Critical View on Mesenchymal Stromal Cells in Regenerative Medicine

hP-MSCs attenuate severe acute pancreatitis in mice via inhibiting NLRP3 inflammasome-mediated acinar cell pyroptosis

BACKGROUND

Severe acute pancreatitis (SAP) is a serious gastrointestinal disease that is facilitated by pancreatic acinar cell death. The protective role of human placental mesenchymal stem cells (hP-MSCs) in SAP has been demonstrated in our previous studies. However, the underlying mechanisms of this therapy remain unclear. Herein, we investigated the regularity of acinar cell pyroptosis during SAP and investigated whether the protective effect of hP-MSCs was associated with the inhibition of acinar cell pyroptosis.

METHODS

A mouse model of SAP was established by the retrograde injection of sodium taurocholate (NaTC) solution in the pancreatic duct. For the hP-MSCs group, hP-MSCs were injected via the tail vein and were monitored in vivo. Transmission electron microscopy (TEM) was used to observe the pyroptosis-associated ultramorphology of acinar cells. Immunofluorescence and Western blotting were subsequently used to assess the localization and expression of pyroptosis-associated proteins in acinar cells. Systemic inflammation and local injury-associated parameters were evaluated.

RESULTS

Acinar cell pyroptosis was observed during SAP, and the expression of pyroptosis-associated proteins initially increased, peaked at 24 h, and subsequently showed a decreasing trend. hP-MSCs effectively attenuated systemic inflammation and local injury in the SAP model mice. Importantly, hP-MSCs decreased the expression of pyroptosis-associated proteins and the activity of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in acinar cells.

CONCLUSIONS

Our study demonstrates the regularity and important role of acinar cell pyroptosis during SAP. hP-MSCs attenuate inflammation and inhibit acinar cell pyroptosis via suppressing NLRP3 inflammasome activation, thereby exerting a protective effect against SAP.

The origin, progress, and application of cell-based cardiac regeneration therapy

Cardiovascular disease (CVD) has become a severe threat to human health, with morbidity and mortality increasing yearly and gradually becoming younger. When the disease progresses to the middle and late stages, the loss of a large number of cardiomyocytes is irreparable to the body itself, and clinical drug therapy and mechanical support therapy cannot reverse the development of the disease. To explore the source of regenerated myocardium in model animals with the ability of heart regeneration through lineage tracing and other methods, and develop a new alternative therapy for CVDs, namely cell therapy. It directly compensates for cardiomyocyte proliferation through adult stem cell differentiation or cell reprogramming, which indirectly promotes cardiomyocyte proliferation through non-cardiomyocyte paracrine, to play a role in heart repair and regeneration. This review comprehensively summarizes the origin of newly generated cardiomyocytes, the research progress of cardiac regeneration based on cell therapy, the opportunity and development of cardiac regeneration in the context of bioengineering, and the clinical application of cell therapy in ischemic diseases.

Transplanted mesenchymal stromal cells are unable to migrate to the bone surface and subsequently improve osteogenesis in glucocorticoid-induced osteoporosis

Long-term or high-dose use of glucocorticoids causes bone loss and low bone formation. We previously demonstrated that dexamethasone (Dex) administration caused the shifted differentiation balance of mesenchymal stromal cells (MSCs) to favor adipogenic lineage over osteoblastic lineage, which is one of the key mechanisms for Dex-induced osteoporosis (DIO). These findings indicate that supplementing functional allogeneic MSCs could be a therapeutic strategy for DIO. Here, we found that transplanting MSCs by intramedullary injection had little effect in promoting new bone formation. Fluorescent-labeled lineage tracing revealed that 1 week after transplantation, green fluorescent protein (GFP)-MSCs were found to migrate to the bone surface (BS) in control mice but not in DIO mice. As expected, GFP-MSCs on the BS were mostly Runx2-positive; however, GFP-MSCs located away from the BS failed to differentiate into osteoblasts. We further discovered that the levels of transforming growth factor beta 1 (TGF-β1), one of the main chemokines for MSC migration, is significantly decreased in the bone marrow fluid of DIO mice, which is insufficient to direct MSC migration. Mechanistically, Dex inhibits TGF-β1 expression by down-regulating its promoter activity, which decreases bone matrix-deposited TGF-β1 as well as active TGF-β1 released during osteoclast-mediated bone resorption. This study indicates that blocking MSC migration in osteoporotic BM contributes to bone loss and suggests that MSC mobilization to the BS may be a promising target for treating osteoporosis.

