Extracellular Matrix Hydrogel Research Articles

Reconstructing the Stem Leydig Cell Niche via the Testicular Extracellular Matrix for the Treatment of Testicular Leydig Cell Dysfunction

AbstractTherapies involving the use of stem Leydig cells (SLCs), as testicular mesenchymal stromal cells, have shown great promise in the treatment of Leydig cell (LC) dysfunction in aging males. However, the outcomes of these therapies are not satisfactory. In this study, it is demonstrated that the aging microenvironment of the testicular interstitium impairs the function of SLCs, leading to poor regeneration of LCs and, consequently, inefficient functional restoration. The study develops a decellularized testicular extracellular matrix (dTECM) hydrogel from young pigs and evaluates its safety and feasibility as a supportive niche for the expansion and differentiation of SLCs. dTECM hydrogel facilitates the steroidogenic differentiation of SLCs into LCs, the primary producers of testosterone. The combination of SLCs with a dTECM hydrogel leads to a significant and sustained increase in testosterone levels, which promotes the restoration of spermatogenesis and fertility in an LC‐deficient and aged mouse model. Mechanistically, collagen 1 within the dTECM is identified as a key factor contributing to these effects. Notably, symptoms associated with testosterone deficiency syndrome are significantly alleviated in aged mice. These findings may aid the design of therapeutic interventions for patients with testosterone deficiency in the clinic.

Oviductal extracellular matrix hydrogels enhance in vitro culture of rabbit embryos and reduce deficiencies during assisted reproductive technologies.

In vitro embryo culture often falls short of mimicking the physiological dynamism occurring in the reproductive tract, prompting developmental plasticity in mammalian embryos with consequential genotypic and phenotypic deviations. Recent research highlights the potential of biological derivatives in in vitro culture to mitigate these effects, being the extracellular matrix (ECM) one of the most important components in retaining structural and biological signals derived from the native source tissue. Current bioengineering techniques could provide ECM-based biomaterials mimicking the native environment and offering optimal embryonic development. Rabbit oviducts (n = 24) were decellularized and solubilized to create tissue-specific ECM (OviECM) hydrogels. Following physicochemical characterization, these hydrogels were applied as coatings for the in vitro culture of two-cell embryos over 48h, along with embryos cultured under In vitro control conditions (n = 218/group), which were subsequently transferred to recipient females. A subset of embryos was recovered on day 6 for transcriptomic analysis (n = 75-80/group), while the remaining embryos were used to assess implantation and birth rates. Rabbit weights were monitored over 20 weeks post-delivery, with blood tests conducted at weeks 8 and 20. Bayesian inference methods were used for statistical analysis. Differences were considered relevant if P ≥ 0.8 (80%). No differences in embryo development and morphology were detected between the OviECM coating and In vitro control conditions. However, embryos cultured on these coatings exhibited upregulation of pathways involved in antigen presentation and immune system activation, as well as, increased cellular response to external stimulus and intracellular protein transport. The implantation and live birth rates were significantly higher in the coating group than in the In vitro control group (30.8% vs. 26.1% and 21.2% vs. 18.1%, respectively). During the first 20 weeks of life, the animals from the coating group showed higher weights than the In vitro control group P0 > 0.8. The animals of both experimental groups showed normal blood parameters. Implementation of OviECM coatings allows for improving in vitro conditions and decreases postnatal phenotypic deviations after assisted reproductive technology (ART). This study could initiate a new embryo culture techniques era to guarantee that ART is utilized in the most efficient and safest possible practice.

