complications and banned it in 2019. The application of stem cell therapy and growth factors has strongly promoted the development of pelvic tissue engineering.

PURPOSE

we intend to address the issues of direct application of growth factors, the side effects of long-term exogenous treatment, and the directional differentiation of stem cells. Methods: we evaluated the paracrine effects and directional differentiation of adipose mesenchymal stem cells through stable overexpression of basic fibroblast growth factor (bFGF).

RESULTS

we found that the modified stem cells could continuously and stably release bFGF in the initial stage and could spontaneously differentiate into fibroblasts with a high differentiation efficiency in the later stage.

CONCLUSION

following ADSCs are designed to continuously release controllable levels of growth factors during the control period of repair, taking advantage of the paracrine function of stem cells to accelerate cell growth and extracellular matrix (ECM) reconstruction during the early stage of stem cell implantation, and then stem cells are differentiated into target tissues-fibroblasts to accelerate the reconstruction of pelvic floor tissues, this study demonstrated the strong therapeutic potential of this approach for pelvic tissue engineering.

ABBREVIATIONS

POP: Pelvic organ prolapse; ADSCs: Adipose-derived stem cells; bFGF: Basic fibroblast growth factor; BMSCs: Bone marrow-derived mesenchymal stem cells; HUVECs: Human umbilical vein endothelial cells; EMSCs: Endometrial mesenchymal stem cells; VEGF: Vascular endothelial growth factor; PDGF: Platelet-derived growth factor ECM: Extracellular matrix; IGF: Insulin-like growth factor; HGF: Hepatocyte growth factor; EGF: Epidermal growth factor; BMP-2: Bone morphogenetic protein 2; FBR: Foreign body reaction.

Development and in vitro investigation of a biodegradable mesh for the treatment of stress urinary incontinence

Introduction and hypothesis

The use of polypropylene (PP) mesh for stress urinary incontinence (SUI) surgery has declined because of safety concerns. The aim of this study is to evaluate a biodegradable polycaprolactone (PCL) mesh and a PCL composite mesh tissue engineered with human uterine fibroblasts (HUFs) for SUI surgery by comparing mechanical properties and in vitro biocompatibility to commercially available PP and porcine dermis (PD).

Methods

The mechanical properties of four scaffold materials were evaluated: PCL, PCL-collagen-hyaluronic acid composite, acellular porcine dermal collagen (PD) (Pelvicol™) and polypropylene (Gynecare TVT™ Exact®). HUFs were seeded on separate scaffolds. After 7 and 14 days scaffolds were assessed for metabolic activity and cell proliferation using Alamar Blue, Live/Dead and PicoGreen assays. Soluble collagen production was evaluated using a Sircol assay.

Results

PCL and the composite scaffold reached ultimate tensile strength (UTS) values closest to healthy pelvic floor tissue (PCL = 1.19 MPa; composite = 1.13 MPa; pelvic floor = 0.79 MPa; Lei et al. Int Urogynecol J Pelvic Floor Dysfunct. 18(6):603-7, 2007). Cells on PCL showed significantly greater cell viability than PP at day 7 (p < 0.0001). At D14 the composite scaffold showed significantly greater cell viability than PP (p = 0.0006). PCL was the best performing scaffold for soluble collagen production at day 14 (106.1 μg versus 13.04 μg for PP, p = 0.0173).

Conclusions

We have designed a biodegradable PCL mesh and a composite mesh which demonstrate better biocompatibility than PP and mechanical properties closer to that of healthy pelvic floor tissue. This in vitro study provides promising evidence that these two implants should be evaluated in animal and human trials.

Controlled Release of Caffeic Acid and Pinocembrin by Use of nPSi-βCD Composites Improves Their Antiangiogenic Activity

