Human Amniotic Mesenchymal Stem Cell Sheets Encapsulating Cartilage Particles Facilitate Repair of Rabbit Osteochondral Defects

RGDSP-functionalized peptide hydrogel stimulates growth factor secretion via integrin αv/PI3K/AKT axis for improved wound healing by human amniotic mesenchymal stem cells

The wound healing process involves communication among growth factors, cytokines, signaling pathways, and cells in the extracellular matrix, with growth factors acting as key regulators. Although stem cells can promote wound healing by secreting diverse growth factors, their therapeutic potential is hindered by poor survival and engraftment. Mimicking the stem cell-matrix interactions can improve stem cell survival, regulate their fate, and even enhance their paracrine effects. This study investigated the use of composite RGDmix hydrogel, which can support the survival and proliferation of human amniotic mesenchymal stem cells (hAMSCs), and effectively increase the expression of various growth factors, thereby promoting wound re-epithelialization, angiogenesis, and epidermal maturation. At last, the specific role of integrin αv and PI3K/AKT signaling pathways in the secretion of growth factors were examined by silencing them in vitro and in vivo. Results suggested that the RGDmix hydrogel improved the secretion of growth factors by hAMSCs through the RGDSP/integrin αv/PI3K/AKT axis, thereby enhancing the therapeutic effect in wound healing.

A Systematic Review of Human Amnion Enhanced Cartilage Regeneration in Full-Thickness Cartilage Defects

Cartilage defects present a significant challenge in orthopedic medicine, often leading to pain and functional impairment. To address this, human amnion, a naturally derived biomaterial, has gained attention for its potential in enhancing cartilage regeneration. This systematic review aims to evaluate the efficacy of human amnion in enhancing cartilage regeneration for full-thickness cartilage defects. An electronic search was conducted on MEDLINE-PubMed, Web of Science (WoS), and the Scopus database up to 27 December 2023 from 2007. A total of 401 articles were identified. After removing 125 duplicates and excluding 271 articles based on predetermined criteria, only 5 articles remained eligible for inclusion in this systematic review. All five eligible articles conducted in vivo studies utilizing rabbits as subjects. Furthermore, analysis of the literature reveals an increasing trend in the frequency of utilizing human amnion for the treatment of cartilage defects. Various forms of human amnion were utilized either alone or seeded with cells prior to implantation. Histological assessments and macroscopic observations indicated usage of human amnion improved cartilage repair outcomes. All studies highlighted the positive results despite using different forms of amnion tissues. This systematic review underscores the promising role of human amnion as a viable option for enhancing cartilage regeneration in full-thickness cartilage defects, thus offering valuable insights for future research and clinical applications in orthopedic tissue engineering.

Stem-Cell-Driven Chondrogenesis: Perspectives on Amnion-Derived Cells

Regenerative medicine harnesses stem cells' capacity to restore damaged tissues and organs. In vitro methods employing specific bioactive molecules, such as growth factors, bio-inductive scaffolds, 3D cultures, co-cultures, and mechanical stimuli, steer stem cells toward the desired differentiation pathways, mimicking their natural development. Chondrogenesis presents a challenge for regenerative medicine. This intricate process involves precise modulation of chondro-related transcription factors and pathways, critical for generating cartilage. Cartilage damage disrupts this process, impeding proper tissue healing due to its unique mechanical and anatomical characteristics. Consequently, the resultant tissue often forms fibrocartilage, which lacks adequate mechanical properties, posing a significant hurdle for effective regeneration. This review comprehensively explores studies showcasing the potential of amniotic mesenchymal stem cells (AMSCs) and amniotic epithelial cells (AECs) in chondrogenic differentiation. These cells exhibit innate characteristics that position them as promising candidates for regenerative medicine. Their capacity to differentiate toward chondrocytes offers a pathway for developing effective regenerative protocols. Understanding and leveraging the innate properties of AMSCs and AECs hold promise in addressing the challenges associated with cartilage repair, potentially offering superior outcomes in tissue regeneration.