Identifying Biomarkers for Osteogenic Potency Assay Development

There has been extensive exploration of how cells may serve as advanced therapy medicinal products to treat skeletal pathologies. Osteoblast progenitors responsible for production of extracellular matrix that is subsequently mineralized during bone formation have been characterised as a rare bone marrow subpopulation of cell culture plastic adherent cells. Conveniently, they proliferate to form single-cell derived colonies of fibroblastoid cells, termed colony forming unit fibroblasts that can subsequently differentiate to aggregates resembling small areas of cartilage or bone. However, donor heterogeneity and loss of osteogenic differentiation capacity during extended cell culture have made the discovery of reliable potency assay biomarkers difficult. Nonetheless, functional osteoblast models derived from telomerised human bone marrow stromal cells have allowed extensive comparative analysis of gene expression, microRNA, morphological phenotypes and secreted proteins. This chapter highlights numerous insights into the molecular mechanisms underpinning osteogenic differentiation of multipotent stromal cells and bone formation, discussing aspects involved in the choice of useful biomarkers for functional attributes that can be quantitively measured in osteogenic potency assays.

The Art of Stem Cell-Based Therapy

Potency assays represent crucial experiments at the hub of the comprehensive complexity surrounding cell therapy. Moreover, numerous factors beyond biological and scientific considerations are involved in achieving successful potency assays that fulfil regulatory authority approval for a new advanced therapy medicinal product. Though this can mean a frustratingly long period of discovery and development, progress in cell therapy is nowadays proceeding remarkably quickly, assisted by the potency assay rigorously placing emphasis on the need to critically analyse the key factor/s responsible for the therapeutic mechanism of action. History has shown that it can take many decades for there to be an improved understanding of a mechanism of action. Yet the chasing of precise targets has revolutionised medicine, with no clearer example than approaches to viral pandemics. The centuries involved in the eradication of smallpox have paved the way for an unprecedented pace of vaccine development for the Covid-19 pandemic. Such extraordinary accomplishments foster encouragement that similarly for stem cell-based therapy, our scientific knowledge will continue to improve apace. This chapter focuses on the art of experimentation and discovery, introducing potency assay requisites and numerous factors that can influence potency assay outcomes. A comprehensive understanding of potency assays and their development can hasten the provision of new cell therapies to help resolve burdensome diseases of unmet medical need.

Cargo proteins in extracellular vesicles: potential for novel therapeutics in non-alcoholic steatohepatitis

BACKGROUND

Extracellular vesicles (EVs) are recognized as novel cell-free therapeutics. Non-alcoholic steatohepatitis (NASH) remains a critical health problem. Herein, we show that EVs from pan peroxisome proliferator-activated receptor agonist-primed induced mesenchymal stem cell (pan PPAR-iMSC-EVs) has unique cargo protein signatures, and demonstrate its therapeutic function in NASH.

RESULTS

A unique protein signatures were identified in pan PPAR-iMSC-EVs against those from non-stimulated iMSC-EVs. NASH mice receiving pan PPAR-iMSC-EVs showed reduced steatotic changes and ameliorated ER stress and mitochondiral oxidative stress induced by inflammation. Moreover, pan PPAR-iMSC-EVs promoted liver regeneration via inhibiting apoptosis and enhancing proliferation.

CONCLUSIONS

We conclude that our strategy for enriching unique cargo proteins in EVs may facilitate the development of novel therapeutic option for NASH.

Nerve growth factor (NGF) and NGF receptors in mesenchymal stem/stromal cells: Impact on potential therapies

Mesenchymal stem/stromal cells (MSCs) are promising for the treatment of degenerative diseases and traumatic injuries. However, MSC engraftment is not always successful and requires a strong comprehension of the cytokines and their receptors that mediate the biological behaviors of MSCs. The effects of nerve growth factor (NGF) and its two receptors, TrkA and p75NTR, on neural cells are well studied. Increasing evidence shows that NGF, TrkA, and p75NTR are also involved in various aspects of MSC function, including their survival, growth, differentiation, and angiogenesis. The regulatory effect of NGF on MSCs is thought to be achieved mainly through its binding to TrkA. p75NTR, another receptor of NGF, is regarded as a novel surface marker of MSCs. This review provides an overview of advances in understanding the roles of NGF and its receptors in MSCs as well as the effects of MSC‐derived NGF on other cell types, which will provide new insight for the optimization of MSC‐based therapy.

