Tissue Engineering Approaches Research Articles

Advanced Therapeutic Medicinal Products in Bone and Cartilage Defects.

The number of patients with functional loss of bone and cartilage tissue has shown an increasing trend. Insufficient or inappropriate conventional treatments applied for trauma, orthopedic diseases, or other bone and cartilage-related disorders can lead to bone and cartilage damage. This represents a worldwide public health issue and a significant economic burden. Advanced therapeutic medicinal products (ATMPs) proposed promising alternative therapeutic modalities by application of cell-based and tissue engineering approaches. Recently, several ATMPs have been developed to promote bone and cartilage tissue regeneration. Fifteen ATMPs, two related to bone and 13 related to cartilage, have received regulatory approval and marketing authorization. However, four ATMPs were withdrawn from the market for various reasons. However, ATMPs that are still on the market have demonstrated positive results, their broad application faced limitations. The development and standardization of methodologies will be a major challenge in the coming decades. Currently, the number of ATMPs in clinical trials using mesenchymal stromal cells or chondrocytes indicates a growing recognition that current ATMPs can be improved. Research on bone and cartilage tissue regeneration continues to expand. Cell-based therapies are likely to be clinically supported by the new ATMPs, innovative fabrication processes, and enhanced surgical approaches. In this study, we highlighted the available ATMPs that have been used in bone and cartilage defects and discussed their advantages and disadvantages in clinical applications.

Healthy but not osteoarthritic human meniscus-derived matrix scaffolds promote meniscus repair

Meniscus tissue is commonly injured due to sports-related injuries and age-related degeneration and approximately 50% of individuals with a meniscus tear will develop post-traumatic osteoarthritis (PTOA). Given that the meniscus has limited healing potential, new therapeutic strategies are required to enhance meniscus repair. Porcine meniscus-derived matrix (MDM) scaffolds improve meniscus integrative repair, but sources of human meniscus tissue have not been investigated. Therefore, the objectives of this study were to generate healthy and osteoarthritic (OA) MDM scaffolds and to compare meniscus cellular responses and integrative repair. Meniscus cells showed high viability on both healthy and OA scaffolds. While DNA content was higher in cell-seeded OA scaffolds than cell-seeded healthy scaffolds, CCK-8, and both sGAG and collagen content were similar between scaffold types. After 28 days in an ex vivo meniscus defect model, healthy and OA scaffolds had similar DNA, sGAG, and collagen content. However, the shear strength of repair was reduced in defects containing OA scaffolds compared to healthy scaffolds. In conclusion, healthy human allograft tissue is a useful source for generating MDM scaffolds that can support cellular growth, ECM production, and ex vivo integrative repair of the meniscus, highlighting the potential suitability for tissue engineering approaches to improve meniscus repair.

Silver-Treated Silk Fibroin Scaffolds for Prevention of Critical Wound Infections

The risk of infections in chronic wounds represents a serious issue, particularly in aged people and in patients affected by diseases such as diabetes and obesity. Moreover, the growing resistance demonstrated by many bacterial strains has significantly reduced the therapeutic options for clinicians and has become a great challenge for the researchers in the definition of novel approaches that promote the wound healing process and reduce the healing time. Tissue engineering approaches based on biomaterials and three-dimensional scaffolds have demonstrated huge potential in supporting cell proliferation; among them, Bombyx mori-derived silk fibroin is a very appealing possibility for the development of devices with regenerative properties for wound healing applications. However, due to the high risk of infections in chronic wounds, an antibacterial treatment is also strongly encouraged for preventing bacterial proliferation at the wound site. In this work, to develop a device with regenerative and antibacterial properties, antibacterial silver coatings were deposited onto silk fibroin scaffolds, and the effect of the treatment in terms of chemical–physical and microbiological properties was investigated. The results demonstrated that the silver treatment improved the mechanical properties of the protein scaffold and provided good antibacterial efficacy against representative bacterial strains in wound infection, namely Escherichia coli and antibiotic-resistant Pseudomonas aeruginosa.

