Using Human Plasma Supplemented Medium to Cultivate Human Bone Marrow–Derived Mesenchymal Stem Cell and Evaluation of Its Multiple-Lineage Potential

Epidermal growth factor signalling pathway in endochondral ossification: an evidence-based narrative review

During endochondral bone development, a complex process that leads to the formation of the majority of skeletal elements, mesenchymal cells condense, differentiating into chondrocytes and producing the foetal growth plate. Chondrocytes progressively hypertrophy, induce angiogenesis and are then gradually replaced by bone. Epidermal Growth Factor (EGF), one of many growth factors, is the prototype of the EGF-ligand family, which comprises several proteins involved in cell proliferation, migration and survival. In bone, EGF pathway signalling finely tunes the first steps of chondrogenesis by maintaining mesenchymal cells in an undifferentiated stage, and by promoting hypertrophic cartilage replacement. Moreover, EGF signalling modulates bone homeostasis by stimulating osteoblast and osteoclast proliferation, and by regulating osteoblast differentiation under specific spatial and temporal conditions. This evidence-based narrative review describes the EGF pathway in bone metabolism and endochondral bone development. This comprehensive description may be useful in light of possible clinical applications in orthopaedic practice. A deeper knowledge of the role of EGF in bone may be useful in musculoskeletal conditions which may benefit from the modulation of this signalling pathway.Key messagesThe EGF pathway is involved in bone metabolism.EGF signalling is essential in the very early stages of limb development by maintaining cells in an undifferentiated stage.EGF pathway positively regulates chondrocyte proliferation, negatively modulates hypertrophy, and favours cartilage replacement by bone.EGF and EGF-like proteins finely tune the proliferation and differentiation of bone tissue cells, and they also regulate the initial phases of endochondral ossification.

Concentrated growth factor promotes proliferation, osteogenic differentiation, and angiogenic potential of rabbit periosteum-derived cells in vitro

OBJECTIVE

The aim of this research is to investigate the effects of concentrated growth factor (CGF) on the proliferation, osteogenic differentiation, and angiogenic potential of rabbit periosteum-derived cells (PDCs) in vitro.

METHODS

PDCs were isolated from the femoral and tibial periosteum of rabbits and cultured with or without CGF membranes or CGF conditioned media. Scanning electron microscopy (SEM) was used for the structural characterization. Cell Counting Kit-8 assay was used to measure cell proliferation. Alkaline phosphatase (ALP) activity of PDCs was also measured. Immunohistochemistry was used to detect the expression of CD34. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time PCR (qPCR), and Western blot were used to evaluate the secretion and expression levels of osteogenic differentiation markers (bone morphogenetic protein-2, type I collagen, osteocalcin) and angiogenesis markers (vascular endothelial growth factor, basic fibroblast growth factor) in supernatants and PDCs at days 3, 7, 14, and 21.

RESULTS

The SEM analysis showed a dense three-dimensional fibrin network in CGF, and CGF membranes were covered by PDCs with elongated or polygonal morphological features. Compared with the control group, CGF significantly promoted the proliferation of PDCs during the experimental period (p < 0.05). Immunohistochemistry revealed that PDCs were dispersedly distributed among the CGF substrates, and CD34-positive cells were also present. Moreover, CGF significantly increased the ALP activity and upregulated the expression and secretion of osteogenic differentiation and angiogenesis markers in PDCs at days 3, 7, 14, and 21 (p < 0.05).

CONCLUSION

CGF can increase the proliferation and promote the osteogenic differentiation and angiogenic potential of PDCs in vitro. These results indicate that CGF can be used as a new therapeutic means for biotechnological and clinical applications.

Mechanisms of Zuogui Pill in Treating Osteoporosis: Perspective from Bone Marrow Mesenchymal Stem Cells

The current treatment strategies for osteoporosis (OP) involve promoting osteogenic differentiation and inhibiting adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). According to a theory of traditional Chinese medicine (TCM), the kidneys contain an “essence” that regulate bone metabolism and generate marrow. Kidney disorders are therefore considered to be a major cause of OP as per the principles of TCM, which recommends kidney-tonifying treatments for OP. The Zuogui pill (ZGP) is a classic kidney-tonifying medication that effectively improves OP symptoms. Studies have shown that ZGP can promote the osteogenic differentiation of BMSCs, providing scientific evidence for the TCM theory linking kidneys with bone metabolism. In this review, we have provided an overview of recent studies that examined the underlying mechanisms of ZGP mediated regulation of BMSC osteogenic and adipogenic differentiation.

