Multipotent mesenchymal stromal cells in articular diseases

Intra Articular Injection of Autologous Microfat and Platelets-Rich Plasma in the Treatment of Wrist Osteoarthritis: A Pilot Study

No injection treatment has been proven to be effective in wrist osteoarthritis. When conservative measures fail, its management involves invasive surgery. Emergence of biotherapies based on adipose derived stem cells (ADSC) offers promising treatments for chondral degenerative diseases. Microfat (MF) and platelets-rich plasma (PRP) mixture, rich in growth factors and ADSC could be a minimally invasive injectable option in the treatment of wrist osteoarthritis. The aim of this uncontrolled prospective study was to evaluate the safety of a 4 mL autologous MF-PRP intra-articular injection, performed under local anesthesia. The secondary purpose was to describe the clinical and MRI results at 12 months of follow-up. Patients' data collected were: occurrence of adverse effects, Visual analog scale (VAS), Disabilities of the Arm, Shoulder and Hand score (DASH) and Patient-Rated Wrist Evaluation (PRWE) scores, wrist strength, wrist range of motion and 5-level satisfaction scale. No serious adverse event was recorded. A statistically significant decrease in pain, DASH, PRWE and force was observed at each follow-up. Our preliminary results suggest that intra-articular autologous MF and PRP injection may be a new therapeutic strategy for wrist osteoarthritis resistant to medical symptomatic treatment prior to surgical interventions.

Intra-Articular Injection of Autologous Microfat and Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Double-Blind Randomized Comparative Study

PURPOSE

To compare a single abdominal microfat (MF) injection mixed or not with platelet-rich plasma (PRP) Low Dose (LD) or High Dose (HD) in order to improve MRI parameters, alleviate pain and enhance functional capacity in knee osteoarthritis.

METHODS

Patients with symptomatic grade 2 to 4 knee osteoarthritis according to the International Cartilage Repair Society MRI classification were selected. They were prospectively assessed at baseline and at 3 and 6 months of follow-up. The primary endpoint was change in the maximum of value of cartilage relaxation time in T2 mapping sequences (T2max) at 3 months. Secondary endpoints were MRI grade severity and joint space assessment, Western Ontario and McMaster Universities Arthritis Index score, pain evaluation, knee range of motion, and patients' satisfaction. Adverse events were also collected. The complete cell counts and growth factors content of injected products were assessed to analyze their potential relationship with MRI and clinical outcomes.

RESULTS

Three groups of 10 patients received a single injection of 10 cc of a mix (1:1) containing MF-Saline, MF-PRP LD or MF-PRP HD. T2max did not change significantly over the time for any of the groups. All treatments significantly improved knee functional status and symptom relief at 3 and 6 months. All patients were responders in the MF/PRP HD at 3 months and significantly higher compared to MF/PRP LD. Half of the injected PRP in the MF/PRP LD group displayed red blood cell contamination of over 8%, which was correlated with an impairment of T2max.

CONCLUSION

A single intra-articular injection of MF with or without PRP is safe and may offer a significant clinical improvement in patients with osteoarthritis.

LEVEL OF EVIDENCE

2; randomized double-blind comparative parallel-group trial (RCT No.: NCT04352075).

Human adipose-derived mesenchymal progenitor cells plus microfracture and hyaluronic acid for cartilage repair: a Phase IIa trial

Aim: This study aimed to preliminarily evaluate the safety and efficacy of human adipose-derived mesenchymal progenitor cells (haMPCs) in combination with microfracture and hyaluronic acid (HA) for treating cartilage defects. Materials & methods: A total of 30 patients with medial femoro-tibial condylar cartilage defects were randomized into three groups: arthroscopic microfracture group and normal saline injection, arthroscopic microfracture and intra-articular injection of HA, or arthroscopic microfracture in combination with intra-articular injection of HA and haMPCs. Results & conclusions: The data demonstrated that intra-articular injection of haMPCs plus microfracture and HA is a safe procedure to improve joint function in patients with knee cartilage defects. These findings provide an impetus for future research on this treatment. ClinicalTrials.gov Identifier: NCT02855073.

Efficacy and safety of culture-expanded, mesenchymal stem/stromal cells for the treatment of knee osteoarthritis: a systematic review protocol

Background

Osteoarthritis is a progressive multifactorial condition of the musculoskeletal system with major symptoms including pain, loss of function, damage of articular cartilage and other tissues in the affected area. Knee osteoarthritis imposes major individual and social burden, especially with the cost and complexity of surgical interventions. Mesenchymal stem/stromal cells have been indicated as a treatment for degenerative musculoskeletal conditions given their capacity to differentiate into tissues of the musculoskeletal system.