Although polyphenols have great pharmacological potential, the main disadvantage is that they have low bioavailability at the desired site. Thus, the use of biocompatible systems for drug delivery is a strategy that is currently gaining great interest. The objective of this study is to evaluate the effect of microencapsulation of caffeic acid and pinocembrin on the antioxidant and antiangiogenic activity of both polyphenols, by the use of nPSi-βCD composite microparticles. For this HUVEC, cells were exposed to H₂O₂ and to treatments with polyphenols in solution and loaded in the composite microparticle. The polyphenols were incorporated into a microparticle using nanoporous silicon, chitosan and a β-cyclodextrin polymer as the biomaterial. The evaluation of the antiangiogenic effect of the treatments with polyphenols in solution and microencapsulated was carried out through functional tests, and the changes in the expression of target genes associated with the antioxidant pathway and angiogenesis was performed through qPCR. The results obtained show that the caffeic acid and pinocembrin have an antioxidant and antiangiogenic activity, both in solution as microencapsulated. In the caffeic acid, a greater biological effect was observed when it was incorporated into the nPSi-βCD composite microparticle. Our results suggest that the nPSi-βCD composite microparticle could be used as an alternative oral drug administration system.

Cell Technologies in the Stress Urinary Incontinence Correction

The scientific literature of recent years contains a lot of data about using multipotent stromal cells (MSCs) for urinary incontinence correction. Despite this, the ideal treatment method for urinary incontinence has not yet been created. The cell therapy results in patients and experimental animals with incontinence have shown promising results, but the procedures require further optimization, and more research is needed to focus on the clinical phase. The MSC use appears to be a feasible, safe, and effective method of treatment for patients with urinary incontinence. However, the best mode for application of cell technology is still under study. Most clinical investigations have been performed on only a few patients and during rather short follow-up periods, which, together with an incomplete knowledge of the mechanisms of MSC action, does not make it possible for their widespread implementation. The technical details regarding the MSC application remain to be identified in more rigorous preclinical and clinical trials.

Microvascular Experimentation in the Chick Chorioallantoic Membrane as a Model for Screening Angiogenic Agents including from Gene-Modified Cells

The chick chorioallantoic membrane (CAM) assay model of angiogenesis has been highlighted as a relatively quick, low cost and effective model for the study of pro-angiogenic and anti-angiogenic factors. The chick CAM is a highly vascularised extraembryonic membrane which functions for gas exchange, nutrient exchange and waste removal for the growing chick embryo. It is beneficial as it can function as a treatment screening tool, which bridges the gap between cell based in vitro studies and in vivo animal experimentation. In this review, we explore the benefits and drawbacks of the CAM assay to study microcirculation, by the investigation of each distinct stage of the CAM assay procedure, including cultivation techniques, treatment applications and methods of determining an angiogenic response using this assay. We detail the angiogenic effect of treatments, including drugs, metabolites, genes and cells used in conjunction with the CAM assay, while also highlighting the testing of genetically modified cells. We also present a detailed exploration of the advantages and limitations of different CAM analysis techniques, including visual assessment, histological and molecular analysis along with vascular casting methods and live blood flow observations.

Tissue engineering to treat pelvic organ prolapse

Pelvic organ prolapse (POP) is a frequent chronic illness, which seriously affects women's living quality. In recent years, tissue engineering has made superior progress in POP treatment, and biological scaffolds have received considerable attention. Nevertheless, pelvic floor reconstruction still faces severe challenges, including the construction of ideal scaffolds, the selection of optimal seed cells, and growth factors. This paper summarizes the recent progress of pelvic floor reconstruction in tissue engineering, and discusses the problems that need to be further considered and solved to provide references for the further development of this field.

Delivery of Bioactive Compounds to Improve Skin Cell Responses on Microfabricated Electrospun Microenvironments

The introduction of microtopographies within biomaterial devices is a promising approach that allows one to replicate to a degree the complex native environment in which human cells reside. Previously, our group showed that by combining electrospun fibers and additive manufacturing it is possible to replicate to an extent the stem cell microenvironment (rete ridges) located between the epidermal and dermal layers. Our group has also explored the use of novel proangiogenic compounds to improve the vascularization of skin constructs. Here, we combine our previous approaches to fabricate innovative polycaprolactone fibrous microtopographical scaffolds loaded with bioactive compounds (2-deoxy-D-ribose, 17β-estradiol, and aloe vera). Metabolic activity assay showed that microstructured scaffolds can be used to deliver bioactive agents and that the chemical relation between the working compound and the electrospinning solution is critical to replicate as much as possible the targeted morphologies. We also reported that human skin cell lines have a dose-dependent response to the bioactive compounds and that their inclusion has the potential to improve cell activity, induce blood vessel formation and alter the expression of relevant epithelial markers (collagen IV and integrin β1). In summary, we have developed fibrous matrixes containing synthetic rete-ridge-like structures that can deliver key bioactive compounds that can enhance skin regeneration and ultimately aid in the development of a complex wound healing device.