Investigating Inherited Heart Diseases Using Human Induced Pluripotent Stem Cell-Based Models

Inherited heart diseases (IHDs) are caused by genetic mutations that disrupt the physiological structure and function of the heart. Understanding the mechanisms behind these diseases is crucial for developing personalised interventions in cardiovascular medicine. Development of induced pluripotent stem cells, which can then be differentiated to any nucleated adult cell type, has enabled the creation of personalised single-cell and multicellular models, providing unprecedented insights into the pathophysiology of IHDs. This review provides a comprehensive overview of recent advancements in human iPSC models used to dissect the molecular and genetic underpinnings of common IHDs. We examine multicellular models and tissue engineering approaches, such as cardiac organoids, engineered heart tissue, and multicellular co-culture systems, which simulate complex intercellular interactions within heart tissue. Recent advancements in stem cell models offer a more physiologically relevant platform to study disease mechanisms, enabling researchers to observe cellular interactions, study disease progression, and identify therapeutic strategies. By leveraging these innovative models, we can gain deeper insights into the molecular and cellular mechanisms underlying IHDs, ultimately paving the way for more effective diagnostic and therapeutic strategies.

Enhanced Myogenic Differentiation of Human Adipose‐Derived Stem Cells via Integration of 3D Bioprinting and In Situ Shear‐Based Blade Coating

AbstractConventional treatments for volumetric muscle loss (VML) encounter limitations, such as donor site constraints and exploration of tissue engineering methods. Here, the fabrication of human adipose stem cell (hASC)‐laden cell constructs are proposed using a 3D bioprinting technique supported by blade casting. This process induces mechanotransduction to activate stem cell activities, including proliferation and myogenic differentiation. The printing conditions are optimized by assessing the effects of various process parameters on mechanotransduction signaling pathways. Notably, blade‐assisted bioprinting under carefully selected parameters enhanced the in vitro myogenic activity of the fabricated hASC constructs. Moreover, in vivo evaluation in mice with VML defects demonstrate that shear‐induced bioconstructs effectively restored lost functionalities and muscle volume compared to those of normally bioprinted cell constructs. The results show the potential of integrating bioprinting with hASC‐based therapies to enhance muscle regeneration and functional recovery, offering a meaningful platform for future tissue engineering approaches for VML treatment.

Current advances in the development of microRNA-integrated tissue engineering strategies: a cornerstone of regenerative medicine.

Regenerative medicine is an innovative scientific field focused on repairing, replacing, or regenerating damaged tissues and organs to restore their normal functions. A central aspect of this research arena relies on the use of tissue-engineered scaffolds, which serve as structural supports that mimic the extracellular matrix, providing an environment that orchestrates cell growth and tissue formation. Remarkably, the therapeutic efficacy of these scaffolds can be improved by harnessing the properties of other molecules or compounds that have crucial roles in healing and regeneration pathways, such as phytochemicals, enzymes, transcription factors, and non-coding RNAs (ncRNAs). In particular, microRNAs (miRNAs) are a class of tiny (20-24nt), highly conserved ncRNAs that play a critical role in the regulation of gene expression at the post-transcriptional level. Accordingly, miRNAs are involved in a myriad of biological processes, including cell differentiation, proliferation, and apoptosis, as well as tissue regeneration, angiogenesis, and osteogenesis. On this basis, over the past years, a number of research studies have demonstrated that miRNAs can be integrated into tissue-engineered scaffolds to create advanced therapeutic platforms that precisely modulate cellular behavior and offer a controlled and targeted release of miRNAs to optimize tissue repair and regeneration. Therefore, in this current review, we discuss the most recent advances in the development of miRNA-loaded tissue-engineered scaffolds and provide an overview of the future outlooks that should be aborded in this area of study in order to lay the groundwork for the clinical translation of these tissue engineering approaches.

Exosome-Laden Hydrogels as Promising Carriers for Oral and Bone Tissue Engineering: Insight into Cell-Free Drug Delivery.

Mineralization is a key biological process that is required for the development and repair of tissues such as teeth, bone and cartilage. Exosomes (Exo) are a subset of extracellular vesicles (~50-150 nm) that are secreted by cells and contain genetic material, proteins, lipids, nucleic acids, and other biological substances that have been extensively researched for bone and oral tissue regeneration. However, Exo-free biomaterials or exosome treatments exhibit poor bioavailability and lack controlled release mechanisms at the target site during tissue regeneration. By encapsulating the Exos into biomaterials like hydrogels, these disadvantages can be mitigated. Several tissue engineering approaches, such as those for wound healing processes in diabetes mellitus, treatment of osteoarthritis (OA) and cartilage degeneration, repair of intervertebral disc degeneration, and cardiovascular diseases, etc., have been exploited to deliver exosomes containing a variety of therapeutic and diagnostic cargos to target tissues. Despite the significant efficacy of Exo-laden hydrogels, their use in mineralized tissues, such as oral and bone tissue, is very sparse. This review aims to explore and summarize the literature related to the therapeutic potential of hydrogel-encapsulated exosomes for bone and oral tissue engineering and provides insight and practical procedures for the development of future clinical techniques.