Decellularized porcine dermal hydrogel enhances implant-based wound healing in the setting of irradiation

Acellular Dermal Matrix (ADM) provides mechanical and soft tissue support in implant-based breast reconstruction, and has shown to modulate the healing response. However, skin flap necrosis, edema, and previous radiation therapy can hinder ADM integration. Effective biomaterial integration requires regulating the immune response, fibrosis, and adipocyte-driven functionalization. Extracellular matrix (ECM) hydrogels have demonstrated utility in tissue regeneration, and decreasing inflammation and fibrosis in various tissues. Therefore, we hypothesized that a Decellularized Porcine Dermal (DPD) hydrogel to support ADM integration would prevent excessive fibrosis, regulate the macrophage response, and promote adipogenesis. Exploration of DPD hydrogel during ADM implantation in mice (healthy and radiated) revealed long-term effects of irradiation on implant wound healing. DPD hydrogel rescued radiation-induced fibrosis, restoring capsule thickness of healthy mice, and did not increase the fibroblast migration into the ADM. As a modulating soft tissue filler, DPD hydrogel also promoted adipocyte infiltration in healthy and irradiated mice. Detailed macrophage analysis showed that radiation led to the increase in pro-inflammatory, transition, and reparative markers. Despite relatively subtle effects on individual macrophage phenotype markers, multidimensional flow cytometry analysis revealed that DPD hydrogel temporally regulated two subpopulations. he presence of DPD resulted in significantly reduced CD9HiArg1HiCD301bLo and CD163HiCD38HiCD301bHi macrophages in healthy mice at one week, and a significant increase in CD9High macrophages with low expression of other markers at 6 weeks in irradiated mice. DPD hydrogel promotes a decreased fibrotic, and adipocyte-promoting coordination of wound healing in healthy and irradiated wound beds while not disrupting the immunomodulatory effects of ADM. STATEMENT OF SIGNIFICANCE: Acellular Dermal Matrix (ADM) provides mechanical and soft tissue support in post-mastectomy implant-based breast reconstruction, and positively affects wound healing. Following breast reconstruction, skin flap necrosis, edema, and previous radiation therapy can hinder ADM integration. Effective wound healing and biomaterial integration requires regulating the cellular immune response. Extracellular matrix hydrogels have demonstrated utility in tissue regeneration and decreasing inflammation and fibrosis in various tissues, but has yet to be utilized in the setting of breast reconstruction. Here, we demonstrated that a decellularized dermal hydrogel as an adjunct to ADM, decreases fibrosis and promotes adipogenesis during the coordination of wound healing in healthy and clinically relevant microenvironments that have received radiation therapy while not disrupting the immunomodulatory effects of implanted ADM.

Preparation and characterization of bovine dental pulp-derived extracellular matrix hydrogel for regenerative endodontic applications: an in vitro study

BackgroundThe use of biological scaffolds in regenerative endodontics has gained much attention in recent years. The search for a new biomimetic scaffold that contains tissue-specific cell homing factors could lead to more predictable tissue regeneration. The aim of this study was to prepare and characterize decellularized bovine dental pulp-derived extracellular matrix (P-ECM) hydrogels for regenerative endodontic applications.MethodsFreshly extracted bovine molar teeth were collected. Bovine dental pulp tissues were harvested, and stored at -40º C. For decellularization, a 5-day protocol was implemented incorporating trypsin/EDTA, deionized water and DNase treatment. Decellularization was evaluated by DNA quantification and histological examination to assess collagen and glycosaminoglycans (GAGs) content. This was followed by the preparation of P-ECM hydrogel alone or combined with hyaluronic acid gel (P-ECM + HA). The fabricated scaffolds were then characterized using protein quantification, hydrogel topology and porosity, biodegradability, and growth factor content using Enzyme-linked immunosorbent assay (ELISA): transforming growth factor beta-1(TGF-β1), basic fibroblast growth factor (bFGF), bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF).ResultsDecellularization was histologically confirmed, and DNA content was below (50 ng/mg tissue). P-ECM hydrogel was prepared with a final ECM concentration of 3.00 mg/ml while P-ECM + HA hydrogel was prepared with a final ECM concentration of 1.5 mg/ml. Total protein content in P-ECM hydrogel was found to be (439.0 ± 123.4 µg/µl). P-ECM + HA showed sustained protein release while the P-ECM group showed gradual decreasing release. Degradation was higher in P-ECM + HA which had a significantly larger fiber diameter, while P-ECM had a larger pore area percentage. ELISA confirmed the retention and release of growth factors where P-ECM hydrogel had higher BMP-2 release, while P-ECM + HA had higher release of TGF-β1, bFGF, and VEGF.ConclusionsBoth P-ECM and P-ECM + HA retained their bioactive properties demonstrating a potential role as functionalized scaffolds for regenerative endodontic procedures.