Validation of the 1,4-butanediol thermoplastic polyurethane as a novel material for 3D bioprinting applications

Tissue engineering (TE) seeks to fabricate implants that mimic the mechanical strength, structure, and composition of native tissues. Cartilage TE requires the development of functional personalized implants with cartilage-like mechanical properties capable of sustaining high load-bearing environments to integrate into the surrounding tissue of the cartilage defect. In this study, we evaluated the novel 1,4-butanediol thermoplastic polyurethane elastomer (b-TPUe) derivative filament as a 3D bioprinting material with application in cartilage TE. The mechanical behavior of b-TPUe in terms of friction and elasticity were examined and compared with human articular cartilage, PCL, and PLA. Moreover, infrapatellar fat pad-derived human mesenchymal stem cells (MSCs) were bioprinted together with scaffolds. in vitro cytotoxicity, proliferative potential, cell viability, and chondrogenic differentiation were analyzed by Alamar blue assay, SEM, confocal microscopy, and RT-qPCR. Moreover, in vivo biocompatibility and host integration were analyzed. b-TPUe demonstrated a much closer compression and shear behavior to native cartilage than PCL and PLA, as well as closer tribological properties to cartilage. Moreover, b-TPUe bioprinted scaffolds were able to maintain proper proliferative potential, cell viability, and supported MSCs chondrogenesis. Finally, in vivo studies revealed no toxic effects 21 days after scaffolds implantation, extracellular matrix deposition and integration within the surrounding tissue. This is the first study that validates the biocompatibility of b-TPUe for 3D bioprinting. Our findings indicate that this biomaterial can be exploited for the automated biofabrication of artificial tissues with tailorable mechanical properties including the great potential for cartilage TE applications.

Emerging Nano/Micro-Structured Degradable Polymeric Meshes for Pelvic Floor Reconstruction

Pelvic organ prolapse (POP) is a hidden women's health disorder that impacts 1 in 4 women across all age groups. Surgical intervention has been the only treatment option, often involving non-degradable meshes, with variable results. However, recent reports have highlighted the adverse effects of meshes in the long term, which involve unacceptable rates of erosion, chronic infection and severe pain related to mesh shrinkage. Therefore, there is an urgent unmet need to fabricate of new class of biocompatible meshes for the treatment of POP. This review focuses on the causes for the downfall of commercial meshes, and discusses the use of emerging technologies such as electrospinning and 3D printing to design new meshes. Furthermore, we discuss the impact and advantage of nano-/microstructured alternative meshes over commercial meshes with respect to their tissue integration performance. Considering the key challenges of current meshes, we discuss the potential of cell-based tissue engineering strategies to augment the new class of meshes to improve biocompatibility and immunomodulation. Finally, this review highlights the future direction in designing the new class of mesh to overcome the hurdles of foreign body rejection faced by the traditional meshes, in order to have safe and effective treatment for women in the long term.

Stress Urinary Incontinence and Pelvic Organ Prolapse: Biologic Graft Materials Revisited

Symptomatic stress urinary incontinence (SUI) and pelvic organ prolapse (POP) refractory to conservative management with pelvic floor muscle training or vaginal pessaries may warrant surgical intervention with different forms of biologic or synthetic material. However, in recent years, several global regulatory agencies have issued health warnings and recalled several mesh products due to an increase in complications such as mesh erosion, infection, chronic pain, and perioperative bleeding. At present, current surgical treatment strategies for SUI and POP are aimed at developing biological graft materials with similar mechanical properties to established synthetic meshes, but with improved tissue integration and minimal host response. This narrative review aims to highlight recent studies related to the development of biomimetic and biologic graft materials as alternatives to traditional synthetic materials for SUI/POP repair in female patients. We also investigate complications and technical limitations associated with synthetic mesh and biological biomaterials in conventional SUI and POP surgery. Our findings demonstrate that newly developed biologic grafts have a lower incidence of adverse events compared to synthetic biomaterials. However there remains a significant disparity between success in preclinical trials and long-term clinical translation. Further characterization on the optimal structural, integrative, and mechanical properties of biological grafts is required before they can be reliably introduced into clinical practice for SUI and POP surgery. Impact statement Our review article aims to outline the clinical history of developments and controversies associated with the use of synthetic mesh materials in the surgical treatment of stress urinary incontinence and pelvic organ prolapse, as well as highlighting recent advancements in the area of biological graft materials and their potential importance in an area that remains an enduring issue for patients and clinicians alike. This article aims to provide a concise summary of previous controversies in the field of urinary incontinence, while evaluating the future of potential biomaterials in this field.