Recent Advances in Cell Sheet-Based Tissue Engineering for Bone Regeneration

In conventional bone tissue engineering, cells are seeded onto scaffolds to create three-dimensional (3D) tissues, but the cells on the scaffolds are unable to effectively perform their physiological functions due to their low density and viability. Cell sheet (CS) engineering is expected to be free from this limitation. CS engineering uses the principles of self-assembly and self-organization of endothelial and mesenchymal stem cells to prepare CSs as building blocks for engineering bone grafts. This process recapitulates the native tissue development, thus attracting significant attention in the field of bone regeneration. However, the method is still in the prebasic experimental stage in bone defect repair. To make the method clinically applicable and valuable in personalized and precision medicine, current research is focused on the preparation of multifunctionalized building blocks using CS technologies, such as 3D layered CSs containing microvascular structures. Considering the great potential of CS engineering in repairing bone defects, in this review, the types of cell technologies are first outlined. We then summarize the various types of CSs as building blocks for engineering bone grafts. Furthermore, the specific applications of CSs in bone repair are discussed. Finally, we present specific suggestions for accelerating the application of CS engineering in the clinical treatment of bone defects.

Protecting the regenerative environment: selecting the optimal delivery vehicle for cartilage repair-a narrative review

Focal cartilage defects are common in youth and older adults, cause significant morbidity and constitute a major risk factor for developing osteoarthritis (OA). OA is the most common musculoskeletal (MSK) disease worldwide, resulting in pain, stiffness, loss of function, and is currently irreversible. Research into the optimal regenerative approach and methods in the setting of either focal cartilage defects and/or OA holds to the ideal of resolving both diseases. The two fundamentals required for cartilage regenerative treatment are 1) the biological element contributing to the regeneration (e.g., direct application of stem cells, or of an exogenous secretome), and 2) the vehicle by which the biological element is suspended and delivered. The vehicle provides support to the regenerative process by providing a protective environment, a structure that allows cell adherence and migration, and a source of growth and regenerative factors that can activate and sustain regeneration. Models of cartilage diseases include osteochondral defect (OCD) (which usually involve one focal lesion), or OA (which involves a more diffuse articular cartilage loss). Given the differing nature of these models, the optimal regenerative strategy to treat different cartilage diseases may not be universal. This could potentially impact the translatability of a successful approach in one condition to that of the other. An analogy would be the repair of a pothole (OCD) versus repaving the entire road (OA). In this narrative review, we explore the existing literature evaluating cartilage regeneration approaches for OCD and OA in animal then in human studies and the vehicles used for each of these two conditions. We then highlight strengths and challenges faced by the different approaches presented and discuss what might constitute the optimal cartilage regenerative delivery vehicle for clinical cartilage regeneration.

Comparison of allogeneic mesenchymal stem cells therapeutic potentials in rabbits' cartilage defects: Μacroscopic and histological outcomes

Mesenchymal stem cells are safe and effective for treating joint injuries. However, the most suitable cell source remains controversial. This randomized controlled, double-blind study aimed to evaluate the potentials of rabbit allogeneic bone marrow- (BMSCs), adipose- (ASCs) and synovial membrane- (SDSCs) derived stem cells encapsulated in fibrin glue (FG) in vivo. The therapeutic properties of fibrin glue in critical-sized osteochondral defects (ODs) were also investigated. A 3 × 3 mm-sized OD was created in the femoral patellar groove on both knees of New Zealand rabbits, except from the left knees of the control group in which the OD was 2 × 3mm. The rabbits were randomly divided into four groups (right/left knee): 3 × 3 mm / 2 × 3 mm-sized OD control group, FG/FG with ASCs group, FG/FG with BMSCs group, FG/FG with SDSCs group. The International Cartilage Repair Society (ICRS) and the O'Driscoll scales were used to evaluate tissue characteristics after 12 weeks. FG promoted the production of reparative tissue with superior macroscopic features. Allogeneic MSCs combined with FG improved the macroscopic and histological scores more than the FG groups. The tissue in the SDSCs group was macroscopically and histologically better than the ASCs and BMSCs groups. The ICRS score differed among the SDSCs and the ASCs groups, while the empty critical-sized ODs were filled with inferior tissue compared to smaller ones. The preclinical feasibility of stem cells for OD regeneration in rabbits and the osteochondrogenic superiority of SDSCs was demonstrated. Additional tests and extended studies are required to reassure the long-term safety of these findings.

