Ex Vivo Expanded Mesenchymal Stromal Cell Minimal Quality Requirements for Clinical Application

Emerging Strategies in Mesenchymal Stem Cell-Based Cardiovascular Therapeutics

Cardiovascular diseases continue to challenge global health, demanding innovative therapeutic solutions. This review delves into the transformative role of mesenchymal stem cells (MSCs) in advancing cardiovascular therapeutics. Beginning with a historical perspective, we trace the development of stem cell research related to cardiovascular diseases, highlighting foundational therapeutic approaches and the evolution of cell-based treatments. Recognizing the inherent challenges of MSC-based cardiovascular therapeutics, which range from understanding the pro-reparative activity of MSCs to tailoring patient-specific treatments, we emphasize the need to refine the pro-regenerative capacity of these cells. Crucially, our focus then shifts to the strategies of the fourth generation of cell-based therapies: leveraging the secretomic prowess of MSCs, particularly the role of extracellular vesicles; integrating biocompatible scaffolds and artificial sheets to amplify MSCs' potential; adopting three-dimensional ex vivo propagation tailored to specific tissue niches; harnessing the promise of genetic modifications for targeted tissue repair; and institutionalizing good manufacturing practice protocols to ensure therapeutic safety and efficacy. We conclude with reflections on these advancements, envisaging a future landscape redefined by MSCs in cardiovascular regeneration. This review offers both a consolidation of our current understanding and a view toward imminent therapeutic horizons.

Mesenchymal stem cell secretome and extracellular vesicles for neurodegenerative diseases: Risk-benefit profile and next steps for the market access

Neurodegenerative diseases represent a growing burden on healthcare systems worldwide. Mesenchymal stem cells (MSCs) have shown promise as a potential therapy due to their neuroregenerative, neuroprotective, and immunomodulatory properties, which are, however, linked to the bioactive substances they release, collectively known as secretome. This paper provides an overview of the most recent research on the safety and efficacy of MSC-derived secretome and extracellular vesicles (EVs) in clinical (if available) and preclinical models of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, Huntington's disease, acute ischemic stroke, and spinal cord injury. The article explores the biologically active substances within MSC-secretome/EVs, the mechanisms responsible for the observed therapeutic effects, and the strategies that may be used to optimize MSC-secretome/EVs production based on specific therapeutic needs. The review concludes with a critical discussion of current clinical trials and a perspective on potential future directions in translating MSC-secretome and EVs into the clinic, specifically regarding how to address the challenges associated with their pharmaceutical manufacturing, including scalability, batch-to-batch consistency, adherence to Good Manufacturing Practices (GMP) guidelines, formulation, and storage, along with quality controls, access to the market and relative costs, value for money and impact on total expenditure.

Spermidine Retarded the Senescence of Multipotent Mesenchymal Stromal Cells In Vitro and In Vivo through SIRT3-Mediated Antioxidation

Multipotent mesenchymal stromal cells (MSCs) expand in vitro and undergo replicative senescence, thereby restricting their clinical utilization. Thus, an effective strategy is required to impede MSC senescence. Since spermidine (SPD) supplementation can prolong the lifespan of yeast by inhibiting oxidative stress, spermidine is a potential option for delaying MSC senescence. In this study, to test our hypothesis, we first isolated primary human umbilical cord mesenchymal stem cells (hUCMSCs). Subsequently, the appropriate SPD dose was administered during continuous cell cultivation. Next, we evaluated the antisenescence effects by SA-β-gal staining, Ki67 expression, reactive oxygen species (ROS) levels, adipogenic or osteogenic ability, senescence-associated markers, and DNA damage markers. The results revealed that early SPD intervention significantly delays the replicative senescence of hUCMSCs and constrains premature H₂O₂-induced senescence. Additionally, by silencing SIRT3, the SPD-mediated antisenescence effects disappear, further demonstrating that SIRT3 is necessary for SPD to exert its antisenescence effects on hUCMSCs. Besides, the findings of this study also suggest that SPD in vivo protects MSCs against oxidative stress and delays cell senescence. Thus, MSCs maintain the ability to proliferate and differentiate efficiently in vitro and in vivo, which reflects the potential clinical utilization of MSCs in the future.

Potency Assays: The 'Bugaboo' of Stem Cell Therapy

Substantially manipulated cell-based products for human use are considered medicines and therefore regulatory authorities require extensive characterisation in terms of identity, purity and potency. The latter critical quality attribute is probably the most challenging to identify and measure, requiring provision that potency assays should reflect the intended mechanism of action and demonstrate the drugs' biological effect. However, in most cases, the mechanisms involved are not fully understood, making the definition and validation of suitable potency tests difficult, a 'bugaboo' quest to be feared. Although it is evident that much work is still needed in the scientific arena, the present chapter focuses on strategies currently used by developers of cell- and gene-based therapies to demonstrate potency of innovative medicines, the regulatory framework and need for standardisation seeking to demystify critical factors to consider when designing a potency assay.

Stem Cells in Regenerative Medicine

Stem cells constitute a set of undifferentiated cells with the capacity to differentiate into other cell types and to self-renew [...].

A New Human Platelet Lysate for Mesenchymal Stem Cell Production Compliant with Good Manufacturing Practice Conditions Preserves the Chemical Characteristics and Biological Activity of Lyo-Secretome Isolated by Ultrafiltration

Recently, we proposed a Good Manufacturing Practice (GMP)-compliant production process for freeze-dried mesenchymal stem cell (MSC)-secretome (lyo-secretome): after serum starvation, the cell supernatant was collected, and the secretome was concentrated by ultrafiltration and freeze-dried, obtaining a standardized ready-to-use and stable powder. In this work, we modified the type of human platelet lysate (HPL) used as an MSC culture supplement during the lyo-secretome production process: the aim was to verify whether this change had an impact on product quality and also whether this new procedure could be validated according to GMP, proving the process robustness. MSCs were cultured with two HPLs: the standard previously validated one (HPL-E) and the new one (HPL-S). From the same pool of platelets, two batches of HPL were obtained: HPL-E (by repeated freezing and thawing cycles) and HPL-S (by adding Ca-gluconate to form a clot and its subsequent mechanical wringing). Bone marrow MSCs from three donors were separately cultured with the two HPLs until the third passage and then employed to produce lyo-secretome. The following indicators were selected to evaluate the process performance: (i) the lyo-secretome quantitative composition (in lipids and proteins), (ii) the EVs size distribution, and (iii) anti-elastase and (iv) immunomodulant activity as potency tests. The new HPL supplementation for MSCs culture induced only a few minimal changes in protein/lipid content and EVs size distribution; despite this, it did not significantly influence biological activity. The donor intrinsic MSCs variability in secretome secretion instead strongly affected the quality of the finished product and could be mitigated by concentrating the final product to reach a determined protein (and lipid) concentration. In conclusion, the modification of the type of HPL in the MSCs culture during lyo-secretome production induces only minimal changes in the composition but not in the potency, and therefore, the new procedure can be validated according to GMP.

