Explant culture: An advantageous method for isolation of mesenchymal stem cells from human tissues

Rapid method for paraffin embedding of precision-cut liver slices

Precision-cut liver slices (PCLS) are tissue explants extensively used as an ex vivo model for metabolism and toxicity studies. When in vitro assays are conducted, it is imperative to perform a histomorphological evaluation as part of the viability analyses throughout the assay time. It is considered that good quality PCLS histological sections are difficult to obtain because they are hard to manipulate, and may shrink or fold during processing. Moreover, bibliography is not detailed on the embedding processes used. In this article, we propose an adjusted and rapid method for paraffin embedding of PCLS from crossbreed steers. Each PCLS was covered with a piece of gauze and placed into a histological cassette. These cassettes were submitted to a series of baths: 80 % ethanol for 10 min; 3 baths of 96 % ethanol for 10 min; 3 baths of butanol for 10 min; 1 bath of butanol-paraffin (1:1) for 20 min in a 60 °C laboratory oven; and 3 baths of paraffin for 20 min in a 60 °C laboratory oven. Folded paper boxes were used to produce paraffin blocks. It was possible to obtain complete sections with preserved cell morphology and no artifacts, and tissue appearance was similar to previous PCLS processed through the routine protocol, demonstrating the adequacy of the method implemented.

Optimizing Mesenchymal Stem Cells for Regenerative Medicine: Influence of Diabetes, Obesity, Autoimmune, and Inflammatory Conditions on Therapeutic Efficacy: A Review

Mesenchymal stem cells (MSCs) are a promising tool that may be used in regenerative medicine. Thanks to their ability to differentiate and paracrine signaling, they can be used in the treatment of many diseases. Undifferentiated MSCs can support the regeneration of surrounding tissues through secreted substances and exosomes. This is possible thanks to the production of growth factors. These factors stimulate the growth of neighboring cells, have an anti-apoptotic effect, and support angiogenesis, and MSCs also have an immunomodulatory effect. The level of secreted factors may vary depending on many factors. Apart from the donor's health condition, it is also influenced by the source of MSCs, methods of harvesting, and even the banking of cells. This work is a review of research on how the patient's health condition affects the properties of obtained MSCs. The review discusses the impact of the patient's diabetes, obesity, autoimmune diseases, and inflammation, as well as the impact of the source of MSCs and methods of harvesting and banking cells on the phenotype, differentiation capacity, anti-inflammatory, angiogenic effects, and proliferation potential of MSCs. Knowledge about specific clinical factors allows for better use of the potential of stem cells and more appropriate targeting of procedures for collecting, multiplying, and banking these cells, as well as for their subsequent use. This article aims to review the characteristics, harvesting, banking, and paracrine signaling of MSCs and their role in diabetes, obesity, autoimmune and inflammatory diseases, and potential role in regenerative medicine.

Adipose Tissue and Umbilical Cord Tissue: Potential Sources of Mesenchymal Stem Cells for Liver Fibrosis Treatment

Background/Aims

Mesenchymal stem cells (MSCs) are potential alternatives for liver fibrosis treatment; however, their optimal sources remain uncertain. This study compares the ex-vivo expansion characteristics of MSCs obtained from adipose tissue (AT) and umbilical cord (UC) and assesses their therapeutic potential for liver fibrosis treatment.

Methods

Since MSCs from early to mid-passage numbers (P2-P6) are preferable for cellular therapy, we investigated the growth kinetics of AT-MSCs and UC-MSCs up to P6 and evaluated their therapeutic effects in a rat model of liver fibrosis induced by diethylnitrosamine.

Results

Results from the expansion studies demonstrated that both cell types exhibited bona fide characteristics of MSCs, including surface antigens, pluripotent gene expression, and differentiation potential. However, AT-MSCs demonstrated a shorter doubling time (58.2 ± 7.3 vs. 82.3 ± 4.3 h; P < 0.01) and a higher population doubling level (10.1 ± 0.7 vs. 8.2 ± 0.3; P < 0.01) compared to UC-MSCs, resulting in more cellular yield (230 ± 9.0 vs. 175 ± 13.2 million) in less time. Animal studies demonstrated that both MSC types significantly reduced liver fibrosis (P < 0.05 vs. the control group) while also improving liver function and downregulating fibrosis-associated gene expression.

Conclusion

AT-MSCs and UC-MSCs effectively reduce liver fibrosis. However, adipose cultures display an advantage by yielding a higher number of MSCs in a shorter duration, rendering them a viable choice for scenarios requiring immediate single-dose administration, often encountered in clinical settings.

Molecular Prospective on Malignant Transformation of Mesenchymal Stem Cells: An Issue in Cell Therapy

Mesenchymal stem cell (MSCs) therapy, as a rapidly developing area of medicine, holds great promise for the treatment of a variety of medical conditions. MSCs are multipotent stem cells that can be isolated from various tissues and could self-renew and differentiate. They secrete cytokines and trophic factors that create a regenerative microenvironment and have immunomodulatory properties. Although clinical trials have been conducted with MSCs in various diseases, concerns regarding the possibility of malignant transformation of these cells have been raised. The studies showed a higher rate of hematological malignancy and carcinogenesis in experimental models after MSC transplantation. The mechanisms underlying malignant transformation of MSCs are complex and not fully understood, but they are believed to involve the presence of special signaling molecules and alterations in cell behavior regulation pathways. Possible pathways that lead to MSCs' oncogenic transformation occur through two mechanisms: spontaneous and stimulated malignant transformation, including cell fusion, fusion proteins, and the tumor microenvironment. MSC-based therapies have the potential to revolutionize medicine, and addressing the issue of malignancy is crucial to ensure their safety and efficacy. Therefore, the purpose of the present review is to summarize the potential mechanisms of the malignant transformation of MSCs. [Figure: see text].

Intra-arterial delivery of neurospheres into isolated perfused porcine colons: a proof of concept

Cell replacement in aganglionic intestines is a promising, yet merely experimental tool for the therapy of congenital dysganglionosis of the enteric nervous system like Hirschsprung disease. While the injection of single cells or neurospheres to a defined and very restricted location is trivial, the translation to the clinical application, where large aganglionic or hypoganglionic areas need to be colonized (hundreds of square centimetres), afford a homogeneous distribution of multiple neurospheres all over the affected tissue areas. Reaching the entire aganglionic area in vivo is critical for the restoration of peristaltic function. The latter mainly depends on an intact nervous system that extends throughout the organ. Intra-arterial injection is a common method in cell therapy and may be the key to delivering cells or neurospheres into the capillary bed of the colon with area-wide distribution. We describe an experimental method for monitoring the distribution of a defined number of neurospheres into porcine recta ex vivo, immediately after intra-arterial injection. We designed this method to localize grafting sites of single neurospheres in precise biopsies which can further be examined in explant cultures. The isolated perfused porcine rectum allowed us to continuously monitor the perfusion pressure. A blockage of too many capillaries would lead to an ischaemic situation and an increase of perfusion pressure. Since we could demonstrate that the area-wide delivery of neurospheres did not alter the overall vascular resistance, we showed that the delivery does not significantly impair the local circulation.

A Simple High Yield Technique for Isolation of Wharton's Jelly-derived Mesenchymal Stem Cell

Background

The isolation of Mesenchymal Stem Cells (MSCs) from various tissues is possible, with the umbilical cord emerging as a competitive alternative to bone marrow. In order to fulfill the demands of cell therapy, it is essential to generate stem cells on a clinical scale while minimizing time, cost, and contamination. Here is a simple and effective protocol for isolating MSC from Wharton's Jelly (WJ-MSC) using the explant method with various supplements.

Methods

Utilizing the explant method, small fragments of Wharton's jelly from the human umbilical cord were cultured in a flask. The multipotency of the isolated cells, were confirmed by their differentiation ability to osteocyte and adipocyte. Additionally, the immunophenotyping of WJ-MSCs showed positive expression of CD73, CD90, and CD105, while remaining negative for hematopoietic markers CD34 and CD45, meeting the criteria for WJ-MSC identification. Following that, to evaluate cells' proliferative capacity, various supplements, including basic Fibroblast Growth Factor (bFGF), Non-Essential amino acids (NEA), and L-Glutamine (L-Gln) were added to either alpha-Minimal Essential Medium (α-MEM) or Dulbecco's Modified Eagle's Medium-F12 (DMEM-F12), as the basic culture media.

Results

WJ-MSCs isolated by the explant method were removed from the tissue after seven days and transferred to the culture medium. These cells differentiated into adipocyte and osteocyte lineages, expressing CD73, CD90, and CD105 positively and CD34 and CD45 negatively. The results revealed that addition of bFGF to α-MEM or DMEMF12 media significantly increased the proliferation of MSCs when compared to the control group. However, there were no significant differences observed when NEA or LGln were added.

