Acellular Scaffolds Research Articles

The Goat as a Model for Temporomandibular Joint Disc Replacement: Techniques for Scaffold Fixation

A state-of-the-art scaffold capable of efficiently reconstructing the temporomandibular joint (TMJ) disc after discectomy remains elusive. The major challenge has been to identify a degradable scaffold that remodels into a TMJ disc-like tissue, and prevents increased joint pathology, among other significant complications. Tissue engineering research provides a foundation for promising approaches toward the creation of successful implants/scaffolds aiming to restore the TMJ disc. In light of improving the quality of life of patients who undergo TMJ disc removal, it is critical to establish a preclinical animal model to evaluate the properties of promising scaffolds implanted post-discectomy and to determine the most efficient implantation procedures to ensure a more reliable in-depth evaluation of the biomaterial replacing the articular disc. The present study evaluated the outcomes of two protocols for the implantation of an acellular scaffold composed of an extracellular matrix (ECM) derived from the small intestinal submucosa (SIS) of the pig, as a regenerative template for the TMJ disc in a goat model. The outcomes suggest that leaving one-half of the disc medially will allow anchoring the device to the medial aspect of the joint while avoiding lateral displacement of the ECM scaffold. The goat model is ideal to assess the longevity of tissue-engineered solutions for the TMJ disc as the goat chews for 12-16 hours a day. This study provides an important reference for selecting a suitable scaffold implantation procedure and the goat model for the development of new strategies to assess TMJ disc regeneration.

Stem cell seeding of decellularised porcine right ventricular outflow tracts to advance repair of congenital heart defects

Abstract Background Replacement of the right ventricular outflow tract (RVOT) is necessary in many critical congenital heart disease subtypes, often when the child is less than one year old. Poor availability of small-diameter cardiac homografts necessitates the use of xenografts in paediatric surgical reconstruction. Currently used xenografts are limited by immunoincompatibility and lack of growth, requiring repeat surgery to replace the defective graft. One approach to tackle acute immune rejection of animal tissue is aldehyde fixation of grafts prior to xenotransplantation. Though masking antigenicity, fixation is associated with multiple issues, including toxicity of fixative remnants and calcification. Decellularisation of biological grafts to remove foreign material is a promising alternative to reduce immunogenicity and dampen the risk of rejection. To combat lack of growth, in vitro cellularisation with stem cells is a promising solution. Purpose Current RVOT substitutes have not proven to be a lifelong solution for paediatric cardiac repair. This research has optimised a novel decellularisation technique for porcine RVOTs to produce a durable and cell-free scaffold with translational capability. Current work is looking to seed mesenchymal stem cells (MSCs) onto the acellular RVOT in vitro to enhance immune tolerance and endow the graft with growth capacity upon implant. Methods First, this decellularisation technique produces acellular RVOT scaffolds by simultaneously utilising three methods: enzymatic, chemical, and mechanical decellularisation. Novel to this method, the latter is realised using a 3D printed flow chamber to utilise the shear forces of continuous fluid flow for cell removal from the external and internal RVOTs structure. Coating the acellular graft with poly-lysine has then enabled recellularisation with MSCs isolated from the umbilical cord. Results Nuclei quantification demonstrates decellularisation of all structures of the RVOT, and elimination of residual nucleic acids is evidenced. Immunohistochemical analysis confirms the xenoantigen Galα1-3Galβ1-4GlcNAc-R is absent from the decellularised tissue. In parallel with removal of typical immunogens associated with the rejection response, the elastin and collagen fibres of the extracellular matrix are maintained, supported by histology and electron microscopy. Importantly, the tensile properties of the decellularised grafts are preserved. Finally, MSCs adhered onto the external pulmonary artery surface in vitro, achieving a uniform monolayer of cells. Conclusion RVOTs have been successfully decellularised and proven to possess seeding potential. Future work aims to characterise the seeded MSCs to assess parameters including proliferative capacity and expression of typical MSC markers. Overall, this work has the potential to produce a non-immunogenic graft possessing growth potential as a surgical alternative for paediatric RVOT replacement.

