Phenotypic changes of adult porcine mesenchymal stem cells induced by prolonged passaging in culture

Osteopontin Rejuvenates Senescent Adipose-Derived Stem Cells and Restores their Bone Tissue Regenerative Function

The regenerative function of stem cells is compromised when the proportion of senescent stem cells increases with ageing advance. Therefore, combating stem cell senescence is of great importance for stem cell-based tissue engineering in the elderly, but remains largely unexplored. Osteopontin (OPN), a glycosylated phosphoprotein, is one of the key extracellular matrix molecules in bone tissue. OPN activates various signalling pathways and modulates cellular activities, including cell senescence. However, the role of OPN in stem cell senescence remains largely unknown. This study aims to investigate if OPN modulates cell senescence and bone regenerative function in human adipose-derived mesenchymal stem cells (ASCs), and to determine the underlying mechanisms. We first developed a senescent ASC model using serial passaging until passage 10 (P10), in which senescent cells were characterised by reduced proliferation and osteogenic differentiation capacity compared to P4 ASCs. The conditioned medium from P10 ASCs exhibited a diminished trophic effect on human osteoblasts (HOBs), compared to that from P4 ASCs. P10 ASCs on OPN-coated surface showed rejuvenated phenotype and enhanced osteogenic differentiation. The conditioned medium from P10 ASCs on OPN-coating improved trophic effects on HOBs. OPN regulated the morphology of senescent ASCs, transforming them from a more rounded and flattened cell shape to an elongated shape with a smaller area. These findings demonstrated the effects of OPN in restoring senescent ASCs functions, possibly through a mechanism that involves the modulation of cell morphology, indicating that OPN might hold a great potential for rejuvenating senescent stem cells and could potentially open a new venue for regenerating bone tissue in age-related diseases.

Recent Advances in Management of Neuropathic, Nociceptive, and Chronic Pain: A Narrative Review with Focus on Nanomedicine, Gene Therapy, Stem Cell Therapy, and Newer Therapeutic Options

PURPOSE OF REVIEW

This manuscript summarizes novel clinical and interventional approaches in the management of chronic, nociceptive, and neuropathic pain.

RECENT FINDINGS

Pain can be defined as a feeling of physical or emotional distress caused by an external stimulus. Pain can be grouped into distinct types according to characteristics including neuropathic pain, which is a pain caused by disease or lesion in the sensory nervous system; nociceptive pain, which is pain that can be sharp, aching, or throbbing and is caused by injury to bodily tissues; and chronic pain, which is long lasting or persisting beyond 6 months. With improved understanding of different signaling systems for pain in recent years, there has been an upscale of methods of analgesia to counteract these pathological processes. Novel treatment methods such as use of cannabinoids, stem cells, gene therapy, nanoparticles, monoclonal antibodies, and platelet-rich plasma have played a significant role in improved strategies for therapeutic interventions. Although many management options appear to be promising, extensive additional clinical research is warranted to determine best practice strategies in the future for clinicians.

Derivation and long-term maintenance of porcine skeletal muscle progenitor cells

Culture of muscle cells from livestock species has typically involved laborious enzyme-based approaches that yield heterogeneous populations with limited proliferative and myogenic differentiation capacity, thus limiting their use in physiologically-meaningful studies. This study reports the use of a simple explant culture technique to derive progenitor cell populations from porcine muscle that could be maintained and differentiated long-term in culture. Fragments of semitendinosus muscle from 4 to 8 week-old piglets (n = 4) were seeded on matrigel coated culture dishes to stimulate migration of muscle-derived progenitor cells (MDPCs). Cell outgrowths appeared within a few days and were serially passaged and characterised using RT-qPCR, immunostaining and flow cytometry. MDPCs had an initial mean doubling time of 1.4 days which increased to 2.5 days by passage 14. MDPC populations displayed steady levels of the lineage-specific markers, PAX7 and MYOD, up until at least passage 2 (positive immunostaining in about 40% cells for each gene), after which the expression of myogenic markers decreased gradually. Remarkably, MDPCs were able to readily generate myotubes in culture up until passage 8. Moreover, a decrease in myogenic capacity during serial passaging was concomitant with a gradual increase in the expression of the pre-adipocyte markers, CD105 and PDGFRA, and an increase in the ability of MDPCs to differentiate into adipocytes. In conclusion, explant culture provided a simple and efficient method to harvest enriched myogenic progenitors from pig skeletal muscle which could be maintained long-term and differentiated in vitro, thus providing a suitable system for studies on porcine muscle biology and applications in the expanding field of cultured meat.

The Role of Ubiquitin-Proteasome System in the Biology of Stem Cells

Selective degradation of cellular proteins by the ubiquitin-proteasome system (UPS) is one of the key regulatory mechanisms in eukaryotic cells. A growing body of evidence indicates that UPS is involved in the regulation of fundamental processes in mammalian stem cells, including proliferation, differentiation, cell migration, aging, and programmed cell death, via proteolytic degradation of key transcription factors and cell signaling proteins and post-translational modification of target proteins with ubiquitin. Studying molecular mechanisms of proteostasis in stem cells is of great importance for the development of new therapeutic approaches aimed at the treatment of autoimmune and neurodegenerative diseases, cancer, and other socially significant pathologies. This review discusses current data on the UPS functions in stem cells.

Revolutionizing orofacial pain management: the promising potential of stem cell therapy

Orofacial pain remains a significant health issue in the United States. Pain originating from the orofacial region can be composed of a complex array of unique target tissue that contributes to the varying success of pain management. Long-term use of analgesic drugs includes adverse effects such as physical dependence, gastrointestinal bleeding, and incomplete efficacy. The use of mesenchymal stem cells for their pain relieving properties has garnered increased attention. In addition to the preclinical and clinical results showing stem cell analgesia in non-orofacial pain, studies have also shown promising results for orofacial pain treatment. Here we discuss the outcomes of mesenchymal stem cell treatment for pain and compare the properties of stem cells from different tissues of origin. We also discuss the mechanism underlying these analgesic/anti-nociceptive properties, including the role of immune cells and the endogenous opioid system. Lastly, advancements in the methods and procedures to treat patients experiencing orofacial pain with mesenchymal stem cells are also discussed.

Comparative Analysis of Porcine Adipose- and Wharton's Jelly-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are promising candidates for tissue regeneration, cell therapy, and cultured meat research owing to their ability to differentiate into various lineages including adipocytes, chondrocytes, and osteocytes. As MSCs display different characteristics depending on the tissue of origin, the appropriate cells need to be selected according to the purpose of the research. However, little is known of the unique properties of MSCs in pigs. In this study, we compared two types of porcine mesenchymal stem cells (MSCs) isolated from the dorsal subcutaneous adipose tissue (adipose-derived stem cells (ADSCs)) and Wharton's jelly of the umbilical cord (Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs)) of 1-day-old piglets. The ADSCs displayed a higher proliferation rate and more efficient differentiation potential into adipogenic and chondrogenic lineages than that of WJ-MSCs; conversely, WJ-MSCs showed superior differentiation capacity towards osteogenic lineages. In early passages, ADSCs displayed higher proliferation rates and mitochondrial energy metabolism (measured based on the oxygen consumption rate) compared with that of WJ-MSCs, although these distinctions diminished in late passages. This study broadens our understanding of porcine MSCs and provides insights into their potential applications in animal clinics and cultured meat science.