Bone marrow mesenchymal stem cells transfer in patients with ST-segment elevation myocardial infarction: single-blind, multicenter, randomized controlled trial

OBJECTIVE

Our aim was to evaluate the efficacy and safety of intracoronary autologous bone marrow mesenchymal stem cell (BM-MSC) transplantation in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

In this randomized, single-blind, controlled trial, patients with STEMI (aged 39-76 years) were enrolled at 6 centers in Beijing (The People's Liberation Army Navy General Hospital, Beijing Armed Police General Hospital, Chinese People's Liberation Army General Hospital, Beijing Huaxin Hospital, Beijing Tongren Hospital, Beijing Chaoyang Hospital West Hospital). All patients underwent optimum medical treatment and percutaneous coronary intervention and were randomly assigned in a 1:1 ratio to BM-MSC group or control group. The primary endpoint was the change of myocardial viability at the 6th month's follow-up and left ventricular (LV) function at the 12th month's follow-up. The secondary endpoints were the incidence of cardiovascular event, total mortality, and adverse event during the 12 months' follow-up. The myocardial viability assessed by single-photon emission computed tomography (SPECT). The left ventricular ejection fraction (LVEF) was used to assess LV function. All patients underwent dynamic ECG and laboratory evaluations. This trial is registered with ClinicalTrails.gov, number NCT04421274.

RESULTS

Between March 2008 and July 2010, 43 patients who had underwent optimum medical treatment and successful percutaneous coronary intervention were randomly assigned to BM-MSC group (n = 21) or control group (n = 22) and followed-up for 12 months. At the 6th month's follow-up, there was no significant improvement in myocardial activity in the BM-MSC group before and after transplantation. Meanwhile, there was no statistically significant difference between the two groups in the change of myocardial perfusion defect index (p = 0.37) and myocardial metabolic defect index (p = 0.90). The LVEF increased from baseline to 12 months in the BM-MSC group and control group (mean baseline-adjusted BM-MSC treatment differences in LVEF 4.8% (SD 9.0) and mean baseline-adjusted control group treatment differences in LVEF 5.8% (SD 6.04)). However, there was no statistically significant difference between the two groups in the change of the LVEF (p = 0.23). We noticed that during the 12 months' follow-up, except for one death and one coronary microvascular embolism in the BM-MSC group, no other events occurred and alanine transaminase (ALT) and C-reactive protein (CRP) in BM-MSC group were significantly lower than that in the control group.

CONCLUSIONS

The present study may have many methodological limitations, and within those limitations, we did not identify that intracoronary transfer of autologous BM-MSCs could largely promote the recovery of LV function and myocardial viability after acute myocardial infarction.

Mesenchymal Stem Cell-derived Extracellular Vesicles for Skin Wound Healing

Skin is vulnerable to various external insults such as burn, severe injury, or inflammation, which necessitates a better strategy for wound repair. Mesenchymal stem cells (MSCs) can self-renew and differentiate into various supporting tissues including cartilage, bone, muscle, and adipose tissue. Along with their unique multipotent capacity, they secrete various paracrine mediators such as growth factors, cytokines, and membrane-enclosed particles called extracellular vesicles (EVs). Herein, we discussed the general traits of EVs such as cell-to-cell communicator, and highlighted the recent preclinical outcomes, with a focus on the application of MSC-derived EVs in wound repair. This chapter provides insights into developing novel strategies for skin wound healing in a cell-free manner.

Exosomal miR-499a-5p Inhibits Endometrial Cancer Growth and Metastasis via Targeting VAV3

Background/Aim

The current therapeutic strategies for endometrial cancer are limited and unsatisfactory. Accumulating evidence suggest that microRNAs (miRNAs) participate in tumor growth and metastasis. Mesenchymal stem cells (MSCs) derived exosomes (Exos) are considered as better miRNA delivery vehicles. Here, we investigated the therapeutic effect of exosomal miR-499a-5p (miR-499) in human endometrial cancer metastasis.

Methods

Microarray analysis and RT-PCR were performed to detect the relative expression of miR-499 in endometrial cancer tissues and cell lines. MSC-derived Exos were characterized by transmission electron microscope (TEM), Western blot (WB), and nanoparticle tracking analysis (NTA). miR-499 was loading into Exos using electroporation. Cell proliferation and angiogenesis capacity were tested by 5-ethynyl-29-deoxyuridine (EdU) assay and tube formation assay, respectively. Dual-luciferase reporter assay (DLR) was used to confirm the connection of miR-499 and VAV3.

Results

We found that the expression of miR-499 was significantly downregulated in cancer tissues compared with adjacent tissues in endometrial cancer patients. Moreover, exosomal miR-499 not only dramatically suppressed endometrial cancer cells proliferation, endothelial cells tube formation in vitro, but also inhibited tumor growth and angiogenesis in vivo. In addition, we confirmed that miR-499 directly targets the 3'UTR sequence of VAV3.