Cartilage Laser Engraving for Fast-Track Tissue Engineering of Auricular Grafts.

In this study, the optimal engraving parameters were determined through the analysis of scanning electron microscopy (SEM) data, as follows: a laser power density of 5.5 × 105 W/cm2, an irradiation rate of 0.1 mm/s, a well radius of 60 μm, a distance between well centers of 200 μm, and a number of passes for each well of 20. After 1 week of in vitro cultivation, chondrocytes were located on the surface of the scaffolds, in the sockets and lacunae of decellularized cartilage. When implanted into animals, both cellular and acellular scaffolds were able to support cartilage in-growth and complete regeneration of the defect without clear boundaries with normal tissue. Nevertheless, the scaffolds populated with cells exhibited superior biocompatibility and were not subject to rejection, in contrast to cell-free constructs.

Evaluation the Impressionability of Acellular Scaffolds in Presence of Different Combination of Umbilical Cord Blood Stem Cells and Platelet Rich Fibrin in Repair of Knee Defects in Rabbit (Novel Method with Xeno-Material Elements

Background: Currently, the use of xenogeneic and allogeneic compounds in the treatment of musculoskeletal diseases is common. Repairing bone and cartilage remains a significant challenge for orthopedic surgeons. One of the principal goals of tissue engineering is the development of appropriate scaffolds that can promote tissue regeneration. Various cells and genes are involved in bone and cartilage regeneration, and new scaffolds can induce these processes during osteoregeneration. Objectives: The aim of this study is to evaluate the effects of umbilical cord blood stem cells (USCs) and platelet-rich fibrin (PRF) using acellular scaffolds in the repair of knee defects in rabbits. Methods: In this study, the femoral patella of 12 male New Zealand rabbits was drilled, and they were divided into four groups: (1) control (rabbits with femoral defects), (2) acellular osteochondral (AO), (3) AO + PRF, and (4) AO + USCs / platelet-rich fibrin. Different scaffolds were implanted into their knees, and after six months, histological evaluations were conducted. To further investigate the effects of scaffolds on bone and cartilage, gene expression levels of Col 1, Col X, Runx2, SOX9, and ALP were measured using real-time PCR. Results: All the implanted materials contributed to knee repair. In terms of statistical analysis, the use of USCs and platelet-rich fibrin with natural scaffolds such as Acellular Osteochondral provided better results for repairing bone and cartilage. The evaluation of specific bone regeneration genes (COLI, RUNX2) and the histological results from the implanted site in experimental osteochondral defects indicated that the most effective knee repair occurred in the group treated with cell-free osteochondral scaffolds, USCs, and platelet-rich fibrin. Conclusions: This study demonstrates that the combination of biomaterials and xenografts can accelerate the regeneration process.

A mouse model of volumetric muscle loss and therapeutic scaffold implantation.

Skeletal myofibers naturally regenerate after damage; however, impaired muscle function can result in cases when a prominent portion of skeletal muscle mass is lost, for example, following traumatic muscle injury. Volumetric muscle loss can be modeled in mice using a surgical model of muscle ablation to study the pathology of volumetric muscle loss and to test experimental treatments, such as the implantation of acellular scaffolds, which promote de novo myogenesis and angiogenesis. Here we provide step-by-step instructions to perform full-thickness surgical ablation, using biopsy punches, and to remove a large volume of the tibialis anterior muscle of the lower limb in mice. This procedure results in a reduction in muscle mass and limited regeneration capacity; the approach is easy to reproduce and can also be applied to larger animal models. For therapeutic applications, we further explain how to implant bioscaffolds into the ablated muscle site. With adequate training and practice, the surgical procedure can be performed within 30 min.

