The potential role of adult stem cells in the management of the rheumatic diseases

Teaming up to overcome challenges toward translation of new therapeutics for osteoarthritis

As a leading global cause of musculoskeletal-related disability, osteoarthritis (OA) represents a public health urgency. Understanding of disease pathogenesis has advanced substantially in the past decade, yet no disease-modifying therapeutics have advanced to the clinic. To address this challenge, the CARE-AP (Cartilage Repair strategies to alleviate Arthritis Pain) collaborative research team was convened to bring together relevant multidisciplinary expertise and perspectives from across the VA research community nationwide. The first CARE-AP Annual Research Symposium took place (virtually) in February 2022 with roughly 90 participants. A number of innovative and therapeutic strategies were discussed, including siRNA approaches coupled with novel nanoparticle-based delivery systems, cellular engineering approaches to develop reparative cells that can probe the joint environment and respond to disease-specific cues, and novel biofabrication techniques to improve tissue engineering and effect "biological joint replacement." In addition, challenges and advances in rehabilitation approaches, imaging outcomes, and clinical studies were presented, which were integrated into a framework of recommendations for running "preclinical trials" to improve successful clinical translation.

A comprehensive review on the role of mesenchymal stromal/stem cells in the management of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease with systemic manifestations. Although the success of immune modulatory drug therapy is considerable, about 40% of patients do not respond to treatment. Mesenchymal stromal/stem cells (MSCs) have been demonstrated to have therapeutic potential for inflammatory diseases.

AREAS COVERED

This review provides an update on RA disease and on pre-clinical and clinical studies using MSCs from bone marrow, umbilical cord, adipose tissue, and dental pulp, to regulate the immune response. Moreover, the clinical use, safety, limitations, and future perspective of MSCs in RA are discussed. Using the PubMed database and ClincalTrials.gov, peer-reviewed full-text papers, abstracts and clinical trials were identified from 1985 through to April 2023.

EXPERT OPINION

MSCs demonstrated a satisfactory safety profile and potential for clinical efficacy. However, it is mandatory to deepen the investigations on how MSCs affect the proinflammatory deregulated RA patients' cells. MSCs are potentially good candidates for severe RA patients not responding to conventional therapies but a long-term follow-up after stem cells treatment and standardized protocols are needed. Future research should focus on well-designed multicenter randomized clinical trials with adequate sample sizes and properly selected patients satisfying RA criteria for a valid efficacy evaluation.

Characteristics of Pooled Wharton's Jelly Mesenchymal Stromal Cells (WJ-MSCs) and their Potential Role in Rheumatoid Arthritis Treatment

INTRODUCTION

Mesenchymal stromal cells (MSC) from Wharton's jelly of umbilical cord is primitive and serve as an inexhaustible source of stem cells with greater potential in clinics. The existence of heterogeneity among the donor MSCs makes it difficult to predict the properties and clinical outcome of WJ-MSCs. We developed a strategy to minimize the donor to donor heterogeneity and produce consistency in biological properties by pooling three individual donors WJ-MSCs. Further, evaluated the effectiveness of the pooled MSCs in regulating the disease severity of Rheumatoid arthritis (RA) in animal models.

METHODS

WJ-MSCs were isolated from umbilical cord obtained from different donors, characterised and pooled based on the gender of baby. The biological properties of the pooled WJ-MSCs were compared to the individual WJ-MSCs. Further, the pooled WJ-MSCs were analysed for their safety profile in both in vitro and in vivo settings. The efficiency of pooled WJ-MSCs in regulating RA pathogenesis was also analysed in mice models of Collagen induced arthritis (CIA).

RESULTS

We identified differences in proliferation capacity, pro inflammatory gene expression levels among individual WJ-MSCs isolated from different donors and the variation is also attributed to gender difference. WJ-MSCs pooled and cultured from different donor's exhibit all the MSC characteristics and exhibited superior immunosuppressive capabilities. In the in vivo toxicity study, pooled MSCs are found to be safe, and further in the RA preclinical studies, they were found to decrease the disease severity in these animals.

CONCLUSIONS

Pooled WJ-MSCs reduces heterogeneity of individual donors and have superior immunosuppressive property. It is also effective in reducing the disease severity in the experimental animal models of RA.