Injectable Janus Base Nanomatrix (JBNm) in Maintaining Long-Term Homeostasis of Regenerated Cartilage for Tissue Chip Applications.

Engineered cartilage tissues have wide applications in in vivo cartilage repair as well as in vitro models, such as cartilage-on-a-chip or cartilage tissue chips. Currently, most cartilage tissue engineering approaches focus on promoting chondrogenesis of stem cells to produce regenerated cartilage. However, this regenerated cartilage can dedifferentiate into fibrotic tissue or further differentiate into hypertrophic or calcified cartilage. One of the most challenging objectives in cartilage tissue engineering is to maintain long-term cartilage homeostasis. Since the microenvironment of engineered cartilage tissue is crucial for stem cell adhesion, proliferation, differentiation, and function, we aim to develop a novel scaffold that can maintain the long-term homeostasis of regenerated cartilage. Therefore, we developed a library of Janus base nanomatrices (JBNms), composed of DNA-inspired Janus nanotubes (JBNts) as well as cartilage extracellular matrix (ECM) proteins. The JBNms were developed to selectively promote chondro-lineage cell functions while inhibiting bone and endothelial cell growth. More importantly, the JBNm can effectively promote chondrogenesis while inhibiting hypertrophy, osteogenesis, angiogenesis, and dedifferentiation. Additionally, the JBNm is injectable, forming a solid scaffold suitable for producing and maintaining regenerated cartilage tissue in microfluidic chips, making it ideal for tissue chip applications. In this study, we successfully created cartilage tissue chips using JBNms. These chips can model cartilage tissue even after long-term culture and can also mimic arthritis progression, making them useful for drug screening. Thus, we have developed a novel nanomaterial approach for improved cartilage tissue engineering and cartilage tissue chip applications.

Leveraging in vivo animal models of tendon loading to inform tissue engineering approaches.

Tendon injuries disrupt successful transmission of force between muscle and bone, resulting in reduced mobility, increased pain, and significantly reduced quality of life for affected patients. There are currently no targeted treatments to improve tendon healing beyond conservative methods such as rest and physical therapy. Tissue engineering approaches hold great promise for designing instructive biomaterials that could improve tendon healing or for generating replacement graft tissue. More recently, engineered microphysiological systems to model tendon injuries have been used to identify therapeutic targets. Despite these advances, current tissue engineering efforts that aim to regenerate, replace, or model injured tendons have largely failed due in large part to a lack of understanding of how the mechanical environment of the tendon influences tissue homeostasis and how altered mechanical loading can promote or prevent disease progression. This review article draws inspiration from what is known about tendon loading from in vivo animal models and identifies key metrics that can be used to benchmark success in tissue engineering applications. Finally, we highlight important challenges and opportunities for the field of tendon tissue engineering that should be taken into consideration in designing engineered platforms to understand or improve tendon healing.

Engineered Tendon-Fibrocartilage-Bone Composite With Mechanical Stimulation for Augmentation of Rotator Cuff Repair: A Study Using an In Vivo Canine Model With a 6-Month Follow-up.

