Growth factor regulation of proliferation and survival of multipotential stromal cells

Over-Production of Therapeutic Growth Factors for Articular Cartilage Regeneration by Protein Production Platforms and Protein Packaging Cell Lines

Simple Summary

Osteoarthritis (OA) is the most common form of arthritis across the world. Most of the existing drugs for OA treat the symptoms of pain and inflammation. There are no drugs that can dure the disease. There are a number of new treatments for OA including cell therapy and gene therapy. This articles outlines the concept behind TissueGene-C, a new biological drug for OA. This new treatment includes cartilage cells mixed with a genetically modified cell line called GP2-293, which is effectively a “drug factory”, over-producing the growth factors that are important for cartilage regeneration and changing the environment inside joints. The mixture is injected into the affected knee joint. These cells are designed to be short-lived and cannot reproduce. Therefore, after they have done their job, they die and are cleared by immune cells. This is a new and modern approach to treating OA and TissueGene-C is the prototype cell therapy for OA. In the future, it is entirely possible to combine different clones of genetically engineered cells like GP2-293 that have been designed to over-produce a growth factor or biological drug with cells from the cartilage endplate of the intervertebral disc to treat degeneration in the spine.

Abstract

This review article focuses on the current state-of-the-art cellular and molecular biotechnology for the over-production of clinically relevant therapeutic and anabolic growth factors. We discuss how the currently available tools and emerging technologies can be used for the regenerative treatment of osteoarthritis (OA). Transfected protein packaging cell lines such as GP-293 cells may be used as “cellular factories” for large-scale production of therapeutic proteins and pro-anabolic growth factors, particularly in the context of cartilage regeneration. However, when irradiated with gamma or x-rays, these cells lose their capacity for replication, which makes them safe for use as a live cell component of intra-articular injections. This innovation is already here, in the form of TissueGene-C, a new biological drug that consists of normal allogeneic primary chondrocytes combined with transduced GP2-293 cells that overexpress the growth factor transforming growth factor β1 (TGF-β1). TissueGene-C has revolutionized the concept of cell therapy, allowing drug companies to develop live cells as biological drug delivery systems for direct intra-articular injection of growth factors whose half-lives are in the order of minutes. Therefore, in this paper, we discuss the potential for new innovations in regenerative medicine for degenerative diseases of synovial joints using mammalian protein production platforms, specifically protein packaging cell lines, for over-producing growth factors for cartilage tissue regeneration and give recent examples. Mammalian protein production platforms that incorporate protein packaging eukaryotic cell lines are superior to prokaryotic bacterial expression systems and are likely to have a significant impact on the development of new humanized biological growth factor therapies for treating focal cartilage defects and more generally for the treatment of degenerative joint diseases such as OA, especially when injected directly into the joint.

Molecular Beacon Imaging to Visualize Ki67 mRNA for Cell Proliferation Ability

The objective of this study is to visualize the ability of cell proliferation based on molecular beacons (MB). Two types of MB to detect messenger RNA (mRNA) were used. One is a Ki67 MB of a target for cell proliferation ability. The other one is a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) MB as a control of stable fluorescence in cells. To enhance the MB internalization into cells, the MB were incorporated into cationized gelatin nanospheres (cGNS). There was no difference in the physicochemical properties and the cell internalization between the cGNS_{Ki67 MB} and cGNS_{GAP MB}. When basic fibroblast growth factor (bFGF) was added to KUM6 cells of a mouse bone marrow-derived mesenchymal stem cell line, the expression of Ki67 and the cell proliferation increased with the bFGF concentration. After the incubation for the cell internalization of cGNS incorporating MB (cGNS_MB), the cells were further incubated for 24 h with or without different concentrations of bFGF. The fluorescence of cGNS_{Ki67 MB} significantly increased with the increase of bFGF concentration, whereas that of cGNS_{GAP MB} was constant, irrespective of the bFGF concentration. A time-lapse imaging assay revealed a fast enhancement of cGNS_{Ki67 MB} fluorescence after the bFGF addition compared with no bFGF addition. On the other hand, for cGNS_{GAP MB}, a constant fluorescence was observed even at any time point after the bFGF addition. It is concluded that the cGNS_MB system is promising for the chronological visualization of proliferation ability in living cells.

Combinations of growth factors for human mesenchymal stem cell proliferation and osteogenic differentiation

Aims

Here we introduce a wide and complex study comparing effects of growth factors used alone and in combinations on human mesenchymal stem cell (hMSC) proliferation and osteogenic differentiation. Certain ways of cell behaviour can be triggered by specific peptides – growth factors, influencing cell fate through surface cellular receptors.

Methods

In our study transforming growth factor β (TGF-β), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF) were used in order to induce osteogenesis and proliferation of hMSCs from bone marrow. These cells are naturally able to differentiate into various mesodermal cell lines. Effect of each factor itself is pretty well known. We designed experimental groups where two and more growth factors were combined. We supposed cumulative effect would appear when more growth factors with the same effect were combined. The cellular metabolism was evaluated using MTS assay and double-stranded DNA (dsDNA) amount using PicoGreen assay. Alkaline phosphatase (ALP) activity, as early osteogenesis marker, was observed. Phase contrast microscopy was used for cell morphology evaluation.

Results

TGF-β and bFGF were shown to significantly enhance cell proliferation. VEGF and IGF-1 supported ALP activity. Light microscopy showed initial extracellular matrix mineralization after VEGF/IGF-1 supply.

Conclusion

A combination of more than two growth factors did not support the cellular metabolism level and ALP activity even though the growth factor itself had a positive effect. This is probably caused by interplay of various messengers shared by more growth factor signalling cascades.

Cite this article: Bone Joint Res 2020;9(7):412–420.

Mesenchymal Stem/Progenitor Cells: The Prospect of Human Clinical Translation

Mesenchymal stem/progenitor cells (MSCs) are key players in regenerative medicine, relying principally on their differentiation/regeneration potential, immunomodulatory properties, paracrine effects, and potent homing ability with minimal if any ethical concerns. Even though multiple preclinical and clinical studies have demonstrated remarkable properties for MSCs, the clinical applicability of MSC-based therapies is still questionable. Several challenges exist that critically hinder a successful clinical translation of MSC-based therapies, including but not limited to heterogeneity of their populations, variability in their quality and quantity, donor-related factors, discrepancies in protocols for isolation, in vitro expansion and premodification, and variability in methods of cell delivery, dosing, and cell homing. Alterations of MSC viability, proliferation, properties, and/or function are also affected by various drugs and chemicals. Moreover, significant safety concerns exist due to possible teratogenic/neoplastic potential and transmission of infectious diseases. Through the current review, we aim to highlight the major challenges facing MSCs' human clinical translation and shed light on the undergoing strategies to overcome them.

Soluble recombinant human thrombomodulin suppresses inflammation-induced gastrointestinal tumor growth in a murine peritonitis model

Regulatory T cells (Tregs) and transforming growth factor β (TGF-β) are believed to play key roles in both postoperative pro-inflammatory and anti-inflammatory responses of malignancies. Recombinant human thrombomodulin (rTM) is implied to inhibit the interaction between TGF-β and Tregs. The aim of this study is to evaluate the antitumor effects of rTM against gastrointestinal tumors under systemic inflammation. Mice were subjected to cecal ligation and puncture and percutaneous allogeneic tumor implantation. rTM were introduced by percutaneous injection into the abdominal cavity. The effects of rTM were evaluated by weight of implanted tumor, proportion of Tregs in peripheral blood lymphocytes (PBL) and tumor infiltrating lymphocytes (TIL) and temporal evaluation of serum cytokines. The effect of rTM was also evaluated on the in vitro differentiation of naïve T cells into induced Tregs induced by TGF-β and interleukin (IL) -2. rTM significantly inhibited the proliferation of the implanted tumor cells in an inflammation-dependent manner. rTM also reduced the fractions of regulatory T cells and induced regulatory T cells among both PBL and TIL. Temporal evaluation of serum cytokine levels in the model mice showed that rTM significantly suppressed the increases in the serum levels of IL-2 and TGF-β. An in vitro differentiation assay revealed that rTM inhibited the differentiation of naïve T cells into Tregs triggered by IL-2- and TGF-β. rTM has suppressive effects on inflammation-induced gastrointestinal tumor growth by suggestively affecting differentiation of Tregs.

