Induction of bone marrow mesenchymal stem cell chondrogenesis following short-term suspension culture

The clinical efficacy of arthroscopic therapy with knee infrapatellar fat pad cell concentrates in treating knee cartilage lesion: a prospective, randomized, and controlled study

Introduction

To evaluate the clinical efficacy of arthroscopic therapy with infrapatellar fat pad cell concentrates in treating knee cartilage lesions, we conducted a prospective randomized single-blind clinical study of controlled method.

Methods

Sixty cases from Shanghai Changzheng Hospital from April 2018 to December 2019 were chosen and randomly divided into 2 groups equally. Patients in the experiment group were treated through knee arthroscopy with knee infrapatellar fat pad cell concentrates containing mesenchymal stromal cells, while patients in the control group were treated through regular knee arthroscopic therapy. VAS and WOMAC scores were assessed at pre-operation, and 6 weeks, 12 weeks, 6 months, and 12 months after intervention. MORCART scores were assessed at pre-operation and 12 months after intervention.

Results

Twenty-nine cases in the experiment group and 28 cases in the control group were followed up. No significant difference in VAS, WOMAC, and MOCART scores were found between the two groups before surgery (P > 0.05). The WOMAC total and WOMAC function scores of the experiment group were significantly lower than those of the control group 6 months and 12 months after surgery (P < 0.05). The VAS rest and VAS motion scores of the experiment group were found significantly lower than those of the control group 12 months after surgery (P < 0.05). The MOCART scores of the experiment group were found significantly higher compared with the control group 12 months after surgery (P < 0.05). No significant difference in WOMAC stiffness scores were found between the two groups.

Conclusions

The short-term results of our study are encouraging and demonstrate that knee arthroscopy with infrapatellar fat pad cell concentrates containing mesenchymal stromal cells is safe and provides assistance in reducing pain and improving function in patients with knee cartilage lesions.

Trial registration

ChiCTR1800015379. Registered on 27 March 2018, http://www.chictr.org.cn/showproj.aspx?proj=25901.

Culture Conditions that Support Expansion and Chondrogenesis of Middle-Aged Rat Mesenchymal Stem Cells

OBJECTIVE

Rats are an early preclinical model for cartilage tissue engineering, and a practical species for investigating the effects of aging. However, rats may be a poor aging model for mesenchymal stem cells (MSCs) based on laboratory reports of a severe decline in chondrogenesis beyond young adulthood. Such testing has not been conducted with MSCs seeded in a scaffold, which can improve the propensity of MSCs to undergo chondrogenesis. Therefore, the objective of this study was to evaluate chondrogenesis of middle-aged rat MSCs encapsulated in agarose.

DESIGN

MSCs from 14- to 15-month-old rats were expanded, seeded into agarose, and cultured in chondrogenic medium with or without 5% serum for 15 days. Samples were evaluated for cell viability and cartilaginous extracellular matrix (ECM) accumulation. Experiments were repeated using MSCs from 6-week-old rats.

RESULTS

During expansion, middle-aged rat MSCs demonstrated a diminishing proliferation rate that was improved ~2-fold in part by transient exposure to chondrogenic medium. In agarose culture in defined medium, middle-aged rat MSCs accumulated ECM to a much greater extent than negative controls. Serum supplementation improved cell survival ~2-fold, and increased ECM accumulation ~3-fold. Histological analysis indicated that defined medium supported chondrogenesis in a subset of cells, while serum-supplementation increased the frequency of chondrogenic cells. In contrast, young rat MSCs experienced robust chondrogenesis in defined medium that was not improved with serum-supplementation.

CONCLUSIONS

These data demonstrate a previously-unreported propensity of middle-aged rat MSCs to undergo chondrogenesis, and the potential of serum to enhance chondrogenesis of aging MSCs.

