Tissue engineering and regenerative medicine最新文献

Background:

The derivation of salivary gland (SG) progenitors from pluripotent stem cells (PSCs) presents significant potential for developmental biology and regenerative medicine. However, the existing protocols for inducing SG include limited factors, making it challenging to mimic the in vivo microenvironment of embryonic SGs.

Methods:

We reported a cocktail factor approach to promote the differentiation of mouse embryonic stem cell (mESC)-derived oral epithelium (OE) into SG progenitors through a three-dimensional co-culture method. Upon confirming that the embryonic SG can promote the differentiation of mESC-derived OE, we performed RNA sequence analysis to identify factors involved in the differentiation of SG progenitors.

Results:

Our findings highlight several efficient pathways related to SG development, with frequent appearances of four factors: IFN-γ, TGF-β2, EGF, and IGF-1. The combined treatment using these cocktail factors increased the expression of key SG progenitor markers, including Sox9, Sox10, Krt5, and Krt14. However, absence of any one of these cocktail factors did not facilitate differentiation. Notably, aggregates treated with the cocktail factor formed SG epithelial-like structures and pre-bud-like structures on the surface.

Conclusion:

In conclusion, this study offers a novel approach to developing a differentiation protocol that closely mimics the in vivo microenvironment of embryonic SGs. This provides a foundation for generating PSC-derived organoids with near-physiological cell behaviors and structures.

Background:

Dysregulation of skin metabolism is associated with a plethora of diseases such as psoriasis and dermatitis. Until now, reconstructed human skin (RhS) models lack the metabolic potential of native human skin, thereby limiting their relevance to study human healthy and diseased skin. We aimed to determine whether incorporation of an adipocyte-containing hypodermis into RhS improves its metabolic potential and to identify major metabolic pathways up-regulated in adipose-RhS.

Methods:

Primary human keratinocytes, fibroblasts and differentiated adipose-derived stromal cells were co-cultured in a collagen/fibrin scaffold to create an adipose-RhS. The model was extensively characterized structurally in two- and three-dimensions, by cytokine secretion and RNA-sequencing for metabolic enzyme expression.

Results:

Adipose-RhS showed increased secretion of adipokines. Both RhS and adipose-RhS expressed 29 of 35 metabolic genes expressed in ex vivo native human skin. Addition of the adipose layer resulted in up-regulation of 286 genes in the dermal-adipose fraction of which 7 were involved in phase I (CYP19A1, CYP4F22, CYP3A5, ALDH3B2, EPHX3) and phase II (SULT2B1, GPX3) metabolism. Vitamin A, D and carotenoid metabolic pathways were enriched. Additionally, pro-inflammatory (IL-1β, IL-18, IL-23, IL-33, IFN-α2, TNF-α) and anti-inflammatory cytokine (IL-10, IL-12p70) secretion was reduced in adipose-RhS.

Conclusions:

Adipose-RhS mimics healthy native human skin more closely than traditional RhS since it has a less inflamed phenotype and a higher metabolic activity, indicating the contribution of adipocytes to tissue homeostasis. Therefore it is better suited to study onset of skin diseases and the effect of xenobiotics.

BACKGROUND:

Previous investigations have shown that local application of nanoparticles presenting the carbohydrate moiety galactose-α-1,3-galactose (α-gal epitopes) enhance wound healing by activating the complement system and recruiting pro-healing macrophages to the injury site. Our companion in vitro paper suggest α-gal epitopes can similarly recruit and polarize human microglia toward a pro-healing phenotype. In this continuation study, we investigate the in vivo implications of α-gal nanoparticle administration directly to the injured spinal cord.

METHODS:

α-Gal knock-out (KO) mice subjected to spinal cord crush were injected either with saline (control) or with α-gal nanoparticles immediately following injury. Animals were assessed longitudinally with neurobehavioral and histological endpoints.

RESULTS:

Mice injected with α-gal nanoparticles showed increased recruitment of anti-inflammatory macrophages to the injection site in conjunction with increased production of anti-inflammatory markers and a reduction in apoptosis. Further, the treated group showed increased axonal infiltration into the lesion, a reduction in reactive astrocyte populations and increased angiogenesis. These results translated into improved sensorimotor metrics versus the control group.