BMP-2 Genome-Edited Human MSCs Protect against Cartilage Degeneration via Suppression of IL-34 in Collagen-Induced Arthritis

Even though the regenerative potential of mesenchymal stem cells (MSCs) has been extensively studied, there is a debate regarding their minimal therapeutic properties. Bone morphogenetic proteins (BMP) are involved in cartilage metabolism, chondrogenesis, and bone healing. In this study, we aimed to analyze the role of genome-edited BMP-2 overexpressing amniotic mesenchymal stem cells (AMMs) in a mouse model of collagen-induced arthritis (CIA). The BMP-2 gene was synthesized and inserted into AMMs using transcription activator-like effector nucleases (TALENs), and BMP-2-overexpressing AMMs (AMM/B) were sorted and characterized using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The co-culture of AMM/B with tumor necrosis factor (TNF)-α-treated synovial fibroblasts significantly decreased the levels of interleukin (IL)-34. The therapeutic properties of AMM/B were evaluated using the CIA mouse model. The injection of AMM/B attenuated CIA progression and inhibited T helper (Th)17 cell activation in CIA mice. In addition, the AMM/B injection increased proteoglycan expression in cartilage and decreased the infiltration of inflammatory cells and factors, including IL-1β, TNF-α, cyclooxygenase (COX)-2, and Nuclear factor kappa B (NF-kB) in the joint tissues. Therefore, editing the BMP-2 genome in MSCs might be an alternative strategy to enhance their therapeutic potential for treating cartilage degeneration in arthritic joints.

The preclinical and clinical progress of cell sheet engineering in regenerative medicine

Cell therapy is an accessible method for curing damaged organs or tissues. Yet, this approach is limited by the delivery efficiency of cell suspension injection. Over recent years, biological scaffolds have emerged as carriers of delivering therapeutic cells to the target sites. Although they can be regarded as revolutionary research output and promote the development of tissue engineering, the defect of biological scaffolds in repairing cell-dense tissues is apparent. Cell sheet engineering (CSE) is a novel technique that supports enzyme-free cell detachment in the shape of a sheet-like structure. Compared with the traditional method of enzymatic digestion, products harvested by this technique retain extracellular matrix (ECM) secreted by cells as well as cell-matrix and intercellular junctions established during in vitro culture. Herein, we discussed the current status and recent progress of CSE in basic research and clinical application by reviewing relevant articles that have been published, hoping to provide a reference for the development of CSE in the field of stem cells and regenerative medicine.

Cell Sheet Technology as an Engineering-Based Approach to Bone Regeneration

Bone defects that are congenital or the result of infection, malignancy, or trauma represent a challenge to the global healthcare system. To address this issue, multiple research groups have been developing novel cell sheet technology (CST)-based approaches to promote bone regeneration. These methods hold promise for use in regenerative medicine because they preserve cell-cell contacts, cell-extracellular matrix interactions, and the protein makeup of cell membranes. This review introduces the concept and preparation system of the cell sheet (CS), explores the application of CST in bone regeneration, highlights the current states of the bone regeneration via CST, and offers perspectives on the challenges and future research direction of translating current knowledge from the lab to the clinic.

Human acellular amniotic membrane scaffolds encapsulating juvenile cartilage fragments accelerate the repair of rabbit osteochondral defects

Aims

The purpose of this study was to explore a simple and effective method of preparing human acellular amniotic membrane (HAAM) scaffolds, and explore the effect of HAAM scaffolds with juvenile cartilage fragments (JCFs) on osteochondral defects.

Methods

HAAM scaffolds were constructed via trypsinization from fresh human amniotic membrane (HAM). The characteristics of the HAAM scaffolds were evaluated by haematoxylin and eosin (H&E) staining, picrosirius red staining, type II collagen immunostaining, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Human amniotic mesenchymal stem cells (hAMSCs) were isolated, and stemness was verified by multilineage differentiation. Then, third-generation (P3) hAMSCs were seeded on the HAAM scaffolds, and phalloidin staining and SEM were used to detect the growth of hAMSCs on the HAAM scaffolds. Osteochondral defects (diameter: 3.5 mm; depth: 3 mm) were created in the right patellar grooves of 20 New Zealand White rabbits. The rabbits were randomly divided into four groups: the control group (n = 5), the HAAM scaffolds group (n = 5), the JCFs group (n = 5), and the HAAM + JCFs group (n = 5). Macroscopic and histological assessments of the regenerated tissue were evaluated to validate the treatment results at 12 weeks.