Boosting the Osteogenic and Angiogenic Performance of Multiscale Porous Polycaprolactone Scaffolds by In Vitro Generated Extracellular Matrix Decoration

Tissue engineering (TE)-based bone grafts are favorable alternatives to autografts and allografts. Both biochemical properties and the architectural features of TE scaffolds are crucial in their design process. Synthetic polymers are attractive biomaterials to be used in the manufacturing of TE scaffolds, due to various advantages, such as being relatively inexpensive, enabling precise reproducibility, possessing tunable mechanical/chemical properties, and ease of processing. However, such scaffolds need modifications to improve their limited interaction with biological tissues. Structurally, multiscale porosity is advantageous over single-scale porosity; therefore, in this study, we have considered two key points in the design of a bone repair material; (i) manufacture of multiscale porous scaffolds made of photocurable polycaprolactone (PCL) by a combination of emulsion templating and three-dimensional (3D) printing and (ii) decoration of these scaffolds with the in vitro generated bone-like extracellular matrix (ECM) to create biohybrid scaffolds that have improved biological performance compared to PCL-only scaffolds. Multiscale porous scaffolds were fabricated, bone cells were cultured on them, and then they were decellularized. The biological performance of these constructs was tested in vitro and in vivo. Mesenchymal progenitors were seeded on PCL-only and biohybrid scaffolds. Cells not only showed improved attachment on biohybrid scaffolds but also exhibited a significantly higher rate of cell growth and osteogenic activity. The chick chorioallantoic membrane (CAM) assay was used to explore the angiogenic potential of the biohybrid scaffolds. The CAM assay indicated that the presence of the in vitro generated ECM on polymeric scaffolds resulted in higher angiogenic potential and a high degree of tissue infiltration. This study demonstrated that multiscale porous biohybrid scaffolds present a promising approach to improve bioactivity, encourage precursors to differentiate into mature bones, and to induce angiogenesis.

3D Printing of Drug-Loaded Thermoplastic Polyurethane Meshes: A Potential Material for Soft Tissue Reinforcement in Vaginal Surgery

Current strategies to treat pelvic organ prolapse (POP) or stress urinary incontinence (SUI), include the surgical implantation of vaginal meshes. Recently, there have been multiple reports of issues generated by these meshes conventionally made of poly(propylene). This material is not the ideal candidate, due to its mechanical properties leading to complications such as chronic pain and infection. In the present manuscript, we propose the use of an alternative material, thermoplastic polyurethane (TPU), loaded with an antibiotic in combination with fused deposition modelling (FDM) to prepare safer vaginal meshes. For this purpose, TPU filaments containing levofloxacin (LFX) in various concentrations (e.g., 0.25%, 0.5%, and 1%) were produced by extrusion. These filaments were used to 3D print vaginal meshes. The printed meshes were fully characterized through different tests/analyses such as fracture force studies, attenuated total reflection-Fourier transform infrared, thermal analysis, scanning electron microscopy, X-ray microcomputed tomography (μCT), release studies and microbiology testing. The results showed that LFX was uniformly distributed within the TPU matrix, regardless the concentration loaded. The mechanical properties showed that poly(propylene) (PP) is a tougher material with a lower elasticity than TPU, which seemed to be a more suitable material due to its elasticity. In addition, the printed meshes showed a significant bacteriostatic activity on both Staphylococcus aureus and Escherichia coli cultures, minimising the risk of infection after implanting them. Therefore, the incorporation of LFX to the TPU matrix can be used to prepare anti-infective vaginal meshes with enhanced mechanical properties compared with current PP vaginal meshes.

