High passage number of stem cells adversely affects stem cell activation and myocardial protection

Applications of Gene Editing and Nanotechnology in Stem Cell-Based Therapies for Human Diseases

Stem cell research is a dynamic and fast-advancing discipline with great promise for the treatment of diverse human disorders. The incorporation of gene editing technologies, including ZFNs, TALENs, and the CRISPR/Cas system, in conjunction with progress in nanotechnology, is fundamentally transforming stem cell therapy and research. These innovations not only provide a glimmer of optimism for patients and healthcare practitioners but also possess the capacity to radically reshape medical treatment paradigms. Gene editing and nanotechnology synergistically enhance stem cell-based therapies' precision, efficiency, and applicability, offering transformative potential for treating complex diseases and advancing regenerative medicine. Nevertheless, it is important to acknowledge that these technologies also give rise to ethical considerations and possible hazards, such as inadvertent genetic modifications and the development of genetically modified organisms, therefore creating a new age of designer infants. This review emphasizes the crucial significance of gene editing technologies and nanotechnology in the progress of stem cell treatments, particularly for degenerative pathologies and injuries. It emphasizes their capacity to restructure and comprehensively revolutionize medical treatment paradigms, providing fresh hope and optimism for patients and healthcare practitioners.

Exosomes derived from highly scalable and regenerative human progenitor cells promote functional improvement in a rat model of ischemic stroke

Globally, there are 15 million stroke patients each year who have significant neurological deficits. Today, there are no treatments that directly address these deficits. With demographics shifting to an older population, the problem is worsening. Therefore, it is crucial to develop feasible therapeutic treatments for stroke. In this study, we tested exosomes derived from embryonic endothelial progenitor cells (eEPC) to assess their therapeutic efficacy in a rat model of ischemic stroke. Importantly, we have developed purification methods aimed at producing robust and scalable exosomes suitable for manufacturing clinical grade therapeutic exosomes. We characterized exosome cargos including RNA-seq, miRNAs targets, and proteomic mass spectrometry analysis, and we found that eEPC-exosomes were enhanced with angiogenic miRNAs (i.e., miR-126), anti-inflammatory miRNA (i.e., miR-146), and anti-apoptotic miRNAs (i.e., miR-21). The angiogenic activity of diverse eEPC-exosomes sourced from a panel of eEPC production lines was assessed in vitro by live-cell vascular tube formation and scratch wound assays, showing that several eEPC-exosomes promoted the proliferation, tube formation, and migration in endothelial cells. We further applied the exosomes systemically in a rat middle cerebral artery occlusion (MCAO) model of stroke and tested for neurological recovery (mNSS) after injury in ischemic animals. The mNSS scores revealed that recovery of sensorimotor functioning in ischemic MCAO rats increased significantly after intravenous administration of eEPC-exosomes and outpaced recovery obtained through treatment with umbilical cord stem cells. Finally, we investigated the potential mechanism of eEPC-exosomes in mitigating ischemic stroke injury and inflammation by the expression of neuronal, endothelial, and inflammatory markers. Taken together, these data support the finding that eEPCs provide a valuable source of exosomes for developing scalable therapeutic products and therapies for stroke and other ischemic diseases.

Behavioral dynamics of medicinal signaling cells from porcine bone marrow in long-term culture

Medicinal signaling cells (MSC) hold promise for regenerative medicine due to their ability to repair damaged tissues. However, their effectiveness can be affected by how long they are cultured in the lab. This study investigated how passage number influences key properties for regenerative medicine of pig bone marrow MSC. The medicinal signiling cells derived from pig bone marrow (BM-MSC) were cultured in D-MEM High Glucose supplemented with 15% foetal bovine serum until the 25th passage and assessed their growth, viability, ability to differentiate into different cell types (plasticity), and cell cycle activity. Our findings showed that while the cells remained viable until the 25th passage, their ability to grow and differentiate declined after the 5th passage. Additionally, cells in later passages spent more time in a resting phase, suggesting reduced activity. In conclusion, the number of passages is a critical factor for maintaining ideal MSC characteristics. From the 9th passage BM-MSC exhibit decline in proliferation, differentiation potential, and cell cycle activity. Given this, it is possible to suggest that the use of 5th passage cells is the most suitable for therapeutic applications.

Mesenchymal stem cells overexpressing interleukin-10 prevent allergic airway inflammation

BACKGROUNDS

Allergic airway inflammation is prevalent worldwide and imposes a considerable burden on both society and affected individuals. This study aimed to investigate the therapeutic advantages of mesenchymal stem cells (MSCs) overexpressed interleukin-10 (IL-10) for the treatment of allergic airway inflammation, as both IL-10 and MSCs possess immunosuppressive properties.

METHODS

Induced pluripotent stem cell (iPSC)-derived MSCs were engineered to overexpress IL-10 via lentiviral transfection (designated as IL-10-MSCs). MSCs and IL-10-MSCs were administered intravenously to mice with allergic inflammation induced by ovalbumin (OVA), and the features of allergic inflammation including inflammatory cell infiltration, Th cells in the lungs, and T helper 2 cell (Th2) cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. MSCs and IL-10-MSCs were co-cultured with CD4+ T cells from patients with allergic rhinitis (AR), and the levels of Th2 cells and corresponding type 2 cytokines were studied. RNA-sequence was performed to further investigate the potential effects of MSCs and IL-10-MSCs on CD4+ T cells.

RESULTS

Stable IL-10-MSCs were established and characterised by high IL-10 expression. IL-10-MSCs significantly reduced inflammatory cell infiltration and epithelial goblet cell numbers in the lung tissues of mice with allergic airway inflammation. Inflammatory cell and cytokine levels in BALF also decreased after the administration of IL-10-MSCs. Moreover, IL-10-MSCs showed a stronger capacity to inhibit the levels of Th2 after co-cultured with CD4+ T cells from patients with AR. Furthermore, we elucidated lower levels of IL-5 and IL-13 in IL-10-MSCs treated CD4+ T cells, and blockade of IL-10 significantly reversed the inhibitory effects of IL-10-MSCs. We also reported the mRNA profiles of CD4+ T cells treated with IL-10-MSCs and MSCs, in which IL-10 played an important role.

CONCLUSION

IL-10-MSCs showed positive effects in the treatment of allergic airway inflammation, providing solid support for the use of genetically engineered MSCs as a potential novel therapy for allergic airway inflammation.

Towards the Standardization of Mesenchymal Stem Cell Secretome-Derived Product Manufacturing for Tissue Regeneration

Mesenchymal stem cell secretome or conditioned medium (MSC-CM) is a combination of biomolecules and growth factors in cell culture growth medium, secreted by mesenchymal stem cells (MSCs), and the starting point of several derived products. MSC-CM and its derivatives could be applied after injuries and could mediate most of the beneficial regenerative effects of MSCs without the possible side effects of using MSCs themselves. However, before the clinical application of these promising biopharmaceuticals, several issues such as manufacturing protocols and quality control must be addressed. This review aims to underline the influence of the procedure for conditioned medium production on the quality of the secretome and its derivatives and highlights the questions considering cell sources and donors, cell expansion, cell passage number and confluency, conditioning period, cell culture medium, microenvironment cues, and secretome-derived product purification. A high degree of variability in MSC secretomes is revealed based on these parameters, confirming the need to standardize and optimize protocols. Understanding how bioprocessing and manufacturing conditions interact to determine the quantity, quality, and profile of MSC-CM is essential to the development of good manufacturing practice (GMP)-compliant procedures suitable for replacing mesenchymal stem cells in regenerative medicine.

Umbilical cord-derived mesenchymal stromal cells preserve endogenous insulin production in type 1 diabetes: a Phase I/II randomised double-blind placebo-controlled trial

AIM/HYPOTHESIS

This study aimed to investigate the safety and efficacy of treatment with allogeneic Wharton's jelly-derived mesenchymal stromal cells (MSCs) in recent-onset type 1 diabetes.