CONCLUSIONS:

Application of α-gal nanoparticles after spinal cord injury (SCI) induces a pro-healing inflammatory response resulting in neuroprotection, improved axonal ingrowth into the lesion and enhanced sensorimotor recovery. The data shows α-gal nanoparticles may be a promising avenue for further study in CNS trauma.

Graphical abstract

Putative mechanism of therapeutic action by α-gal nanoparticles. A. Nanoparticles injected into the injured cord bind to anti-Gal antibodies leaked from ruptured capillaries. The binding of anti-Gal to α-gal epitopes on the α-gal nanoparticles activates the complement system to release complement cleavage chemotactic peptides such as C5a, C3a that recruit macrophages and microglia. These recruited cells bind to the anti-Gal coated α-gal nanoparticles and are further polarized into the M2 state. B. Recruited M2 macrophages and microglia secrete neuroprotective and pro-healing factors to promote tissue repair, neovascularization and axonal regeneration (C.).

Background: To enhance articular cartilage healing, microfractures (Mfx) and bone marrow aspirate concentrate (BMAC) are commonly used, and some form of scaffold is often used together to increase its efficacy. Herein, we compared the efficacy of atelocollagen scaffold to that of collagen scaffold when used with Mfx or BMAC on osteochondral defect of animal.

Methods: This experiment was designed in two stages, and therapeutic effects of Mfx and BMAC were respectively evaluated when used with atelocollagen or collagen scaffold. Femoral condyle defects were artificially created in male New Zealand White rabbits, and in each stage, 12 rabbits were randomly allocated into three treatment groups: test group with additional atelocollagen scaffold, the positive control group with collagen scaffold, and the negative control group. Then, for 12 weeks, macroscopic and histological evaluations were performed.

Results: At 12 weeks, defects in the test group were fully regenerated with normal cartilage-like tissue, and were well integrated with the surrounding cartilage at both stages experiment, whereas defects in the control groups were not fully filled with regenerated tissue, and the tissue appeared as fibrous tissue. Histologically, the regenerated tissue in the test group showed a statistically significant improvement compared to the positive and negative control groups, achieving a similar structure as normal articular cartilage.

Conclusion: The results showed that implantation of the atelocollagen scaffold enhanced cartilage regeneration following osteochondral defects in rabbits. This suggests that the atelocollagen scaffold can be used with Mfx or BMAC for effective regeneration of osteochondral defects.

Background: Current tendon and ligament reconstruction surgeries rely on scar tissue healing which differs from native bone-to-tendon interface (BTI) tissue. We aimed to engineer Synovium-derived mesenchymal stem cells (Sy-MSCs) based scaffold-free fibrocartilage constructs and investigate in vivo bone-tendon interface (BTI) healing efficacy in a rat anterior cruciate ligament (ACL) reconstruction model.

Methods: Sy-MSCs were isolated from knee joint of rats. Scaffold-free sy-MSC constructs were fabricated and cultured in differentiation media including  TGF-β-only, CTGF-only, and TGF-β + CTGF. Collagenase treatment on tendon grafts was optimized to improve cell-to-graft integration. The effects of fibrocartilage differentiation and collagenase treatment on BTI integration was assessed by conducting histological staining, cell adhesion assay, and tensile testing. Finally, histological and biomechanical analyses were used to evaluate in vivo efficacy of fibrocartilage construct in a rat ACL reconstruction model.

Results: Fibrocartilage-like features were observed with in the scaffold-free sy-MSC constructs when applying TGF-β and CTGF concurrently. Fifteen minutes collagenase treatment increased cellular attachment 1.9-fold compared to the Control group without affecting tensile strength. The failure stress was highest in the Col + D + group (22.494 ± 13.74 Kpa) compared to other groups at integration analysis in vitro. The ACL Recon + FC group exhibited a significant 88% increase in estimated stiffness (p = 0.0102) compared to the ACL Recon group at the 4-week postoperative period.

Conclusion: Scaffold-free, fibrocartilage engineering together with tendon collagenase treatment enhanced fibrocartilaginous BTI healing in ACL reconstruction.