Conclusion

The novel identified exosomal miR-499 functions as a tumor suppressor in endometrial cancer though regulating VAV3, and these findings could be a valid molecular target for endometrial cancer therapy.

Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, in Contrast to Adipose Tissue-Derived Stromal Cells, Efficiently Improve Heart Function in Murine Model of Myocardial Infarction

Cell therapies are extensively tested to restore heart function after myocardial infarction (MI). Survival of any cell type after intracardiac administration, however, may be limited due to unfavorable conditions of damaged tissue. Therefore, the aim of this study was to evaluate the therapeutic effect of adipose-derived stromal cells (ADSCs) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) overexpressing either the proangiogenic SDF-1α or anti-inflammatory heme oxygenase-1 (HO-1) in a murine model of MI. ADSCs and hiPSCs were transduced with lentiviral vectors encoding luciferase (Luc), GFP and either HO-1 or SDF-1α. hiPSCs were then differentiated to hiPSC-CMs using small molecules modulating the WNT pathway. Genetically modified ADSCs were firstly administered via intracardiac injection after MI induction in Nude mice. Next, ADSCs-Luc-GFP and genetically modified hiPSC-CMs were injected into the hearts of the more receptive NOD/SCID strain to compare the therapeutic effect of both cell types. Ultrasonography, performed on days 7, 14, 28 and 42, revealed a significant decrease of left ventricular ejection fraction (LVEF) in all MI-induced groups. No improvement of LVEF was observed in ADSC-treated Nude and NOD/SCID mice. In contrast, administration of hiPSC-CMs resulted in a substantial increase of LVEF, occurring between 28 and 42 days after MI, and decreased fibrosis, regardless of genetic modification. Importantly, bioluminescence analysis, as well as immunofluorescent staining, confirmed the presence of hiPSC-CMs in murine tissue. Interestingly, the luminescence signal was strongest in hearts treated with hiPSC-CMs overexpressing HO-1. Performed experiments demonstrate that hiPSC-CMs, unlike ADSCs, are effective in improving heart function after MI. Additionally, long-term evaluation of heart function seems to be crucial for proper assessment of the effect of cell administration.

Apoptotic bodies derived from mesenchymal stem cells promote cutaneous wound healing via regulating the functions of macrophages

BACKGROUND

As the major interface between the body and the external environment, the skin is liable to various injuries. Skin injuries often lead to severe disability, and the exploration of promising therapeutic strategies is of great importance. Exogenous mesenchymal stem cell (MSC)-based therapy is a potential strategy due to the apparent therapeutic effects, while the underlying mechanism is still elusive. Interestingly, we observed the extensive apoptosis of exogenous bone marrow mesenchymal stem cells (BMMSCs) in a short time after transplantation in mouse skin wound healing models. Considering the roles of extracellular vesicles (EVs) in intercellular communication, we hypothesized that the numerous apoptotic bodies (ABs) released during apoptosis may partially contribute to the therapeutic effects.

METHODS

ABs derived from MSCs were extracted, characterized, and applied in mouse skin wound healing models, and the therapeutic effects were evaluated. Then, the target cells of ABs were explored, and the effects of ABs on macrophages were investigated in vitro.

RESULTS

We found ABs derived from MSCs promoted cutaneous wound healing via triggering the polarization of macrophages towards M2 phenotype. In addition, the functional converted macrophages further enhanced the migration and proliferation abilities of fibroblasts, which together facilitated the wound healing process.

CONCLUSIONS

Collectively, our study demonstrated that transplanted MSCs promoted cutaneous wound healing partially through releasing apoptotic bodies which could convert the macrophages towards an anti-inflammatory phenotype that plays a crucial role in the tissue repair process.

Muscle and cardiac therapeutic strategies for Duchenne muscular dystrophy: past, present, and future

BACKGROUND

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration and results in functional decline, loss of ambulation and early death of young men due to cardiac or respiratory failure. Although the major cause of the disease has been known for many years-namely mutation in the DMD gene encoding dystrophin, one of the largest human genes-DMD is still incurable, and its treatment is challenging.

METHODS

A comprehensive and systematic review of literature on the gene, cell, and pharmacological experimental therapies aimed at restoring functional dystrophin or to counteract the associated processes contributing to disease progression like inflammation, fibrosis, calcium signaling or angiogenesis was carried out.