METHODS

A combined Phase I/II trial, composed of a dose escalation followed by a randomised double-blind placebo-controlled study in parallel design, was performed in which treatment with allogeneic MSCs produced as an advanced therapy medicinal product (ProTrans) was compared with placebo in adults with newly diagnosed type 1 diabetes. Inclusion criteria were a diagnosis of type 1 diabetes <2 years before enrolment, age 18-40 years and a fasting plasma C-peptide concentration >0.12 nmol/l. Randomisation was performed with a web-based randomisation system, with a randomisation code created prior to the start of the study. The randomisation was made in blocks, with participants randomised to ProTrans or placebo treatment. Randomisation envelopes were kept at the clinic in a locked room, with study staff opening the envelopes at the baseline visits. All participants and study personnel were blinded to group assignment. The study was conducted at Karolinska University Hospital, Stockholm, Sweden.

RESULTS

Three participants were included in each dose cohort during the first part of the study. Fifteen participants were randomised in the second part of the study, with ten participants assigned to ProTrans treatment and five to placebo. All participants were analysed for the primary and secondary outcomes. No serious adverse events related to treatment were observed and, overall, few adverse events (mainly mild upper respiratory tract infections) were reported in the active treatment and placebo arms. The primary efficacy endpoint was defined as Δ-change in C-peptide AUC for a mixed meal tolerance test at 1 year following ProTrans/placebo infusion compared with baseline performance prior to treatment. C-peptide levels in placebo-treated individuals declined by 47%, whereas those in ProTrans-treated individuals declined by only 10% (p<0.05). Similarly, insulin requirements increased in placebo-treated individuals by a median of 10 U/day, whereas insulin needs of ProTrans-treated individuals did not change over the follow-up period of 12 months (p<0.05).

CONCLUSIONS/INTERPRETATION

This study suggests that allogeneic Wharton's jelly-derived MSCs (ProTrans) is a safe treatment for recent-onset type 1 diabetes, with the potential to preserve beta cell function.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03406585 FUNDING: The sponsor of the clinical trial is NextCell Pharma AB, Stockholm, Sweden.

Local, systemic and immunologic safety comparison between xenogeneic equine umbilical cord mesenchymal stem cells, allogeneic canine adipose mesenchymal stem cells and placebo: a randomized controlled trial

Mesenchymal stem cells are multipotent cells with a wide range of therapeutic applications, including, among others, tissue regeneration. This work aims to test the safety (EUC-MSC) of intra-articular administration of equine umbilical cord mesenchymal stem cells in young healthy dogs under field conditions following single and repeated administration. This was compared with the safety profile of allogenic canine adipose derived mesenchymal stem cells (CAD-MSC) and placebo in order to define the safety of xenogeneic use of mesenchymal stem cells when administered intra-articular. Twenty-four police working dogs were randomized in three groups in a proportion 1:1:1. EUC-MSCs and CAD-MSCs were obtained from healthy donors and were manufactured following company SOPs and under GMP and GMP-like conditions, respectively, and compliant all necessary controls to ensure the quality of the treatment. The safety of the treatment was evaluated locally, systemically and immunologically. For this purpose, an orthopedic examination and Glasgow test for the assessment of pain in the infiltrated joint, blood tests, clinical examination and analysis of the humoral and cellular response to treatment were performed. No adverse events were detected following single and repeated MSC administration despite both equine and canine MSC generate antibody titres in the dogs. The intra-articular administration of equine umbilical cord mesenchymal stem cells in dogs has demonstrated to be safe.

Bioreactor Expansion Reconfigures Metabolism and Extracellular Vesicle Biogenesis of Human Adipose-derived Stem Cells In Vitro

Human mesenchymal stem cells (hMSCs), including human adipose tissue-derived stem cells (hASCs), as well as the secreted extracellular vesicles (EVs), are promising therapeutics in treating inflammatory and neural degenerative diseases. However, prolonged expansion can lead to cellular senescence characterized by a gradual loss of self-renewal ability while altering secretome composition and EV generation. Additionally, hMSCs are highly sensitive to biophysical microenvironment in bioreactor systems utilized in scaling production. In this study, hASCs grown on Plastic Plus or Synthemax II microcarriers in a spinner flask bioreactor (SFB) system were compared to traditional 2D culture. The SFB microenvironment was found to increase the expression of genes associated with hASC stemness, nicotinamide adenine dinucleotide (NAD+) metabolism, glycolysis, and the pentose phosphate pathway as well as alter cytokine secretion (e.g., PGE2 and CXCL10). Elevated reactive oxidative species levels in hASCs of SFB culture were observed without increasing rates of cellular senescence. Expression levels of Sirtuins responsible for preventing cellular senescence through anti-oxidant and DNA repair mechanisms were also elevated in SFB cultures. In particular, the EV biogenesis genes were significantly upregulated (3-10 fold) and the EV production increased 40% per cell in SFB cultures of hASCs. This study provides advanced understanding of hASC sensitivity to the bioreactor microenvironment for EV production and bio-manufacturing towards the applications in treating inflammatory and neural degenerative diseases.

Paracrine Factors Released by Stem Cells of Mesenchymal Origin and their Effects in Cardiovascular Disease: A Systematic Review of Pre-clinical Studies

Mesenchymal stem cell (MSC) therapy has gained significant traction in the context of cardiovascular repair, and have been proposed to exert their regenerative effects via the secretion of paracrine factors. In this systematic review, we examined the literature and consolidated available evidence for the "paracrine hypothesis". Two Ovid SP databases were searched using a strategy encompassing paracrine mediated MSC therapy in the context of ischemic heart disease. This yielded 86 articles which met the selection criteria for inclusion in this study. We found that the MSCs utilized in these articles were primarily derived from bone marrow, cardiac tissue, and adipose tissue. We identified 234 individual protective factors across these studies, including VEGF, HGF, and FGF2; which are proposed to exert their effects in a paracrine manner. The data collated in this systematic review identifies secreted paracrine factors that could decrease apoptosis, and increase angiogenesis, cell proliferation, and cell viability. These included studies have also demonstrated that the administration of MSCs and indirectly, their secreted factors can reduce infarct size, and improve left ventricular ejection fraction, contractility, compliance, and vessel density. Furthering our understanding of the way these factors mediate repair could lead to the identification of therapeutic targets for cardiac regeneration.

Biological activity reduction and mitochondrial and lysosomal dysfunction of mesenchymal stem cells aging in vitro

BACKGROUND

Mesenchymal stem cells (MSCs) have been extensively used for the treatment of various diseases in preclinical and clinical trials. In vitro propagation is needed to attain enough cells for clinical use. However, cell aging and viability reduction caused by long-time culture have not been thoroughly investigated, especially for the function of mitochondria and lysosomes. Therefore, this study was designed to detect mitochondrial and lysosomal activity, morphological and functional changes in human umbilical cord MSCs (UMSCs) after long-time culture.

METHODS

First, we examined cell activities, including proliferation and immigration ability, differentiation potential, and immunosuppressive capacity of UMSCs at an early and late passages as P4 (named UMSC-P4) and P9 (named UMSC-P9), respectively. Then, we compared the mitochondrial morphology of UMSC-P4 and UMSC-P9 using the electronic microscope and MitoTracker Red dyes. Furthermore, we investigated mitochondrial function, including mitochondrial membrane potential, antioxidative ability, apoptosis, and ferroptosis detected by respective probe. Cell energy metabolism was tested by mass spectrometry. In addition, we compared the lysosomal morphology of UMSC-P4 and UMSC-P9 by electronic microscope and lysoTracker Red dyes. Finally, the transcriptome sequence was performed to analyze the total gene expression of these cells.