Cell Mediated Reactions Create TGF-β Delivery Limitations in Engineered Cartilage

During native cartilage development, endogenous TGF-β activity is tightly regulated by cell-mediated chemical reactions in the extracellular milieu (e.g., matrix and receptor binding), providing spatiotemporal control in a manner that is localized and short acting. These regulatory paradigms appear to be at odds with TGF-β delivery needs in tissue engineering (TE) where administered TGF-β is required to transport long distances or reside in tissues for extended durations. In this study, we perform a novel examination of the influence of cell-mediated reactions on the spatiotemporal distribution of administered TGF-β in cartilage TE applications. Reaction rates of TGF-β binding to cell-deposited ECM and TGF-β internalization by cell receptors are experimentally characterized in bovine chondrocyte-seeded tissue constructs. TGF-β binding to the construct ECM exhibits non-linear Brunauer–Emmett–Teller (BET) adsorption behavior, indicating that as many as seven TGF-β molecules can aggregate at a binding site. Cell-mediated TGF-β internalization rates exhibit a biphasic trend, following a Michaelis-Menten relation (Vmax=2.4 molecules cell-1 s-1, Km=1.7 ng mL-1) at low ligand doses (≤130ng/mL), but exhibit an unanticipated non-saturating power trend at higher doses (≥130ng/mL). Computational models are developed to illustrate the influence of these reactions on TGF-β spatiotemporal delivery profiles for conventional TGF-β administration platforms. For TGF-β delivery via supplementation in culture medium, these reactions give rise to pronounced steady state TGF-β spatial gradients; TGF-β concentration decays by ∼90% at a depth of only 500 μm from the media-exposed surface. For TGF-β delivery via heparin-conjugated affinity scaffolds, cell mediated internalization reactions significantly reduce the TGF-β scaffold retention time (160 to 360-fold reduction) relative to acellular heparin scaffolds. This work establishes the significant limitations that cell-mediated chemical reactions engender for TGF-β delivery and highlights the need for novel delivery platforms that account for these reactions to achieve optimal TGF-β exposure profiles. Statement of SignificanceDuring native cartilage development, endogenous TGF-β activity is tightly regulated by cell-mediated chemical reactions in the extracellular milieu (e.g., matrix and receptor binding), providing spatiotemporal control in a manner that is localized and short acting. However, the effect of these reactions on the delivery of exogenous TGF-β to engineered cartilage tissues remains not well understood. In this study, we demonstrate that cell-mediated reactions significantly restrict the delivery of TGF-β to cells in engineered cartilage tissue constructs. For delivery via media supplementation, reactions significantly limit TGF-β penetration into constructs. For delivery via scaffold loading, reactions significantly limit TGF-β residence time in constructs. Overall, these results illustrate the impact of cell-mediated chemical reaction on TGF-β delivery profiles and support the importance of accounting for these reactions when designing TGF-β delivery platforms for promoting cartilage regeneration.

Evaluation of Bi-layer Silk Fibroin Grafts for Inlay Vaginoplasty in a Rat Model.

Autologous tissues derived from bowel, buccal mucosa and skin are primarily used to repair or replace diseased vaginal segments as well as create neovaginas for male-to-female transgenders. These grafts are often limited by scarce tissue supply, donor site morbidity and post-operative complications. Bi-layer silk fibroin (BLSF) biomaterials represent potential alternatives for vaginoplasty given their structural strength and elasticity, low immunogenicity, and processing flexibility. The goals of the current study were to assess the potential of acellular BLSF scaffolds for vaginal tissue regeneration in respect to conventional small intestinal submucosal (SIS) matrices in a rat model of vaginoplasty. Inlay vaginoplasty was performed with BLSF and SIS scaffolds (N = 21 per graft) in adult female rats for up to 2months of implantation. Nonsurgical controls (N = 4) were investigated in parallel. Outcome analyses included histologic, immunohistochemical and histomorphometric evaluations of wound healing patterns; µ-computed tomography (CT) of vaginal continuity; and breeding assessments. Animals in both scaffold cohorts exhibited 100% survival rates with no severe post-operative complications. At 2months post-op, µ-CT analysis revealed normal vaginal anatomy and continuity in both graft groups similar to controls. In parallel, BLSF and SIS grafts also induced comparable constructive remodeling patterns and were histologically equivalent in their ability to support formation of vascularized vaginal neotissues with native tissue architecture, however with significantly less smooth muscle content. Vaginal tissues reconstructed with both implants were capable of supporting copulation, pregnancy and similar amounts of live births. BLSF biomaterials represent potential "off-the-shelf" candidates for vaginoplasty.