A New Human Platelet Lysate for Mesenchymal Stem Cell Production Compliant with Good Manufacturing Practice Conditions

Mesenchymal stem cells (MSCs) are classified as advanced therapy medicinal products, a new category of GMP (good manufacturing practice)-compliant medicines for clinical use. We isolated MSCs from 5 bone marrow (BM) samples using human platelet lysate (HPL) instead of foetal bovine serum (FBS). We used a new method of HPL production consisting of treating platelet (PLTs) pools with Ca-Gluconate to form a gel clot, then mechanically squeezing to release growth factors. We compared the new HPL (HPL-S) with the standard (HPL-E) obtained by freezing/thawing cycles and by adding heparin. HPL-S had not PLTs and fibrinogen but the quantity of proteins and growth factors was comparable to HPL-E. Therefore, HPL-S needed fewer production steps to be in compliance with GMP conditions. The number of colonies forming unit-fibroblasts (CFU-F) and the maintenance of stem markers showed no significant differences between MSCs with HPL-E and HPL-S. The cumulative population doubling was higher in MSCs with HPL-E in the earlier passages, but we observed an inverted trend of cell growth at the fourth passage. Immunophenotypic analysis showed a significant lower expression of HLA-DR in the MSCs with HPL-S (1.30%) than HPL-E (14.10%). In conclusion, we demonstrated that HPL-S is an effective alternative for MSC production under GMP conditions.

Interleukin-10 genetically modified clinical-grade mesenchymal stromal cells markedly reinforced functional recovery after spinal cord injury via directing alternative activation of macrophages

Background

After spinal cord injury (SCI), dysregulated or nonresolving inflammatory processes can severely disturb neuronal homeostasis and drive neurodegeneration. Although mesenchymal stromal cell (MSC)-based therapies have showed certain therapeutic efficacy, no MSC therapy has reached its full clinical goal. In this study, we examine interleukin-10 (IL10) genetically modified clinical-grade MSCs (IL10-MSCs) and evaluate their clinical safety, effectiveness, and therapeutic mechanism in a completely transected SCI mouse model.

Methods

We established stable IL10-overexpressing human umbilical-cord-derived MSCs through electric transduction and screened out clinical-grade IL10-MSCs according to the criteria of cell-based therapeutic products, which were applied to mice with completely transected SCI by repeated tail intravenous injections. Then we comprehensively investigated the motor function, histological structure, and nerve regeneration in SCI mice, and further explored the potential therapeutic mechanism after IL10-MSC treatment.

Results

IL10-MSC treatment markedly reinforced locomotor improvement, accompanied with decreased lesion volume, regeneration of axons, and preservation of neurons, compared with naïve unmodified MSCs. Further, IL10-MSC transplantation increased the ratio of microglia to infiltrated alternatively activated macrophages (M2), and reduced the ratio of classically activated macrophages (M1) at the injured spinal cord, meanwhile increasing the percentage of Treg and Th2 cells, and reducing the percentage of Th1 cells in the peripheral circulatory system. In addition, IL10-MSC administration could prevent apoptosis and promote neuron differentiation of neural stem cells (NSCs) under inflammatory conditions in vitro.

Conclusions

IL10-MSCs exhibited a reliable safety profile and demonstrated promising therapeutic efficacy in SCI compared with naïve MSCs, providing solid support for future clinical application of genetically engineered MSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00325-9.

A Novel Xeno-Free Method to Isolate Human Endometrial Mesenchymal Stromal Cells (E-MSCs) in Good Manufacturing Practice (GMP) Conditions

The cyclic regeneration of human endometrium is guaranteed by the proliferative capacity of endometrial mesenchymal stromal cells (E-MSCs). Due to this, the autologous infusion of E-MSCs has been proposed to support endometrial growth in a wide range of gynecological diseases. We aimed to compare two different endometrial sampling methods, surgical curettage and vacuum aspiration biopsy random assay (VABRA), and to validate a novel xeno-free method to culture human E-MSCs. Six E-MSCs cell samples were isolated after mechanical tissue homogenization and cultured using human platelet lysate. E-MSCs were characterized for the colony formation capacity, proliferative potential, and multilineage differentiation. The expression of mesenchymal and stemness markers were tested by FACS analysis and real-time PCR, respectively. Chromosomal alterations were evaluated by karyotype analysis, whereas tumorigenic capacity and invasiveness were tested by soft agar assay. Both endometrial sampling techniques allowed efficient isolation and expansion of E-MSCs using a xeno-free method, preserving their mesenchymal and stemness phenotype, proliferative potential, and limited multi-lineage differentiation ability during the culture. No chromosomal alterations and invasive/tumorigenic capacity were observed. Herein, we report the first evidence of efficient E-MSCs isolation and culture in Good Manufacturing Practice compliance conditions, suggesting VABRA endometrial sampling as alternative to surgical curettage.

Therapeutic Mesenchymal Stem/Stromal Cells: Value, Challenges and Optimization

Cellular therapy aims to replace damaged resident cells by restoring cellular and molecular environments suitable for tissue repair and regeneration. Among several candidates, mesenchymal stem/stromal cells (MSCs) represent a critical component of stromal niches known to be involved in tissue homeostasis. In vitro, MSCs appear as fibroblast-like plastic adherent cells regardless of the tissue source. The therapeutic value of MSCs is being explored in several conditions, including immunological, inflammatory and degenerative diseases, as well as cancer. An improved understanding of their origin and function would facilitate their clinical use. The stemness of MSCs is still debated and requires further study. Several terms have been used to designate MSCs, although consensual nomenclature has yet to be determined. The presence of distinct markers may facilitate the identification and isolation of specific subpopulations of MSCs. Regarding their therapeutic properties, the mechanisms underlying their immune and trophic effects imply the secretion of various mediators rather than direct cellular contact. These mediators can be packaged in extracellular vesicles, thus paving the way to exploit therapeutic cell-free products derived from MSCs. Of importance, the function of MSCs and their secretome are significantly sensitive to their environment. Several features, such as culture conditions, delivery method, therapeutic dose and the immunobiology of MSCs, may influence their clinical outcomes. In this review, we will summarize recent findings related to MSC properties. We will also discuss the main preclinical and clinical challenges that may influence the therapeutic value of MSCs and discuss some optimization strategies.

A practical approach for gmp-compliant validation of real-time PCR method for mycoplasma detection in human mesenchymal stromal cells as advanced therapy medicinal product

BACKGROUND

Manufacturing of human Mesenchymal Stromal Cells as advanced therapy medicinal product (ATMP) for clinical use involves an ex vivo expansion, which leads to a risk of contamination by microbiological agents. Even if manufacturing under Good Manufacturing Practice (GMP) license minimizes this risk, contamination of cell cultures by mycoplasmas still represents a widespread problem. Furthermore, the absence of mycoplasma contamination represents one of ATMPs release criteria. Since July 2007, European Pharmacopoeia (EuPh) offers the possibility to replace official mycoplasma detection methods with Nucleic Acid Amplification techniques, after suitable validation. As an Italian authorized Cell Factory, we developed an in-house GMP-compliant validation of real-time PCR method for mycoplasma detection in human Mesenchymal Stromal Cells, according to EuPh sec. 2.6.7 and International Conference on Harmonization Q₂.