Decreased CRISPLD2 expression impairs osteogenic differentiation of human mesenchymal stem cells during in vitro expansion

Human mesenchymal stem cells (hMSCs) are the cornerstone of regenerative medicine; large quantities of hMSCs are required via in vitro expansion to meet therapeutic purposes. However, hMSCs quickly lose their osteogenic differentiation potential during in vitro expansion, which is a major roadblock to their clinical applications. In this study, we found that the osteogenic differentiation potential of human bone marrow stem cells (hBMSCs), dental pulp stem cells (hDPSCs), and adipose stem cells (hASCs) was severely impaired after in vitro expansion. To clarify the molecular mechanism underlying this in vitro expansion-related loss of osteogenic capacity in hMSCs, the transcriptome changes following in vitro expansion of these hMSCs were compared. Cysteine-rich secretory protein LCCL domain-containing 2 (CRISPLD2) was identified as the most downregulated gene shared by late passage hBMSCs, hDPSCs, and hASCs. Both the secreted and non-secreted CRISPLD2 proteins progressively declined in hMSCs during in vitro expansion when the cells gradually lost their osteogenic potential. We thus hypothesized that the expression of CRISPLD2 is critical for hMSCs to maintain their osteogenic differentiation potential during in vitro expansion. Our studies showed that the knockdown of CRISPLD2 in early passage hBMSCs inhibited the cells' osteogenic differentiation in a siRNA dose-dependent manner. Transcriptome analysis and immunoblotting indicated that the CRISPLD2 knockdown-induced osteogenesis suppression might be attributed to the downregulation of matrix metallopeptidase 1 (MMP1) and forkhead box Q1 (FOXQ1). Furthermore, adeno-associated virus (AAV)-mediated CRISPLD2 overexpression could somewhat rescue the impaired osteogenic differentiation of hBMSCs during in vitro expansion. These results revealed that the downregulation of CRISPLD2 contributes to the impaired osteogenic differentiation of hMSCs during in vitro expansion. Our findings shed light on understanding the loss of osteogenic differentiation in hMSCs and provide a potential therapeutic target gene for bone-related diseases.

Ginsenoside Rg2 Promotes the Proliferation and Stemness Maintenance of Porcine Mesenchymal Stem Cells through Autophagy Induction

Mesenchymal stem cells (MSCs) can be used as a cell source for cultivated meat production due to their adipose differentiation potential, but MSCs lose their stemness and undergo replicative senescence during expansion in vitro. Autophagy is an important mechanism for senescent cells to remove toxic substances. However, the role of autophagy in the replicative senescence of MSCs is controversial. Here, we evaluated the changes in autophagy in porcine MSCs (pMSCs) during long-term culture in vitro and identified a natural phytochemical, ginsenoside Rg2, that could stimulate pMSC proliferation. First, some typical senescence characteristics were observed in aged pMSCs, including decreased EdU-positive cells, increased senescence-associated beta-galactosidase activity, declined stemness-associated marker OCT4 expression, and enhanced P53 expression. Importantly, autophagic flux was impaired in aged pMSCs, suggesting deficient substrate clearance in aged pMSCs. Rg2 was found to promote the proliferation of pMSCs using MTT assay and EdU staining. In addition, Rg2 inhibited D-galactose-induced senescence and oxidative stress in pMSCs. Rg2 increased autophagic activity via the AMPK signaling pathway. Furthermore, long-term culture with Rg2 promoted the proliferation, inhibited the replicative senescence, and maintained the stemness of pMSCs. These results provide a potential strategy for porcine MSC expansion in vitro.

Characterization of porcine mesenchymal stromal cells and their proliferative and osteogenic potential in long-term culture

Background: Porcine mesenchymal stromal cells (pMSCs) are considered a valuable research model for bone tissue engineering, which requires adequate amounts of viable cells with sufficient potential for osteogenic differentiation. For isolation and expansion of these cells through long-term culture, appropriate culture conditions are needed. Objective: To study the effect of extended in vitro cultivation on pMSC proliferation and differentiation potential using different osteogenic and adipogenic induction media. Methods: pMSCs were isolated from the bone marrow of adult Göttingen minipigs, cultured, expanded to passage 20 (~160 days) and characterized by their expression of cell surface markers (wCD44, CD45, CD90, SWC9, fibronectin), alkaline phosphatase (ALP), and osteocalcin and their potential for osteogenic and adipogenic differentiation using different induction media. Results: pMSCs retained their capacity for proliferation and osteogenic differentiation, and the number of CD90-positive cells increased significantly over more than 60 population doublings. CD90 expression in uninduced cells correlated strongly with ALP expression following osteogenic induction. Medium enriched with calcium yielded a stronger osteogenic response. Conclusion: The selection of CD90-positive MSCs and adequate levels of calcium seem to enhance the osteogenic phenotype for bone tissue engineering.

The Bumpy Road to Stem Cell Therapies: Rational Design of Surface Topographies to Dictate Stem Cell Mechanotransduction and Fate

Cells sense and respond to a variety of physical cues from their surrounding microenvironment, and these are interpreted through mechanotransductive processes to inform their behavior. These mechanisms have particular relevance to stem cells, where control of stem cell proliferation, potency, and differentiation is key to their successful application in regenerative medicine. It is increasingly recognized that surface micro- and nanotopographies influence stem cell behavior and may represent a powerful tool with which to direct the morphology and fate of stem cells. Current progress toward this goal has been driven by combined advances in fabrication technologies and cell biology. Here, the capacity to generate precisely defined micro- and nanoscale topographies has facilitated the studies that provide knowledge of the mechanotransducive processes that govern the cellular response as well as knowledge of the specific features that can drive cells toward a defined differentiation outcome. However, the path forward is not fully defined, and the "bumpy road" that lays ahead must be crossed before the full potential of these approaches can be fully exploited. This review focuses on the challenges and opportunities in applying micro- and nanotopographies to dictate stem cell fate for regenerative medicine. Here, key techniques used to produce topographic features are reviewed, such as photolithography, block copolymer lithography, electron beam lithography, nanoimprint lithography, soft lithography, scanning probe lithography, colloidal lithography, electrospinning, and surface roughening, alongside their advantages and disadvantages. The biological impacts of surface topographies are then discussed, including the current understanding of the mechanotransductive mechanisms by which these cues are interpreted by the cells, as well as the specific effects of surface topographies on cell differentiation and fate. Finally, considerations in translating these technologies and their future prospects are evaluated.

MSC therapy in livestock models

Mesenchymal stem cells (MSCs) have great value as therapeutic tools in a wide array of applications in regenerative medicine. The wide repertoire of cell functions regarding tissue regeneration, immunomodulation, and antimicrobial activity makes MSC-based therapy a strong candidate for treatment options in a variety of clinical conditions and should be studied to expand the current breadth of knowledge surrounding their physiological properties and therapeutic benefits. Livestock models are an appropriate resource for testing the efficacy of MSC therapies for their use in biomedical research and can be used to improve both human health and animal agriculture. Agricultural animal models such as pigs, cattle, sheep, and goats have grown in popularity for in vivo research relative to small animal models due to their overlapping similarities in structure and function that more closely mimic the human body. Cutaneous wound healing, bone regeneration, osteoarthritis, ischemic reperfusion injury, and mastitis recovery represent a few examples of the types of disease states that may be investigated in livestock using MSC-based therapy. Although the cost of agricultural animals is greater than small animal models, the information gained using livestock as a model holds great value for human applications, and in some cases, outcompetes the weight of information gained from rodent models. With emerging fields such as exosome-based therapy, proper in vivo models will be needed for testing efficacy and translational practice, i.e., livestock models should be strongly considered as candidates. The potential for capitalizing on areas that have crossover benefits for both agricultural economic gain and improved health of the animals while minimizing the gap between translational research and clinical practice are what make livestock great choices for experimental MSC models.

Perspectives on scaling production of adipose tissue for food applications

With rising global demand for food proteins and significant environmental impact associated with conventional animal agriculture, it is important to develop sustainable alternatives to supplement existing meat production. Since fat is an important contributor to meat flavor, recapitulating this component in meat alternatives such as plant based and cell cultured meats is important. Here, we discuss the topic of cell cultured or tissue engineered fat, growing adipocytes in vitro that could imbue meat alternatives with the complex flavor and aromas of animal meat. We outline potential paths for the large scale production of in vitro cultured fat, including adipogenic precursors during cell proliferation, methods to adipogenically differentiate cells at scale, as well as strategies for converting differentiated adipocytes into 3D cultured fat tissues. We showcase the maturation of knowledge and technology behind cell sourcing and scaled proliferation, while also highlighting that adipogenic differentiation and 3D adipose tissue formation at scale need further research. We also provide some potential solutions for achieving adipose cell differentiation and tissue formation at scale based on contemporary research and the state of the field.

