Human umbilical cord blood serum can replace fetal bovine serum in the culture of mesenchymal stem cells

Characterization of mesenchymal stem cells isolated from Wharton’s jelly of the human umbilical cord

Background

Isolation of post-partum umbilical cord Wharton’s jelly stem cells has gained attention as an alternative source of the bone marrow. Because easy isolation, lack of ethical concerns, and the presence of both embryonic and adult stem cells have made them a valuable source for use in therapeutic applications and regenerative medicine. The study utilized a modified protocol using in-house human pooled cord blood serum for isolation and expansion of the mesenchymal stem cells obtained from the human umbilical cord Wharton’s jelly. Cell proliferation and population doubling time and tri-lineage differentiation were assessed, and the expressions of mesenchymal cell surface markers CD44, CD90, CD105, and CD34 were assessed by flow cytometry and RT-PCR. The genetic stability of the isolated cells was assessed by chromosomal karyotype.

Results

The isolated cells displayed fibroblastic-like morphology and tri-lineage differentiation into adipocyte, chondrocyte, and osteocyte. The isolated cells maintained the proliferative competence with a doubling time ranged from 38 to 42h and corresponded well with the standard positive and negative molecular markers (CD44+, CD90+, CD 105+, and CD34−). Cell senescence occurred at the later passage of the cells (P15) affecting, about 25% of the population. Metaphases spread of the cells showed normal diploid karyotypes, with typical chromosomal plates indicating genetic stability of the isolated cells.

Conclusion

The primary cultures exhibited success in isolating the umbilical cord Wharton’s jelly mesenchymal stem cells, which maintained their tri-lineage differentiation potential, phenotypes and karyotype characteristics on further passage and expansion.

Preparation and growth factor characterization of cord blood-derived plasma, serum, growth factor-rich plasma and induced serum

BACKGROUND

In recent years, there has been a significant decline in the demand for cord blood units (CBUs). This trend has led to cord blood banks (CBBs) exploring complementary uses of CBUs in order to exploit the full potential of this unique, valuable, and readily available product. The aim of this study was to establish standardized protocols for the preparation of four cord blood (CB) derivatives: plasma (CB-P), serum (CB-S), induced-serum (CB-IS) and growth factor-rich plasma (GFRP); to measure their respective growth-factor content and their potential as cell culture supplements, and finally, to identify the characteristics of each derivative beyond their growth-factor composition, in the context of optimizing CBBs resources.

STUDY DESIGN AND METHOD

To this end, CB plasma and serum were prepared and their concentrations for ten growth factors (TGF-β1, TGF-β2, TGF-β3, EGF, HGF, PDGF-BB, VEGF-A, VEGF-D, IGF-I, IGF-II) were determined using a multiplex bead array, and compared to adult plasma and serum. Protocols for the preparation of CB-IS and GFRP with reverse anticoagulation using CaCl₂·2H₂O were also established, and all four derivatives were compared for their EGF and TGF-β1 content by enzyme-linked immunosorbent assay (ELISA), and also for their cell culture supplement capacity.

RESULTS

CB plasma was shown to be richer than adult plasma for TGF-β2 and TGF-β3, with a lower concentration of IGF-I and IGF-II. CB serum was shown to be richer than adult serum for TGF-β2, TGF-β3, EGF, HGF, PDGF-BB, and VEGF-A and D, and poorer in IGF-I and II. The measure of EGF and TGF-β1 concentrations has shown that CB serum is the most concentrated (1874 pg/ml and 41 094 pg/ml) of the CB derivatives, followed by induced-serum (405 pg/ml and 16 735 pg/ml), growth factor-rich plasma (131 and 7947 pg/ml) and plasma (8 and 2845 pg/ml). All four CB derivatives were shown to be superior to FBS in sustaining cell growth at low doses.

CONCLUSION

Our study shows that four CB derivatives can be easily prepared and pooled to provide significant volume of products that vary in their growth factor composition. A cord blood bank interested in introducing such manufacturing will need to evaluate the financial and processing characteristics of each derivative. The use of standardized manufacturing protocols such as the ones we suggest could help research initiatives exploring the potential therapeutic uses of such rich and high-quality starting material.

A critical appraisal of humanized alternatives to fetal bovine serum for clinical applications of umbilical cord derived mesenchymal stromal cells

OBJECTIVE

The study is aimed to verify the possibility of using humanized alternatives to fetal bovine serum (FBS) such as umbilical cord blood plasma (CBP) and AB⁺ plasma to support the long-term growth of mesenchymal stromal cells (MSCs) derived from the umbilical cord. We hypothesized that umbilical CBP would be a potential substitute to FBS, especially for small scale autologous clinical transplantations.