Methods

A systematic search will be conducted in Medline, Embase, Cochrane Library, Scopus and relevant trial databases of English, Japanese, Korean, German, French, Italian, Spanish and Portuguese language papers published or in press to June 2018, with no restrictions on publication year applied. References will be screened and assessed for eligibility by two independent reviewers as per PRISMA guidelines. Cohort, cross-sectional or case controlled studies will be included for the analysis. Data extraction will be conducted using a predefined template and quality of evidence assessed. Statistical summaries and meta-analyses will be performed as necessary.

Discussion

Results will be published in relevant peer-reviewed scientific journals and presented at national or international conferences by the investigators.

Trial registration

The protocol was registered on the PROSPERO international prospective register of systematic reviews prior to commencement, CRD42018091763.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1070-8) contains supplementary material, which is available to authorized users.

Pentosan polysulfate binds to STRO-1+ mesenchymal progenitor cells, is internalized, and modifies gene expression: a novel approach of pre-programing stem cells for therapeutic application requiring their chondrogenesis

BACKGROUND

The pharmaceutical agent pentosan polysulfate (PPS) is known to induce proliferation and chondrogenesis of mesenchymal progenitor cells (MPCs) in vitro and in vivo. However, the mechanism(s) of action of PPS in mediating these effects remains unresolved. In the present report we address this issue by investigating the binding and uptake of PPS by MPCs and monitoring gene expression and proteoglycan biosynthesis before and after the cells had been exposed to limited concentrations of PPS and then re-established in culture in the absence of the drug (MPC priming).

METHODS

Immuno-selected STRO-1+ mesenchymal progenitor stem cells (MPCs) were prepared from human bone marrow aspirates and established in culture. The kinetics of uptake, shedding, and internalization of PPS by MPCs was determined by monitoring the concentration-dependent loss of PPS media concentrations using an enzyme-linked immunosorbent assay (ELISA) and the uptake of fluorescein isothiocyanate (FITC)-labelled PPS by MPCs. The proliferation of MPCs, following pre-incubation and removal of PPS (priming), was assessed using the Wst-8 assay method, and proteoglycan synthesis was determined by the incorporation of 35SO4 into their sulphated glycosaminoglycans. The changes in expression of MPC-related cell surface antigens of non-primed and PPS-primed MPCs from three donors was determined using flow cytometry. RNA sequencing of RNA isolated from non-primed and PPS-primed MPCs from the same donors was undertaken to identify the genes altered by the PPS priming protocol.

RESULTS

The kinetic studies indicated that, in culture, PPS rapidly binds to MPC surface receptors, followed by internalisation and localization within the nucleus of the cells. Following PPS-priming of MPCs and a further 48 h of culture, both cell proliferation and proteoglycan synthesis were enhanced. Reduced expression of MPC-related cell surface antigen expression was promoted by the PPS priming, and RNA sequencing analysis revealed changes in the expression of 42 genes.

CONCLUSION

This study has shown that priming of MPCs with low concentrations of PPS enhanced chondrogenesis and MPC proliferation by modifying their characteristic basal gene and protein expression. These findings offer a novel approach to re-programming mesenchymal stem cells for clinical indications which require the repair or regeneration of cartilaginous tissues such as in osteoarthritis and degenerative disc disease.

Adipose Mesenchymal Stromal Cell-Based Therapy for Severe Osteoarthritis of the Knee: A Phase I Dose-Escalation Trial

: Osteoarthritis (OA) is the most widespread musculoskeletal disorder in adults. It leads to cartilage damage associated with subchondral bone changes and synovial inflammation, causing pain and disability. The present study aimed at evaluating the safety of a dose-escalation protocol of intra-articular injected adipose-derived stromal cells (ASCs) in patients with knee OA, as well as clinical efficacy as secondary endpoint. A bicentric, uncontrolled, open phase I clinical trial was conducted in France and Germany with regulatory agency approval for ASC expansion procedure in both countries. From April 2012 to December 2013, 18 consecutive patients with symptomatic and severe knee OA were treated with a single intra-articular injection of autologous ASCs. The study design consisted of three consecutive cohorts (six patients each) with dose escalation: low dose (2 × 10(6) cells), medium dose (10 × 10(6)), and high dose (50 × 10(6)). The primary outcome parameter was safety evaluated by recording adverse events throughout the trial, and secondary parameters were pain and function subscales of the Western Ontario and McMaster Universities Arthritis Index. After 6 months of follow-up, the procedure was found to be safe, and no serious adverse events were reported. Four patients experienced transient knee joint pain and swelling after local injection. Interestingly, patients treated with low-dose ASCs experienced significant improvements in pain levels and function compared with baseline. Our data suggest that the intra-articular injection of ASCs is a safe therapeutic alternative to treat severe knee OA patients. A placebo-controlled double-blind phase IIb study is being initiated to assess clinical and structural efficacy.