MATERIALS AND METHODS

The study was performed in compliance with GMP international requirements with MycoSEQ™ Mycoplasma Detection Assay (Thermofisher) on QuantStudio5 real-Time PCR (Applied Biosystems). Assay validation was developed to evaluate sensitivity, interferences matrix-related, specificity and robustness.

RESULTS

MycoSEQ™ Mycoplasma Detection Assay has been successfully validated on human Mesenchymal Stromal Cells as results comply with validation protocol acceptance criteria.

CONCLUSIONS

MycoSEQ™ Mycoplasma Detection Assay is a fast, sensitive and specific PCR-based Nucleic Acid Test assay that can be used as an alternative to official mycoplasma test methods for lot release of human Mesenchymal Stromal Cells as advanced therapy medicinal product (ATMP). Moreover, our study underlines the presence of interference on real-time PCR reaction due to matrix composition, pointing out a practical approach for method validation (i.e interference removal).

The potential role of mesenchymal stem cells in modulating antiageing process

Ageing and age-related diseases share some basic origin that largely converges on inflammation. Precisely, it boils down to a common pathway characterised by the appearance of a fair amount of proinflammatory cytokines known as inflammageing. Among the proposed treatment for antiageing, MSCs gained attention in recent years. Since mesenchymal stem cells (MSCs) can differentiate itself into a myriad of terminal cells, previously it was believed that these cells migrate to the site of injury and perform their therapeutic effect. However, with the more recent discovery of huge amounts of paracrine factors secreted by MSCs, it is now widely accepted that these cells do not engraft upon transplantation but rather unveil their benefits through excretion of bioactive molecules namely those involved in inflammatory and immunomodulatory activities. Conversely, the true function of these paracrine changes has not been thoroughly investigated all these years. Hence, this review will describe in detail on ways MSCs may capitalize its paracrine properties in modulating antiageing process. Through a comprehensive literature search various elements in the antiageing process, we aim to provide a novel treatment perspective of MSCs in antiageing related clinical conditions.

Regenerative medicine for neurological diseases-will regenerative neurosurgery deliver?

Regenerative medicine aspires to transform the future practice of medicine by providing curative, rather than palliative, treatments. Healing the central nervous system (CNS) remains among regenerative medicine's most highly prized but formidable challenges. "Regenerative neurosurgery" provides access to the CNS or its surrounding structures to preserve or restore neurological function. Pioneering efforts over the past three decades have introduced cells, neurotrophins, and genes with putative regenerative capacity into the CNS to combat neurodegenerative, ischemic, and traumatic diseases. In this review we critically evaluate the rationale, paradigms, and translational progress of regenerative neurosurgery, harnessing access to the CNS to protect, rejuvenate, or replace cell types otherwise irreversibly compromised by neurological disease. We discuss the evidence surrounding fetal, somatic, and pluripotent stem cell derived implants to replace endogenous neuronal and glial cell types and provide trophic support. Neurotrophin based strategies via infusions and gene therapy highlight the motivation to preserve neuronal circuits, the complex fidelity of which cannot be readily recreated. We specifically highlight ongoing translational efforts in Parkinson's disease, amyotrophic lateral sclerosis, stroke, and spinal cord injury, using these to illustrate the principles, challenges, and opportunities of regenerative neurosurgery. Risks of associated procedures and novel neurosurgical trials are discussed, together with the ethical challenges they pose. After decades of efforts to develop and refine necessary tools and methodologies, regenerative neurosurgery is well positioned to advance treatments for refractory neurological diseases. Strategic multidisciplinary efforts will be critical to harness complementary technologies and maximize mechanistic feedback, accelerating iterative progress toward cures for neurological diseases.

A Step Toward Optimizing Regenerative Medicine Principle to Combat COVID-19

Drugs are currently not licensed in specific to pulverize COVID-19. On an emergency basis, vaccines were approved to prevent the further spread of COVID-19. This serves as a potential background for considering the optimization of biologics. In this context, evidence on convalescent plasma and stem cells has shown a beneficial role. Here, we have considered this as plausible therapy, and further hypothesize that their cocktails will synergistically boost the immunogenicity to relegate COVID-19. This warrants a large volume clinical trial on an emergent basis, because the sooner we establish a safe and effective cure, the better.

MSC Manufacturing for Academic Clinical Trials: From a Clinical-Grade to a Full GMP-Compliant Process

Following European regulation 1394/2007, mesenchymal stromal cell (MSCs) have become an advanced therapy medicinal product (ATMP) that must be produced following the good manufacturing practice (GMP) standards. We describe the upgrade of our existing clinical-grade MSC manufacturing process to obtain GMP certification. Staff organization, premises/equipment qualification and monitoring, raw materials management, starting materials, technical manufacturing processes, quality controls, and the release, thawing and infusion were substantially reorganized. Numerous studies have been carried out to validate cultures and demonstrate the short-term stability of fresh or thawed products, as well their stability during long-term storage. Detailed results of media simulation tests, validation runs and early MSC batches are presented. We also report the validation of a new variant of the process aiming to prepare fresh MSCs for the treatment of specific lesions of Crohn's disease by local injection. In conclusion, we have successfully ensured the adaptation of our clinical-grade MSC production process to the GMP requirements. The GMP manufacturing of MSC products is feasible in the academic setting for a limited number of batches with a significant cost increase, but moving to large-scale production necessary for phase III trials would require the involvement of industrial partners.

Current good manufacturing practice considerations for mesenchymal stromal cells as therapeutic agents

Producing human mesenchymal stromal cells (MSCs) for clinical use requires adherence to current good manufacturing practice (cGMP) standards. This is necessary for ensuring standardization and reproducibility through the manufacturing process, but also, for product quality and safety. However, the large-scale production of clinical-grade MSCs possesses unique regulatory challenges and hurdles related to the heterogeneous nature of MSC cultures as well as the complex manufacturing process. Following is a compilation of the major issues encountered in the manufacturing of MSCs for clinical use, and our views on the optimal characteristics of the final MSC product.

Therapeutic Applications of Mesenchymal Stem Cells in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is an interstitial disease of unknown etiology characterized by progressive pulmonary fibrosis. Pirfenidone and nintedanib are the only drugs that can prolong the time to disease progression, slow down the decline in lung function, and prolong survival. However, they do not offer a cure and are associated with tolerability issues. The pluripotency of mesenchymal stem cells (MSCs) and their ability to regulate immunity, inhibit inflammation, and promote epithelial tissue repair highlight the promise of MSC therapy for treating interstitial lung disease. However, optimal protocols are lacking for multi-parameter selection in MSC therapy. This review summarizes preclinical studies on MSC transplantation for the treatment of interstitial lung disease and clinical studies with known results. An analysis of relevant factors for the optimization of treatment plans is presented, including MSCs with different sources, administration routes and timing, dosages, frequencies, and pretreatments with MSCs. This review proposes an optimized plan for guiding the design of future clinical research to identify therapeutic options for this complex disease.