Conclusion

Although bFGF considerably enhances cell proliferation, our study demonstrates that MSCs can grow and expand when properly prepared Wharton's jelly tissues of the human umbilical cord.

Rebuilding the microenvironment of primary tumors in humans: a focus on stroma

Conventional tumor models have critical shortcomings in that they lack the complexity of the human stroma. The heterogeneous stroma is a central compartment of the tumor microenvironment (TME) that must be addressed in cancer research and precision medicine. To fully model the human tumor stroma, the deconstruction and reconstruction of tumor tissues have been suggested as new approaches for in vitro tumor modeling. In this review, we summarize the heterogeneity of tumor-associated stromal cells and general deconstruction approaches used to isolate patient-specific stromal cells from tumor tissue; we also address the effect of the deconstruction procedure on the characteristics of primary cells. Finally, perspectives on the future of reconstructed tumor models are discussed, with an emphasis on the essential prerequisites for developing authentic humanized tumor models.

Impact of multiple isolation procedures on the differentiation potential of adipose derived canine mesenchymal stem cells

OBJECTIVE

In regenerative biology, the most commonly used cells are adipose tissue-derived mesenchymal stem cells (AD-MSCs). This is due to the abundance and easy accessibility of AD-MSCs.

METHODS

In this study, canine AD-MSCs were harvested from different anatomical locations, i.e., subcutaneous (SC), omental (OM), and perirenal (PR). Various isolation techniques namely explants (TRT-I), collagenase-digestion (TRT-II), collagenase-digested explants (TRT-III), and trypsin-digested explants (TRT-IV) were used to segregate the MSCs to evaluate cell doubling time, viability, and adipogenic/osteogenic lineage differentiation potential.

RESULTS

The study showed that the SC stem cells had superior growth kinetics compared to other tissues, while the cells isolated through TRT-II performed better than the other cell isolation procedures. The metabolic status of cells isolated from dog adipose tissue indicated that all cells had adequate metabolic rates. However, SC-MSCs derived from TRT-III and TRT-IV outperformed those derived from TRT-I and TRT-II. The differentiation analysis revealed that cells differentiate into adipogenic and osteogenic lineage regardless of treatment, as demonstrated by positive oil red O (ORO) and Alizarin Red S (ALZ) stain. It is worth mentioning that cells derived from TRT-III had larger and more intracellular droplets compared to the other treatments. The TRT-I, -II, and -III showed greater osteogenic differentiation in cells isolated from PR and OM regions compared to SC-derived cells. However, the TRT-IV resulted in better osteogenic differentiation in cells from SC, followed by the OM and PR-derived cells.

CONCLUSION

It is concluded that all methods of MSCs isolation from adipose tissues are successful; however, the TRT-II had the highest rate of cell re-assortment from the SC, while, TRT-II and -IV are most suitable for isolating cells from PR and OM adipose tissue.

The Genetic Aspects of Periodontitis Pathogenesis and the Regenerative Properties of Stem Cells

Periodontitis (PD) is a prevalent and chronic inflammatory disease with a complex pathogenesis, and it is associated with the presence of specific pathogens, such as Porphyromonas gingivalis. Dysbiosis and dysregulated immune responses ultimately lead to chronic inflammation as well as tooth and alveolar bone loss. Multiple studies have demonstrated that genetic polymorphisms may increase the susceptibility to PD. Furthermore, gene expression is modulated by various epigenetic mechanisms, such as DNA methylation, histone modifications, or the activity of non-coding RNA. These processes can also be induced by PD-associated pathogens. In this review, we try to summarize the genetic processes that are implicated in the pathogenesis of PD. Furthermore, we discuss the use of these mechanisms in diagnosis and therapeutic purposes. Importantly, novel treatment methods that could promote tissue regeneration are greatly needed in PD. In this paper, we also demonstrate current evidence on the potential use of stem cells and extracellular vesicles to stimulate tissue regeneration and suppress inflammation. The understanding of the molecular mechanisms involved in the pathogenesis of PD, as well as the impact of PD-associated bacteria and stem cells in these processes, may enhance future research and ultimately improve long-term treatment outcomes.

Research Progress on Cardiac Tissue Construction of Mesenchymal Stem Cells for Myocardial Infarction

Heart failure is still the main complication affecting the prognosis of acute myocardial infarction (AMI), and mesenchymal stem cells (MSCs) are an effective treatment to replace necrotic myocardium and improve cardiac functioning. However, the transplant survival rate of MSCs still presents challenges. In this review, the biological characteristics of MSCs, the progress of mechanism research in the treatment of myocardial infarction, and the advances in improving the transplant survival rate of MSCs in the replacement of necrotic myocardial infarction are systematically described. From a basic to advanced clinical research, MSC transplants have evolved from a pure injection, an exosome injection, the genetic modification of MSCs prior to injection to the cardiac tissue engineering of MSC patch grafting. This study shows that MSCs have wide clinical applications in the treatment of AMI, suggesting improved myocardial tissue creation. A broader clinical application prospect will be explored and developed to improve the survival rate of MSC transplants and myocardial vascularization.

An Enzyme-Free Method for Isolation and Expansion of Muscle Stem Cells for Cultivated Meat Applications

Cultivated meat, an alternative to conventional meat, holds great promise in alleviating environmental and ethical concerns. Skeletal muscle stem cell isolation is a critical phase in cultivated meat production, and efficiency is a major determinant in the final differentiated muscle cell yield. The conventional enzymatic dissociation method for cell isolation presents drawbacks, including added costs and the destruction of vital extracellular matrix components. We developed an alternative cell isolation technique, explant cell isolation, to isolate muscle stem cells from muscle tissue. The present protocol yields myogenic cell populations, mainly composed of skeletal muscle stem cells without the use of enzymes, and through a simplified process. Overall, the explant method allows for propagation of cells in their natural environment, preserving intricate cell-cell and cell-matrix interactions, resulting in both economic efficiency and consistent generation of high-quality cells.

Understanding conceptus-maternal interactions: what tools do we need to develop?

Communication between the maternal endometrium and developing embryo/conceptus is critical to support successful pregnancy to term. Studying the peri-implantation period of pregnancy is critical as this is when most pregnancy loss occurs in cattle. Our current understanding of these interactions is limited, due to the lack of appropriate in vitro models to assess these interactions. The endometrium is a complex and heterogeneous tissue that is regulated in a transcriptional and translational manner throughout the oestrous cycle. While there are in vitro models to study endometrial function, they are static and 2D in nature or explant models and are limited in how well they recapitulate the in vivo endometrium. Recent developments in organoid systems, microfluidic approaches, extracellular matrix biology, and in silico approaches provide a new opportunity to develop in vitro systems that better model the in vivo scenario. This will allow us to investigate in a more high-throughput manner the fundamental molecular interactions that are required for successful pregnancy in cattle.

Adenosine metabolism by mesenchymal stromal cells isolated from different human tissues

Mesenchymal stromal cells (MSCs) have unique biological properties and play important functions, which make them attractive tools for cell-based therapies. The basic mechanisms of these cells are not fully understood. However, the adenosinergic pathway contributes to the main effects attributed to MSCs. Adenosine is a highly immunosuppressive molecule and exerts a central role in inflammation by neutralizing the proinflammatory ATP influence. This nucleoside is produced by purinergic signaling, an important physiological pathway for MSCs, which involves proliferation, migration, differentiation, and apoptosis. Therefore, in this study, we analyzed the extracellular AMP hydrolysis and consequent adenosine production, as well as the expression of CD73 and adenosine receptors on the cell surface of MSCs isolated from different human tissues: dermis (D-MSCs), adipose tissue (AD-MSCs), and umbilical cord (UC-MSCs). All cells confirmed their multipotent capacity by adipogenic, osteogenic, and chondrogenic differentiation, as well as the expression of cell surface markers including CD44 + , CD105 + , and CD90 + . All MSCs expressed similar levels of CD73 and CD26 without a statistical difference among the different tissues, whereas ADA expression was lower in AD-MSCs. In addition, A1R and A3R mRNA levels were higher in D-MSCs and AD-MSCs, respectively. Enzymatic assay showed that AD-MSCs have the highest hydrolysis rate of AMP, leading to increased amount of adenosine production. Moreover, despite all MSCs completely hydrolyze extracellular AMP generating adenosine, the pattern of nucleosides metabolism was different. Therefore, although MSCs share certain characteristics as the multilineage potential and immunophenotype, they show different adenosinergic profiles according to tissue origin.