A Nontoxic and Biocompatible Method for Augmenting Mechanical Strength of Acellular Matrix by Silk Fibroin Impregnation.

Biological scaffolds are plagued by poor biomechanical properties and untimely degradation. These limitations have yet to be addressed without compromising their biocompatibility. It is desirable to avoid inflammation and have degradation with concomitant host collagen deposition or even site-appropriate in situ regeneration for the successful outcome of an implanted biological scaffold. This work aims to achieve this by utilizing a biocompatible method to modify acellular scaffolds by impregnating alkaline-catalyzed citric acid (CA) cross-linking between the extracellular matrix proteins and silk fibroin (SF)/SF-gelatin (SFG) blends. Combinatorial detergent decellularization was employed to prepare a decellularized porcine liver scaffold (DPL). After proving the decellularization efficiency, the scaffold underwent modification by vacuum impregnation with CA containing SF (SF100DPL) and SFG blends (SFG5050DPL and SFG3070DPL) following pre-cross-linking, drying, and post-cross-linking. The subsequent strength augmentation was demonstrated by significant improvement in tensile strength from 2.4 ± 0.4 MPa (DPL) to, 3.8 ± 0.7 MPa (SF100DPL), 3.4 ± 0.7 MPa (SFG5050DPL), and 3.5 ± 0.2 MPa (SFG3070DPL); Young's modulus from 8.7 ± 1.8 MPa (DPL) to 20 ± 1.9 MPa (SF100DPL), 13.3 ± 2.6 MPa (SFG5050DPL), and 16 ± 1.2 MPa (SFG3070DPL); and suture retention strength from 0.9 ± 0.08 MPa (DPL) to 2.3 ± 0.2 MPa (SF100DPL), 2.8 ± 1.2 MPa (SFG5050DPL), and 2.6 ± 0.9 MPa (SFG3070DPL). The degradation resistance of the modified scaffolds was also markedly improved. Being cytocompatible, its ability to incite tolerable inflammatory and immune responses was confirmed by rat subcutaneous implantation for 14, 30, and 90 days, in terms of inflammatory cell infiltration, neoangiogenesis, and in vitro cytokine release to assess B-cell and T-cell activation. Such ECM composite scaffolds with appropriate strength and biocompatibility offer great promise in soft tissue repair applications such as skin grafting.

Sclerostin Antibody-Loaded Dense Collagen Hydrogels Promote Critical-Size Bone Defect Repair.

The management of extensive bone loss remains a clinical challenge. Numerous studies are underway to develop a combination of biomaterials, biomolecules, and stem cells to address this challenge. In particular, the systemic administration of antibodies against sclerostin, a regulator of bone formation, was recently shown to enhance the bone repair efficiency of dense collagen hydrogels (DCHs) hosting murine dental pulp stem cells (mDPSCs). The aim of the present study was to assess whether these antibodies, encapsulated and released from DCHs, could promote craniofacial bone repair by the local inhibition of sclerostin. In vitro studies showed that antibody loading modified neither the hydrogel structure nor the viability of seeded mDPSCs. When implanted in a mouse calvaria critical-size bone defect, antibody-loaded DCHs showed repair capabilities similar to those of acellular unloaded DCHs combined with antibody injections. Importantly, the addition of mDPSCs provided no further benefit. Altogether, the local delivery of antisclerostin antibodies from acellular dense collagen scaffolds is highly effective for bone repair. The drastic reduction in the required amount of antibody compared to systemic injection should reduce the cost of the procedure, making the strategy proposed here a promising therapeutic approach for large bone defect repair.