RESULTS

It was found that UMSC-P9 exhibited a reduced biological activity and showed an impaired mitochondrial morphology with disordered structure,  reduced mitochondrial crista, and mitochondrial fragments. They also displayed decreased mitochondrial membrane potential, antioxidative ability, tricarboxylic acid cycle activity and energy production. At the same time, apoptosis and ferroptosis were increased. In addition, UMSC-P9, relative to UMSC-P4, showed undegraded materials in their lysosomes, the enhancement in lysosomal membrane permeability, the reduction in autophagy and phagocytosis. Moreover, transcriptome sequence analysis also revealed a reduction of cell function, metabolism, mitochondrial biogenesis, DNA replication and repair, and an increase of gene expression related to cell senescence, cancer, diseases, and infection in UMSC-P9.

CONCLUSION

This study indicates that in vitro long-time culturing of MSCs can cause mitochondrial and lysosomal dysfunction, probably contributing to the decline of cell activity and cell aging. Therefore, the morphology and function of mitochondria and lysosomes can be regarded as two important parameters to monitor cell viability, and they can also serve as two important indicators for optimizing in vitro culture conditions.

A Brief Overview of Global Trends in MSC-Based Cell Therapy

Human mesenchymal stem cells (MSCs), also known as mesenchymal stromal cells or medicinal signaling cells, are important adult stem cells for regenerative medicine, largely due to their regenerative characteristics such as self-renewal, secretion of trophic factors, and the capability of inducing mesenchymal cell lineages. MSCs also possess homing and trophic properties modulating immune system, influencing microenvironment around damaged tissues and enhancing tissue repair, thus offering a broad perspective in cell-based therapies. Therefore, it is not surprising that MSCs have been the broadly used adult stem cells in clinical trials. To gain better insights into the current applications of MSCs in clinical applications, we perform a comprehensive review of reported data of MSCs clinical trials conducted globally. We summarize the biological effects and mechanisms of action of MSCs, elucidating recent clinical trials phases and findings, highlighting therapeutic effects of MSCs in several representative diseases, including neurological, musculoskeletal diseases and most recent Coronavirus infectious disease. Finally, we also highlight the challenges faced by many clinical trials and propose potential solutions to streamline the use of MSCs in routine clinical applications and regenerative medicine.

Protease Activated Receptors: A Pathway to Boosting Mesenchymal Stromal Cell Therapeutic Efficacy in Acute Respiratory Distress Syndrome?

Acute Respiratory Distress Syndrome is the most common cause of respiratory failure among critically ill patients, and its importance has been heightened during the COVID-19 pandemic. Even with the best supportive care, the mortality rate in the most severe cases is 40–50%, and the only pharmacological agent shown to be of possible benefit has been steroids. Mesenchymal stromal cells (MSCs) have been tested in several pre-clinical models of lung injury and been found to have significant therapeutic benefit related to: (a) potent immunomodulation; (b) secretion of epithelial and endothelial growth factors; and (c) augmentation of host defense to infection. Initial translational efforts have shown signs of promise, but the results have not yielded the anticipated outcomes. One potential reason is the relatively low survival of MSCs in inflammatory conditions as shown in several studies. Therefore, strategies to boost the survival of MSCs are needed to enhance their therapeutic effect. Protease-activated receptors (PARs) may represent one such possibility as they are G-protein coupled receptors expressed by MSCs and control several facets of cell behavior. This review summarizes some of the existing literature about PARs and MSCs and presents possible future areas of investigation in order to develop potential, PAR-modified MSCs with enhanced therapeutic efficiency.

Applications of genome editing tools in stem cells towards regenerative medicine: An update

Precise and site specific genome editing through application of emerging and modern gene engineering techniques, namely zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) have swiftly progressed the application and use of the stem cell technology in the sphere of in-vitro disease modelling and regenerative medicine. Genome editing tools facilitate the manipulating of any gene in various types of cells with target specific nucleases. These tools aid in elucidating the genetics and etiology behind different diseases and have immense promise as novel therapeutics for correcting the genetic mutations, make alterations and cure diseases permanently that are not responding and resistant to traditional therapies. These genome engineering tools have evolved in the field of biomedical research and have also shown to have a significant improvement in clinical trials. However, their widespread use in research revealed potential safety issues, which need to be addressed before implementing such techniques in clinical purposes. Significant and valiant attempts are being made in order to surpass those hurdles. The current review outlines the advancements of several genome engineering tools and describes suitable strategies for their application towards regenerative medicine.

Human Adipose-Derived Mesenchymal Stromal Cells Exhibit High HLA-DR Levels and Altered Cellular Characteristics under a Xeno-free and Serum-free Condition

Background

We have observed an increased expression of negative markers in some clinical-grade, xeno- and serum-free cultured adipose-derived mesenchymal stem/stromal cell (ADMSC) samples. It gave rise to concern that xeno- and serum-free conditions might have unexpected effects on human ADMSCs. This study aims to test this hypothesis for two xeno- and serum-free media, PowerStem MSC1 media (PS) and StemMACS MSC Expansion Media (SM), that support the in vitro expansion of ADMSCs.

Methods

We investigated the expression of negative markers in 42 clinical-grade ADMSC samples expanded in PS. Next, we cultured ADMSCs from seven donors in PS and SM and examined their growth and colony-forming ability, surface marker expression, differentiation, cell cycle and senescence, as well as genetic stability of two passages representing an early and late passage for therapeutic MSCs.

Results

15 of 42 clinical-grade PS-expanded ADMSC samples showed an increased expression of negative markers ranging from 2.73% to 34.24%, which positively correlated with the age of donors. This rise of negative markers was related to an upregulation of Human Leukocyte Antigen – DR (HLA-DR). In addition, the PS-cultured cells presented decreased growth ability, lower frequencies of cells in S/G2/M phases, and increased ß-galactosidase activity in passage 7 suggesting their senescent feature compared to those grown in SM. Although MSCs of both PS and SM cultures were capable of multilineage differentiation, the PS-cultured cells demonstrated chromosomal abnormalities in passage 7 compared to the normal karyotype of their SM counterparts.

Conclusions

These findings suggest that the SM media is more suitable for the expansion of therapeutic ADMSCs than PS. The study also hints a change of ADMSC features at more advanced passages and with increased donor’s age. Thus, it emphasizes the necessity to cover these aspects in the quality control of therapeutic MSC products.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12015-021-10242-7.

From Transcriptome to Behavior: Intranasal Injection of Late Passage Human Olfactory Stem Cells Displays Potential in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, which is caused by the loss of dopaminergic (DAergic) neurons. Thus, cell replacement therapy (CRT) might be regarded as an alternative therapy to effectively treat motor functional defects in PD patients. Human olfactory ectomesenchymal stem cells (OE-MSCs) are a novel type of mesenchymal stem cells (MSCs) with a strong tendency to differentiate into DAergic neurons. However, there are various barriers to successful CRT including the proliferation capacity of stem cells at higher passage numbers as well as the route of stem cell delivery. In this regard, we aimed to explore the efficacy of late passage OE-MSC administration through the intranasal (IN) route in PD rat models. Herein, the proliferation capacity of OE-MSCs was compared at early and late passage numbers; then, the results were validated via RNA sequencing analysis. Subsequently, the efficacy of IN injection of late passage OE-MSC in PD models was evaluated. The results manifested the absence of noticeable differences in proliferation capacity and signaling pathways in OE-MSCs at early and late passage numbers. Moreover, it was found that the IN administration of OE-MSCs with a high passage number substantially increased the levels of DAergic markers and improved the motor function in rat models of PD. Overall, our findings suggested that OE-MSCs with a high passage number are a promising CRT candidate due to their fundamental potential to provide a large number of cells with an enormous proliferation capacity. Moreover, they exhibit the high efficiency of IN administration as a noninvasive route of late-passage OE-MSC delivery for CRT, particularly for PD.