Rotator cuff repair augmentation using biological materials has become popular in clinical practice to reduce the high retear rates associated with traditional repair techniques. Tissue engineering approaches, such as engineered tendon-fibrocartilage-bone composite (TFBC), have shown promise in enhancing the biological healing of rotator cuff tears in animals. However, previous studies have provided limited long-term data on TFBC repair outcomes. The effect of mechanical stimulation on TFBC has not been explored extensively. To evaluate functional outcomes after rotator cuff repair with engineered TFBC subjected to mechanical stimulation in a 6-month follow-up using a canine in vivo model. Controlled laboratory study. A total of 40 canines with an acute infraspinatus (ISP) tendon transection model were randomly allocated to 4 groups (n =10): (1) unilateral ISP tendon undergoing suture repair only (control surgery); (2) augmentation with engineered TFBC alone (TFBC); (3) augmentation with engineered TFBC and bone marrow-derived stem cells (BMSCs) (TFBC+C); and (4) augmentation with engineered TFBC and BMSCs, as well as mechanical stimulation (TFBC+C+M). Outcome measures-including biomechanical evaluations such as failure strength, stiffness, failure mode, gross appearance, ISP tendon and muscle morphological assessment, and histological analysis-were performed 6 months after surgery. As shown in the mechanical test, the TFBC+C+M group exhibited higher failure strength compared with other repair techniques. The most common failure mode was avulsion fracture in the TFBC+C+M group, but tendon-bone junction rupture was observed predominantly in different groups. Engineered TFBC with mechanical stimulation showed over 70% relative failure strength compared with normal ISP, and the other groups showed about 50% relative failure strength. Histological analysis revealed less fat infiltration and closer-to-normal muscle fiber structure in the mechanical stimulation group. This study provides evidence that mechanical stimulation of engineered TFBC promotes rotator cuff regeneration, thus supporting its potential for rotator cuff repair augmentation. This study provides valuable evidence supporting the use of a novel tissue-engineered material (TFBC) in rotator cuff repair and paves the way for advancements in the field of rotator cuff regeneration.

Establishing a rabbit model with massive supraspinatus tendon defect for investigating scaffold-assisted tendon repair

BackgroundShoulder pain and disability from rotator cuff tears remain challenging clinical problem despite advancements in surgical techniques and materials. To advance our understanding of injury progression and develop effective therapeutics using tissue engineering and regenerative medicine approaches, it is crucial to develop and utilize animal models that closely resemble the anatomy and display the pathophysiology of the human rotator cuff. Among various animal models, the rabbit shoulder defect model is particularly favored due to its similarity to human rotator cuff pathology. However, a standardized protocol for creating a massive rotator cuff defect in the rabbits is not well defined. Therefore, the objective of our study was to establish a robust and reproducible model of a rotator cuff defect to evaluate the regenerative efficacy of scaffolds.ResultsIn our study, we successfully developed a rabbit model with a massive supraspinatus tendon defect that closely resembles the common rotator cuff injuries observed in humans. This defect involved a complete transection of the tendon, spanning 10 mm in length and encompassing its full thickness and width. To ensure stable scaffolding, we employed an innovative bridging suture technique that utilized a modified Mason-Allen suture as a structural support. Moreover, to assess the therapeutic effectiveness of the model, we utilized different scaffolds, including a bovine tendon extracellular matrix (ECM) scaffold and a commercial acellular dermal matrix (ADM) scaffold. Throughout the observation period, no scaffold damage was observed. Notably, comprehensive histological analysis demonstrated that the regenerative tissue in the tendon ECM scaffold group exhibited an organized and aligned fiber structure, indicating tendon-like tissue regeneration while the tissue in the ADM group showed comparatively less organization.ConclusionsThis study presents a comprehensive description of the implemented procedures for the development of a highly reproducible animal model that induces massive segmental defects in rotator cuff tendons. This protocol can be universally implemented with alternative scaffolds to investigate extensive tendon defects and evaluate the efficacy of regenerative treatments. The application of our animal model offers a standardized and reproducible platform, enabling researchers to systematically evaluate, compare, and optimize scaffold designs. This approach holds significant importance in advancing the development of tissue engineering strategies for effectively repairing extensive tendon defects.