Treatment of Naturally Occurring Tendon Disease with Allogeneic Multipotent Mesenchymal Stromal Cells: A Randomized, Controlled, Triple-Blinded Pilot Study in Horses

The treatment of tendinopathies with multipotent mesenchymal stromal cells (MSCs) is a promising option in equine and human medicine. However, conclusive clinical evidence is lacking. The purpose of this study was to gain insight into clinical treatment efficacy and to identify suitable outcome measures for larger clinical studies. Fifteen horses with early naturally occurring tendon disease were assigned to intralesional treatment with allogeneic adipose-derived MSCs suspended in serum or with serum alone through block randomization (dosage adapted to lesion size). Clinicians and horse owners remained blinded to the treatment during 12 months (seven horses per group) and 18 months (seven MSC-group and five control-group horses) of follow-up including clinical examinations and diagnostic imaging. Clinical inflammation, lameness, and ultrasonography scores improved more over time in the MSC group. The lameness score difference significantly improved in the MSC group compared with the control group after 6 months. In the MSC group, five out of the seven horses were free of re-injuries and back to training until 12 and 18 months. In the control group, three out of the seven horses were free of re-injuries until 12 months. These results suggest that MSCs are effective for the treatment of early-phase tendon disease and provide a basis for a larger controlled study.

A newly improved method of primary cell culture: Tissue block with continuous adhesion subculture in skin fibroblast

BACKGROUND

Fibroblasts (FBs) have been widely used as a typical in vitro cell model for investigating the biological processes and cell pathophysiological mechanisms. However, FBs are prone to senescence in cell culture process after several passages. Thus, a new approach to cell culture is quite required to enhance the viability of cells.

OBJECTIVE

To explore a novel method of cell culture based on skin FBs.

METHODS

Dermal tissue blocks were obtained from BALB/c neonatal mice and randomly divided into experimental group and control group. The experimental group received the newly improved culture method, namely, continuous adherence subculture of tissue block (CASTB) method; while the traditional subculture method was applied in the control group. Cells at 1st, 5th and 10th passages were collected and identified by using histological/immunohistochemical and western blot analysis. Cellular viability, proliferation, senescence and apoptosis were analyzed through application of cell growth curve, CCK-8 assay, Ki67 assay, PCNA protein analysis, β-galactosidase staining, flow cytometry and western blot analysis.

RESULTS

Cells under two culture patterns exhibited spindle/irregular shape and vimentin positive expression. With the increase of passage times, the cellular growth rate in the control group gradually decreased, but no alterations emerged from the experimental group. CASTB method remarkably promoted cell growth and proliferation. Moreover, a greatly lower apoptosis and senescence tendency appeared in the experimental group than the control group with passages increasing.

CONCLUSION

The method of CASTB is superior to traditional subculture, offering a large number of primary FBs with higher efficiency and success rate and being worth of further popularization and application.

Manipulation of osteogenic and adipogenic differentiation of human degenerative disc and ligamentum flavum derived progenitor cells using IL-1β, IL-19, and IL-20

PURPOSE

To elucidate whether pro-inflammatory cytokines might influence the commitment of intervertebral disc (IVD)- and ligamentum flavum (LF)-derived progenitor cells toward either osteogenesis or adipogenesis, specifically Interleukin-1β (IL-1β), IL-19, and IL-20.

METHODS

Sixty patients with degenerative spondylolisthesis and lumbar or lumbosacral spinal stenosis were included in the study. Injuries to the spine, infections, and benign or malignant tumors were excluded. From nine patient samples, IVD- and LF-derived cells were isolated after primary culture, and two clinical samples were excluded due to mycoplasma infection. The effects of IL-1β, IL-19, as well as IL-20 in regulating osteogenic and adipogenic differentiation in vitro were investigated.

RESULTS

Primary IVD- and LF-derived cells were found to have a similar cell morphology and profile of surface markers (CD44, CD90, and CD105) as placenta-derived mesenchymal stem cells (MSCs). Primary IVD/LF cells have a high capacity to differentiate into osteocytes and adipocytes. IL-19 had a tendency to promote adipogenesis. IL-20 inhibited osteogenesis and promoted adipogenesis; IL-1β promoted osteogenesis but inhibited adipogenesis.

CONCLUSION

IL-1β, IL-19, and IL-20 impact the adipogenic and osteogenic differentiation of IVD-derived and LF-derived cells. Modulating the expression of IL-1β, IL-19, and IL-20 provides a potential avenue for controlling cell differentiation of IVD- and LF-derived cells, which might have beneficial effect for degenerative spondylolisthesis and spinal stenosis.

Multiple Dimensions of using Mesenchymal Stem Cells for Treating Liver Diseases: From Bench to Beside

Liver diseases impose a huge burden worldwide. Although hepatocyte transplantation has long been considered as a potential strategy for treating liver diseases, its clinical implementation has created some obvious limitations. As an alternative strategy, cell therapy, particularly mesenchymal stem cell (MSC) transplantation, is widely used in treating different liver diseases, including acute liver disease, acute-on-chronic liver failure, hepatitis B/C virus, autoimmune hepatitis, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Here, we summarize the status of MSC transplantation in treating liver diseases, focusing on the therapeutic mechanisms, including differentiation into hepatocyte-like cells, immunomodulating function with a variety of immune cells, paracrine effects via the secretion of various cytokines and extracellular vesicles, and facilitation of homing and engraftment. Some improved perspectives and current challenges are also addressed. In summary, MSCs have great potential in the treatment of liver diseases based on their multi-faceted characteristics, and more accurate mechanisms and novel therapeutic strategies stemming from MSCs will facilitate clinical practice.

Enzyme-free isolation of mesenchymal stem cells from decidua basalis of the human placenta

Mesenchymal stem cells (MSCs), also referred to as "medicinal signaling cells," have gained prominence as candidates for cell-based therapy and in clinical trials owing to their regenerative and therapeutic properties. Here, we present a protocol for isolating MSCs from the decidua basalis layer of human placenta using an explant culture approach. We describe steps for collecting, disinfecting, and plating placental tissue. We then detail procedures for characterizing the isolated MSCs through flow cytometry and in vitro differentiation.

Establishment of SV40 Large T-Antigen-Immortalized Yak Rumen Fibroblast Cell Line and the Fibroblast Responses to Lipopolysaccharide

The yak lives in harsh alpine environments and the rumen plays a crucial role in the digestive system. Rumen-associated cells have unique adaptations and functions. The yak rumen fibroblast cell line (SV40T-YFB) was immortalized by introducing simian virus 40 large T antigen (SV40T) by lentivirus-mediated transfection. Further, we have reported the effects of lipopolysaccharide (LPS) of different concentrations on cell proliferation, extracellular matrix (ECM), and proinflammatory mediators in SV40T-YFB. The results showed that the immortalized yak rumen fibroblast cell lines were identified as fibroblasts that presented oval nuclei, a fusiform shape, and positive vimentin and SV40T staining after stable passage. Chromosome karyotype analysis showed diploid characteristics of yak (n = 60). LPS at different concentrations inhibited cell viability in a dose-dependent manner. SV40T-YFB treated with LPS increased mRNA expression levels of matrix metalloproteinases (MMP-2 and MMP-9), inflammatory cytokines (TNF-α, IL-1β, IL-6), and urokinase-type plasminogen activator system components (uPA, uPAR). LPS inhibits the expression of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), plasminogen activator inhibitor-2 (PAI-2), fibronectin (FN), anti-inflammatory factor IL-10, and collagen I (COL I) in SV40T-YFB. Overall, these results suggest that LPS inhibits cell proliferation and induces ECM degradation and inflammatory response in SV40T-YFB.

Are genetic drift and stem cell adherence in laboratory culture issues for cultivated meat production?

Mesenchymal stem cell-based cultivated meat is a promising solution to the ecological and ethical problems posed by traditional meat production, since it exhibits a protein content and composition that is more comparable to original meat proteins than any other source of cultivated meat products, including plants, bacteria, and fungi. Nonetheless, the nature and laboratory behavior of mesenchymal stem cells pose two significant challenges for large-scale production: genetic drift and adherent growth in culture. Culture conditions used in the laboratory expose the cells to a selective pressure that causes genetic drift, which may give rise to oncogene activation and the loss of "stemness." This is why genetic and functional analysis of the cells during culture is required to determine the maximum number of passages within the laboratory where no significant mutations or loss of function are detected. Moreover, the adherent growth of mesenchymal stem cells can be an obstacle for their large-scale production since volume to surface ratio is limited for high volume containers. Multi-tray systems, roller bottles, and microcarriers have been proposed as potential solutions to scale-up the production of adherent cells required for cultivated meat. The most promising solutions for the safety problems and large-scale obstacles for cultivated meat production are the determination of a limit number of passages based on a genetic analysis and the use of microcarriers from edible materials to maximize the volume to surface proportion and decrease the downstream operations needed for cultivated meat production.