Bovine pulp extracellular matrix hydrogel for regenerative endodontic applications: in vitro characterization and in vivo analysis in a necrotic tooth model

BackgroundRegenerative endodontic procedures (REPs) offer the promise of restoring vitality and function to a previously necrotic and infected tooth. However, the nature of regenerated tissues following REPs remains unpredictable and uncontrollable. Decellularized extracellular matrix scaffolds have gained recent attention as scaffolds for regenerative endodontics.ObjectivesPreparation and characterization of a bovine dental pulp-derived extracellular matrix (P-ECM) hydrogel for regenerative endodontic applications. Biocompatibility and regenerative capacity of the prepared scaffold were evaluated in vivo in a canine animal model.MethodsFifteen freshly extracted bovine molar teeth were used to prepare P-ECM hydrogels following approval of the institutional review board of the faculty of dentistry, Alexandria University. Decellularization and lyophilization of the extracted pulp tissues, DNA quantification and histological examination of decellularized P-ECM were done. P-ECM hydrogel was prepared by digestion of decellularized pulps. Prepared scaffolds were evaluated for protein content and release as well as release of VEGF, bFGF, TGF-β1 and BMP2 using ELISA. Rabbit dental pulp stem cells’ (rDPSCs) viability in response to P-ECM hydrogels was performed. Finally, proof-of-concept of the regenerative capacity of P-ECM scaffolds was assessed in an infected mature canine tooth model following REPs versus blood clot (BC), injectable platelet-rich fibrin (i-PRF) or hyaluronic acid (HA). Statistical analysis was done using independent t test, the Friedman test and chi-square tests (p value ≤ 0.05).ResultsDNA was found to be below the cut-off point (50 ng/mg tissue). Histological evaluation revealed absence of nuclei, retention of glycosaminoglycans (GAGs) and collagen content, respectively. P-ECM hydrogel had a total protein content of (493.12 µg/µl) and protein release was detected up to 14 days. P-ECM hydrogel also retained VEGF, bFGF, TGF-β1 and BMP2. P-ECM hydrogel maintained the viability of rDPSCs as compared to cells cultured under control conditions. P-ECM hydrogel triggered more organized tissues compared to BC, i-PRF and HA when used in REPs for necrotic mature teeth in dogs. Periapical inflammation was significantly less in HA and P-ECM groups compared to blood-derived scaffolds.ConclusionBovine dental pulp-derived extracellular matrix (P-ECM) hydrogel scaffold retained its bioactive properties and demonstrated a promising potential in regenerative endodontic procedures compared to conventional blood-derived scaffolds.

Durable Muscle Extracellular Matrix Engineered with Adhesive Phenolic Moieties for Effective Skeletal Muscle Regeneration in Muscle Atrophy.

Muscle atrophy detrimentally impacts health and exacerbates physical disability, leading to increased mortality. In particular, sarcopenia, aging-related degenerative muscle loss, necessitates urgent remedies. Current approaches for treating muscle atrophy include exercise and nutrition, while drug exploration remains in its early stages. Cell therapy, focusing on satellite cells, faces significant challenge due to poor engraftment, safety issue, and high cost. Cell-free approach using extracellular matrix (ECM) shows a regenerative potential, but a lack of mechanical and adhesive properties hinders prolonged efficacy of ECM therapy. Here, durable muscle ECM (MEM) hydrogels for muscle atrophy by fortifying MEM with adhesive phenolic moieties including catechol and pyrogallol are demonstrated. The resultant phenolic MEM hydrogels exhibit enhanced mechanical and adhesive properties and provide sustained muscle-like microenvironments to address muscle atrophy. No local and systemic toxicities are observed after phenolic MEM injection into tibialis anterior muscle. Notably, these engineered MEM hydrogels, devoid of cells or drugs, induce tissue rejuvenation by promoting muscle protein synthesis and facilitating functional muscle recovery in mouse models of disuse- and age-induced atrophy. This study introduces cell-free, ECM-based therapeutics with translational potential for muscle atrophy by reversing muscle loss and restoring function.