METHODS

The MSCs were cultured for six consecutive passages to evaluate xeno-free media's ability to support long-term growth. Cell proliferation rates, colony-forming-unit (CFU) efficiency and population doublings of expanded MSCs, were investigated. Ex vivo expanded MSCs were further characterized using flow cytometry and quantitative PCR. The impact of cryopreservation and composition of cryomedium on phenotype, viability of MSC was also assessed.

RESULTS

Our results on cell proliferation, colony-forming unit efficiency suggested that the expansion of the cells was successfully carried out in media supplemented with humanized alternatives. MSCs showed lower CFU counts in FBS (~ 25) than humanized alternatives (~ 35). The gene expression analysis revealed that transcripts showed significant differential expression by two to three folds in the FBS group compared with MSCs grown in medium with humanized alternatives (p < 0.05). In addition, MSCs grown in a medium with FBS had more osteogenic activity, a signature of unwanted differentiation. The majority of ex vivo expanded MSCs at early and late passages expressed CD44⁺, CD73⁺, CD105⁺, CD90⁺, and CD166⁺ in all the experimental groups tested (~ 90%). In contrast to the other MSC surface markers, expression levels of STRO-1⁺ (~ 21-10%) and TNAP⁺ (~ 29-11%) decreased with the increase in passage number for MSCs cultured in a FBS-supplemented medium (p < 0.05).

CONCLUSION

Our results established that CBP supported culture of umbilical cord tissue-derived MSCs and is a safer Xeno free replacement to FBS. The use of CBP also enables the storage of umbilical cord tissue derived MSCs in patient-specific conditions to minimize adverse events if cells are delivered directly to the patient.

Regenerative Therapy Using Umbilical Cord Serum

Regenerative medicine is a branch of medicine that incorporates tissue-engineering, biomaterials, and cell therapy approaches to replace or repair damaged cells and tissues. Umbilical cord serum (UCS) is an important liquid component of cord blood, which has a reliable source of innumerable growth factors and biologically active molecules. Usually, serum can be prepared from different sources of blood. In therapeutic application, cord serum can be prepared and used in the form of eye drops for the treatment of severe dry eye diseases, ocular burns, glaucoma, persistent corneal epithelial defects and neurotrophic keratitis. In addition, cord serum combined with synthetic bio scaffold materials is used to regenerate different types of tissues including tympanic membrane regeneration, bone regeneration and nerve regeneration. Absence of animal origin viruses and bacteria, lack of xenoproteins and cost-effective features make cord serum a feasible choice as replacement of fetal bovine serum in cell culture techniques. Thus, this review emphasizes the role of cord serum in regenerative therapy and clinical uses.

Treatment with human umbilical cord blood serum in a gentamicin-induced nephrotoxicity model in rats

Sold under the brand name of Garamycin, gentamicin (GM) is an antibiotic in the category of aminoglycoside, that although does have many antibacterial properties, owing to several side effects, its consumption is confined. The current study is aimed at gauging the protective influences of human umbilical cord blood serum (hUCBS) on nephrotoxicity which is induced by GM. In this regard, in the present experimental design, twenty-eight male Wistar rats with the weights of 220 ± 20 g were categorized randomly into 4 groups of seven. The groups included GM (100 mg/kg), control as well as hUCBS at doses of one and two percent together with GM (100 mg/kg) for ten days in an intraperitoneal manner. Blood sampling was collected from the heart directly 24 h after the final injection for obtaining blood serum; the parameters of C-reactive protein (CRP), total oxidant status (TOS), interleukin (IL)-6, lactate dehydrogenase (LDH), total antioxidant capacity (TAC), creatinine (Cr), blood urea nitrogen (BUN), blood serum glutathione (GSH) were gauged in blood serum samples to evaluate renal function. Moreover, for histology, an examination of kidney tissue was performed. In comparison to those of the GM group, in the treatment group, hUCBS significantly decreased the levels of BUN, Cr, LDH, TOS, IL-6, and the CRP levels, and significantly increased the TAC and GSH levels. It was revealed that the treatment of the animals with hUCBS culminates in the reduction of GM' toxic impacts on the kidney.