A novel 3D biofabrication strategy to improve cell proliferation and differentiation of human Wharton's jelly mesenchymal stromal cells for cell therapy and tissue engineering

Purpose: Obtaining sufficient numbers of cells in a short time is a major goal of cell culturing in cell therapy and tissue engineering. However, current bidimensional (2D) culture methods are associated to several limitations, including low efficiency and the loss of key cell differentiation markers on cultured cells. Methods: In the present work, we have designed a novel biofabrication method based on a three-dimensional (3D) culture system (FIBRIAGAR-3D). Human Wharton's jelly mesenchymal stromal cells (HWJSC) were cultured in 3D using 100%, 75%, 50%, and 25% concentrations of fibrin-agarose biomaterials (FA100, FA75, FA50 and FA25 group) and compared with control cells cultured using classical 2D systems (CTR-2D). Results: Our results showed a significant increase in the number of cells generated after 7 days of culture, with cells displaying numerous expansions towards the biomaterial, and a significant overexpression of the cell proliferation marker KI67 was found for the FA75 and FA100 groups. TUNEL and qRT-PCR analyses demonstrated that the use of FIBRIAGAR-3D was not associated with an induction of apoptosis by cultured cells. Instead, the 3D system retained the expression of typical phenotypic markers of HWJSC, including CD73, CD90, CD105, NANOG and OCT4, and biosynthesis markers such as types-I and IV collagens, with significant increase of some of these markers, especially in the FA100 group. Finally, our analysis of 8 cell signaling molecules revealed a significant decrease of GM-CSF, IFN-g, IL2, IL4, IL6, IL8, and TNFα, suggesting that the 3D culture system did not induce the expression of pro-inflammatory molecules. Conclusion: These results confirm the usefulness of FIBRIAGAR-3D culture systems to increase cell proliferation without altering cell phenotype of immunogenicity and opens the door to the possibility of using this novel biofabrication method in cell therapy and tissue engineering of the human cornea, oral mucosa, skin, urethra, among other structures.

New strategies of neurodegenerative disease treatment with extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs)

Neurodegenerative diseases are characterized by the progressive loss of neurons and intricate interactions between different cell types within the affected regions. Reliable biomarkers that can accurately reflect disease activity, diagnose, and monitor the progression of neurodegenerative diseases are crucial for the development of effective therapies. However, identifying suitable biomarkers has been challenging due to the heterogeneous nature of these diseases, affecting specific subsets of neurons in different brain regions. One promising approach for promoting brain regeneration and recovery involves the transplantation of mesenchymal stem cells (MSCs). MSCs have demonstrated the ability to modulate the immune system, promote neurite outgrowth, stimulate angiogenesis, and repair damaged tissues, partially through the release of their extracellular vesicles (EVs). MSC-derived EVs retain some of the therapeutic characteristics of their parent MSCs, including their ability to regulate neurite outgrowth, promote angiogenesis, and facilitate tissue repair. This review aims to explore the potential of MSC-derived EVs as an emerging therapeutic strategy for neurodegenerative diseases, highlighting their role in modulating disease progression and promoting neuronal recovery. By elucidating the mechanisms by which MSC-derived EVs exert their therapeutic effects, we can advance our understanding and leverage their potential for the development of novel treatment approaches in the field of neurodegenerative diseases.

TNF-α activates RELA expression via TNFRSF1B to upregulate OPA1 expression and inhibit chondrogenic differentiation of human adipose stem cells

BACKGROUND

Tumor necrosis factor-alpha (TNF-α), one of the pro-inflammatory cytokines mediating the local inflammatory process in joints, inhibits cartilage formation and has a detrimental effect on stem cell-based cartilage regeneration for the treatment of osteoarthritis (OA). However, the mechanisms behind this inhibitory effect are still poorly understood. Mitochondrial morphological changes mediated by mitochondrial fusion and fission are highly plastic, are quite sensitive to environmental stimuli and play a crucial role in maintaining cell structure and function. In our study, chondrogenic differentiated human adipose stem cells (hADSCs) were exposed to TNF-α and the effect of TNF-α on the ability of hADSCs to chondrogenic differentiate and on mitochondrial fusion and fission was observed and analyzed. The aim was to investigate the role and mechanisms of mitochondrial fusion and fission regulation in the chondrogenic differentiation of hADSCs under normal conditions and under exposure to TNF-α.

METHODS

We used flow cytometry to identify hADSCs immunophenotypes CD29, CD44, CD34, CD45, and HLA-DR. Alcian blue staining and Sirius red staining were used to observe the formation of proteoglycans and collagen during the chondrogenic differentiation of hADSCs, respectively. The mRNA and protein expression levels of the cartilage formation marker SOX9, type II collagen (COL2A1), and Aggrecan were measured by real-time fluorescent quantitative PCR (RT-qPCR) and western blot, respectively. The fluorescent probes MitoTracker® Red CMXRos and JC-1 were used to visualize mitochondria morphology and detect mitochondrial membrane electricity (MMP). Affymetrix PrimeView™ chips were used for gene expression profiling.

RESULTS

The results showed that the chondrogenic differentiation of hADSCs was inhibited in the presence of TNF-α that optic atrophy 1 (OPA1) expression was significantly upregulated and mitochondria were prolonged and interconnected during this process. Gene microarray and RT-qPCR data showed that the presence of TNF-α led to increased expression of TNFα receptor 2 (TNFRSF1B) and RELA during chondrogenic differentiation of hADSCs.

CONCLUSIONS

TNF-α inhibits chondrogenic differentiation of human adipose stem cells by activating RELA expression through TNFRSF1B upregulating OPA1 expression thereby increasing mitochondrial fusion.

The Migration and the Fate of Dental Pulp Stem Cells

Human dental pulp stem cells (hDPSCs) are adult mesenchymal stem cells (MSCs) obtained from dental pulp and derived from the neural crest. They can differentiate into odontoblasts, osteoblasts, chondrocytes, adipocytes and nerve cells, and they play a role in tissue repair and regeneration. In fact, DPSCs, depending on the microenvironmental signals, can differentiate into odontoblasts and regenerate dentin or, when transplanted, replace/repair damaged neurons. Cell homing depends on recruitment and migration, and it is more effective and safer than cell transplantation. However, the main limitations of cell homing are the poor cell migration of MSCs and the limited information we have on the regulatory mechanism of the direct differentiation of MSCs. Different isolation methods used to recover DPSCs can yield different cell types. To date, most studies on DPSCs use the enzymatic isolation method, which prevents direct observation of cell migration. Instead, the explant method allows for the observation of single cells that can migrate at two different times and, therefore, could have different fates, for example, differentiation and self-renewal. DPSCs use mesenchymal and amoeboid migration modes with the formation of lamellipodia, filopodia and blebs, depending on the biochemical and biophysical signals of the microenvironment. Here, we present current knowledge on the possible intriguing role of cell migration, with particular attention to microenvironmental cues and mechanosensing properties, in the fate of DPSCs.

Human Mesenchymal Stromal Cells Derived from Perinatal Tissues: Sources, Characteristics and Isolation Methods

Mesenchymal stromal/stem cells (MSCs) derived from perinatal tissues have become indispensable sources for clinical applications due to their superior properties, ease of accessibility and minimal ethical concerns. MSCs isolated from different placenta (PL) and umbilical cord (UC) compartments exhibit great potential for stem cell-based therapies. However, their biological activities could vary due to tissue origins and differences in differentiation potentials. This review provides an overview of MSCs derived from various compartments of perinatal tissues, their characteristics and current isolation methods. Factors affecting the yield and purity of MSCs are also discussed as they are important to ensure consistent and unlimited supply for regenerative medicine and tissue engineering.

Transcriptome profiles associated with human periodontal ligament differentiation

OBJECTIVES

Tissue differentiation is regulated by transcription factors. This study aimed to identify candidate transcription factors that induce periodontal ligament (PDL) cell differentiation in human pluripotent stem cells (hPSCs).

METHODS

Human PDL tissues were scraped from the root surfaces of extracted teeth for orthodontic treatment and cultured using the explant culture method. We used RNA-seq to generate gene expression profiles of third-passage PDL cells and compared them with those of undifferentiated human induced pluripotent stem cells (hiPSCs) and human embryonic stem cell (hESC)-derived neural crest (NC) cells (publicly available data).