Designing injectable dermal matrix hydrogel combined with silver nanoparticles for methicillin-resistant Staphylococcus aureus infected wounds healing

Hydrogel-based delivery systems have now emerged as a pivotal platform for addressing chronic tissue defects, leveraging their innate capacity to suppress pathogenic infections and facilitate expedited tissue regeneration. In this work, an injectable hydrogel dressing, termed AgNPs-dermal matrix hydrogel (Ag@ADMH), has been designed to expedite the healing process of wounds afflicted with methicillin-resistant Staphylococcus aureus (MRSA), featuring sustained antibacterial efficacy. The synthesis of the hydrogel dressing entailed a self-assembly process of collagen fibers within an acellular dermal matrix to construct a three-dimensional scaffold, encapsulated with plant polyphenol-functionalized silver nanoparticles (AgNPs). The Ag@ADMH demonstrated exceptional biocompatibility, and enables a sustained release of AgNPs, ensuring prolonged antimicrobial activity. Moreover, the in vitro RT-qPCR analysis revealed that compared with ADMH, Ag@ADMH diminish the expression of iNOS while augmenting CD206 expression, thereby mitigating the inflammatory response and fostering wound healing. Especially, the Ag@ADMH facilitated a reduction in M1 macrophage polarization, as evidenced by a significant decrement in the M1 polarization trend and an enhanced M2/M1 ratio in dermal matrix hydrogels laden with AgNPs, corroborated by confocal microscopy and flow cytometry analyses of macrophage phenotypes. The in vivo assessments indicated that Ag@ADMH minimized fibrous capsule formation. In a full-thickness skin defect model of MRSA infection, the formulation significantly attenuated the inflammatory response by reducing MPO and CD68 expression levels, concurrently promoting collagen synthesis and CD34 expression, pivotal for vasculogenesis, thereby accelerating the resolution of MRSA-infected wounds. These attributes underscore the injectable extracellular matrix hydrogel as a formidable strategy for the remediation and regeneration of infected wounds.Graphical

A patch comprising human umbilical cord-derived hydrogel and mesenchymal stem cells promotes pressure ulcer wound healing

Pressure ulcers (PUs) are common skin injuries known for their high morbidity, rapid onset, susceptibility to infection, and challenging healing process. One potential therapy for PUs is cell-based therapy using mesenchymal stem cells (MSCs). However, poor survival and low cell retention of MSCs on skin lesions limit their therapeutic effects and applications. In this study, we prepared an extracellular matrix (dECM) hydrogel decellularized from the human umbilical cord (UC). A patch composed of UC-dECM and UC-MSCs was employed in the treatment of PUs in C57BL/6 mice. Our results indicate that the UC-dECM hydrogel effectively sustains cell viability, enhances the stemness-related gene expression in UC-MSCs, and promotes human umbilical vein endothelial cells (HUVECs) migration and angiogenesis. Compared to the groups treated with the patch containing only UC-dECM, injection of UC-MSCs or gauze dressing, the patch combining UC-dECM hydrogel with UC-MSCs significantly accelerated PU healing. This positive outcome can be attributed to the promotion of tissue re-epithelialization, collagen deposition, angiogenesis, and inflammation inhibition. Our results suggest that the composite patch, comprised of UC-dECM hydrogel and UC-MSCs, may be a promising therapeutic approach for PU treatment.

