Stem Cells For Cartilage Regeneration Research Articles

Dynamic Proteinaceous Hydrogel Enables In‐Situ Recruitment of Endogenous TGF‐β1 and Stem Cells for Cartilage Regeneration

AbstractArticular cartilage is a tissue with relatively poor self‐regeneration capacity due to insufficient blood vessels and chondrocytes in the region. Biomaterial‐assisted tissue engineering has shown great potential in cartilage regeneration. However, there are still many worries over the uses of exogenous growth factors, stem cells and scaffolds. To address these concerns, here a dynamic proteinaceous hydrogel with a self‐recruiting ability of cartilage‐inducing factor for in situ cartilage regeneration is reported. The dynamic hydrogel (Pep‐GelSH) is prepared by using thiol‐modified gelatin and thiol‐capped TGF‐β1‐affinity peptide through the Au‐S coordination. The injectability and self‐recovery of Pep‐GelSH hydrogel enabled not only minimally invasive implantation but also the adaptability of the scaffold to irregular defect shapes. Meanwhile, the dynamic hydrogel showed improved adherence to the host tissue and allowed quick infiltration of host cells. More importantly, the hydrogel significantly enhanced local enrichment of endogenous TGF‐β1 and led to the recruitment of stem cells in vivo. After implantation, the hydrogel scaffold triggered the innate repair capacity of cartilage defects by successively promoting stem cells recruitment, infiltration and differentiation, resulting in significantly enhanced chondrogenesis and improved cartilage repair. Therefore, the study in this work may provide a feasible and promising approach for in situ cartilage regeneration.

Adult Stem Cells for Cartilage Regeneration.

As cartilage is an avascular, aneural structure, it has very low capabilities of self-repair. Osteoarthritis prevalence is increasing, and there are no clinically approved management techniques that can cure the degradation of cartilage. This report investigates the efficacy of different sources of cells to generate articular cartilage. Autologous chondrocyte implantation has been used to some extent in clinics; however it has not generated efficient, reliable results, and there is no evidence of long-term success. The usage of stem cells is more promising, particularly mesenchymal stem cells (MSCs). Human embryonic stem cells (hESCs) have also been trialed; however, it is important to note that the process of differentiation into chondrocytes is not fully understood, and the cartilage produced can often be of poor quality. MSCs seems to be the way forward, and hESCs will perhaps need further study with the usage of MSC differentiation methodology.

Mapping Thematic Trends and Analysing Hotspots Concerning the Use of Stem Cells for Cartilage Regeneration: A Bibliometric Analysis From 2010 to 2020.

Background: Defects of articular cartilage represent a common condition that usually progresses to osteoarthritis with pain and dysfunction of the joint. Current treatment strategies have yielded limited success in these patients. Stem cells are emerging as a promising option for cartilage regeneration. We aim to summarize the developmental history of stem cells for cartilage regeneration and to analyse the relevant trends and hotspots. Methods: We screened all relevant literature on stem cells for cartilage regeneration from Web of Science during 2010–2020 and analysed the research trends in this field by VOSviewer and CiteSpace. We also summarized previous clinical trials. Results: We screened 1,011 publications. China contributed the largest number of publications (317, 31.36%) and citations (81,376, 48.61%). The United States achieved the highest H-index (39). Shanghai Jiao Tong University had the largest number of publications (34) among all full-time institutions. The Journal of Biomaterials and Stem Cell Research and Therapy published the largest number of studies on stem cells for cartilage regeneration (35). SEKIYA I and YANG F published the majority of articles in this field (14), while TOH WS was cited most frequently (740). Regarding clinical research on stem cells for cartilage regeneration, the keyword “double-blind” emerged in recent years, with an average year of 2018.75. In tissue engineering, the keyword “3D printing” appeared latest, with an average year of 2019.625. In biological studies, the key word “extracellular vesicles” appeared latest, with an average year of 2018.9091. The current research trend indicates that basic research is gradually transforming to tissue engineering. Clinical trials have confirmed the safety and feasibility of stem cells for cartilage regeneration. Conclusion: Multiple scientific methods were employed to reveal productivity, collaborations, and research hotspots related to the use of stem cells for cartilage regeneration. 3D printing, extracellular vesicles, and double-blind clinical trials are research hotspots and are likely to be promising in the near future. Further studies are needed for to improve our understanding of this field, and clinical trials with larger sample sizes and longer follow-up periods are needed for clinical transformation.