SIGNIFICANCE

Although this phase I study included a limited number of patients without a placebo arm, it showed that local injection of autologous adipose-derived stem cells was safe and well tolerated in patients with knee osteoarthritis. This study also provides encouraging preliminary evidence of efficacy. Larger and controlled long-term studies are now mandatory to confirm whether this new strategy of cell therapy can improve pain and induce structural benefit in osteoarthritis.

The role of stem cell therapies in degenerative lumbar spine disease: a review

Degenerative conditions of the lumbar spine are extremely common. Ninety percent of people over the age of 60 years have degenerative change on imaging; however, only a small minority of people will require spine surgery (Hicks et al. Spine (Phila Pa 1976) 34(12):1301-1306, 2009). This minority, however, constitutes a core element of spinal surgery practice. Whilst the patient outcomes from spinal surgeries have improved in recent years, some patients will remain with pain and disability despite technically successful surgery. Advances in regenerative medicine and stem cell therapies, particularly the use of mesenchymal stem cells and allogeneic mesenchymal precursor cells, have led to numerous clinical trials utilising these cell-based therapies to treat degenerative spinal conditions. Through cartilage formation and disc regeneration, fusion enhancement or via modification of pain pathways, stem cells are well suited to enhance spinal surgery practice. This review will focus on the outcomes of lumbar spinal procedures and the role of stem cells in the treatment of degenerative lumbar conditions to enhance clinical practice. The current status of clinical trials utilising stem cell therapies will be discussed, providing clinicians with an overview of the various cell-based treatments likely to be available to patients in the near future.

Therapeutic properties of mesenchymal stem cells for autism spectrum disorders

Recent studies of autism spectrum disorders (ASD) highlight hyperactivity of the immune system, irregular neuronal growth and increased size and number of microglia. Though the small sample size in many of these studies limits extrapolation to all individuals with ASD, there is mounting evidence of both immune and nervous system related pathogenesis in at least a subset of patients with ASD. Given the disturbing rise in incidence rates for ASD, and the fact that no pharmacological therapy for ASD has been approved by the Food and Drug Administration (FDA), there is an urgent need for new therapeutic options. Research in the therapeutic effects of mesenchymal stem cells (MSC) for other immunological and neurological conditions has shown promising results in preclinical and even clinical studies. MSC have demonstrated the ability to suppress the immune system and to promote neurogenesis with a promising safety profile. The working hypothesis of this paper is that the potentially synergistic ability of MSC to modulate a hyperactive immune system and its ability to promote neurogenesis make it an attractive potential therapeutic option specifically for ASD. Theoretical mechanisms of action will be suggested, but further research is necessary to support these hypothetical pathways. The choice of tissue source, type of cell, and most appropriate ages for therapeutic intervention remain open questions for further consideration. Concern over poor regulatory control of stem cell studies or treatment, and the unique ethical challenges that each child with ASD presents, demands that future research be conducted with particular caution before widespread use of the proposed therapeutic intervention is implemented.

Anti-inflammatory role and immunomodulation of mesenchymal stem cells in systemic joint diseases: potential for treatment

INTRODUCTION

Mesenchymal stem cells (MSCs) are multipotent stromal cells characterized by their ability to differentiate into adipocytes, chondrocytes, osteocytes and a number of other lineages. Investigation into their use has increased in recent years as characterization of their immunomodulatory properties has developed, and their role in the pathophysiology of joint disease has been suggested.

AREAS COVERED

MSCs demonstrate immunosuppressive functionality by suppressing T- and B-cell responses following activation by cytokines such as IL-6 and IL-1α. They also can be induced to exert pro-inflammatory effects in the presence of acute inflammatory environment due to the actions of TNF-α and IFN-γ. In inflammatory joint diseases such as rheumatoid arthritis, MSCs in bone marrow migrate to joints by a TNF-α-dependent mechanism and may be in part responsible for the disease process. MSCs have also been demonstrated in increased numbers in periarticular tissues in osteoarthritis, which may reflect an attempt at joint regeneration.