Role of PD-L1 in licensing immunoregulatory function of dental pulp mesenchymal stem cells

Background

Dental pulp stem cells (DPSCs) are low immunogenic and hold immunomodulatory properties that, along with their well-established multi-potency, might enhance their potential application in autoimmune and inflammatory diseases. The present study focused on the ability of DPSCs to modulate the inflammatory microenvironment through PD1/PD-L1 pathway.

Methods

Inflammatory microenvironment was created in vitro by the activation of T cells isolated from healthy donors and rheumatoid arthritis (RA) patients with anti-CD3 and anti-CD28 antibodies. Direct and indirect co-cultures between DPSCs and PBMCs were carried out to evaluate the activation of immunomodulatory checkpoints in DPSCs and the inflammatory pattern in PBMCs.

Results

Our data suggest that the inflammatory stimuli trigger DPSCs immunoregulatory functions that can be exerted by both direct and indirect contact. As demonstrated by using a selective PD-L1 inhibitor, DPSCs were able to activate compensatory pathways targeting to orchestrate the inflammatory process by modulating pro-inflammatory cytokines in pre-activated T lymphocytes. The involvement of PD-L1 mechanism was also observed in autologous inflammatory status (pulpitis) and after direct exposure to pre-activated T cells from RA patients suggesting that immunomodulatory/anti-inflammatory properties are strictly related to their stemness status.

Conclusions

Our findings point out that the communication with the inflammatory microenvironment is essential in licensing their immunomodulatory properties.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02664-4.

Comparative study between human mesenchymal stem cells and etanercept as immunomodulatory agents in rat model of rheumatoid arthritis

To compare human adipose tissue mesenchymal stem cells (AT-MSCs) and etanercept as immunomodulatory agents for collagen-induced arthritis (CIA). CIA was induced by rats' immunization with collagen type II (CII) in complete Freund's adjuvant in days 0 and 7. Before the onset of CIA, prevention group received five doses of AT-MSCS intraperitoneally. After establishment of arthritis, rats received either five doses of AT-MSCs or phosphate-buffered saline (PBS) intraperitoneally or six doses of etanercept subcutaneously. Clinical and histopathological evaluation were performed in all groups; serum levels of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and anti-collagen II were assessed by enzyme-linked immunosorbent assay (ELISA). A total percent of autoreactive T and regulatory T (Treg) cells were quantified using spleen immune histochemical analysis. AT-MSCs were able to delay the onset of CIA, suppress the ongoing clinical and histopathological signs, decrease serum levels of TNF-α and anti-collagen type II, and downregulate the autoreactive T cells as etanercept. AT-MSCs were more potent in Treg cells upregulation, producing high serum levels of IL10. AT-MSCs might have a therapeutic effect in CIA via their potency in immune cell education, representing an effective new promising approach in rheumatoid arthritis in human.

Evidence-based indications of platelet-rich plasma therapy

Introduction: Platelet-rich plasma (PRP) is an autologous blood-derived product that contains platelet concentrations at least 2/3 times above the normal level and includes platelet-related growth factors. The concept of PRP began in the 1970s in the field of hematology to treat patients with thrombocytopenia. In the 1980s and 1990s, PRP began to be used in surgical procedures such as maxillofacial surgery and plastic surgery. Since then, PRP had been used in orthopedic procedures, cardiac surgery, sports injuries, plastic surgery, gynecology, urology, and more recently in medical esthetics. Areas covered: This review analyzes the mechanisms of action, current indications, clinical evidence, safety and future directions of PRP in the management of various medical conditions. The literature search methodology included using medical subject headings terms to search in PubMed. Articles used were screened and critically appraised by the coauthors of this review. Expert Opinion: Platelet-rich plasma is a therapeutic option used to treat many medical conditions. PRP could be used alone or in combination with other procedures. The effectiveness and safety of PRP has been demonstrated in many medical scenarios, however there is limited availability of large randomized clinical trials.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles - Silver Linings for Cartilage Regeneration?