Novel 3D bioprinting approach for spinal cord injury repair using neural stem cells and TGF-β1 monoclonal antibody

ObjectiveTo investigate the repair of spinal cord injury (SCI) in rats using 3D bioprinted decellularized extracellular matrix (dECM) hydrogel, neural stem cells (NSCs), and TGF-β1 monoclonal antibody. MethodsThe spinal cord-derived dECM hydrogel (SC-dECM-gel) was optimized for 3D printing. Rheological tests established a 3 ​% concentration as optimal. In vitro tests assessed the effects of TGF-β1 monoclonal antibody on NSC viability and differentiation. A rat SCI model was treated with the printed gel, and recovery was monitored using the Basso-Beattie-Bresnahan test and evoked potentials. ResultsThe 3 ​% SC-dECM-gel showed superior rheological properties. TGF-β1 monoclonal antibody enhanced NSC survival and differentiation in vitro. In vivo, the 3D bioprinted gel significantly improved motor function and promoted neuronal regeneration. Conclusion3D bioprinted SC-dECM-gel loaded with NSCs and TGF-β1 monoclonal antibody effectively restores motor function and promotes regeneration in SCI rats, offering a promising approach for SCI treatment.

A 3D Epithelial-Mesenchymal Co-Culture Model of the Airway Wall Using Native Lung Extracellular Matrix.

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterized by ongoing inflammation, impaired tissue repair, and aberrant interplay between airway epithelium and fibroblasts, resulting in an altered extracellular matrix (ECM) composition. The ECM is the three-dimensional (3D) scaffold that provides mechanical support and biochemical signals to cells, now recognized not only as a consequence but as a potential driver of disease progression. To elucidate how the ECM influences pathophysiological changes occurring in COPD, in vitro models are needed that incorporate the ECM. ECM hydrogels are a novel experimental tool for incorporating the ECM in experimental setups. We developed an airway wall model by combining lung-derived ECM hydrogels with a co-culture of primary human fibroblasts and epithelial cells at an air-liquid interface. Collagen IV and a mixture of collagen I, fibronectin, and bovine serum albumin were used as basement membrane-mimicking coatings. The model was initially assembled using porcine lung-derived ECM hydrogels and subsequently with COPD and non-COPD human lung-derived ECM hydrogels. The resulting 3D construct exhibited considerable contraction and supported co-culture, resulting in a differentiated epithelial layer. This multi-component 3D model allows the investigation of remodelling mechanisms, exploring ECM involvement in cellular crosstalk, and holds promise as a model for drug discovery studies exploring ECM involvement in cellular interactions.

An injectable decellularized extracellular matrix hydrogel with cortical neuron-derived exosomes enhances tissue repair following traumatic spinal cord injury

Traumatic spinal cord injury (SCI), known for its limited intrinsic regeneration capacity, often results in considerable neurological impairment. Studies suggest that therapeutic techniques utilizing exosomes (Exo) to promote tissue regeneration and modulate immune responses are promising for SCI treatment. However, combining exosome therapy with biomaterials for SCI treatment is not very effective. This study developed an adhesive hydrogel using exosomes secreted by cortical neurons derived from human induced pluripotent stem cells (iPSCs) and decellularized extracellular matrix (dECM) from human umbilical cord mesenchymal stem cells (hUCMSCs) to enhance motor function recovery post-SCI. In vitro assessments demonstrated the excellent cytocompatibility of the dECM hydrogel. Additionally, the Exo-dECM hydrogel facilitated the polarization of early M2 macrophages, reduced neuronal apoptosis, and established a pro-regenerative microenvironment in a rodent SCI model. Subsequent analyses revealed significant activation of endogenous neural stem cells and promotion of axon regeneration and remyelination at eight weeks post-surgery. The Exo-dECM hydrogel also promoted the functional recovery and preservation of urinary tissue in SCI-afflicted rats. These findings highlighted that the Exo-dECM hydrogel is a promising therapeutic strategy for treating SCI.

Tumor Microenvironment Based on Extracellular Matrix Hydrogels for On-Chip Drug Screening.

