Tissue engineering and regenerative medicine最新文献

Background: Chronic kidney disease (CKD) is a progressive disorder that leads to significant structural and functional changes in the kidneys, posing a major global health concern and contributing to high mortality rates.

Methods: The urgent need for innovative treatments is evident. Mesenchymal stem cells (MSCs) are well-regarded in regenerative medicine for their ability to repair tissue and modulate immune responses. Emerging research indicates that the therapeutic benefits of MSCs are largely mediated by the secretion of extracellular vesicles (EVs), particularly exosomes (MSC-Exos), which replicate the effects of MSCs by delivering genetic materials and proteins to target cells.

Results: MSC-Exos are novel natural carriers for targeted gene or drug delivery, offering biocompatibility, intrinsic targeting capabilities, and bioactive cargo to modulate recipient cells. They represent a groundbreaking platform for precision medicine, enhancing therapeutic efficacy with minimal immunogenicity and off-target effects. Moreover, embedding exosomes within hydrogels has emerged as a promising strategy to maintain their biological activity and enable a controlled release.

Conclusion: This review explores the roles of MSC-Exos in CKD pathophysiology, highlights the renoprotective effects of MSC-Exos for various sources, and provides a comprehensive overview of how hydrogel biomaterials present a promising approach for integrating exosomes to enhance therapeutic outcomes. The use of hydrogels to encapsulate exosomes improves their sustained release and stability in diseased kidney tissues, providing an innovative strategy to enhance precision therapies.

Background: Acellular tubular artery scaffolds offer structural support for vascular regeneration but are inherently limited by poor anticoagulant properties, which increases the risk of thrombus formation following implantation. This thrombogenicity remains a major obstacle to their clinical application, particularly in small-diameter vascular grafts.

Methods: To address this challenge, the present study investigates the use of the Layer-by-Layer (LbL) assembly technique for heparin immobilization under low-speed rotation. Utilizing a roller tube system, heparin was immobilized onto decellularized scaffolds through electrostatic interactions facilitated by a DHI-based linker. This low-speed rotation LbL approach enhanced the uniformity and stability of heparin deposition compared to traditional static methods. One, 4, 7, 10, 13 deposition cycles were performed to achieve optimal heparin loading, resulting in scaffolds capable of sustained heparin release over 28 days.

Results: The heparinized scaffolds exhibited an initial burst release (approximately 80%), followed by a sustained phase with 18.24% ± 0.242 remaining to support prolonged anticoagulant activity. Importantly, the modified scaffolds significantly reduced thrombus formation and exhibited minimal hemolytic activity, indicating improved hemocompatibility. In addition to their antithrombotic properties, the scaffolds also promoted endothelial cell adhesion, which is critical for restoring vascular integrity, regulating vascular tone, and maintaining long-term patency.

Conclusion: These findings highlight the efficacy of roller-assisted LbL heparinization as a practical and scalable strategy to enhance the blood compatibility of acellular vascular grafts. This method holds considerable promise for addressing thrombogenicity in vascular tissue engineering and advancing the clinical translation of bioengineered vascular constructs.

Background: Burn injuries are characterized by extensive and prolonged inflammatory responses that impair wound healing, especially in deep burns. Understanding the post-burn fibroblast dynamics in wound healing is critical to improve recovery and minimize scarring. This study aimed to develop a 3D reconstructed human skin (RhS) burn model to mimic superficial, partial-thickness, and deep burn injuries and assess fibroblast behavior over one week.

Methods: RhS consisted of a reconstructed epidermis on a fibroblast populated collagen hydrogel dermis. Papillary (fibroblast activation protein; FAP +) and reticular (FAP-) fibroblasts located themselves in the upper and lower regions respectively within the dermal compartment in line with native skin. Burns of increasing temperatures (70 °C, 110 °C, and 140 °C) were introduced and RhS was analyzed up to one-week post-burn.