The vaginal microcirculation after prolapse surgery

Aims

Oxygen plays a crucial role in wound healing after prolapse surgery. Trauma to the vaginal vasculature might limit the delivery of oxygen to the surgical wound, which may negatively affect wound healing and regeneration of connective tissue. This possibly increases the future risk of recurrence. We aimed to determine the effects of vaginal prolapse surgery on the microcirculation of the vaginal wall.

Methods

We evaluated the vaginal microcirculation in healthy participants without known vascular disease undergoing anterior and/or posterior colporrhaphy. We used incident dark‐field imaging for in vivo assessment before and after (1 day, 2 weeks, and 6 weeks) surgery. We studied perfusion (microvascular flow index [MFI]), angioarchitecture (morphology/layout of microvessels) and capillary density.

Results

Ten women were included. Interindividual differences were observed 1 day postoperatively with regard to perfusion and angioarchitecture. Microvascular flow at the surgical site was absent or significantly reduced in some participants, whereas normal microvascular flow was observed in others (MFI range 0–3). Perfusion and angioarchitecture had been restored in all participants after 6 weeks (MFI range 2–3), regardless of the extent of vascular trauma 1 day postoperatively.

Conclusions

The difference in the extent of vascular trauma between women undergoing seemingly identical surgical procedures suggests that some individuals are more susceptible to vascular trauma than others. Delivery of oxygen to the wound and subsequent wound healing may be compromised in these cases, which could be related to the development of anatomical recurrence. Future studies should investigate whether there is a relationship between the vaginal microvasculature and the recurrence of prolapse.

Landmarks in vaginal mesh development: polypropylene mesh for treatment of SUI and POP

Vaginal meshes used in the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) have produced highly variable outcomes, causing life-changing complications in some patients while providing others with effective, minimally invasive treatments. The risk:benefit ratio when using vaginal meshes is a complex issue in which a combination of several factors, including the inherent incompatibility of the mesh material with some applications in pelvic reconstructive surgeries and the lack of appropriate regulatory approval processes at the time of the premarket clearance of these products, have contributed to the occurrence of complications caused by vaginal mesh. Surgical mesh used in hernia repair has evolved over many years, from metal implants to knitted polymer meshes that were adopted for use in the pelvic floor for treatment of POP and SUI. The evolution of the material and textile properties of the surgical mesh was guided by clinical feedback from hernia repair procedures, which were also being modified to obtain the best outcomes with use of the mesh. Current evidence shows how surgical mesh fails biomechanically when used in the pelvic floor and materials with improved performance can be developed using modern material processing and tissue engineering techniques.

A shape-memory and spiral light-emitting device for precise multisite stimulation of nerve bundles

We previously demonstrated that for long-term spastic limb paralysis, transferring the seventh cervical nerve (C7) from the nonparalyzed side to the paralyzed side results in increase of 17.7 in Fugl-Meyer score. One strategy for further improvement in voluntary arm movement is selective activation of five target muscles innervated by C7 during recovery process. In this study, we develop an implantable multisite optogenetic stimulation device (MOSD) based on shape-memory polymer. Two-site stimulation of sciatic nerve bundles by MOSD induces precise extension or flexion movements of the ankle joint, while eight-site stimulation of C7 nerve bundles induce selective limb movement. Long-term implant of MOSD to mice with severed and anastomosed C7 nerve is proven to be both safe and effective. Our work opens up the possibility for multisite nerve bundle stimulation to induce highly-selective activations of limb muscles, which could inspire further applications in neurosurgery and neuroscience research.

Optogenetic stimulation of damaged peripheral nerves has advantages over electrical stimulation but it’s limited to single-site stimulation. Here the authors develop a spiral-shaped LED implant for precise optogenetic stimulation of peripheral nerve bundles at multiple sites and use it to induce distinct limb movements in mice.