Platelet-Poor Plasma as a Supplement for Fibroblasts Cultured in Platelet-Rich Fibrin

The aim of this study was to evaluate the proliferation and adhesion of mesenchymal cells (3T3/NIH) in Dulbecco’s Modified Eagle Medium(DMEM) supplemented with Platelet-Poor Plasma (PPP) in aPlatelet-Rich Fibrin (PRF) scaffold. Human blood was obtained and processed in a centrifuge considering the equation G=1.12xRx(RPM/1000)² to obtain PRF and PPP.Cell adhesion and maintenance analyses were performed by MTTassays in a 96 well plate withsupplemented DMEM: PPP (90:10) for 24 hours. Besides, the PRF was deposited in a 48 well plate and 10x10⁴ cells were seeded above each PRF (n=3) with 800µl of DMEM: PPP (90:10) and cultured for 7 days. Histological analysis and the immunohistochemical staining for Vimentin were performed. Results were analyzed by one-way ANOVA in Stata12®. A significant decrease (p<0.05) of cells adhesion in relationship to FBSwas observed. However, a similar ability of cell-maintenance for PPP 10% was observed (P>0.05). Fibroblasts culture for 7 days in PRF supplemented with PPP 10% was possible, showing positive staining for Vimentin. Therefore, PPP cell supplementation decreased the initial adhesion of cells but was able to maintain the proliferation of adhered cells and able to support their viability in PRF.It seems that this method has many clinical advantagessince it provides an autologous and natural scaffold with their respective supplement for cell culture by only one process, without using xenogeneic compounds. This could improve the potential of clinical translational therapies based on the use of PRF cultured cells, promoting the regenerative potential for future use in medicine and dentistry.

Recent Developments in Cellular Immunotherapy for HSCT-Associated Complications

Allogeneic hematopoietic stem cell transplantation is associated with serious complications, and improvement of the overall clinical outcome of patients with hematological malignancies is necessary. During the last decades, posttransplant donor-derived adoptive cellular immunotherapeutic strategies have been progressively developed for the treatment of graft-versus-host disease (GvHD), infectious complications, and tumor relapses. To date, the common challenge of all these cell-based approaches is their implementation for clinical application. Establishing an appropriate manufacturing process, to guarantee safe and effective therapeutics with simultaneous consideration of economic requirements is one of the most critical hurdles. In this review, we will discuss the recent scientific findings, clinical experiences, and technological advances for cell processing toward the application of mesenchymal stromal cells as a therapy for treatment of severe GvHD, virus-specific T cells for targeting life-threating infections, and of chimeric antigen receptors-engineered T cells to treat relapsed leukemia.

Human plasma and human platelet-rich plasma as a substitute for fetal calf serum during long-term cultivation of mesenchymal dental pulp stem cells

AIMS

Our aims were to isolate and cultivate mesenchymal dental pulp stem cells (DPSC) in various media enriched with human blood components, and subsequently to investigate their basic biological properties.

METHODS

DPSC were cultivated in five different media based on α MEM containing different concentrations of human plasma (HP), platelet-rich plasma (PRP), or fetal calf serum (FCS). The DPSC biological properties were examined periodically.

RESULTS

We cultivated DPSC in the various cultivation media over 15 population doublings except for the medium supplemented with 10% HP. Our results showed that DPSC cultivated in medium supplemented with 10% PRP showed the shortest average population doubling time (DT) (28.6 ± 4.6 hours), in contrast to DPSC cultivated in 10% HP which indicated the longest DT (156.2 ± 17.8 hours); hence this part of the experiment had been cancelled in the 6th passage. DPSC cultivated in media with 2% FCS+ITS (DT 47.3 ± 10.4 hours), 2% PRP (DT 40.1 ± 5.7 hours) and 2% HP (DT 49.0 ± 15.2 hours) showed almost the same proliferative activity. DPSC's viability in the 9th passage was over 90% except for the DPSC cultivated in the 10% HP media.

CONCLUSIONS

We proved that human blood components are suitable substitution for FCS in cultivation media for long-term DPSC cultivation.