RESULTS

Although some therapies lead to satisfying effects in skeletal muscle, they are highly ineffective in the heart; therefore, targeting defective cardiac and respiratory systems is vital in DMD patients. Unfortunately, most of the pharmacological compounds treat only the symptoms of the disease. Some drugs addressing the underlying cause, like eteplirsen, golodirsen, and ataluren, have recently been conditionally approved; however, they can correct only specific mutations in the DMD gene and are therefore suitable for small sub-populations of affected individuals.

CONCLUSION

In this review, we summarize the possible therapeutic options and describe the current status of various, still imperfect, strategies used for attenuating the disease progression.

Oral and Craniofacial Stem Cells: An Untapped Source for Neural Tissue Regeneration

Nerve tissue regeneration continues to represent an intractable obstacle to realizing the promise of tissue engineering. Although neurobiology works to shed light on the mechanisms governing neuronal growth and repair, considerable technical gaps remain that hinder progress. Chief among these is the absence of an appropriate culture environment to faithfully reproduce the neuronal niche ex vivo. We propose that the various multipotent cells found in the oral cavity may represent an important yet underutilized resource for preparing such neurogenic microenvironments. Similar to those of nerve tissue, these cell populations are of ectodermal origin and have clinically demonstrated neurogenic potential. Although there is a lack of consensus on whether putative types of oral and craniofacial stem cells constitute distinct populations, their contribution to neural tissue engineering may be twofold: as a cellular feedstock for neoneurogenesis and for the production of specialized in vitro environments for neurogenic differentiation, phenotype maintenance, and use in therapeutic applications. Impact statement We propose that addressing gaps in understanding the neurogenic role of dental stem cells and their microenvironment may yield efficient and reliable strategies for long-term neuronal cell culture and open new avenues for neural regeneration in both dental, nerve, and other tissues.

Mechanisms behind the Immunoregulatory Dialogue between Mesenchymal Stem Cells and Th17 Cells

Mesenchymal stem cells (MSCs) exhibit potent immunoregulatory abilities by interacting with cells of the adaptive and innate immune system. In vitro, MSCs inhibit the differentiation of T cells into T helper 17 (Th17) cells and repress their proliferation. In vivo, the administration of MSCs to treat various experimental inflammatory and autoimmune diseases, such as rheumatoid arthritis, type 1 diabetes, multiple sclerosis, systemic lupus erythematosus, and bowel disease showed promising therapeutic results. These therapeutic properties mediated by MSCs are associated with an attenuated immune response characterized by a reduced frequency of Th17 cells and the generation of regulatory T cells. In this manuscript, we review how MSC and Th17 cells interact, communicate, and exchange information through different ways such as cell-to-cell contact, secretion of soluble factors, and organelle transfer. Moreover, we discuss the consequences of this dynamic dialogue between MSC and Th17 well described by their phenotypic and functional plasticity.

Muscular Contribution to Adolescent Idiopathic Scoliosis from the Perspective of Stem Cell-Based Regenerative Medicine

Adolescent idiopathic scoliosis (AIS) is a relatively frequent disease within a range 0.5%-5.0% of population, with higher frequency in females. While a resultant spinal deformity is usually medically benign condition, it produces far going psychosocial consequences, which warrant attention. The etiology of AIS is unknown and current therapeutic approaches are symptomatic only, and frequently inconvenient or invasive. Muscular contribution to AIS is widely recognized, although it did not translate to clinical routine as yet. Muscle asymmetry has been documented by pathological examinations as well as systemic muscle disorders frequently leading to scoliosis. It has been also reported numerous genetic, metabolic and radiological alterations in patients with AIS, which are linked to muscular and neuromuscular aspects. Therefore, muscles might be considered an attractive and still insufficiently exploited therapeutic target for AIS. Stem cell-based regenerative medicine is rapidly gaining momentum based on the tremendous progress in understanding of developmental biology. It comes also with a toolbox of various stem cells such as satellite cells or mesenchymal stem cells, which could be transplanted; also, the knowledge acquired in research on regenerative medicine can be applied to manipulation of endogenous stem cells to obtain desired therapeutic goals. Importantly, paravertebral muscles are located relatively superficially; therefore, they can be an easy target for minimally invasive approaches to treatment of AIS. It comes in pair with a fast progress in image guidance, which allows for precise delivery of therapeutic agents, including stem cells to various organs such as brain, muscles, and others. Summing up, it seems that there is a link between AIS, muscles, and stem cells, which might be worth of further investigations with a long-term goal of setting foundations for eventual bench-to-bedside translation.