Results

In vitro, the HAAM scaffolds had a network structure and possessed abundant collagen. The HAAM scaffolds had good cytocompatibility, and hAMSCs grew well on the HAAM scaffolds. In vivo, the macroscopic scores of the HAAM + JCFs group were significantly higher than those of the other groups. In addition, histological assessments demonstrated that large amounts of hyaline-like cartilage formed in the osteochondral defects in the HAAM + JCFs group. Integration with surrounding normal cartilage and regeneration of subchondral bone in the HAAM + JCFs group were better than those in the other groups.

Conclusion

HAAM scaffolds combined with JCFs promote the regenerative repair of osteochondral defects.

Cite this article: Bone Joint Res 2022;11(6):349–361.

Integrated regulation of chondrogenic differentiation in mesenchymal stem cells and differentiation of cancer cells

Chondrogenesis is the formation of chondrocytes and cartilage tissues and starts with mesenchymal stem cell (MSC) recruitment and migration, condensation of progenitors, chondrocyte differentiation, and maturation. The chondrogenic differentiation of MSCs depends on co-regulation of many exogenous and endogenous factors including specific microenvironmental signals, non-coding RNAs, physical factors existed in culture condition, etc. Cancer stem cells (CSCs) exhibit self-renewal capacity, pluripotency and cellular plasticity, which have the potential to differentiate into post-mitotic and benign cells. Accumulating evidence has shown that CSCs can be induced to differentiate into various benign cells including adipocytes, fibrocytes, osteoblast, and so on. Retinoic acid has been widely used in the treatment of acute promyelocytic leukemia. Previous study confirmed that polyploid giant cancer cells, a type of cancer stem-like cells, could differentiate into adipocytes, osteocytes, and chondrocytes. In this review, we will summarize signaling pathways and cytokines in chondrogenic differentiation of MSCs. Understanding the molecular mechanism of chondrogenic differentiation of CSCs and cancer cells may provide new strategies for cancer treatment.

Recent Biomimetic Approaches for Articular Cartilage Tissue Engineering and Their Clinical Applications: Narrative Review of the Literature

Since articular cartilage is lacking blood vessels and nerves, its capacity to heal is extremely limited. This means that ruptured cartilage affects the joint as a whole. A health issue known as osteoarthritis can develop as a result of injury and deterioration. Osteoarthritis development can be speeded up by the widespread deterioration of articular cartilage, which ranks third on the list of musculoskeletal disorders requiring rehabilitation, behind only low back pain and broken bones. The current treatments for cartilage repair are ineffective and rarely restore full function or tissue normalcy. A promising new technology in tissue engineering may help create functional cartilage tissue substitutes. Ensuring that the cell source is loaded with bioactive molecules that promote cellular differentiation and/or maturation is the general approach. This review summarizes recent advances in cartilage tissue engineering, and recent clinical trials have been conducted to provide a comprehensive overview of the most recent research developments and clinical applications in the framework of degenerated articular cartilage and osteoarthritis.

hAMSC Sheet Promotes Repair of Rabbit Osteochondral Defects

Osteochondral lesion is clinically common disease, which has been recognized as one of the contributing factors of significant morbidity. Although current treatments have achieved good outcomes, some undesirable complications and failures are not uncommon. Cell sheet technology (CST), an innovative technology to harvest seed cells and preserve abundant ECM, has been widely used in various tissue regeneration. For osteochondral lesion, many studies focus on using CST to repair osteochondral lesion and have achieved good outcomes. In the previous study, we have demonstrated that hAMSC sheet had a positive effect on osteochondral lesion. Therefore, this study is aimed at comparing the effect of noninduced hAMSC sheet with chondrogenically induced hAMSC sheet on osteochondral lesion and cartilage regeneration.