NSAIDs inhibit bone healing through the downregulation of TGF-β3 expression during endochondral ossification

INTRODUCTION & AIMS

Non Steroidal Anti-Inflammatory drugs (NSAIDs) are potent inhibitors of post-traumatic pain. Several studies have highlighted that NSAIDs could exert a negative effect on bone healing process possibly by down-regulating chondrogenesis and endochondral ossification. The aim of the study is to explore the potential mechanism though which NSAIDs can affect chondrogenesis. M&M: Trabecular bone from the fracture site was isolated from 10 patients suffering from long bone fractures. Mesenchymal Stem Cells (MSCs) were isolated following collagenase digestion and functional assays to assess the effect of diclofenac sodium on chondrogenesis were performed. Gene expression analysis of 84 key molecules was performed.

RESULTS

Diclofenac sodium inhibits chondrogenic differentiation and induces a strong inhibition of prostaglandin E-2 (PGE-2) production during chondrogenic differentiation. Replenishment of PGE-2 did not reverse this negative effect. Chondrogenic inhibition is similar in cells treated only for the first week of chondrogenic differentiation or continuously for 3 weeks. Gene analysis shows a strong downregulation of TGF-β3 and FGF-1 while TNF was upregulated.

CONCLUSION

NSAIDs seem to affect the transition phase of mesenchymal stem cells towards functional chondrocytes. This effect is unrelated to the endogenous production of PGE-2. The downregulation of the expression of key molecules like TGF-β3 seem to be the underlying mechanism.

Recent Advances in Injectable Dual Crosslinking Hydrogels for Biomedical Applications

Injectable dual crosslinking hydrogels hold great promise to improve therapeutic efficacy in minimally invasive surgery. Compared with prefabricated hydrogels, injectable hydrogels can be implanted more accurately into deeply enclosed sites and repair irregularly shaped lesions, showing great applicable potential. Here, the current fabrication considerations of injectable dual crosslinking hydrogels are reviewed. Besides, the progress of the hydrogels used in corresponding applications and emerging challenges are discussed, with detailed emphasis in the fields of bone and cartilage regeneration, wound dressings, sensors and other less mentioned applications for their more hopeful employments in clinic. It is envisioned that the further development of the injectable dual crosslinking hydrogels will catalyze their innovation and transformation in the biomedical field.

Emerging Cell-Based Therapies in Chronic Lung Diseases: What About Asthma?

Asthma is a widespread disease characterized by chronic airway inflammation. It causes substantial disability, impaired quality of life, and avoidable deaths around the world. The main treatment for asthmatic patients is the administration of corticosteroids, which improves the quality of life; however, prolonged use of corticosteroids interferes with extracellular matrix elements. Therefore, cell-based therapies are emerging as a novel therapeutic contribution to tissue regeneration for lung diseases. This study aimed to summarize the advancements in cell therapy involving mesenchymal stromal cells, extracellular vesicles, and immune cells such as T-cells in asthma. Our findings provide evidence that the use of mesenchymal stem cells, their derivatives, and immune cells such as T-cells are an initial milestone to understand how emergent cell-based therapies are effective to face the challenges in the development, progression, and management of asthma, thus improving the quality of life.

Human Mesenchymal Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI), as a devastating and life-altering neurological disorder, is one of the most serious health issues. Currently, the management of acute SCI includes pharmacotherapy and surgical decompression. Both the approaches have been observed to have adverse physiological effects on SCI patients. Therefore, novel therapeutic targets for the management of SCI are urgently required for developing cell-based therapies. Multipotent stem cells, as a novel strategy for the treatment of tissue injury, may provide an effective therapeutic option against many neurological disorders. Mesenchymal stem cells (MSCs) or multipotent stromal cells can typically self-renew and generate various cell types. These cells are often isolated from bone marrow (BM-MSCs), adipose tissues (AD-MSCs), umbilical cord blood (UCB-MSCs), and placenta (PMSCs). MSCs have remarkable potential for the development of regenerative therapies in animal models and humans with SCI. Herein, we summarize the therapeutic potential of human MSCs in the treatment of SCI.

Genomic Engineering in Human Hematopoietic Stem Cells: Hype or Hope?

Many gene editing techniques are developed and tested, yet, most of these are optimized for transformed cell lines, which differ from their primary cell counterparts in terms of transfectability, cell death propensity, differentiation capability, and chromatin accessibility to gene editing tools. Researchers are working to overcome the challenges associated with gene editing of primary cells, namely, at the level of improving the gene editing tool components, e.g., the use of modified single guide RNAs, more efficient delivery of Cas9 and RNA in the ribonucleoprotein of these cells. Despite these efforts, the low efficiency of proper gene editing in true primary cells is an obstacle that needs to be overcome in order to generate sufficiently high numbers of corrected cells for therapeutic use. In addition, many of the therapeutic candidate genes for gene editing are expressed in more mature blood cell lineages but not in the hematopoietic stem cells (HSCs), where they are tightly packed in heterochromatin, making them less accessible to gene editing enzymes. Bringing HSCs in proliferation is sometimes seen as a solution to overcome lack of chromatin access, but the induction of proliferation in HSCs often is associated with loss of stemness. The documented occurrences of off-target effects and, importantly, on-target side effects also raise important safety issues. In conclusion, many obstacles still remain to be overcome before gene editing in HSCs for gene correction purposes can be applied clinically. In this review, in a perspective way, we will discuss the challenges of researching and developing a novel genetic engineering therapy for monogenic blood and immune system disorders.

Human umbilical cord multipotent mesenchymal stromal cells alleviate acute ischemia-reperfusion injury of spermatogenic cells via reducing inflammatory response and oxidative stress

BACKGROUND

This study was designed to determine the effect of human umbilical cord multipotent mesenchymal stromal cells (hUC-MSC) on acute ischemia/reperfusion (I/R) injury of spermatogenic cells.

METHOD

The testicular I/R rat model was established through 720° torsion for 1 h. hUC-MSC were intravenously injected 10 min before detorsion. Injury severity of spermatogenic cells was estimated by Johnsen's score. The proliferating of recipient spermatogonia was measured by the immunostaining of antibodies against Ki67, and all germ cells were detected with DDX4 antibody. And recipient spermatogenesis was assessed by staining spermatozoa with lectin PNA. The levels of inflammatory factors were measured by real-time PCR. And the Selectin-E expression, neutrophil infiltration in the testes was detected by immunostaining. Germ cells apoptosis was tested by TUNEL assay and western blot. Furthermore, the oxidative stress was tested by reactive oxidative species (ROS) levels. In vitro, the condition medium (CM) of hUC-MSC was used to culture human umbilical vein endothelial cells (HUVECs), so as to assess the paracrine effect of hUC-MSC on HUVECs. The protein chip was used to measure the relative concentration of the secretory proteins in the CM of hUC-MSC.

RESULT

hUC-MSC greatly alleviated the testicular injury induced by testis I/R. The levels of proinflammatory factors were downregulated by hUC-MSC in vivo and in vitro. Neutrophil infiltration, ROS, and germ cell apoptosis in testicular tissues were greatly reduced in the group of hUC-MSC. Paracrine factors secreted by hUC-MSC including growth factors, cytokines, and anti-inflammatory cytokine were rich.

CONCLUSION

This study demonstrated that intravenously injected hUC-MSC could protect the spermatogenic cells against I/R injury by reducing the inflammatory response, apoptosis, and acute oxidative injury. Paracrine mechanism of hUC-MSC may contribute to the protection of spermatogenic cells against I/R injury. Therefore, the present study provides a method for clinical treatment of attenuate I/R injury of spermatogenic cells.

