The effect of nanofibre-based polyethersulfone (PES) scaffold on the chondrogenesis of human induced pluripotent stem cells

Articular cartilage and osteochondral tissue engineering techniques: Recent advances and challenges

In spite of the considerable achievements in the field of regenerative medicine in the past several decades, osteochondral defect regeneration remains a challenging issue among diseases in the musculoskeletal system because of the spatial complexity of osteochondral units in composition, structure and functions. In order to repair the hierarchical tissue involving different layers of articular cartilage, cartilage-bone interface and subchondral bone, traditional clinical treatments including palliative and reparative methods have showed certain improvement in pain relief and defect filling. It is the development of tissue engineering that has provided more promising results in regenerating neo-tissues with comparable compositional, structural and functional characteristics to the native osteochondral tissues. Here in this review, some basic knowledge of the osteochondral units including the anatomical structure and composition, the defect classification and clinical treatments will be first introduced. Then we will highlight the recent progress in osteochondral tissue engineering from perspectives of scaffold design, cell encapsulation and signaling factor incorporation including bioreactor application. Clinical products for osteochondral defect repair will be analyzed and summarized later. Moreover, we will discuss the current obstacles and future directions to regenerate the damaged osteochondral tissues.

Extracellular Vesicles in chondrogenesis and Cartilage regeneration

Extracellular vesicles (EVs), mainly exosomes and microvesicles, are bilayer lipids containing biologically active information, including nucleic acids and proteins. They are involved in cell communication and signalling, mediating many biological functions including cell growth, migration and proliferation. Recently, EVs have received great attention in the field of tissue engineering and regenerative medicine. Many in vivo and in vitro studies have attempted to evaluate the chondrogenesis potential of these microstructures and their roles in cartilage regeneration. EVs derived from mesenchymal stem cells (MSCs) or chondrocytes have been found to induce chondrocyte proliferation and chondrogenic differentiation of stem cells in vitro. Preclinical studies have shown that exosomes derived from MSCs have promising results in cartilage repair and in cell‐free therapy of osteoarthritis. This review will focus on the in vitro and in vivo chondrogenesis and cartilage regeneration of EVs as well as their potential in the treatment of osteoarthritis.

Chondrogenesis of human amniotic fluid stem cells in Chitosan-Xanthan scaffold for cartilage tissue engineering

Articular chondral lesions, caused either by trauma or chronic cartilage diseases such as osteoarthritis, present very low ability to self-regenerate. Thus, their current management is basically symptomatic, progressing very often to invasive procedures or even arthroplasties. The use of amniotic fluid stem cells (AFSCs), due to their multipotentiality and plasticity, associated with scaffolds, is a promising alternative for the reconstruction of articular cartilage. Therefore, this study aimed to investigate the chondrogenic potential of AFSCs in a micromass system (high-density cell culture) under insulin-like growth factor 1 (IGF-1) stimuli, as well as to look at their potential to differentiate directly when cultured in a porous chitosan-xanthan (CX) scaffold. The experiments were performed with a CD117 positive cell population, with expression of markers (CD117, SSEA-4, Oct-4 and NANOG), selected from AFSCs, after immunomagnetic separation. The cells were cultured in both a micromass system and directly in the scaffold, in the presence of IGF-1. Differentiation to chondrocytes was confirmed by histology and by using immunohistochemistry. The construct cell-scaffold was also analyzed by scanning electron microscopy (SEM). The results demonstrated the chondrogenic potential of AFSCs cultivated directly in CX scaffolds and also in the micromass system. Such findings support and stimulate future studies using these constructs in osteoarthritic animal models.

Review of Synthetic and Hybrid Scaffolds in Cartilage Tissue Engineering

Cartilage tissue is under extensive investigation in tissue engineering and regenerative medicine studies because of its limited regenerative potential. Currently, many scaffolds are undergoing scientific and clinical research. A key for appropriate scaffolding is the assurance of a temporary cellular environment that allows the cells to function as in native tissue. These scaffolds should meet the relevant requirements, including appropriate architecture and physicochemical and biological properties. This is necessary for proper cell growth, which is associated with the adequate regeneration of cartilage. This paper presents a review of the development of scaffolds from synthetic polymers and hybrid materials employed for the engineering of cartilage tissue and regenerative medicine. Initially, general information on articular cartilage and an overview of the clinical strategies for the treatment of cartilage defects are presented. Then, the requirements for scaffolds in regenerative medicine, materials intended for membranes, and methods for obtaining them are briefly described. We also describe the hybrid materials that combine the advantages of both synthetic and natural polymers, which provide better properties for the scaffold. The last part of the article is focused on scaffolds in cartilage tissue engineering that have been confirmed by undergoing preclinical and clinical tests.

