Feasibility of autologous bone marrow mesenchymal stem cell-derived extracellular matrix scaffold for cartilage tissue engineering

Development of a Biomimetic Hydrogel Based on Predifferentiated Mesenchymal Stem-Cell-Derived ECM for Cartilage Tissue Engineering

The use of decellularized extracellular matrix (dECM) as a biomaterial has been an important step forward for the development of functional tissue constructs. In addition to tissues and organs, cell cultures are gaining a lot of attention as an alternative source of dECM. In this work, a novel biomimetic hydrogel is developed based on dECM obtained from mesenchymal stem cells (mdECM) for cartilage tissue engineering. To this end, cells are seeded under specific culture conditions to generate an early chondrogenic extracellular matrix (ECM) providing cues and elements necessary for cartilage development. The composition is determined by quantitative, histological, and mass spectrometry techniques. Moreover, the decellularization process is evaluated by measuring the DNA content and compositional analyses, and the hydrogel is formulated at different concentrations (3% and 6% w/v). Results show that mdECM derived hydrogels possess excellent biocompatibility and suitable physicochemical and mechanical properties for their injectability. Furthermore, it is evidenced that this hydrogel is able to induce chondrogenesis of mesenchymal stem cells (MSCs) without supplemental factors and, furthermore, to form hyaline cartilage-like tissue after in vivo implantation. These findings demonstrate for the first time the potential of this hydrogel based on mdECM for applications in cartilage repair and regeneration.

Cell-Derived Extracellular Matrix for Tissue Engineering and Regenerative Medicine

Cell-derived extracellular matrices (CD-ECMs) captured increasing attention since the first studies in the 1980s. The biological resemblance of CD-ECMs to their in vivo counterparts and natural complexity provide them with a prevailing bioactivity. CD-ECMs offer the opportunity to produce microenvironments with costumizable biological and biophysical properties in a controlled setting. As a result, CD-ECMs can improve cellular functions such as stemness or be employed as a platform to study cellular niches in health and disease. Either on their own or integrated with other materials, CD-ECMs can also be utilized as biomaterials to engineer tissues de novo or facilitate endogenous healing and regeneration. This review provides a brief overview over the methodologies used to facilitate CD-ECM deposition and manufacturing. It explores the versatile uses of CD-ECM in fundamental research and therapeutic approaches, while highlighting innovative strategies. Furthermore, current challenges are identified and it is accentuated that advancements in methodologies, as well as innovative interdisciplinary approaches are needed to take CD-ECM-based research to the next level.

Cell-derived decellularized extracellular matrix scaffolds for articular cartilage repair

Articular cartilage repair remains a great clinical challenge. Tissue engineering approaches based on decellularized extracellular matrix (dECM) scaffolds show promise for facilitating articular cartilage repair. Traditional regenerative approaches currently used in clinical practice, such as microfracture, mosaicplasty, and autologous chondrocyte implantation, can improve cartilage repair and show therapeutic effect to some degree; however, the long-term curative effect is suboptimal. As dECM prepared by proper decellularization procedures is a biodegradable material, which provides space for regeneration tissue growth, possesses low immunogenicity, and retains most of its bioactive molecules that maintain tissue homeostasis and facilitate tissue repair, dECM scaffolds may provide a biomimetic microenvironment promoting cell attachment, proliferation, and chondrogenic differentiation. Currently, cell-derived dECM scaffolds have become a research hotspot in the field of cartilage tissue engineering, as ECM derived from cells cultured in vitro has many advantages compared with native cartilage ECM. This review describes cell types used to secrete ECM, methods of inducing cells to secrete cartilage-like ECM and decellularization methods to prepare cell-derived dECM. The potential mechanism of dECM scaffolds on cartilage repair, methods for improving the mechanical strength of cell-derived dECM scaffolds, and future perspectives on cell-derived dECM scaffolds are also discussed in this review.

Evaluation of an Autologous Bone Mesenchymal Stem Cell-Derived Extracellular Matrix Scaffold in a Rabbit and Minipig Model of Cartilage Repair

Background

This study aimed to evaluate an autologous bone mesenchymal stem cell (MSC)-derived extracellular matrix (ECM) scaffold in two animal models of cartilage repair.