Recent advances in three-dimensional (3D) culturing and nanotechnology offer promising pathways to overcome the limitations of drug screening, particularly for tumors like neuroblastoma. In this study, we develop a high-throughput microfluidic chip that integrates a concentration gradient generator (CGG) with a 3D co-culture system, constructing the vascularized microenvironment in tumors by co-culturing neuroblastoma (SY5Y cell line) and human brain microvascular endothelial cells (HBMVECs) within a decellularized extracellular matrix (dECM) hydrogels. The automated platform enhances the simulation of the tumor microenvironment and allows for the precise control of the concentrations of nanomedicines, which is crucial for evaluating therapeutic efficacy. The findings demonstrate that the high-throughput platform can significantly accelerate drug discovery. It efficiently screens and analyzes drug interactions in a biologically relevant setting, potentially revolutionizing the drug screening process.

Generation of a pancreas derived hydrogel for the culture of hiPSC derived pancreatic endocrine cells

Stem cell-derived β-cells (SC-BCs) represent a potential source for curing diabetes. To date, in vitro generated SC-BCs display an immature phenotype and lack important features in comparison to their bona-fide counterparts. Transplantation into a living animal promotes SC-BCs maturation, indicating that components of the in vivo microenvironment trigger final SC-BCs development. Here, we investigated whether cues of the pancreas specific extracellular matrix (ECM) can improve the differentiation of human induced pluripotent stem cells (hiPSCs) towards β-cells in vitro. To this aim, a pancreas specific ECM (PanMa) hydrogel was generated from decellularized porcine pancreas and its effect on the differentiation of hiPSC-derived pancreatic hormone expressing cells (HECs) was tested. The hydrogel solidified upon neutralization at 37 °C with gelation kinetics similar to Matrigel. Cytocompatibility of the PanMa hydrogel was demonstrated for a culture duration of 21 days. Encapsulation and culture of HECs in the PanMa hydrogel over 7 days resulted in a stable gene and protein expression of most β-cell markers, but did not improve β-cell identity. In conclusion, the study describes the production of a PanMa hydrogel, which provides the basis for the development of ECM hydrogels that are more adapted to the demands of SC-BCs.

Injectable decellularized extracellular matrix hydrogel with cell-adaptable supramolecular network enhances cartilage regeneration by regulating inflammation and facilitating chondrogenesis

Osteoarthritis, characterized by progressive loss of cartilage, affects millions of people worldwide and clinically lacks effective treatments. Herein, we present an injectable, biodegradable supramolecular decellularized extracellular matrix (dECM) hydrogel, which can be injected into the joints and provide biomimetic microenvironments to drive cartilage regeneration. Benefiting from the cell-adaptable dynamic network and cartilage-specific compositions, the supramolecular dECM hydrogel not only enhances cell proliferation and migration, but also facilitates chondrogenesis. Furthermore, compared with the conventional dECM hydrogels, the supramolecular dECM hydrogel is instrumental in regulating inflammation, which consequently leads to a marked suppression of genes linked to cell death and cartilage degradation. In vivo analysis confirms that stem cells, when delivered via the supramolecular dECM hydrogel, remain viable for up to three months within the restored cartilage. The regenerated tissue exhibits hyaline-cartilage structure, good mechanical properties, and cartilage-specific extracellular matrix deposition that align closely with those of native cartilage. We envision that this supramolecular dECM hydrogel could serve as a valuable platform for cartilage regeneration and could strongly facilitate the clinical translation of dECM-based materials for tissue regeneration.