Bovine Fetal Mesenchymal Stem Cells Obtained From Omental Adipose Tissue and Placenta Are More Resistant to Cryoprotectant Exposure Than Those From Bone Marrow

Recent studies have shown promise for the development of cellular therapies with mesenchymal stem cells (MSCs) in livestock species, specifically bovines, and cryopreservation is highly relevant for the advancement of these applications. The use of permeable and/or non-permeable cryoprotectant solutions is necessary to reduce cell damage during freezing and thawing, but these same compounds can also cause negative effects on MSCs and their therapeutic properties. Another important factor to consider is the tissue source of MSCs, since it is now known that MSCs from different tissues of the same individual do not behave the same way, so optimizing the type and concentration of cryoprotectants for each cell type is essential to achieve a large and healthy population of MSCs after cryopreservation. Furthermore, sources of MSCs that could provide great quantities, non-invasively and without ethical concerns, such as placental tissue, have great potential for the development of regenerative medicine in livestock species, and have not been thoroughly evaluated. The objective of this study was to compare the viability of bovine fetal MSCs extracted from bone marrow (BM), adipose tissue (AT), and placenta (PT), following their exposure (15 and 30 min) to several solutions of permeable (dimethyl sulfoxide and ethylene glycol) and non-permeable (trehalose) cryoprotectants. Viability assays were performed with Trypan Blue to assess post-exposure plasma membrane integrity. The apoptotic potential was estimated analyzing the mRNA abundance of BAX and BCL-2 genes using quantitative rt-PCR. Based on the results of the study, BM-MSC exhibited significantly lower viability compared to AT-MSC and PT-MSC, at both 15 and 30 min of exposure to cryoprotectant solutions. Nevertheless, viability did not differ among treatments for any of the cell types or timepoints studied. BCL-2 expression was higher in BM-MSC compared to AT-MSC, however, BAX/BCL-2 ratio did not differ. In conclusion, AT-MSC and PT-MSC were more resistant that BM-MSC, which showed higher sensitivity to experimental conditions, regardless of the exposure times, and cryoprotectant solutions used in the study.

Umbilical mesenchymal stem cell-derived extracellular vesicles as enzyme delivery vehicle to treat Morquio A fibroblasts

BACKGROUND

Mucopolysaccharidosis IVA (Morquio A syndrome) is a lysosomal storage disease caused by the deficiency of enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which results in the accumulation of the glycosaminoglycans (GAGs), keratan sulfate, and chondroitin-6-sulfate in the lysosomes of all tissues causing systemic dysfunction. Current treatments include enzyme replacement therapy (ERT) which can treat only certain aspects of the disease such as endurance-related biological endpoints. A key challenge in ERT is ineffective enzyme uptake in avascular tissues, which makes the treatment of the corneal, cartilage, and heart valvular tissue difficult. The aim of this study was to culture human umbilical mesenchymal stem cells (UMSC), demonstrate presence of GALNS enzyme activity within the extracellular vesicles (EVs) derived from these UMSC, and study how these secreted EVs are taken up by GALNS-deficient cells and used by the deficient cell's lysosomes.

METHODS

We obtained and cultured UMSC from the umbilical cord tissue from anonymous donors from the Saint Louis Cord Blood Bank. We characterized UMSC cell surface markers to confirm phenotype by cell sorting analyses. In addition, we confirmed that UMSC secrete GALNS enzyme creating conditioned media for co-culture experiments with GALNS deficient cells. Lastly, we isolated EVs derived from UMSC by ultracentrifugation to confirm source of GALNS enzyme.

RESULTS

Co-culture and confocal microscopy experiments indicated that the lysosomal content from UMSC migrated to deficient cells as evidenced by the peak signal intensity occurring at 15 min. EVs released by UMSC were characterized indicating that the EVs contained the active GALNS enzyme. Uptake of GALNS within EVs by deficient fibroblasts was not affected by mannose-6-phosphate (M6P) inhibition, suggesting that EV uptake by these fibroblasts is gradual and might be mediated by a different means than the M6P receptor.

CONCLUSIONS

UMSC can deliver EVs containing functional GALNS enzyme to deficient cells. This enzyme delivery method, which was unaffected by M6P inhibition, can function as a novel technique for reducing GAG accumulation in cells in avascular tissues, thereby providing a potential treatment option for Morquio A syndrome.

Proteomic analysis of hypoxia and non-hypoxia secretome mesenchymal stem-like cells from human breastmilk

Introduction

Breastmilk contains proteins and cells which have stem cell properties. The human breastmilk stem cell mimick mesenchymal stem cells and expresses pluripotency genes. The protein level of breastmilk is high in colostrum and gradually subsides in the first year of lactation. The mesenchymal stem cells from breastmilk can be an alternative source of stem cells that can potentially affect cardiovascular therapy. This study aimed to identify the proteomic analysis of secretome mesenchymal stem-like cells under hypoxia compared to non-hypoxia from human breastmilk stem cells.

Material and methods

The human breastmilk was collected from six healthy breastfeeding women and transported to the laboratory under aseptic conditions. The breastmilk cells were isolated then cultured. After 72 h, the human breastmilk stem cells reached confluence then cleaned up and isolated in serum-free media (spheroid) to allow serial passaging every 48 h. The acquisition stem cell was made with flow cytometry. The cells were divided into hBSC secretomes under hypoxia (A) and non-hypoxia (B) and analyzed for LC-MS to identify the peptide structure.

Results

The human breastmilk cells contained several mesenchymal stem-like cells in density 2.4 × 10⁶ cell/mL for hypoxia and 2 × 10⁶ cell/mL for non-hypoxia conditions. The human breastmilk stem cell surface markers derived from the third cell passage process were 93.77% for CD44, 98.69% for CD73, 88.45% for CD90, and 96.30% for CD105. The protein level of secretome mesenchymal stem -like cells under hypoxia was measured at 5.56 μg/mL and 4.28 μg/mL for non-hypoxia. The liquid chromatography-mass spectrometry analysis identified 130 and 59 peptides from hypoxia and non-hypoxia of the human breastmilk stem cell secretome sequentially. Some important proteomics structures were found in the hypoxic human breastmilk stem cell secretome, such as transforming growth factor-β, VE-cadherin, and caspase.

Conclusion

The human breastmilk cells contain mesenchymal stem-like cells and a high concentration of CD44, CD73, CD90, and CD105 as surface markers at third passage culture. The hypoxic hBSC secretome produces a higher protein level compare to non-hypoxia. The transforming growth factor -β was found in the hypoxic hBSC secretome as a modulator of VEGF-mediated angiogenesis.

Hydrostatic Pressure Regulates the Volume, Aggregation and Chondrogenic Differentiation of Bone Marrow Derived Stromal Cells

The limited ability of articular cartilage to self-repair has motivated the development of tissue engineering strategies that aim to harness the regenerative potential of mesenchymal stem/marrow stromal cells (MSCs). Understanding how environmental factors regulate the phenotype of MSCs will be central to unlocking their regenerative potential. The biophysical environment is known to regulate the phenotype of stem cells, with factors such as substrate stiffness and externally applied mechanical loads known to regulate chondrogenesis of MSCs. In particular, hydrostatic pressure (HP) has been shown to play a key role in the development and maintenance of articular cartilage. Using a collagen-alginate interpenetrating network (IPN) hydrogel as a model system to tune matrix stiffness, this study sought to investigate how HP and substrate stiffness interact to regulate chondrogenesis of MSCs. If applied during early chondrogenesis in soft IPN hydrogels, HP was found to downregulate the expression of ACAN, COL2, CDH2 and COLX, but to increase the expression of the osteogenic factors RUNX2 and COL1. This correlated with a reduction in SMAD 2/3, HDAC4 nuclear localization and the expression of NCAD. It was also associated with a reduction in cell volume, an increase in the average distance between MSCs in the hydrogels and a decrease in their tendency to form aggregates. In contrast, the delayed application of HP to MSCs grown in soft hydrogels was associated with increased cellular volume and aggregation and the maintenance of a chondrogenic phenotype. Together these findings demonstrate how tailoring the stiffness and the timing of HP exposure can be leveraged to regulate chondrogenesis of MSCs and opens alternative avenues for developmentally inspired strategies for cartilage tissue regeneration.