Fostering mesenchymal stem cell therapy to halt cytokine storm in COVID-19

The coronavirus disease 2019 (COVID-19) has been threatening the globe since the end of November 2019. The disease revealed cracks in the health care system as health care providers across the world were left without guidelines on definitive usage of pharmaceutical agents or vaccines. The World Health Organization (WHO) declared COVID-19 as a pandemic on the 11th of March 2020. Individuals with underlying systemic disorders have reported complications, such as cytokine storms, when infected with the virus. As the number of positive cases and the death toll across the globe continue to rise, various researchers have turned to cell based therapy using stem cells to combat COVID-19. The field of stem cells and regenerative medicine has provided a paradigm shift in treating a disease with minimally invasive techniques that provides maximal clinical and functional outcome for patients. With the available evidence of immunomodulatory and immune-privilege actions, mesenchymal stem cells (MSCs) can repair, regenerate and remodulate the native homeostasis of pulmonary parenchyma with improved pulmonary compliance. This article revolves around the usage of novel MSCs therapy for combating COVID-19.

Ex vivo-expanded highly pure ABCB5+ mesenchymal stromal cells as Good Manufacturing Practice-compliant autologous advanced therapy medicinal product for clinical use: process validation and first in-human data

Background aim:

Mesenchymal stromal cells (MSCs) hold promise for the treatment of tissue damage and injury. However, MSCs comprise multiple subpopulations with diverse properties, which could explain inconsistent therapeutic outcomes seen among therapeutic attempts. Recently, the adenosine triphosphate-binding cassette transporter ABCB5 has been shown to identify a novel dermal immunomodulatory MSC subpopulation.

Methods:

The authors have established a validated Good Manufacturing Practice (GMP)-compliant expansion and manufacturing process by which ABCB5⁺ MSCs can be isolated from skin tissue and processed to generate a highly functional homogeneous cell population manufactured as an advanced therapy medicinal product (ATMP). This product has been approved by the German competent regulatory authority to be tested in a clinical trial to treat therapy-resistant chronic venous ulcers.

Results:

As of now, 12 wounds in nine patients have been treated with 5 × 10⁵ autologous ABCB5⁺ MSCs per cm² wound area, eliciting a median wound size reduction of 63% (range, 32–100%) at 12 weeks and early relief of pain.

Conclusions:

The authors describe here their GMP- and European Pharmacopoeia-compliant production and quality control process, report on a pre-clinical dose selection study and present the first in-human results. Together, these data substantiate the idea that ABCB5⁺ MSCs manufactured as ATMPs could deliver a clinically relevant wound closure strategy for patients with chronic therapy-resistant wounds.

GMP-compliant sponge-like dressing containing MSC lyo-secretome: Proteomic network of healing in a murine wound model

Chronic wounds account for 3% of total healthcare expenditure of developed countries; thus, innovative therapies, including Mesenchymal Stem Cells (MSCs) end their exosomes are increasingly considered, even if the activity depends on the whole secretome, made of both soluble proteins and extracellular vesicles. In this work, we prove for the first time the in vivo activity of the whole secretome formulated in a sponge-like alginate wound dressing to obtain the controlled release of bioactive substances. The product has been prepared in a public GMP-compliant facility by a scalable process; based on the murine model, treated wounds healed faster than controls without complications or infections. The treatment induced a higher acute inflammatory process in a short time and sustained the proliferative phase by accelerating fibroblast migration, granulation tissue formation, neovascularization and collagen deposition. The efficacy was substantially supported by the agreement between histological and proteomic findings. In addition to functional modules related to proteolysis, complement and coagulation cascades, protein folding and ECM remodeling, in treated skin, emerged the role of specific wound healing related proteins, including Tenascin (Tnc), Decorin (Dcn) and Epidermal growth factor receptor (EGFR). Of note, Decorin and Tenascin were also components of secretome, and network analysis suggests a potential role in regulating EGFR. Although further experiments will be necessary to characterize better the molecular keys induced by treatment, overall, our results confirm the whole secretome efficacy as novel "cell-free therapy". Also, sponge-like topical dressing containing the whole secretome, GMP- compliant and "ready-off-the-shelf", may represent a relevant point to facilitate its translation into the clinic.

Reducing mortality and morbidity in patients with severe COVID-19 disease by advancing ongoing trials of Mesenchymal Stromal (stem) Cell (MSC) therapy - Achieving global consensus and visibility for cellular host-directed therapies

As of May 17th 2020, the novel coronavirus disease 2019 (COVID-19) pandemic has caused 307,395 deaths worldwide, out of 3,917,366 cases reported to the World Health Organization. No specific treatments for reducing mortality or morbidity are yet available. Deaths from COVID-19 will continue to rise globally until effective and appropriate treatments and/or vaccines are found. In search of effective treatments, the global medical, scientific, pharma and funding communities have rapidly initiated over 500 COVID-19 clinical trials on a range of antiviral drug regimens and repurposed drugs in various combinations. A paradigm shift is underway from the current focus of drug development targeting the pathogen, to advancing cellular Host-Directed Therapies (HDTs) for tackling the aberrant host immune and inflammatory responses which underlie the pathogenesis of SARS-CoV-2 and high COVID-19 mortality rates. We focus this editorial specifically on the background to, and the rationale for, the use and evaluation of mesenchymal stromal (Stem) cells (MSCs) in treatment trials of patients with severe COVID-19 disease. Currently, the ClinicalTrials.gov and the WHO Clinical Trials Registry Platform (WHO ICTRP) report a combined 28 trials exploring the potential of MSCs or their products for treatment of COVID-19. MSCs should also be trialed for treatment of other circulating WHO priority Blueprint pathogens such as MERS-CoV which causes upto 34% mortality rates. It's about time funding agencies invested more into development MSCs per se, and also for a range of other HDTs, in combination with other therapeutic interventions. MSC therapy could turn out to be an important contribution to bringing an end to the high COVID-19 death rates and preventing long-term functional disability in those who survive disease.

Cellular Therapy: Shafts of Light Emerging for COVID-19

The COVID-19 pandemic has presented with debilitating respiratory consequences especially more pronounced in high risk individuals. Individuals with underlying systemic diseases are more prone and vulnerable to suffer severe consequences of SARS-CoV-2 infectivity. The pathophysiological changes identified cytokine storm mechanism for out setting the series of adverse clinical conditions. Thereby, associating it with high mortality rates. This warrants urgent consideration of divergent modalities such as the cellular therapy. Cellular therapy (CT) is a new medical paradigm wherein cellular material is administered to patients for therapeutic purposes. In this regard, mesenchymal stem cells (MSCs) have yielded the most promising results among stromal vascular fraction (SVF); placental cells; natural killer (NK) cell and platelet lysate respectively. Following the administration of the CT as per preferred route, these play pivotal role in modifying the microenvironment of the lung tissue with their distinct sets of mechanism. Evidences have shown how their immunomodulatory action repairs and prevents lung injury which in turn improvise the compliance of lungs. In this review article we have discussed these emerging novel approaches and their target step serving as a ray of hope to combat severe form of COVID-19. Currently these aren't approved for preventing or treating COVID-19 cases, however clinical trials are afoot to dispense the utmost understanding in terms of efficacy and safety concerns.