Mesenchymal stem cell-based bioengineered constructs: foreign body response, cross-talk with macrophages and impact of biomaterial design strategies for pelvic floor disorders

An excessive foreign body response (FBR) has contributed to the adverse events associated with polypropylene mesh usage for augmenting pelvic organ prolapse surgery. Consequently, current biomaterial research considers the critical role of the FBR and now focuses on developing better biocompatible biomaterials rather than using inert implants to improve the clinical outcomes of their use. Tissue engineering approaches using mesenchymal stem cells (MSCs) have improved outcomes over traditional implants in other biological systems through their interaction with macrophages, the main cellular player in the FBR. The unique angiogenic, immunomodulatory and regenerative properties of MSCs have a direct impact on the FBR following biomaterial implantation. In this review, we focus on key aspects of the FBR to tissue-engineered MSC-based implants for supporting pelvic organs and beyond. We also discuss the immunomodulatory effects of the recently discovered endometrial MSCs on the macrophage response to new biomaterials designed for use in pelvic floor reconstructive surgery. We conclude with a focus on considerations in biomaterial design that take into account the FBR and will likely influence the development of the next generation of biomaterials for gynaecological applications.

Using ex Ovo Chick Chorioallantoic Membrane (CAM) Assay To Evaluate the Biocompatibility and Angiogenic Response to Biomaterials

Biomaterials need to be vigorously tested at every stage of preclinical development. As demand for in vivo culture environments continues to increase, traditional animal models are often technically complex, ethically undesirable, time-consuming, and resource intensive and thus present a barrier to high throughput screening. The chick chorioallantoic membrane (CAM) assay has long been used to study the effects of drugs on angiogenesis in vivo, providing researchers with a readily available, accessible, self-sustaining, and high throughput screen without requiring animal facilities. It has also been recognized as an in vivo assay to test initial tissue response to biomaterials; however it has not yet gained widespread acceptance. This could be due to lack of specific protocols on how to optimize this assay to specifically test biomaterials. Here we describe how the ex ovo (shell-less) CAM assay can be effectively used to study the angiogenic potential and initial tissue response to biomaterials. In comparison to alternative in vivo approaches, this technique provides additional advantages to the researcher as it allows better visualization of implanted biomaterials and the ability to implant several samples simultaneously enabling combinatorial biomaterial assays to be conducted.

Recent advances in pelvic floor repair

Stress urinary incontinence (SUI) and pelvic organ prolapse (POP) are conditions which result in significant physical, mental and social consequences for women worldwide. The high rates of recurrence reported with primary repair for POP led to the use of synthetic mesh to augment repairs in both primary and secondary cases following failed previous POP repair. The widely reported, unacceptably high rates of complications associated with the use of synthetic, transvaginal mesh in pelvic floor repair have severely limited the treatment options that surgeons can offer. This article summarises the recent advances in pelvic floor repair, such as improved quantification and modelling of the biomechanics of the pelvic floor and the developing technology within the field of tissue engineering for treatment of SUI/POP, including biomaterials and cell-based therapies. Finally, we will discuss the issues surrounding the commercial introduction of synthetic mesh for use within the pelvic floor and what lessons can be learned for the future as well as the current guidance surrounding treatment for SUI/POP.

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

PURPOSE OF REVIEW

The present article reviews the history of mesh-related complications and regulations in SUI and POP repair settings, clinical outcomes associated with the use of biologic and synthetic mesh materials, and novel approaches using modified mesh materials.

RECENT FINDINGS

Treatment of pelvic floor disorders, such as stress urinary incontinence (SUI) and pelvic organ prolapse (POP) commonly involves implantation of synthetic surgical mesh materials like polypropylene. Many synthetic mesh materials, however, are associated with a foreign body response upon implantation, which is characterized by fibrotic encapsulation. Complications, including erosion, infections, bleeding, and chronic pain, have led to warnings by regulatory agencies and the recall of several mesh products. To mitigate such complications, biologic mesh materials have been proposed as alternatives for SUI and POP repair.

SUMMARY

Clinical outcomes of surgical repair of POP/SUI are similar between biologic and synthetic meshes, but biologic meshes have a lower incidence of adverse effects. Several strategies for modifying or functionalizing biological and synthetic meshes have shown promising results in preclinical studies.

Improving the biocompatibility of biomaterial constructs and constructs delivering cells for the pelvic floor

PURPOSE OF REVIEW

Interactions between biomaterials and biomaterial-delivering cells and the host tissues are complexly affected by the material itself, the ultrastructure of the overall construct and cells and other bioactive factors involved. The aim of this review is to review the current understanding on the definitions of biocompatibility and current advances in improving biocompatability of tissue-engineered constructs.