As the world's population is aging, the incidence of the degenerative disease Osteoarthritis (OA) is increasing. Current treatment options of OA focus on the alleviation of the symptoms including pain and inflammation rather than on restoration of the articular cartilage. Cell-based therapies including the application of mesenchymal stromal cells (MSCs) have been a promising tool for cartilage regeneration approaches. Due to their immunomodulatory properties, their differentiation potential into cells of the mesodermal lineage as well as the plurality of sources from which they can be isolated, MSCs have been applied in a vast number of studies focusing on the establishment of new treatment options for Osteoarthritis. Despite promising outcomes in vitro and in vivo, applications of MSCs are connected with teratoma formation, limited lifespan of differentiated cells as well as rejection of the cells after transplantation, highlighting the need for new cell free approaches harboring the beneficial properties of MSCs. It has been demonstrated that the regenerative potential of MSCs is mediated by the release of paracrine factors rather than by differentiation into cells of the desired tissue. Besides soluble factors, extracellular vesicles are the major component of a cell's secretome. They represent novel mechanisms by which (pathogenic) signals can be communicated between cell types as they deliver bioactive molecules (nucleic acids, proteins, lipids) from the cell of origin to the target cell leading to specific biological processes upon uptake. This review will give an overview about extracellular vesicles including general characteristics, isolation methods and characterization approaches. Furthermore, the role of MSC-derived extracellular vesicles in in vitro and in vivo studies for cartilage regeneration will be summarized with special focus on transported miRNA which either favored the progression of OA or protected the cartilage from degradation. In addition, studies will be reviewed investigating the impact of MSC-derived extracellular vesicles on inflammatory arthritis. As extracellular vesicles are present in all body fluids, their application as potential biomarkers for OA will also be discussed in this review. Finally, studies exploring the combination of MSC-derived extracellular vesicles with biomaterials for tissue engineering approaches are summarized.

Mesenchymal stem cell markers in periodontal tissues and periapical lesions

INTRODUCTION

Mesenchymal stem cells (MSCs) are characterized by the potential to differentiate into multiple cell lineages, high proliferation rates, and self-renewal capacity, in addition to the ability to maintain their undifferentiated state. These cells have been identified in physiological oral tissues such as pulp tissue, dental follicle, apical papilla and periodontal ligament, as well as in pathological situations such as chronic periapical lesions (CPLs). The criteria used for the identification of MSCs include the positive expression of specific surface antigens, with CD73, CD90, CD105, CD44, CD146, STRO-1, CD166, NANOG and OCT4 being the most specific for these cells.

AIM

The aim of this review was to explore the literature on markers able to identify MSCs as well as the presence of these cells in the healthy periodontal ligament and CPLs, highlighting their role in regenerative medicine and implications in the progression of these lesions.

METHODS

Narrative literature review searching the PubMed and Medline databases. Articles published in English between 1974 and 2020 were retrieved.

CONCLUSION

The included studies confirmed the presence of MSCs in the healthy periodontal ligament and in CPLs. Several surface markers are used for the characterization of these cells which, although not specific, are effective in cell recognition. Mesenchymal stem cells participate in tissue repair, exerting anti- inflammatory, immunosuppressive and proangiogenic effects, and are therefore involved in the progression and attenuation of CPLs or even in the persistence of these lesions.

Haematopoietic stem cell transplantation in systemic sclerosis: Challenges and perspectives

Systemic Sclerosis is chronic progressive autoimmune disease, characterised by microangiopathy and fibrosis. Due to disease heterogeneity, in terms of extent, severity, and rate of progression, optimal therapeutic interventions are still lacking. Haematopoietic stem cells may be a new therapeutic option in this disease and, although the results of the first trials are encouraging, several issues remain to be addressed. On these bases, the stem cells transplantation is an area of active investigation, and an overview of the current available literature may help to define the role of this therapeutic strategy. Although the promising results, some unmet needs remain, including the transplantation protocols and their effects on immune system, the selection of the ideal patient and the pre-transplant cardiopulmonary evaluations. An improvement in these fields will allow us to optimize the haematopoietic stem cell therapies in SSc.

Extracellular Vesicles from Mesenchymal Stem Cells as Novel Treatments for Musculoskeletal Diseases

Mesenchymal stem/stromal cells (MSCs) represent a promising therapy for musculoskeletal diseases. There is compelling evidence indicating that MSC effects are mainly mediated by paracrine mechanisms and in particular by the secretion of extracellular vesicles (EVs). Many studies have thus suggested that EVs may be an alternative to cell therapy with MSCs in tissue repair. In this review, we summarize the current understanding of MSC EVs actions in preclinical studies of (1) immune regulation and rheumatoid arthritis, (2) bone repair and bone diseases, (3) cartilage repair and osteoarthritis, (4) intervertebral disk degeneration and (5) skeletal muscle and tendon repair. We also discuss the mechanisms underlying these actions and the perspectives of MSC EVs-based strategies for future treatments of musculoskeletal disorders.

Bone marrow mesenchymal stem cells in rheumatoid arthritis, spondyloarthritis, and ankylosing spondylitis: problems rather than solutions?