Chitosan hydrogel/3D-printed poly(ε‐caprolactone) hybrid scaffold containing synovial mesenchymal stem cells for cartilage regeneration based on tetrahedral framework nucleic acid recruitment

Articular cartilage (AC) injury repair has always been a difficult problem for clinicians and researchers. Recently, a promising therapy based on mesenchymal stem cells (MSCs) has been developed for the regeneration of cartilage defects. As endogenous articular stem cells, synovial MSCs (SMSCs) possess strong chondrogenic differentiation ability and articular specificity. In this study, a cartilage regenerative system was developed based on a chitosan (CS) hydrogel/3D-printed poly(ε‐caprolactone) (PCL) hybrid containing SMSCs and recruiting tetrahedral framework nucleic acid (TFNA) injected into the articular cavity. TFNA, which is a promising DNA nanomaterial for improving the regenerative microenvironment, could be taken up into SMSCs and promoted the proliferation and chondrogenic differentiation of SMSCs. CS, as a cationic polysaccharide, can bind to DNA through electrostatic action and recruit free TFNA after articular cavity injection in vivo. The 3D-printed PCL scaffold provided basic mechanical support, and TFNA provided a good microenvironment for the proliferation and chondrogenic differentiation of the delivered SMSCs and promoted cartilage regeneration, thus greatly improving the repair of cartilage defects. In conclusion, this study confirmed that a CS hydrogel/3D-printed PCL hybrid scaffold containing SMSCs could be a promising strategy for cartilage regeneration based on chitosan-directed TFNA recruitment and TFNA-enhanced cell proliferation and chondrogenesis.

Zone-Dependent Architecture and Biochemical Composition of Decellularized Porcine Nasal Cartilage Modulate the Activity of Adipose Tissue-Derived Stem Cells in Cartilage Regeneration.

Previous anatomical studies have shown different functional zones in human nasal septal cartilage (NC). These zones differ in respect to histological architecture and biochemical composition. The aim of this study was to investigate the influence of these zones on the fate of stem cells from a regenerative perspective. Therefore, decellularized porcine septal cartilage was prepared and subjected to histological assessment to demonstrate its equivalence to human cartilage. Decellularized porcine NC (DPNC) exposed distinct surfaces depending on two different histological zones: the outer surface (OS), which is equivalent to the superficial zone, and the inner surface (IS), which is equivalent to the central zone. Human adipose tissue-derived stem cells (ASCs) were isolated from the abdominal fat tissue of five female patients and were seeded on the IS and OS of DPNC, respectively. Cell seeding efficiency (CSE), vitality, proliferation, migration, the production of sulfated glycosaminoglycans (sGAG) and chondrogenic differentiation capacity were evaluated by histological staining (DAPI, Phalloidin, Live-Dead), biochemical assays (alamarBlue®, PicoGreen®, DMMB) and the quantification of gene expression (qPCR). Results show that cell vitality and CSE were not influenced by DPNC zones. ASCs, however, showed a significantly higher proliferation and elevated expression of early chondrogenic differentiation, as well as fibrocartilage markers, on the OS. On the contrary, there was a significantly higher upregulation of hypertrophy marker MMP13 (p < 0.0001) and GAG production (p = 0.0105) on the IS, whereas cell invasion into the three-dimensional DPNC was higher in comparison to the OS. We conclude that the zonal-dependent distinct architecture and composition of NC modulates activities of ASCs seeded on DPNC. These findings might be used for engineering of cartilage substitutes needed in facial reconstructive surgery that yield an equivalent histological and functional structure, such as native NC.

A chondroitin sulfate based injectable hydrogel for delivery of stem cells in cartilage regeneration.