RESULTS

Primary cultured PDL cells exhibited a spindle-shaped fibroblast-like appearance and the gene expression of several PDL cell-specific markers. The gene expression profiles of PDL cells were relatively similar to those of hESC-derived NC cells but not those of undifferentiated hiPSCs. Thirty-seven transcription factors were identified as upregulated genes in PDL cells. Pathway analysis showed that differentially expressed genes were enriched in several functional groups and pathways, including the SMAD 2/3 nuclear pathway.

CONCLUSIONS

We identified 37 upregulated transcription genes in primary cultured PDL cells compared with hESC-derived NC cells. Regulating these genes and the SMAD signaling pathway may be promising ways to induce PDL cells from hPSC-derived NC cells.

The in vitro treatment of mesenchymal stem cells for colorectal cancer cells

Colorectal cancer is the most common tumor of the gastrointestinal system. The conventional treatment options for colorectal cancer are troublesome for both patients and clinicians. Recently, mesenchymal stem cells (MSCs) have been the novel focus for cell therapy due to their migration to tumor sites. In this study, the apoptotic effect of MSCs on colorectal cancer cell lines has been aimed. HCT-116 and HT-29 were selected as the colorectal cancer cell lines. Human umbilical cord blood and Wharton's jelly were used as mesenchymal stem cell sources. To discriminate against the apoptotic effect of MSC on cancer, we also used peripheral blood mononuclear cells (PBMC) as a healthy control group. Cord blood-MSC and PBMC were obtained by ficoll-paque density gradient, and Wharton's jelly-MSC by explant method. Transwell co-culture systems were used as cancer cells or PBMC/MSCs at ratios of 1/5 and 1/10, with incubation times of 24 h and 72 h. The Annexin V/PI-FITC-based apoptosis assay was performed by flow cytometry. Caspase-3 and HTRA2/Omi proteins were measured by ELISA. For both ratios in both cancer cells, it was found that the apoptotic effect of Wharton's jelly-MSC was significantly higher in 72-h incubations (p < 0.006), whereas the effect of cord blood mesenchymal stem cell in 24-h incubations were higher (p < 0.007). In this study, we showed that human cord blood and tissue-derived MSCs treatment led to colorectal cancers to apoptosis. We anticipate that further in vivo studies may shed light on the apoptotic effect of MSC.

NFATC1 and NFATC2 expression patterns in human osteochondromas

Background

Our previous study in genetic mouse models found that NFATc1 and NFATc2 suppress osteochondroma formation from entheseal progenitors. However, it remains unclear whether NFAT signaling is also involved in human osteochondromagenesis. As the first step in addressing this question, the current study aimed to determine the expression patterns of NFATC1 and NFATC2 in human osteochondroma samples.

Methods

Immunohistochemistry (IHC) was used to examine and analyze NFATC1 and NFATC2 expression in human osteochondroma samples. The human periosteum was used to map the expression of NFATC1 under physiological conditions by IHC. Furthermore, human periosteal progenitors were isolated and identified from the periosteal tissues of bone fracture healing patients. The expression of NFATC1 in human periosteal progenitors was characterized by Western blotting compared to human bone marrow stromal cells (BMSC).

Results

The IHC results showed that the expression of NFATC1 was undetectable in most human osteochondromas cells, and only a small proportion of osteochondroma cells, especially clonally grown chondrocytes, showed positive staining of NFATC1. NFATC2 expression was also undetectable in most chondrocytes in human osteochondromas. The mouse and human periosteum showed a comparable ratio of NFATC1 positive cells (9.56 ± 0.80% vs 11.04 ± 2.05%, P = 0.3101). Furthermore, Western blotting analysis revealed that NFATC1 expression was highly enriched in human periosteal progenitors compared to BMSC.

Conclusions

NFATC1 and NFATC2 are undetectable in most human osteochondroma chondrocytes. The expression pattern of NFATC1 in human osteochondromas and the normal periosteum suggests that NFAT signaling could be suppressed during human osteochondromagenesis.

Approaches for the isolation and long-term expansion of pericytes from human and animal tissues

Pericytes surround capillaries in every organ of the human body. They are also present around the vasa vasorum, the small blood vessels that supply the walls of larger arteries and veins. The clinical interest in pericytes is rapidly growing, with the recognition of their crucial roles in controlling vascular function and possible therapeutic applications in regenerative medicine. Nonetheless, discrepancies in methods used to define, isolate, and expand pericytes are common and may affect reproducibility. Separating pure pericyte preparations from the continuum of perivascular mesenchymal cells is challenging. Moreover, variations in functional behavior and antigenic phenotype in response to environmental stimuli make it difficult to formulate an unequivocal definition of bona fide pericytes. Very few attempts were made to develop pericytes as a clinical-grade product. Therefore, this review is devoted to appraising current methodologies' pros and cons and proposing standardization and harmonization improvements. We highlight the importance of developing upgraded protocols to create therapeutic pericyte products according to the regulatory guidelines for clinical manufacturing. Finally, we describe how integrating RNA-seq techniques with single-cell spatial analysis, and functional assays may help realize the full potential of pericytes in health, disease, and tissue repair.

Establishment and characterization of a new fibroblast-like cell line from the skin of a vertebrate model, zebrafish (Danio rerio)

BACKGROUND

The available fully sequenced genome and genetic similarities compared to humans make zebrafish a prominent in vitro vertebrate model for drug discovery & screening, toxicology, and radiation biology. Zebrafish also possess well developed immune systems which is ideal for studying infectious diseases. Fish skin confers immunity by serving as a physical barrier against the invading pathogens in the aquatic habitat. Therefore in vitro models from the skin tissue of zebrafish help to study the physiology, functional genes in vitro, wound healing, and pathogenicity of microbes. Hence the study aimed to develop and characterize a skin cell line from the wild-type zebrafish Danio rerio.

METHODS AND RESULTS

A novel cell line designated as DRS (D. rerio skin) was established and characterized from the skin tissue of wild-type zebrafish, D. rerio, by the explant technique. The cells thrived well in the Leibovitz's -15 medium supplemented with 15% FBS and routinely passaged at regular intervals. The DRS cells mainly feature fibroblast-like morphology. The culture conditions of the cells were determined by incubating the cells at varying concentrations of FBS and temperature; the optimum was 15% FBS and 28 °C, respectively. Cells were cryopreserved and revived with 70-75% viability at different passage levels. Two extracellular products from bacterial species Aeromonas hydrophila and Edwardsiella tarda were tested and found toxic to the DRS cells. Mitochondrial genes, namely COI and 16S rRNA PCR amplification and partial sequencing authenticated the species of origin of cells. The modal diploid (2n) chromosome number of the cells was 50. The cell line DRS was found to be free from mycoplasma. The cells were transfected with pMaxGFP plasmid and tested positive for green fluorescence at 24-48 h post-transfection.

CONCLUSION

The findings from this study thus confirm the usefulness of the developed cell line in bacterial susceptibility and transgene expression studies.

A Cell Culture Method for the Isolation and Study of Primary Human Dental Pulp Cells

Primary human dental pulp cell (HDPC) cultures contain dental pulp stem cell (DPSC) populations. DPSCs are multipotent mesenchymal cells residing inside the dental pulp where they can contribute to the regenerative potential of this and other tissues throughout the body. These cells are promising tools for cell-based therapies, including regenerative endodontic procedures. HDPCs can be readily isolated and expanded from extracted teeth either by the dental tissue explant method or enzymatic digestion method. This chapter describes the explant method, whereby cells outgrow from dissected pulp tissue, to generate HDPC cultures. We also provide protocols for HDPC passaging, cryopreservation, and basic immunocytochemical characterization.

Mesenchymal stem cell therapy for neurological disorders: The light or the dark side of the force?

Neurological disorders are recognized as major causes of death and disability worldwide. Because of this, they represent one of the largest public health challenges. With awareness of the massive burden associated with these disorders, came the recognition that treatment options were disproportionately scarce and, oftentimes, ineffective. To address these problems, modern research is increasingly looking into novel, more effective methods to treat neurological patients; one of which is cell-based therapies. In this review, we present a critical analysis of the features, challenges, and prospects of one of the stem cell types that can be employed to treat numerous neurological disorders-mesenchymal stem cells (MSCs). Despite the fact that several studies have already established the safety of MSC-based treatment approaches, there are still some reservations within the field regarding their immunocompatibility, heterogeneity, stemness stability, and a range of adverse effects-one of which is their tumor-promoting ability. We additionally examine MSCs' mechanisms of action with respect to in vitro and in vivo research as well as detail the findings of past and ongoing clinical trials for Parkinson's and Alzheimer's disease, ischemic stroke, glioblastoma multiforme, and multiple sclerosis. Finally, this review discusses prospects for MSC-based therapeutics in the form of biomaterials, as well as the use of electromagnetic fields to enhance MSCs' proliferation and differentiation into neuronal cells.