Influences of Xeno-Free Media on Mesenchymal Stem Cell Expansion for Clinical Application

Mesenchymal stem/stromal cells (MSCs) are multipotent somatic stem/progenitor cells that can be isolated from various tissues and have attracted increasing attention from the scientific community. This is due to MSCs showing great potential for incurable disease treatment, and most applications of MSCs involve tissue degeneration and treatment of immune- and inflammation-mediated diseases. Conventional MSC cultures contain fetal bovine serum (FBS), which is a common supplement for cell development but is also a risk factor for exposure to animal-derived pathogens. To avoid the risks resulting from the xenogeneic origin and animal-derived pathogens of FBS, xeno-free media have been developed and commercialized to satisfy MSC expansion demands for human clinical applications. This review summarized and provided an overview of xeno-free media that are currently used for MSC expansion. Additionally, we discussed the influences of different xeno-free media on MSC biology with particular regard to cell morphology, surface marker expression, proliferation, differentiation and immunomodulation. The xeno-free media can be serum-free and xeno-free media or media supplemented with some human-originating substances, such as human serum, human platelet lysates, human umbilical cord serum/plasma, or human plasma-derived supplements for cell culture medium. These media have capacity to maintain a spindle-shaped morphology, the expression of typical surface markers, and the capacity of multipotent differentiation and immunomodulation of MSCs. Xeno-free media showed potential for safe use for human clinical treatment. However, the influences of these xeno-free media on MSCs are various and any xeno-free medium should be examined prior to being used for MSC cultures.

Cord blood serum harvesting by hydroxyethyl starch: a fetal bovine serum alternative in expansion of umbilical cord-derived mesenchymal stem cells

As a widely used cell culture supplement, fetal bovine serum (FBS) harbor high content of growth, proliferation, and adhesion factors. However, high cost, bio-safety, possible xenogeneic agent transmission, finite accessible, and ethical controversy are major obstacles that discourage the use of this additive. Accordingly, novel alternatives have been proposed with various pros and cons. Still, caution should be taken in choosing suitable substitute given that the alteration in the main aspects of cultured cells can be biased the consequences of clinical applications. Herein, the authors evaluated the impact of cord blood serum harvesting by hydroxyethyl starch (CBS-HES), as an enriched source of growth factors, on the basic mesenchymal stem cells (MSCs) characteristics. In the present experiment, umbilical cord-derived MSCs were isolated and continuously nourished with Dulbecco's Modified Eagle Medium containing either 10, 15, and 20% CBS-HES or FBSs to compare their morphology, immunophenotype, growth and proliferation rate, death rate, cell cycle, and gene expression profiles. Although all enriched media supported the expansion of MSCs with comparable morphology, cell surface markers, death rate, c-MYC and p16 expression, and growth rate, CBS-HES treated cells significantly (P < 0.05) expressed more hTERT gene in a concentration-dependent manner. Yet no significant shift was observed in the cell cycle of cultured cells using the same concentrations of additives, a finding which further confirmed by Ki-67 immunostaining. CBS-HES as an available and affordable additive, seems to be an optimal, relatively safe, and promising FBS alternative for cultivation, propagation, and subsequent clinical applications of MSCs.

Blood Serum Stimulates p38-Mediated Proliferation and Changes in Global Gene Expression of Adult Human Cardiac Stem Cells

During aging, senescent cells accumulate in various tissues accompanied by decreased regenerative capacities of quiescent stem cells, resulting in deteriorated organ function and overall degeneration. In this regard, the adult human heart with a generally low regenerative potential is of extreme interest as a target for rejuvenating strategies with blood borne factors that might be able to activate endogenous stem cell populations. Here, we investigated for the first time the effects of human blood plasma and serum on adult human cardiac stem cells (hCSCs) and showed significantly increased proliferation capacities and metabolism accompanied by a significant decrease of senescent cells, demonstrating a beneficial serum-mediated effect that seemed to be independent of age and sex. However, RNA-seq analysis of serum-treated hCSCs revealed profound effects on gene expression depending on the age and sex of the plasma donor. We further successfully identified key pathways that are affected by serum treatment with p38-MAPK playing a regulatory role in protection from senescence and in the promotion of proliferation in a serum-dependent manner. Inhibition of p38-MAPK resulted in a decline of these serum-mediated beneficial effects on hCSCs in terms of decreased proliferation and accelerated senescence. In summary, we provide new insights in the regulatory networks behind serum-mediated protective effects on adult human cardiac stem cells.

Isolation of umbilical cord mesenchymal stem cells using human blood derivatives accompanied with explant method

Background

Mesenchymal stem cells (MSCs) are multipotent cells which can be isolated from many sources including umbilical cord. Isolation protocols are depended on either explant or enzymatic methods. Although fetal bovine serum (FBS) is used as a supplement in isolation and expansion of MSCs, human blood derivatives such as cord blood serum (CBS) and platelet lysate (PL) are attractive substitutes of FBS which overcome impediments of using FBS in clinical setups.