Alkaline phosphatase expression/activity and multilineage differentiation potential are the differences between fibroblasts and orbital fat-derived stem cells--a study in animal serum-free culture conditions

Human orbital fat tissues are a potential source to isolate stem cells for the development of regenerative medicine therapies. For future safe clinical application of these cells, it is critical to establish animal component-free culture conditions as well as to clearly define the stem cell population characteristics differentiating them from other cell types, such as fibroblasts. Therefore, the present study aimed to compare phenotypic and functional characteristics of orbital fat-derived stem cells (OFSCs) and fibroblasts resident in the eyelid skin in donor-matched samples grown in culture medium supplemented with pooled allogeneic human serum (HS) replacing fetal bovine serum (FBS). We first investigated the proliferative effects of OFSCs on HS, and then we compared the alkaline phosphatase (AP) expression and activity, immunophenotypic profile, and in vitro multilineage differentiation potential of OFSCs side-by-side with fibroblasts. The results showed that HS enhanced OFSCs proliferation without compromising their immunophenotype, AP activity, and osteogenic, adipogenic, and chondrogenic differentiation capacities. In contrast to OFSCs, the fibroblasts did not exhibit AP expression and activity and did not have multilineage differentiation potential. The results enabled us to successfully distinguish OFSCs from fibroblasts populations, suggesting that AP expression/activity and multilineage differentiation assays can be used reliably to discriminate mesenchymal stem cells from fibroblasts. Our findings also support the feasibility of pooled allogeneic HS as a safer and more effective alternative to FBS for clinical applications.

Culture of human cell lines by a pathogen-inactivated human platelet lysate

Alternatives to the use of fetal bovine serum (FBS) have been investigated to ensure xeno-free growth condition. In this study we evaluated the efficacy of human platelet lysate (PL) as a substitute of FBS for the in vitro culture of some human cell lines. PL was obtained by pools of pathogen inactivated human donor platelet (PLT) concentrates. Human leukemia cell lines (KG-1, K562, JURKAT, HL-60) and epithelial tumor cell lines (HeLa and MCF-7) were cultured with either FBS or PL. Changes in cell proliferation, viability, morphology, surface markers and cell cycle were evaluated for each cell line. Functional characteristics were analysed by drug sensitivity test and cytotoxicity assay. Our results demonstrated that PL can support growth and expansion of all cell lines, although the cells cultured in presence of PL experienced a less massive proliferation compared to those grown with FBS. We found a comparable percentage of viable specific marker-expressing cells in both conditions, confirming lineage fidelity in all cultures. Functionality assays showed that cells in both FBS- and PL-supported cultures maintained their normal responsiveness to adriamycin and NK cell-mediated lysis. Our findings indicate that PL is a feasible serum substitute for supporting growth and propagation of haematopoietic and epithelial cell lines with many advantages from a perspective of process standardization, ethicality and product safety.

Optimization of pre-transplantation conditions to enhance the efficacy of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are considered a potential tool for cell based regenerative therapy due to their immunomodulatory property, differentiation potentials, trophic activity as well as large donor pool. Poor engraftment and short term survival of transplanted MSCs are recognized as major limitations which were linked to early cellular ageing, loss of chemokine markers during ex vivo expansion, and hyper-immunogenicity to xeno-contaminated MSCs. These problems can be minimized by ex vivo expansion of MSCs in hypoxic culture condition using well defined or xeno-free media i.e., media supplemented with growth factors, human serum or platelet lysate. In addition to ex vivo expansion in hypoxic culture condition using well defined media, this review article describes the potentials of transient adaptation of expanded MSCs in autologous serum supplemented medium prior to transplantation for long term regenerative benefits. Such transient adaptation in autologous serum supplemented medium may help to increase chemokine receptor expression and tissue specific differentiation of ex vivo expanded MSCs, thus would provide long term regenerative benefits.

Cyclin-dependent kinase 4 signaling acts as a molecular switch between syngenic differentiation and neural transdifferentiation in human mesenchymal stem cells

Multipotent mesenchymal stem/stromal cells (MSCs) are capable of differentiating into a variety of cell types from different germ layers. However, the molecular and biochemical mechanisms underlying the transdifferentiation of MSCs into specific cell types still need to be elucidated. In this study, we unexpectedly found that treatment of human adipose- and bone marrow-derived MSCs with cyclin-dependent kinase (CDK) inhibitor, in particular CDK4 inhibitor, selectively led to transdifferentiation into neural cells with a high frequency. Specifically, targeted inhibition of CDK4 expression using recombinant adenovial shRNA induced the neural transdifferentiation of human MSCs. However, the inhibition of CDK4 activity attenuated the syngenic differentiation of human adipose-derived MSCs. Importantly, the forced regulation of CDK4 activity showed reciprocal reversibility between neural differentiation and dedifferentiation of human MSCs. Together, these results provide novel molecular evidence underlying the neural transdifferentiation of human MSCs; in addition, CDK4 signaling appears to act as a molecular switch from syngenic differentiation to neural transdifferentiation of human MSCs.