Basic fibroblast growth factor enhances proliferation and hepatocyte growth factor expression of feline mesenchymal stem cells

Introduction

The objective of this study is to evaluate the effect of basic fibroblast growth factor (bFGF) on the proliferation and secretion activity of feline adipose-derived mesenchymal stem cells (MSC).

Methods

Feline MSC isolated from the subcutaneous adipose tissue of cats were cultured with or without bFGF.

Results

The bFGF addition enhanced the proliferation of feline MSC to a significant great extent compared with that without bFGF, although the cell proliferation tended to increase with the bFGF concentration. In addition, adipogenic and osteogenic staining assay demonstrated that the bFGF addition allowed MSC to maintain the differentiation ability even after the proliferation. Moreover, no change in the surface markers of MSC was observed between the cultures with or without bFGF. A quantitative RT-PCR assay revealed that the HGF and TSG-6 expression significantly increased by the bFGF addition. The highest mRNA expression of MMP-2 was observed for cells cultured in 1000 ng/ml bFGF concentration.

Conclusions

The culture with bFGF is a promising way to enhance the proliferation, and HGF secretion ability of MSC as well as maintain their differentiation ability and immunophenotype nature.

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Feline adipose-derived mesenchymal stem cells (MSC) was cultured with or without the basic fibroblast growth factor (bFGF).

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The bFGF enhanced the proliferation and increased the mRNA expression of HGF, TSG-6, and MMP-2.

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The bFGF addition was not influenced to the differentiation ability and cell surface marker of MSC.

Nrf2 modulates immunosuppressive ability and cellular senescence of human umbilical cord mesenchymal stem cells

In the application of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) as clinical therapeutics, long term cells ex vivo expansion results in decline in their function. It has been widely concerned that cellular senescence is associated with UC-MSCs immunomodulatory ability. In this study, we evaluated the effects of consecutive passages on cellular senescence and the immunomodulatory abilities of UC-MSCs. Long term-cultured UC-MSCs showed decreased proliferation, senescence phenotypes and impaired immunosuppressive effects on PHA induced peripheral blood mononuclear cell (PBMC) proliferation. We found that Nrf2, a transcription factor that responds to oxidative stress, that showed decreased expression in long term-cultured UC-MSCs, and the further knock-down of Nrf2 in UC-MSCs induced premature senescence, decreased proliferation ability and immunosuppressive abilities. Furthermore, the protein expression of IDO-1 were decreased in response to the downregulation of Nrf2 in UC-MSCs, suggesting that Nrf2 regulates the immunosuppressive properties of UC-MSCs via Nrf2-mediated IDO-1 expression. In conclusion, our results demonstrate that Nrf2 plays a key role in the regulation of the immunosuppressive properties of UC-MSCs, and we suggest that these findings might provide a strategy to enhance the functionality of UC-MSCs for use in therapeutic applications.

Decreased immunomodulatory and secretory capability of aging human umbilical cord mesenchymal stem cells in vitro

Mesenchymal stem cell therapy has drawn much attention as a promising therapeutic option for the treatment of different diseases. Due to insufficient cell population derived from freshly isolated tissues, in vitro propagation is required prior to clinical use. However, reduced cell viability of aging mesenchymal stem cell (MSCs) with repeated propagations has yet not be fully investigated, especially for the biological characteristics of immunoregulatory ability and paracrine factors. In this study, we compared the biological properties of human umbilical cord-MSCs (hUC-MSCs) at different passages, especially for immunomodulatory ability and secretions. Our results showed that hUC-MSCs at early passage (P2) and late passage (P8) exhibited similar morphology and surface marker expression, but hUC-MSCs at P8 displayed reduced proliferation and differentiation potential, immunoregulatory and secretory ability. In particular, hUC-MSCs at P2 and P5 could significantly suppress the population of proinflammatory Th1 and Th17 cell subsets and upregulate Treg cells, but not with hUC-MSCs at P8. For paracrine mechanism, higher level of secretions such as growth factors, cell adhesions, anti-inflammatory factors of hUC-MSCs were observed at P2 and P5 compared to that at P8. Therefore, it is essential to verify and validate the biological characteristics of hUC-MSCs that possess a good vitality before they are released for clinical use. Altogether, this study provides a rationale and two important parameters for how to select appropriate passage and vitality of MSCs for cell therapy.

Ethanol-mediated compaction and cross-linking enhance mechanical properties and degradation resistance while maintaining cytocompatibility of a nucleus pulposus scaffold

Intervertebral disc degeneration is a complex, cell-mediated process originating in the nucleus pulposus (NP) and is associated with extracellular matrix catabolism leading to disc height loss and impaired spine kinematics. Previously, we developed an acellular bovine NP (ABNP) for NP replacement that emulated human NP matrix composition and supported cell seeding; however, its mechanical properties were lower than those reported for human NP. To address this, we investigated ethanol-mediated compaction and cross-linking to enhance the ABNP's dynamic mechanical properties and degradation resistance while maintaining its cytocompatibility. First, volumetric and mechanical effects of compaction only were confirmed by evaluating scaffolds after various immersion times in buffered 28% ethanol. It was found that compaction reached equilibrium at ~30% compaction after 45 min, and dynamic mechanical properties significantly increased 2-6× after 120 min of submersion. This was incorporated into a cross-linking treatment, through which scaffolds were subjected to 120 min precompaction in buffered 28% ethanol prior to carbodiimide cross-linking. Their dynamic mechanical properties were evaluated before and after accelerated degradation by ADAMTS-5 or MMP-13. Cytocompatibility was determined by seeding stem cells onto scaffolds and evaluating viability through metabolic activity and fluorescent staining. Compacted and cross-linked scaffolds showed significant increases in DMA properties without detrimentally altering their cytocompatibility, and these mechanical gains were maintained following enzymatic exposure. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2488-2499, 2019.

Enhancing the Wound Healing Effect of Conditioned Medium Collected from Mesenchymal Stem Cells with High Passage Number Using Bioreducible Nanoparticles

Injecting human mesenchymal stem cells (hMSCs) at wound sites is known to have a therapeutic effect; however, hMSCs have several limitations, such as low viability and poor engraftment after injection, as well as a potential risk of oncogenesis. The use of a conditioned medium (CM) was suggested as an alternative method for treating various wounds instead of direct hMSC administration. In addition to not having the adverse effects associated with hMSCs, a CM can be easily mass produced and can be stored for long-term, thereby making it useful for clinical applications. In general, a CM is collected from hMSCs with low passage number; whereas, the hMSCs with high passage number are usually discarded because of their low therapeutic efficacy as a result of reduced angiogenic factor secretion. Herein, we used a CM collected from high passage number (passage 12, P12) hMSCs treated with gold-iron nanoparticles (AuFe NPs). Our AuFe NPs were designed to release the iron ion intracellularly via endocytosis. Endosomes with low pH can dissolve iron from AuFe NPs, and thus, the intracellularly released iron ions up-regulate the hypoxia-inducible factor 1α and vascular endothelial growth factor (VEGF) expression. Through this mechanism, AuFe NPs improve the amount of VEGF expression from P12 hMSCs so that it is comparable to the amount of VEGF expression from low passage number (passage 6, P6), without treatment. Furthermore, we injected the CM retrieved from P12 MSCs treated with AuFe NPs in the mouse skin wound model (AuFe P12 group). AuFe P12 group revealed significantly enhanced angiogenesis in the mouse skin wound model compared to the high passage hMSC CM-injected group. Moreover, the result from the AuFe P12 group was similar to that of the low passage hMSC CM-injected group. Both the AuFe P12 group and low passage hMSC CM-injected group presented significantly enhanced re-epithelization, angiogenesis, and tissue remodeling compared to the high passage hMSC CM-injected group. This study reveals a new strategy for tissue regeneration based on CM injection without considering the high cell passage count.