Multi-parameter tunable synthetic matrix for engineering lymphatic vessels

Controlling the formation of new lymphatic vessels has been postulated as an innovative therapeutic strategy for various disease phenotypes, including neurodegenerative diseases, metabolic syndrome, cardiovascular disease, and lymphedema. Yet, compared to the blood vascular system, little is known about the molecular regulation that controls lymphatic tube formation in a synthetic matrix. In this study, we utilize hyaluronic acid (HA)-hydrogels to design a novel platform for decoupled investigation into how mechanical and biochemical cues regulate lymphatic vessel formation in a synthetic matrix. Using HA and controlling the degree of modification provides a method to preserve and modulate key lymphatic markers Prox1, LYVE-1, and Pdpn. The chemistry of the system allows for spatial and temporal patterning of specific peptides and substrate stiffnesses, and an MMP-sensitive crosslinker allowed cells to degrade and remodel their matrix. Through systematic optimization of multiple parameters, we have designed a system that allows human lymphatic endothelial cells (LECs) to self-assemble into vessels in vitro within 3 days. These engineered vessels can be cultured for up to 3 weeks and can be used for high-throughput mechanistic studies, or can be implanted into immunodeficient mice where they have demonstrated the ability to integrate and mature. Collectively, these studies report a novel, fully-defined 3D synthetic matrix system capable of generating lymphatic vessels in vitro that provide promise as an in vitro screening platform and as a therapeutic vessel transplant, which to our knowledge, is the first ever 3D lymphatic tissue engineering approach to not require the use of support cells.

Fabrication and characterization of an electrospun silk fibroin/gelatin transparent graft material for corneal epithelial regeneration

The damaged corneal epithelial causing loss of vision can be restored by epithelial tissue regeneration through tissue engineering approach that provides an engineered corneal substitute with appropriate properties and nanofibrous architecture. This works reports a polymeric matrix that was derived from silk fibroin (SF) and gelatin (GE) natural polymer blend with optimized composition resembling the structure and function of the native epithelial tissue. SF/GE blend spinning solutions prepared with different volume ratios of SF/GE: 70/30, 50/50, and 30/70 were used to fabricate electrospun mats. The fabricated two-dimensional mats had nanofibrous porous architecture having interconnected pores with pore size range of 175–267 nm suitable for corneal epithelial regeneration and 891.2–558 nm fiber diameter range as revealed by scanning electron microscopic image analysis. The performed Fourier transform infrared spectra confirmed the presence of individual polymers in the scaffolds and the scaffolds are hydrophilic in nature. Among the scaffolds, SF/GE 70:30 and SF/GE 50:50 composition possess desired porosity range of 87–88%. The tensile strength was slightly decreased with increase in GE content and the strength obtained was in the range 2.74–2.26 Mpa. An enhanced transparency was obtained with increased GE concentration, the transparency range of 73–82% observed with SF/GE:50/50 matches with the transparency of natural corneal epithelium. The biocompatibility of the scaffolds was confirmed by cell attachment, cytotoxicity and ROS evaluation by culturing rabbit corneal fibroblast cells (SIRC) on the scaffolds. Among the scaffolds, SF/GE: 70/30 exhibited the highest cell viability, but with less transparency ranging 55–71%. Therefore, considering all the properties, SF/GE with 50:50 ratio scaffold may be a suitable substrate in the field of corneal tissue engineering.

Graphene Oxide Nano-Sheets: A Novel Eco-Friendly Approach for Tissue Engineering and Antibacterial Applications in Bone Disease

Obtaining novel scaffolds on bone disease-affected cells with osteoconductivity has recently been the focus of tissue engineering methodologies. Chemical treatment and microwave radiation form a novel strategy to create graphene oxide nanosheets (Gns) that decorate carbon crystal structures. This approach is proven to be eco-friendly. Gns was characterized using "X-ray diffraction, ultraviolet, and Fourier transform infrared spectrophotometers". The XRD spectra confirmed the crystalline structure of Gns. The Gns product was analyzed using "Raman spectroscopy. Transmission electron microscopy and field-emission scanning electron microscopy" exposed few layered surfaces of Gns. The TEM images showed Gns specifically decorated with carbon nanoparticles. The evidence demonstrated the novelty of Gns as a very effective bactericidal agent, suggesting its potential as a future antibacterial agent. Different concentrations of Gns and its derivatives showed different cell viabilities toward various cell lines, demonstrating the dependency of a biocompatible environment for good attachment on MG63 cells.