Results: Lactate dehydrogenase (LDH) staining for metabolic active cells in tissue sections enabled distinct histological zones to be observed in RhS with partial (110 °C) and deep burns (140 °C): including a viable fibroblast zone (zone V), a mixed dead and viable fibroblast zone (zone M), and a necrotic zone (zone N). Fibroblast migration from the wound edge (M) into the viable area (V) and changes in fibroblast phenotype, particularly an increase in papillary fibroblast markers (FAP +), were observed, with a marked increased expression of Ki67 in fibroblasts at the burn wound edge (M). Additionally, burn temperature influenced the protein secretion of inflammatory and tissue remodeling mediators SAA, NGAL, MRP8/13, ICAM-1, CCL20, and MMP-9.

Conclusion: The RhS burn model enables complex fibroblast dynamics post-burn to be investigated in an organotypic model, providing a platform for studying burn pathophysiology which can be used for evaluating potential therapeutic strategies for enhancing burn wound healing and minimizing scarring in the future.

Background: Alveolar bone loss following trauma, periodontal disease, congenital anomalies, or tooth extraction poses a major challenge for oral rehabilitation, especially in implant dentistry. Traditional grafting techniques using autografts, allografts, or xenografts provide limited predictability due to issues of resorption, donor morbidity, and immune incompatibility. Advances in three-dimensional (3D) printing now enable preparation of patient-specific biodegradable scaffolds designed using 3D imaging, like cone beam computed tomography (CBCT) and computer-aided design (CAD), allowing precise replication of defect geometry and tailored biological performance.

Methods: This review article summarizes the most recent preclinical and clinical studies investigating biodegradable 3D printed scaffolds for alveolar bone regeneration. Studies were searched in the PubMed database, Scopus, and Google Scholar with the most relevant keywords related to 3D printed scaffolds focusing on alveolar bone regeneration.

Results: Polymers such as PLA, PCL, and PLGA offer mechanical stability and printability but require bioactive modification. Ceramics, including hydroxyapatite and tricalcium phosphate, provide osteoconductivity yet are brittle. Hydrogels such as gelatin and alginate support cellular viability but lack structural strength. Composite scaffolds integrating polymers with ceramics or bioactive agents demonstrated superior osteogenic potential. Clinical applications included alveolar ridge preservation, guided bone regeneration, cleft repair, and implant site reconstruction. Emerging strategies utilizing bioinks with stem cells and growth factors further enhanced the biological properties of patient-specific 3D printed scaffolds for clinical purposes.

Conclusion: 3D printed patient-specific biodegradable scaffolds represent a promising alternative to conventional grafting, offering precise defect reconstruction, improved biological integration, and translational potential in maxillofacial surgery. Continued optimization of material printing combinations and vascularization strategies will be critical to achieving long-term clinical success.

Background: Mesenchymal stem cells (MSCs) derived from bone marrow (BM), adipose tissue (AD), and umbilical cord (UC) exhibit therapeutic potential in regenerative medicine. However, their properties, including transcriptomic profiles, vary based on tissue origin, passage stage, and isolation method, complicating their clinical standardization. Addressing these unresolved differences requires comprehensive approaches, such as RNA sequencing, to analyze transcriptomic profiles in detail.

Methods: In this study, RNA-seq was employed to analyze MSC transcriptomes from BM, AD, and UC tissues. UC MSCs were isolated using enzymatic digestion or the Minimal Cube Explant (MCE) method (smumf cells), and transcriptomes of early (P3-4) and late (P10) passages of smumf cells were compared. Differentially expressed genes (DEGs) were identified, followed by transcription factor (TF) and pathway analyses.

Results: Fetal MSCs (UC and smumf cells) exhibited distinct transcriptomic profiles compared to adult MSCs (BM and AD), with 2,208 upregulated and 2,594 downregulated DEGs. Key transcription factors, such as E2F1 and NF-κB1, and pathways, including glycolysis, cholesterol biosynthesis, and TNF-α signaling, were enriched in fetal MSCs. smumf cells demonstrated transcriptomic stability between early and late passages, with only 12 DEGs identified. Additionally, smumf cells showed enhanced innate immune responses and cholesterol metabolism compared to enzymatically isolated UC MSCs.