Chondroitin sulfate (CS), as a popular material for cartilage tissue engineering scaffolds, has been extensively studied and reported for its safety and excellent biocompatibility. However, the rapid degradation of pure CS scaffolds has brought a challenge to regenerate neo-tissue similar to natural articular cartilage effectively. Meanwhile, the poly(ethene glycol) (PEG) -based biopolymer is frequently applied as a structural constituent material because of its remarkable mechanical properties, long-lasting in vivo stability, and hypo-immunity. Here, we report that the combination of CS and hyperbranched multifunctional PEG copolymer (HB-PEG) could synergistically promote cartilage repair. The thiol functionalised CS (CS-SH)/HB-PEG hydrogel scaffolds were fabricated via thiol-ene reaction, which exhibits rapid gelation, excellent mechanical properties and prolonged degradation properties. We found that rat adipose-derived mesenchymal stem cells presented great cell viability and improved chondrogenesis in CS-SH/HB-PEG hydrogels. Moreover, the injectable hydrogel scaffolds reduced stem cell inflammatory response, consistent with the well-documented anti-inflammatory activities of CS.

Fibrous Scaffolds Enhanced the Paracrine Signaling of Mesenchymal Stem Cells for Cartilage Regeneration

Secretome profiles of mesenchymal stem cells (MSCs) are reflective of their local microenvironments and exert an impact on the surrounding cells, eliciting regenerative responses that creates an opportunity for exploiting MSCs towards a cell-free therapy for cartilage repair. The conventional method of culturing MSCs on a tissue culture plate does not provide the physiological microenvironment for optimum secretome production. This study explored the potential of fibrous scaffolds with specific surface topographies in influencing the MSC secretome production and in enhancing the functionality of MSCs and chondrocytes for cartilage repair. Conditioned media generated from MSCs cultured on fibrous scaffolds improved secretome yield and profile that promoted migration, proliferation, chondrogenesis, as well as mitigated inflammation and protected chondrocytes from apoptosis. FAK and ERK signaling were identified as the mechanotransduction pathways to modulate the MSC morphology and its secretome production, which highlighted scaffold fiber orientation as a key design parameter to direct cellular behavior of MSCs and enhance its paracrine functions. This study demonstrates that a fibrous culture platform could be a more efficient approach for improving and fine-tuning the repertoire of MSC secretome for articular cartilage regeneration.

Culture Time Needed to Scale up Infrapatellar Fat Pad Derived Stem Cells for Cartilage Regeneration: A Systematic Review.

Adipose tissue is a rich source of stem cells, which are reported to represent 2% of the stromal vascular fraction (SVF). The infrapatellar fat pad (IFP) is a unique source of tissue, from which human adipose-derived stem cells (hADSCs) have been shown to harbour high chondrogenic potential. This review aims to calculate, based on the literature, the culture time needed before an average knee articular cartilage defect can be treated using stem cells obtained from arthroscopically or openly harvested IFP. Firstly, a systematic literature review was performed to search for studies that included the number of stem cells isolated from the IFP. Subsequent analysis was conducted to identify the amount of IFP tissue harvestable, stem cell count and the overall yield based on the harvesting method. We then determined the minimum time required before treating an average-sized knee articular cartilage defect with IFP-derived hADSCs by using our newly devised equation. The amount of fat tissue, the SVF cell count and the stem cell yield are all lower in arthroscopically harvested IFP tissue compared to that collected using arthrotomy. As an extrapolation, we show that an average knee defect can be treated in 20 or 17 days using arthroscopically or openly harvested IFP-derived hADSCs, respectively. In summary, the systematic review conducted in this study reveals that there is a higher amount of fat tissue, SVF cell count and overall yield (cells/volume or cells/gram) associated with open (arthrotomy) compared to arthroscopic IFP harvest. In addition to these review findings, we demonstrate that our novel framework can give an indication about the culture time needed to scale up IFP-derived stem cells for the treatment of articular cartilage defects based on harvesting method.

Clinical application of mesenchymal stem cells for cartilage regeneration

Clinical application of mesenchymal stem cells for cartilage regeneration

Infrapatellar Fat Pad Stem Cells Responsiveness to Microenvironment in Osteoarthritis: From Morphology to Function.