Young at Heart: Combining Strategies to Rejuvenate Endogenous Mechanisms of Cardiac Repair

True cardiac regeneration of the injured heart has been broadly described in lower vertebrates by active replacement of lost cardiomyocytes to functionally and structurally restore the myocardial tissue. On the contrary, following severe injury (i.e., myocardial infarction) the adult mammalian heart is endowed with an impaired reparative response by means of meager wound healing program and detrimental remodeling, which can lead over time to cardiomyopathy and heart failure. Lately, a growing body of basic, translational and clinical studies have supported the therapeutic use of stem cells to provide myocardial regeneration, with the working hypothesis that stem cells delivered to the cardiac tissue could result into new cardiovascular cells to replenish the lost ones. Nevertheless, multiple independent evidences have demonstrated that injected stem cells are more likely to modulate the cardiac tissue via beneficial paracrine effects, which can enhance cardiac repair and reinstate the embryonic program and cell cycle activity of endogenous cardiac stromal cells and resident cardiomyocytes. Therefore, increasing interest has been addressed to the therapeutic profiling of the stem cell-derived secretome (namely the total of cell-secreted soluble factors), with specific attention to cell-released extracellular vesicles, including exosomes, carrying cardioprotective and regenerative RNA molecules. In addition, the use of cardiac decellularized extracellular matrix has been recently suggested as promising biomaterial to develop novel therapeutic strategies for myocardial repair, as either source of molecular cues for regeneration, biological scaffold for cardiac tissue engineering or biomaterial platform for the functional release of factors. In this review, we will specifically address the translational relevance of these two approaches with ad hoc interest in their feasibility to rejuvenate endogenous mechanisms of cardiac repair up to functional regeneration.

The Blood Circulating Rare Cell Population. What is it and What is it Good For?

Blood contains a diverse cell population of low concentration hematopoietic as well as non-hematopoietic cells. The majority of such rare cells may be bone marrow-derived progenitor and stem cells. This paucity of circulating rare cells, in particular in the peripheral circulation, has led many to believe that bone marrow as well as other organ-related cell egress into the circulation is a response to pathological conditions. Little is known about this, though an increasing body of literature can be found suggesting commonness of certain rare cell types in the peripheral blood under physiological conditions. Thus, the isolation and detection of circulating rare cells appears to be merely a technological problem. Knowledge about rare cell types that may circulate the blood stream will help to advance the field of cell-based liquid biopsy by supporting inter-platform comparability, making use of biological correct cutoffs and “mining” new biomarkers and combinations thereof in clinical diagnosis and therapy. Therefore, this review intends to lay ground for a comprehensive analysis of the peripheral blood rare cell population given the necessity to target a broader range of cell types for improved biomarker performance in cell-based liquid biopsy.

Ethical Guiding Principles of "Do No Harm" and the "Intention to Save Lives" in relation to Human Embryonic Stem Cell Research: Finding Common Ground between Religious Views and Principles of Medical Ethics

One of the goals of medicine is to improve well-being, in line with the principle of beneficence (do no harm). Likewise, scientists claim that the goal of human embryonic stem cell (hESC) research is to find treatments for diseases. In hESC research, stem cells are harvested from a 5-day-old embryo. Surplus embryos from infertility treatments or embryos created for the sole purpose of harvesting stem cells are used in the research, and in the process the embryos get destroyed. The use of human embryos for research purpose raises ethical concern. In this context, the religious leaders play the role to be the moral compass and "reality check" to engage with the public. In Malaysia, the Ministry of Health has outlined the Guidelines for Stem Cell Research and Therapy, reflecting on Islamic principles. Since there has not been much focus on the viewpoints of other faiths in Malaysia, this study attempts to (i) explore the ethical guiding principles deliberated by religious leaders from the Buddhist, Hindu and Catholic traditions and (ii) identify if there is a common ground between the mainstream religious views and principles of medical ethics, in relation to hESC research. Eleven religious leaders representing the Buddhist, Hindu and Catholic traditions were interviewed. Interestingly, though reasoning of religious leaders came from different angles, their underlying concerns revolve around the values of "do no harm" and "intention to save lives". These values are also the key principles in medical ethics. The findings are applied to answer the question as to whether religious and medical guiding principles can co-exist and complement in ethical decision-making, without compromising the values.