Veterinary Regenerative Medicine for Musculoskeletal Disorders: Can Mesenchymal Stem/Stromal Cells and Their Secretome Be the New Frontier?

Regenerative medicine aims to restore the normal function of diseased or damaged cells, tissues, and organs using a set of different approaches, including cell-based therapies. In the veterinary field, regenerative medicine is strongly related to the use of mesenchymal stromal cells (MSCs), which belong to the body repair system and are defined as multipotent progenitor cells, able to self-replicate and to differentiate into different cell types. This review aims to take stock of what is known about the MSCs and their use in the veterinary medicine focusing on clinical reports on dogs and horses in musculoskeletal diseases, a research field extensively reported in the literature data. Finally, a perspective regarding the use of the secretome and/or extracellular vesicles (EVs) in the veterinary field to replace parental MSCs is provided. The pharmaceuticalization of EVs is wished due to the realization of a Good Manufacturing Practice (GMP product suitable for clinical trials.

Micro-fragmented stromal-vascular fraction plus microfractures provides better clinical results than microfractures alone in symptomatic focal chondral lesions of the knee

PURPOSE

To evaluate clinical outcomes over a 1-year period in patients affected by symptomatic focal chondral lesions of the knee treated with micro-fragmented stromal-vascular fraction plus microfractures compared to microfractures alone.

METHODS

Two groups of 20 patients were arthroscopically treated with microfractures for a symptomatic focal chondral defect of the knee. At the end of surgery, in the experimental group, micro-fragmented stromal-vascular fraction was injected into the joint. Primary end point was WOMAC score at 12 months. Secondary end points were any adverse events, Oxford Knee Score, EQ-5D score, VAS for pain, analgesic and anti-inflammatory consumption.

RESULTS

All the patients were evaluated at 12-month follow-up. No adverse reactions were noted. Analgesic and anti-inflammatory consumption was similar in both groups. At 1-month follow-up, no differences were noted between groups when compared to pre-operative scores. At 3-month follow-up, patients in both groups improved from the baseline in all variables. Significantly lower VAS scores were found in the experimental group (4.2 ± 3.2 vs. 5.9 ± 1.7, p = 0.04). At 6- and 12-month follow-ups, patients in the experimental group scored better in all outcomes with a moderate effect size; in particular, better WOMAC scores were obtained at 12 months, achieving the primary end-point of the study (17.7 ± 11.1 vs. 25.5 ± 12.7; p = 0.03).

CONCLUSIONS

Injection of micro-fragmented stromal-vascular fraction is safe and, when associated with microfractures, is more effective in clinical terms than microfractures alone in patients affected by symptomatic focal chondral lesions of the knee. Results of the current study provide information that could help physicians to improve their counseling for patients concerning ADMSCs.

LEVEL OF EVIDENCE

Level 1-therapeutic study.

The quality evaluation system establishment of mesenchymal stromal cells for cell-based therapy products

BACKGROUND

Cell-based therapy products are supposed to be the most complex medicine products in the history of human medical care. In this study, we established a safety evaluation system for therapeutic stromal cells based on the existing regulations and current testing techniques to provide general quality requirements for human umbilical cord mesenchymal stromal cell (HUCMSC) therapy product.

METHODS

In this system, we comprehensively evaluate the environmental monitoring program, quality control of critical raw materials and reagents, donor screening criteria, cell safety, quality, and biological effects, not only in line with the basic criteria of biological products, but also following the general requirements of drugs.

RESULTS

The qualified HUCMSCs were tested for various clinical researches in our hospital, and no severe adverse reaction was observed in 225 patients during a 1-year follow-up period.

CONCLUSION

In this study, we establish a systemic quality control and potent assays to guarantee the safety and effectiveness of HUCMSCs based on a minimum set of standards in MSC-based product.

Mesenchymal Stem/Stromal Cell Production Compliant with Good Manufacturing Practice: Comparison between Bone Marrow, the Gold Standard Adult Source, and Wharton's Jelly, an Extraembryonic Source

Many clinical trials report mesenchymal stem/stromal cells (MSCs) efficacy in various indications. Therefore, standardization of MSC production becomes necessary. MSC properties are impacted by tissue origin, especially if they are from extraembryonic tissue or adult sources. For this reason, we evaluated the impact of MSC tissue origin on production. Methods: Three productions of MSC from Wharton’s Jelly (WJ) or from bone marrow (BM) were performed according to good manufacturing practice. The identity (phenotype, differentiation, and clonogenic capacities), safety (karyotype, telomerase activity, sterility, and donor qualification), and functionality (viability, mixed lymphocyte reaction) of each cell batch were analyzed. Results: Slight differences between MSC sources were observed for phenotype, telomerase activity, and clonogenic capacities. Conclusion: Both sources have made it possible to quickly and easily obtain clinical grade MSC. However, as availability of the source is thought to be essential, WJ seems more advantageous than BM.

Biomaterial-assisted scalable cell production for cell therapy

Cell therapy, the treatment of diseases using living cells, offers a promising clinical approach to treating refractory diseases. The global market for cell therapy is growing rapidly, and there is an increasing demand for automated methods that can produce large quantities of high quality therapeutic cells. Biomaterials can be used during cell production to establish a biomimetic microenvironment that promotes cell adhesion and proliferation while maintaining target cell genotype and phenotype. Here we review recent progress and emerging techniques in biomaterial-assisted cell production. The increasing use of auxiliary biomaterials and automated production methods provides an opportunity to improve quality control and increase production efficiency using standardized GMP-compliant procedures.

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.

Periostin expression and characters of human adipose tissue-derived mesenchymal stromal cells were aberrantly affected by in vitro cultivation

Background

Human adipose tissue-derived mesenchymal stromal cells (AD-MSCs) have been under focus in regenerative medicine since their discovery as a suitable source of MSCs. AD-MSCs are heterogeneous cells and exhibit variations in population doubling time, morphology and proliferative capacity. This study investigated if human AD-MSCs are developing, during in vitro long-term cultivation, in an unwanted or aberrant way.

Methods

This study monitored AD-MSCs during their in vitro culture till the tenth passage investigating proliferation kinetics, DNA index and surface markers expression. Also, periostin gene expression was examined.

Results

The proliferation capacity and colony forming unit were decreased after passage 6 and the population doubling time was increased. Flow cytometric analysis revealed that newly cultivated population strongly expressed MSCs markers, furthermore, reduction of CD105 expression appeared in passage 5 onwards, the later was associated with significant increase in expression of CD34 (a hematopoietic cell marker). Also, reduction of CD73 and CD90 expression was observed from passage 8. Furthermore, during the first six passages, periostin expression was significantly unchanged, with significant upregulation in late passages.