An Effective and Safe Supplement for Stem Cells Expansion Ex Vivo: Cord Blood Serum

Mesenchymal stem cells (MSCs) are potential and optimal stem cells in clinical cell therapy, and fetal bovine serum (FBS) is widely used for expansion of MSCs, despite the risks of infectious disease transmission and immunological reaction of the xenogenic origin. This study was designed to compare human four blood group cord blood serum (CBS) with FBS in culturing human placenta-derived mesenchymal stem cells (hPDMSCs), which were derived from four blood group donors. The expansion medium included: 10% FBS, 10% A-CBS, 10% B-CBS, 10% O-CBS, and 10% AB-CBS. Cumulative population doubling, generation time, fold expansion rates and differentiation capacity, cell cycle, and immunophenotype were also assessed. The results showed that fold expansion rate and cumulative population doubling of hPDMSCs significantly increased during long-term MSC expansion in CBS medium, but the generation time decreased compared with FBS. CBS might be an effective supplement for stem cells expand rapidly ex vivo. Cell cycle and differentiation assays showed that most of the hPDMSCs expanding in the presence of CBS were in stationary phase, which was the characteristic of stem cells, and they retained their ability to differentiate into chondrogenic and endothelial cells. By comparing these four blood groups of CBS, we found that there was no significant difference among different blood groups in culturing hPDMSCs, which were isolated from different blood group donors. So CBS may be an optimal replacement to avoid the risks of FBS application in expansion of stem cell for clinical cell therapy and tissue engineering.

Expansion of Mesenchymal Stem/Stromal cells under xenogenic-free culture conditions

Mesenchymal Stem/Stromal cells (MSCs) are increasingly applied in cell-based regenerative medicine. To yield clinically relevant cell doses, ex vivo expansion of MSCs is required to be compliant with good manufacturing practice (GMP) guidelines. A lack of standardization and harmonization seems to hamper rapid progress in the translational phase. Most protocols still use fetal bovine serum (FBS) to expand MSCs. However, the high lot-to-lot variability, risk of contamination and immunization call for xenogenic-free culture conditions. Chemically defined media are the ultimate achievement in terms of standardization. These media, however, need to maintain all key cellular and therapy-relevant features of MSCs. Because of the numerous constituents of FBS, the development of such chemically defined media with an optimal composition of the few essential factors is only beginning. Meanwhile, various human blood-derived components are under investigation, including human plasma, human serum, human umbilical cord blood serum and human platelet derivatives such as platelet lysate.

Mesenchymal stem cell therapy in the treatment of acute and chronic graft versus host disease

Mesenchymal stem cells (MSC) are a cellular component of the supportive microenvironment (stroma) found in the bone marrow, umbilical cord, placenta, and adipose tissues. In addition to providing cellular and extracellular cues to support the proliferation and differentiation of cells that comprise functional tissues, MSC also contribute to tissue repair and have immunomodulatory properties. Their ability to modulate immunologic reactions while themselves not provoking immunologic responses from alloreactive T-lymphocytes and/or other effector cells, make MSC a potentially ideal therapeutic agent with which to treat graft versus host disease (GvHD) following hematopoietic transplantation. Despite in vitro experiments confirming that MSC suppress mixed lymphocyte reactions (MLR) and in vivo evidence from mouse models that show evidence that MSC can ameliorate GvHD, clinical trials to date using MSC to treat GvHD have shown mixed results. Whether this is a consequence of suboptimal timing and dose of administered MSC remains to be clarified. It is clear that immunomodulatory potential of MSC as a cellular therapy for GvHD remains to be realized in the clinic.

Nonsenescent Hsp27-Upregulated MSCs Implantation Promotes Neuroplasticity in Stroke Model