Construction of tissue engineered cornea with skin-derived corneal endothelial-like cell and mechanism research for the cell differentiation.

Corneal endothelial transplantation accounts for most of corneal transplantation for treating corneal diseases, however severe shortage of corneal donors is the biggest obstacle. In our previous study, we differentiated human skin-derived precursors (SKPs) into corneal endothelial cell (CEC)-like cells with a co-culture system. In this study, we aimed to investigate cell differentiation molecular mechanism and evaluate the function of CEC-like cells by developing tissue-engineered corneas in order to improve cell production efficiency and provide basic research for clinical transformation. We performed transcriptome sequencing of SKPs and CEC-like cells. Further, we focused on the possible enriching pathways, including PI3K/Akt, MAPK/Erk, WNT/β-catenin, and important transcription factors Pitx2 and Foxc1. The PI3K and β-catenin inhibitors were also added to the culture system to observe the differentiation alteration. We developed a graft for a tissue-engineered cornea (TEC) using CEC-like cells and acellular porcine cornea matrix scaffold. The tissue-engineered corneas were transplanted into rabbits via penetrating keratoplasty. The PI3K/Akt, MAPK/Erk, and WNT/β-catenin pathways play important roles during the differentiation of SKPs into CEC-like cells. Crosstalk existed between the PI3K/Akt and MAPK/Erk pathways. The PI3K/Akt and WNT/β-catenin pathways were connected. Pitx2 and Foxc1 were subject to temporal and spatial controls of the WNT/β-catenin pathway. The inhibition of the PI3K/Akt and WNT/β-catenin pathways both prevented cell differentiation. CEC-like cells grew well on the acellular porcine cornea matrix scaffold, and the tissue-engineered corneal graft performed well after transplantation into rabbits. We provide experimental basis for CEC-like cell industrial production and drive the cells to be clinically applied in cellular replacement therapy or alternative graft substitution for treating corneal diseases in the future.

The effect of acellular scaffold loaded with Wharton's jelly-derived stem cells and mineral pitch on healing of burn model in rat.

Severe burns often result in an exacerbated inflammatory response, which can contribute to further injury. This inflammatory response may lead to an increased risk of infection, multiple organ failure, and death. This study aimed to investigate the potential of reducing inflammation to enhance burn wound healing in rats using ovine's small intestinal submucosa as a carrier for Wharton's jelly mesenchymal stem cells (WJ-MSCs) and Mineral Pitch (MP). A rat burn model was developed, and the animals were divided into four groups: control group: burn, placebo group: scaffold-treated burn, cell experimental group: WJ-MSCs seeded scaffold-treated burn, and cell and MP experimental group: scaffolds loaded with WJ-MSCs and MP-treated burn. After treating the wounds in the relevant groups and sampling them on days 5, 14 and 21, histological and pathological parameters, and the expression of genes involved in angiogenesis and epithelialization were evaluated. The study results revealed several findings in the burn wounds. These included changes in mast cell populations, a decrease in inflammatory neutrophils and lymphocytes, an increase in fibroblasts and blood vessels, and upregulation of angiogenesis and epithelialization genes. These changes collectively contributed to enhanced wound healing in cell and MP experimental group compared to the other groups. The findings suggest that scaffolds loaded with Wharton's jelly-derived stem cells and MP can serve as engineered tools to modulate inflammatory conditions during the burn wound healing process. These interventions can improve burn wound management and promote better outcomes.