Hepatocyte growth factor and matrix metalloprotease 2 levels in synovial fluid of the knee joint are correlated with clinical outcome of meniscal repair

BACKGROUND

The reoperation rate after primary meniscal repair is about 20%. Thus far, it has remained unclear whether there are distinct individual preconditions that may be associated with a better or worse outcome of this procedure. We therefore analysed typical biochemical mediators in the synovial fluid (SF) of patients with meniscus tear before arthroscopic meniscal refixation and correlated their concentrations to the occurrence of re-rupture after meniscus repair.

METHODS

In this study, 48 patients with meniscus ruptures were included. SF samples were taken intraoperatively prior to arthroscopy. Multiplex enzyme-linked immunosorbent assay (ELISA)-based methods were used to measure hepatocyte growth factor (HGF), interleukin-18 (IL-18), matrix metalloproteinases (MMP) MMP-1, MMP-2, MMP-9 and MMP-13 in the SF. At follow-up, the patients were classified into two groups: surgical success and surgical failure.

RESULTS

Ten out of 48 patients (20.8%) had to undergo revision surgery after meniscal repair (surgical failure). The median HGF in the surgical failure group was 2.4-times higher than in the surgical success group (P = .006), and the median MMP-2 was 1.8 times higher (P = .017). Concentration levels of the other tested proteins were not correlated with the success or failure of the meniscus surgery. There was weak evidence that both markers are indicators of an unsatisfactory healing process for meniscal refixation.

CONCLUSION

These results suggest that HGF and MMP-2 could serve as molecular markers to estimate the chances of healing success of meniscus repair and possibly to individualise therapy in meniscal surgery.

Human adipose-derived stem cell spheroids incorporating platelet-derived growth factor (PDGF) and bio-minerals for vascularized bone tissue engineering

Stem cells with mineralized materials have been used for bone regeneration; however, engineering the complex vascularized structure of the natural bone remains a challenge. Here, we developed platelet-derived growth factor (PDGF) and bio-mineral coated fibers which were then assembled with human adipose-derived stem cells (hADSCs) to form spheroids as building blocks for vascularized bone regeneration. The PDGF incorporated within the spheroid increased the proliferation of hADSCs, which was characterized by Ki-67 staining and DNA contents. Furthermore, the PDGF enhanced not only osteogenic differentiation, but also endothelial differentiation of hADSCs; the cells within the spheroids showed significantly greater gene expression by 2.46 ± 0.14 fold for osteocalcin (OCN) and by 12.85 ± 3.36 fold for von Willebrand factor (vWF) than those without PDGF. Finally, at two months following transplantation of PDGF-incorporated spheroids onto in vivo mouse calvarial defect, the regenerated bone area (42.48 ± 10.84%) was significantly enhanced and the greatest number of capillaries and arterioles with indication of transplanted hADSCs were observed. Moreover, millimeter-scale in vitro tissue prepared by fused assembly of the spheroids exhibited greater mRNA expression-associated to endothelial lineage. Taken together, these findings indicate that stem cell spheroids incorporating PDGF and bio-minerals could be used as a module for successful vascularized bone regeneration.

Cloning of human cord blood-mesenchymal stem cells for isolation of enriched cell population of higher proliferation and differentiation potential

Heterogeneity of Mesenchymal stem cells (MSCs) imposes limitations for their in vitro expansion and accounts for the lack of reproducibility in some clinical studies. So, this study was designed to isolate and enrich clones of multipotent and self-renewing MSCs from cord blood (CB). Enriched clones with higher proliferation and differentiation potential provide regenerative cells suitable for various clinical demands. MSCA and MSCB original (progenitor) cells were isolated from CB samples, and single cells were cloned by limiting dilution method, in mouse embryonic fibroblast conditioned media. Original MSCs and their single-cell derived clones were characterized by identifying their proliferation rate, immunophenotyping of surface antigens, expression of pluripotency and proliferation genes (Oct4, Sox2, Nanog, KLF4, c-Myc, and PDGFRA), and differentiation potential into multiple lineages (osteogenic, adipogenic, and chondrogenic). Some single-cell clones of MSCA showed a higher proliferation rate and greater differentiation potential than their original cells. However, original MSCB cells were of greater proliferation and differentiation potential than their derived single-cell clones, except for one clone which had comparable results. Cloning of MSCs was attainable when cultured in mouse embryonic fibroblast conditioned media. Single clones with higher proliferation and differentiation potential than their original progenitor cells were obtained by cloning of poorly functioning MSCs progenitor cells, enabling the selection of more therapeutically efficacious MSCs with better performance in clinical applications. Moreover, this study draws attention to the importance of CD105 as a possible MSCs biomarker associated with the multilineage commitment of MSCs.

Osteogenesis and bone remodeling: A focus on growth factors and bioactive peptides

Bone is one of the most frequently transplanted tissues. The bone structure and its physiological function and stem cells biology were known to be closely related to each other for many years. Bone is considered a home to the well-known systems of postnatal mesenchymal stem cells (MSCs). These bone resident MSCs provide a range of growth factors (GF) and cytokines to support cell growth following injury. These GFs include a group of proteins and peptides produced by different cells which are regulators of important cell functions such as division, migration, and differentiation. GF signaling controls the formation and development of the MSCs condensation and plays a critical role in regulating osteogenesis, chondrogenesis, and bone/mineral homeostasis. Thus, a combination of both MSCs and GFs receives high expectations in regenerative medicine, particularly in bone repair applications. It is known that the delivery of exogenous GFs to the non-union bone fracture site remarkably improves healing results. Here we present updated information on bone tissue engineering with a specific focus on GF characteristics and their application in cellular functions and tissue healing. Moreover, the interrelation of GFs with the damaged bone microenvironment and their mechanistic functions are discussed.

Computational Modeling of Human Mesenchymal Stromal Cell Proliferation and Extra-Cellular Matrix Production in 3D Porous Scaffolds in a Perfusion Bioreactor: The Effect of Growth Factors

Stem cell expansion on 3D porous scaffolds cultured in bioreactor systems has been shown to be beneficial for maintenance of the original cell functionality in tissue engineering strategies (TE). However, the production of extracellular matrix (ECM) makes harvesting the progenitor cell population from 3D scaffolds a challenge. Medium composition plays a role in stimulating cell proliferation over extracellular matrix (ECM) production. In this regard, a computational model describing tissue growth inside 3D scaffolds can be a great tool in designing optimal experimental conditions. In this study, a computational model describing cell and ECM growth in a perfusion bioreactor is developed, including a description of the effect of a (generic) growth factor on the biological processes taking place inside the 3D scaffold. In the model, the speed of cell and ECM growth depends on the flow-induced shear stress, curvature and the concentrations of oxygen, glucose, lactate, and growth factor. The effect of the simulated growth factor is to differentially enhance cell proliferation over ECM production. After model calibration with historic in-house data, a multi-objective optimization procedure is executed aiming to minimize the total experimental cost whilst maximizing cell growth during culture. The obtained results indicate there are multiple optimum points for the medium refreshment regime and the initial growth factor concentration where a trade-off is made between the final amount of cells and the culture cost. Finally, the model is applied to experiments reported in the literature studying the effects of perfusion-based cell culture and/or growth factor supplementation on cell expansion. The qualitative similarities between the simulation and experimental results, even in the absence of proper model calibration, reinforces the generic character of the proposed modeling framework. The model proposed in this study can contribute to the cost efficient production of cell-based TE products, ultimately contributing to their affordability and accessibility.