Mesenchymal stem cells derived from induced pluripotent stem cells play a key role in immunomodulation during cardiopulmonary resuscitation

BACKGROUND/AIMS

Previous in vitro experiments have demonstrated the immunomodulatory functions of mesenchymal stem cells derived from induced pluripotent stem cells (iPSC-MSCs) in brain injury. We have tried to further understand these functions by investigating the neuroprotective effects of iPSC-MSCs in a rat model of cardiac arrest (CA).

METHODS

CA was induced in adult Sprague-Dawley rats by transcutaneous electrical epicardium stimulation. The rats were divided into four groups. In a separate cohort of sham operation animals, iPSC-MSCs or PBS was infused via the femoral vein after restoration of spontaneous circulation. Survival was evaluated every 2 h until 24 h after CA. Markers of classically activated macrophages (M1) and alternatively activated (M2) macrophages were assessed by qPCR and western blot analysis, and the gene expression profiles of the macrophages were studied in order to identify differentially expressed proteins.

RESULTS

The 24-h survival rate was significantly different between the CPR group and iPSC-MSC group (P = 0.033). Additionally, a significant number of mRNAs were differentially expressed between the iPSC-MSC and PBS group. Compared with the sham operation group, both M1 (27/29) and M2 (2/29) mRNAs showed a significant increase in expression in the CPR group, while only M2 (22) mRNAs showed a significant increase in expression in the iPSC-MSC group. Western blotting analysis showed that the expression of Arg-1 and CD14 (M2 macrophage markers) was increased in the iPSC-MSC group (P < 0.05), while CD86 and iNOS (M1 macrophage markers) expression was increased in the CPR group (P < 0.05).

CONCLUSION

IPSC-MSCs, which play a key role in immunomodulation, downregulate the level of M1 macrophages and upregulate the level of M2 macrophages after CA.

Substance P improves MSC-mediated RPE regeneration by modulating PDGF-BB

Stem cells have regenerative potentials that can be used for the treatment of critical and incurable diseases. Age-related macular degeneration (ARMD) and diabetic retinopathy are one of the most severe retinal disorders, which are mostly attributed to impairment of retinal pigmented epithelium (RPE). Thus, restoration of RPE is the main therapeutic approach to prevent the development of ocular diseases, such as ARMD. In this study, we have investigated the role of substance P (SP) on bone marrow mesenchymal stem cell (MSC)-mediated RPE regeneration in vitro. The MSCs were primed with SP followed by the addition of conditioned medium (MSC^SP-CM) to RPE. The effects of MSC^SP-CM on RPE activity was evaluated by assessing viability, proliferation rate, and migration of RPE. Ex vivo long-term culture led to altered cellular characteristics of MSCs by weakening cell viability, cytokine secretion, and differentiation potential. The conditioned medium of early passage MSC (E-MSC^CM) enhanced the RPE viability and migration, whereas the late passage MSC (L-MSC^CM) hardly influenced the RPE activity. SP priming, however, facilitated the inductive effects of MSC, and SP effect was more distinct in the late passage than in the early passage. Moreover, it was revealed that SP could exert its effects by modulating PDGF-BB secretion in the MSCs. Taken together, these results suggested that SP could restore the therapeutic effects of MSCs on retinal diseases by elevating their proliferative and paracrine activities through PDGF-PDGFR signaling in ex vivo culture.

A comprehensive characterisation of large-scale expanded human bone marrow and umbilical cord mesenchymal stem cells

BACKGROUND

The manufacture of mesenchymal stem/stromal cells (MSCs) for clinical use needs to be cost effective, safe and scaled up. Current methods of expansion on tissue culture plastic are labour-intensive and involve several 'open' procedures. We have used the closed Quantum® hollow fibre bioreactor to expand four cultures each of MSCs derived from bone marrow (BM) and, for the first time, umbilical cords (UCs) and assessed extensive characterisation profiles for each, compared to parallel cultures grown on tissue culture plastic.

METHODS

Bone marrow aspirate was directly loaded into the Quantum®, and cells were harvested and characterised at passage (P) 0. Bone marrow cells were re-seeded into the Quantum®, harvested and further characterised at P1. UC-MSCs were isolated enzymatically and cultured once on tissue culture plastic, before loading cells into the Quantum®, harvesting and characterising at P1. Quantum®-derived cultures were phenotyped in terms of immunoprofile, tri-lineage differentiation, response to inflammatory stimulus and telomere length, as were parallel cultures expanded on tissue culture plastic.

RESULTS

Bone marrow cell harvests from the Quantum® were 23.1 ± 16.2 × 10⁶ in 14 ± 2 days (P0) and 131 ± 84 × 10⁶ BM-MSCs in 13 ± 1 days (P1), whereas UC-MSC harvests from the Quantum® were 168 ± 52 × 10⁶ UC-MSCs after 7 ± 2 days (P1). Quantum®- and tissue culture plastic-expanded cultures at P1 adhered to criteria for MSCs in terms of cell surface markers, multipotency and plastic adherence, whereas the integrins, CD29, CD49c and CD51/61, were found to be elevated on Quantum®-expanded BM-MSCs. Rapid culture expansion in the Quantum® did not cause shortened telomeres when compared to cultures on tissue culture plastic. Immunomodulatory gene expression was variable between donors but showed that all MSCs upregulated indoleamine 2, 3-dioxygenase (IDO).

CONCLUSIONS

The results presented here demonstrate that the Quantum® can be used to expand large numbers of MSCs from bone marrow and umbilical cord tissues for next-generation large-scale manufacturing, without impacting on many of the properties that are characteristic of MSCs or potentially therapeutic. Using the Quantum®, we can obtain multiple MSC doses from a single manufacturing run to treat many patients. Together, our findings support the development of cheaper cell-based treatments.

Quantitative Multimodal Evaluation of Passaging Human Neural Crest Stem Cells for Peripheral Nerve Regeneration

Peripheral nerve injury is a major burden to societies worldwide, however, current therapy options (e.g. autologous nerve grafts) are unable to produce satisfactory outcomes. Many studies have shown that stem cell transplantation holds great potential for peripheral nerve repair, and human neural crest stem cells (hNCSCs), which give rise to a variety of tissues in the peripheral nervous system, are particularly promising. NCSCs are one of the best candidates for clinical translation, however, to ensure the viability and quality of NCSCs for research and clinical use, the effect of in vitro cell passaging on therapeutic effects needs be evaluated given that passaging is required to expand NCSCs to meet the demands of transplantation in preclinical research and clinical trials. To date, no study has investigated the quality of NCSCs past the 5th passage in vivo. In this study, we employed a multimodal evaluation system to investigate changes in outcomes between transplantation with 5th (p5) and 6th passage (p6) NCSCs in a 15 mm rat sciatic nerve injury and repair model. Using CatWalk gait analysis, gastrocnemius muscle index, electrophysiology, immunohistochemistry, and histomorphometric analysis, we showed that p6 NCSCs demonstrated decreased cell survival, Schwann-cell differentiation, axonal growth, and functional outcomes compared to p5 NCSCs (all p < 0.05). In conclusion, p6 NCSCs showed significantly reduced therapeutic efficacy compared to p5 NCSCs for peripheral nerve regeneration.

Connexin 43-Mediated Mitochondrial Transfer of iPSC-MSCs Alleviates Asthma Inflammation

We previously identified an immunomodulatory role of human induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (MSCs) in asthmatic inflammation. Mitochondrial transfer from bone marrow MSCs to epithelial cells can result in the attenuation of acute lung injury in mice. However, the effects of mitochondrial transfer from iPSC-MSCs to epithelial cells in asthma and the mechanisms underlying these effects are unclear. We found that iPSC-MSC transplantation significantly reduced T helper 2 cytokines, attenuated the mitochondrial dysfunction of epithelial cells, and alleviated asthma inflammation in mice. Tunneling nanotubes (TNTs) were formed between iPSC-MSCs and epithelial cells, and mitochondrial transfer from iPSC-MSCs to epithelial cells via TNTs was observed both in vitro and in mice. Overexpression or silencing of connexin 43 (CX43) in iPSC-MSCs demonstrated that CX43 plays a critical role in the regulation of TNT formation by mediating mitochondrial transfer between iPSC-MSCs and epithelial cells. This study provides a therapeutic strategy for targeting asthma inflammation.

