Chromosomal characterization of cryopreserved mesenchymal stem cells from the human subendothelium umbilical cord vein

Controversies regarding transplantation of mesenchymal stem cells

Mesenchymal stem cells (MSCs) have tantalized regenerative medicine with their therapeutic potential, yet a cloud of controversies looms over their clinical transplantation. This comprehensive review navigates the intricate landscape of MSC controversies, drawing upon 15 years of clinical experience and research. We delve into the fundamental properties of MSCs, exploring their unique immunomodulatory capabilities and surface markers. The heart of our inquiry lies in the controversial applications of MSC transplantation, including the perennial debate between autologous and allogeneic sources, concerns about efficacy, and lingering safety apprehensions. Moreover, we unravel the enigmatic mechanisms surrounding MSC transplantation, such as homing, integration, and the delicate balance between differentiation and paracrine effects. We also assess the current status of clinical trials and the ever-evolving regulatory landscape. As we peer into the future, we examine emerging trends, envisioning personalized medicine and innovative delivery methods. Our review provides a balanced and informed perspective on the controversies, offering readers a clear understanding of the complexities, challenges, and potential solutions in MSC transplantation.

Long-Term Cryopreservation May Cause Genomic Instability and the Premature Senescence of Cells

Cryopreservation is an essential step for utilizing various cell types for biological research and medical purposes. At the same time, there is a lack of data on the effect of cryopreservation, especially when prolonged, on the karyotype of cells. In the present work, we analyzed the genetic stability of cells subjected to a cryopreservation procedure. The objects were immortalized Chinese hamster lung fibroblasts (CHL V-79 RJK line) and human endometrial mesenchymal stem/stromal cells (eMSCs). We showed that short-term cryopreservation in liquid nitrogen for up to 6 months did not affect the karyotype stability of CHL V-79 RJK and eMSCs. On the contrary, karyotyping of G-banded metaphase chromosomes in cells underwent 10-year cryopreservation, which revealed genomic instability in both cell lines associated with the variability of chromosome number in cells, random chromosomal rearrangements, and condensation disorder in homologs. In addition, we found out that long-term cryopreservation of eMSCs does not affect the expression of their typical surface markers and morphology, but results in a significant reduction in proliferative potential and early manifestation of cellular senescence features upon eMSCs culturing. Thus, we concluded that the long-term cryopreservation of cells of different types and biological origin can lead to irreversible changes of their karyotype and acceleration of cellular senescence.

Umbilical Cord Mesenchymal Stem Cell Therapy for Regenerative Treatment of Rheumatoid Arthritis: Opportunities and Challenges

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology with a high rate of disability. Traditional treatments for RA remain a challenging issue. For example, nonsteroidal anti-inflammatory drugs (NSAIDs) have no therapeutic effects on joint destruction, and the prominent side effects include gastrointestinal symptoms. RA is characterized by recurrence and bone attrition. Therefore, regenerative medicine and the use of umbilical cord mesenchymal stem cell (UC-MSC) therapies have recently emerged as potential options. UC-MSCs are multifunctional stem cells that are present in neonatal umbilical cord tissue and can differentiate into many kinds of cells, which have broad clinical application prospects in the tissue engineering of bone, cartilage, muscle, tendon, ligament, nerve, liver, endothelium, and myocardium. Moreover, UC-MSCs have advantages, such as convenient collection of materials and no ethical disputes; thus, these cells have attracted increasing attention from researchers. However, there are few clinical studies regarding UC-MSC therapy for RA. In this paper, we will review traditional drugs for RA treatment and then focus on UC-MSC therapy for RA, including preclinical and clinical UC-MSC applications for RA patients in the context of regenerative medicine. Finally, we will summarize the challenges and perspectives of UC-MSCs as a potential therapeutic strategy for RA. This review will help to design and discover more potent and efficacious treatments for RA patients and aid in advancing this class of cell therapy.

Research Progress of Mesenchymal Stem Cell Therapy for Severe COVID-19

Corona virus disease 2019 (COVID-19) refers to a type of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Sixty million confirmed cases have been reported worldwide until November 29, 2020. Unfortunately, the novel coronavirus is extremely contagious and the mortality rate of severe and critically ill patients is high. Thus, there is no definite and effective treatment in clinical practice except for antiviral therapy and supportive therapy. Mesenchymal stem cells (MSCs) are not only characterized by low immunogenicity and homing but also have anti-inflammatory and immunomodulation characteristics. Furthermore, they can inhibit the occurrence and development of a cytokine storm, inhibit lung injury, and exert antipulmonary fibrosis and antioxidative stress, therefore MSC therapy is expected to become one of the effective therapies to treat severe COVID-19. This article will review the possible mechanisms of MSCs in the treatment of severe COVID-19.