Development of hydroxyapatite-coated nonwovens for efficient isolation of somatic stem cells from adipose tissues

Adipose-derived stem cells (ASCs) are an attractive cell source for cell therapy. Despite the increasing number of clinical applications, the methodology for ASC isolation is not optimized for every individual. In this study, we developed an effective material to stabilize explant cultures from small-fragment adipose tissues.

Methods

Polypropylene/polyethylene nonwoven sheets were coated with hydroxyapatite (HA) particles. Adipose fragments were then placed on these sheets, and their ability to trap tissue was monitored during explant culture. The yield and properties of the cells were compared to those of cells isolated by conventional collagenase digestion.

Results

Hydroxyapatite-coated nonwovens immediately trapped adipose fragments when placed on the sheets. The adhesion was stable even in culture media, leading to cell migration and proliferation from the tissue along with the nonwoven fibers. A higher fiber density further enhanced cell growth. Although cells on nonwoven explants could not be fully collected with cell dissociation enzymes, the cell yield was significantly higher than that of conventional monolayer culture without impacting stem cell properties.

Conclusions

Hydroxyapatite-coated nonwovens are useful for the effective primary explant culture of connective tissues without enzymatic cell dissociation.

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Hydroxyapatite-coated nonwovens enable explant culture of adipose tissue.

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ASCs migrated and proliferated from the tissue explants along the fibers in nonwovens.

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Nonwoven explants had significantly higher cell yield than conventional culture.

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Nonwoven culture did not impact stem cell properties of ASCs.

Human nasal olfactory stem cells, purified as advanced therapy medicinal products, improve neuronal differentiation

BACKGROUND

Olfactory ecto-mesenchymal stem cells (OE-MSC) are mesenchymal stem cells derived from the lamina propria of the nasal mucosa. They display neurogenic and immunomodulatory properties and were shown to induce recovery in animal models of spinal cord trauma, hearing loss, Parkinsons's disease, amnesia, and peripheral nerve injury. As a step toward clinical practice, we sought to (i) devise a culture protocol that meets the requirements set by human health agencies and (ii) assess the efficacy of stem cells on neuron differentiation.

METHODS

Nasal olfactory mucosa biopsies from three donors were used to design and validate the good manufacturing process for purifying stem cells. All processes and procedures were performed by expert staff from the cell therapy laboratory of the public hospital of Marseille (AP-HM), according to aseptic handling manipulations. Premises, materials and air were kept clean at all times to avoid cross-contamination, accidents, or even fatalities. Purified stem cells were cultivated for 24 or 48 h and conditioned media were collected before being added to the culture medium of the neuroblastoma cell line Neuro2a.

RESULTS

Compared to the explant culture-based protocol, enzymatic digestion provides higher cell numbers more rapidly and is less prone to contamination. The use of platelet lysate in place of fetal calf serum is effective in promoting higher cell proliferation (the percentage of CFU-F progenitors is 15.5%), with the optimal percentage of platelet lysate being 10%. Cultured OE-MSCs do not show chromosomal rearrangement and, as expected, express the usual phenotypic markers of mesenchymal stem cells. When incorporated in standard culture medium, the conditioned medium of purified OE-MSCs promotes cell differentiation of Neuro2a neuroblastoma cells.

CONCLUSION

We developed a safer and more efficient manufacturing process for clinical grade olfactory stem cells. With this protocol, human OE-MSCs will soon be used in a Phase I clinical based on their autologous transplantation in digital nerves with a neglected injury. However, further studies are required to unveil the underlying mechanisms of action.

Effects of Human Deciduous Dental Pulp-Derived Mesenchymal Stem Cell-Derived Conditioned Medium on the Metabolism of HUVECs, Osteoblasts, and BMSCs

In this study, we assessed the effects of human deciduous dental pulp-derived mesenchymal stem cell-derived conditioned medium (SHED-CM) on the properties of various cell types. The effects of vascular endothelial growth factor (VEGF) in SHED-CM on the luminal architecture, proliferative ability, and angiogenic potential of human umbilical vein endothelial cells (HUVECs) were determined. We also investigated the effects of SHED-CM on the proliferation of human-bone-marrow mesenchymal stem cells (hBMSCs) and mouse calvarial osteoblastic cells (MC3T3-E1) as well as the expression of ALP, OCN, and RUNX2. The protein levels of ALP were examined using Western blot analysis. VEGF blockade in SHED-CM suppressed the proliferative ability and angiogenic potential of HUVECs, indicating that VEGF in SHED-CM contributes to angiogenesis. The culturing of hBMSCs and MC3T3-E1 cells with SHED-CM accelerated cell growth and enhanced mRNA expression of bone differentiation markers. The addition of SHED-CM enhanced ALP protein expression in hBMSCs and MT3T3-E1 cells compared with that of the 0% FBS group. Furthermore, SHED-CM promoted the metabolism of HUVECs, MC3T3-E1 cells, and hBMSCs. These findings indicate the potential benefits of SHED-CM in bone tissue regeneration.

Characterization of a Stemness-Optimized Purification Method for Human Dental-Pulp Stem Cells: An Approach to Standardization

Human dental pulp stem cells (hDPSCs) are promising for oral/craniofacial regeneration, but their purification and characterization is not yet standardized. hDPSCs from three donors were purified by magnetic activated cell sorting (MACS)-assisted STRO-1-positive cell enrichment (+), colony derivation (c), or a combination of both (c/+). Immunophenotype, clonogenicity, stemness marker expression, senescence, and proliferation were analyzed. Multilineage differentiation was assessed by qPCR, immunohistochemistry, and extracellular matrix mineralization. To confirm the credibility of the results, repeated measures analysis and post hoc p-value adjustment were applied. All hDPSC fractions expressed STRO-1 and were similar for several surface markers, while their clonogenicity and expression of CD10/44/105/146, and 166 varied with the purification method. (+) cells proliferated significantly faster than (c/+), while (c) showed the highest increase in metabolic activity. Colony formation was most efficient in (+) cells, which also exhibited the lowest cellular senescence. All hDPSCs produced mineralized extracellular matrix. Regarding osteogenic induction, (c/+) revealed a significant increase in mRNA expression of COL5A1 and COL6A1, while osteogenic marker genes were detected at varying levels. (c/+) were the only population missing BDNF gene transcription increase during neurogenic induction. All hDPSCs were able to differentiate into chondrocytes. In summary, the three hDPSCs populations showed differences in phenotype, stemness, proliferation, and differentiation capacity. The data suggest that STRO-1-positive cell enrichment is the optimal choice for hDPSCs purification to maintain hDPSCs stemness. Furthermore, an (immuno) phenotypic characterization is the minimum requirement for quality control in hDPSCs studies.

Transplanted hair follicle mesenchymal stem cells alleviated small intestinal ischemia–reperfusion injury via intrinsic and paracrine mechanisms in a rat model

Background: Small intestinal ischemia-reperfusion (IR) injury is a common intestinal disease with high morbidity and mortality. Mesenchymal stem cells (MSCs) have been increasingly used in various intestinal diseases. This study aimed to evaluate the therapeutic effect of hair follicle MSCs (HFMSCs) on small intestinal IR injury.

Methods: We divided Sprague–Dawley rats into three groups: the sham group, IR group and IR + HFMSCs group. A small intestinal IR injury rat model was established by clamping of the superior mesenteric artery (SMA) for 30 min and reperfusion for 2 h. HFMSCs were cultured in vitro and injected into the rats through the tail vein. Seven days after treatment, the intrinsic homing and differentiation characteristics of the HFMSCs were observed by immunofluorescence and immunohistochemical staining, and the paracrine mechanism of HFMSCs was assessed by Western blotting and enzyme-linked immunosorbent assay (ELISA).

Results: A small intestinal IR injury model was successfully established. HFMSCs could home to damaged sites, express proliferating cell nuclear antigen (PCNA) and intestinal stem cell (ISC) markers, and promote small intestinal ISC marker expression. The expression levels of angiopoietin-1 (ANG1), vascular endothelial growth factor (VEGF) and insulin growth factor-1 (IGF1) in the IR + HFMSCs group were higher than those in the IR group. HFMSCs could prevent IR-induced apoptosis by increasing B-cell lymphoma-2 (Bcl-2) expression and decreasing Bcl-2 homologous antagonist/killer (Bax) expression. Oxidative stress level detection showed that the malondialdehyde (MDA) content was decreased, while the superoxide dismutase (SOD) content was increased in the IR + HFMSCs group compared to the IR group. An elevated diamine oxidase (DAO) level reflected the potential protective effect of HFMSCs on the intestinal mucosal barrier.

