Manufacturing of human Wharton's jelly stem cells for clinical use: selection of serum is important

Comparing the growth kinetics and characteristics of Wharton's jelly derived mesenchymal stem cells expanded using different culture mediums

Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) can be isolated from umbilical cords which is abundant and easy to obtain. Due to their potent immunosuppressive properties, multilineage differentiation potential, and lack of ethical issues, WJ-MSCs are considered a promising candidate for therapeutic applications. However, large-scale in vitro expansion is necessary to obtain enough cells for therapeutic purposes. Therefore, this study aimed to optimize cell culture conditions and determine the characteristics of expanded WJ-MSCs. WJ-MSCs were seeded in 6-well plates at a density of 5000 cells/cm2 and cultured with different mediums, including DMEM-LG+10% FBS, DMEM-LG+10% HPL, serum-free commercial medium 1, serum-free GMP grade commercial medium 2, and HPL supplemented commercial medium 3. The cell morphology and growth kinetics were compared, and the three most suitable mediums were selected for further experiments. WJ-MSCs were then cultured in the selected mediums at seeding densities ranging from 1000 to 5000 cells/cm2, and cell growth kinetics were analysed. WJ-MSCs cultured in the selected mediums were characterized by their immunophenotype, tri-lineage differentiation potential and immunosuppression property. WJ-MSCs cultured with DMEM-LG+10% HPL, commercial medium 1 and commercial medium 2 showed smaller size, significantly higher cell yield, and shorter population doubling time than those cultured in other mediums. Hence, these three mediums were selected for further experiments. Only DMEM-LG + 10% HPL medium maintained high cell yields (1.48 ± 0.14 × 106 with bFGF and 1.56 ± 0.17 × 106 without bFGF) at the lowest seeding density tested. However, WJ-MSCs cultured in all three mediums expressed the MSC surface markers, were able to suppress PBMC proliferation, and could differentiate into adipogenic, chondrogenic and osteogenic lineages. In summary, DMEM-LG+10% HPL is the best medium for WJ-MSC expansion, as it provides the highest cell yield without compromising cell characteristics and functionality. The potential of this medium for large-scale expansion using a bioreactor or multilayered flask should be investigated in the future.

Ex vivo expansion in a clinical grade medium, containing growth factors from human platelets, enhances migration capacity of adipose stem cells

Introduction

Adipose tissue mesenchymal stem/stromal cells (ASC) can be used as advanced therapy medicinal product in regenerative and cancer medicine. We previously demonstrated Supernatant Rich in Growth Factors (SRGF) can replace fetal bovine serum (FBS) to expand ASC by a clinical grade compliant protocol. The therapeutic potential of ASC is based also on their homing capacity toward inflammatory/cancer sites: oriented cell migration is a fundamental process in this scenario. We investigated the impact of SRGF on ASC migration properties.

Methods

The motility/migration potential of ASC expanded in 5% SRGF was analyzed, in comparison to 10% FBS, by standard wound healing, bidimensional chemotaxis and transwell assays, and by millifluidic transwell tests. Mechanisms involved in the migration process were investigated by transient protein overexpression.

Results

In comparison to standard 10% FBS, supplementation of the cell culture medium with 5% SRGF, strongly increased migration properties of ASC along the chemotactic gradient and toward cancer cell derived soluble factors, both in static and millifluidic conditions. We showed that, independently from applied migratory stimulus, SRGF expanded ASC were characterized by far lower expression of α-smooth muscle actin (αSMA), a protein involved in the cell migration machinery. Overexpression of αSMA induced a significant and marked decrease in migration capacity of SRGF expanded ASC.

Discussion

In conclusion, 5% SRGF addition in the cell culture medium increases the migration potential of ASC, reasonably through appropriate downregulation of αSMA. Thus, SRGF could potentially improve the therapeutic impact of ASC, both as modulators of the immune microenviroment or as targeted drug delivery vehicles in oncology.

A GMP-compliant manufacturing method for Wharton's jelly-derived mesenchymal stromal cells

BACKGROUND

Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) hold great therapeutic potential in regenerative medicine. Therefore, it is crucial to establish a Good Manufacturing Practice (GMP)-compliant methodology for the isolation and culture of WJ-MSCs. Through comprehensive research, encompassing laboratory-scale experiments to pilot-scale studies, we aimed to develop standardized protocols ensuring the high yield and quality of WJ-MSCs manufacturing.

