Tissue engineering in female pelvic floor reconstruction

Conserved and tissue-specific immune responses to biologic scaffold implantation

Upon implantation into a patient, any biomaterial induces a cascade of immune responses that influences the outcome of that device. This cascade depends upon several factors, including the composition of the material itself and the location in which the material is implanted. There is still significant uncertainty around the role of different tissue microenvironments in the immune response to biomaterials and how that may alter downstream scaffold remodeling and integration. In this study, we present a study evaluating the immune response to decellularized extracellular matrix materials within the intraperitoneal cavity, the subcutaneous space, and in a traumatic skeletal muscle injury microenvironment. All different locations induced robust cellular recruitment, specifically of macrophages and eosinophils. The latter was most prominent in the subcutaneous space. Intraperitoneal implants uniquely recruited B cells that may alter downstream reactivity as adaptive immunity has been strongly implicated in the outcome of scaffold remodeling. These data suggest that the location of tissue implants should be taken together with the composition of the material itself when designing devices for downline therapeutics. STATEMENT OF SIGNIFICANCE: Different tissue locations have unique immune microenvironments, which can influence the immune response to biomaterial implants. By considering the specific immune profiles of the target tissue, researchers can develop implant materials that promote better integration, reduce complications, and improve the overall outcome of the implantation process.

The properties of absorbable scaffold harvested with human amniotic fluid stem cells on rat model: an innovation for pelvic reconstruction surgery

The current practice of restoring the anatomical structure in the treatment of pelvic floor dysfunction includes implantation of synthetic sling, which carries potential complications. This study aimed to develop biological substitutes to improve tissue function using scaffolds as a support to the host cells, through formation of new tissue. Human amniotic fluid stem cells (hAFSCs) were seeded on synthetic mesh-scaffold of AlloDerm Regenerative Tissue Matrix (RTM), Poly-DL-lactico-glycolic acid (PLGA) mesh (VICRYL) and Polydioxanone (PDS) meshes. In vitro study evaluates the metabolic activity of hAFSCs seeded mesh-scaffolds. In vivo study involving Sprague-Dawley rats was performed by assigning into 7 groups of sham control with fascia operation, AlloDerm implant, PDS implant, PLGA implant, AlloDerm harvest with hAFSC (AlloDerm-SC), PDS harvest with hAFSC(PDS-SC) and PLGS harvest with hAFSC (PGLA-SC). In vitro study reveals cell viability and proliferation of hAFSC on mesh scaffolds varies between meshes, with AlloDerm growing the fastest. The biomechanical properties of tissue-mesh-complex tension strength declined over time, showing highest tension strength on week-1, deteriorated similar to control group on week-12. All hAFSC-seeded mesh provides higher tension strength, compared to without. This study shed the potential of synthetic mesh as a scaffold for hAFSC for the surgical treatment of pelvic floor dysfunction.

Recent progresses in natural based therapeutic materials for Alzheimer's disease

Alzheimer's disease is a neurological disorder that causes increased memory loss, mood swings, behavioral disorders, and disruptions in daily activities. Polymer scaffolds for the brain have been grown under laboratory, physiological, and pathological circumstances because of the limitations of conventional treatments for patients with central nervous system diseases. The blood-brain barrier prevents medications from entering the brain, challenging AD treatment. Numerous biomaterials such as biomolecules, polymers, inorganic metals, and metal oxide nanoparticles have been used to transport therapeutic medicines into the nervous system. Incorporating biocompatible materials that support neurogenesis through a combination of topographical, pharmacological, and mechanical stimuli has also shown promise for the transfer of cells to replenish dopaminergic neurons. Components made of naturally occurring biodegradable polymers are appropriate for the regeneration of nerve tissue. The ability of natural-based materials (biomaterials) has been shown to promote endogenous cell development after implantation. Also, strategic functionalization of polymeric nanocarriers could be employed for treating AD. In particular, nanoparticles could resolve Aβ aggregation and thus help cure Alzheimer's disease. Drug moieties can be effectively directed to the brain by utilizing nano-based systems and diverse colloidal carriers, including hydrogels and biodegradable scaffolds. Notably, early investigations employing neural stem cells have yielded promising results, further emphasizing the potential advancements in this field. Few studies have fully leveraged the combination of cells with cutting-edge biomaterials. This study provides a comprehensive overview of prior research, highlighting the pivotal role of biomaterials as sophisticated drug carriers. It delves into various intelligent drug delivery systems, encompassing pH and thermo-triggered mechanisms, polymeric and lipid carriers, inorganic nanoparticles, and other vectors. The discussion synthesizes existing knowledge and underscores the transformative impact of these biomaterials in devising innovative strategies, augmenting current therapeutic methodologies, and shaping new paradigms in the realm of Alzheimer's disease treatment.