Conclusions

Long-term cultivation of human AD-MSCs changed their characters in an aberrant way and the first four passages might be the most appropriate passages for therapy. More investigation and understanding of these variations are needed to help in standardizing the expansion of MSCs-based therapies.

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.

Challenges and Controversies in Human Mesenchymal Stem Cell Therapy

Stem cell therapy is being intensely investigated within the last years. Expectations are high regarding mesenchymal stem cell (MSC) treatment in translational medicine. However, many aspects concerning MSC therapy should be profoundly defined. Due to a variety of approaches that are investigated, potential effects of stem cell therapy are not transparent. On the other hand, most results of MSC administration in vivo have confirmed their safety and showed promising beneficial outcomes. However, the therapeutic effects of MSC-based treatment are still not spectacular and there is a potential risk related to MSC applications into specific cell niche that should be considered in long-term observations and follow-up outcomes. In this review, we intend to address some problems and critically discuss the complex nature of MSCs in the context of their effective and safe applications in regenerative medicine in different diseases including graft versus host disease (GvHD) and cardiac, neurological, and orthopedic disorders.

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

BACKGROUND

Human Wharton's jelly-derived mesenchymal stromal cells (hWJSCs) have gained considerable attention for their use in cell therapy. Many of these applications would require manufacturing of millions of hWJSCs. It is, therefore, necessary to develop a Good Manufacturing Practice (GMP)-compliant hWJSC expansion protocol, allowing the generation of a large quantity of cells to meet both clinical and regulatory requirements. Here, we compared human platelet lysate (HPL) and human serum (HS) in supporting clinical-grade hWJSC expansion.

METHODS

hWJSCs were successfully isolated from six different umbilical cords using GMP-compliant dissociation enzymes. Freshly isolated hWJSCs were cultured in media supplemented with 10% of one of the following sera: fetal bovine serum (FBS), HPL and HS. Properties of the expanded hWJSCs were analyzed.

RESULTS

We showed that GMP-compliant dissociation enzymes were as efficient as research-grade dissociation enzymes in isolating hWJSCs. hWJSC fresh cell yield and cell viability using HPL and HS supplementations were at greater advantages than FBS. Moreover, hWJSCs expanded in HPL and HS supplementations not only preserved classical MSCs phenotypes and differentiation potential to adipocytes, osteocytes and chondrocytes, they also enhanced the migration of skin fibroblasts. However, HS, unlike HPL, did not alter immunogenicity properties of hWJSCs. hWJSCs expanded in HS supplementation also exerted greater immunosuppressive action in inhibiting T-cell proliferation and increased extracellular matrix (ECM) gene expression, making them useful in tissue repair clinical application.

CONCLUSION

Our findings indicate that HS can be considered as a promising and safer alternative to FBS, and should be recommended for clinical-grade expansion of hWJSCs.

Treatment of osteonecrosis of the femoral head by core decompression and implantation of fully functional ex vivo-expanded bone marrow-derived mesenchymal stem cells: a proof-of-concept study

Background

Based on several attributes involved in bone formation, bone marrow-resident mesenchymal stem cells (MSCs) have been employed in the treatment of patients suffering from femoral head osteonecrosis. Due to the low content of MSCs in the bone marrow, ex vivo expansion procedures are utilized to increase the cell number. Customarily, before administration of the resulting expanded cell product MSCs to the patient, its cellular identity is usually evaluated according to a set of “minimal phenotypic” markers, which are not modified by ex vivo processing. However, MSC functional (“reparative”) markers, which are severely impaired along the ex vivo expansion routine, are usually not assessed.

Patients and methods

In this proof-of-concept study, a cohort of five avascular osteonecrosis patients received an instillation of ex vivo-expanded autologous MSCs, manufactured under controlled conditions, with an aim to protect their functional (“reparative”) capacity.

Results and conclusion

Outcomes of this study confirmed the safety and effectiveness of the MSC-based therapy used. After a follow-up period (19–54 months), in all patients, the hip function was significantly improved and pain intensity markedly reduced. As a corollary, no patient required hip arthroplasty.

Single-Stage Preparation of Human Cartilage Grafts Generated from Bone Marrow-Derived CD271+ Mononuclear Cells

Due to the limited self-healing capacity of articular cartilage, innovative, regenerative approaches are of particular interest. The use of two-stage procedures utilizing in vitro-expanded mesenchymal stromal cells (MSCs) from various cell sources requires good manufacturing practice-compliant production, a process with high demands on time, staffing, and financial resources. In contrast, one- stage procedures are directly available, but need a safe enrichment of potent MSCs. CD271 is a surface marker known to marking the majority of native MSCs in bone marrow (BM). In this study, the feasibility of generating a single-stage cartilage graft of enriched CD271⁺ BM-derived mononuclear cells (MNCs) without in vitro monolayer expansion from eight healthy donors was investigated. Cartilage grafts were generated by magnetic-activated cell sorting and separated cells were directly transferred into collagen type I hydrogels, followed by 3D proliferation and differentiation period of CD271⁺, CD271^-, or unseparated MNCs. CD271⁺ MNCs showed the highest proliferation rate, cell viability, sulfated glycosaminoglycan deposition, and cartilage marker expression compared to the CD271^- or unseparated MNC fractions in 3D culture. Analysis according to the minimal criteria of the International Society for Cellular Therapy highlighted a 66.8-fold enrichment of fibroblast colony-forming units in CD271⁺ MNCs and the only fulfillment of the MSC marker profile compared to unseparated MNCs. In summary, CD271⁺ MNCs are capable of generating adequate articular cartilage grafts presenting high cell viability and notable chondrogenic matrix deposition in a CE-marked collagen type I hydrogel, which can obviate the need for an initial monolayer expansion.

Phenotypic Identification of Dental Pulp Mesenchymal Stem/Stromal Cells Subpopulations with Multiparametric Flow Cytometry

Dental pulp (DP) is a specialized, highly vascularized, and innervated connective tissue mainly composed of undifferentiated mesenchymal cells, fibroblasts, and highly differentiated dentin-forming odontoblasts. Undifferentiated mesenchymal cells include stem/stromal cell populations usually called dental pulp mesenchymal stem cells (DP-MSCs) which differ in their self-renewal properties, lineage commitment, and differentiation capabilities. Analysis of surface antigens has been largely used to precisely identify these DP-MSC populations. However, a major difficulty is that these antigens are actually not specific for MSCs. Most of the markers used are indeed shared by other cell populations such as progenitor cells, mature fibroblasts, and/or perivascular cells. Accordingly, the detection of only one of these markers in a cell population is clearly insufficient to determine its stemness. Recent data reported that multiparametric flow cytometry, by allowing for the detection of several molecules on the surface of one single cell, is a powerful tool to elucidate the phenotype of a cell population both in vivo and in vitro. So far, DP-MSC populations have been characterized mainly based on the isolated expression of molecules known to be expressed by stem cells, such as Stro-1 antigen, melanoma cell adhesion molecule MCAM/CD146, low-affinity nerve growth factor receptor p75NTR/CD271, and the mesenchymal stem cell antigen MSCA-1. Using multiparametric flow cytometry, we recently showed that human DP-MSCs are indeed phenotypically heterogeneous and form several populations.The present paper describes the multiparametric flow cytometry protocol we routinely use for characterizing DP-MSCs. The description includes the design of the antibody panel and explains the selection of the different parameters related to the data quality control.