METHODS

Firstly, optimization of parameters for the enzymatic digestion method used to isolate WJ-MSCs was conducted. These parameters included enzyme concentrations, digestion times, seeding densities, and culture media. Additionally, a comparative analysis between the explant method and the enzymatic digestion method was performed. Subsequently, the consecutive passaging of WJ-MSCs, specifically up to passage 9, was evaluated using the optimized method. Finally, manufacturing processes were developed and scaled up, starting from laboratory-scale flask-based production and progressing to pilot-scale cell factory-based production. Furthermore, a stability study was carried out to assess the storage and use of drug products (DPs).

RESULTS

The optimal parameters for the enzymatic digestion method were a concentration of 0.4 PZ U/mL Collagenase NB6 and a digestion time of 3 h, resulting in a higher yield of P0 WJ-MSCs. In addition, a positive correlation between the weight of umbilical cord tissue and the quantities of P0 WJ-MSCs has been observed. Evaluation of different concentrations of human platelet lysate revealed that 2% and 5% concentrations resulted in similar levels of cell expansion. Comparative analysis revealed that the enzymatic digestion method exhibited faster outgrowth of WJ-MSCs compared to the explant method during the initial passage. Passages 2 to 5 exhibited higher viability and proliferation ability throughout consecutive passaging. Moreover, scalable manufacturing processes from the laboratory scale to the pilot scale were successfully developed, ensuring the production of high-quality WJ-MSCs. Multiple freeze-thaw cycles of the DPs led to reduced cell viability and viable cell concentration. Subsequent thawing and dilution of the DPs resulted in a significant decrease in both metrics, especially when stored at 20-27 °C.

CONCLUSION

This study offers valuable insights into optimizing the isolation and culture of WJ-MSCs. Our scalable manufacturing processes facilitate the large-scale production of high-quality WJ-MSCs. These findings contribute to the advancement of WJ-MSCs-based therapies in regenerative medicine.

The effect of Wharton's jelly-derived stem cells seeded/boron-loaded acellular scaffolds on the healing of full-thickness burn wounds in the rat model

Burn wounds are the most destructive and complicated type of skin or underlying soft tissue injury that are exacerbated by a prolonged inflammatory response. Several cell-based therapeutic systems through the culturing of potent stem cells on modified scaffolds have been developed to direct the burn healing challenges. In this context, a new regenerative platform based on boron (B) enriched-acellular sheep small intestine submucosa (AOSIS) scaffold was designed and used as a carrier for mesenchymal stem cells derived from Wharton's jelly (WJMSCs) aiming to promote the tissue healing in burn-induced rat models. hWJMSCs have been extracted from human extra-embryonic umbilical cord tissue. Thereafter, 96 third-degree burned Wistar male rats were divided into 4 groups. The animals that did not receive any treatment were considered as group A (control). Then, group B was treated just by AOSIS scaffold, group C was received cell-seeded AOSIS scaffold (hWJMSCs-AOSIS), and group D was covered by boron enriched-cell-AOSIS scaffold (B/hWJMSCs-AOSIS). Inflammatory factors, histopathological parameters, and the expression levels of epitheliogenic and angiogenic proteins were assessed on 5, 14 and 21 d post-wounding. Application of the B/hWJMSCs-AOSIS on full-thickness skin-burned wounds significantly reduced the volume of neutrophils and lymphocytes at day 21 post-burning, whilst the number of fibroblasts and blood vessels enhanced at this time. In addition, molecular and histological analysis of wounds over time further verified that the addition of boron promoted wound healing, with decreased inflammatory factors, stimulated vascularization, accelerated re-epithelialization, and enhanced expression levels of epitheliogenic genes. In addition, the boron incorporation amplified wound closure via increasing collagen deposition and fibroblast volume and activity. Therefore, this newly fabricated hWJMSCs/B-loaded scaffold can be used as a promising system to accelerate burn wound reconstruction through inflammatory regulation and angiogenesis stimulation.

A robust and standardized method to isolate and expand mesenchymal stromal cells from human umbilical cord

BACKGROUND AIMS

Human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs) are increasingly used in research and therapy. To obtain hUC-MSCs, a diversity of isolation and expansion methods are applied. Here, we report on a robust and standardized method for hUC-MSC isolation and expansion.

METHODS

Using 90 hUC donors, we compared and optimized critical variables during each phase of the multi-step procedure involving UC collection, processing, MSC isolation, expansion and characterization. Furthermore, we assessed the effect of donor-to-donor variability regarding UC morphology and donor attributes on hUC-MSC characteristics.