Melatonin Enhances Mitophagy by Upregulating Expression of Heat Shock 70 kDa Protein 1L in Human Mesenchymal Stem Cells under Oxidative Stress

Human mesenchymal stem cells (hMSCs) are a potent source of cell-based regenerative therapeutics used to treat patients with ischemic disease. However, disease-induced oxidative stress disrupts mitochondrial homeostasis in transplanted hMSCs, resulting in hMSC apoptosis and reducing their efficacy post-transplantation. To address this issue, we evaluated the effects of melatonin on cellular defense mechanisms and mitophagy in hMSCs subjected to oxidative stress. H₂O₂-induced oxidative stress increases the levels of reactive oxygen species and reduces membrane potential in hMSCs, leading to mitochondrial dysfunction and cell death. Oxidative stress also decreases the expression of 70-kDa heat shock protein 1L (HSPA1L), a molecular chaperone that assists in the recruitment of parkin to the autophagosomal mitochondrial membrane. Decreased expression of HSPA1L destabilizes parkin, thereby impairing mitophagy. Our results indicate that treating hMSCs with melatonin significantly inhibited mitochondrial dysfunction induced by oxidative stress, which decreased hMSCs apoptosis. In damaged hMSCs, treatment with melatonin increased the levels of HSPA1L, which bound to parkin. The interaction between HSPA1L and parkin increased membrane potential and levels of oxidative phosphorylation, resulting in enhanced mitophagy. Our results indicate that melatonin increased the expression of HSPA1L, thereby upregulating mitophagy and prolonging cell survival under conditions of oxidative stress. In this study, we have shown that melatonin, a readily available compound, can be used to improve hMSC-based therapies for patients with pathologic conditions involving oxidative stress.

The effect of culture media on large-scale expansion and characteristic of adipose tissue-derived mesenchymal stromal cells

Background

Adipose tissue-derived mesenchymal stromal cells (ASCs) have been shown to exhibit some promising properties of their use in regenerative medicine as advanced therapy medicinal products (ATMP). However, different sources of their origin, methods of isolation, and expansion procedures cause the laboratory and clinical results difficult to compare.

Methods

ASCs were isolated from lipoaspirates and cultured in three different medium formulations: αMEM and DMEM as a basal medium supplemented with 10% of human platelet lysate (hPL) and DMEM supplemented with 20% fetal bovine serum (FBS) and bFGF as a gold standard medium. Subsequently, the impact of culture media on ASCs growth kinetics, their morphology and immunophenotype, ability to differentiate, clonogenic potential, and secretion profile was evaluated.

Results

All cultured ASCs lines showed similar morphology and similar clonogenic potential and have the ability to differentiate into three lines: adipocytes, osteoblasts, and chondroblasts. The immunophenotype of all cultured ASCs was consistent with the guidelines of the International Society for Cell Therapy (ISCT) allowing to define cells as mesenchymal stromal cell (MSC) (≥ 95% CD105, CD73, CD90 and ≤ 2% CD45, CD34, CD14, CD19, HLA-DR). The immunophenotype stabilized after the second passage and did not differ between ASCs cultured in different conditions. The exception was the ASCs grown in the presence of FBS and bFGF, which expressed CD146 antigens. The secretion profile of ASCs cultured in different media was similar. The main secreted cytokine was IL-6, and its level was donor-specific. However, we observed a strong influence of the medium formulation on ASCs growth kinetics. The proliferation rate of ASCs in medium supplemented with hPL was the highest.

Conclusions

Culture media that do not contain animal-derived antigens (xeno-free) can be used to culture cells defined as MSC. Xeno-free medium is a safe alternative for the production of clinical-grade MSC as an advanced therapy medicinal product. Additionally, in such culture conditions, MSC can be easily expanded in accordance with the Good Manufacturing Process (GMP) requirements to a desired amount of cells for clinical applications.

Adipose-Derived Mesenchymal Stem Cells: A Promising Tool in the Treatment of Musculoskeletal Diseases

Chronic musculoskeletal (MSK) pain is one of the most common medical complaints worldwide and musculoskeletal injuries have an enormous social and economical impact. Current pharmacological and surgical treatments aim to relief pain and restore function; however, unsatiscactory outcomes are commonly reported. In order to find an accurate treatment to such pathologies, over the last years, there has been a significantly increasing interest in cellular therapies, such as adipose-derived mesenchymal stem cells (AMSCs). These cells represent a relatively new strategy in regenerative medicine, with many potential applications, especially regarding MSK disorders, and preclinical and clinical studies have demonstrated their efficacy in muscle, tendon, bone and cartilage regeneration. Nevertheless, several worries about their safety and side effects at long-term remain unsolved. This article aims to review the current state of AMSCs therapy in the treatment of several MSK diseases and their clinical applications in veterinary and human medicine.