Three-Dimensional Printing of Polycaprolactone/Nano-Hydroxyapatite Composite Scaffolds with a Pore Size of 300/500 µm is Histocompatible and Promotes Osteogenesis Using Rabbit Cortical Bone Marrow Stem Cells

BACKGROUND Many patients have bone defects that exceed the healing size. This study aimed to construct polycaprolactone/nano-hydroxyapatite (PCL/nHA) composite scaffolds with different pore sizes and investigate the osteogenesis and histocompatibility of cortical bone mesenchymal stem cells (BMSCs-C) seeded on it after inoculation. MATERIAL AND METHODS After mixing PCL and nHA proportionally, three-dimensional (3D) printing was used to print scaffolds. Porosity, compressive strength, and elastic modulus of PCL/nHA scaffolds were tested. The proliferation of BMSCs-C cells was examined and osteogenesis, chondrogenesis, and adipogenesis were evaluated. BMSCs-C cells were inoculated into 3D printing scaffolds, and histocompatibility between BMSCs-C cells and scaffolds was observed by the cell count kit (CCK-8) assay and LIVE/DEAD staining. After inoculating BMSCs-C cells into scaffolds, alkaline phosphatase (ALP) activity and calcium content were measured. RESULTS There was no obvious difference in characteristics between the 3 PCL/nHA composite scaffolds. The porosity, compressive strength, and elastic modulus of the 300/500-μm scaffold were between those of the 300-μm and 500-μm scaffolds. With increasing pore size, the mechanical properties of the scaffold decrease. BMSCs-C cells demonstrated faster growth and better osteogenic, adipogenic, and chondrogenic differentiation; therefore, BMSCs-C cells were selected as seed cells. PCL/nHA composite scaffolds with different pore sizes had no obvious toxicity and demonstrated good biocompatibility. All scaffolds showed higher ALP activity and calcium content. CONCLUSIONS The 300/500 μm mixed pore size scaffold took into account the mechanical properties of the 300 μm scaffold and the cell culture area of the 500 μm scaffold, therefore, 300/500 μm scaffold is a better model for the construction of tissue engineering scaffolds.

Supramolecular Fibrous Hydrogel Augmentation of Uterosacral Ligament Suspension for Treatment of Pelvic Organ Prolapse

Uterosacral ligament suspension (USLS) is a common surgical treatment for pelvic organ prolapse (POP). However, the relatively high failure rate of up to 40% underscores a strong clinical need for complementary treatment strategies, such as biomaterial augmentation. Herein, the first hydrogel biomaterial augmentation of USLS in a recently established rat model is described using an injectable fibrous hydrogel composite. Supramolecularly-assembled hyaluronic acid (HA) hydrogel nanofibers encapsulated in a matrix metalloproteinase (MMP)-degradable HA hydrogel create an injectable scaffold showing excellent biocompatibility and hemocompatibility. The hydrogel can be successfully delivered and localized to the suture sites of the USLS procedure, where it gradually degrades over six weeks. In situ mechanical testing 24 weeks post-operative in the multiparous USLS rat model shows the ultimate load (load at failure) to be 1.70 ± 0.36 N for the intact uterosacral ligament (USL), 0.89 ± 0.28 N for the USLS repair, and 1.37 ± 0.31 N for the USLS + hydrogel (USLS+H) repair (n = 8). These results indicate that the hydrogel composite significantly improves load required for tissue failure compared to the standard USLS, even after the hydrogel degrades, and that this hydrogel-based approach can potentially reduce the high failure rate associated with USLS procedures.