RESULTS

We demonstrated robustness of our method across 90 UC donors at each step of the procedure. With our method, UCs can be collected up to 6 h after birth, and UC-processing can be initiated up to 48 h after collection without impacting on hUC-MSC characteristics. The removal of blood vessels before explant cultures improved hUC-MSC purity. Expansion in Minimum essential medium α supplemented with human platelet lysate increased reproducibility of the expansion rate and MSC characteristics as compared with Dulbecco's Modified Eagle's Medium supplemented with fetal bovine serum. The isolated hUC-MSCs showed a purity of ∼98.9%, a viability of >97% and a high proliferative capacity. Trilineage differentiation capacity of hUC-MSCs was reduced as compared with bone marrow-derived MSCs. Functional assays indicated that the hUC-MSCs were able to inhibit T-cell proliferation demonstrating their immune-modulatory capacity.

CONCLUSIONS

We present a robust and standardized method to isolate and expand hUC-MSCs, minimizing technical variability and thereby lay a foundation to advance reliability and comparability of results obtained from different donors and different studies.

Mesenchymal stromal cells as a tool to unravel the developmental origins of disease

The intrauterine environment can induce alterations of the epigenome that have a lasting impact on disease risk. Current human studies in the field focus on a single epigenetic mark, DNA methylation, measured in blood. For in-depth mechanistic insight into the developmental origins of disease, it will be crucial to consider innovative tissue types. Mesenchymal stromal cells (MSCs) may serve as a novel tool to investigate the full epigenome beyond DNA methylation, to explore other omics levels, and to perform functional assays. Moreover, MSCs can be differentiated into multiple cell types and thereby mimic otherwise inaccessible cell types. A first wave of studies supports the potential of MSCs and illustrates how the innovative use of this cell type may be incorporated in birth cohorts.

Wharton's jelly-derived stromal cells and their cell therapy applications in allogeneic haematopoietic stem cell transplantation

For decades, mesenchymal stromal cells (MSCs) have been of great interest in the fields of regenerative medicine, tissue engineering and immunomodulation. Their tremendous potential makes it desirable to cryopreserve and bank MSCs to increase their accessibility and availability. Postnatally derived MSCs seem to be of particular interest because they are harvested after delivery without ethical controversy, they have the capacity to expand at a higher rate than adult‐derived MSCs, in which expansion decreases with ageing, and they have demonstrated immunological and haematological supportive properties similar to those of adult‐derived MSCs. In this review, we focus on MSCs obtained from Wharton's jelly (the mucous connective tissue of the umbilical cord between the amniotic epithelium and the umbilical vessels). Wharton's jelly MSCs (WJ‐MSCs) are a good candidate for cellular therapy in haematology, with accumulating data supporting their potential to sustain haematopoietic stem cell engraftment and to modulate alloreactivity such as Graft Versus Host Disease (GVHD). We first present an overview of their in‐vitro properties and the results of preclinical murine models confirming the suitability of WJ‐MSCs for cellular therapy in haematology. Next, we focus on clinical trials and discuss tolerance, efficacy and infusion protocols reported in haematology for GVHD and engraftment.

Quality by design to define critical process parameters for mesenchymal stem cell expansion

Stem cell-based therapeutic products could be the key to treat the deadliest current pathologies, ranging from neuro-degenerative to respiratory diseases. However, in order to bring these innovative therapeutics to a commercialization stage, reproducible manufacturing of high quality cell products is required. Although advances in cell culture techniques have led to more robust production processes and dramatically accelerated the development of early-phase clinical studies, challenges remain before regulatory approval, particularly to define and implement science-based quality standards (essential pre-requisites for national health agencies). In this regard, using new methodologies, such as Quality By Design (QBD), to build the production process around drug quality, could significantly reduce the chance of product rejection. This review-based work aims to perform a QBD approach to Mesenchymal Stem Cell (MSC) manufacturing in standard two-dimensional flasks, using published studies which have determined the impact of individual process parameters on defined Critical Quality Attributes (CQA). Along with this bibliographic analysis, parameter criticality was determined during the two main manufacturing stages (cell extraction and cell amplification) along with an overall classification in view of identifying the Critical Process Parameters (CPP). The analysis was performed in view of an improved standardization between research teams, and should contribute to reduce the gap towards compliant Good Manufacturing Practice (cGMP) manufacturing.