Background

Bone marrow mesenchymal stem cells (BM-MSCs) can dampen inflammation in animal models of inflammatory rheumatisms and human osteoarthritis. They are expected to be a solution for numerous human conditions. However, in rheumatoid arthritis (RA) and spondyloarthritis (SpA), subsets of subchondral BM-MSCs might conversely fuel synovitis and enthesitis.

Main text

Abnormal behaviour of BM-MSCs and/or their progeny has been found in RA and SpA. BM-MSCs also contribute to the ossifying processes observed in ankylosing spondylitis. Some synovial fibroblastic stem cells probably derive from BM-MSCs, but some stem cells can also migrate through the bare zone area of joints, not covered by cartilage, into the synovium. BM-MSCs can also migrate in the synovium over tendons. Sub-populations of bone marrow stem cells also invade the soft tissue side of enthesis via small holes in the bone cortex. The present review aims (1) to make a focus on these two aspects and (2) to put forward the hypothesis that lasting epigenetic changes of some BM-MSCs, induced by transient infections of the bone marrow close to the synovium and/or entheses (i.e. trained immunity of BM-MSCs and/or their progeny), contribute to the pathogenesis of inflammatory rheumatisms. Such hypothesis would fit with (1) the uneven distribution and/or flares of arthritis and enthesitis observed at the individual level in RA and SpA (reminiscent of what is observed following reactive arthritis and/or in Whipple’s disease); (2) the subchondral bone marrow oedema and erosions occurring in many RA patients, in the bare zone area; and (3) the frequent relapses of RA and SpA despite bone marrow transplantation, whereas most BM-MSCs resist graft preconditioning.

Conclusion

Some BM-MSCs might be more the problem than the solution in inflammatory rheumatisms. Subchondral bone marrow BM-MSCs and their progeny trafficking through the bare zone area of joints or holes in the bone cortex of entheses should be thoroughly studied in RA and SpA respectively. This may be done first in animal models. Mini-arthroscopy of joints could also be used in humans to specifically sample tissues close to the bare zone and/or enthesis areas.

Immunomodulatory effect of human bone marrow-derived mesenchymal stromal/stem cells on peripheral blood T cells from rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a Th1/Th17-mediated autoimmune disease whose current treatment, consisting in the blockage of inflammatory cytokines by disease-modifying antirheumatic drugs, is not effective for all patients. The therapeutic potential of mesenchymal stromal/stem cells' (MSCs) immunomodulatory properties is being explored in RA. Here, we investigate the effect of human bone marrow (BM)-MSCs on the expression of cytokines involved in RA physiopathology by the distinct functional compartments of CD4⁺ and CD8⁺ T cells from RA patients. Peripheral blood mononuclear cells from healthy individuals (n = 6) and RA patients (n = 12) were stimulated with phorbol myristate acetate plus ionomycin and cultured in the presence/absence of BM-MSCs. The expression of (interleukin) IL-2, tumor necrosis factor alpha (TNF-α), and interferon-gamma (IFN-γ) was evaluated in naive, central memory, effector memory, and effector CD4⁺ and CD8⁺ T cells, whereas IL-6, IL-9, and IL-17 expression was measured in total CD4⁺ and CD8⁺ T cells. mRNA expression of IL-4, IL-10, transforming growth factor beta (TGF-β), cytotoxic T-lymphocyte-associated antigen 4, and/or forkhead box P3 was quantified in fluorescence-activated cell sorting-purified CD4⁺ T cells, CD8⁺ T cells, and CD4⁺ Treg. BM-MSCs inhibited the production of TNF-α, IL-17, IL-6, IL-2, IFN-γ, and IL-9 by T cells from RA patients, mainly by reducing the percentage of cells producing cytokines. This inhibitory effect was transversal to all T cell subsets analyzed. At mRNA level, BM-MSCs increased expression of IL-10 and TGF-β by CD4⁺ and CD8⁺ T cells. BM-MSCs displayed a striking inhibitory action over T cells from RA patients, reducing the expression of cytokines involved in RA physiopathology. Remarkably, BM-MSC-derived immunomodulation affected either naive, effector, and memory T cells.