Improving Culture Conditions, Proliferation, and Migration of Porcine Mesenchymal Stem Cells on Spinal Cord Contusion Injury Model in vitro

Adipose tissue-derived mesenchymal stem cells (AD-MSCs) are promising for cell therapy in spinal cord injury (SCI). The pig is one of the most approximate models of many human diseases, including SCI. In our study, we selected the optimal conditions for the culture of porcine AD-MSCs and developed an in vitro SCI model based on the culture of cells in injured spinal cord extracts (SCE) 3 days and 6 weeks after SCI. We show that Dulbecco's Modified Eagle Medium (DMEM) with 20% serum content, supplemented with a combination of 5 mM L-ascorbate-2-phosphate and nonessential amino acids, stimulated a typical fibroblast-like morphology and high proliferation of porcine AD-MSCs. SCE caused a higher proliferation of porcine AD-MSCs compared with extracts from an intact spinal cord. The optimal proliferating effect was achieved using rostral 3 days SCE, and proliferation was lower in caudal and central SCE. Porcine AD-MSCs migration to the 3 days and 6 weeks SCE was higher than to an intact one and preferred the rostral SCE, avoiding central and caudal SCE. We also studied 13 cytokines contained in SCE but did not observe any definite relationship between some analyte concentrations and a change in the behavior of AD-MSCs.

Osteogenic differentiation potential of porcine bone marrow mesenchymal stem cell subpopulations selected in different basal media

Multipotent porcine mesenchymal stem cells (pMSC) are invaluable for research and therapeutic use in regenerative medicine. Media used for derivation and expansion of pMSC may play an important role for the selection of MSC subpopulation at an early stage and thereby, the specific basal medium may also affect differentiation potential of these cells. The present study was undertaken to evaluate the effects of αMEM, aDMEM, M199, αMEM/M199, aDMEM/M199 and αMEM/aDMEM media on (1) porcine bone marrow MSC derivation; (2) expression of number of osteogenic markers (ALP, COL1A1, SPP1 and BGLAP) at 5th and 10th passage in pMSC before differentiation; and (3) differentiation of pMSC (at 5th passage) to osteogenic lineage. Morphological changes and matrix formation in osteogenic cells were evaluated by microscopic examination. Calcium deposits in osteocytes were confirmed by Alizarin Red S staining. Based on expression of different markers, it was evident that selection of bone marrow pMSC subpopulations was independent of basal media used. However, the differentiation of those pMSCs, specifically to osteogenic lineage, was dependent on the medium used for expansion of pMSC at the pre-differentiation stage. We demonstrated here that the pMSC grown in combined αMEM/aDMEM (1:1) medium expressed number of osteogenic markers and these pMSC underwent osteogenic differentiation most efficiently, in comparison to porcine mesenchymal stem cells grown in other media. In conclusion, osteogenic differentiation potential of pMSC maintained in αMEM/aDMEM medium was observed significantly higher compared to cells cultivated in other media and therefore, the combined medium αMEM/aDMEM (1:1) may preferentially be used for expansion of pMSC, if needed for osteogenic differentiation.

Secretome studies of mesenchymal stromal cells (MSCs) isolated from three tissue sources reveal subtle differences in potency

Human mesenchymal stromal cells (MSCs) are currently the leading candidate for cell-based therapeutics. While the use of MSCs in transplantation therapies is widely expanding, still, there is a lot of scope for better understanding of the mechanisms underlying their effects. We have generated MSCs from pre- and post-natal human tissue sources such as Wharton's jelly (WJ), stem cells from human exfoliated deciduous teeth (SHED), and bone marrow (BM). We then expanded, banked, and characterized them based on morphology, growth kinetics, senescence, immunophenotype, gene expression, and secretion of growth factors. Although the immunophenotype was very similar across MSCs from the three types of donor tissues, they showed minor variations in their growth kinetics. Further, a higher percentage of senescent cells were observed in BM-MSCs than in WJ-MSCs and SHED. Gene expression analysis showed the increased expression of INF-γ, PDGFA, VEGF, IL10, and SDF in SHED over WJ-MSC and BM-MSC. Comparative secretome profiling by ELISA demonstrated the presence of FGF-2, IL-10, PDGF, SDF-1, Ang-1, TGF-β3, HGF, INF-γ, VEGF, and IL-6 in cell culture supernatants. Based on our findings, WJ-MSC and SHED appear more potent than BM-MSC for managing inflammation, immunomodulation, angiogenesis, fibrosis, and scarring. Due to widespread application of MSCs in cell replacement therapy, these subtle differences need to be taken into consideration while designing stem cell-based clinical trials.

Isolation, culture, and induced multiple differentiation of Mongolian sheep adipose-derived mesenchymal stem cells

Adipose-derived mesenchymal stem cells (ADSC) are adult pluripotent cells and important resources for cell-based therapies of animals. There are presently different kinds of somatic cells used as donor cells for clone successfully. However, studies on somatic cell nuclear transplantation (SCNT) using ADSC as donor cells from Mongolian sheep have not been reported up to now. This study tested optimal methods of isolating, purifying, and proliferating Mongolian sheep ADSC, and determine their multiple differentiation potentiality. Adipose tissue was removed from approximately 2-year-old sheep and ADSC were harvested by pancreatic enzyme decomposition and adherent culture method. The growth curves of the Passages 1, 5, and 10 cultures were plotted and the exponential growth was determined as a population doubling time of 34.1 h. The expression of OCT4, SOX2, and NANOG genes were increased at Passage 3 (P3) as seen by reverse transcription polymerase chain reaction (RT-PCR) analysis. ADSC from Passage 3 were induced to undergo neurogenesis and form cardiomyocytes and pancreatic islet-like cells under inductive environments in vitro. The differentiation properties of cardiomyocytes and islet-like cells were confirmed by histological staining with toluidine blue, periodic acid-Schiff, and dithizone. The expression of specific genes in these cells were also detected by RT-PCR. Our study results confirm that isolated cells were indeed ADSC and may provide valuable materials for somatic cell clone and transgenic research.

The protective effects of HMGA2 in the senescence process of bone marrow-derived mesenchymal stromal cells

Bone marrow-derived mesenchymal stromal cells (MSCs) have been wildly applied to cell-based strategies for tissue engineering and regenerative medicine; however, they have to undergo the senescence process and thus appeared to be less therapeutic effective. HMGA2, a protein belonged to high mobility group A (HMGA) family, exhibits an inverse expression level related to embryonic development and acts as a developmental regulator in stem cell self-renewal progression. Therefore, we performed senescence-associated β-galactosidase (SA-β-gal) staining, transwell assay, to examine the changes of MSCs in different stages and then over-expressed HMGA2 in MSCs by lentivirus transfection. We found the percentage of SA-β-gal staining positive cells in MSCs from 24-month-old Sprague-Dawley (SD) rats (O-MSCs) was significantly higher compared with MSCs from 2-week-old SD rats (Y-MSCs), and the expression levels of P21 and P53, two senescence-related molecules, were also significantly up-regulated in O-MSCs than in Y-MSCs. In contrast, the HMGA2 expression level in O-MSCs was dramatically down-regulated in contrast to Y-MSCs. In additional, the migration ability in O-MSCs was significantly attenuated than in Y-MSCs. After successfully over-expressed HMGA2 in O-MSCs, the percentage of SA-β-gal staining positive cells and the expression levels of P21 and P53 were reduced, and the migration ability was improved compared with O-MSCs without treatment. Further, mRNA sequencing analysis revealed that overexpression of HMGA2 changed the expression of genes related to cell proliferation and senescence, such as Lyz2, Pf4, Rgs2, and Mstn. Knockdown of Rgs2 in HMGA2 overexpression O-MSCs could antagonize the protective effect of HMGA2 in the senescence process of O-MSCs.

Label-free separation of mesenchymal stem cell subpopulations with distinct differentiation potencies and paracrine effects

Mesenchymal stem cells (MSCs) have the capability to differentiate into multiple cell lineages, and produce trophic factors to facilitate tissue repair and regeneration, and disease regression. However, the heterogeneity of MSCs, whether inherent or developed during culture expansion, has a significant impact on their therapeutic efficacy. Therefore, the ability to identify and select an efficacious subpopulation of MSCs targeting specific tissue damage or disease holds great clinical significance. In this study, we separated three subpopulations from culture expanded human bone marrow derived MSCs according to cell size, using a high-throughput label-free microfluidic cell sorting technology. The size-sorted MSC subpopulations varied in tri-lineage differentiation potencies. The large MSCs showed the strongest osteogenesis, medium-size MSCs were advantageous in chondrogenesis and adipogenesis, and the small MSCs showed the weakest tri-lineage differentiation. The size-sorted MSC subpopulations also exhibited different secretome profiles. The large MSC secretome possessed highest levels of osteogenic promotor proteins and senescence-associated factors, but lower levels of osteogenic inhibitor proteins compared to the medium-size MSC secretome. The medium-size MSC secretome had high levels of chondrogenic promotor proteins, and contained lower levels of chondrogenic inhibitor proteins compared to the large MSC secretome. The secretome of size-sorted MSC subpopulations showed differences in paracrine effects. We found that the secretome of large MSCs enhanced osteogenic and adipogenic potencies during MSC culture expansion, but also induced cell senescence; and the secretome of medium-size MSCs promoted chondrogenesis. This study demonstrates size-dependent differentiation potency and secretome profile of MSC subpopulations, and provides an effective and practical technology to isolate the respective subpopulations, which may be used for more targeted tissue repair and regeneration.