Allogeneic human umbilical cord Wharton's jelly stem cells increase several-fold the expansion of human cord blood CD34+ cells both in vitro and in vivo

Background

The transplantation of human umbilical cord blood (UCB) CD34+ cells has been successfully used to treat hematological disorders but one major limitation has been the low cell numbers available. Mesenchymal stem cells (MSCs) lying within the bone marrow in vivo behave like a scaffold on which CD34+ cells interact and proliferate. We therefore evaluated the use of allogeneic MSCs from the human UC Wharton’s jelly (hWJSCs) as stromal support for the ex vivo expansion of CD34+ cells.

Methods

We performed an in-depth evaluation of the primitiveness, migration, adhesion, maturation, mitochondrial behavior, and pathway mechanisms of this platform using conventional assays followed by the evaluation of engraftment potential of the expanded CD34+ cells in an in vivo murine model.

Results

We demonstrate that hWJSCs and its conditioned medium (hWJSC-CM) support the production of significantly high fold changes of CD34+, CD34+CD133+, CD34+CD90+, CD34+ALDH+, CD34+CD45+, and CD34+CD49f+ cells after 7 days of interaction when compared to controls. In the presence of hWJSCs or hWJSC-CM, the CD34+ cells produced significantly more primitive CFU-GEMM colonies, HoxB4, and HoxA9 gene expression and lower percentages of CD34+CXCR4+ cells. There were also significantly higher N-cadherin+ cell numbers and increased cell migration in transwell migration assays. The CD34+ cells expanded with hWJSCs had significantly lower mitochondrial mass, mitochondrial membrane potential, and oxidative stress. Green Mitotracker-tagged mitochondria from CD34+ cells were observed lying within red CellTracker-tagged hWJSCs under confocal microscopy indicating mitochondrial transfer via tunneling nanotubes. CD34+ cells expanded with hWJSCs and hWJSC-CM showed significantly reduced oxidative phosphorylation (ATP6VIH and NDUFA10) and increased glycolytic (HIF-1a and HK-1) pathway-related gene expression. CD34+ cells expanded with hWJSCs for 7 days showed significant greater CD45+ cell chimerism in the bone marrow of primary and secondary irradiated mice when transplanted intravenously.

Conclusions

In this report, we confirmed that allogeneic hWJSCs provide an attractive platform for the ex vivo expansion of high fold numbers of UCB CD34+ cells while keeping them primitive. Allogeneic hWJSCs are readily available in abundance from discarded UCs, can be easily frozen in cord blood banks, thawed, and then used as a platform for UCB-HSC expansion if numbers are inadequate.

Regulatory-compliant conditions during cell product manufacturing enhance in vitro immunomodulatory properties of infrapatellar fat pad-derived mesenchymal stem/stromal cells

BACKGROUND AIMS

Mesenchymal stem/stromal cell (MSC)-based therapies have gained attention as potential alternatives for multiple musculoskeletal indications based on their trophic and immunomodulatory properties. The infrapatellar fat pad (IFP) serves as a reservoir of MSCs, which play crucial roles modulating inflammatory and fibrotic events at the IFP and its neighboring tissue, the synovium. In an effort to comply with the existing regulatory framework regarding cell-based product manufacturing, we interrogated the in vitro immunomodulatory capacity of human-derived IFP-MSCs processed under different conditions, including a regulatory-compliant protocol, in addition to their response to the inflammatory and fibrotic environments often present in joint disease.

METHODS

Immunophenotype, telomere length, transcriptional and secretory immunomodulatory profiles and functional immunopotency assay were assessed in IFP-MSCs expanded in regular fetal bovine serum (FBS)-supplemented medium and side-by-side compared with same-donor cells processed with two media alternatives (i.e., regulatory-compliant pooled human platelet lysate [hPL] and a chemically reinforced/serum-reduced [Ch-R] formulation). Finally, to assess the effects of such formulations on the ability of the cells to respond to pro-inflammatory and pro-fibrotic conditions, all three groups were stimulated ex vivo (i.e., cell priming) with a cocktail containing TNFα, IFNγ and connective tissue growth factor (tumor-initiating cells) and compared with non-induced cohorts assessing the same outcomes.