Comparative impact of platelet rich plasma and transforming growth factor-β on chondrogenic differentiation of human adipose derived stem cells

Introduction: Transforming growth factor-beta (TGF-β) is known as standard chondrogenic differentiation agent, even though it comes with undesirable side effects such as early hypertrophic maturation, mineralization, and secretion of inflammatory/angiogenic factors. On the other hand, platelet-rich plasma (PRP) is found to have a chondrogenic impact on mesenchymal stem cell proliferation and differentiation, with no considerable side effects. Therefore, we compared chondrogenic impact of TGF-β and PRP on adipose-derived stem cells (ADSCs), to see if PRP could be introduced as an alternative to TGF-β.

Methods: Differentiation of ADSCs was monitored using a couple of methods including glycosaminoglycan production, miRNAs expression, vascular endothelial growth factor (VEGF)/tumor necrosis factor alpha (TNFα) secretion, alkaline phosphatase (ALP) and calcium content assays.

Results: Accordingly, the treatment of differentiating cells with 5% (v/v) PRP resulted in higher glycosaminoglycan production, enhanced SOX9 transcription, and lowered TNFα and VEGF secretion compared to the control and TGF-β groups. Besides, the application of PRP to the media up-regulated miR-146a and miR-199a in early and late stages of chondrogenesis, respectively.

Conclusion: PRP induces in vitro chondrogenesis, as well as TGF-β with lesser inflammatory and hypertrophic side effects.

Impact of Induced Pluripotent Stem Cells in Bone Repair and Regeneration

PURPOSE OF REVIEW

The main objective of this article is to investigate the current trends in the use of induced pluripotent stem cells (iPSCs) for bone tissue repair and regeneration.

RECENT FINDINGS

Pluripotent stem cell-based tissue engineering has extended innovative therapeutic approaches for regenerative medicine. iPSCs have shown osteogenic differentiation capabilities and would be an innovative resource of stem cells for bone tissue regenerative applications. This review recapitulates the current knowledge and recent progress regarding utilization of iPSCs for bone therapy. A review of current findings suggests that a combination of a three-dimensional scaffolding system with iPSC technology to mimic the physiological complexity of the native stem cell niche is highly favorable for bone tissue repair and regeneration.

Improved chondrogenic response of mesenchymal stem cells to a polyethersulfone/polyaniline blended nanofibrous scaffold

Owing to the fact that the cartilage tissue is not able to repair itself, the treatment of the joint damages is very difficult by current methods. Induction of tissue repair requires suitable cell and extracellular matrix. Providing these two parts can only be done using tissue engineering. In the present study, polyethersulfone (PES) and polyaniline (PANI) blend was electrospined for nanofibrous scaffold fabrication. Mesenchymal stem cells were isolated from human adipose tissue (AT-MSCs), and after characterization cultured on the PES-PANI scaffold and culture plate. Electron microscopic and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assays were used for biocompatibility evaluation of the scaffold and the chondrogenic differentiation potential of AT-MSCs were investigated by staining of proteoglycans and gene and protein expression evaluation. Alcian blue staining, real-time reverse-transcriptase polymerase chain reaction and Western blot results showed that chondrogenic differentiation potential of AT-MSCs was significantly increased when grown on PES-PANI nanofibers and was compared to the one grown on a culture plate. According to the results, PES-PANI has a promising potential to be used as a biomedical implant in patients with joints lesion, such as arthritis and osteoarthritis.

Biomaterials and Gene Manipulation in Stem Cell-Based Therapies for Spinal Cord Injury

Spinal cord injury (SCI), a prominent health issue, represents a substantial portion of the global health care burden. Stem cell-based therapies provide novel solutions for SCI treatment, yet obstacles remain in the form of low survival rate, uncontrolled differentiation, and functional recovery. The application of engineered biomaterials in stem cell therapy provides a physicochemical microenvironment that mimics the stem cell niche, facilitating self-renewal, stem cell differentiation, and tissue reorganization. Nonetheless, external microenvironment support is inadequate, and some obstacles persist, for example, limited sources, gradual aging, and immunogenicity of stem cells. Targeted stem cell gene manipulation could eliminate many of these drawbacks, allowing safer, more effective use under regulation of intrinsic mechanisms. Additionally, through genetic labeling of stem cells, their role in tissue engineering may be elucidated. Therefore, combining stem cell therapy, materials science, and genetic modification technologies may shed light on SCI treatment. Herein, recent advances and advantages of biomaterials and gene manipulation, especially with respect to stem cell-based therapies, are highlighted, and their joint performance in SCI is evaluated. Current technological limitations and perspectives on future directions are then discussed. Although this combination is still in the early stages of development, it is highly likely to substantially contribute to stem cell-based therapies in the foreseeable future.