Model for Studying the Effects of Chronic Metabolic Disease on Endogenous Bone Marrow Stem Cell Populations

Disease-associated impairment/dysfunction of stem cell populations is prominent in chronic metabolic and inflammatory diseases, such as type 2 diabetes mellitus (DM) where the multifunctional properties (viability, proliferation, paracrine secretion, multilineage differentiation) of bone marrow resident mesenchymal stem cells (MSCs) can be affected. The growth and viability impairments make it difficult to study the underlying molecular mechanisms related to the dysfunction of these cells in vitro. We have consequently optimized the isolation and culture conditions for impaired/dysfunctional bone marrow MSCs from B6.Cg-Lep^ob/J obese prediabetic mice. The method described here permits ex vivo investigations into disease-associated functional impairments and the dysregulated molecular mechanisms in these primary MSCs through direct comparisons with their healthy wild-type C57BL6/J control mouse counterparts.

The Importance of Stem Cell Senescence in Regenerative Medicine

Mesenchymal stem cells (MSCs) are an interesting tool in regenerative medicine and a unique cell-based therapy to treat aging-associated diseases. Successful MSC therapy needs a large-scale cell culture, and requires a prolonged in vitro cell culture that subsequently leads to cell senescence. Administration of senescent MSCs results in inefficient cell differentiation in the clinical setting. Therefore, it is of utmost importance to enhance our knowledge about the aging process and methods to detect cell senescence in order to overcome this challenge. Numerous studies have addressed senescence in various aspects. Here, we review the characteristics of MSCs, how aging affects their features, mechanisms involved in aging of MSCs, and potential approaches to detect MSC senescence in vitro.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.

Doxorubicin-induced senescence through NF-κB affected by the age of mouse mesenchymal stem cells

The senescence is proposed as a defense mechanism against many anticancer drugs. This complication is marked by differences in cell appearance and inner structures underlying the impairment in function. In this experiment, doxorubicin-induced senescence was assessed in mesenchymal stem cells (MSCs) isolated from the bone marrow of different-aged Balb/c mice (1, 8, and 16 months old). In addition, doxorubicin kinetics in culture medium were investigated to compare the drug absorption rate by different-aged MSCs. Several methods were exerted including Sandwich ELISA for NF-κB activation, propidium iodide staining for cell cycle analysis, Flow-fluorescent in-situ hybridization (Flow-FISH) assay for telomere length measurement, and specific staining for evaluation of β-galactosidase. Determination of doxorubicin in a medium was performed by high-performance liquid chromatography technique. Following doxorubicin exposure, cells underwent substantial telomere shortening, cell cycle arresting in G2 phase, and increased β-galactosidase activity. Interestingly, the enhanced level of NF-κB was observed in all age groups. The highest and lowest sensitivity to telomere shortening attributed to 1- and 8-month-old MSCs, respectively. In consistent with Flow-FISH results, the β-galactosidase activity was higher in young-aged MSCs after treatment. Statistical analysis indicated a correlation between the reduction of telomere length and cessation in G2 phase. Regarding the obtained kinetics equations, the rate of doxorubicin absorption by all aged MSCs followed the same trend. In conclusion, the changing of some elements involved in doxorubicin-induced senescence can be affected by the age of the cells significantly in young MSCs than two other age groups. Hereupon, these changing patterns can open new insights to develop anticancer therapeutic strategies.

Determinants of stem cell lineage differentiation toward chondrogenesis versus adipogenesis

Adult stem cells, also termed as somatic stem cells, are undifferentiated cells, detected among differentiated cells in a tissue or an organ. Adult stem cells can differentiate toward lineage specific cell types of the tissue or organ in which they reside. They also have the ability to differentiate into mature cells of mesenchymal tissues, such as cartilage, fat and bone. Despite the fact that the balance has been comprehensively scrutinized between adipogenesis and osteogenesis and between chondrogenesis and osteogenesis, few reviews discuss the relationship between chondrogenesis and adipogenesis. In this review, the developmental and transcriptional crosstalk of chondrogenic and adipogenic lineages are briefly explored, followed by elucidation of signaling pathways and external factors guiding lineage determination between chondrogenic and adipogenic differentiation. An in-depth understanding of overlap and discrepancy between these two mesenchymal tissues in lineage differentiation would benefit regeneration of high-quality cartilage tissues and adipose tissues for clinical applications.

Decellularized biological scaffold and stem cells from autologous human adipose tissue for cartilage tissue engineering

Here, the in vitro engineering of a cartilage-like tissue by using decellularized extracellular matrix scaffold (hECM) seeded with human adipose stem cells (hASCs) which can both be isolated from the human waste adipose tissue is described. Cell-free, highly fibrous and porous hECM was produced using a protocol containing physical (homogenization, centrifugation, molding) and chemical (crosslinking) treatments, characterized by SEM, histochemistry, immunohistochemistry and in vitro cell interaction study. A construct of hECM seeded with hASCs was cultured in chondrogenic medium (with TGF-β3 and BMP-6) for 42 days. SEM and histology showed that the biological scaffold was highly porous and had a compact structure suitable for handling and subsequent cell culture stages. Cells successfully integrated into the scaffold and had good cellular viability and continuity to proliferate. Constructs showed the formation of cartilage-like tissue with the synthesis of cartilage-specific proteins, Collagen type II and Aggrecan. Dimethylmethylene blue dye binding assay demonstrated that the GAG content of the constructs was in tendency to increase with time confirming chondrogenic differentiation of hASCs. The results support that human waste adipose tissue is an important source for decellularized hECM as well as stem cells, and adipose hECM scaffold provides a suitable environment for chondrogenic differentiation of hASCs.

Nomenclature Inconsistency and Selective Outcome Reporting Hinder Understanding of Stem Cell Therapy for the Knee

BACKGROUND

The prospect of treating knee cartilage injury/pathology with mesenchymal stem cells (MSCs) has garnered considerable attention in recent years, but study heterogeneity and a lack of randomized controlled trials (RCTs) preclude quantitative analysis. The purpose of this review was to provide clinicians with an overview of RCTs that addresses 2 key areas that have been largely overlooked: nomenclature inconsistency and selective outcome reporting.

METHODS

RCTs that purported to use stem cells or MSCs to treat knee cartilage were identified with use of PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses). Study variables were compiled, and methodological quality was assessed. The cell treatments and the methods used to characterize them were recorded and compared. Clinical, radiographic, and arthroscopic outcomes were extracted and evaluated qualitatively.

RESULTS

There was extensive variation among the treatments, adjuvant therapies, and outcome measures. Treatments did not coincide with terminology. Significant differences in clinical outcomes were reported infrequently, and intra-group improvements or inter-group subscore differences were consistently highlighted, particularly when inter-group comparisons were left unreported.

CONCLUSIONS

Overall, there are isolated cases in which positive efficacy results have been published, but our results suggest that the generally positive efficacy conclusions concerning stem cell therapy for knee cartilage pathology may be overstated. Nevertheless, it is important to understand that the efficacy of stem cell therapies should not be considered in aggregate. Cells that are procured or processed differently produce entirely different drugs. When evaluating the efficacy of "stem cell" therapies, clinicians must consider the methodological quality, nomenclature, and inherent distinctness of each treatment.