Incorporation of calcium phosphate cement into decellularized extracellular matrix enhances its bone regenerative properties

Decellularized extracellular matrix (dECM) hydrogels are engineered constructs that are widely-used in the field of regenerative medicine. However, the development of ECM-based hydrogels for bone tissue engineering requires enhancement in its osteogenic properties. For this purpose, we initially employed bone-derived dECM hydrogel (dECM-Hy) in combination with calcium phosphate cement (CPC) paste to improve the biological and structural properties of the dECM hydrogel. A decellularization protocol for bovine bone was developed to prepare dECM-Hy, and the mechanically-tuned dECM/CPC-Hy was built based on both rheological and mechanical characteristics. The dECM/CPC-Hy displayed a double swelling ratio and compressive strength. An interconnected structure with distinct hydroxyapatite crystals was evident in dECM/CPC-Hy. The expression levels of Alp, Runx2 and Ocn genes were upregulated in dECM/CPC-Hy compared to the dECM-Hy. A 14-day follow-up of the rats receiving subcutaneous implanted dECM-Hy, dECM/CPC-Hy and mesenchymal stem cells (MSCs)-embedded (dECM/CPC/MSCs-Hy) showed no toxicity, inflammatory factor expression or pathological changes. Radiography and computed tomography (CT) of the calvarial defects revealed new bone formation and elevated number of osteoblasts-osteocytes and osteons in dECM/CPC-Hy and dECM/CPC/MSCs-Hy compared to the control groups. These findings indicate that the dECM/CPC-Hy has substantial potential for bone tissue engineering.

Transformative potential of three-dimensional bioprinting technology for advanced organoid research

Organoid research has emerged as a transformative field in biomedicine, focusing on the in vitro development of 3-dimensional (3D) structures that mimic human organs. Derived from various types of stem cells, organoids closely replicate human organ structures and functions, offering significant advantages over 2-dimensional cell cultures and animal models, particularly for drug development, tissue engineering, and precision medicine. Recent innovations, including the integration of biofabrication technologies, have significantly increased the structural complexity and maturity of organoids, expanding their biomedical applications. A critical factor in organoid culture is the utilization of the extracellular matrix (ECM), particularly decellularized ECM hydrogels. These hydrogels are instrumental in organoid growth and development, effectively simulating in vivo environments and supporting organoid functionality across various organ systems. The integration of 3D bioprinting technology into organoid research marks a transformative shift that has enabled the creation of intricate and customized structures. This review demonstrates that these technological innovations have not only revolutionized tissue engineering and regenerative medicine, but also hold immense potential for pharmacology, disease modeling, and personalized medical interventions. The synergistic integration of these technologies presents a promising future for medical research, paving the way for significant advancements in disease modeling, drug discovery, and the development of patient-specific treatments, and marking our entry into a new era of precision medicine and personalized healthcare solutions.

Accelerated cartilage regeneration through immunomodulation and enhanced chondrogenesis by an extracellular matrix hydrogel encapsulating Kartogenin

Articular cartilage is crucial for the functional integrity of joints yet vulnerable to a spectrum of injuries. The adverse immune microenvironment ensuing from injury, coupled with the intrinsic property of the tissue characterized by limited cellularity, poses a significant challenge to the reconstruction of cartilage defect. In this study, an extracellular matrix hydrogel derived from porcine small intestinal submucosa (SIS) with encapsulation of Kartogenin (KGN) has been designed for the cartilage repair and regeneration. The SIS hydrogel, which possessed a three-dimensional porous structure akin to the natural cartilage, has provided a scaffold essential for the progenitor cells engaged in the repair process and sustained release of KGN. As shown by in vitro experiments, the KGN could recruit host endogenous bone marrow-derived mesenchymal stem cells (BMSCs) and induce them to differentiate into chondrocytes, thus enabling in situ cartilage regeneration without cell transplantation. Notably, the bioactive component of SIS was further revealed to possess excellent immunomodulatory capacity to induce the phenotypic shift from M1 to M2 macrophages, which could enhance the chondrogenic differentiation of BMSCs indirectly. Additionally, in vivo experiments showed that the regenerated tissues of the composite SIS hydrogel group were close to the natural hyaline cartilage. Leveraging the combined effects of KGN and SIS hydrogel, this innovative composite material shows great potential as a biomaterial for effective cartilage repair and regeneration.