Recently, infrapatellar fat pad (IFP) has been considered as a source of stem cells for cartilage regeneration in osteoarthritis (OA) due to their ability for differentiation into chondrocytes. However, stressful conditions, like that related to OA, may induce a pathogenic reprograming. The aim of this study was to characterize the structural and functional properties of a new population of stem cells isolated from osteoarthritic infrapatellar fat pad (OA-IFP). Nine OA patients undergoing total knee arthroplasty (TKA) were enrolled in this study [median age = 74 years, interquartile range (IQR) = 78.25-67.7; median body mass index = 29.4 Kg/m2, IQR = 31.7-27.4]. OA-IFP stem cells were isolated and characterized for morphology, stemness, metabolic profile and multi-differentiative potential by transmission electron microscopy, flow cytometric analysis, gene expression study and cytochemistry. OA-IFP stem cells displayed a spindle-like morphology, self-renewal potential and responsiveness (CD44, CD105, VEGFR2, FGFR2, IL1R, and IL6R) to microenvironmental stimuli. Characterized by high grade of stemness (STAT3, NOTCH1, c-Myc, OCT-4, KLF4, and NANOG), the cells showed peculiar immunophenotypic properties (CD73+/CD39+/CD90+/CD105+/CD44–/+/CD45–). The expression of HLA-DR, CD34, Fas and FasL was indicative of a possible phenotypic reprograming induced by inflammation. Moreover, the response to mechanical stimuli together with high expression level of COL1A1 gene, suggested their possible protective response against in vivo mechanical overloading. Conversely, the low expression of CD38/NADase was indicative of their inability to counteract NAD+-mediated OA inflammation. Based on the ultrastructural, immunophenotypic and functional characterization, OA-IFP stem cells were hypothesized to be primed by the pathological environment and to exert incomplete protective activity from OA inflammation.

Application of Cord Blood and Cord Blood-Derived Induced Pluripotent Stem Cells for Cartilage Regeneration

Regeneration of articular cartilage is of great interest in cartilage tissue engineering since articular cartilage has a low regenerative capacity. Due to the difficulty in obtaining healthy cartilage for transplantation, there is a need to develop an alternative and effective regeneration therapy to treat degenerative or damaged joint diseases. Stem cells including various adult stem cells and pluripotent stem cells are now actively used in tissue engineering. Here, we provide an overview of the current status of cord blood cells and induced pluripotent stem cells derived from these cells in cartilage regeneration. The abilities of these cells to undergo chondrogenic differentiation are also described. Finally, the technical challenges of articular cartilage regeneration and future directions are discussed.

Shelf Life Evaluation of Clinical Grade Chondrogenic Induced Aged Adult Stem Cells for Cartilage Regeneration

The study objectives include, enhancing the proliferations of aged bone marrow stem cells (BMSCs) and adipose stem cells (ADSCs); and evaluating the shelf lives of clinical grade chondrogenically induced cells from both samples. ADSCs and BMSCs from 56 patients (76 ± 8 yrs) were proliferated using basal medium (FD) and at (5, 10, 15, 20 and 25) ng/ml of basal fibroblast growth factor (bFGF). They were induced to chondrogenic lineage and stored for more than 120 hrs in FD, serum, Dulbecco’s phosphate buffered saline (DPBS) and saline at 4 °C. In FD, cells stagnated and BMSCs’ population doubling time (PDT) was 137 ± 30 hrs, while ADSCs’ was 129.7 ± 40 hrs. bFGF caused PDT’s decrease to 24.5 ± 5.8 hrs in BMSCs and 22.0 ± 6.5 hrs in ADSCs (p = 0.0001). Both cells were positive to stem cell markers before inductions and thereafter, expressed significantly high chondrogenic genes (p = 0.0001). On shelf life, both cells maintained viabilities and counts above 70% in FD and serum after 120 hrs. BMSCs’ viabilities in DPBS fell below 70% after 96 hrs and saline after 72 hrs. ADSCs’ viability fell below 70% in DPBS after 24 hrs and saline within 24 hrs. Concentrations between 20 ng/ml bFGF is ideal for aged adult cells’ proliferation and delivery time of induced BMSCs and ADSCs can be 120 hrs in 4 °C serum.

The Potency of Induced Pluripotent Stem Cells in Cartilage Regeneration and Osteoarthritis Treatment.