Principal Criteria for Evaluating the Quality, Safety and Efficacy of hMSC-Based Products in Clinical Practice: Current Approaches and Challenges

Human Mesenchymal Stem Cells (hMSCs) play an important role as new therapeutic alternatives in advanced therapies and regenerative medicine thanks to their regenerative and immunomodulatory properties, and ability to migrate to the exact area of injury. These properties have made hMSCs one of the more promising cellular active substances at present, particularly in terms of the development of new and innovative hMSC-based products. Currently, numerous clinical trials are being conducted to evaluate the therapeutic activity of hMSC-based products on specific targets. Given the rapidly growing number of hMSC clinical trials in recent years and the complexity of these products due to their cellular component characteristics and medicinal product status, there is a greater need to define more stringent, specific, and harmonized requirements to characterize the quality of the hMSCs and enhance the analysis of their safety and efficacy in final products to be administered to patients. These requirements should be implemented throughout the manufacturing process to guarantee the function and integrity of hMSCs and to ensure that the hMSC-based final product consistently meets its specifications across batches. This paper describes the principal phases involved in the design of the manufacturing process and updates the specific technical requirements needed to address the appropriate clinical use of hMSC-based products. The challenges and limitations to evaluating the safety, efficacy, and quality of hMSCs have been also reviewed and discussed.

Genetic Stability of Mesenchymal Stromal Cells for Regenerative Medicine Applications: A Fundamental Biosafety Aspect

Mesenchymal stem/stromal cells (MSC) show widespread application for a variety of clinical conditions; therefore, their use necessitates continuous monitoring of their safety. The risk assessment of mesenchymal stem cell-based therapies cannot be separated from an accurate and deep knowledge of their biological properties and in vitro and in vivo behavior. One of the most relevant safety issues is represented by the genetic stability of MSCs, that can be altered during in vitro manipulation, frequently required before clinical application. MSC genetic stability has the potential to influence the transformation and the therapeutic effect of these cells. At present, karyotype evaluation represents the definitely prevailing assessment of MSC stability, but DNA alterations of smaller size should not be underestimated. This review will focus on current scientific knowledge about the genetic stability of mesenchymal stem cells. The techniques used and possible improvements together with regulatory aspects will also be discussed.

Direct Reprogramming of Adult Human Somatic Stem Cells Into Functional Neurons Using Sox2, Ascl1, and Neurog2

Reprogramming of somatic cells into induced pluripotent stem cells (iPS) or directly into cells from a different lineage, including neurons, has revolutionized research in regenerative medicine in recent years. Mesenchymal stem cells are good candidates for lineage reprogramming and autologous transplantation, since they can be easily isolated from accessible sources in adult humans, such as bone marrow and dental tissues. Here, we demonstrate that expression of the transcription factors (TFs) SRY (sex determining region Y)-box 2 (Sox2), Mammalian achaete-scute homolog 1 (Ascl1), or Neurogenin 2 (Neurog2) is sufficient for reprogramming human umbilical cord mesenchymal stem cells (hUCMSC) into induced neurons (iNs). Furthermore, the combination of Sox2/Ascl1 or Sox2/Neurog2 is sufficient to reprogram up to 50% of transfected hUCMSCs into iNs showing electrical properties of mature neurons and establishing synaptic contacts with co-culture primary neurons. Finally, we show evidence supporting the notion that different combinations of TFs (Sox2/Ascl1 and Sox2/Neurog2) may induce multiple and overlapping neuronal phenotypes in lineage-reprogrammed iNs, suggesting that neuronal fate is determined by a combination of signals involving the TFs used for reprogramming but also the internal state of the converted cell. Altogether, the data presented here contribute to the advancement of techniques aiming at obtaining specific neuronal phenotypes from lineage-converted human somatic cells to treat neurological disorders.

Identification of new genes associated to senescent and tumorigenic phenotypes in mesenchymal stem cells

Although human mesenchymal stem cells (hMSCs) are a powerful tool for cell therapy, prolonged culture times result in replicative senescence or acquisition of tumorigenic features. To identify a molecular signature for senescence, we compared the transcriptome of senescent and young hMSCs with normal karyotype (hMSCs/n) and with a constitutional inversion of chromosome 3 (hMSC/inv). Senescent and young cells from both lineages showed differentially expressed genes (DEGs), with higher levels in senescent hMSCs/inv. Among the 30 DEGs in senescent hMSC/inv, 11 are new candidates for biomarkers of cellular senescence. The functional categories most represented in senescent hMSCs were related to cellular development, cell growth/proliferation, cell death, cell signaling/interaction, and cell movement. Mapping of DEGs onto biological networks revealed matrix metalloproteinase-1, thrombospondin 1, and epidermal growth factor acting as topological bottlenecks. In the comparison between senescent hMSCs/n and senescent hMSCs/inv, other functional annotations such as segregation of chromosomes, mitotic spindle formation, and mitosis and proliferation of tumor lines were most represented. We found that many genes categorized into functional annotations related to tumors in both comparisons, with relation to tumors being highest in senescent hMSCs/inv. The data presented here improves our understanding of the molecular mechanisms underlying the onset of cellular senescence as well as tumorigenesis.