Integrin-β1 aggravates paraquat-induced pulmonary fibrosis by activation of FAK/ ERK1/2 pathway depending on fibrotic ECM

BackgroundIrreversible pulmonary fibrosis induced by paraquat is the most prevalent cause of death in patients with paraquat poisoning. Pulmonary fibrosis is characterized by abnormal deposition of extracellular matrix (ECM). Currently, the role of fibrotic ECM microenvironment in paraquat-induced pulmonary fibrosis has not been established. MethodsRat pulmonary fibrosis model was induced by paraquat, ATN-161 (an integrin-β1 antagonist) was given to investigate their effect on Rat survival and pulmonary fibrosis. Lungs were decellularized to generate normal and fibrotic acellular ECM scaffolds using Triton and SDS. Fibroblasts were cocultured with ECM scaffolds to established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts. Then we explored the effect of fibrotic ECM microenvironment systematically promoting on integrin-β1/FAK/ERK1/2 pathway and established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts. ResultsAntagonism of integrin-β1 could alleviate paraquat-induced pulmonary fibrosis and ameliorate survival status of rats. Compared to normal ECM, fibrotic extracellular microenvironment promoted the differentiation of fibroblasts to myofibroblasts. Antagonism of integrin-β1 could also ameliorate the promotion of fibrotic extracellular microenvironment on differentiation of fibroblasts to myofibroblasts. Fibrotic ECM microenvironment promotes fibroblasts transforming into myofibroblasts through integrin-β1/FAK/ERK1/2 signaling pathway. Moreover, this phenomenon holds independent on exogenous integrin-β1. ConclusionsActivation of integrin-β1/FAK/ERK1/2 pathway aggravates paraquat-induced pulmonary fibrosis depend on fibrotic ECM and integrin-β1 may be a prospective therapeutic target for paraquat-induced pulmonary fibrosis in the future.

The search for an optimal tissue-engineered urethra model for clinical application based on preclinical trials in male animals: A systematic review and meta-analysis.

Tissue engineering has emerged as a promising avenue for reconstructive urology, though only a limited number of tissue-engineered urethral constructs have advanced to clinical testing. Presently, there exists a dearth of agreement regarding the most promising constructs deserving of implementation in clinical practice. The objective of this review was to provide a comprehensive analysis of preclinical trials findings of a tissue-engineered urethra and to identify the most promising constructs for future translation into clinical practice. A systematic search of the Pubmed, Scopus, and PMC databases was conducted in accordance with the PRISMA statement. Manuscripts published in English between 2015 and 2022, reporting on the methodology for creating a tissue-engineered urethra, assessing the regenerative potential of the scaffold in a male animal model, and evaluating the clinical and histological outcomes of treatment, were included. A total of 48 manuscripts met the inclusion criteria, with 12 being eligible for meta-analysis. Meta-analysis revealed no significant benefit of any matrix type in terms of complication rates. However, acellular matrices demonstrated significant advantage over cellular matrices in case of no postoperative stricture formation (odds ratio = 0.06 [95% CI 0.01; 0.23], p < 0.01). Among all subgroups (animal models and scaffold types), the usage of acellular matrices resulted in advantageous effects. The meta-regression analysis did not show a significant impact of defect length (β1 = -0.02 [-0.28; 0.23], p = 0.86). We found that decellularized materials may carry less relevance for urethral reconstruction due to unfavorable preclinical outcomes. Natural polymers, used independently or with synthetic materials, resulted in better postoperative outcomes in animals compared to purely synthetic constructs. Acellular scaffolds showed promising outcomes, matching or exceeding cellular constructs. However, more studies are needed to confirm their clinical effectiveness.

Exosomes from Hypoxia Preconditioned Muscle-Derived Stem Cells Enhance Cell-Free Corpus Cavernosa Angiogenesis and Reproductive Function Recovery.