Impact of growth factor content on proliferation of mesenchymal stromal cells derived from adipose tissue

Autologous adipose tissue (AT) transfer has gained widespread acceptance and is used for a broad variety of regenerative clinical indications. It is assumed that the successful outcome of AT transfer essentially depends on the amount of autocrine-generated growth factors (GF). It is supposed that several GF enhance and improve the anatomic and functional integration of the transplanted AT grafts at the site of implantation. In the present study we have investigated for the first time the correlation between the concentration of GF of freshly isolated AT and the proliferation and migration capacity of mesenchymal stroma cells (MSCs) derived from the respective AT sample. We here show that the proliferation and migration capacity of MSCs strongly depends on the GF content of the AT the cells were isolated from but in an inversely proportional manner. The lower the GF content of an AT sample was, the higher was the proliferation and migration capacity of the respective MSC population contained in the AT and vice versa. Furthermore, we found that supplementation with recombinant GFs only in the case of AT samples with low but not with higher growth factor contents led to a significant enhancement of proliferation and migration of the AT-resident MSCs. As we further show, this inefficiency of GFs to enhance MSC proliferation and migration in AT samples with high GF contents indicates a GF-mediated negative feedback mechanism leading to an impaired GF signaling in MSC obtained from those AT samples. Our results might explain why the successful use of AT grafting is frequently limited by low and unpredictable survival rates, and we suggest to use the knowledge of GF content of harvested AT as a predictive clinical parameter for risk assessment of the therapeutic outcome of autologous AT transfer.

Mesenchymal Stem Cell/Multipotent Stromal Cell Augmentation of Wound Healing: Lessons from the Physiology of Matrix and Hypoxia Support

Cutaneous wounds requiring tissue replacement are often challenging to treat and result in substantial economic burden. Many of the challenges inherent to therapy-mediated healing are due to comorbidities of disease and aging that render many wounds as chronic or nonhealing. Repeated failure to resolve chronic wounds compromises the reserve or functioning of localized reparative cells. Transplantation of mesenchymal stem cells/multipotent stromal cells (MSCs) has been proposed to augment the reparative capacity of resident cells within the wound bed to overcome stalled wound healing. However, MSCs face a variety of challenges within the wound micro-environment that curtail their survival after transplantation. MSCs are naturally pro-angiogenic and proreparative, and thus numerous techniques have been attempted to improve their survival and efficacy after transplantation, many with little impact. These setbacks have prompted researchers to re-examine the normal wound bed physiology, resulting in new approaches to MSC transplantation using extracellular matrix proteins and hypoxia preconditioning. These studies have also led to new insights on associated intracellular mechanisms, particularly autophagy, which play key roles in further regulating MSC survival and paracrine signaling. This review provides a brief overview of cutaneous wound healing with discussion on how extracellular matrix proteins and hypoxia can be utilized to improve MSC retention and therapeutic outcome.

Harnessing mesenchymal stem cell secretome: Effect of extracellular matrices on proangiogenic signaling

The low engraftment and retention rate of mesenchymal stem cells (MSCs) at the target site indicates that the potential benefits of MSC-based therapies can be attributed to their paracrine signaling. In this study, the extracellular matrices (ECMs) deposited by bone marrow-derived human MSCs in the presence and absence of ascorbic acid was characterized. MSCs were seeded on top of decellularized ECM (dECM) and the concentrations of proangiogenic and antiangiogenic molecules released in culture (conditioned) media was compared. Effects of ECM derived from MSCs with different passage numbers on MSC secretome was also investigated. Our study revealed that the expression of proangiogenesis-related factors were upregulated when MSCs were harvested on dECMs, irrespective of media supplementation, as compared with those cultured on tissue culture plates. In addition, dECM generated in the presence of ascorbic acid promoted the expression of proangiogenic molecules as compared with dECM-derived in absence of media supplementation. Further, it was observed that the effectiveness of dECM to stimulate proangiogenic signaling of MSCs was reduced as cell passage number was increased from P3 to P5. The proliferation as well as capillary morphogenesis of human umbilical vein endothelial cells (HUVECs) in the presence of conditioned media were enhanced compared with the normal HUVECs culture media. These data indicate that the secretory signatures of MSCs and consequently, the therapeutic efficacy of MSCs can be regulated by presentation of dECM composition and variation of its composition.

Growth Factor Gene-Modified Mesenchymal Stem Cells in Tissue Regeneration

There have been marked changes in the field of stem cell therapeutics in recent years, with many clinical trials having been conducted to date in an effort to treat myriad diseases. Mesenchymal stem cells (MSCs) are the cell type most frequently utilized in stem cell therapeutic and tissue regenerative strategies, and have been used with excellent safety to date. Unfortunately, these MSCs have limited ability to engraft and survive, reducing their clinical utility. MSCs are able to secrete growth factors that can support the regeneration of tissues, and engineering MSCs to express such growth factors can improve their survival, proliferation, differentiation, and tissue reconstructing abilities. As such, it is likely that such genetically modified MSCs may represent the next stage of regenerative therapy. Indeed, increasing volumes of preclinical research suggests that such modified MSCs expressing growth factors can effectively treat many forms of tissue damage. In the present review, we survey recent approaches to producing and utilizing growth factor gene-modified MSCs in the context of tissue repair and discuss its prospects for clinical application.

Non-thermal atmospheric pressure plasma induces epigenetic modifications that activate the expression of various cytokines and growth factors in human mesoderm-derived stem cells

Non-thermal atmospheric pressure plasma (NTAPP) has been reported to induce wound healing, activation of immune cells, and proliferation of mesoderm-derived adult stem cells in human. However, the mechanism by which NTAPP activates these physiological effects is poorly understood. Here, we examined whole genome expression profiles of adipose tissue-derived stem cells (ASCs), the proliferation of which is induced by NTAPP. NTAPP upregulated the expression of genes for cytokine and growth factor, but downregulated genes in apoptotic pathways. When ASCs were treated with NTAPP in the presence of a nitric oxide (NO) scavenger, the expression of various cytokines and growth factors decreased, suggesting that NO is primarily responsible for the enhanced cytokine and growth factor expression induced by NTAPP. Increased histone deacetyl transferase 1 (HDAC1) and decreased acetylated histone 3 were detected in NTAPP-treated ASCs. Similarly, ASCs pre-treated with HDAC, DNA methylation, or histone methylation inhibitors had reduced expression of cytokines and growth factors after NTAPP treatment. Taken together, these results strongly suggest that NTAPP induces epigenetic modifications that activate the expression of cytokines and growth factors, explaining how NTAPP acts as an efficient tool in regenerative medicine to stimulate stem cell proliferation, to activate immune cells, and to recover wounds.