The Effect of Growth Factors on Vaginal Wound Healing: A Systematic Review and Meta-analysis

Surgical outcomes of pelvic organ prolapse (POP) surgery are poor, resulting in a 20% recurrence risk. Following the hypothesis that impaired wound healing is the main determinant of recurrent POP, growth factors have the potential to promote wound healing and may improve surgical outcomes. In this study, we systematically reviewed the effect of growth factors on vaginal wound healing in both in vitro and animal studies. For each independent comparison, the standardized mean difference and 95% CI were calculated using the Hedges' g correction. Of the 3858 retrieved studies, seven studies were included, of which six were included in meta-analysis (three in vitro studies and four in vivo studies). In vitro, basic fibroblast growth factor (bFGF) promotes proliferation, differentiation, and collagen types I and III production. Epidermal growth factor stimulates proliferation and connective tissue growth factor promotes Tenascin-C expression. These effects, however, are less pronounced in vivo; only bFGF slightly promotes collagen production. The review shows that growth factors, particularly bFGF, are able to promote vaginal wound healing in vitro. The uncertain in vivo findings suggest that preclinical models should be improved. The ultimate goal is to develop effective growth factor-supplemented therapies that improve surgical outcomes for POP.

Extracellular Matrix-Based and Electrospun Scaffolding Systems for Vaginal Reconstruction

Congenital vaginal anomalies and pelvic organ prolapse affect different age groups of women and both have significant negative impacts on patients' psychological well-being and quality of life. While surgical and non-surgical treatments are available for vaginal defects, their efficacy is limited, and they often result in long-term complications. Therefore, alternative treatment options are urgently needed. Fortunately, tissue-engineered scaffolds are promising new treatment modalities that provide an extracellular matrix (ECM)-like environment for vaginal cells to adhere, secrete ECM, and be remodeled by host cells. To this end, ECM-based scaffolds or the constructs that resemble ECM, generated by self-assembly, decellularization, or electrospinning techniques, have gained attention from both clinicians and researchers. These biomimetic scaffolds are highly similar to the native vaginal ECM and have great potential for clinical translation. This review article aims to discuss recent applications, challenges, and future perspectives of these scaffolds in vaginal reconstruction or repair strategies.

Evaluation of the clinical effectiveness of modified sacrospinous ligament fixation via the anterior vaginal wall path for pelvic organ prolapse: A feasibility report based on 50 patients

Objective

To describe the surgical techniques and short-term outcomes for 50 cases of modified sacrospinous ligament fixation via the anterior vaginal wall path for pelvic organ prolapse

Methods

100 patients with pelvic organ prolapse (stage III or stage IV based on POP-Q staging) from January 2018 to January 2020 were retrospectively analyzed. Among them, 50 patients received modified sacrospinous ligament fixation via the anterior vaginal wall path for pelvic organ prolapse (mSSLF group), while the other 50 patients received pelvic reconstruction using T4 mesh (T4 group). Operative time, blood loss, postoperative POP-Q score, length of the hospital stay, complications, and postoperative pain were compared between the two groups.

Results

The duration of the operation in mSSLF group was (50 ± 15.2 min), which was shorter than that of the T4 group (60 ± 14.8 min) (p = 0.02). No intraoperative complications were reported from the mSSLF group, whereas one vascular injury occurred in the T4 group. In both groups, postoperative pain and painful intercourse was significantly lower in the mSSLF group than in the SSLF group (p < 0.001). The exposed mesh rate was lower than T4 group.

Conclusions

The rates of intraoperative complications, postoperative pain and mesh erosion were significantly lower than those of the T4 group, but there was no significant difference in the efficacy and safety of the treatment of pelvic organ prolapse. So mSSLF may be a feasible technique to manage severe prolapse, with promising short-term efficacy and safety.