MiR-1292 Targets FZD4 to Regulate Senescence and Osteogenic Differentiation of Stem Cells in TE/SJ/Mesenchymal Tissue System via the Wnt/β-catenin Pathway

With the expansion of the elderly population, age-related osteoporosis and the resulting bone loss have become a significant health and socioeconomic issue. In Triple Energizer (TE)/San Jiao (SJ)/mesenchymal tissue system, mesenchymal stem cell (MSC) senescence, and impaired osteogenesis are thought to contribute to age-related diseases such as osteoporosis. Therefore, comprehending the molecular mechanisms underlying MSC senescence and osteogenesis is essential to improve the treatment of bone metabolic diseases. With the increasing role of miRNAs in MSC aging and osteogenic differentiation, we need to understand further how miRNAs participate in relevant mechanisms. In this study, we observed that the expression of miR-1292 was augmented during cellular senescence and lessened with osteogenesis in human adipose-derived mesenchymal stem cells (hADSCs). miR-1292 expression was positively correlated with senescence markers and negatively associated with bone formation markers in clinical bone samples. Overexpression of miR-1292 notably accelerated hADSC senescence and restrained osteogenesis, whereas its knockdown decreased senescence and enhanced osteogenic differentiation. Furthermore, miR-1292 upregulation inhibited ectopic bone formation in vivo. Mechanistically, FZD4 was identified as a potential target of miR-1292. Downregulation of FZD4 phenocopied the effect of miR-1292 overexpression on hADSC senescence and osteogenic differentiation. Moreover, the impact of miR-1292 suppression on senescence and osteogenesis were reversed by the FZD4 knockdown. Pathway analysis revealed that miR-1292 regulates hADSC senescence and osteogenesis through the Wnt/β-catenin signaling pathway. Thus, TE/SJ/mesenchymal tissue system is the largest organ composed of various functional cells derived from mesoderm, responsible for maintaining homeostasis and regulating cell senescence. miR-1292 might serve as a novel therapeutic target for the prevention and treatment of osteoporosis or other diseases related to bone metabolism and aging.

Cardiosphere-Derived Cells and Ischemic Heart Failure

After a myocardial infarction, heart tissue becomes irreversibly damaged, leading to scar formation and inevitably ischemic heart failure. Of the many available interventions after a myocardial infarction, such as percutaneous intervention or pharmacological optimization, none can reverse the ischemic insult on the heart and restore cardiac function. Thus, the only available cure for patients with scarred myocardium is allogeneic heart transplantation, which comes with extensive costs, risks, and complications. However, multiple studies have shown that the heart is, in fact, not an end-stage organ and that there are endogenous mechanisms in place that have the potential to spark regeneration. Stem cell therapy has emerged as a potential tool to tap into and activate this endogenous framework. Particularly promising are stem cells derived from cardiac tissue itself, referred to as cardiosphere-derived cells (CDCs). CDCs can be extracted and isolated from the patient's myocardium and then administered by intramyocardial injection or intracoronary infusion. After early success in the animal model, multiple clinical trials have demonstrated the safety and efficacy of autologous CDC therapy in humans. Clinical trials with allogeneic CDCs showed early promising results and pose a potential "off-the-shelf" therapy for patients in the acute setting after a myocardial infarction. The mechanism responsible for CDC-induced cardiac regeneration seems to be a combination of triggering native cardiomyocyte proliferation and recruitment of endogenous progenitor cells, which most prominently occurs via paracrine effects. A further understanding of the mediators involved in paracrine signaling can help with the development of a stem cell-free therapy, with all the benefits and none of the associated complications.

Age-related Changes in Bone Marrow Mesenchymal Stromal Cells: A Potential Impact on Osteoporosis and Osteoarthritis Development

Aging at the cellular level is a complex process resulting from accumulation of various damages leading to functional impairment and a reduced quality of life at the level of the organism. With a rise in the elderly population, the worldwide incidence of osteoporosis (OP) and osteoarthritis (OA) has increased in the past few decades. A decline in the number and "fitness" of mesenchymal stromal cells (MSCs) in the bone marrow (BM) niche has been suggested as one of the factors contributing to bone abnormalities in OP and OA. It is well recognized that MSCs in vitro acquire culture-induced aging features such as gradual telomere shortening, increased numbers of senescent cells, and reduced resistance to oxidative stress as a result of serial population doublings. In contrast, there is only limited evidence that human BM-MSCs "age" similarly in vivo. This review compares the various aspects of in vitro and in vivo MSC aging and suggests how our current knowledge on rejuvenating cultured MSCs could be applied to develop future strategies to target altered bone formation processes in OP and OA.

Isolating Pediatric Mesenchymal Stem Cells with Enhanced Expansion and Differentiation Capabilities

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

Altered properties of feline adipose-derived mesenchymal stem cells during continuous in vitro cultivation

Cytotherapy with mesenchymal stem cells (MSCs) has been studied in many species, and often requires in vitro cell expansion to obtain therapeutic doses of stem cells. Because the characteristics of MSCs, such as self-renewal and multi-lineage differentiation, can be altered by long-term culture, it is important to maintain stemness during cultivation. This study assessed the changes in the characteristics of feline adipose tissue-derived (fAT)-MSCs during in vitro passaging. Stem cells isolated from the adipose tissue of donor cats were cultured for seven sub-passages. Proliferation capacity was analyzed by calculating the cell doubling time and by colorimetric assay. Expression of stem cell-specific markers was evaluated by quantitative reverse transcription (qRT)-PCR and immunophenotyping. Expression of adipogenic and osteogenic differentiation markers was also measured by qRT-PCR. Histochemical staining and measurement of β-galactosidase activity were conducted to detect cellular senescence. The cell proliferation rate decreased significantly at passage 5 (P5). Gene expression levels of pluripotency markers (Sox2, Nanog and Klf4) and stem cell surface markers (CD9, CD44, CD90 and CD105) decreased during continuous culture; in most assays, statistically significant changes were observed at P5. The ability of cells to undergo adipogenic or osteogenic differentiation was inversely proportional to the number of passages. The proportion of senescent cells increased with the number of passages. These results suggest that repeated passages alter the proliferation and multipotency of fAT-MSCs. In clinical trials, early-passage cells should be used to achieve the maximum therapeutic effect.

Effects of Passage Number and Differentiation Protocol on the Generation of Dopaminergic Neurons from Rat Bone Marrow-Derived Mesenchymal Stem Cells

Multiple studies have demonstrated the ability of mesenchymal stem cells (MSCs) to differentiate into dopamine-producing cells, in vitro and in vivo, indicating their potential to be used in the treatment of Parkinson’s disease (PD). However, there are discrepancies among studies regarding the optimal time (i.e., passage number) and method for dopaminergic induction, in vitro. In the current study, we compared the ability of early (P4) and later (P40) passaged bone marrow-derived MSCs to differentiate into dopaminergic neurons using two growth-factor-based approaches. A direct dopaminergic induction (DDI) was used to directly convert MSCs into dopaminergic neurons, and an indirect dopaminergic induction (IDI) was used to direct MSCs toward a neuronal lineage prior to terminal dopaminergic differentiation. Results indicate that both early and later passaged MSCs exhibited positive expression of neuronal and dopaminergic markers following either the DDI or IDI protocols. Additionally, both early and later passaged MSCs released dopamine and exhibited spontaneous neuronal activity following either the DDI or IDI. Still, P4 MSCs exhibited significantly higher spiking and bursting frequencies as compared to P40 MSCs. Findings from this study provide evidence that early passaged MSCs, which have undergone the DDI, are more efficient at generating dopaminergic-like cells in vitro, as compared to later passaged MSCs or MSCs that have undergone the IDI.

Evaluation of changes arising in the pig mesenchymal stromal cells transcriptome following cryopreservation and Trichostatin A treatment

Cryopreservation is an important procedure in maintenance and clinical applications of mesenchymal stem/stromal cells (MSCs). Although the methods of cell freezing using various cryoprotectants are well developed and allow preserving structurally intact living cells, the freezing process can be considered as a severe cellular stress associated with ice formation, osmotic damage, cryoprotectants migration/cytotoxicity or rapid cell shrinkage. The cellular response to freezing stress is aimed at the restoring of homeostasis and repair of cell damage and is crucial for cell viability. In this study we evaluated the changes arising in the pig mesenchymal stromal cell transcriptome following cryopreservation and showed the vast alterations in cell transcriptional activity (5,575 genes with altered expression) suggesting the engagement in post-thawing cell recovery of processes connected with cell membrane tension regulation, membrane damage repair, cell shape maintenance, mitochondria-connected energy homeostasis and apoptosis mediation. We also evaluated the effect of known gene expression stimulator—Trichostain A (TSA) on the frozen/thawed cells transcriptome and showed that TSA is able to counteract to a certain extent transcriptome alterations, however, its specificity and advantages for cell recovery after cryopreservation require further studies.