Tissue engineering for penile corpora cavernosa defects requires microvascular system reconstruction.GelMA hydrogels show promise for tissue regeneration. However, using stem cells faces challenges such as immune rejection, limited proliferation and differentiation, and biosafety concerns. Therefore, acellular tissue regeneration may avoid these issues. Exosomes are used from muscle-derived stem cells (MDSCs) to modify 3D-printed hydrogel scaffolds for acellular tissue regeneration. Hypoxia-preconditioned MDSC-derived exosomes are obtained to enhance the therapeutic effect. In contrast to normoxic exosomes (N-Exos), hypoxic exosomes (H-Exos) are found to markedly enhance the proliferation, migration, and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). High-throughput sequencing analysis of miRNAs isolated from both N-Exos and H-Exos revealed a significant upregulation of miR-21-5p in H-Exos following hypoxic preconditioning. Further validation demonstrated that the miR-21-5p/PDCD4 pathway promoted the proliferation of HUVECs. Epigallocatechin gallate (EGCG) is introduced to improve the mechanical properties and biocompatibility of GelMA hydrogels. EGCG-GelMA scaffolds loaded with different types of Exos are transplanted to repair rabbit penile corpora cavernosa defects, observed the blood flow and repair status of the defect site through color Doppler ultrasound and magnetic resonance imaging, and ultimately restored the rabbit penile erection function and successfully bred offspring. Thus, acellular hydrogel scaffolds offer an effective treatment for penile corpora cavernosa defects.

WED-102 Transplanted acellular liver scaffold is not affected by the cirrhotic liver remaining a healthy template for cell growth

WED-102 Transplanted acellular liver scaffold is not affected by the cirrhotic liver remaining a healthy template for cell growth

Novel Treatment Options for Knee Cartilage Defects in 2023.

Articular cartilage lesions are a common injury that have become increasingly treatable with joint preservation procedures. Well-documented allograft and cellular treatments for these lesions are detailed elsewhere in this volume. This article discusses three new unique options for addressing these defects taking three different paths to address these complex injuries. Agili-C is an existing FDA- and EMEA-approved option using an acellular aragonite-based scaffold to treat both chondral and osteochondral lesions, with or without concurrent arthritis. Cartistem is a stem-cell-based product composed of culture-expanded allogeneic human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel, which is in its final clinical trial stages in the United States, but already has regulatory approval in Korea. IMPACT and RECLAIM studies have shown the safety and efficacy of a new one-stage procedure utilizing autologous chondrons combined with allogeneic mesenchymal stem cells (MSCs) that can provide another effective single-stage treatment option.

Acellular spinal cord scaffold containing quercetin-encapsulated nanoparticles plays an anti-inflammatory role in functional recovery from spinal cord injury in rats.

Inflammatory responses play a crucial role in the pathophysiology of spinal cord injury (SCI) and developing new approaches to establish an anti-inflammatory environment for the promotion of neuroregeneration holds promise as a potential approach. In this study, our aim was to investigate the potential of combining an acellular spinal cord scaffold (ASCS) with quercetin-loaded bovine serum albumin (Qu/BSA) nanoparticles (NPs) for the treatment of SCI. The ASCS was prepared using physical and chemical methods, while the Qu/BSA NPs were prepared through a desolvation technique. The NPs exhibited favorable characteristics, including a mean size of 203nm, a zeta potential of -38, and an encapsulation efficiency of 96%. Microscopic evaluation confirmed the successful distribution of NPs on the walls of ASCS. Animal studies revealed that Qu/BSA NPs group exhibited a significant decrease in NLRP3, ASC, and Casp1 gene expression compared to the SCI group (p < 0.0001). The findings indicated a significant decrease in the NLRP3, ASC, and Casp1 protein level between the Qu/BSA/ASCS group and the SCI group (p < 0.0001). Moreover, treatment with ASCS containing either blank BSA (B/BSA) NPs or Qu/BSA NPs effectively promoted functional recovery via increasing the amount of nestin- and glial fibrillary acidic protein (GFAP)-positive cells in the site of injury. Notably, Qu/BSA/ASCS exhibited superior outcomes compared to B/BSA/ASCS. Overall, the combination of ASCS with the Qu delivery system presents a promising therapeutic approach for SCI by inhibiting inflammatory responses and promoting neuroregeneration, leading to the restoration of motor function in animals. This study demonstrates the potential of utilizing biomaterials and NPs to enhance the effectiveness of SCI treatment.