Effect of culture duration on chondrogenic preconditioning of equine bone marrow mesenchymal stem cells in self-assembling peptide hydrogel

Ex vivo induction of chondrogenesis is a promising approach to improve upon the use of bone marrow mesenchymal stem cells (MSCs) for cartilage tissue engineering. This study evaluated the potential to induce chondrogenesis with days of culture in chondrogenic medium for MSCs encapsulated in self-assembling peptide hydrogel. To simulate the transition from preconditioning culture to implantation, MSCs were isolated from self-assembling peptide hydrogel into an individual cell suspension. Commitment to chondrogenesis was evaluated by seeding preconditioned MSCs into agarose and culturing in the absence of the chondrogenic cytokine transforming growth factor beta (TGFβ). Positive controls consisted of undifferentiated MSCs seeded into agarose and cultured in medium containing TGFβ. Three days of preconditioning was sufficient to produce chondrogenic MSCs that accumulated ∼75% more cartilaginous extracellular matrix than positive controls by day 17. However, gene expression of type X collagen was ∼65-fold higher than positive controls, which was attributed to the absence of TGFβ. Potential induction of immunogenicity with preconditioning culture was indicated by expression of major histocompatibility complex class II (MHCII), which was nearly absence in undifferentiated MSCs, and ∼7% positive for preconditioned cells. These data demonstrate the potential to generate chondrogenic MSCs with days of self-assembling peptide hydrogel, and the ability to readily recover an individual cell suspension that is suited for injectable therapies. However, continued exposure to TGFβ may be necessary to prevent hypertrophy indicated by type X collagen expression, while immunogenicity may be a concern for allogeneic applications. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1368-1375, 2019.

Differential Effects of the Antioxidants N-Acetylcysteine and Pyrrolidine Dithiocarbamate on Mesenchymal Stem Cell Chondrogenesis

Introduction

Mesenchymal stem cell (MSC) chondrogenesis is associated with increases in intracellular reactive oxygen species (ROS), which may result in oxidative stress that is detrimental to cartilage regeneration. This study evaluated the ability of the antioxidants N-acetylcysteine (NAC) or pyrrolidine dithiocarbamate (PDTC) to reduce intracellular ROS, and their effect on MSC chondrogenesis and maturation of cartilage-like extracellular matrix.

Methods

Equine bone marrow MSCs were cultured in serum-supplemented chondrogenic medium with or without NAC or PDTC. ROS was quantified in monolayer after 8 and 72 h of culture. MSCs were seeded into agarose, cultured for 15 days, and analyzed for viable cell density, glycosaminoglycan (GAG) and hydroxyproline accumulation, and collagen gene expression. PDTC cultures were evaluated for oxidative damage by protein carbonylation, and mechanical properties via compressive testing.

Results

NAC significantly lowered levels of ROS after 8 but not 72 h, and suppressed GAG accumulation (70%). In secondary experiments using serum-free medium, NAC significantly increased levels of ROS at 72 h, and lowered cell viability and extracellular matrix accumulation. PDTC significantly reduced levels of ROS (~ 30%) and protein carbonylation (27%), and enhanced GAG accumulation (20%). However, the compressive modulus for PDTC-treated samples was significantly lower (40%) than controls. Gene expression was largely unaffected by the antioxidants.

Conclusions

NAC demonstrated a limited ability to reduce intracellular ROS in chondrogenic culture, and generally suppressed accumulation of extracellular matrix. Conversely, PDTC was an effective antioxidant that enhanced GAG accumulation, although the concomitant reduction in compressive properties is a significant limitation for cartilage repair.

Tissue engineering potential of human dermis-isolated adult stem cells from multiple anatomical locations