Therapeutic Benefit for Late, but Not Early, Passage Mesenchymal Stem Cells on Pain Behaviour in an Animal Model of Osteoarthritis

Background

Mesenchymal stem cells (MSCs) have a therapeutic potential for the treatment of osteoarthritic (OA) joint pathology and pain. The aims of this study were to determine the influence of a passage number on the effects of MSCs on pain behaviour and cartilage and bone features in a rodent model of OA.

Methods

Rats underwent either medial meniscal transection (MNX) or sham surgery under anaesthesia. Rats received intra-articular injection of either 1.5 × 10⁶ late passage MSCs labelled with 10 μg/ml SiMAG, 1.5 × 10⁶ late passage mesenchymal stem cells, the steroid Kenalog (200 μg/20 μL), 1.5 × 10⁶ early passage MSCs, or serum-free media (SFM). Sham-operated rats received intra-articular injection of SFM. Pain behaviour was quantified until day 42 postmodel induction. Magnetic resonance imaging (MRI) was used to localise the labelled cells within the knee joint.

Results

Late passage MSCs and Kenalog attenuated established pain behaviour in MNX rats, but did not alter MNX-induced joint pathology at the end of the study period. Early passage MSCs exacerbated MNX-induced pain behaviour for up to one week postinjection and did not alter joint pathology.

Conclusion

Our data demonstrate for the first time the role of a passage number in influencing the therapeutic effects of MSCs in a model of OA pain.

Downregulation of heat shock protein B8 decreases osteogenic differentiation potential of dental pulp stem cells during in vitro proliferation

OBJECTIVES

Tissue-derived stem cells, such as dental pulp stem cells (DPSCs), reduce differentiation capability during in vitro culture. We found that cultured DPSCs reduce expression of heat shock protein B8 (HspB8) and GIPC PDZ domain containing family member 2 (Gipc2). Our objectives were to evaluate the changes in DPSC composition during in vitro proliferation and to determine whether HspB8 and Gipc2 have function in differentiation potential of DPSCs.

MATERIALS AND METHODS

Different passages of rat DPSCs were evaluated for changes in CD90+ and/or CD271+ stem cells and changes in osteogenic potential. Real-time RT-PCR and immunostaining were conducted to determine expression of HspB8 and Gipc2. Expression of the genes in DPSCs was knocked down by siRNA, followed by osteogenic induction to evaluate the function of the genes.

RESULTS

About 90% of cells in the DPSC cultures were CD90+ and/or CD271+ cells without dramatic change during in vitro proliferation. The DPSCs at passages 3 to 5 (P3 to P5) possess strong osteogenic potential, but such potential was greatly reduced at later passages. Expression of HspB8 and Gipc2 was significantly reduced at P11 versus P3. Knock-down of HspB8 expression abolished osteogenic potential of the DPSCs, but knock-down of Gipc2 had no effect.

CONCLUSIONS

CD90+ and CD271+ cells are the major components of DPSCs in in vitro culture. High-level expression of HspB8 was critical for maintaining differentiation potential of DPSCs.

Osteogenic differentiation of 3D cultured mesenchymal stem cells induced by bioactive peptides

OBJECTIVES

Bioactive peptides derived from receptor binding motifs of native proteins are a potent source of bioactive molecules that can induce signalling pathways. These peptides could substitute for osteogenesis promoting supplements. The work presented here compares three kinds of bioactive peptides derived from collagen III, bone morphogenetic protein 7 (BMP-7) and BMP-2 with their potential osteogenic activity on the model of porcine mesenchymal stem cells (pMSCs).

MATERIALS AND METHODS

pMSCs were cultured on electrospun polycaprolactone nanofibrous scaffolds with different concentrations of the bioactive peptides without addition of any osteogenic supplement. Analysis of pMSCs cultures included measurement of the metabolic activity and proliferation, immunofluorescence staining and also qPCR.

RESULTS

Results showed no detrimental effect of the bioactive peptides to cultured pMSCs. Based on qPCR analysis, the bioactive peptides are specific for osteogenic differentiation with no detectable expression of collagen II. Our results further indicate that peptide derived from BMP-2 protein promoted the expression of mRNA for osteocalcin (OCN) and collagen I significantly compared to control groups and also supported deposition of OCN as observed by immunostaining method.

CONCLUSION

The data suggest that bioactive peptide with an amino acid sequence of KIPKASSVPTELSAISTLYL derived from BMP-2 protein was the most potent for triggering osteogenic differentiation of pMSCs.

Acetoacetate is a more efficient energy-yielding substrate for human mesenchymal stem cells than glucose and generates fewer reactive oxygen species

Stem cells have been assumed to demonstrate a reliance on anaerobic energy generation, suited to their hypoxic in vivo environment. However, we found that human mesenchymal stem cells (hMSCs) have an active oxidative metabolism with a range of substrates. More ATP was consistently produced from substrate oxidation than glycolysis by cultured hMSCs. Strong substrate preferences were shown with the ketone body, acetoacetate, being oxidised at up to 35 times the rate of glucose. ROS-generation was 45-fold lower during acetoacetate oxidation compared with glucose and substrate preference may be an adaptation to reduce oxidative stress. The UCP2 inhibitor, genipin, increased ROS production with either acetoacetate or glucose by 2-fold, indicating a role for UCP2 in suppressing ROS production. Addition of pyruvate stimulated acetoacetate oxidation and this combination increased ATP production 27-fold, compared with glucose alone, which has implications for growth medium composition. Oxygen tension during culture affected metabolism by hMSCs. Between passages 2 and 5, rates of both glycolysis and substrate-oxidation increased at least 2-fold for normoxic (20% O₂)- but not hypoxic (5% O₂)-cultured hMSCs, despite declining growth rates and no detectable signs of differentiation. Culture of the cells with 3-hydroxybutyrate abolished the increased rates of these pathways. These findings have implications for stem cell therapy, which necessarily involves in vitro culture of cells, since low passage number normoxic cultured stem cells show metabolic adaptations without detectable changes in stem-like status.

Impact of Cryopreservation on Caprine Fetal Adnexa Derived Stem Cells and Its Evaluation for Growth Kinetics, Phenotypic Characterization, and Wound Healing Potential in Xenogenic Rat Model

This study was conducted to know the impact of cryopreservation on caprine fetal adnexa derived mesenchymal stem cells (MSCs) on the basic stem cell characteristics. Gravid caprine uteri (2-3 months) were collected from local abattoir to derive (amniotic fluid [cAF], amniotic sac [cAS], Wharton's jelly [cWJ], and cord blood [cCB]) MSCs and expanded in vitro. Cells were cryopreserved at 3rd passage (P3) using 10% DMSO. Post-thaw viability and cellular properties were assessed. Cells were expanded to determine growth kinetics, tri-lineage differentiation, localization, and molecular expression of MSCs and pluripotency markers; thereafter, these cells were transplanted in the full-thickness (2 × 2cm² ) rat skin wound to determine their wound healing potential. The post-thaw (pt) growth kinetics study suggested that cWJ MSCs expanded more rapidly with faster population doubling time (PDT) than that of other fetal adnexa MSCs. The relative mRNA expression of surface antigens (CD73, CD90, and CD 105) and pluripotency markers (Oct4, KLF, and cMyc) was higher in cWJ MSCs in comparison to cAS, cAF, and cCB MSCs post-thaw. The percent wound contraction on 7th day was more than 50% for all the MSC-treated groups (pre and post-thaw), against 39.55% in the control group. On day 28th, 99% and more wound contraction was observed in cAF, cAF-pt, cAS-pt, cWJ, cWJ-pt, and cCB, MSCs with better scores for epithelization, neovascularization, and collagen characteristics at a non-significant level. It is concluded that these MSCs could be successfully cryopreserved without altering their stemness and wound healing properties. J. Cell. Physiol. 232: 2186-2200, 2017. © 2016 Wiley Periodicals, Inc.