Anisotropic hydrogel scaffold by flow-induced stereolithography 3D printing technique

Essential organs, such as the heart and liver, contain a unique porous network that allows oxygen and nutrients to be exchanged, with distinct random to ordered regions displaying varying degrees of strength. A novel technique, referred to here as flow-induced lithography, was developed. This technique generates tunable anisotropic three-dimensional (3D) structures. The ink for this bioprinting technique was made of titanium dioxide nanorods (Ti) and kaolinite nanoclay (KLT) dispersed in a GelMA/PEGDA polymeric suspension. By controlling the flow rate, aligned particle microstructures were achieved in the suspensions. The application of UV light to trigger the polymerization of the photoactive prepolymer freezes the oriented particles in the polymer network. Because the viability test was successful in shearing suspensions containing cells, the flow-induced lithography technique can be used with both acellular scaffolds and cell-laden structures. Fabricated hydrogels show outstanding mechanical properties resembling human tissues, as well as significant cell viability (> 95 %) over one week. As a result of this technique and the introduction of bio-ink, a novel approach has been pioneered for developing anisotropic tissue implants utilizing low-viscosity biomaterials.

Regenerative Medicine in Urogynecology: Where We Are and Where We Want to Be.

Pelvic floor disorders (PFDs) constitute a major public health issue given their negative effect on quality of life for millions of women worldwide and the associated economic burden. As the prevalence of PFDs continues to increase, novel therapeutic approaches for the effective treatment of these disorders are urgently needed. Regenerative medicine techniques, including cellular therapies, extracellular vesicles, secretomes, platelet-rich plasma, laser therapy, and bioinductive acellular biomaterial scaffolds, are emerging as viable clinical options to counteract urinary and fecal incontinence, as well as pelvic organ prolapse. This brief expert review explores the current state-of-science regarding application of these therapies for the treatment of PFDs. Although regenerative approaches have not been widely deployed in clinical care to date, these innovative techniques show a promising safety profile and potential to positively affect the quality of life of patients with PFDs. Furthermore, investigations focused on regeneration of the main constituents of the pelvic floor and lower urinary tract improve our understanding of the underlying pathophysiology of PFDs. Regenerative medicine techniques have a high potential not only to revolutionize treatment of PFDs but also to prevent these complex conditions.

The extracellular matrix protein fibronectin promotes metanephric kidney development

Complex interactions of the branching ureteric bud (UB) and surrounding mesenchymal cells during metanephric kidney development determine the final number of nephrons. Impaired nephron endowment predisposes to arterial hypertension and chronic kidney disease. In the kidney, extracellular matrix (ECM) proteins are usually regarded as acellular scaffolds or as the common histological end-point of chronic kidney diseases. Since only little is known about their physiological role in kidney development, we aimed for analyzing the expression and role of fibronectin. In mouse, fibronectin was expressed during all stages of kidney development with significant changes over time. At embryonic day (E) 12.5 and E13.5, fibronectin lined the UB epithelium, which became less pronounced at E16.5 and then switched to a glomerular expression in the postnatal and adult kidneys. Similar results were obtained in human kidneys. Deletion of fibronectin at E13.5 in cultured metanephric mouse kidneys resulted in reduced kidney sizes and impaired glomerulogenesis following reduced cell proliferation and branching of the UB epithelium. Fibronectin colocalized with alpha 8 integrin and fibronectin loss caused a reduction in alpha 8 integrin expression, release of glial-derived neurotrophic factor and expression of Wnt11, both of which are promoters of UB branching. In conclusion, the ECM protein fibronectin acts as a regulator of kidney development and is a determinant of the final nephron number.