Genetic evaluation of mesenchymal stem cells by G-banded karyotyping in a Cell Technology Center

Objective

To present the initial results of first three years of implementation of a genetic evaluation test for bone marrow-derived mesenchymal stem cells in a Cell Technology Center.

Methods

A retrospective study was carried out of 21 candidates for cell therapy. After the isolation of bone marrow mononuclear cells by density gradient, mesenchymal stem cells were cultivated and expanded at least until the second passage. Cytogenetic analyses were performed before and after cell expansion (62 samples) using G-banded karyotyping.

Results

All the samples analyzed, before and after cell expansion, had normal karyotypes, showing no clonal chromosomal changes. Signs of chromosomal instability were observed in 11 out of 21 patients (52%). From a total of 910 analyzed metaphases, five chromatid gaps, six chromatid breaks and 14 tetraploid cells were detected giving as total of 25 metaphases with chromosome damage (2.75%).

Conclusion

The absence of clonal chromosomal aberrations in our results for G-banded karyotyping shows the maintenance of chromosomal stability of bone marrow-derived mesenchymal stem cells until the second passage; however, signs of chromosomal instability such as chromatid gaps, chromosome breaks and tetraploidy indicate that the long-term cultivation of these cells can provide an intermediate step for tumorigenesis.

Cytokinesis-block micronucleus assay adapted for analyzing genomic instability of human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) are multipotent cells used in cell therapy research. One of the problems involving hMSCs is the possibility of genetic instability during in vitro expansion required to obtain a suitable number of cells for clinical applications. The cytokinesis-block micronucleus (CBMN) assay measures genetic instability by analyzing the presence of micronucleus (MN), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs) in binucleated cells. The present study describes modifications in the CBMN assay methodology to analyze genetic instability in hMSCs isolated from the umbilical vein and in vitro expanded. The best protocol to achieve binucleated hMSCs with preserved cytoplasm was as follows: cytochalasin B concentration (4.0 μg/mL), use of hypotonic treatment (3 min), and the fixative solution (9 methanol:1 acetic acid). These adaptations were reproduced in three hMSC primary cell cultures and also in XP4PA and A549 cell lines. The frequency of hMSCs treated with mitomycin-C presenting MN was lower than that with other nuclear alterations, indicating that the hMSCs contain mechanisms to avoid a high level of chromosomal breaks. However, a high frequency of cells with NPBs was detected and spontaneous anaphase bridges under normal hMSC in vitro culture were observed. Considering that anaphase bridges are characteristic alterations in tumor cells, the CBMN assay is indicated as an important tool associated with other genetic analyses in order to ensure the safe clinical use of hMSCs in cell therapy.

Human adipose stromal cells (ASC) for the regeneration of injured cartilage display genetic stability after in vitro culture expansion

Mesenchymal stromal cells are emerging as an extremely promising therapeutic agent for tissue regeneration due to their multi-potency, immune-modulation and secretome activities, but safety remains one of the main concerns, particularly when in vitro manipulation, such as cell expansion, is performed before clinical application. Indeed, it is well documented that in vitro expansion reduces replicative potential and some multi-potency and promotes cell senescence. Furthermore, during in vitro aging there is a decrease in DNA synthesis and repair efficiency thus leading to DNA damage accumulation and possibly inducing genomic instability. The European Research Project ADIPOA aims at validating an innovative cell-based therapy where autologous adipose stromal cells (ASCs) are injected in the diseased articulation to activate regeneration of the cartilage. The primary objective of this paper was to assess the safety of cultured ASCs. The maintenance of genetic integrity was evaluated during in vitro culture by karyotype and microsatellite instability analysis. In addition, RT-PCR array-based evaluation of the expression of genes related to DNA damage signaling pathways was performed. Finally, the senescence and replicative potential of cultured cells was evaluated by telomere length and telomerase activity assessment, whereas anchorage-independent clone development was tested in vitro by soft agar growth. We found that cultured ASCs do not show genetic alterations and replicative senescence during the period of observation, nor anchorage-independent growth, supporting an argument for the safety of ASCs for clinical use.