Cellular senescence induces changes in cellular physiology, morphology, proliferative capacity, and gene expression. Stem cell senescence might be one of the major issues of limited efficacy of stem cell transplantation. In this study, we demonstrated that implantation of human umbilical cord mesenchymal stem cells (hUCMSCs) cultured in human umbilical cord serum (hUCS) significantly enhanced neuroplasticity and angiogenesis in stroke and ischemic limb models. Immunophenotypic analysis indicated that hUCMSCs cultured in hUCS had more small and rapidly self-renewing cells than those expanded in FCS. The main cause of greater senescence in FCS-cultured cells was increased generation of reactive oxygen species (ROS). Proteome profiling showed significantly more senescence-associated vimentin in FCS-cultured hUCMSCs than in hUCS-cultured hUCMSCs. In contrast, there was significant upregulation of heat shock protein 27 (Hsp27) in the hUCS-cultured hUCMSCs. By gene targeting, we found that overexpression of Hsp27 may downregulate vimentin expression through inhibition of the nuclear translocation of p65 (NF-κB signaling). Thus, an interaction between Hsp27 and vimentin may modulate the degree of senescence in hUCS- and FCS-cultured hUCMSCs. In summary, hUCMSCs exhibiting senescence are detrimental to cell engraftment and differentiation in animal models via activation of NF-κB pathway. Human stem cells incubated in hUCS might reduce the senescent process through upregulation of Hsp27 to increase implantation efficiency.

Adipogenesis in nonadherent and adherent bone marrow stem cells grown in fibrin gel and in the presence of adult plasma

Bone marrow-derived mesenchymal stem cells (i.e., adherent cells) are known to differentiate into fat tissue in the presence of adipogenic supplements in cultures. Induction of adipogenesis has not been investigated within the nonadherent cell fraction that includes predominantly hematopoietic cells. In the present study, murine nonadherent bone marrow-derived stem cells (96% CD45+ cells) were seeded and then grown in fibrin gel to form cell clusters in which most cells were positive to DiI-acetylated low-density lipoprotein uptake. Amongst different culture media supplemented either in fetal bovine serum, horse serum, murine plasma, human plasma or adipogenic supplements, a subpopulation of nonadherent stem cells within clusters differentiated into adipocytes, specifically in the presence of adult syngeneic plasma. This was confirmed by the observation and quantification of oil red O-positive cells, the measurement of glycerol-3-phosphate dehydrogenase activity and peroxisome proliferator-activated receptor-gamma mRNA expression. Similarly, adipogenesis was also observed in the presence of murine plasma with adherent mesenchymal stem cells and 3T3-L1 preadipocytes which were grown either in monolayer plastic cultures or in fibrin gel. Thus, it is possible that nonadherent cells, once in a 3-dimensional environment, can further differentiate towards adipogenesis.

Mesenchymal stem cell tissue engineering: techniques for isolation, expansion and application

Mesenchymal stem cells (MSCs) are undifferentiated multipotent cells which reside in various human tissues and have the potential to differentiate into osteoblasts, chondrocytes, adipocytes, fibroblasts and other tissues of mesenchymal origin. In the human body they could be regarded as readily available reservoirs of reparative cells capable to mobilize, proliferate and differentiate to the appropriate cell type in response to certain signals. These properties have triggered a variety of MSC-based therapies for pathologies including nonunions, osteogenesis imperfecta, cartilage damage and myocardial infarction. The outcome of these approaches is influenced by the methodologies and materials used during the cycle from the isolation of MSCs to their re-implantation. This review article focuses on the pathways that are followed from the isolation of MSCs, expansion and implantation.

Concise Review: No Breakthroughs for Human Mesenchymal and Embryonic Stem Cell Culture: Conditioned Medium, Feeder Layer, or Feeder-Free; Medium with Fetal Calf Serum, Human Serum, or Enriched Plasma; Serum-Free, Serum Replacement Nonconditioned Medium, or Ad Hoc Formula? All That Glitters Is Not Gold!

The choice of an optimal strategy of stem cell culture is at the moment an impossible task, and the elaboration of a culture medium adapted to the production of embryonic and adult mesenchymal stem cells for the clinical application of cell therapy remains a crucial matter. To make an informed choice, it is crucial to not underestimate the theoretical health risk of using xenogenic compounds, to limit the immunological reactions once stem cells are transplanted, to not overestimate the controversial results obtained with human serum, plasma, and blood derivatives, as well as to carefully examine the pros and cons of serum-free and ad hoc formulation strategies; besides that, to also maintain multipotentiality, self-renewal, and transplantability. The extent to which we are able to achieve effective cell therapies will depend on assimilating a rapidly developing base of scientific knowledge with the practical considerations of design, delivery, and host response. Although clinical studies have already started, many questions remain unsolved, and concomitantly even more evidence on suitable and safe off-the-shelf products (mainly xeno-free) for embryonic and mesenchymal stem cells is cropping up, even though there should be no rush to enter the clinical stage while the underlying basic research is still not so solid; this solely will lead to high-quality translational research, without making blunders stemming from the assumption that all that glitters is not gold. Disclosure of potential conflicts of interest is found at the end of this article.