Current Advances in the Regeneration of Degenerated Articular Cartilage: A Literature Review on Tissue Engineering and Its Recent Clinical Translation

Functional ability is the basis of healthy aging. Articular cartilage degeneration is amongst the most prevalent degenerative conditions that cause adverse impacts on the quality of life; moreover, it represents a key predisposing factor to osteoarthritis (OA). Both the poor capacity of articular cartilage for self-repair and the unsatisfactory outcomes of available clinical interventions make innovative tissue engineering a promising therapeutic strategy for articular cartilage repair. Significant progress was made in this field; however, a marked heterogeneity in the applied biomaterials, biofabrication, and assessments is nowadays evident by the huge number of research studies published to date. Accordingly, this literature review assimilates the most recent advances in cell-based and cell-free tissue engineering of articular cartilage and also focuses on the assessments performed via various in vitro studies, ex vivo models, preclinical in vivo animal models, and clinical studies in order to provide a broad overview of the latest findings and clinical translation in the context of degenerated articular cartilage and OA.

The Application of Cartilage Tissue Engineering with Cell-Laden Hydrogel in Plastic Surgery: A Systematic Review

BACKGROUND

As a contour-supporting material, the cartilage has a significant application value in plastic surgery. Since the development of hydrogel scaffolds with sufficient biomechanical strength and high biocompatibility, cell-laden hydrogels have been widely studied for application in cartilage bioengineering. This systematic review summarizes the latest research on engineered cartilage constructed using cell-laden hydrogel scaffolds in plastic surgery.

METHODS

A systematic review was performed by searching the PubMed and Web of Science databases using selected keywords and Medical Subject Headings search terms.

RESULTS

Forty-two studies were identified based on the search criteria. After full-text screening for inclusion and exclusion criteria, 18 studies were included. Data collected from each study included culturing form, seed cell types and sources, concentration of cells and gels, scaffold materials and bio-printing structures, and biomechanical properties of cartilage constructs. These cell-laden hydrogel scaffolds were reported to show some feasibility of cartilage engineering, including better cell proliferation, enhanced deposition of glycosaminoglycans and collagen type II in the extracellular matrix, and better biomechanical properties close to the natural state.

CONCLUSION

Cell-laden hydrogels have been widely used in cartilage bioengineering research. Through 3-dimensional (3D) printing, the cell-laden hydrogel can form a bionic contour structure. Extracellular matrix expression was observed in vivo and in vitro, and the elastic modulus was reported to be similar to that of natural cartilage. The future direction of cartilage tissue engineering in plastic surgery involves the use of novel hydrogel materials and more advanced 3D printing technology combined with biochemistry and biomechanical stimulation.

Mechanical properties of cell sheets and spheroids: the link between single cells and complex tissues

Cell aggregates, including sheets and spheroids, represent a simple yet powerful model system to study both biochemical and biophysical intercellular interactions. However, it is becoming evident that, although the mechanical properties and behavior of multicellular structures share some similarities with individual cells, yet distinct differences are observed in some principal aspects. The description of mechanical phenomena at the level of multicellular model systems is a necessary step for understanding tissue mechanics and its fundamental principles in health and disease. Both cell sheets and spheroids are used in tissue engineering, and the modulation of mechanical properties of cell constructs is a promising tool for regenerative medicine. Here, we review the data on mechanical characterization of cell sheets and spheroids, focusing both on advances in the measurement techniques and current understanding of the subject. The reviewed material suggest that interplay between the ECM, intercellular junctions, and cellular contractility determines the behavior and mechanical properties of the cell aggregates.

TGF-β1 overexpressing human MSCs generated using gene editing show robust therapeutic potential for treating collagen-induced arthritis

Transforming growth factor β (TGF-β) plays a pivotal role in cartilage differentiation and other functions of mesenchymal stem cells (MSCs). In this study, we investigated the therapeutic potential of TGF-β1 overexpressing amniotic MSCs (AMMs) generated using gene editing in a mouse model of damaged cartilage. The TGF-β1 gene was inserted into a safe harbor genomic locus in AMMs using transcription activator-like effector nucleases. The chondrogenic properties of TGF-β1-overexpressing AMMs (AMM/T) were characterized using reverse transcription polymerase chain reaction (RT-PCR), quantitative RT-PCR, and histological analysis, and their therapeutic effects were evaluated in mouse model of collagen-induced arthritis (CIA). AMM/T expressed cartilage-specific genes and showed intense Safranin O and Alcian blue staining. Furthermore, injecting AMM/T attenuated CIA progression compared with AMM injection, and increased the regulatory T (Treg) cell population, while suppressing T helper (Th)17 cell activation in CIA mice. Proinflammatory factors, such as interleukin-1β (IL-1β), IL-6, monocyte chemoattractant protein-1, and tumor necrosis factor-α were significantly decreased in AMM/T injected CIA mice compared with their AMM injected counterparts. In conclusion, genome-edited AMMs overexpressing TGF-β1 may be a novel and alternative therapeutic option for protecting cartilage and treating inflammatory joint arthritis.