Conclusion: HFMSCs are beneficial to alleviate small intestinal IR injury through intrinsic homing to the small intestine and by differentiating into ISCs, via a paracrine mechanism to promote angiogenesis, reduce apoptosis, regulate the oxidative stress response, and protect intestinal mucosal function potentially. Therefore, this study suggests that HFMSCs serve as a new option for the treatment of small intestinal IR injury.

Corneal Regeneration Using Adipose-Derived Mesenchymal Stem Cells

Adipose-derived stem cells are a subtype of mesenchymal stem cell that offers the important advantage of being easily obtained (in an autologous manner) from low invasive procedures, rendering a high number of multipotent stem cells with the potential to differentiate into several cellular lineages, to show immunomodulatory properties, and to promote tissue regeneration by a paracrine action through the secretion of extracellular vesicles containing trophic factors. This secretome is currently being investigated as a potential source for a cell-free based regenerative therapy for human tissues, which would significantly reduce the involved costs, risks and law regulations, allowing for a broader application in real clinical practice. In the current article, we will review the existing preclinical and human clinical evidence regarding the use of such adipose-derived mesenchymal stem cells for the regeneration of the three main layers of the human cornea: the epithelium (derived from the surface ectoderm), the stroma (derived from the neural crest mesenchyme), and the endothelium (derived from the neural crest cells).

Mesenchymal stem cells improve liver fibrosis and protect hepatocytes by promoting microRNA-148a-5p-mediated inhibition of Notch signaling pathway

Background

Mesenchymal stem cells (MSCs) are considered to be a potential therapeutic tool for liver fibrosis. Inhibiting the activation of hepatic stellate cells (HSCs) and protecting hepatocytes are important mechanisms for the anti-fibrotic effect of MSCs. However, how MSCs inhibit liver fibrosis by regulating the expression of microRNAs (miRNAs) has not been fully clarified.

Methods

Transforming growth factor-β1 (TGF-β1)-activated HSCs LX-2 were single cultured or co-cultured with human umbilical cord mesenchymal stem cells (HUC-MSCs). High-throughput sequencing was used to evaluate the differentially expressed microRNAs (DEMs) between the two groups. Quantitative real-time PCR (qRT-PCR), Western blot, and transfection experiments were used to investigate and screen the most significantly up-regulated DEM. Bioinformatics analysis was used to predict the target mRNAs and the potential functions of the DEM. The possible mechanism of HUC-MSCs against liver fibrosis was analyzed by co-culture experiment of HUC-MSCs with LX-2 cells, and HUC-MSCs treatment of Bile duct ligation (BDL)-induced liver fibrosis in mice. Finally, the mechanism of the DEM regulating liver fibrosis was confirmed in human liver fibrosis specimens.

Results

MicroRNA-148a-5p (miR-148a-5p) was the most significantly up-regulated DEM in activated LX-2 cells co-cultured with HUC-MSCs compared with LX-2 cells single cultured. Up-regulation of the expression of miR-148a-5p in activated LX-2 cells could significantly inhibit the expression of hepatic fibrosis markers α-SMA and Col1α1. Notch2 was one target gene of miR-148a-5p. Co-cultured with HUC-MSCs could inhibit the activation of LX-2 cells by inhibiting the expression of the Notch2 and the Notch signaling pathway. In addition, HUC-MSCs treatment could up-regulate the expression of miR-148a-5p in liver tissue and hepatocytes, promote the proliferation and avoid the apoptosis of hepatocytes, and reduce the degree of fibrosis by inhibiting expression of the Notch2 and the Notch signaling pathway in BDL-induced liver fibrosis mice. Moreover, miR-148a-5p was down-regulated and Notch2 was up-regulated in fibrotic human liver tissues compared with the normal livers.

Conclusions

HUC-MSCs treatment could inhibit HSCs activation, protect hepatocytes, and alleviate BDL-induced liver fibrosis in mice by up-regulating the expression of miR-148-5p and inhibiting the Notch signaling pathway. The down-regulation of miR-148-5p and up-regulation of Notch2 could be used as biomarkers to monitor the progression of liver fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03030-8.

Human Umbilical Cord Mesenchymal Stem Cells Encapsulated with Pluronic F-127 Enhance the Regeneration and Angiogenesis of Thin Endometrium in Rat via Local IL-1β Stimulation

Thin endometrium (< 7 mm) could cause low clinical pregnancy, reduced live birth, increased spontaneous abortion, and decreased birth weight. However, the treatments for thin endometrium have not been well developed. In this study, we aim to determine the role of Pluronic F-127 (PF-127) encapsulation of human umbilical cord mesenchymal stem cells (hUC-MSCs) in the regeneration of thin endometrium and its underlying mechanism. Thin endometrium rat model was created by infusion of 95% ethanol. Thin endometrium modeled rat uterus were treated with saline, hUC-MSCs, PF-127, or hUC-MSCs plus PF-127 separately. Regenerated rat uterus was measured for gene expression levels of angiogenesis factors and histological morphology. Angiogenesis capacity of interleukin-1 beta (IL-1β)-primed hUC-MSCs was monitored via quantitative polymerase chain reaction (q-PCR), Luminex assay, and tube formation assay. Decreased endometrium thickness and gland number and increased inflammatory factor IL-1β were achieved in the thin endometrium rat model. Embedding of hUC-MSCs with PF-127 could prolong the hUC-MSCs retaining, which could further enhance endometrium thickness and gland number in the thin endometrium rat model via increasing angiogenesis capacity. Conditional medium derived from IL-1β-primed hUC-MSCs increased the concentration of angiogenesis factors (basic fibroblast growth factor (bFGF), vascular endothelial growth factors (VEGF), and hepatocyte growth factor (HGF)). Improvement in the thickness, number of glands, and newly generated blood vessels could be achieved by uterus endometrium treatment with PF-127 and hUC-MSCs transplantation. Local IL-1β stimulation-primed hUC-MSCs promoted the release of angiogenesis factors and may play a vital role on thin endometrium regeneration.

Resistin Modulates Low-Density Lipoprotein Cholesterol Uptake in Human Placental Explants via PCSK9

Maternal metabolic status influences pregnancy and, consequently, the perinatal outcome. Resistin is a pro-inflammatory adipokine predominantly expressed and secreted by mononuclear cells, adipose tissue, and placental trophoblastic cells during pregnancy. Recently, we reported an inverse association between maternal resistin levels and fetal low-density lipoprotein cholesterol (LDL-C). Then, in this work, we used a human placental explant model and the trophoblast cell line JEG-3 to evaluate whether resistin affects placental LDL-C uptake. Resistin exposure induced the transcription factor SREBP-2, LDLR, and PCSK9 mRNA expression, and changes at the protein level were confirmed by immunohistochemistry and Western blot. However, for LDLR, the changes were not consistent between mRNA and protein levels. Using a labeled LDL-cholesterol (BODIPY FL LDL), uptake assay demonstrated that the LDL-C was significantly decreased in placental explants exposed to a high dose of resistin and a lesser extent in JEG-3 cells. In summary, resistin induces PCSK9 expression in placental explants and JEG-3 cells, which could be related to negative regulation of the LDLR by lysosomal degradation. These findings suggest that resistin may significantly regulate the LDL-C uptake and transport from the maternal circulation to the fetus, affecting its growth and lipid profile.

A comparison of isolation and culture protocols for human amniotic mesenchymal stem cells

The successful translation of mesenchymal stem cells (MSCs) from bench to bedside is predicated upon their regenerative capabilities and immunomodulatory potential. Many challenges still exist in making MSCs a viable and cost-effective therapeutic option, due in part to the challenges of sourcing MSCs from adult tissues and inconsistencies in the characterization of MSCs. In many cases, adult MSC collection is an invasive procedure, and ethical concerns and age-related heterogeneity further complicate obtaining adult tissue derived MSCs at the scales needed for clinical applications. Alternative adult sources, such as post-partum associated tissues, offer distinct advantages to overcome these challenges. However, successful therapeutic applications rely on the efficient ex-vivo expansion of the stem cells while avoiding any culture-related phenotypic alterations, which requires optimized and standardized isolation, culture, and cell preservation methods. In this review, we have compared the isolation and culture methods for MSCs originating from the human amniotic membrane (hAMSCs) of the placenta to identify the elements that support the extended subculture potential of hAMSCs without compromising their immune-privileged, pluripotent regenerative potential.Abbreviations:AM: Human amniotic membrane; ASCs: Adipose tissue-derived stem cells; BM-MSCs: Bone marrow-mesenchymal stem cells; DMEM: Dulbecco's modified eagle medium; DT: Doubling time; EMEM: Eagle's modified essential medium; ESCM: Embryonic stem cell markers; ESCs: Embryonic stem cells; hAECs: Human amniotic epithelial cells; hAMSCs: Human amniotic mesenchymal stem cells; HLA: Human leukocyte antigen; HM: Hematopoietic markers; IM: Immunogenicity markers; MHC: Major histocompatibility complex; MSCs: Mesenchymal stem cells; MCSM: Mesenchymal cell surface markers; Nanog: NANOG homeobox; Oct: Octamer binding transcription factor 4; P: Passage; PM: Pluripotency markers; STRO-1: Stromal precursor antigen-1; SCP: Subculture potential; Sox-2: Sry-related HMG box gene 2; SSEA-4: Stage-specific embryonic antigen; TRA: Tumor rejection antigen.