Proteomic Profiling of Native Unpassaged and Culture-Expanded Mesenchymal Stromal Cells (MSC)

Human culture-expanded mesenchymal stromal cells (MSC) are being considered for multiple therapeutic applications because of their regenerative and anti-inflammatory properties. Although a large number of MSC can be propagated from a small initial sample, several lines of evidence indicate that MSC lose their immunosuppressive and regenerative potency aftaer multiple passages. In this report, we use the FACSCAP Lyoplate proteomic analysis system to detect changes in cell surface protein expression of CD45^- /CD31^- /CD34^- /CD73⁺ /CD105⁺ stromal cells in unpassaged bone marrow (BM) and through 10 serial culture passages. We provide for the first time a detailed characterization of native unpassaged BM MSC (0.08% of BM mononuclear cells) as well as the changes that occur during the initial expansion. Adipogenic and osteogenic differentiative potential was determined though the serial passages and correlated with immunophenotypic changes and senescence. Among the most prominent were striking decreases in Fas ligand, CD98, CD205, and CD106, accompanied by a gain in the expression of CD49c, CD63, CD98, and class 1 and class 2 major histocompatibility complex (MHC) molecules. Other molecules that are down-modulated with later passage include CD24, CD54, CD59, CD243/P-glycoprotein, and CD273/PD-L2. Early senescence, as defined by the loss of replicative capacity occurring with the loss of differentiative capacity, increase in CDKN2A p16, and increased time to confluence, was accompanied by loss of the motility-associated metalloproteinase CD10 and the proliferation-associated transferrin receptor CD71. Among the strongest statistical associations were loss of MAC-inhibitory protein/CD59, loss of ICAM-1/CD54, and increase in CDKN2A as a function of increasing passage, as well as increased CD10 expression with adipogenic and osteogenic capacities. The data provide a clear set of markers that can be used to assess MSC quality. We suggest that clinically relevant numbers of highly functional low passage MSC can be manufactured starting with large quantities of BM, which are readily available from cadaveric organ donors.

Human Herpes simplex 1 virus infection of endometrial decidual tissue-derived MSC alters HLA-G expression and immunosuppressive functions

OBJECTIVES

Mesenchymal stromal/stem cells have immunosuppressive functions. Our previous results demonstrated that one of the players of this immunomodulation can be ascribed to the Human Leukocyte Antigen-G. HLA-G, a non classical HLA class I antigen, is involved in immune tolerance during pregnancy, organ transplantation, autoimmune and inflammatory diseases. In this study we wanted to verify whether human endometrial decidual tissue derived (EDT)-MSC could express HLA-G. Additionally we assessed the permissivity to Human Herpesvirus infections, using HSV-1 as a model, and the possible effect on EDT-MSC immunosuppressive functions towards peripheral blood mononuclear cell (PBMC) proliferation.

METHODS

We analyzed immune-inhibitory functions and HLA-G expression in human EDT-MSC before and after HSV-1 infection.

RESULTS

We observed that EDT-MSC express HLA-G molecules, that partly are responsible for the immune-inhibitory functions of EDT-MSC towards PBMC proliferation. EDT-MSC are permissive for a productive infection by HSV-1, that decreases HLA-G expression and affects EDT-MSC immune-inhibitory functions.

CONCLUSIONS

We demonstrate that EDT-MSC are susceptible to HSV-1 infection, that reduces HLA-G expression and their immune-inhibitory function. These data could have a clinical implication in the use of EDT-MSC as an immunosuppressant, in particular in steroid-refractory GvHD after allogeneic hematopoietic stem cell transplantation and in autoimmune diseases.

Induced pluripotent stem cell-derived mesenchymal stem cells activate quiescent T cells and elevate regulatory T cell response via NF-κB in allergic rhinitis patients

Background

It has been demonstrated previously that induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (MSCs) have immunosuppressive effects on activated T cells. However, the effects of iPSC-MSCs on quiescent T cells are still unknown. The aim of this study was to identify the immunomodulatory role of iPSC-MSCs on resting peripheral blood mononuclear cells (PBMCs) from allergic rhinitis (AR) patients.

Methods

PBMCs were cocultured with iPSC-MSCs without any stimulation, following which lymphocyte proliferation, activation of T cells, T_H1/T_H2 and regulatory T (Treg) cell differentiation, and Treg cell function were analyzed. The roles of soluble factors and cell–cell contact were examined to investigate the mechanisms involved.

Results

iPSC-MSCs promoted the proliferation of resting lymphocytes, activated CD4⁺ and CD8⁺ T cells, and upregulated and activated Treg cells without any additional stimulation. In addition, iPSC-MSCs balanced biased T_H1/T_H2 cytokine levels. Cell–cell contact was confirmed to be a possible mechanism involved. NF-κB was identified to play an important role in the immunomodulatory effects of iPSC-MSCs on quiescent T cells.

Conclusions

iPSC-MSCs activate quiescent T cells and elevate regulatory T-cell response in AR patients, suggesting different immunomodulatory functions of iPSC-MSCs according to the phases of diseases. Therefore, iPSC-MSCs are a potential therapeutic candidate for treating allergic airway inflammation.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0896-z) contains supplementary material, which is available to authorized users.

Cryopreserved or Fresh Mesenchymal Stromal Cells: Only a Matter of Taste or Key to Unleash the Full Clinical Potential of MSC Therapy?

Mesenchymal stromal cells (MSCs) harbor great therapeutic potential for numerous diseases. From early clinical trials, success and failure analysis, bench-to-bedside and back-to-bench approaches, there has been a great gain in knowledge, still leaving a number of questions to be answered regarding optimal manufacturing and quality of MSCs for clinical application. For treatment of many acute indications, cryobanking may remain a prerequisite, but great uncertainty exists considering the therapeutic value of freshly thawed (thawed) and continuously cultured (fresh) MSCs. The field has seen an explosion of new literature lately, outlining the relevance of the topic. MSCs appear to have compromised immunomodulatory activity directly after thawing for clinical application. This may provide a possible explanation for failure of early clinical trials. It is not clear if and how quickly MSCs recover their full therapeutic activity, and if the "cryo stun effect" is relevant for clinical success. Here, we will share our latest insights into the relevance of these observations for clinical practice that will be discussed in the context of the published literature. We argue that the differences of fresh and thawed MSCs are limited but significant. A key issue in evaluating potency differences is the time point of analysis after thawing. To date, prospective double-blinded randomized clinical studies to evaluate potency of both products are lacking, although recent progress was made with preclinical assessment. We suggest refocusing therapeutic MSC development on potency and safety assays with close resemblance of the clinical reality.