Material/Methods

A rabbit model (n=16) and a minipig model (n=8) of cartilage repair were created with cartilage defects of the knee joints treated with bone marrow stimulation (BMS). In the ECM group, autologous bone MSC-derived ECM scaffolds were implanted into the cartilage defects after bone marrow stimulation. In the BMS group, the cartilage defects were treated by bone marrow stimulation only. The renewal capacity of bone MSCs was measured with a colony-forming unit fibroblast (CFU-F) in vitro assay. The extent of cartilage repair was as-sessed at 6 months after surgery.

Results

In the rabbit model, the macroscopic appearance of the exudate of the healing wounds in the ECM group showed less fibrosis, and the histology showed more evenly distributed chondrocytes compared with the BMS group. The CFU-F assay showed that the number of bone MSCs in the ECM group was approximately was twice that of the BMS group. In the minipig model, the macroscopic appearance and magnetic resonance imaging (MRI) findings of the ECM group were improved when compared with the BMS group. The repaired tissue in ECM group had similar histological characteristics and biochemical content to normal hyaline cartilage.

Conclusions

In two animal models of knee joint cartilage repair, the use of an ECM scaffold increased the number of bone MSCs and improved the extent of cartilage repair.

Applications of decellularized extracellular matrix in bone and cartilage tissue engineering

Regenerative therapies for bone and cartilage injuries are currently unable to replicate the complex microenvironment of native tissue. There are many tissue engineering approaches attempting to address this issue through the use of synthetic materials. Although synthetic materials can be modified to simulate the mechanical and biochemical properties of the cell microenvironment, they do not mimic in full the multitude of interactions that take place within tissue. Decellularized extracellular matrix (dECM) has been established as a biomaterial that preserves a tissue's native environment, promotes cell proliferation, and provides cues for cell differentiation. The potential of dECM as a therapeutic agent is rising, but there are many limitations of dECM restricting its use. This review discusses the recent progress in the utilization of bone and cartilage dECM through applications as scaffolds, particles, and supplementary factors in bone and cartilage tissue engineering.

Bone marrow stem cells-derived extracellular matrix is a promising material

The extracellular matrix(ECM), which is primarily composed of collagens and proteoglycans, plays a key role in cell proliferation, differentiation, and migration and interactions between cells. In this study, we produced chitosan/gelatin/bone marrow stem cells-derived extracellular matrix(C/G/BMSCs-dECM) scaffolds via lyophilization and cross-linking, and chitosan/gelatin(C/G) scaffolds were used as controls. For the C/G/BMSCs-dECM scaffolds, the average pore size was 289.17 ± 80.28 μm; the average porosity was 89.25 ± 3.75%; the average compressive modulus was 0.82 ± 0.07 MPa; and the average water uptake ratio was 13.81 ± 1.00. In vitro, the C/G/BMSCs-dECM scaffolds promoted bone marrow stem cells(BMSCs) attachment and proliferation. Moreover, improved osteogenic differentiation was observed for these scaffolds. Thus, C/G/BMSCs-dECM is a promising material for bone tissue engineering.

Adhesion, proliferation and osteogenic differentiation of mesenchymal stem cells in 3D printed poly-ε-caprolactone/hydroxyapatite scaffolds combined with bone marrow clots

Mesenchymal stem cells (MSCs), a stem cell population capable of multi‑lineage differentiation, bound to porous biomaterial scaffolds, are widely used for bone tissue regeneration. However, there is evidence to suggest that MSC collection from bone marrow and expansion in vitro may result in phenotypic changes including a loss of differentiation potential and cell senescence. The aim of the present study was to find a facile and efficient approach to enable MSC adhesion and proliferation to scaffolds with osteogenic differentiation. Unprocessed bone marrow blood from the condyle of the distal femur in the rabbits were added to three‑dimensional (3D) printed porous poly-ε-caprolactone/hydroxyapatite (PCL/HA) scaffolds with bone marrow clots (MC) formed, using two different methods for Group A (MC enriched scaffolds) and Group B (MC combined scaffolds), and then were cultured in osteogenic medium for 4 weeks. The scaffolds were assessed macroscopically and microscopically. Scaffold bioactivity and the proliferation and osteogenic differentiation of seeded MSCs were measured. Higher cellular viability and greater cell numbers in the scaffolds at later phases of culture were observed in Group B compared with Group A. In addition, Group B was associated with greater osteoinductivity, alkaline phosphatase activity and bony nodule formation, as assessed using scanning electron microscopy. Furthermore, reverse transcription‑quantitative polymerase chain reaction analysis revealed that more osteogenic differentiation was present in Group B, compared with Group A. MC combined scaffolds proved to be a highly efficient, reliable and simple novel method for MSC adhesion, proliferation and differentiation. The MC combined PCL‑HA multi‑scale porosity scaffold may represent a candidate for future bone regeneration studies.