Levels of IL-17F and IL-33 correlate with HLA-DR activation in clinical-grade human bone marrow-derived multipotent mesenchymal stromal cell expansion cultures

BACKGROUND AIMS

Multipotent mesenchymal stromal cell (MSC)-based medicines are extensively investigated for use in regenerative medicine and immunotherapy applications. The International Society for Cell and Gene Therapy (ISCT) proposed a panel of cell surface molecules for MSC identification that includes human leukocyte antigen (HLA)-DR as a negative marker. However, its expression is largely unpredictable despite production under tightly controlled conditions and compliance with current Good Manufacturing Practices. Herein, we report the frequency of HLA-DR expression in 81 batches of clinical grade bone marrow (BM)-derived MSCs and investigated its impact on cell attributes and culture environment.

METHODS

The levels of 15 cytokines (interleukin [IL]-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon-γ, soluble CD40 ligand and tumor necrosis factor-α) were determined in sera supplements and supernatants of BM-MSC cultures. Identity, multipotentiality and immunopotency assays were performed on high (>20% of cells) and low (≤20% of cells) HLA-DR⁺ cultures.

RESULTS

A correlation was found between HLA-DR expression and levels of IL-17F and IL-33. Expression of HLA-DR did neither affect MSC identity, in vitro tri-lineage differentiation potential (into osteogenic, chondrogenic and adipogenic lineages), nor their ability to inhibit the proliferation of stimulated lymphocytes.

DISCUSSION

Out of 81 batches of BM-MSCs for autologous use analyzed, only three batches would have passed the ISCT criteria (<2%), whereas 60.5% of batches were compliant with low HLA-DR values (≤20%). Although a cause-effect relationship cannot be drawn, we have provided a better understanding of signaling events and cellular responses in expansion culture conditions relating with HLA-DR expression.

Pilot Production of Mesenchymal Stem/Stromal Freeze-Dried Secretome for Cell-Free Regenerative Nanomedicine: A Validated GMP-Compliant Process

In this paper, a pilot production process for mesenchymal stem/stromal freeze-dried secretome was performed in a validated good manufacturing practice (GMP)-compliant cell factory. Secretome was purified from culture supernatants by ultrafiltration, added to cryoprotectant, lyophilized and characterized. We obtained a freeze-dried, "ready-off-the-shelf" and free soluble powder containing extracellular vesicles and proteins. In the freeze-dried product, a not-aggregated population of extracellular vesicles was detected by nanoparticle tracking analysis; Fourier transform infrared spectra showed the simultaneous presence of protein and lipids, while differential scanning calorimetry demonstrated that lyophilization process successfully occurred. A proteomic characterization allowed the identification of proteins involved in immune response, response to stress, cytoskeleton and metabolism. Moreover, the product was not cytotoxic up to concentrations of 25 mg/mL (on human fibroblasts, chondrocytes and nucleus pulposus cells by MTT assay) and was blood compatible up to 150 mg/mL. Finally, at concentrations between 5 and 50 mg/mL, freeze-dried secretome showed to in vitro counteract the oxidative stress damage induced by H₂O₂ on nucleus pulposus cells by MTT assay.

Adipose tissue-derived mesenchymal stromal cells for clinical application: An efficient isolation approach

PURPOSE OF THE STUDY

Mesenchymal stromal cells (MSCs) are considered a promising tool for cell therapy approaches. The translation of research-based cell culture protocols into procedures that comply with Good Manufacturing Practice (GMP) is critical. The aim of this study was to design a new method for the expansion of MSCs from Adipose Tissue (AT-MSCs) in compliance with GMP, without enzymatic tissue digestion and without the use of animal proteins as source of growth factors.

PATIENTS AND METHODS

MSCs were expanded from 10 periumbilical biopsies. Our new isolation approach is based on: (1) disruption of AT with an automated, closed system; (2) use of GMP-grade medium without the addition of fetal bovine serum or platelet lysate; (3) use of human recombinant Trypsin. AT-MSCs cultured in α-MEM and minced by scalpel were used as control.

RESULTS

It was possible to expand MSCs from all the AT-samples for at least eight passages. MSCs displayed the typical spindle-shape morphology, a high viability, multilineage differentiation potential and high expression levels of the typical MSC-specific surface antigens and genes. Compared to standard method, MSCs obtained with the new method showed higher yield, up to passage 6, and higher purity in terms of percentage of CD34 and CD45 markers. All AT-MSCs exhibit in vitro immunosuppressive capacity and possess a normal karyotype.

CONCLUSIONS

Our data clearly demonstrate that our new approach permits to generate AT-MSCs fully compliant for therapeutic use and better at least in terms of quantity and purity than those obtained with the standard method.

Micro-fragmented adipose tissue injection associated with arthroscopic procedures in patients with symptomatic knee osteoarthritis

BACKGROUND

The social impact of degenerative diseases is steadily increasing, because of the continued rise in the mean age of the active population. Articular cartilage lesions are generally associated with disability and symptoms such as joint pain and reduced function, and remain a challenge for the orthopaedic surgeon. Several non-invasive solution have been proposed, but the results achieved to date are far from being completely satisfactory. Recently, new therapeutic approaches, such as the use of mesenchymal stem cells, have been developed. Among the many sources, the adipose tissue is nowadays considered one of the smartest, due to its abundance and easy access. The aim of this retrospective study is to explore whether patients affected by symptomatic knee osteoarthritis treated with micro-fragmented adipose tissue associated with a chondral shaving procedure experience an improvement in symptoms and function.

METHODS

Thirty-eight patients affected by symptomatic knee osteoarthritis were treated in 2015 with an arthroscopic procedure associated with an injection of autologous and micro-fragmented adipose tissue. Micro-fragmented adipose tissue was obtained using a minimal manipulation technique in a closed system. Clinical outcomes were determined at 1, 3, 6, and 12 months follow-up using Knee Injury and Osteoarthritis Outcome Score questionnaire and direct physical examination. Safety of the procedure, recording type and incidence of any adverse event, was also assessed.

RESULTS

A steady and statistically significant improvement of all the clinical scores from pre-operative evaluation to 1, 3, 6, and 12 months follow-up was observed, with KOOS sport and quality of life being the most improved scores. On average, 92% of the patients clinically improved and 100% of them were satisfied with the treatment. No adverse events nor relevant complications were recorded.