RESULTS

Non-induced and primed IFP-MSCs expanded in either hPL or Ch-R showed distinct morphology in vitro, similar telomere dynamics and distinct phenotypical and molecular profiles when compared with cohorts grown in FBS. Gene expression of IL-8, CD10 and granulocyte colony-stimulating factor was highly enriched in similarly processed IFP-MSCs. Cell surface markers related to the immunomodulatory capacity, including CD146 and CD10, were highly expressed, and secretion of immunomodulatory and pro-angiogenic factors was significantly enhanced with both hPL and Ch-R formulations. Upon priming, the immunomodulatory phenotype was enhanced, resulting in further increase in CD146 and CD10, significant CXCR4 presence and reduction in TLR3. Similarly, transcriptional and secretory profiles were enriched and more pronounced in IFP-MSCs expanded in either hPL or Ch-R, suggesting a synergistic effect between these formulations and inflammatory/fibrotic priming conditions. Collectively, increased indoleamine-2,3-dioxygenase activity and prostaglandin E2 secretion for hPL- and Ch-R-expanded IFP-MSCs were functionally reflected by their robust T-cell proliferation suppression capacity in vitro compared with IFP-MSCs expanded in FBS, even after priming.

CONCLUSIONS

Compared with processing using an FBS-supplemented medium, processing IFP-MSCs with either hPL or Ch-R similarly enhances their immunomodulatory properties, which are further increased after exposure to an inflammatory/fibrotic priming environment. This evidence supports the adoption of regulatory-compliant practices during the manufacturing of a cell-based product based on IFP-MSCs and anticipates a further enhanced response once the cells face the pathological environment after intra-articular administration. Mechanistically, the resulting functionally enhanced cell-based product has potential utilization as a novel, minimally invasive cell therapy for joint disease through modulation of local immune and inflammatory events.

Serum-Free Medium Enhances the Therapeutic Effects of Umbilical Cord Mesenchymal Stromal Cells on a Murine Model for Acute Colitis

The usage of animal serum may ultimately prevent the application of ex vivo cultured mesenchymal stromal cells (MSCs) in a clinical setting due to safety concerns and batch-to-batch variability. Increasing regulatory pressure to limit use of animal serum has been issued and serum-free, xeno-free, and chemically defined media (S&XFM-CD) is encouraged to replace serum-containing media (SCM) in the stem cell preparation process. We previously developed a S&XFM-CD for the expansion of umbilical cord-derived MSCs (UCMSCs). Different culture conditions affect the function of MSCs, which may further affect the therapeutic efficiency and mechanisms of action. In this study, we compared the therapeutic effect and mechanism of UCMSCs in S&XFM-CD (UCMSC^S&XFM−CD) in experimental colitis with those in SCM (UCMSC^SCM). UCMSC^S&XFM−CD exhibited better therapeutic effects than UCMSC^SCM by body weight, disease activity index, and histological colitis score. UCMSC^S&XFM−CD or UCMSC^SCM migrated to the inflammation site of injured colon, but exhibited low levels of recruitment and persistence. Systemic depletion of endogenous macrophages impaired the therapeutic effects of UCMSC^SCM and UCMSC^S&XFM−CD. Furthermore, UCMSC^S&XFM−CD more markedly promoted intestinal macrophage polarisation from M1 to M2 phenotype to produce higher levels of IL-10 and lower levels of TNF-α in colon tissue than UCMSC^SCM, while a higher level of IL-4 was produced in UCMSC^SCM-treated group. UCMSC^S&XFM−CD cocultured with RAW264.7 cells in a transwell system promoted the release of TSG-6 and IL-6, whereas UCMSC^SCM increased PGE₂ levels. Taken together, we demonstrated that UCMSCs in S&XFM-CD exhibited improved therapeutic effects with altered cytokine secretion in an experimental acute colitis model.

Umbilical Cord MSCs and Their Secretome in the Therapy of Arthritic Diseases: A Research and Industrial Perspective

The prevalence of arthritic diseases is increasing in developed countries, but effective treatments are currently lacking. The injection of mesenchymal stem cells (MSCs) represents a promising approach to counteract the degenerative and inflammatory environment characterizing those pathologies, such as osteoarthritis (OA). However, the majority of clinical approaches based on MSCs are used within an autologous paradigm, with important limitations. For this reason, allogeneic MSCs isolated from cord blood (cbMSCs) and Wharton’s jelly (wjMSCs) gained increasing interest, demonstrating promising results in this field. Moreover, recent evidences shows that MSCs beneficial effects can be related to their secretome rather than to the presence of cells themselves. Among the trophic factors secreted by MSCs, extracellular vesicles (EVs) are emerging as a promising candidate for the treatment of arthritic joints. In the present review, the application of umbilical cord MSCs and their secretome as innovative therapeutic approaches in the treatment of arthritic joints will be examined. With the prospective of routine clinical applications, umbilical cord MSCs and EVs will be discussed also within an industrial and regulatory perspective.