Background: The addition of growth factiors is commonly applied to improve the osteogenic differentiation of stem cells. However, for human pluripotent stem cells (hPSCs), their complex differentiation processes result in the unknown effect at different stages. In this study, we focused on the widely used bone forming peptide-1 (BFP-1) and investigated the effect and mechanisms of its addition on the osteogenic induction of hPSCs as a function of the supplementation period.

Methods: Monolayer-cultured hPSCs were cultured in osteogenic induction medium for 28 days, and the effect of BFP-1 peptide addition at varying weeks was examined. After differentiation for varying days (0, 7, 14, 21 and 28), the differentiation efficiency was determined by RT-PCR, flow cytometry, immunofluorescence, and alizarin red staining assays. Moreover, the expression of marker genes related to germ layers and epithelial-mesenchymal transition (EMT) was investigated at day 7.

Results: Peptide treatment during the first week promoted the generation of mesoderm cells and mesenchymal-like cells from hiPSCs. Then, the upregulated expression of osteogenesis marker genes/proteins was detected in both hESCs and hiPSCs during subsequent inductions with BFP-1 peptide treatment. Fortunately, further experimental design confirmed that treating the BFP-1 peptide during 7-21 days showed even better performance for hESCs but was ineffective for hiPSCs.

Conclusion: The differentiation efficiency of cells could be improved by determining the optimal treatment period. Our study has great value in maximizing the differentiation of hPSCs by adding osteogenesis peptides based on the revealed mechanisms and promoting the application of hPSCs in bone tissue regeneration.

Background: Regeneration is a highly complex process that requires the coordination of numerous molecular events, and identifying the key ruler that governs is important to investigate. While it has been shown that TCTP is a multi-functional protein that regulates cell proliferation, differentiation, apoptosis, anti-apoptosis, stem cell maintenance, and immune responses, but only a few studies associated to regeneration have been reported. To investigate the multi-functional role of TCTP in regeneration, the earthworm Perionyx excavatus was chosen.

Methods: Through pharmacological suppression of TCTP, amputation, histology, molecular docking, and western blotting, the multi-function role of TCTP involved in regeneration is revealed.

Results: Amputational studies show that P. excavatus is a clitellum-independent regenerating earthworm resulting in two functional worms upon amputation. Arresting cell cycle at the G1/S boundary using 2 mM Thymidine confirms that P. excavatus execute both epimorphosis and morphallaxis regeneration mode. The pharmacological suppression of TCTP using buclizine results in regeneration suppression. Following the combinatorial injection of 2 mM Thymidine and buclizine, the earthworm regeneration is completely blocked, which suggests a critical functional role of TCTP in morphallaxis. The pharmacological inhibition of TCTP also suppresses the key proteins involved in regeneration: Wnt3a (stem cell marker), PCNA (cell proliferation) and YAP1 (Hippo signalling) but augments the expression of cellular stress protein p53.

Conclusion: The collective results indicate that TCTP synchronously is involved in the process of stem cell activation, cell proliferation, morphallaxis, and organ development in the regeneration event.

Background: The skin, a vital organ protecting against microorganisms and dehydration, undergoes structural decline with aging, leading to visible issues such as wrinkles and sagging. Reduced blood vessels exacerbate vulnerability, hindering optimal cellular function and compromising skin health. Polydioxanone (PDO) biomaterials address aging concerns but produce acidic byproducts, causing inflammation. Inorganic particles and nitric oxide (NO) play crucial roles in inhibiting inflammation and promoting skin regeneration. Stem cell-derived extracellular vesicles (EVs) contribute to intercellular communication, offering the potential to enhance cell functions. The study proposes a method to enhance PDO-based medical devices by incorporating inorganic particles and immobilizing EVs, focusing on facial rejuvenation, anti-inflammatory response, collagen formation, and angiogenesis.

Method: PDO composites with inorganic particles such as magnesium hydroxide (MH) and zinc oxide (ZO) were prepared and followed by EV immobilization. Comprehensive characterization included biocompatibility, anti-inflammation, collagen formation ability, and angiogenesis ability.