A human epidermal growth factor-curcumin bandage bioconjugate loaded with mesenchymal stem cell for in vivo diabetic wound healing

Bone-marrow-derived mesenchymal stem cells (MSCs) are of growing interest for the treatment of diabetic wound healing. However, they are often associated with poor proliferation and viability at the wounded site. Here, it is reported the use of human epidermal growth factor -curcumin bandage bioconjugate (EGF-Cur B) loaded with MSCs (MSCs-EGF-Cur B) at the wounded site for diabetic wound healing. Conjugation efficiency of EGF was determined by FTIR and XPS, surface morphology was analyzed by SEM and AFM and hydrophilicity by contact angle. Chemical integrity of curcumin with the polymeric matrix was studied by FTIR and, antiinflamatory and biocompatibility of EGF-Cur B were determined by TNF α ELISA and MTT study respectively. The culture of MSCs over EGF-Cur B enhanced MSC viability and expression of transcription factors associated with the maintenance of pluripotency and self-renewal (OCT¾, SOX2, and Nanog) as compared to MSCs grown in standard conditions. Its therapeutic effect was examined on diabetic full-thickness excisional wound model in terms of size and histological examination. Synergetic combinational approach especially when treated with MSCs-EGF-Cur B significantly enhanced wound closure by increasing granulation tissue formation, collagen deposition, and angiogenesis as compared to other groups. In conclusion, biocompatible therapeutic MSCs-EGF-Cur B might have great application for diabetic wound healing in the near future.

Recombinant platelet-derived growth factor-BB and hyaluronic acid stimulates knee cartilage regeneration by forming higher chondrocytes count and lower YKL-40 level in rats model

OBJECTIVE

Osteoarthritis is caused by cartilage degeneration arising from cartilage degradation of type II collagen which synthesis also deteriorated. Nowadays, osteoarthritis is still difficult to handle because of the irreversibility and progressivity of the disease. Regenerative therapy offers a great challenge and better result for osteoarthritis treatment. This study aims to prove that the administration of recombinant platelet-derived growth factor-BB (rrPDGF-BB) with hyaluronic acid (HA) can stimulate the higher forms of chondrocyte and lower the YKL-40 levels as a specific marker of cartilage degradation in mouse knee osteoarthritis model.

METHOD

This was an experimental study, post-test only control group design using white Wistar rats as subjects that were induced by monosodium iodoacetate (MIA) to create osteoarthritis (OA). The treatment group was given treatment group was given rrPDGF-BB and HA, while no such treatment was given to the control group. The chondrocyte cell count was examined with routine histopathology, and YKL-40 levels were calculated by ELISA.

RESULT

Statistical analysis using independent t-test showed that the mean difference in the number of cell counts of chondrocytes was significantly higher than the control group. While the mean difference of YKL-40 level in the treatment group was significantly lower compared to the control group with.

CONCLUSION

We conclude that the administration of rrPDGF-BB and HA in mouse knee joint osteoarthritis model have a regenerative effect on knee joint cartilage characterized by a higher number of chondrocytes and lower YKL-40 levels.

Orchestrating stem cell fate: Novel tools for regenerative medicine

Mesenchymal stem cells are undifferentiated cells able to acquire different phenotypes under specific stimuli. In vitro manipulation of these cells is focused on understanding stem cell behavior, proliferation and pluripotency. Latest advances in the field of stem cells concern epigenetics and its role in maintaining self-renewal and differentiation capabilities. Chemical and physical stimuli can modulate cell commitment, acting on gene expression of Oct-4, Sox-2 and Nanog, the main stemness markers, and tissue-lineage specific genes. This activation or repression is related to the activity of chromatin-remodeling factors and epigenetic regulators, new targets of many cell therapies. The aim of this review is to afford a view of the current state of in vitro and in vivo stem cell applications, highlighting the strategies used to influence stem cell commitment for current and future cell therapies. Identifying the molecular mechanisms controlling stem cell fate could open up novel strategies for tissue repairing processes and other clinical applications.

Cytokine Selection of MSC Clones with Different Functionality

Mesenchymal stromal cells (MSCs) are used in many clinical applications. However, ex vivo expansion is required to reach clinically relevant cell numbers, which might lead to selection of clones with different characteristics. To follow clonal selection, we transduced MSC progenitors in umbilical cord pieces (UCPs) with vectors encoding fluorescent proteins and genetic barcodes. After marked MSC cultures grew out from UCPs, we investigated the influence of cytokines on MSC functionality. Specific cytokine conditions selected for clones from common progenitors. MSC secretome analyses revealed differences dependent on the culture conditions used. Clones expanded in human serum containing culture medium secreted a plethora of growth factors. When expanded in the same medium containing TGF-β, MSCs secreted negligible amounts of cytokines but at the same time led to an increased human chimerism after hematopoietic stem cell transplantation into immunodeficient mice. Our results suggest a major influence of cytokine additives on MSC functionality.

Platelet-rich gel-incorporated silk scaffold promotes meniscus regeneration in a rabbit total meniscectomy model

Aim: To investigate whether platelet-rich gel (PRG) incorporation could promote meniscal regeneration of the silk scaffold. Materials & methods: A PRG-incorporated silk sponge was fabricated for reconstruction of the meniscus in a rabbit meniscectomy model. Subsequently, characterization of the scaffold, as well as the in vitro cytocompatibility and in vivo function was evaluated. Results: Our results showed that the PRG-incorporated silk scaffold provided a sustained release of TGF-β1 over 1 week. The PRG enhanced the cytocompatibility in vitro and cell infiltration in vivo of the silk sponge. Meanwhile, the implantation of the composite in situ ameliorated the cartilage degeneration in knee at 3 months. Conclusion: These findings indicated that PRG-incorporated silk scaffold could promote functional regeneration of the meniscus and effectively prevented subsequent osteoarthritis after meniscectomy.

The pan-therapeutic resistance of disseminated tumor cells: Role of phenotypic plasticity and the metastatic microenvironment

Cancer metastasis is the leading cause of mortality in patients with solid tumors. The majority of these deaths are associated with metastatic disease that occurs after a period of clinical remission, anywhere from months to decades following removal of the primary mass. This dormancy is prominent in cancers of the breast and prostate among others, leaving the survivors uncertain about their longer-term prognosis. The most daunting aspect of this dormancy and re-emergence is that the micrometastases in particular, and even large lethal outgrowths are often show resistance to agents to which they have not been exposed. This suggests that in addition to specific mutations that target single agents, there also exist adaptive mechanisms that provide this pan-resistance. Potential molecular underpinnings of which are the topic of this review.

Dual Aptamer-Functionalized in Situ Injectable Fibrin Hydrogel for Promotion of Angiogenesis via Codelivery of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor-BB

In situ injectable hydrogels hold great potential for in vivo applications such as drug delivery and regenerative medicine. However, it is challenging to ensure stable sequestration and sustained release of loaded biomolecules in these hydrogels. As aptamers have high binding affinities and specificities against target biomolecules, we studied the capability of aptamers in functionalizing in situ injectable fibrin (Fn) hydrogels for in vivo delivery of two growth factors including vascular endothelial growth factor (VEGF) and platelet-derived growth factor-BB (PDGF-BB). The results show that aptamer-functionalized fibrinogen (Fg) could form in situ injectable Fn hydrogels with porous structures. The aptamer-functionalized Fn hydrogels could sequester more VEGF and PDGF-BB than the native Fn and release these growth factors in a sustained manner with high bioactivity. After the aptamer-functionalized Fn hydrogels were subcutaneously injected into mice, the codelivery of VEGF and PDGF-BB could promote the growth of mature blood vessels. Therefore, this study has successfully demonstrated that aptamer-functionalized in situ injectable hydrogels hold great potential for in vivo codelivery of multiple growth factors and promotion of angiogenesis .