EXPERT OPINION

Clinical applications for MSCs have shown promise in a number of inflammatory and autoimmune disorders. Future work is likely to further reveal the immunosuppressive characteristics of MSCs, their role in the pathophysiology of joint diseases and provide the basis for new avenues for treatment.

Platelet lysate 3D scaffold supports mesenchymal stem cell chondrogenesis: an improved approach in cartilage tissue engineering

Articular lesions are still a major challenge in orthopedics because of cartilage's poor healing properties. A major improvement in therapeutics was the development of autologous chondrocytes implantation (ACI), a biotechnology-derived technique that delivers healthy autologous chondrocytes after in vitro expansion. To obtain cartilage-like tissue, 3D scaffolds are essential to maintain chondrocyte differentiated status. Currently, bioactive 3D scaffolds are promising as they can deliver growth factors, cytokines, and hormones to the cells, giving them a boost to attach, proliferate, induce protein synthesis, and differentiate. Using mesenchymal stem cells (MSCs) differentiated into chondrocytes, one can avoid cartilage harvesting. Thus, we investigated the potential use of a platelet-lysate-based 3D bioactive scaffold to support chondrogenic differentiation and maintenance of MSCs. The MSCs from adult rabbit bone marrow (n = 5) were cultivated and characterized using three antibodies by flow cytometry. MSCs (1 × 10(5)) were than encapsulated inside 60 µl of a rabbit platelet-lysate clot scaffold and maintained in Dulbecco's Modified Eagle Medium Nutrient Mixture F-12 supplemented with chondrogenic inductors. After 21 days, the MSCs-seeded scaffolds were processed for histological analysis and stained with toluidine blue. This scaffold was able to maintain round-shaped cells, typical chondrocyte metachromatic extracellular matrix deposition, and isogenous group formation. Cells accumulated inside lacunae and cytoplasm lipid droplets were other observed typical chondrocyte features. In conclusion, the usage of a platelet-lysate bioactive scaffold, associated with a suitable chondrogenic culture medium, supports MSCs chondrogenesis. As such, it offers an alternative tool for cartilage engineering research and ACI.

Enhancing osteoconduction of PLLA-based nanocomposite scaffolds for bone regeneration using different biomimetic signals to MSCs

In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic "extracellular matrix"-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA)-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT), micro-hydroxyapatite particles (HA), and BMP2, and treated with plasma (PT), to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs) were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization.

Tumor risk by tissue engineering: cartilaginous differentiation of mesenchymal stem cells reduces tumor growth

OBJECTIVE

Implantation of autologous chondrocytes (AC) is a promising option for the treatment of cartilage defects, but problems with cell harvesting, dedifferentiation, or the donor age limit the clinical outcome. Mesenchymal stem cells (MSC) gain much interest because of their simple isolation and multipotential differentiation capacity along with their immunosuppressive properties. The latter might introduce tumor manifestation. The influence of undifferentiated and chondrogenically differentiated MSC or AC on tumor growth and metastasis formation was investigated in a murine melanoma model.

METHODS

Allogeneic melanoma cells and either syngeneic MSC (C3H10T1/2, transduced with enhanced green fluorescent protein gene) or AC were co-injected at a distance of 3 cm into the contra lateral groins of five mice/group, and evaluated macroscopically and histologically after 4 weeks.

RESULTS

Undifferentiated MSC migrated to the tumor site and induced strong tumor growth and metastasis formation. Even avital MSC promoted tumor growth and spreading, but insignificantly without detectable MSC at the tumor site. Chondrogenically differentiated MSC did not migrate and had a significantly lower impact on tumor growth and spreading; AC had no measurable influence on melanoma cells.

CONCLUSIONS

Our data suggest that differentiation of MSC reduces MSC-dependent promotion of latent tumors and that native AC do not introduce any increased risk of tumor growth. The question of how far MSC should be differentiated prior to clinical application should be addressed in further studies.

Pentosan polysulfate promotes proliferation and chondrogenic differentiation of adult human bone marrow-derived mesenchymal precursor cells

INTRODUCTION

This study was undertaken to determine whether the anti-osteoarthritis drug pentosan polysulfate (PPS) influenced mesenchymal precursor cell (MPC) proliferation and differentiation.