RECENT FINDINGS

Some synthetic materials are associated with more foreign body reactions compared with natural materials; however, they allow fabrication of materials with a great diversity of physical and mechanical properties. Material design strategies can be tailored to mimic the natural extracellular matrix topography. There are also advancements in the pharmacological functionalization of materials with improved angiogenic potential that can lead to better tissue response. Stem cells are also used to improve the tissue response of tissue-engineered materials; however, the recent regulations on regenerative medicine products necessitate significant regulatory approval processes for these.

SUMMARY

The biggest challenge faced in translation of tissue-engineered constructs into clinical practice relates to their engraftment and poor tissue integration into the challenging wound bed of the pelvic floor. Biocompatibility of tissue engineered constructs can theoretically be improved by the incorporation of bioactive agents, such as vitamins C or oestradiol.

Exploration of 2-deoxy-D-ribose and 17β-Estradiol as alternatives to exogenous VEGF to promote angiogenesis in tissue-engineered constructs

Aim: In this study, we explored the angiogenic potential and proangiogenic concentration ranges of 2-deoxy-D-ribose (2dDR) and 17β-Estradiol (E2) in comparison with VEGF. The 2dDR and E2 were then loaded into tissue engineering (TE) scaffolds to investigate their proangiogenic potential when released from fibers. Materials & methods: Ex ovo chick chorioallantoic membrane (CAM) assay was used to evaluate angiogenic activity of 2dDR and E2. Both factors were then introduced into scaffolds via electrospinning to assess their angiogenic potential when released from fibers. Results: Both factors were approximately 80% as potent as VEGF and showed a dose-dependent angiogenic response. The sustained release of both agents from the scaffolds stimulated neovascularization over 7 days in the chorioallantoic membrane assay. Conclusion: We conclude that both 2dDR and E2 provide attractive alternatives to VEGF for the functionalization of tissue engineering scaffolds to promote angiogenesis in vivo.

Complications related to use of mesh implants in surgical treatment of stress urinary incontinence and pelvic organ prolapse: infection or inflammation?

The surgical mesh material used in the surgical treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) in women is associated with significant complications in some women. This has recently become a public health issue with involvement of national parliaments and regulatory bodies. The occurrence of mesh complications is thought to be a result of multifactorial processes involving problems related to the material design, the surgical techniques used and disease, and patient-related factors. However, the infectious complications and mesh–tissue interactions are least studied. The aim of this article is to review any previous clinical and basic scientific evidence about the contribution of infectious and inflammatory processes to the occurrence of mesh-related complications in SUI and POP. A literature search for the relevant publications without any time limits was performed on the Medline database. There is evidence to show that vaginal meshes are associated with an unfavourable host response at the site of implantation. The underlying mechanisms leading to this type of host response is not completely clear. Mesh contamination with vaginal flora during surgical implantation can be a factor modifying the host response if there is a subclinical infection that can trigger a sustained inflammation. More basic science research is required to identify the biological mechanisms causing a sustained inflammation at the mesh–tissue interface that can then lead to contraction, mesh erosion, and pain.

[The gynecological pessary: Is it really a device of another age, a fig leaf?]

OBJECTIVES

The use of pessary to put back up prolapsed organs to their normal position dates back prior to several millennia. This work aims to discuss its place in our clinical practice through an updated bibliographic review and emphasizes a hands-on approach to pessary fitting and management in terms of indication, pessary type selection, device' size, insertion, removal, follow-up visits and care.

METHODS

A review of the literature, in the light of the latest publications and recommendations of French and international learned societies, as well as our own experience, were analyzed.

RESULTS

This device appears to be as effective as surgical management to relieve symptoms related to urogenital prolapse and restore body image. It can be used temporarily, awaiting a surgical solution or as a therapeutic test (mimicking the effect of a surgical procedure to predict its functional outcome or identifying a masked urinary incontinence). It can also represent an alternative to surgery (patient choice, women who wish to complete childbearing or who are unsuitable for surgery because of medical comorbidities) and thus can be used in first intention. However, despite its moderate cost and its harmlessness, this device remains somewhat little known as regards the practical modalities of its use, which, moreover, appear not consensual.

CONCLUSION

A guide intended for the attention of the patients as well as a film relating to the practical modalities of the device' use were elaborated to improve the knowledge of both professionals and users in order to optimize and secure the care pathway.