Results: Bulk-modified PDO composites demonstrated even dispersion of inorganic particles, pH neutralization, and enhanced biocompatibility. EVs immobilized on the composite surface exhibited spherical morphology. Inflammation-related gene expressions decreased, emphasizing anti-inflammatory effects. Collagen-related gene and protein expressions increased, showcasing collagen formation ability. In addition, angiogenic capabilities were notably improved, indicating potential for skin rejuvenation.

Conclusion: The study successfully developed and characterized PDO composites with inorganic particles and EVs, demonstrating promising attributes for medical applications. These composites exhibit biocompatibility, anti-inflammatory properties, collagen formation ability, and angiogenic potential, suggesting their utility in skin rejuvenation and tissue engineering. Further research and clinical validation are essential.

Background: Rheumatoid arthritis (RA) is characterized by chronic inflammation and joint damage. Methotrexate (MTX), a commonly used disease-modifying anti-rheumatic drug (DMARD) used in RA treatment. However, the continued use of DMARDs can cause adverse effects and result in limited therapeutic efficacy. Cartilage extracellular matrix (CECM) has anti-inflammatory and anti-vascular effects and promotes stem cell migration, adhesion, and differentiation into cartilage cells.

Methods: CECM was assessed the dsDNA, glycosaminoglycan, collagen contents and FT-IR spectrum of CECM. Furthermore, we determined the effects of CECM and MTX on cytocompatibility in the SW 982 cells and RAW 264.7 cells. The anti-inflammatory effects of CECM and MTX were assessed using macrophage cells. Finally, we examined the in vivo effects of CECM in combination with MTX on anti-inflammation control and cartilage degradation in collagen-induced arthritis model. Anti-inflammation control and cartilage degradation were assessed by measuring the serum levels of RA-related cytokines and histology.

Results: CECM in combination with MTX had no effect on SW 982, effectively suppressing only RAW 264.7 activity. Moreover, anti-inflammatory effects were enhanced when low-dose MTX was combined with CECM. In a collagen-induced arthritis model, low-dose MTX combined with CECM remarkably reduced RA-related and pro-inflammatory cytokine levels in the blood. Additionally, low-dose MTX combined with CECM exerted the best cartilage-preservation effects compared to those observed in the other therapy groups.

Conclusion: Using CECM as an adjuvant in RA treatment can augment the therapeutic effects of MTX, reduce existing drug adverse effects, and promote joint tissue regeneration.

Background: Poly (lactic acid) (PLA) is a biodegradable polyester that has been exploited for a variety of biomedical applications, including tissue engineering. The incorporation of β-tricalcium phosphate (TCP) into PLA has imparted bioactivity to the polymeric matrix.

Methods: We have modified a 90%PLA-10%TCP composite with SiO₂ and MgO (1, 5 and 10 wt%), separately, to further enhance the material bioactivity. Filaments were prepared by extrusion, and scaffolds were fabricated using 3D printing technology associated with fused filament fabrication.

Results: The PLA-TCP-SiO₂ composites presented similar structural, thermal, and rheological properties to control PLA and PLA-TCP. In contrast, the PLA-TCP-MgO composites displayed absence of crystallinity, lower polymeric molecular weight, accelerated degradation ratio, and decreased viscosity within the 3D printing shear rate range. SiO₂ and MgO particles were homogeneously dispersed within the PLA and their incorporation increased the roughness and protein adsorption of the scaffold, compared to a PLA-TCP scaffold. This favorable surface modification promoted cell proliferation, suggesting that SiO₂ and MgO may have potential for enhancing the bio-integration of scaffolds in tissue engineering applications. However, high loads of MgO accelerated the polymeric degradation, leading to an acid environment that imparted the composite biocompatibility. The presence of SiO₂ stimulated mesenchymal stem cells differentiation towards osteoblast; enhancing extracellular matrix mineralization, alkaline phosphatase (ALP) activity, and bone-related genes expression.

Conclusion: The PLA-10%TCP-10%SiO₂ composite presented the most promising results, especially for bone tissue regeneration, due to its intense osteogenic behavior. PLA-10%TCP-10%SiO₂ could be used as an alternative implant for bone tissue engineering application.