CONCLUSION

The result of the study pointed to micro-fragmented adipose tissue as a safe and beneficial adjuvant in the surgical treatment of degenerative knee chondropathy. The procedure is simple, sustainable, quick, minimally invasive, one-step, and safe. After one year, the results are very satisfactory and promising. A longer follow-up is needed to draw definitive conclusions and enlarge the indications.

TRIAL REGISTRATION

Registered at clinicaltrials.gov as NCT03527693 on 27 April 2018 (retrospectively registered).

Isolating Pediatric Mesenchymal Stem Cells with Enhanced Expansion and Differentiation Capabilities

Mesenchymal stem cells/marrow stromal cells (MSCs) are attractive for applications ranging from research and development to use in clinical therapeutics. However, the most commonly studied MSCs, adult bone marrow MSCs (A-MSCs), are limited by significant donor variation resulting in inconsistent expansion rates and multilineage differentiation capabilities. We have recently obtained permission to isolate pediatric MSCs (P-MSCs) from surplus iliac crest bone chips. Here, we developed a simple and easily replicable isolation protocol yielding P-MSCs, which adhere to MSC defining guidelines. After confirming immunophenotypic marker expression, we compared expansion rates, senescence, morphology, and trilineage differentiation of P-MSCs to A-MSCs for multiple donors. We found P-MSCs have faster in vitro replication, consistently show significantly lower senescence, and are capable of more reproducible multilineage differentiation than A-MSCs. We, therefore, believe P-MSCs are a promising candidate for use in research applications and potentially as part of an allogeneic therapeutic treatment.

Mesenchymal Stromal Cells: From Discovery to Manufacturing and Commercialization

Over the last decades, mesenchymal stromal cells (MSC) have been the focus of intense research by academia and industry due to their unique features. MSC can be easily isolated and expanded through in vitro culture by taking full advantage of their self-renewing capacity. In addition, MSC exert immunomodulatory effects and can be differentiated into various lineages, which makes them highly attractive for clinical applications in cell-based therapies. In this review, we attempt to provide a brief historical overview of MSC discovery, characterization, and the first clinical studies conducted. The current MSC manufacturing platforms are reviewed with special attention regarding the use of bioreactors for the production of GMP-compliant clinically relevant cell numbers. The first commercial MSC-based products are also addressed, as well as the remaining challenges to the widespread use of MSC-derived products.

Adipose-Derived Mesenchymal Stem Cells in the Use of Cartilage Tissue Engineering: The Need for a Rapid Isolation Procedure

Mesenchymal stem cells (MSCs) have shown much promise with respect to their use in cartilage tissue engineering. MSCs can be obtained from many different tissue sources. Among these, adipose tissue can provide an abundant source of adipose-derived mesenchymal stem cells (ADMSCs). The infrapatellar fat pad (IFP) is a promising source of ADMSCs with respect to producing a cartilage lineage. Cell isolation protocols to date are time-consuming and follow conservative approaches that rely on a long incubation period of 24–48 hours. The different types of ADMSC isolation techniques used for cartilage repair will be reviewed and compared with the view of developing a rapid one-step isolation protocol that can be applied in the context of a surgical procedure.

The regenerative therapies of the ankle degeneration: a focus on multipotential mesenchymal stromal cells

The ankle degeneration ranging from focal osteochondral lesions to osteoarthritis can cause a total joint function loss. With rising life expectancy and activity of the patients, various regenerative therapies were introduced aiming to preserve the joint function via the induction of cartilage and bone repair. Here, biological events and mechanical changes of the ankle degeneration were discussed. The regenerative therapies were reviewed versus the standard surgical treatment. We especially focused on the use of mesenchymal (multipotential) stromal cells (MSCs) highlighting their dual functions of regeneration and cell modulation with an emphasis on the emerging MSC-based clinical studies. Being at an early step, more basic and clinical research is needed to optimize the applications of all ankle regenerative therapies including MSC-based methods.

A Nonenzymatic and Automated Closed-Cycle Process for the Isolation of Mesenchymal Stromal Cells in Drug Delivery Applications

The adipose tissue is a good source of mesenchymal stromal cells that requires minimally invasive isolation procedures. To ensure reproducibility, efficacy, and safety for clinical uses, these procedures have to be in compliant with good manufacturing practices. Techniques for harvesting and processing human adipose tissue have rapidly evolved in the last years, and Lipogems® represents an innovative approach to obtain microfragmented adipose tissue in a short time, without expansion and/or enzymatic treatment. The aim of this study was to assess the presence of mesenchymal stromal cells in the drain bag of the device by using a prototype Lipogems processor to wash the lipoaspirate in standardized condition. We found that, besides oil and blood residues, the drain bag contained single isolated cells easy to expand and with the typical characteristics of mesenchymal stromal cells that can be loaded with paclitaxel to use for drug-delivery application. Our findings suggest the possibility to replace the drain bag with a "cell culture chamber" obtaining a new integrated device that, without enzymatic treatment, can isolate and expand mesenchymal stromal cells in one step with high good manufacturing practices compliance. This system could be used to obtain mesenchymal stromal cells for regenerative purposes and for drug delivery.

Ubiquitin C decrement plays a pivotal role in replicative senescence of bone marrow mesenchymal stromal cells

Human bone marrow-mesenchymal stromal cells (hBM-MSCs) undergo cellular senescence during in vitro culture. In this study, we defined this replicative senescence as impaired proliferation, deterioration in representative cell characteristics, accumulated DNA damage, and decreased telomere length and telomerase activity with or without genomic abnormalities. The UBC gene expression gradually decreased during passaging along with the reduction in series of molecules including hub genes; CDK1, CCNA2, MCM10, E2F1, BRCA1, HIST1H1A and HIST1H3B. UBC knockdown in hBM-MSCs induced impaired proliferation in dose-dependent manner and showed replicative senescence-like phenomenon. Gene expression changes after UBC knockdown were similar to late passage hBM-MSCs. Additionally, UBC overexpession improved the proliferation activity of hBM-MSCs accompanied by increased expression of the hub genes. Consequently, UBC worked in higher-order through regulation of the hub genes controlling cell cycle and proliferation. These results indicate that the decrement of UBC expression plays a pivotal role in replicative senescence of hBM-MSCs.

Methods and practices to diversify cell-based products

Medicinal signaling cell (MSC)-based products represent emerging treatments in various therapeutic areas including cardiometabolic, inflammation, autoimmunity, orthopedics, wound healing and oncology. Exploring innovation beyond minimally manipulated plastic-adherent ex vivo expanded allogeneic MSCs enables product delineation. Product delineation is on the critical path to maximize clinical benefits and market access. An innovation framework is presented here along various innovation dimensions comprising composition-of-matter by means of positive cell surface markers, formulation varying for example the cell dose or the preservation mode and medium, manufacturing to adapt the secretome of MSCs to the condition of interest, the mode of delivery and corresponding delivery devices, as well as molecular engineering and biomarkers. The rationale of the innovation space thus described applies generally to all cell-based therapies.