METHODS

Human MPCs were maintained in monolayer, pellet or micromass cultures (MMC) for up to 10 days with PPS at concentrations of 0 to 20 microg/ml. MPC viability and proliferation was assessed using the WST-1 assay and 3H-thymidine incorporation into DNA, while apoptosis was monitored by flow cytometry. Proteoglycan (PG) biosynthesis was determined by 35SO42- incorporation and staining with Alcian blue. Proteoglycan and collagen type I and collagen type II deposition in pellet cultures was also examined by Toluidine blue and immunohistochemical staining, respectively. The production of hyaluronan (HA) by MPCs in MMC was assessed by ELISA. The relative outcome of PPS, HA, heparin or dextran sulfate (DS) on PG synthesis was compared in 5-day MMC. Gene expression of MPCs in 7-day and 10-day MMC was examined using real-time PCR. MPC differentiation was investigated by co-culturing with PPS in osteogenic or adipogenic inductive culture media for 28 days.

RESULTS

Significant MPC proliferation was evident by day 3 at PPS concentrations of 1 to 5 microg/ml (P < 0.01). In the presence of 1 to 10 microg/ml PPS, a 38% reduction in IL-4/IFNgamma-induced MPC apoptosis was observed. In 5-day MMC, 130% stimulation of PG synthesis occurred at 2.5 microg/ml PPS (P < 0.0001), while 5.0 microg/ml PPS achieved maximal stimulation in the 7-day and 10-day cultures (P < 0.05). HA and DS at > or = 5 microg/ml inhibited PG synthesis (P < 0.05) in 5-day MMC. Collagen type II deposition by MMC was significant at > or = 0.5 microg/ml PPS (P < 0.001 to 0.05). In MPC-PPS pellet cultures, more PG, collagen type II but less collagen type I was deposited than in controls. Real-time PCR results were consistent with the protein data. At 5 and 10 microg/ml PPS, MPC osteogenic differentiation was suppressed (P < 0.01).

CONCLUSIONS

This is the first study to demonstrate that PPS promotes MPC proliferation and chondrogenesis, offering new strategies for cartilage regeneration and repair in osteoarthritic joints.

Natural bone collagen scaffold combined with autologous enriched bone marrow cells for induction of osteogenesis in an ovine spinal fusion model

Autologous bone graft, the standard of bone grafting in achieving spinal fusion, is associated with several limitations and complications. The use of bone marrow cells (BMCs) as a potential cell source for spinal fusion, combined with a suitable scaffold to promote bone formation, may be a better choice. The aims of this study were to evaluate the efficacy of natural bone collagen scaffold (NBCS) combined with autologous-enriched BMCs for induction of osteogenesis in vitro and in vivo. Ovine-enriched BMCs were co-cultured with NBCS for 1, 2, 3, and 4 weeks to investigate whether NBCS would support the population expansion and differentiation of enriched BMCs. Using an ovine interbody fusion model, NBCS seeded with autologous enriched BMCs was implanted into the lumbar disc space. Fusion outcomes were compared with the use of the autograft, NBCS without BMCs, and BMCs without NBCS. In vitro results demonstrated that NBCS facilitated the population expansion and differentiation of ovine-enriched BMCs, promoting the expression of collagen type I and the formation of a mineralized matrix. The use of NBCS combined with enriched BMCs in vivo enhanced the spinal fusion rate (6 of 6 at 10 week) (p < 0.05), the biomechanical stiffness of fusion masses, and bone volume at the fusion site (p < 0.05). Histological findings also revealed that a combination of NBCS and BMCs induced new bone formation that integrated well with host bone tissue. In conclusion, NBCS is an effective scaffold that supports ovine-enriched BMCs. The combination of NBCS and BMCs may be a useful alternative for autograft in induction of spinal fusion.

Subcutaneous graft of D1 mouse mesenchymal stem cells leads to the formation of a bone-like structure

Mesenchymal stem cells (MSC) are capable of both self-renewal and multi-lineage differentiation into mesoderm-type cells such as osteoblasts, chondrocytes, adipocytes and myocytes. Together the multipotent nature of MSCs and the facility to expand them in vitro make these cells ideal resources for regenerative medicine, particularly for bone reconstruction, and therefore research efforts focused on defining efficient protocols for directing their differentiation into the requisite lineage. Despite much progress in identifying mechanisms and factors that direct and control in vitro osteogenic differentiation of MSCs, a rapid and simple model to evaluate in vivo tissue formation is still lacking. Here, we describe the unique capacity of the murine bone marrow-derived D1 MSC cell line, which differentiates in vitro into at least three cell lineages, to form in vivo a structure resembling bone. This bone-like structure was obtained after subcutaneous grafting of D1 cells into immunocompetent mice without the need of neither an osteogenic factor nor scaffold material. These data allow us to propose this cell model as a tool for exploring in vivo the mechanisms and/or factors that govern and potentially regulate osteogenesis.