Extracellular matrix powder from cultured cartilage-like tissue as cell carrier for cartilage repair

Cartilage extracellular matrix (ECM) is a promising material for cartilage repair because of its bioactivity. However, the animal source of ECM unavoidably increases the risk of pathogen infection and the variability of product quality. In this study, we utilized a novel 3D culture method to prepare a new type of artificial decellularized matrix powder (DEMP) for the development of injectable, bioactive, biodegradable cell carriers for cartilage tissue engineering. This culture method combined hanging drop culture with suspension culture method, and was very efficient to produce cartilage-like tissue (CLT). By this method, an initial 2.3 × 10⁶ chondrocyte generated as much as 58.22 mg wet weight CLT at two weeks, which proved to contain abundant glycoaminoglycans (GAGs), type II collagen, and BMP-2 and TGF-β1 growth factors by staining techniques and biochemical analysis. Subsequently, the two-week-old CLT was decellularized to prepare the artificial DEMP. In an in vitro study, it was found that MSCs cultured on DEMP differentiated to chondrocytes very well and secreted rich GAGs and type II collagen at three weeks even without exogenous TGF-β1. The in vivo study demonstrated that the DEMP not only facilitated regeneration of hyaline cartilage, which was implied by the intense staining of GAGs and type II collagen in rabbit subchondral defects at 1 month, but also benefited the regeneration of subchondral bone (bone ingrowth at 1 month: 48.22%) as shown in micro-CT data. Collectively, these results suggest that the artificial DEMP prepared by this culture method holds great potential as a novel ECM material for cartilage repair.

The host response to naturally-derived extracellular matrix biomaterials

Biomaterials based on natural materials including decellularized tissues and tissue-derived hydrogels are becoming more widely used for clinical applications. Because of their native composition and structure, these biomaterials induce a distinct form of the foreign body response that differs from that of non-native biomaterials. Differences include direct interactions with cells via preserved moieties as well as the ability to undergo remodeling. Moreover, these biomaterials could elicit adaptive immune responses due to the presence of modified native molecules. Therefore, these biomaterials present unique challenges in terms of understanding the progression of the foreign body response. This review covers this response to natural materials including natural polymers, decellularized tissues, cell-derived matrix, tissue derived hydrogels, and biohybrid materials. With the expansion of the fields of regenerative medicine and tissue engineering, the current repertoire of biomaterials has also expanded and requires continuous investigation of the responses they elicit.

Chondrogenic Differentiation Could Be Induced by Autologous Bone Marrow Mesenchymal Stem Cell-Derived Extracellular Matrix Scaffolds Without Exogenous Growth Factor

We previously found that the combination of an autologous bone mesenchymal stem cell-derived extracellular matrix (aBMSC-dECM) scaffold with bone marrow stimulation could enhance hyaline cartilage regeneration. We suspected that chondrogenic differentiation could be induced by the aBMSC-dECM scaffold. This study aimed to investigate whether aBMSC-dECM scaffolds could promote chondrogenic differentiation without exogenous growth factors. BMSCs were seeded on aBMSC-dECM scaffolds and cultured in vitro with or without transforming growth factor-β3 (E(+) or E(-) group). Atelocollagen scaffolds were used as controls (C(+) or C(-) group). The chondrogenic differentiation was evaluated by histological, biochemical, and real-time polymerase chain reaction assays. After 3 weeks, cartilage-like tissue with a homogeneous structure, a high cartilaginous matrix content (proteoglycan and type II collagen), and high expression levels of cartilage-associated genes (COL2A1, ACAN, and SOX9) were observed in the E(+), E(-), and C(+) groups. In addition, BMSCs in each scaffold (E group or C group) were preconditioned with chondrogenic media in vitro for 1 week, and then implanted in the backs of nude mice for 3 weeks. Three weeks later, cartilage matrix formation (proteoglycan and type II collagen) was achieved only in the E group, confirmed by safranin O staining and immunohistochemical staining for type II collagen. Taken together, these results indicate that aBMSC-dECM scaffolds could induce chondrogenic differentiation. Thus, they could be successful candidate scaffolds for cartilage tissue engineering.