Tissue Engineering in Gynecology

Female gynecological organ dysfunction can cause infertility and psychological distress, decreasing the quality of life of affected women. Incidence is constantly increasing due to growing rates of cancer and increase of childbearing age in the developed world. Current treatments are often unable to restore organ function, and occasionally are the cause of female infertility. Alternative treatment options are currently being developed in order to face the inadequacy of current practices. In this review, pathologies and current treatments of gynecological organs (ovaries, uterus, and vagina) are described. State-of-the-art of tissue engineering alternatives to common practices are evaluated with a focus on in vivo models. Tissue engineering is an ever-expanding field, integrating various domains of modern science to create sophisticated tissue substitutes in the hope of repairing or replacing dysfunctional organs using autologous cells. Its application to gynecology has the potential of restoring female fertility and sexual wellbeing.

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.

Role of Fibroblasts and Myofibroblasts on the Pathogenesis and Treatment of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is a multifactorial connective tissue disorder caused by damage to the supportive structures of the pelvic floor, leading to the descent of pelvic organs in the vagina. In women with POP, fibroblast function is disturbed or altered, which causes impaired collagen metabolism that affects the mechanical properties of the tissue. Ideal surgical repair, either native tissue repair or POP surgery using an implant, aims to create a functional pelvic floor that is load-bearing, activating fibroblasts to regulate collagen metabolism without creating fibrotic tissue. Fibroblast function plays a crucial role in the pathophysiology of POP by directly affecting the connective tissue quality. On the other hand, fibroblasts determine the success of the POP treatment, as the fibroblast-to-(myo)fibroblast transition is the key event during wound healing and tissue repair. In this review, we aim to resolve the question of “cause and result” for the fibroblasts in the development and treatment of POP. This review may contribute to preventing the development and progress of anatomical abnormalities involved in POP and to optimizing surgical outcomes.

Update in Transvaginal Grafts: The Role of Lightweight Meshes, Biologics, and Hybrid Grafts in Pelvic Organ Prolapse Surgery

Transvaginal mesh/grafts have been popularized over the past 20 years in an attempt to improve the longevity of traditional vaginal pelvic organ prolapse (POP) surgery. Several national bodies have concluded that the proposed benefits of mesh/graft implantation are outweighed by the significant increase in surgery complications related to these products. As a consequence mesh products for vaginal POP surgery have been withdrawn from use in many countries. This article is a narrative review of newer mesh and graft products including lightweight polypropylene mesh products, biological grafts, hybrid grafts, and tissue engineered grafts.

Scaffold strategies combined with mesenchymal stem cells in vaginal construction: a review

Tissue engineering has provided new treatment alternatives for tissue reconstruction. Advances in the tissue engineering field have resulted in mechanical support and biological substitutes to restore, maintain or improve tissue/organs structures and functions. The application of tissue engineering technology in the vaginal reconstruction treatment can not only provide mechanical requirements, but also offer tissue repairing as an alternative to traditional approaches. In this review, we discuss recent advances in cell-based therapy in combination with scaffolds strategies that can potentially be adopted for gynaecological transplantation.

A Review of Zein as a Potential Biopolymer for Tissue Engineering and Nanotechnological Applications

Tissue engineering (TE) is one of the most challenging fields of research since it provides current alternative protocols and materials for the regeneration of damaged tissue. The success of TE has been mainly related to the right selection of nano-sized biocompatible materials for the development of matrixes, which can display excellent anatomical structure, functionality, mechanical properties, and histocompatibility. Today, the research community has paid particular attention to zein as a potential biomaterial for TE applications and nanotechnological approaches. Considering the properties of zein and the advances in the field, there is a need to reviewing the current state of the art of using this natural origin material for TE and nanotechnological applications. Therefore, the goal of this review paper is to elucidate the latest (over the last five years) applications and development works in the field, including TE, encapsulations of drugs, food, pesticides and bandaging for external wounds. In particular, attention has been focused on studies proving new breakthroughs and findings. Also, a complete background of zein’s properties and features are addressed.