Biomimetic cell-adhesive ligand-functionalized peptide composite hydrogels maintain stemness of human amniotic mesenchymal stem cells

In vivo, stem cells reside in a three-dimensional (3D) extracellular microenvironment in which complicated biophysical and biochemical factors regulate their behaviors. Biomimicking of the stem cell-matrix interactions is an ideal approach for controlling the stem cell fate. This study investigates the effects of the incorporation of cell-adhesive ligands in 3D self-assembling peptide hydrogels to modulate stem cell survival, proliferation, maintenance of stemness, and osteogenic differentiation. The results show that the composite hydrogels were non-cytotoxic and effective for maintaining human amniotic mesenchymal stem cell (hAMSC) survival, proliferation and phenotypic characterization. The expression levels of pluripotent markers were also upregulated in the composite hydrogels. Under inductive media conditions, mineral deposition and mRNA expression levels of osteogenic genes of hAMSCs were enhanced. The increasing expression of integrin α- and β-subunits for hAMSCs indicates that the ligand-integrin interactions may modulate the cell fate for hAMSCs in composite hydrogels.

Tissue Engineering Strategies to Increase Osteochondral Regeneration of Stem Cells; a Close Look at Different Modalities

The homeostasis of osteochondral tissue is tightly controlled by articular cartilage chondrocytes and underlying subchondral bone osteoblasts via different internal and external clues. As a correlate, the osteochondral region is frequently exposed to physical forces and mechanical pressure. On this basis, distinct sets of substrates and physicochemical properties of the surrounding matrix affect the regeneration capacity of chondrocytes and osteoblasts. Stem cells are touted as an alternative cell source for the alleviation of osteochondral diseases. These cells appropriately respond to the physicochemical properties of different biomaterials. This review aimed to address some of the essential factors which participate in the chondrogenic and osteogenic capacity of stem cells. Elements consisted of biomechanical forces, electrical fields, and biochemical and physical properties of the extracellular matrix are the major determinant of stem cell differentiation capacity. It is suggested that an additional certain mechanism related to signal-transduction pathways could also mediate the chondro-osteogenic differentiation of stem cells. The discovery of these clues can enable us to modulate the regeneration capacity of stem cells in osteochondral injuries and lead to the improvement of more operative approaches using tissue engineering modalities.

Three-dimensional silk fibroin scaffolds enhance the bone formation and angiogenic differentiation of human amniotic mesenchymal stem cells: a biocompatibility analysis

Silk fibroin (SF) is a fibrous protein with unique mechanical properties, adjustable biodegradation, and the potential to drive differentiation of mesenchymal stem cells (MSCs) along the osteogenic lineage, making SF a promising scaffold material for bone tissue engineering. In this study, hAMSCs were isolated by enzyme digestion and identified by multiple-lineage differentiation. SF scaffold was fabricated by freeze-drying, and the adhesion and proliferation abilities of hAMSCs on scaffolds were determined. Osteoblast differentiation and angiogenesis of hAMSCs on scaffolds were further evaluated, and histological staining of calvarial defects was performed to examine the cocultured scaffolds. We found that hAMSCs expressed the basic surface markers of MSCs. Collagen type I (COL-I) expression was observed on scaffolds cocultured with hAMSCs. The scaffolds potentiated the proliferation of hAMSCs and increased the expression of COL-I in hAMSCs. The scaffolds also enhanced the alkaline phosphatase activity and bone mineralization, and upregulated the expressions of osteogenic-related factors in vitro. The scaffolds also enhanced the angiogenic differentiation of hAMSCs. The cocultured scaffolds increased bone formation in treating critical calvarial defects in mice. This study first demonstrated that the application of 3D SF scaffolds co-cultured with hAMSCs greatly enhanced osteogenic differentiation and angiogenesis of hAMSCs in vitro and in vivo. Thus, 3D SF scaffolds cocultured with hAMSCs may be a better alternative for bone tissue engineering.