Conclusion: This study provides a comprehensive transcriptomic comparison of MSCs, highlighting the superior transcriptional stability, immunomodulatory capacity, and metabolic flexibility of fetal MSCs, particularly smumf cells. These findings underscore their potential as a reliable cell source for therapeutic applications and encourage further exploration of their clinical application.

Background: Cartilage has limited self-repair capacity, making it vulnerable to damage from aging, trauma, or mechanical stress, which can progress into severe joint disorders. Stem cell-based therapies offer a promising solution for cartilage regeneration and the development of transplantable cartilage constructs.

Methods: This review highlights recent advances in stem cell in vitro chondrogenic differentiation and their therapeutic applications. It explores various stem cell sources and the mechanisms guiding chondrogenesis, including dynamic culture conditions, differentiation via intermediate lineages, biomaterial scaffolds, and genetic or epigenetic modulation.

Results: Results: The roles of small molecules and growth factors in directing stem cells toward functional chondrocytes are also discussed. Additionally, we briefly examine the emerging integration of artificial intelligence (AI) in cartilage tissue engineering. AI applications such as predicting differentiation outcomes, monitoring chondrogenic progression in real-time, and identifying small-molecule enhancers are poised to accelerate discovery and standardization in the field.

Conclusion: The review concludes with an analysis of current limitations and translational challenges that should be addressed to obtain the clinical potential of stem cell-derived chondrocyte therapies.

Background: Implant supporting materials are currently used in breast reconstruction. However, when used in humans, they are associated with several problems. To address these issues, a new mesh called TissueDerm was created by combining a collagen sponge with a 3D printed polycaprolactone (PCL) mesh. It has shown promising results in pig experiments and could potentially replace the most commonly used acellular dermal matrix (ADM) for breast reconstruction.

Methods: Four 12-month-old minipigs were used in this experiment. Silicone implants were wrapped with ADM or TissueDerm, and the breast tissue was excised and implanted along with the wrapped implants. Three months later, the minipigs were sacrificed and the skin and mammary gland tissue surrounding the implants were harvested for further analysis. Histological analyses and immunostaining were performed.

Results: Although there was no significant difference in capsule thickness between the ADM and TissueDerm groups, collagen was more involved in TissueDerm, leading to better tissue regeneration. TissueDerm also induced lower levels of inflammatory markers TNF-α and IL-6 compared to ADM. However, capsules induced with ADM had significantly higher collagen fiber alignment and alpha-smooth muscle actin (α-SMA) positive immunoreactivity, suggesting that TissueDerm may be less likely to cause spherical contractures in the porcine model compared to ADM.

Conclusions: The study found that TissueDerm has advantages over ADM in terms of easier tissue invasion and reduced spheroidization in a porcine model. The results showed that TissueDerm is a promising new mesh for implant-based breast reconstruction (IBBR) and could potentially replace ADM.

Background: Upon injury, tissue repair often leads to a loss in functionality, organisation, and structure. The immune system, particularly macrophages, is crucial during tissue healing. Macrophages polarise into pro-inflammatory M1 and anti-inflammatory M2 subsets, regulating various stages of tissue healing. Macrophages steer fibroblasts in the process of extracellular matrix degradation, synthesis, and rearrangement. However, the direct role of paracrine signalling by different macrophage phenotypes on fibroblast-induced structural tissue remodelling remains elusive. Therefore, this study aimed to explore how paracrine factors from M1, M2a, and M2c macrophages affect fibroblast remodelling abilities in an in vitro model system.

Methods: Macrophages were polarised in vitro, and their conditioned medium or cytokine-enriched medium containing specific macrophage-secreted factors was added to fibroblast-populated reconstituted collagen tissues.