An improved method of culturing somatotropic cells from rat adenohypophysis

This study aimed to propose a simple and practical method for culturing primary rat somatotropic cells in vitro free of pericytes contamination. Rat adenohypophyses were randomly divided into two groups. An improved method was used in group A (digesting adenohypophysis with 0.25% trypsin-EDTA, followed by removing pericytes by double filtration and using serum-free medium for culturing somatotropic cells). The traditional method was used in group B (digesting adenohypophysis with 0.35% collagenase, using serum medium for culturing somatotropic cells, and removing pericytes by changing the culture dish). The numbers and viability of somatotropic cells were higher in group A than in group B after 6 days. GH secretion of somatotropic cells was also higher in group A than in group B. Besides, the pericytes grew rapidly only in group B after 3 days. α-SMA, type I collagen, and type III collagen had weaker expression in group A. Also, the viability of pericytes decreased in group A. The improved method could solve the problem of pericytes contamination, and the culture of primary rat somatotropic cells in vitro was successful. This method can be used for other primary cultures with pericytes contamination.

Spontaneous differentiation of periodontal ligament stem cells into myofibroblast during ex vivo expansion

Periodontitis is characterized by the chronic inflammation and destruction of tooth-supporting tissues. Periodontal ligament stem cell (PDLSC) is the mesenchymal stem cell (MSC) population isolated from periodontal ligament, which is the key tissue for regeneration of periodontal tissues. Although transplantation of PDLSCs is proposed as novel regenerative therapy, limited information is available, regarding the characteristic change of PDLSCs during ex vivo expansion. In this study, we encountered morphological change of PDLSCs during standard cell culture and aimed to investigate the change of PDLSCs in stem cell characteristics and to search for the culture condition to maintain stem cell properties. Characteristics of PDLSCs were examined using in vitro osteoblast and adipocyte differentiation. Myofibroblast differentiation was confirmed using immunohistochemistry and collagen gel contraction assay. Replicative senescence was examined by β-gal staining. PDLSCs changed their morphology from spindle to flat and wide during ex vivo expansion. After the morphological change, PDLSCs showed several features of myofibroblast including extensive stress fiber formation, contraction activity, and myofibroblast marker expression. Upon the morphological change, osteoblastic and adipocyte differentiation capacity were reduced and expression of stem cell-related genes were decreased. β-Gal staining was not always correlated with the morphological change of PDLSCs. Moreover, exogenous addition of bFGF and PDGF-BB served to maintain spindle shape and osteoblastic differentiation potential of PDLSCs. This study demonstrates that spontaneous differentiation of PDLSCs during ex vivo expansion and may provide the important information of cell culture condition of PDLSCs for clinical use.

Spontaneous Differentiation of Human Neural Stem Cells on Nanodiamonds

The potential use of stem cells in regenerative medicine requires the ability to be able to control stem cell fate as cellular networks are developed. Here, nanodiamonds (≈10 nm) are supported on glass and shown to be an excellent host for the attachment and proliferation of human neural stem cells. Moreover, it is shown that spontaneous differentiation into neurons occurs on nanodiamonds. The use of variously oxygen terminated and hydrogen terminated nanodiamonds has been explored. It is shown that O-ND monolayers promote the differentiation of human neural stem cells into neurons with increased total neurite length, degree of branching, and density of neurites when compared with H-NDs or the glass control. The total number of neurites and total neurite length expressing MAP2, a protein enriched in dendrites, is over five times higher for spontaneously differentiated neurones on the O-NDs compared to the control. The fact that inexpensive nanodiamonds can be attached through simple sonication from water on 2D and 3D shapes indicates significant promise for their potential as biomaterials in which neuro-regenerative diseases can be studied.

Reciprocal modulation of cell functions upon direct interaction of adipose mesenchymal stromal and activated immune cells

The interaction of adipose mesenchymal stromal cells (ASCs) and allogeneic peripheral blood mononuclear cells (PBMCs) is regulated either through direct or paracrine mechanisms. Here, we examined the impact of direct contact in reciprocal regulation of ASC-PBMC functions. Activated PBMCs in vitro induced ASC immunomodulatory activity, while direct and paracrine intercellular interactions regulated PBMCs themselves: the functional state of the organelles was altered, and activation decreased. Direct contact with immune cells affected the activity of ASC intracellular compartments, in particular, reactive oxygen species (ROS) production, and decreased the growth rate. Some ASC properties, including motility, intercellular adhesion molecule-1 (ICAM-1), and major histocompatibility complex class I and II antigens (HLA-ABC and HLA-DR, respectively) expression, did not depend on contact with PBMCs and were only regulated by paracrine means. Direct ASC and PBMC contact favoured an angiogenesis-supportive microenvironment, possibly due to the greater production of VEGF by ASCs; this microenvironment also contained a higher leukemia inhibitory factor (LIF) level. Thus, a change in the functional activity of ASCs and PBMCs upon interaction promoted the formation of an immunosuppressive, anti-inflammatory, and proangiogenic microenvironment. This environment could help resolve inflammation and further restore damaged tissue. SIGNIFICANCE OF THE STUDY: Numerous studies have demonstrated the beneficial effects of transplanted mesenchymal stromal cells, particularly ASCs, for the treatment of a number of autoimmune diseases as well as various tissue injuries. To improve the efficiency of these methods, it is necessary to understand the principal events that occur when ASCs are introduced, primarily the molecular mechanisms of interaction between ASCs and the recipient immune system. We demonstrated that an anti-inflammatory, immunosuppressive, and angiostimulatory shift in the paracrine profile upon the interaction of activated PBMCs and ASCs changes the functional activity of both cell types, a phenomenon that is potentiated by direct cell-cell contact.

Refined assessment of the impact of cell shape on human mesenchymal stem cell differentiation in 3D contexts

Numerous studies have demonstrated that the differentiation potential of human mesenchymal stem cells (hMSCs) can be modulated by chemical and physical cues. In 2D contexts, inducing different cell morphologies, by varying the shape, area and/or curvature of adhesive islands on patterned surfaces, has significant effects on hMSC multipotency and the onset of differentiation. In contrast, in vitro studies in 3D contexts have suggested that hMSC differentiation does not directly correlate with cell shape. However, in 3D, the effects of cell morphology on hMSC differentiation have not yet been clearly established due to the chemical and physical properties being intertwined in 3D matrices. In this work, we studied the effects of round or elongated cell morphologies on hMSC differentiation independently of scaffold composition, modulus, crosslink density and cell-mediated matrix remodeling. The effects of cell shape on hMSC lineage progression were studied using three different cell culture media compositions and two values of scaffold rigidity. Differences in cell shape were achieved using interpenetrating polymer networks (IPNs). The mechanical and diffusional properties of the scaffolds and cell-matrix interactions were characterized. In addition, cell responses were evaluated in terms of cell spreading via gene and protein expression of differentiation markers. Cumulative results support, and extend upon previous work indicating that cell shape alone in 3D contexts does not significantly modulate hMSC differentiation, at least for the scaffold chemistry, range of modulus and culture conditions explored in this study. STATEMENT OF SIGNIFICANCE: In 2D contexts, inducing different cell shapes, by varying the curvature, area size and shape of a patterned surface, has significant effects on hMSC multipotency and the onset of cell differentiation. In contrast, in vitro studies in 3D contexts have suggested that hMSC differentiation does not directly correlate with cell shape. However, in 3D, the effects of cell morphology on hMSC differentiation have not yet been clearly established due to the chemical and physical properties being intertwined in 3D matrices. In this work, we studied the effects of round or elongated cell morphologies on the differentiation of hMSCs independently of scaffold composition, modulus, crosslink density and cell mediated matrix remodeling. Cumulative results support, and extend upon previous work indicating that cell shape alone in 3D contexts does not significantly modulate hMSCs differentiation commitment.