Immunomodulatory Properties of Amniotic Membrane Derivatives and Their Potential in Regenerative Medicine

PURPOSE OF REVIEW

During the last decades, the field of regenerative medicine has been rapidly evolving. Major progress has been made in the development of biological substitutes applying the principles of cell transplantation, material science, and bioengineering.

RECENT FINDINGS

Among other sources, amniotic-derived products have been used for decades in various fields of medicine as a biomaterial for the wound care and tissue replacement. Moreover, human amniotic epithelial and mesenchymal cells have been intensively studied for their immunomodulatory capacities. Amniotic cells possess two major characteristics that have already been widely exploited. The first is their ability to modulate and suppress the innate and adaptive immunities, making them a true asset for chronic inflammatory disorders and for the induction of tolerance in transplantation models. The second is their multilineage differentiation capacity, offering a source of cells for tissue engineering. The latter combined with the use of amniotic membrane as a scaffold offers all components necessary to create an optimal environment for cell and tissue regeneration. This review summarizes beneficial properties of hAM and its derivatives and discusses their potential in regenerative medicine.

Effect of book-shaped acellular tendon scaffold with bone marrow mesenchymal stem cells sheets on bone-tendon interface healing

Background

Tissue engineering has exhibited great effect on treatment for bone-tendon interface (BTI) injury. The aim of this study was to evaluate the effect of a book-shaped acellular tendon scaffold (ATS) with bone marrow mesenchymal stem cells sheets (MSCS) for BTI injury repair.

Methods

ATS was designed based on the shape of "book", decellularization effect was evaluated by Hematoxylin and eosin (H&E), 4', 6-diamidino-2-phenylindole (DAPI) and scanning electron microscopy (SEM), then bone marrow mesenchymal stem cells (MSCs) were cultured on ATS to assess the differentiation inductivity of ATS. A rabbit right partial patellotomy model was established, and MSCS seeded on ATS were implanted into the lesion site. The patella-patellar tendon (PPT) at 2, 4, 8 or 16 weeks post-operation were obtained for histological, biomechanical and immunofluorescence analysis.

Results

H&E, DAPI and SEM results confirmed the efficiency of decellularization of ATS, and their in vitro tenogenic and chondrogenic ability were successfully identified. In vivo results showed increased macrophage polarization toward the M2 phenotype, IL-10 expression, regenerated bone and fibrocartilage at the patella-patellar tendon interface of animals received MSCS modified ATS implantation. In addition, the level of tensile strength was also the highest in MSCS modified ATS implantation group.

Conclusion

This study suggests that ATS combined with MSCS performed therapeutic effects on promoting the regeneration of cartilage layer and enhancing the healing quality of patella-patellar tendon interface.

The translational potential of this article

This study showed the good biocompatibility of the ATS, as well as the great efficacy of ATS with MSCS on tendon to bone healing. The results meant that the novel book-shaped ATS with MSCS may have a great potential for clinical application.

Human Amniotic Mesenchymal Stem Cells Promote Endogenous Bone Regeneration

Bone regeneration has become a research hotspot and therapeutic target in the field of bone and joint medicine. Stem cell-based therapy aims to promote endogenous regeneration and improves therapeutic effects and side-effects of traditional reconstruction of significant bone defects and disorders. Human amniotic mesenchymal stem cells (hAMSCs) are seed cells with superior paracrine functions on immune-regulation, anti-inflammation, and vascularized tissue regeneration. The present review summarized the source and characteristics of hAMSCs and analyzed their roles in tissue regeneration. Next, the therapeutic effects and mechanisms of hAMSCs in promoting bone regeneration of joint diseases and bone defects. Finally, the clinical application of hAMSCs from current clinical trials was analyzed. Although more studies are needed to confirm that hAMSC-based therapy to treat bone diseases, the clinical application prospect of the approach is worth investigating.