3D-printed injectable nanocomposite cryogel scaffolds for bone tissue regeneration

Cryogels are known for their high water content and interconnected macroporosity, two relevant features in tissue engineering approaches. The cryogel structure can support tissue growth as it allows nutrient and oxygen diffusion, removal of waste products, as well as an enhancement of cell infiltration and proliferation. Bioactive glass nanoparticles are biocompatible and clinically approved bioactive materials widely used as implants in the human body to repair or replace diseased or damaged bones. They are known to facilitate bone binding while stimulating bone growth. Indeed, the combination of cryogels with bioactive nanoparticles has already demonstrated promising results for bone regeneration. Although the developed biomaterials succeed in bone regeneration, they lack suitability for minimal invasive procedures or patient-specificity. Here, we demonstrate a freeform 3D printed nanocomposite cryogel, resorting to an ink composed of functionalized gelatin and bioactive glass nanoparticles with methacrylate groups. Complex structures with multiple layers were 3D printed in a xanthan gum supporting bath. The developed 3D printed nanocomposite cryogels demonstrate the ability to recover their shape without any permanent damage, withstanding up to 65 % compression upon injection. Additionally, they stimulate the differentiation of human adipose-derived stem cells into the osteoblast lineage, therefore promoting bone tissue growth. We further demonstrated their suitability for minimal invasive therapeutics by filling a reproduction of a maxillofacial defect. The developed 3D-printed nanocomposite cryogels offer robust shape-recovery properties, easy injectability, tailored geometry into patient-specific injuries, and high osteogenic bioactivity, showcasing its versatility for bone regeneration purposes.

Small Molecular Approaches for Cellular Reprogramming and Tissue Engineering: Functions as Mediators of the Cell Signaling Pathway.

Utilizing induced pluripotent stem cells (iPSCs) in drug screening and cell replacement therapy has emerged as a method with revolutionary applications. With the advent of patient-specific iPSCs and the subsequent development of cells that exhibit disease phenotypes, the focus of medication research will now shift toward the pathology of human diseases. Regular iPSCs can also be utilized to generate cells that assess the negative impacts of medications. These cells provide a much more precise and cost-efficient approach compared to many animal models. In this review, we explore the utilization of small-molecule drugs to enhance the growth of iPSCs and gain insights into the process of reprogramming. We mainly focus on the functions of small molecules in modulating different signaling pathways, thereby modulating cell fate. Understanding the way small molecule drugs interact with iPSC technology has the potential to significantly enhance the understanding of physiological pathways in stem cells and practical applications of iPSC-based therapy and screening systems, revolutionizing the treatment of diseases.

ALKBH5 Regulates Osteogenic Differentiation via the lncRNA/mRNA Complex

Human adipose-derived stem cells (hASCs) are commonly used in bone tissue regeneration. The N6-methyladenosine (m6A) modification has emerged as a novel regulatory mechanism for gene expression, playing a critical role in osteogenic differentiation of stem cells. However, the precise role and mechanism of alkylation repair homolog 5 (ALKBH5) in hASC osteogenesis remain incompletely elucidated and warrant further investigation. Herein, we employed methylated RNA immunoprecipitation sequencing, RNA sequencing, and weighted gene coexpression network analysis to identify a key long noncoding RNA (lncRNA) in hASCs: lncRNA AK311120. Functional experiments demonstrated that lnc-AK311120 promoted the osteogenic differentiation of hASCs, while a mutation at the m6A central site A of lnc-AK311120 was found to decrease the level of m6A modification. The osteogenic effect of ALKBH5 was confirmed both in vitro and in vivo using a mandibular defect model in nude mice. Subsequent investigations revealed that knockdown of ALKBH5 resulted in a significant increase in the m6A modification level of lnc-AK311120, accompanied by a downregulation in the expression level of lnc-AK311120. Additional rescue experiments demonstrated that overexpression of lnc-AK311120 could restore the phenotype after ALKBH5 knockdown. We observed that AK311120 interacted with the RNA-binding proteins DExH-Box helicase 9 (DHX9) and YTH domain containing 2 (YTHDC2) to form a ternary complex, while mitogen-activated protein kinase kinase 7 (MAP2K7) served as the shared downstream target gene of DHX9 and YTHDC2. Knockdown of AK311120 led to a reduction in the binding affinity between DHX9/YTHDC2 and the target gene MAP2K7. Furthermore, ALKBH5 facilitated the translation of MAP2K7 and activated the downstream JNK signaling pathway through the AK311120–DHX9–YTHDC2 complex, without affecting its messenger RNA level. Collectively, we have investigated the regulatory effect and mechanism of ALKBH5-mediated demethylation of lncRNA in hASC osteogenesis for the first time, offering a promising approach for bone tissue engineering.

Application of polydopamine-modified triphasic PLA/PCL-PLGA/Mg(OH)2-velvet antler polypeptides scaffold loaded with fibrocartilage stem cells for the repair of osteochondral defects.