Osteoarthritis (OA) is the most common chronic disabling condition effecting the elderly, significantly impacting an individual patient's quality of life. Current treatment options for OA are focused on pain management and slowing degradation of cartilage. Some modern surgical techniques aimed at encouraging regeneration at defect sites have met with limited long-term success. Mesenchymal stem cells (MSCs) have been viewed recently as a potential tool in OA repair due to their chondrogenic capacity. Several studies have shown success with regards to reducing patient's OA-related pain and discomfort but have been less successful in inducing chondrocyte regeneration. The heterogeneity of MSCs and their limited proliferation capacity also raises issues when developing an off-the-shelf treatment for OA. Induced pluripotent stem cell (iPSC) technology, which allows for the easy production of cells capable of prolonged self-renewal and producing any somatic cell type, may overcome those limitations. Patient derived iPSCs can also be used to gain new insight into heredity-related OA. Efforts to generate chondrocytes from iPSCs through embryoid bodies or mesenchymal intermediate stages have struggled to produce with optimal functional characteristics. However, iPSCs potential to produce cells for future OA therapies has been supported by iPSC-derived teratomas, which have shown an ability to produce functional, stable articular cartilage. Other iPSCs-chondrogenic protocols are also improving by incorporating tissue engineering techniques to better mimic developmental conditions.

Advances and Prospects in Stem Cells for Cartilage Regeneration.

The histological features of cartilage call attention to the fact that cartilage has a little capacity to repair itself owing to the lack of a blood supply, nerves, or lymphangion. Stem cells have emerged as a promising option in the field of cartilage tissue engineering and regenerative medicine and could lead to cartilage repair. Much research has examined cartilage regeneration utilizing stem cells. However, both the potential and the limitations of this procedure remain controversial. This review presents a summary of emerging trends with regard to using stem cells in cartilage tissue engineering and regenerative medicine. In particular, it focuses on the characterization of cartilage stem cells, the chondrogenic differentiation of stem cells, and the various strategies and approaches involving stem cells that have been used in cartilage repair and clinical studies. Based on the research into chondrocyte and stem cell technologies, this review discusses the damage and repair of cartilage and the clinical application of stem cells, with a view to increasing our systematic understanding of the application of stem cells in cartilage regeneration; additionally, several advanced strategies for cartilage repair are discussed.

Adipose-derived stem cells in cartilage regeneration: current perspectives.

Repair of cartilage injuries represents a musculoskeletal medicine criticism because of the poor ability to self-renewal of adult cartilage. Therefore, research focuses on developing new regenerative strategies combining chondrocytes or stem cells, scaffolds and growth factors. Because of the low proliferation capability of explanted chondrocytes, new chondrogenesis models, employing human adipose-derived stem cells (ASCs), have been investigated. ASCs are readily accessible with no morbidity and display the capability to differentiate into several cell lineages, including the spontaneous chondrogenic differentiation when entrapped in collagen gel scaffolds. Recent studies also defined some biomolecular mechanisms involved in ASC chondrogenesis in vitro, and their regenerative properties in bioengineered scaffolds and in the presence of growth factors. However, further investigations are required to validate these exciting preclinical results for the application of bioenginereed ASCs in the clinical practice.

High capacity of purified mesenchymal stem cells for cartilage regeneration

High capacity of purified mesenchymal stem cells for cartilage regeneration

Characterization of adipose tissue-derived stromal vascular fraction for clinical application to cartilage regeneration.