Preclinical Evaluation of Long-Term Neuroprotective Effects of BDNF-Engineered Mesenchymal Stromal Cells as Intravitreal Therapy for Chronic Retinal Degeneration in Rd6 Mutant Mice

This study aimed to investigate whether the transplantation of genetically engineered bone marrow-derived mesenchymal stromal cells (MSCs) to overexpress brain-derived neurotrophic factor (BDNF) could rescue the chronic degenerative process of slow retinal degeneration in the rd6 (retinal degeneration 6) mouse model and sought to identify the potential underlying mechanisms. Rd6 mice were subjected to the intravitreal injection of lentivirally modified MSC-BDNF or unmodified MSC or saline. In vivo morphology, electrophysiological retinal function (ERG), and the expression of apoptosis-related genes, as well as BDNF and its receptor (TrkB), were assessed in retinas collected at 28 days and three months after transplantation. We observed that cells survived for at least three months after transplantation. MSC-BDNF preferentially integrated into the outer retinal layers and considerably rescued damaged retinal cells, as evaluated by ERG and immunofluorescence staining. Additionally, compared with controls, the therapy with MSC-BDNF was associated with the induction of molecular changes related to anti-apoptotic signaling. In conclusion, BDNF overexpression observed in retinas after MSC-BDNF treatment could enhance the neuroprotective properties of transplanted autologous MSCs alone in the chronically degenerated retina. This research provides evidence for the long-term efficacy of genetically-modified MSC and may represent a strategy for treating various forms of degenerative retinopathies in the future.

Transcriptomes of human mesenchymal cells isolated from the right ventricle and epicardial fat differ strikingly both directly after isolation and long-term culture

Aims

Mesenchymal stromal cells isolated from different tissues are claimed to demonstrate similar therapeutic potential and are often incorrectly named mesenchymal stem cells. However, through comparison of such cells is lacking. This study aimed to compare the transcriptome of mesenchymal cells of the same phenotype isolated from the heart muscle and epicardial fat of the same patient, before and after culture.

Methods and results

Cells were isolated from biopsies of the right ventricle and epicardial fat collected from five patients (three men and two women, mean age 59.4 ± 2.6) who underwent heart transplantation due to ischaemic cardiomyopathy. In both tissues, immunophenotyping revealed three distinct populations: (i)CD31⁻CD45⁻CD90⁺CD34⁺CD146⁻, (ii) CD31⁻CD45⁻CD90⁺CD34⁻CD146⁺, and (iii) CD31⁻CD45⁻CD90⁻CD34⁻CD146⁺, of which only the first one could be grown after sorting. Material for RNA‐seq was collected from these cells before culture (250 cells) and at passage 6 (5000 cells). Transcriptomic analysis revealed that cells of the same phenotype (CD31⁻CD45⁻CD90⁺CD34⁺CD146⁻) upon isolation preferentially clustered according to the tissue of origin, not to the patient from whom they were isolated. Genes up‐regulated in the right ventricle‐derived cells were related to muscle physiology while down‐regulated genes included those encoding proteins with transmembrane signalling receptor activity. After six passages, heart‐derived and fat‐derived cells did not acquire similar transcriptome. Cells isolated from the right ventricle in comparison with their epicardial fat‐derived counterparts demonstrated higher level of transcripts related, among others, to RNA processing and muscle development. The down‐regulated genes were involved in the nucleosome assembly, DNA packaging and replication, and interleukin‐7‐mediated signalling pathway. Cells from epicardial fat demonstrated higher heterogeneity both before and after culture. Cell culture significantly changed gene expression profile within both tissues.

Conclusions

This study is an essential indication that mesenchymal cells isolated from different tissues do not demonstrate similar properties. Phenotypic identification and ease of isolation cannot be considered as a criterion in any therapeutic utilization of such cells.

Chitin Nanoforms Provide Mechanical and Topological Cues to Support Growth of Human Adipose Stem Cells in Chitosan Matrices

The precise role and value of incorporating nanoforms in biologically active matrices for medical applications is not known. In our current work, we incorporate two chitin nanoforms (i.e., nanocrystals or nanofibers) into Genipin-chitosan crosslinked matrices. These materials were studied as 2D films and 3D porous scaffolds to assess their potential as primary support and guidance for stem cells in tissue engineering and regenerative medicine applications. The incorporation of either nanoforms in these 2D and 3D materials reveals significantly better swelling properties and robust mechanical performance in contrast to nanoform-free chitosan matrices. Furthermore, our data shows that these materials, in particular, incorporation of low concentration chitin nanoforms provide specific topological cues to guide the survival, adhesion, and proliferation of human adipose-derived stem cells. These findings demonstrate the potential of Genipin-chitosan crosslinked matrices impregnated with chitin nanoforms as value added materials for stem cell-based biomedical applications.