Calcium Concentration in Culture Medium as a Nondestructive and Rapid Marker of Osteogenesis

Artificial bones made of β-tricalcium phosphate (β-TCP) combined with bone marrow-derived mesenchymal stromal cells (BM-MSCs) are used for effective reconstruction of bone defects caused by genetic defects, traumatic injury, or surgical resection of bone tumors. However, the selection of constructs with high osteogenic potential before implantation is challenging. The purpose of this study was to determine whether the calcium concentration in BM-MSC culture medium can be used as a nondestructive and simple osteogenic marker for selecting tissue-engineered grafts constructed using β-TCP and BM-MSCs. We prepared three cell passages of BM-MSCs derived from three 7-week-old, male Fischer 344 rats; the cells were cultured in osteoinductive medium in the presence of β-TCP for 15 days. The medium was replaced with fresh medium on day 1 in culture and subsequently changed every 48 h; it was collected for measurement of osteocalcin secretion and calcium concentration by enzyme-linked immunosorbent assay and X-ray fluorescence spectrometry, respectively. After cultivation, the constructs were implanted subcutaneously into the backs of recipient rats. Four weeks after implantation, the alkaline phosphatase (ALP) activity and osteocalcin content of the constructs were measured. A strong inverse correlation was observed between the calcium concentration in the medium and the ALP activity and osteocalcin content of the constructs, with Pearson's correlation coefficients of 0.92 and 0.90, respectively. These results indicate that tissue-engineered bone with high osteogenic ability can be selected before implantation based on low calcium content of the culture medium, resulting in successful bone formation after implantation. This nondestructive, simple method shows great promise for assessing the osteogenic ability of tissue-engineered bone.

Research Advancements in Porcine Derived Mesenchymal Stem Cells

In the present era of stem cell biology, various animals such as Mouse, Bovine, Rabbit and Porcine have been tested for the efficiency of their mesenchymal stem cells (MSCs) before their actual use for stem cell based application in humans. Among them pigs have many similarities to humans in the form of organ size, physiology and their functioning, therefore they have been considered as a valuable model system for in vitro studies and preclinical assessments. Easy assessability, few ethical issues, successful MSC isolation from different origins like bone marrow, skin, umbilical cord blood, Wharton’s jelly, endometrium, amniotic fluid and peripheral blood make porcine a good model for stem cell therapy. Porcine derived MSCs (pMSCs) have shown greater in vitro differentiation and transdifferention potential towards mesenchymal lineages and specialized lineages such as cardiomyocytes, neurons, hepatocytes and pancreatic beta cells. Immunomodulatory and low immunogenic profiles as shown by autologous and heterologous MSCs proves them safe and appropriate models for xenotransplantation purposes. Furthermore, tissue engineered stem cell constructs can be of immense importance in relation to various osteochondral defects which are difficult to treat otherwise. Using pMSCs successful treatment of various disorders like Parkinson’s disease, cardiac ischemia, hepatic failure, has been reported by many studies. Here, in this review we highlight current research findings in the area of porcine mesenchymal stem cells dealing with their isolation methods, differentiation ability, transplantation applications and their therapeutic potential towards various diseases.

Regeneration of Articular Cartilage by Human ESC-Derived Mesenchymal Progenitors Treated Sequentially with BMP-2 and Wnt5a

The success of cell‐based therapies to restore joint cartilage requires an optimal source of reparative progenitor cells and tight control of their differentiation into a permanent cartilage phenotype. Bone morphogenetic protein 2 (BMP‐2) has been extensively shown to promote mesenchymal cell differentiation into chondrocytes in vitro and in vivo. Conversely, developmental studies have demonstrated decreased chondrocyte maturation by Wingless‐Type MMTV Integration Site Family, Member 5A (Wnt5a). Thus, we hypothesized that treatment of human embryonic stem cell (hESC)‐derived chondroprogenitors with BMP‐2 followed by Wnt5a may control the maturational progression of these cells into a hyaline‐like chondrocyte phenotype. We examined the effects of sustained exposure of hESC‐derived mesenchymal‐like progenitors to recombinant Wnt5a or BMP‐2 in vitro. Our data indicate that BMP‐2 promoted a strong chondrogenic response leading to terminal maturation, whereas recombinant Wnt5a induced a mild chondrogenic response without promoting hypertrophy. Moreover, Wnt5a suppressed BMP‐2‐mediated chondrocyte maturation, preventing the formation of fibrocartilaginous tissue in high‐density cultures treated sequentially with BMP‐2 and Wnt5a. Implantation of scaffoldless pellets of hESC‐derived chondroprogenitors pretreated with BMP‐2 followed by Wnt5a into rat chondral defects induced an articular‐like phenotype in vivo. Together, the data establish a novel role for Wnt5a in controlling the progression from multipotency into an articular‐like cartilage phenotype in vitro and in vivo. Stem Cells Translational Medicine2017;6:40–50

Mesenchymal stem cells to treat diabetic neuropathy: a long and strenuous way from bench to the clinic

As one of the most common complications of diabetes, diabetic neuropathy often causes foot ulcers and even limb amputations. Inspite of continuous development in antidiabetic drugs, there is still no efficient therapy to cure diabetic neuropathy. Diabetic neuropathy shows declined vascularity in peripheral nerves and lack of angiogenic and neurotrophic factors. Mesenchymal stem cells (MSCs) have been indicated as a novel emerging regenerative therapy for diabetic neuropathy because of their multipotency. We will briefly review the pathogenesis of diabetic neuropathy, characteristic of MSCs, effects of MSC therapies for diabetic neuropathy and its related mechanisms. In order to treat diabetic neuropathy, neurotrophic or angiogenic factors in the form of protein or gene therapy are delivered to diabetic neuropathy, but therapeutic efficiencies are very modest if not ineffective. MSC treatment reverses manifestations of diabetic neuropathy. MSCs have an important role to repair tissue and to lower blood glucose level. MSCs even paracrinely secrete neurotrophic factors, angiogenic factors, cytokines, and immunomodulatory substances to ameliorate diabetic neuropathy. There are still several challenges in the clinical translation of MSC therapy, such as safety, optimal dose of administration, optimal mode of cell delivery, issues of MSC heterogeneity, clinically meaningful engraftment, autologous or allogeneic approach, challenges with cell manufacture, and further mechanisms.

Overexpression of Oct4 in porcine ovarian stem/stromal cells enhances differentiation of oocyte-like cells in vitro and ovarian follicular formation in vivo

Background

Recent findings have revealed that the female gonad may have regenerative activity with having germ line stem cells in juveniles and adults. Application of these germ line stem cells could be an alternative therapy for reproductive disorders in regenerative medicine.

Methods

To enhance the potency of differentiation into oocyte-like cells (OLCs) and folliculogenesis, we overexpressed Oct4 in ovarian stem/stromal cell (OvSCs) and examined the cellular properties related to stemness and self-renewal ability and finally demonstrated the ability of in vitro differentiation and folliculogenesis.

Results

Ovarian cortex included putative stem cells in terms of AP activity, cell cycle status, cell proliferation, expression of mesenchymal lineage surface markers and pluripotent transcriptional markers. Further, Oct4 transfected OvSCs (Oct4-OvSCs) were enhanced their AP activity and cell proliferation compared to OvSCs. The potential on in vitro differentiation into OLCs and in vivo folliculogenesis was also evaluated in OvSCs and Oct4-OvSCs, respectively. Oct4-OvSCs possessed higher oogenesis potential in vitro than OvSCs, in terms of expression of germ cell markers by RT-PCR and the number of OLCs. When OvSCs and Oct4-OvSCs were xeno-transplanted into infertile mice ovaries, the OvSCs transplantation induced new primary follicle formation and hormonal levels of estradiol and FSH remained similar to that of normal mice. However, Oct4-OvSCs possessed higher ability for folliculogenesis based on inducing developing follicles with thecal layer and granulosa cells and more similar estradiol level to normal mice.

Conclusions

These findings demonstrated that putative stem cells were present in ovarian cortex and exhibited differentiation ability into OLCs and folliculogenesis in vivo, and Oct4-overexpression enhanced these ability, suggesting their cellular models based on gene therapy in understanding the mechanisms of oogenesis and folliculogenesis, and finally in view of reproductive cell therapy.