Issues and opportunities of stem cell therapy in autoimmune diseases

The purpose of regenerative medicine is to restore or enhance the normal function of human cells, tissues, and organs. From a clinical point of view, the use of stem cells is more advantageous than differentiated cells because they can be collected more easily and in larger quantities, their proliferation capacity is more pronounced, they are more resistant in cell culture, their aging is delayed, they are able to form a number of cell lines, and they are able to promote vascularization of tissue carriers. The therapeutic use of stem cells for disease modification, immunomodulation, or regenerative purposes are undoubtedly encouraging, but most studies are still in their early stages, and the clinical results reported are not clear with regard to therapeutic efficacy and potential side effects. Uniform regulation of the clinical application of stem cells is also indispensable for this highly customizable, minimally invasive, individualized therapeutic method to become a successful and safe treatment alternative in many different autoimmune and autoinflammatory disorders.

Mesenchymal Stem Cells Improve Rheumatoid Arthritis Progression by Controlling Memory T Cell Response

In the last years, mesenchymal stem cell (MSC)-based therapies have become an interesting therapeutic opportunity for the treatment of rheumatoid arthritis (RA) due to their capacity to potently modulate the immune response. RA is a chronic autoimmune inflammatory disorder with an incompletely understood etiology. However, it has been well described that peripheral tolerance defects and the subsequent abnormal infiltration and activation of diverse immune cells into the synovial membrane, are critical for RA development and progression. Moreover, the imbalance between the immune response of pro-inflammatory and anti-inflammatory cells, in particular between memory Th17 and memory regulatory T cells (Treg), respectively, is well admitted to be associated to RA immunopathogenesis. In this context, MSCs, which are able to alter the frequency and function of memory lymphocytes including Th17, follicular helper T (Tfh) cells and gamma delta (γδ) T cells while promoting Treg cell generation, have been proposed as a candidate of choice for RA cell therapy. Indeed, given the plasticity of memory CD4⁺ T cells, it is reasonable to think that MSCs will restore the balance between pro-inflammatory and anti-inflammatory memory T cells populations deregulated in RA leading to prompt their therapeutic function. In the present review, we will discuss the role of memory T cells implicated in RA pathogenesis and the beneficial effects exerted by MSCs on the phenotype and functions of these immune cells abnormally regulated in RA and how this regulation could impact RA progression.

Heme oxygenase-1 as a potential therapeutic target in rheumatic diseases

BACKGROUND

Heme oxygenase-1 (HO-1), a cellular stress protein, serves a vital metabolic function as the rate-limiting enzyme in the degradation of heme to generate carbon monoxide (CO), iron, and biliverdin (BR). HO-1 may function as one of the most momentous factors of cell adaptation to oxidase stress, as well as a regulator of inflammatory signaling programs through the generation of its biologically active end products. Intensive investigation is now focusing on the potential function of HO-1 in inflammatory disorders, among which rheumatic diseases are one of the principal issues.

METHODS

"Heme oxygenase-1", "rheumatic diseases"; "lupus", "rheumatic arthritis", "osteoarthritis" and "oxidative stress" were used as key words for searching in Pubmed and Google scholar database.

RESULTS

Collected information from the related articles revealed the important role of pathogenesis and therapeutic potential of HO-1 in rheumatic diseases. Conclusions and discussions HO-1 has potential as a target for the treatment of rheumatic diseases due to its characteristic anti-inflammatory and anti-oxidative role. However, it is essential to monitor the HO-1 expression during particular stage of the disorders, and levels of HO-1 in different tissues and organs should be further confirmed in order to correlate it with clinical symptoms and other hallmarks of rheumatic diseases.

Umbilical cord blood stem cell treatment for a patient with psoriatic arthritis

Clinical and laboratory results document psoriatic arthritis in a 56-year old patient. The symptoms did not resolve with standard treatments (nonsteroidal anti-inflammatory drugs, steroids and methotrexate). TNF-alpha inhibitors (certolizumab pegol and adalimumab) were added to the treatment regime, with some adverse effects. A trial of human umbilical cord stem cell therapy was then initiated. The stem cells were enriched and concentrated from whole cord blood, by removal of erythrocytes and centrifugation. The patient received several infusions of cord blood stem cells, through intravenous and intra-articular injections. These stem cell treatments correlated with remission of symptoms (joint pain and psoriatic plaques) and normalized serologic results for the inflammatory markers C-reactive protein and erythrocyte sedimentation rate. These improvements were noted within the first thirty days post-treatment, and were sustained for more than one year. The results of this trial suggest that cord blood stem cells may have important therapeutic value for patients with psoriatic arthritis, particularly for those who cannot tolerate standard treatments.