Derivation of clinical-grade mesenchymal stromal cells from umbilical cord under chemically defined culture condition - platform for future clinical application

The use of animal serum in culture medium brings safety concerns and batch-to-batch variability, and thus may restrict the clinical use of ex vivo expanded mesenchymal stromal cells (MSCs). Clinically compliant MSCs should be developed in adherence to serum-free, xeno-free and chemically defined medium (S&XFM-CD). In this study, we develop a S&XFM-CD by replacing all serum components with synthetic alternatives for the derivation of clinical-grade umbilical cord-derived MSCs (UCMSCs). The critical aspects including characterization, safety concerns, potency and exogenous factors contamination risk of UCMSCs in S&XFM-CD are compared with serum-containing medium (SCM). UCMSCs in S&XFM-CD retain fibroblastic-like morphology and immunophenotype of MSCs, and exhibit superior clone efficiency, proliferation capacity, and osteogenic and chondrogenic differentiation potential compared with SCM. Moreover, UCMSCs in S&XFM-CD retain similar immunosuppressive potential, and exhibit superior secretion levels of bFGF, PDGF-BB and IGF-1 compared with SCM. In addition, UCMSCs in S&XFM-CD do not undergo transformation, preserve the normal karyotypes and genomic stability, and are less prone to senescence process after long-term in vitro culture, which conforms to the current guidance of international and national evaluation standard. The S&XFM-CD developed here may serve as a GMP-grade production platform of UCMSCs for future clinical application.

The effect of allogenic human Wharton's jelly stem cells seeded onto acellular dermal matrix in healing of rat burn wounds

BACKGROUND

Various methods were introduced to overcome the autograft shortage in burn wound care, including cell transplantation and tissue engineering.

AIMS

To evaluate the healing effect of allogenic human Wharton's jelly stem cells (hWJSCs) seeded onto acellular dermal matrix (ADM) in rat burn injuries.

PATIENTS AND METHODS

Human Wharton's jelly stem cells provided from umbilical cord tissue were characterized before transplantation, and the growth kinetic was determined. Skin samples from cosmetic surgeries were used for preparation of ADM. Forty male Sprague Dawley rats were randomly divided into 4 equal groups. Third-degree burn was induced for all animals by exposing to hot water using a 2 cm ring for 10 seconds. Group 1 was burned rats that did not receive any treatment. After burn injury, the second group received silver sulfadiazine (SSD), the third group was treated just by using ADM, and the fourth group received 2 × 10⁶ hWJSCs seeded onto ADM. The animals were euthanized for histologic evaluation after 7, 14, and 21 days.

RESULTS

Human Wharton's jelly stem cells were characterized to be spindle shape and positive for osteogenic and adipogenic induction and for mesenchymal markers but lacked hematopoietic markers. Population doubling time (PDT) was 40.1 hours with an increasing growth trend until day 6th. Macro- and microscopically, the healing was mild in ADM group and moderate in ADM + hWJSCs group after 21 days.

CONCLUSION

Allogenic hWJSCs seeded onto ADM improved the healing process in burn wounds denoting to their therapeutic and anti-inflammatory effects in burn wounds that can be added to the literature.

Insights into the Secretome of Mesenchymal Stem Cells and Its Potential Applications

Mesenchymal stem cells (MSCs) have regenerative, immunoregulatory properties and can be easily isolated and expanded in vitro. Despite being a powerful tool for clinical applications, they present limitations in terms of delivery, safety, and variability of therapeutic response. Interestingly, the MSC secretome composed by cytokines, chemokines, growth factors, proteins, and extracellular vesicles, could represent a valid alternative to their use. It is noteworthy that MSC-derived extracellular vesicles (MSC-EVs) have the same effect and could be advantageous compared to the parental cells because of their specific miRNAs load. MiRNAs could be useful both in diagnostic procedures such as “liquid biopsy” to identify early pathologies and in the therapeutic field. Not only are MSC-EVs’ preservation, transfer, and production easier, but their administration is also safer, hence some clinical trials are ongoing. However, much effort is required to improve the characterization of EVs to avoid artifacts and guarantee reproducibility of the studies.