Articular cartilage defects often involve damage to both the cartilage and subchondral bone, requiring a scaffold that can meet the unique needs of each tissue type and establish an effective barrier between the bone and cartilage. In this study, we used 3D printing technology to fabricate a tri-phasic scaffold composed of PLA/PCL-PLGA/Mg(OH)₂, which includes a cartilage layer, an osteochondral interface, and a bone layer. The scaffold was filled with Velvet antler polypeptides (VAP), and its characterization was assessed using compression testing, XRD, FTIR, SEM, fluorescence microscopy, and EDS. In vitro investigation demonstrated that the scaffold not only supported osteogenesis but also promoted chondrogenic differentiation of fibrocartilage stem cells (FCSCs). n vivo experiments showed that the tri-phasic PLA/PCL-PLGA/Mg(OH)2-VAP scaffold together with FCSC, when transplanted to animal models, increased the recovery of osteochondral defects. Those results demonstrate the promising future of illustrated tri-phasic PLA/PCL-PLGA/Mg(OH)2-VAP scaffold loaded with FCSCs as a new bone and cartilage tissue engineering approach for osteochondral defects treatment.

Composite Polycaprolactone/Gelatin Nanofiber Membrane Scaffolds for Mesothelial Cell Culture and Delivery in Mesothelium Repair.

To repair damaged mesothelium tissue, which lines internal organs and cavities, a tissue engineering approach with mesothelial cells seeded to a functional nanostructured scaffold is a promising approach. Therefore, this study explored the uses of electrospun nanofiber membrane scaffolds (NMSs) as scaffolds for mesothelial cell culture and transplantation. We fabricated a composite NMS through electrospinning by blending polycaprolactone (PCL) with gelatin. The addition of gelatin enhanced the membrane's hydrophilicity while maintaining its mechanical strength and promoted cell attachment. The in vitro study demonstrated enhanced adhesion of mesothelial cells to the scaffold with improved morphology and increased phenotypic expression of key marker proteins calretinin and E-cadherin in PCL/gelatin compared to pure PCL NMSs. In vivo studies in rats revealed that only cell-seeded PCL/gelatin NMS constructs fostered mesothelial healing. Implantation of these constructs leads to the regeneration of new mesothelium tissue. The neo-mesothelium is similar to native mesothelium from hematoxylin and eosin (H&E) and immunohistochemical staining. Taken together, the PCL/gelatin NMSs can be a promising scaffold for mesothelial cell attachment, proliferation, and differentiation, and the cell/scaffold construct can be used in therapeutic applications to reconstruct a mesothelium layer.

Liquefied capsules containing nanogrooved microdiscs and umbilical cord-derived cells for bone tissue engineering.

Surface topography has been shown to influence cell behavior and direct stromal cell differentiation into distinct lineages. Whereas this phenomenon has been verified in two-dimensional cultures, there is an urgent need for a thorough investigation of topography's role within a three-dimensional (3D) environment, as it better replicates the natural cellular environment. A co-culture of Wharton's jelly-derived mesenchymal stem/stromal cells (WJ-MSCs) and human umbilical vein endothelial cells (HUVECs) was encapsulated in a 3D system consisting of a permselective liquefied environment containing freely dispersed spherical microparticles (spheres) or nanogrooved microdiscs (microdiscs). Microdiscs presenting 358 ± 23 nm grooves and 944 ± 49 nm ridges were produced via nanoimprinting of spherical polycaprolactone microparticles between water-soluble polyvinyl alcohol counter molds of nanogrooved templates. Spheres and microdiscs were cultured in vitro with umbilical cord-derived cells in a basal or osteogenic medium within liquefied capsules for 21 days. WJ-MSCs and HUVECs were successfully encapsulated within liquefied capsules containing spheres and microdiscs, ensuring high cellular viability. Results show an enhanced osteogenic differentiation in microdiscs compared to spheres, even in basal medium, evidenced by alkaline phosphatase activity and osteopontin expression. This work suggests that the topographical features present in microdiscs induce the osteogenic differentiation of adhered WJ-MSCs along the contact guidance, without additional differentiation factors. The developed 3D bioencapsulation system comprising topographical features might be suitable for bone tissue engineering approaches with minimum in vitro manipulation.