Development and characterization of a new gill cell line from the striped catfish, Pangasianodon hypophthalmus (Sauvage, 1878)

Cell lines as an in vitro model developed from different target organs of fish find their use in virus susceptibility, cytotoxicity, gene expression studies. The striped catfish, Pangasianodon hypophthalmus, is one of the main species in aquaculture, especially in Southeast Asian countries like Thailand, Indonesia, China, India, Bangladesh, and Vietnam. The present study reports the development of a new permanent cell line from the gills of P. hypophthalmus designated as PHG and its application in toxicological research. Leibovitz's L-15 cell culture medium supplemented with 15% fetal bovine serum (FBS) was used to maintain cell line PHG. The morphology of the PHG cell line was observed fibroblastic-like. PHG cells grew well at varying temperatures ranging from 24 to 30 °C with an optimum temperature of 28 °C. The PHG cell line was characterized using a sequence of mitochondrial cytochrome C oxidase subunit I, which authenticated the species of origin of the cell line. The cell line was transfected with a pEGFP-C1 plasmid, and the transfection reporter gene was successfully expressed 48 h post-transfection with 9% transfection efficiency. The toxicity assessment of two organophosphate pesticides, chlorpyrifos, and malathion using the PHG cell line revealed that the two organophosphate pesticides were cytotoxic to the cell line at varying concentrations.

Arthroscopic Rotator Cuff Repair Augmentation With Autologous Microfragmented Lipoaspirate Tissue Is Safe and Effectively Improves Short-term Clinical and Functional Results: A Prospective Randomized Controlled Trial With 24-Month Follow-up

BACKGROUND

Autologous microfragmented lipoaspirate tissue has been recently introduced in orthopaedics as an easily available source of nonexpanded adipose-derived mesenchymal stem cells. Autologous microfragmented lipoaspirate tissue is expected to create a suitable microenvironment for tendon repair and regeneration. Rotator cuff tears show a high incidence of rerupture and represent an ideal target for nonexpanded mesenchymal stem cells.

PURPOSE

To evaluate the safety and efficacy of autologous lipoaspirate tissue in arthroscopic rotator cuff repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Consecutive patients referring to the investigation center for surgical treatment of magnetic resonance imaging-confirmed degenerative posterosuperior rotator cuff tears were assessed for eligibility. Those who were included were randomized to receive a single-row arthroscopic rotator cuff repair, followed by intraoperative injection of autologous microfragmented adipose tissue processed with an enzyme-free technology (treatment group) or not (control group). Clinical follow-up was conducted at 3, 6, 12, 18, and 24 months; at 18 months after surgery, magnetic resonance imaging of the operated shoulder was obtained to assess tendon integrity and rerupture rate.

RESULTS

An overall 177 patients were screened, and 44 (22 per group) completed the 24-month follow-up. A statistically significant difference in favor of the treatment group in terms of Constant-Murley score emerged at the primary endpoint at 6-month follow-up (mean ± SD; control group, 76.66 ± 10.77 points; treatment group, 82.78 ± 7.00 points; P = .0050). No significant differences in clinical outcome measures were encountered at any of the other follow-up points. No significant differences emerged between the groups in terms of rerupture rate, complication rate, and number of adverse events.

CONCLUSION

This prospective randomized controlled trial demonstrated that the intraoperative injection of autologous microfragmented adipose tissue is safe and effective in improving short-term clinical and functional results after single-row arthroscopic rotator cuff repair.

REGISTRATION

NCT02783352 (ClinicalTrials.gov identifier).

Long-term explant culture: an improved method for consistently harvesting homogeneous populations of keloid fibroblasts

Explant culture is a more suitable method than enzyme digestion for the isolation of keloid fibroblasts (KFs), but it has a longer isolation period. In this study, we propose a long-term explant culture method. Unlike in the conventional explant culture method, we continued culturing explants to isolate KFs rather than discarding them during passage. We demonstrated that keloid explants could be cultured for more than 4 months to continuously yield enriched KFs, and the KFs from the repeatedly cultured explants had shorter isolation times. The biological behavior and fibrotic phenotypic characteristics of the KFs from the explants cultured long term were investigated, and no statistical differences were found compared with the KFs from the original explants. In conclusion, the long-term explant culture method was shown to be efficient for harvesting a large, homogeneous population of KFs. The high efficiency as well as ease of operation and sample saving make this method convenient for researchers working with KFs.

A Robust and Highly Efficient Approach for Isolation of Mesenchymal Stem Cells From Wharton's Jelly for Tissue Repair

Mesenchymal stem cells derived from umbilical cord Wharton's Jelly (WJ-MSCs) are emerging as promising therapeutics for a variety of diseases due to their ability of regeneration and immunomodulation, and their non-tumorigenic and non-immunogenic properties. Although multiple protocols have been developed for WJ-MSC isolation, insufficient cell numbers, heterogeneous cell population, and variations in procedures between different laboratories impede further clinical applications. Here, we compared six widely used WJ-MSC isolation methods regarding cell morphology, yield, purity, proliferation rate, and differentiation potential. Based on these analyses, we identified that the inefficiency of the extracellular matrix digestion results in low cell yield. Thus, we developed a new method called "Mince-Soak-Digest (MSD)" to isolate MSCs from WJ by incorporating a soaking step to facilitate the digestion of the extracellular matrix and release of the cells. Our newly developed method generates significantly higher cell yield (4- to 10-fold higher) than six widely used methods that we tested with high purity and consistency. Importantly, by transplantation of WJ-MSCs to the rat uterus, we repair the endometrial injury and restore the fertility of the rats. In conclusion, our results provide a robust and highly efficient approach for the isolation of WJ-MSCs to restore injured tissue. The higher efficiency of MSD assures the abundance of WJ-MSCs for clinical applications. Furthermore, the reliability of MSD contributes to the standardization of WJ-MSC isolation, which eliminates the discrepancies due to isolation procedures, thus facilitating the evaluation of the efficacy of WJ-MSCs across various human clinical applications.

Analysis of the Cultured Meat Production System in Function of Its Environmental Footprint: Current Status, Gaps and Recommendations

Cultured meat has been presented as an environmentally friendlier option to conventional meat, but due to the limited data, the studies related to its performance are scarce and based on hypothetical production processes. This work provides a short literature review of the published environmental assessments of cultured meat. The main findings of this critical analysis showed that the lack of real data related to cultured meat decreased the level of accuracy of each study. The missing environmental profile of the process itself, including the proliferation and differentiation phases in bioreactors, along with key ingredients such as growth factors and other recombinant proteins, increase the difficulty of achieving reliable conclusions. In order to bridge the highlighted gaps, a complete production system is modelled and analysed from an engineering and life-cycle perspective. Furthermore, an overview of the supply chains of different products used in the process is provided, together with recommendations on how they should be considered in future life-cycle assessments. In essence, this work provides a structured pathway for upcoming consistent environmental assessments in this field, with the objective of setting the basis to understand the potential of cultured meat.

Mesenchymal Stem/Stromal Cells Derived from Human and Animal Perinatal Tissues-Origins, Characteristics, Signaling Pathways, and Clinical Trials

Mesenchymal stem/stromal cells (MSCs) are currently one of the most extensively researched fields due to their promising opportunity for use in regenerative medicine. There are many sources of MSCs, of which cells of perinatal origin appear to be an invaluable pool. Compared to embryonic stem cells, they are devoid of ethical conflicts because they are derived from tissues surrounding the fetus and can be safely recovered from medical waste after delivery. Additionally, perinatal MSCs exhibit better self-renewal and differentiation properties than those derived from adult tissues. It is important to consider the anatomy of perinatal tissues and the general description of MSCs, including their isolation, differentiation, and characterization of different types of perinatal MSCs from both animals and humans (placenta, umbilical cord, amniotic fluid). Ultimately, signaling pathways are essential to consider regarding the clinical applications of MSCs. It is important to consider the origin of these cells, referring to the anatomical structure of the organs of origin, when describing the general and specific characteristics of the different types of MSCs as well as the pathways involved in differentiation.