Tissue-scale in vitro epithelial wrinkling and wrinkle-to-fold transition

Although epithelial folding is commonly studied using in vivo animal models, such models exhibit critical limitations in terms of real-time observation and independent control of experimental parameters. Here, we develop a tissue-scale in vitro epithelial bilayer folding model that incorporates an epithelium and extracellular matrix (ECM) hydrogel, thereby emulating various folding structures found in in vivo epithelial tissue. Beyond mere folding, our in vitro model realizes a hierarchical transition in the epithelial bilayer, shifting from periodic wrinkles to a single deep fold under compression. Experimental and theoretical investigations of the in vitro model imply that both the strain-stiffening of epithelium and the poroelasticity of ECM influence the folded structures of epithelial tissue. The proposed in vitro model will aid in investigating the underlying mechanism of tissue-scale in vivo epithelial folding relevant to developmental biology and tissue engineering.

3D Bioprinted Tissue-Engineered Bone with Enhanced Mechanical Strength and Bioactivities: Accelerating Bone Defect Repair through Sequential Immunomodulatory Properties.

In this study, a new-generation tissue-engineered bone capable of temporally regulating the immune response, balancing proinflammatory and anti-inflammatory activities, and facilitating bone regeneration and repair to address the challenges of delayed healing and nonunion in large-sized bone defects, is innovatively developed. Using the innovative techniques including multiphysics-assisted combined decellularization, side-chain biochemical modification, and sterile freeze-drying, a novel photocurable extracellular matrix hydrogel, methacrylated bone-derived decellularized extracellular matrix (bdECM-MA), is synthesized. After incorporating the bdECM-MA with silicon-substituted calcium phosphate and bone marrow mesenchymal stem cells, the tissue-engineered bone is fabricated through digital light processing 3D bioprinting. This study provides in vitro confirmation that the engineered bone maintains high cellular viability while achieving MPa-level mechanical strength. Moreover, this engineered bone exhibits excellent osteogenesis, angiogenesis, and immunomodulatory functions. One of the molecular mechanisms of the immunomodulatory function involves the inhibition of the p38-MAPK pathway. A pioneering in vivo discovery is that the natural biomaterial-based tissue-engineered bone demonstrates sequential immunomodulatory properties that activate proinflammatory and anti-inflammatory responses in succession, significantly accelerating the repair of bone defects. This study provides a new research basis and an effective method for developing autogenous bone substitute materials and treating large-sized bone defects.

Characterization of a decellularized pericardium extracellular matrix hydrogel for regenerative medicine: insights on animal-to-animal variability.

In the past years, the use of hydrogels derived from decellularized extracellular matrix (dECM) for regenerative medicine purposes has significantly increased. The intrinsic bioactive and immunomodulatory properties indicate these materials as promising candidates for therapeutical applications. However, to date, limitations such as animal-to-animal variability still hinder the clinical translation. Moreover, the choice of tissue source, decellularization and solubilization protocols leads to differences in dECM-derived hydrogels. In this context, detailed characterization of chemical, physical and biological properties of the hydrogels should be performed, with attention to how these properties can be affected by animal-to-animal variability. Herein, we report a detailed characterization of a hydrogel derived from the decellularized extracellular matrix of bovine pericardium (dBP). Protein content, rheological properties, injectability, surface microstructure, in vitro stability and cytocompatibility were evaluated, with particular attention to animal-to-animal variability. The gelation process showed to be thermoresponsive and the obtained dBP hydrogels are injectable, porous, stable up to 2weeks in aqueous media, rapidly degrading in enzymatic environment and cytocompatible, able to maintain cell viability in human mesenchymal stromal cells. Results from proteomic analysis proved that dBP hydrogels are highly rich in composition, preserving bioactive proteoglycans and glycoproteins in addition to structural proteins such as collagen. With respect to the chemical composition, animal-to-animal variability was shown, but the biological properties were not affected, which remained consistent in different batches. Taken together these results show that dBP hydrogels are excellent candidates for regenerative medicine applications.