[Mesenchymal stem cells in arthritis]

While one of the major achievements of the 20th century was prolonging life expectancy in developed countries, the main challenge of the 21st century is to improve the quality of life of the aging population. Aging is associated with a progressive reduction of organ system function. Therefore, regenerative medicine will be one of the major developing fields of medicine. This new medical field does not only apply to aging but also to all degenerative diseases, such as arthritis and degenerative joint disease, which lead to progressive degeneration of mesenchymal tissues such as bone and cartilage. The discovery of pluripotent mesenchymal stem cells (MSCs) offers a promising alternative to surgery for non-invasive regenerative therapies of mesenchymal tissues. This review focuses on the characterization and potential application of MSCs in the regeneration of damaged joints.

Multipotent mesenchymal stromal cells and rheumatoid arthritis: risk or benefit?

Multipotent mesenchymal stromal cells (MSCs) have raised interest mainly because of cartilage/bone differentiation potential which is now partly eclipsed by their capacity to counteract inflammation and suppress host immune responses as well as to prevent fibrosis. MSCs have been identified within joint tissues including synovium, cartilage, subchondral bone, periosteum or adipose tissue. They are characterized by their phenotype and their ability to differentiate into three lineages, chondrocytes, osteoblasts and adipocytes. MSCs have also paracrine effects through the secretion of a number of cytokines and growth factors. This may explain the trophic effects that may be of therapeutic value for rheumatic diseases including OA and RA. On the other hand, MSCs have been associated with tumour growth. MSCs migrate to the tumour stroma, express chemokines involved in the attraction of carcinoma cells in metastasis. Indeed, the aim of this review is not only to focus on new potential therapeutic applications in osteo-articular diseases, but also to assess the potential risk of MSC-based cell therapy.

Tissue engineering in the rheumatic diseases

Diseases such as degenerative or rheumatoid arthritis are accompanied by joint destruction. Clinically applied tissue engineering technologies like autologous chondrocyte implantation, matrix-assisted chondrocyte implantation, or in situ recruitment of bone marrow mesenchymal stem cells target the treatment of traumatic defects or of early osteoarthritis. Inflammatory conditions in the joint hamper the application of tissue engineering during chronic joint diseases. Here, most likely, cartilage formation is impaired and engineered neocartilage will be degraded. Based on the observations that mesenchymal stem cells (a) develop into joint tissues and (b) in vitro and in vivo show immunosuppressive and anti-inflammatory qualities indicating a transplant-protecting activity, these cells are prominent candidates for future tissue engineering approaches for the treatment of rheumatic diseases. Tissue engineering also provides highly organized three-dimensional in vitro culture models of human cells and their extracellular matrix for arthritis research.

Temperature and calcium ions affect aggregation of mesenchymal stem cells in phosphate buffered saline

Bone marrow-derived mesenchymal stem cells (MSC) are being extensively studied as potential therapeutic agents for various diseases and have demonstrated tremendous promise to date. To reduce immunological and inflammatory reaction upon delivery of MSC in situ, the cells are often suspended in protein-free and nutrient-poor buffered saline solution at high titers and kept on ice (0 degrees C) until completion of the transplantation procedure. This study investigated the effects of suspending MSC (5 x 10(6) cells/mL) in phosphate buffered saline (PBS) with and without calcium, over a time course of 90 and 180 min, at temperatures of 0 and 37 degrees C. The results at 0 degrees C showed a small but significant decrease in cell viability within calcium-free PBS after 180 min, whereas no significant changes in cell viability were observed with PBS containing calcium. Additionally, it was observed that significant aggregation of MSC into cellular clumps occurred when incubated in PBS at 0 degrees C, with a higher degree of aggregation occurring under calcium-free conditions. By contrast at 37 degrees C, there was a more pronounced decrease in cell viability after 90 and 180 min, but lesser aggregation of MSC both in the presence and absence of calcium. The aggregation of MSC into cellular clumps could pose an embolic hazard if delivered into the arterial vasculature in cardiac applications, can clog-up injection or infusion catheters utilized for cell delivery during surgery, and can also possibly reduce the overall efficacy of transplantation therapy.