Recombinant platelet derived growth factor-BB and hyaluronic acid effect in rat osteoarthritis models

Osteoarthritis (OA) arises from imbalance of cartilage metabolism between the synthesis and degradation of type II collagen by the chondrocyte. Collagen type II degradation is characterized by increase in the biomarker of C-telopeptide fragment of type II collagen (CTX-II), while the anabolic process of cartilage is characterized by an increase in the biosynthesis of procollagen amino terminal N-propeptide type IIA (PIIANP). Platelet derived growth factor (PDGF) with Hyaluronic Acid (HA) as a potent growth factor can be used to stimulate the higher formation of chondrocyte and PIIANP levels and lower CTX-II levels in mouse knee osteoarthritis model.

Enhanced Osteogenesis of Bone Marrow-Derived Mesenchymal Stem Cells by a Functionalized Silk Fibroin Hydrogel for Bone Defect Repair

Silk fibroin (SF) from Bombyx mori is a promising natural material for the synthesis of biocompatible and biodegradable hydrogels for use in biomedical applications from tissue engineering to drug delivery. However, weak gelation performance and the lack of biochemical cues to trigger cell proliferation and differentiation currently significantly limit its application in these areas. Herein, a biofunctional hydrogel containing SF (2.0%) and a small peptide gelator (e.g., NapFFRGD = 1.0 wt%) is generated via cooperative molecular self-assembly. The introduction of NapFFRGD to SF is shown to significantly improve its gelation properties by lowering both its threshold gelation concentration to 2.0% and gelation time to 20 min under physiological conditions (pH = 7.4, 37 °C), as well as functionalizing the SF hydrogel with cell-adhesive motifs (e.g., RGD). Besides mediating cell adhesion, the RGD ligands incorporated within the SF-RGD gel promote the osteogenic differentiation of bone marrow-derived mesenchymal stem cells encapsulated within the gel matrix, leading to bone regeneration in a mouse calvarial defect model, compared with a blank SF gel (2.0%, pH = 7.4). This work suggests that SF could be easily tailored with bioactive peptide gelators to afford bioactive hydrogels with favorable microenvironments for tissue regeneration applications.

Soluble matrix protein is a potent modulator of mesenchymal stem cell performance

We challenge the conventional designation of structural matrix proteins primarily as supporting scaffolds for resident cells. The extracellular matrix protein tropoelastin is classically regarded as a structural component that confers mechanical strength and resilience to tissues subject to repetitive elastic deformation. Here we describe how tropoelastin inherently induces a range of biological responses, even in cells not typically associated with elastic tissues and in a manner unexpected of typical substrate-dependent matrix proteins. We show that tropoelastin alone drives mesenchymal stem cell (MSC) proliferation and phenotypic maintenance, akin to the synergistic effects of potent growth factors such as insulin-like growth factor 1 and basic fibroblast growth factor. In addition, tropoelastin functionally surpasses these growth factors, as well as fibronectin, in allowing substantial media serum reduction without loss of proliferative potential. We further demonstrate that tropoelastin elicits strong mitogenic and cell-attractive responses, both as an immobilized substrate and as a soluble additive, via direct interactions with cell surface integrins αvβ3 and αvβ5. This duality of action converges the long-held mechanistic dichotomy between adhesive matrix proteins and soluble growth factors and uncovers the powerful, untapped potential of tropoelastin for clinical MSC expansion and therapeutic MSC recruitment. We propose that the potent, growth factor-like mitogenic and motogenic abilities of tropoelastin are biologically rooted in the need for rapid stem cell homing and proliferation during early development and/or wound repair.

Characterization of the Kinetics and Mechanism of Degradation of Human Mesenchymal Stem Cell-Laden Poly(ethylene glycol) Hydrogels

Human mesenchymal stem cells (hMSCs) are motile cells that migrate from their native niche to wounded sites where they regulate inflammation during healing. New materials are being developed as hMSC delivery platforms to enhance wound healing. To act as an effective wound healing material, the hydrogel must degrade at the same rate as tissue regeneration, while maintaining a high cell viability. This work determines the kinetics and mechanism of cell-mediated degradation in hMSC-laden poly(ethylene glycol) (PEG) hydrogels. We use a well-established hydrogel scaffold that is composed of a backbone of four-arm star PEG functionalized with norbornene that is cross-linked with a matrix metalloproteinase (MMP) degradable peptide. This peptide sequence is cleaved by cell-secreted MMPs, which allow hMSCs to actively degrade the hydrogel during motility. Three mechanisms of degradation are characterized: hydrolytic, noncellular enzymatic and cell-mediated degradation. We use bulk rheology to characterize hydrogel material properties and quantify degradation throughout the entire reaction. Hydrolysis and noncellular enzymatic degradation are first characterized in hydrogels without hMSCs, and follow first-order and Michaelis-Menten kinetics, respectively. A high cell viability is measured in hMSC-laden hydrogels, even after shearing on the rheometer. After confirming hMSC viability, bulk rheology characterizes cell-mediated degradation. When comparing cell-mediated degradation to noncellular degradation mechanisms, cell-mediated degradation is dominated by enzymatic degradation. This indicates hydrogels with hMSCs are degraded primarily due to cell-secreted MMPs and very little network structure is lost due to hydrolysis. Modeling cell-mediated degradation provides an estimate of the initial concentration of MMPs secreted by hMSCs. By changing the concentration of hMSCs, we determine the initial MMP concentration increases with increasing hMSC concentration. This work characterizes the rate and mechanism of scaffold degradation, giving new insight into the design of these materials as implantable scaffolds.

A Thin Layer of Decellularized Porcine Myocardium for Cell Delivery

Decellularized porcine myocardium has shown many benefits as a cell delivery scaffold for cardiac therapy. However, using full thickness decellularized myocardium as cardiac patch may lead to poor viability and inhomogeneous distribution of delivered cells, due to perfusion limitations. In this study, we explored the feasibility of decellularized porcine myocardial slice (dPMS) to construct a vascularized cardiac patch for cell delivery. Decellularized porcine myocardium was sliced into thin layers (thickness~300 µm). Adipose-derived Stem cells (ASCs) obtained from rat and pig were seeded on dPMS. The viability, infiltration, and differentiation of seeded ASCs were examined. The mechanical properties of dPMSs of various thickness and native myocardium were tested. We noticed dPMS supported attachment and growth of rat and pig ASCs. Both rat and pig ASCs showed high viability, similar patterns of proliferation and infiltration within dPMS. Rat ASCs showed expression of early-endothelial markers followed by mature-endothelial marker without any additional inducers on dPMS. Using rat myocardial infarction model, we delivered ASCs using dPMS patched to the infarcted myocardium. After 1 week, a higher number of transplanted cells were present in the infarcted area when cells were delivered using dPMS versus direct injection. Compared with MI group, increased vascular formation was also observed.