Abundance and accessibility render skin-derived stem cells an attractive cell source for tissue engineering applications. Toward assessing their utility, the variability of constructs engineered from human dermis-isolated adult stem (hDIAS) cells was examined with respect to different anatomical locations (foreskin, breast, and abdominal skin), both in vitro and in a subcutaneous, athymic mouse model. All anatomical locations yielded hDIAS cells with multi-lineage differentiation potentials, though adipogenesis was not seen for foreskin-derived hDIAS cells. Using engineered cartilage as a model, tissue engineered constructs from hDIAS cells were compared. Construct morphology differed by location. The mechanical properties of human foreskin- and abdominal skin-derived constructs were similar at implantation, remaining comparable after 4 additional weeks of culture in vivo. Breast skin-derived constructs were not mechanically testable. For all groups, no signs of abnormality were observed in the host. Addition of aggregate redifferentiation culture prior to construct formation improved chondrogenic differentiation of foreskin-derived hDIAS cells, as evident by increases in glycosaminoglycan and collagen contents. More robust Alcian blue staining and homogeneous cell populations were also observed compared to controls. Human DIAS cells elicited no adverse host responses, reacted positively to chondrogenic regimens, and possessed multi-lineage differentiation potential with the caveat that efficacy may differ by anatomical origin of the skin. Taken together, these results suggest that hDIAS cells hold promise as a potential cell source for a number of tissue engineering applications.

Advances in regenerative orthopedics

Orthopedic injuries are common and a source of much misery and economic stress. Several relevant tissues, such as cartilage, meniscus, and intra-articular ligaments, do not heal. And even bone, which normally regenerates spontaneously, can fail to mend. The regeneration of orthopedic tissues requires 4 key components: cells, morphogenetic signals, scaffolds, and an appropriate mechanical environment. Although differentiated cells from the tissue in question can be used, most cellular research focuses on the use of mesenchymal stem cells. These can be retrieved from many different tissues, and one unresolved question is the degree to which the origin of the cells matters. Embryonic and induced pluripotent stem cells are also under investigation. Morphogenetic signals are most frequently supplied by individual recombinant growth factors or native mixtures provided by, for example, platelet-rich plasma; mesenchymal stem cells are also a rich source of trophic factors. Obstacles to the sustained delivery of individual growth factors can be addressed by gene transfer or smart scaffolds, but we still lack detailed, necessary information on which delivery profiles are needed. Scaffolds may be based on natural products, synthetic materials, or devitalized extracellular matrix. Strategies to combine these components to regenerate tissue can follow traditional tissue engineering practices, but these are costly, cumbersome, and not well suited to treating large numbers of individuals. More expeditious approaches make full use of intrinsic biological processes in vivo to avoid the need for ex vivo expansion of autologous cells and multiple procedures. Clinical translation remains a bottleneck.

Characterization and evaluation of the differentiation ability of human adipose-derived stem cells growing in scaffold-free suspension culture

BACKGROUND AIMS

Human adipose-derived stem cells (hADSCs) have become a popular stem cell source because of their abundant supplies, high differentiation ability and the fact that they present few ethical concerns. Suspension culture, a type of three-dimensional culture, is a more suitable model for mimicking cell-cell and cell-extracellular matrix interactions than is two-dimensional monolayer culture. The aim of this study was to determine the effects of suspension culture on the viability and differentiation potential of hADSCs.

METHODS

Different densities of hADSCs were cultured in ultra-low-attachment surface plates. The morphology and mean diameter of the resultant aggregates were determined by means of microscopy. The viability of the aggregates was evaluated with the use of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt, lactate dehydrogenase and live/dead assays. To detect osteogenesis, chondrogenesis and adipogenesis in hADSCs in suspension culture, cell aggregates were stained to determine cell function, and the expression of specific markers was evaluated through the use of real-time reverse transcriptase-polymerase chain reaction.

RESULTS

The hADSCs remained viable in suspension culture and formed cell aggregates. The diameter of the majority of the aggregates was in the range of 50-200 μm, regardless of cell density. The aggregation of the hADSCs served to maintain cell survival. In addition, the results of the histomorphometric and gene expression analyses showed that the hADSCs were more efficiently induced to differentiate into osteoblasts, chondrocytes and adipocytes in suspension culture than in two-dimensional monolayer culture.

CONCLUSIONS

Suspension culture can be used to maintain cell viability and contributes to the effective differentiation of hADSCs, providing an alternative cell growth strategy for application to stem cell-based regenerative medicine.