Chondrogenic regeneration using bone marrow clots and a porous polycaprolactone-hydroxyapatite scaffold by three-dimensional printing

Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies.

MR elastography for evaluating regeneration of tissue-engineered cartilage in an ectopic mouse model

PURPOSE

The purpose of the present study was to apply noninvasive methods for monitoring regeneration and mechanical properties of tissue-engineered cartilage in vivo at different growth stages using MR elastography (MRE).

METHODS

Three types of scaffolds, including silk, collagen, and gelatin seeded by human mesenchymal stem cells, were implanted subcutaneously in mice and imaged at 9.4T where the shear stiffness and transverse MR relaxation time (T2 ) were measured for the regenerating constructs for 8 wk. An MRE phase contrast spin echo-based sequence was used for collecting MRE images. At the conclusion of the in vivo study, constructs were excised and transcript levels of cartilage-specific genes were quantitated using reverse-transcription polymerase chain reaction.

RESULTS

Tissue-engineered constructs showed a cartilage-like construct with progressive tissue formation characterized by increase in shear stiffness and decrease in T2 that can be correlated with increased cartilage transcript levels including aggrecan, type II collagen, and cartilage oligomeric matrix protein after 8 wk of in vivo culture.

CONCLUSION

Altogether, the outcome of this research demonstrates the feasibility of MRE and MRI for noninvasive monitoring of engineered cartilage construct's growth after implantation and provides noninvasive biomarkers for regeneration, which may be translated into treatment of tissue defects.

An autologous bone marrow mesenchymal stem cell-derived extracellular matrix scaffold applied with bone marrow stimulation for cartilage repair

PURPOSE

It is well known that implanting a bioactive scaffold into a cartilage defect site can enhance cartilage repair after bone marrow stimulation (BMS). However, most of the current scaffolds are derived from xenogenous tissue and/or artificial polymers. The implantation of these scaffolds adds risks of pathogen transmission, undesirable inflammation, and other immunological reactions, as well as ethical issues in clinical practice. The current study was undertaken to evaluate the effectiveness of implanting autologous bone marrow mesenchymal stem cell-derived extracellular matrix (aBMSC-dECM) scaffolds after BMS for cartilage repair.

METHODS

Full osteochondral defects were performed on the trochlear groove of both knees in 24 rabbits. One group underwent BMS only in the right knee (the BMS group), and the other group was treated by implantation of the aBMSC-dECM scaffold after BMS in the left knee (the aBMSC-dECM scaffold group).

RESULTS

Better repair of cartilage defects was observed in the aBMSC-dECM scaffold group than in the BMS group according to gross observation, histological assessments, immunohistochemistry, and chemical assay. The glycosaminoglycan and DNA content, the distribution of proteoglycan, and the distribution and arrangement of type II and I collagen fibers in the repaired tissue in the aBMSC-dECM scaffold group at 12 weeks after surgery were similar to that surrounding normal hyaline cartilage.

CONCLUSIONS

Implanting aBMSC-dECM scaffolds can enhance the therapeutic effect of BMS on articular cartilage repair, and this combination treatment is a potential method for successful articular cartilage repair.

Artificial Organs 2013: a year in review

In this Editor's Review, articles published in 2013 are organized by category and briefly summarized. We aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, the International Society for Rotary Blood Pumps, the International Society for Pediatric Mechanical Cardiopulmonary Support, and the Vienna International Workshop on Functional Electrical Stimulation, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level". Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide so meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley Periodicals, for their expert attention and support in the production and marketing of Artificial Organs. We look forward to recording further advances in the coming years.