Bone marrow concentration (BMC) is the most recognized procedure to prepare mesenchymal stem cells for cartilage regeneration. However, bone marrow aspiration is highly invasive and results in low stem cell numbers. Recently, adipose tissue-derived stromal vascular fraction (AT-SVF) was studied as an alternate source of stem cells for cartilage regeneration. However, AT-SVF is not fully characterized in terms of functional equivalence to BMC. Therefore, in this study, we characterized AT-SVF and assessed its suitability as a one-step surgical procedure for cartilage regeneration, as an alternative to BMC. AT-SVF contained approximately sixfold less nucleated cells than BMC. However, adherent cells in AT-SVF were fourfold greater than BMC. Additionally, the colony-forming unit frequency of AT-SVF was higher than that of BMC, at 0.5 and 0.01%, respectively. The mesenchymal stem cell (MSC) population (CD45-CD31-CD90+CD105+) was 4.28% in AT-SVF and 0.42% in BMC, and the adipose-derived stromal cell (ASC) population (CD34+CD31-CD146-) was 32% in AT-SVF and 0.16% in BMC. In vitro chondrogenesis demonstrated that micromass was not formed in BMC, whereas it was clearly formed in AT-SVF. Taken together, uncultured AT-SVF could be used in one-step surgery for cartilage regeneration as a substitute for BMC.

Adipose-derived stem cells for cartilage regeneration - moving towards clinical applicability

Despite multiple methods of treatment and a wealth of research in the field of regenerative medicine focusing on cartilage defects, the management of cartilage injuries remains a challenge. A recent study by Van Pham and colleagues proposes a method for preconditioning autologous adipose-derived stem cells. Their study offers evidence about the increased proliferative and chondrogenetic capabilities of platelet-rich plasma-treated adipose-derived stem cells and the increased efficiency of these in treating articular cartilage defects in mice. Even though the method needs further elaboration and the composition of the repair tissue requires investigation, the results are promising for the design of clinically acceptable cell therapies aimed at cartilage regeneration.

The clinical benefit of stem cells in cartilage regeneration

The results of a recent randomized, controlled study suggest than intra-articular injection of autologous stem cells collected from peripheral blood might improve the outcome of surgical approaches to regeneration of articular cartilage after injury. However, questions remain regarding the clinical benefit and feasibility of such an approach.

Repair of Large Animal Partial-Thickness Cartilage Defects Through Intraarticular Injection of Matrix-Rejuvenated Synovium-Derived Stem Cells

Cartilage defects have a limited ability to self-heal. Stem cell treatment is a promising approach; however, replicative senescence is a challenge to acquiring large-quantity and high-quality stem cells for cartilage regeneration. Synovium-derived stem cells (SDSCs) are a tissue-specific stem cell for cartilage regeneration. Our recent findings suggest that decellularized stem cell matrix (DSCM) can rejuvenate expanded SDSCs in cell proliferation and chondrogenic potential. In this study, we were investigating (1) whether transforming growth factor (TGF)-β1 and TGF-β3 played a similar role in chondrogenic induction of SDSCs after expansion on either DSCM or plastic flasks (plastic), and (2) whether DSCM-expanded SDSCs had an enhanced capacity in repairing partial-thickness cartilage defects in a minipig model. SDSCs were isolated from synovium in two 3-month-old pigs and DSCM was prepared using SDSCs. Passage 2 SDSCs were expanded on either DSCM or plastic for one passage. The expanded cells were evaluated for cell morphology, chondrogenic capacity, and related mechanisms. TGF-β1 and TGF-β3 were compared for their role in chondrogenesis of SDSCs after expansion on either DSCM or plastic. The chondrogenic induction medium without TGF-β served as a control. In 13 minipigs, we intraarticularly injected DSCM- or plastic-expanded SDSCs or saline into knee partial-thickness cartilage defects and assessed their repair using histology and immunohistochemistry. We found DSCM-expanded SDSCs were small, had a fibroblast-like shape, and grew quickly in a three-dimensional format with concomitant up-regulation of phosphocyclin D1 and TGF-β receptor II. Plastic-expanded SDSCs exhibited higher mRNA levels of chondrogenic markers when incubated with TGF-β3, while DSCM-expanded SDSCs displayed comparable chondrogenic potential when treated with either TGF-β isotype. In the minipig model, DSCM-expanded SDSCs were better than plastic-expanded SDSCs in enhancing collagen II and sulfated glycosaminoglycan expression in repair of partial-thickness cartilage defects, but both groups were superior to the saline control group. Our observations suggested that DSCM is a promising cell expansion system that can promote cell proliferation and enhance expanded cell chondrogenic potential in vitro and in vivo. Our approach could lead to a tissue-specific cell expansion system providing large-quantity and high-quality stem cells for the treatment of cartilage defects.