Results: Macrophage-conditioned media led to changes in fibroblast-induced tissue compaction for all macrophage subsets. The presence of macrophage polarising factors in the conditioned medium, particularly LPS/IFNγ, and high serum levels directly affected tissue compaction and matrix remodelling gene expression. Without these confounding factors, M1 cytokine-enriched medium led to reduced tissue compaction when compared to M2a/M2c cytokine-enriched media. MMP activity analysis showed that matrix degradation likely contributed to tissue compaction.

Conclusion: Factors secreted by M1 macrophages resulted in reduced tissue compaction compared to M2a/M2c macrophages in an in vitro model of tissue remodelling, suggesting a diminished capacity for fibroblasts to remodel the extracellular matrix. Importantly, factors to polarize macrophages and serum are regarded as confounding factors in studying the effect of paracrine signalling by macrophages on tissue remodelling.

Background: Endometrial damage is a critical factor contributing to infertility, particularly in women with refractory thin endometrium or intrauterine adhesions. Therefore, developing innovative therapeutic strategies for endometrial regeneration is essential. This study evaluates the regenerative potential of endometrial stromal cell (EMSC) injection and EMSC-loaded patch application in a mouse model with ethanol-induced endometrial damage.

Methods: A mouse model of endometrial damage was established using ethanol injection into the uterine horn. EMSCs were isolated, cultured, and either HA-injected into the damaged endometrium or transplanted via a small intestinal submucosa (SIS)-based EMSC patch. Histological analyses were performed to assess endometrial thickness, gland regeneration, and fibrosis reduction.

Results: Both EMSC injection and SIS-based EMSC patch engraftment promoted endometrial regeneration. However, the SIS-based EMSC patch group exhibited significant improvements in endometrial thickness, gland formation, and fibrosis reduction compared to the EMSC injection group.

Conclusions: This study demonstrates the superior regenerative potential of an SIS-based EMSC patch over direct EMSC injection for endometrial repair. The findings suggest that scaffold-assisted cell therapy could be a promising approach for treating endometrial damage-related infertility. Further studies are required to optimize this strategy for clinical applications.

Background: Muscle tissue engineering seeks to develop biomimetic scaffolds capable of restoring or replacing damaged muscle by promoting cell alignment, proliferation, and differentiation within a controlled microenvironment. This study presents a novel hybrid scaffold combining electrospun polycaprolactone (PCL) fibers with gelatin methacryloly (GelMA) hydrogel. The scaffold integrates the topographical guidance of aligned PCL fibers with the supportive 3D matrix of GelMA to promote muscle tissue formation.

Methods: Electrospun PCL fibers (random/aligned) were incorporated into GelMA hydrogel to form a composite scaffold. Fiber morphology and orientation were analyzed using scanning electron microscopy (SEM), and surface modification of PCL fibers following plasma treatment was confirmed via Fourier transform infrared (FTIR) spectroscopy. Mechanical properties were assessed through tensile testing, and viscoelastic behavior was evaluated via rheometry. Cell viability and proliferation were assessed using live/dead and metabolic assays. Myogenic differentiation was evaluated by immunofluorescence staining of myosin heavy chain 2 (MYH2), and myotube formation was quantified by fusion index.

Results: Aligned PCL fibers significantly enhanced scaffold mechanics, with tensile strength and Young's modulus increasing five- and six-fold, respectively, compared to randomly oriented fibers. The fiber-reinforced GelMA scaffold showed a 45-fold increase in storage modulus (G') relative to GelMA alone. Enhanced cell viability and proliferation were observed. F-actin staining confirmed cell alignment along the fiber axis. MYH2 expression indicated improved myogenic differentiation, with the highest fusion index reaching 34.3%.

Conclusion: The PCL/GelMA hybrid scaffold exhibits excellent mechanical and biological performance, highlighting its potential for skeletal muscle tissue regeneration.