Regeneration of different types of tissues depends on the interplay of stem cells-laden constructs and microenvironments in vivo

The ability of repair and regeneration of tissues or organs has been significantly improved by using biomaterials-based constructs. Our previous studies found the regeneration of both articular cartilage and subchondral bone by implantation of a poly(lactide-co-glycolide) (PLGA)/fibrin gel/bone marrow stem cells (BMSCs)/(lipofectamine/pDNA-transforming growth factor (TGF)-β1) construct in vivo, without the step of pre-induced differentiation of the laden stem cells in vitro. To substantiate the ability to regenerate multi-types of tissues by the same constructs, in this study the constructs were implanted into three types of tissues or tissue defects in vivo, including subcutaneous fascia layer, and ear cartilage and eyelid tarsal plate defects. The ear cartilage and eyelid tarsal plate defects were fully regenerated 8 w post-implantation, showing a similar morphology to the corresponding native tissues. In the neo ear cartilage, abundant chondrocytes with obvious lacunas and cartilage-specific extracellular matrices (ECMs) were found. Neo eyelid tarsal plate with mature meibomian gland acinar units was regenerated. Furthermore, expressions of the ECMs-specific genes and proteins, as well as the cell behavior modulatory factors, Sry related HMG box 9 (Sox9) and TGF-β1 were significantly up-regulated in the regenerated ear cartilages and eyelid tarsal plate than those in the subcutaneously implanted constructs, which were filled with fibrocytes, inflammatory cells, obvious vascularization and slight ECMs deposition. These results confirm firmly the ability to regenerate multi-types of tissues by a stem cells-laden construct via adapting to the microenvironments of corresponding tissues.

1H-NMR and MALDI-TOF MS as metabolomic quality control tests to classify platelet derived medium additives for GMP compliant cell expansion procedures

Introduction

Ex vivo cell expansion under Good Manufacturing Practice (GMP) guidelines can be performed using medium additives containing human growth factors from platelets. These products can differently affect proliferation of adipose mesenchymal stromal stem cells (ASC). Qualification of medium additive performance is required for validation under GMP regulations: assessment of growth factor concentrations is not sufficient to predict the biological activity of the product batch. Proton nuclear magnetic resonance spectrometry (¹H-NMR) and matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF MS) provide wide molecular characterization of samples.

Aims

We aimed to assess if ¹H-NMR and MALDI-TOF MS techniques can be used as quality control test potentially predicting the impact of a medium additive on cell proliferation.

Methods

We tested the impact on ASC growth rate (cell proliferation assessment and cell morphology analysis) of four medium additives, obtained by different methods from human platelet apheresis product. In order to classify each medium additive, we evaluated growth factor concentrations and spectra obtained by ¹H-NMR and by MALDI-TOF MS.

Results

Medium additive obtained by CaCl₂ activation of platelet rich products induced higher proliferation rate vs additive derived from platelet depleted ones. Additives obtained by freeze-and-thaw methods weakly induced ASC proliferation. As expected, principal component analysis of growth factor concentrations did not unravel specific biochemical features characterizing medium additives in relation with their biological activity. Otherwise, while ¹H-NMR showed a partial resolution capacity, analysis of MALDI-TOF MS spectra allowed unambiguous distinction between the medium additives we used to differently stimulate cell growth in vitro.

Discussion

MALDI-TOF and, despite limitations, ¹H-NMR are promising cost effective and reliable quality controls to classify the potential of a medium additive to promote ASC growth. This can represent, after further investigations and appropriate validation, a significant advantage for GMP compliant manufacturing of advanced cell therapy products.

Differentiation of Human Tonsil-Derived Mesenchymal Stem Cells into Schwann-Like Cells Improves Neuromuscular Function in a Mouse Model of Charcot-Marie-Tooth Disease Type 1A

Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited motor and sensory neuropathy, and is caused by duplication of PMP22, alterations of which are a characteristic feature of demyelination. The clinical phenotype of CMT1A is determined by the degree of axonal loss, and patients suffer from progressive muscle weakness and impaired sensation. Therefore, we investigated the potential of Schwann-like cells differentiated from human tonsil-derived stem cells (T-MSCs) for use in neuromuscular regeneration in trembler-J (Tr-J) mice, a model of CMT1A. After differentiation, we confirmed the increased expression of Schwann cell (SC) markers, including glial fibrillary acidic protein (GFAP), nerve growth factor receptor (NGFR), S100 calcium-binding protein B (S100B), glial cell-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF), which suggests the differentiation of T-MSCs into SCs (T-MSC-SCs). To test their functional efficiency, the T-MSC-SCs were transplanted into the caudal thigh muscle of Tr-J mice. Recipients’ improved locomotive activity on a rotarod test, and their sciatic function index, which suggests that transplanted T-MSC-SCs ameliorated demyelination and atrophy of nerve and muscle in Tr-J mice. Histological and molecular analyses showed the possibility of in situ remyelination by T-MSC-SCs transplantation. These findings demonstrate that the transplantation of heterologous T-MSC-SCs induced neuromuscular regeneration in mice and suggest they could be useful for the therapeutic treatment of patients with CMT1A disease.

Short-Term Outcomes of Treatment of Hip Osteoarthritis With 4 Bone Marrow Concentrate Injections: A Case Series

The use of mesenchymal stem cells from bone marrow concentrate (BMC) has become an increasingly popular option as an alternative to total joint replacement. Although there is evidence to support the use of BMC injections to improve quality of life for patients with knee osteoarthritis (OA), there is limited evidence to support its use in patients with hip OA. This case series provides the short-term outcomes of 4 hip OA patients who each underwent 4 BMC injections. On average, the last follow-up was administered 3.5 months after the first injection. The results show that patients experienced decreased resting and active pain compared with baseline and mean 72.4% total overall improvement. Patients also reported less difficulty in performing daily activities following the procedure. These encouraging results warrant further research to better understand the effects of BMC injections on hip OA.

Transplanted interleukin-4--secreting mesenchymal stromal cells show extended survival and increased bone mineral density in the murine femur

BACKGROUND

Mesenchymal stromal cell (MSC)-based therapy has great potential to modulate chronic inflammation and enhance tissue regeneration. Crosstalk between MSC-lineage cells and polarized macrophages is critical for bone formation and remodeling in inflammatory bone diseases. However, the translational application of this interaction is limited by the short-term viability of MSCs after cell transplantation.

METHODS

Three types of genetically modified (GM) MSCs were created: (1) luciferase-expressing reporter MSCs; (2) MSCs that secrete interleukin (IL)-4 either constitutively; and (3) MSCs that secrete IL-4 as a response to nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) activation. Cells were injected into the murine distal femoral bone marrow cavity. MSC viability and bone formation were examined in vivo. Cytokine secretion was determined in a femoral explant organ culture model.

RESULTS

The reporter MSCs survived up to 4 weeks post-implantation. No difference in the number of viable cells was found between high (2.5 × 10⁶) and low (0.5 × 10⁶) cell-injected groups. Injection of 2.5 × 10⁶ reporter MSCs increased local bone mineral density at 4 weeks post-implantation. Injection of 0.5 × 10⁶ constitutive IL-4 or NFκB-sensing IL-4-secreting MSCs increased bone mineral density at 2 weeks post-implantation. In the femoral explant organ culture model, LPS treatment induced IL-4 secretion in the NFκB-sensing IL-4-secreting MSC group and IL-10 secretion in all the femur samples. No significant differences in tumor necrosis factor (TNF)α and IL-1β secretion were observed between the MSC-transplanted and control groups in the explant culture.

DISCUSSION

Transplanted GM MSCs demonstrated prolonged cell viability when transplanted to a compatible niche within the bone marrow cavity. GM IL-4-secreting MSCs may have great potential to enhance bone regeneration in disorders associated with chronic inflammation.