The metabolic syndrome alters the miRNA signature of porcine adipose tissue-derived mesenchymal stem cells

Autologous transplantation of mesenchymal stem cells (MSCs) is a viable option for the treatment of several diseases. Evidence indicates that MSCs release extracellular vesicles (EVs) and that EVs shuttle miRNAs to damaged parenchymal cells to activate an endogenous repair program. We hypothesize that comorbidities may interfere with the packaging of cargo in MSC-derived EVs. Therefore, we examined whether metabolic syndrome (MetS) modulates the miRNA content packed within MSC-derived EVs. MSCs were collected from swine abdominal adipose tissue after 16 weeks of lean or obese diet (n = 7 each). Next-generation RNA sequencing of miRNAs (miRNA-seq) was performed to identify miRNAs enriched in MSC-derived EVs and their predicted target genes. Functional pathway analysis of the top 50 target genes of the top 4 miRNAs enriched in each group was performed using gene ontology analysis. Lean- and MetS-EVs were enriched in, respectively, 14 and 8 distinct miRNAs. Target genes of miRNAs enriched in MetS-EVs were implicated in the development of MetS and its complications, including diabetes-related pathways, validated transcriptional targets of AP1 family members Fra1 and Fra2, Class A/1 (Rhodopsin-like receptors), and Peptide ligand-binding receptors. In contrast, miRNAs enriched in Lean EVs target primarily EphrinA-EPHA and the Rho family of GTPases. MetS alters the miRNA content of EVs derived from porcine adipose tissue MSCs. These alterations could impair the efficacy and limit the therapeutic use of autologous MSCs in subjects with MetS. Our findings may assist in developing adequate regenerative strategies to preserve the reparative potency of MSCs in individuals with MetS. © 2017 International Society for Advancement of Cytometry.

Progesterone prevents epithelial-mesenchymal transition of ovine amniotic epithelial cells and enhances their immunomodulatory properties

The in vitro expansion is detrimental to therapeutic applications of amniotic epithelial cells (AEC), an emerging source of fetal stem cells. This study provides molecular evidences of progesterone (P4) role in preventing epithelial-mesenchymal transition (EMT) in ovine AEC (oAEC). oAEC amplified under standard conditions spontaneously acquired mesenchymal properties through the up-regulation of EMT-transcription factors. P4 supplementation prevented phenotype shift by inhibiting the EMT-inducing mechanism such as the autocrine production of TGF-β and the activation of intracellular-related signaling. The effect of P4 still persisted for one passage after steroid removal from culture as well as steroid supplementation promptly reversed mesenchymal phenotype in oAEC which have experienced EMT during amplification. Furthermore, P4 promoted an acute up-regulation of pluripotent genes whereas enhanced basal and LPS-induced oAEC anti-inflammatory response with an increase in anti-inflammatory and a decrease in pro-inflammatory cytokines expression. Altogether, these results indicate that P4 supplementation is crucial to preserve epithelial phenotype and to enhance biological properties in expanded oAEC. Therefore, an innovative cultural approach is proposed in order to improve therapeutic potential of this promising source of epithelial stem cells.

Effects of mesenchymal stem cells from human induced pluripotent stem cells on differentiation, maturation, and function of dendritic cells

BACKGROUND

Mesenchymal stem cells (MSCs) have potent immunomodulatory effects on multiple immune cells and have great potential in treating immune disorders. Induced pluripotent stem cells (iPSCs) serve as an unlimited and noninvasive source of MSCs, and iPSC-MSCs have been reported to have more advantages and exhibit immunomodulation on T lymphocytes and natural killer cells. However, the effects of iPSC-MSCs on dendritic cells (DCs) are unclear. The aim of this study is to investigate the effects of iPSC-MSCs on the differentiation, maturation, and function of DCs.

METHODS

Human monocyte-derived DCs were induced and cultured in the presence or absence of iPSC-MSCs. Flow cytometry was used to analyze the phenotype and functions of DCs, and enzyme-linked immunosorbent assay (ELISA) was used to study cytokine production.

RESULTS

In this study, we successfully induced MSCs from different clones of human iPSCs. iPSC-MSCs exhibited a higher proliferation rate with less cell senescence than BM-MSCs. iPSC-MSCs inhibited the differentiation of human monocyte-derived DCs by both producing interleukin (IL)-10 and direct cell contact. Furthermore, iPSC-MSCs did not affect immature DCs to become mature DCs, but modulated their functional properties by increasing their phagocytic ability and inhibiting their ability to stimulate proliferation of lymphocytes. More importantly, iPSC-MSCs induced the generation of IL-10-producing regulatory DCs in the process of maturation, which was mostly mediated by a cell-cell contact mechanism.

CONCLUSIONS

Our results indicate an important role for iPSC-MSCs in the modulation of DC differentiation and function, supporting the clinical application of iPSC-MSCs in DC-mediated immune diseases.

Intra-articular Implantation of Mesenchymal Stem Cells, Part 1: A Review of the Literature for Prevention of Postmeniscectomy Osteoarthritis

Osteoarthritis (OA) after a partial or total meniscectomy procedure is a common pathology. Because of the high incidence of meniscectomy in the general population, as well as the significant burden of knee OA, there is increasing interest in determining methods for delaying postmeniscectomy OA. Biological therapies, including mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), have been proposed as possible therapies that could delay OA in this and other settings. Several studies in various animal models have evaluated the effect of injecting MSCs into the knee joints of animals with OA induced either by meniscal excision with or without anterior cruciate ligament transection. When compared with control groups receiving injections without progenitor cells, short-term benefits in the experimental groups have been reported. In human subjects, there are limited data to determine the effect of biological therapies for use in delaying or preventing the onset of OA after a meniscectomy procedure. The purpose of this review is to highlight the findings in the presently available literature on the use of intra-articular implantation of MSCs postmeniscectomy and to offer suggestions for future research with the goal of delaying or treating early OA postmeniscectomy with MSCs.

External factors influencing mesenchymal stem cell fate in vitro

Mesenchymal stem cells (MSCs) have extensive potentials, which make them attractive candidates for the developmental biology, drug discovery and regenerative medicine. However, the use of MSCs is limited by their scarceness in tissues and in culture conditions. They also exhibit various degrees of potency which subsequently influencing their applications. Nowadays, questions remain about how self-renewal and differentiation of MSCs can be controlled in vitro and in vivo, how they will behave and migrate to the right place and how they modulate the immune system. Therefore, identification of factors and culture conditions to affect the fate and function of MSCs may be effective to enhance their applications in clinical situations. Studies have indicated that the fate of MSCs in culture is influenced by various external factors, including the specific cell source, donor age, plating density, passage number and plastic surface quality. Some other factors such as cell culture media and their supplementary factors, O₂ concentration, mechano-/electro-stimuli and three-dimensional scaffolds are also shown to be influential. This review addresses the current state of MSC research for describing and discussing the findings about external factors that influence the fate and function of MSCs. Additionally, the new discoveries and suggestions regarding their molecular mechanisms will be explained.

Mesenchymal stromal cells derived from whole human umbilical cord exhibit similar properties to those derived from Wharton's jelly and bone marrow

Mesenchymal stromal cells (MSC) can be isolated from several regions of human umbilical cords, including Wharton's jelly (WJ), artery, vein or cord lining. These MSC appear to be immune privileged and are promising candidates for cell therapy. However, isolating MSC from WJ, artery, vein or cord lining requires time-consuming tissue dissection. MSC can be obtained easily via briefly digesting complete segments of the umbilical cord, likely containing heterogenous or mixed populations of MSC (MC-MSC). MC-MSC are generally less well characterized than WJ-MSC, but nevertheless represent a potentially valuable population of MSC. This study aimed to further characterize MC-MSC in comparison to WJ-MSC and also the better-characterized bone marrow-derived MSC (BM-MSC). MC-MSC proliferated faster, with significantly faster doubling times reaching passage one 8.8 days sooner and surviving longer in culture than WJ-MSC. All MSC retained the safety aspect of reducing telomere length with increasing passage number. MSC were also assessed for their ability to suppress T-cell proliferation and for the production of key markers of pluripotency, embryonic stem cells, tolerogenicity (CD40, CD80, CD86 and HLA-DR) and immunomodulation (indoleamine 2,3-dioxygenase [IDO] and HLA-G). The MC-MSC population displayed all of the positive attributes of WJ-MSC and BM-MSC, but they were more efficient to obtain and underwent more population doublings than from WJ, suggesting that MC-MSC are promising candidates for allogeneic cell therapy in regenerative medicine.