From "Bench to Bedside": Current Advancement on Large-Scale Production of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are the primary cell source in cell therapy and regenerative medicine due to its extraordinary self-renewing capacity and multilineage differentiation potential. Clinical trials involving MSCs are being conducted in a range of human diseases and the number of registered cases is continuously increasing. However, a wide gap exists between the number of MSCs obtainable from the donor site and the number required for implantation to damage tissues, and also between MSC scalability and MSC phenotype stability. The clinical translation of MSCs necessitates a scalable expansion bioprocess for the biomanufacturing of therapeutically qualified cells. This review presents current achievements for expansion of MSCs. Issues involving culture condition modification, bioreactor systems, as well as microcarrier and scaffold platforms for optimal MSC systems are discussed. Most importantly, the gap between current MSC expansion and clinical application, as well as outbreak directions for the future are discussed. The present systemic review will bring new insights into future large-scale MSC expansion and clinical application.

Critical View on Mesenchymal Stromal Cells in Regenerative Medicine

SIGNIFICANCE

The belief in the potency of stem cells has resulted in the medical applications of numerous cell types for organ repair, often with the low adherence to methodological stringency. Such uncritical enthusiasm is mainly presented in the approaches employing so-called mesenchymal stem cells (MSC), for the treatment of numerous, unrelated conditions. However, it should be stressed that such broad clinical applications of MSC are mostly based on the belief that MSC can efficiently differentiate into multiple cell types, not only osteoblasts, chondrocytes and adipose cells. Recent Advances: Studies employing lineage tracing established more promising markers to characterize MSC identity and localization in vivo and confirmed the differences between MSC isolated from various organs. Furthermore, preclinical and clinical experiments proved that transdifferentiation of MSC is unlikely to contribute to repair of numerous tissues, including the heart. Therefore, the salvage hypotheses, like MSC fusion with cells in target organs or the paracrine mechanisms, were proposed to justify the widespread application of MSC and to explain transient, if any, effects.

CRITICAL ISSUES

The lack of standardization concerning the cells markers, their origin and particularly the absence of stringent functional characterization of MSC, leads to propagation of the worrying hype despite the lack of convincing therapeutic efficiency of MSC.

FUTURE DIRECTIONS

The adherence to rigorous methodological rules is necessary to prevent the application of procedures which can be dangerous for patients and scientific research on the medical application of stem cells. Antioxid. Redox Signal. 00, 000-000.

Supramolecular Platform Stabilizing Growth Factors

High concentrations of supplemented growth factors can cause oversaturation and adverse effects in in vitro and in vivo studies, though these supraphysiological concentrations are often required due to the low stability of growth factors. Here we demonstrate the stabilization of TGF-β1 and BMP4 using supramolecular polymers. Inspired by heparan sulfate, sulfonated peptides were presented on a supramolecular polymer to allow for noncovalent binding to growth factors in solution. After mixing with excipient molecules, both TGF-β1 and BMP4 were shown to have a prolonged half-life compared to the growth factors free in solution. Moreover, high cellular response was measured by a luciferase assay, indicating that TGF-β1 remained highly active upon binding to the supramolecular assembly. The results demonstrate that significant lower concentrations of growth factors can be used when supramolecular polymers bearing growth factor binding moieties are implemented. This approach can also be exploited in hydrogel systems to control growth factor release.

Short-Term Outcomes in Treatment of Knee Osteoarthritis With 4 Bone Marrow Concentrate Injections

Background

Preliminary research suggests that bone marrow concentrate (BMC), which contains mesenchymal stem cells and platelets, is a promising treatment for knee osteoarthritis. The aim of this study was to build on this preliminary research by reporting the short-term progress of 15 patients (20 knees) with knee osteoarthritis through 4 BMC treatments.

Methods

Patients underwent four sequential BMC treatments with mean injection times of 13.80 days after the first treatment, 21.40 days after the second treatment, and 33.50 days after the third treatment. The last follow-up was conducted a mean 86 days after the first treatment. Baseline and posttreatment outcomes of resting pain, active pain, lower functionality scale, and overall improvement percentage were compared after each treatment.

Results

Patients experienced statistically significant improvements in active pain and functionality score after the first treatment. Additionally, patients experienced a mean decrease in resting pain after the first treatment, yet outcomes were not statistically significant until after the second treatment. On average, patients experienced an 84.31% decrease in resting pain, a 61.95% decrease in active pain, and a 55.68% increase in functionality score at the final follow-up. Patients also reported a mean 67% total overall improvement at study conclusion. Outcomes at the final follow-up after the fourth treatment were statistically significant compared to outcomes at baseline, after first treatment, after second treatment, and after third treatment.

Conclusions

These results are promising, and additional research with a larger sample size and longer follow-up is needed to further examine the treatment effectiveness of multiple BMC injections for knee osteoarthritis.

Deciphering the role of substrate stiffness in enhancing the internalization efficiency of plasmid DNA in stem cells using lipid-based nanocarriers

This study investigates the role of substrate stiffness in the non-viral transfection of human adipose-derived stem cells (hASCs) with the aim to maximize the hASC expression of vascular endothelial growth factor (VEGF). The results confirm the direct effect of substrate stiffness in regulating cytoskeletal remodeling and corresponding plasmid internalization.

Polysaccharide-Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide-based drug delivery systems.

Platelet rich concentrate enhances mesenchymal stem cells capacity to repair focal cartilage injury in rabbits

BACKGROUND

It has been previously suggested that the use of regenerative promoters, which include bone marrow-derived mesenchymal stem cells (MSCs) or natural growth factors supplement such as platelet-rich concentrate (PRC) could promote cartilage regeneration. However, the notion that the concurrent use of both promoters may provide a synergistic effect that improves the repair outcome of focal cartilage injury has not been previously demonstrated. This study was thus conducted to determine whether the concomitant use of PRC could further enhance the reparative potential of MSCs encapsulated in alginate transplanted into focal cartilage injury in rabbits.

METHODS

Artifically created full thickness cartilage defects were made on the weight-bearing region of medial femoral condyles in bilateral knees of New Zealand White rabbits (N = 30). After one month, the right knee was treated with either i) PRC (n = 10), ii) MSCs (n = 10), or, iii) a combination of PRC and MSCs (PRC + MSC) (n = 10), all encapsulated in alginate. The left knee remained untreated (control). Rabbits were sacrificed at 3 and 6 months after treatment. Cartilage tissue regeneration was accessed using ICRS morphologic scoring, histologic grading by O'Driscoll scoring, immunohistochemical staining and quantitative analysis of glycosaminoglycans (GAG) per total protein content.

RESULTS

At 3 months, transplantation using PRC alone was equally effective as MSCs in inducing the repair of cartilage defects. However, PRC + MSC resulted in significantly higher ICRS and O'Driscoll scores (p < 0.05) as compared to other groups. The regenerated tissues from the PRC + MSC group also had stronger staining for Safranin-O and collagen type II. By 6 months, in addition to superior ICRS and O'Driscoll scores as well as stronger staining, glycosaminoglycan per total protein content was also significantly higher (p < 0.05) in the PRC + MSC group (3.4 ± 0.3 μg/mg) as compared to the MSC (2.6 ± 0.2 μg/mg) or PRC (2.1 ± 0.2 μg/mg) groups.

CONCLUSION

PRC enhances the reparative effects of MSC in treating focal articular cartilage injuries.

Cardiomyocyte differentiation of mesenchymal stem cells from bone marrow: new regulators and its implications

In the past years, cardiac mortality has decreased, but cardiac diseases are still responsible for millions of deaths every year worldwide. Bone-marrow mesenchymal stem cells (BMSCs) transplantation may be a promising therapeutic strategy because of its capacity to differentiate into cardiac cells. Current research indicates that chemical substances, microRNAs, and cytokines have biological functions that regulate the cardiomyocytes differentiation of BMSCs. In this review, we chiefly summarize the regulatory factors that induce BMSCs to differentiate into cardiomyocytes.