Methods

Here we compared the effect of using CBS, PL and FBS supplemented media in isolation of umbilical cord tissue derived MSCs by using explant method. To do that we cultured umbilical cord tissue explant in either CBS or PL or FBS supplemented media. Isolated cells were quantified, their morphology was assessed and Cells in passage 3 were characterized based on their immunophenotyping and their potential for differentiation into adipocytes and osteocytes. Moreover, proliferation of cells was assessed by crystal violet staining.

Results

All the three media succeeded to isolate MSCs and maintain their stemness characteristics. However, the highest number of isolated cells were obtained using CBS, ~10-fold more than FBS, while the number of isolated cells obtained using PL was ~2-fold more than FBS. Moreover, crystal violet showed that both PL and CBS promote proliferation of MSCs more than FBS.

Conclusions

Our data suggest that, although all supplements maintain stemness characteristics of MSCs when used to isolate those cells by explant method, using human blood derived supplements is more effective than FBS. In the same context CBS is more effective than PL.

Autologous plasma rich in growth factors technology for isolation and ex vivo expansion of human dental pulp stem cells for clinical translation

AIM

This study investigated the use of the autologous technology of plasma rich in growth factors (PRGF) as a human-based substitute to fetal bovine serum (FBS) in the culture of human dental pulp stem cells.

MATERIALS & METHODS

Stem cell characterization was performed. Analysis of isolation, proliferation, migration, trilineage differentiation, senescence and cryopreservation were compared between FBS and PRGF.

RESULTS

Human dental pulp stem cell cultures isolated and maintained with PRGF showed a significantly higher number of cells per explant than FBS cultures. Cell proliferation, migration, osteogenic mineralization and adipogenic differentiation were found to be significantly higher in PRGF than FBS.

CONCLUSION

The autologous PRGF technology could be a suitable and safer substitute for FBS as a culture medium supplement for clinical translation of cell therapy.

Therapeutic Potential of Plasma Proteins Derived from Umbilical Cord Blood for Acute Liver Failure

There are very limited clinically viable treatment options for acute liver failure, a life-threatening condition that rapidly progresses to loss of liver function. In this study, we aim to evaluate the therapeutic potential of UCBP for acute liver failure induced in a rat model by D-galactosamine (GalN). F344 rats were randomly divided into two groups (control and UCBP-treated) after GalN injection. The therapeutic effects of UCBP were evaluated based on survival rate, H&E staining, TUNEL, PCNA staining, and in vivo BrdU labeling. Hepatocyte proliferation and the therapeutic mechanisms of UCBP were examined with BrdU and Western blot assay in vitro. The survival rate in the UCBP-treated group was found to be increased compared to the control group (85 vs 55%, P = 0.029). UCBP treatment significantly decreased apoptosis and increased cell proliferation. These effects may be secondary to specific bioactive molecules in UCBP. In vitro experiments revealed that adiponectin is one of the key biologically active components of UCBP in facilitating this result and promoting hepatocyte proliferation. Furthermore, this effect is mediated by p38/ERK mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, this uncomplicated and clinically accessible approach may serve as effective bridge therapy for acute liver failure.

Human umbilical cord blood plasma as an alternative to animal sera for mesenchymal stromal cells in vitro expansion - A multicomponent metabolomic analysis

Mesenchymal Stromal cells (MSCs) have a potential role in cell-based therapies. Foetal bovine serum (FBS) is used to supplement the basal cell culture medium but presents several disadvantages and risks. Other alternatives have been studied, including human umbilical cord blood plasma (hUCBP), aiming at the development of xeno-free culturing protocols. A comparative characterization of multicomponent metabolic composition of hUCBP and commercial FBS based on Nuclear Magnetic Resonance (NMR) spectroscopy and multivariate statistical analysis was performed. The analysis of ¹H-NMR spectra revealed both similarities and differences between the two proposed supplements. Similar metabolites (amino acids, glucose, lipids and nucleotides) were found in the hUCBP and FBS NMR spectra. The results show that the major difference between the metabolic profiles of the two proposed supplements are due to the significantly higher levels of glucose and lower levels of lactate, glutamate, alanine and branched chain amino acids in hUCBP. Similar or slightly different levels of important proteinogenic amino acids, as well as of nucleotides, lipids were found in the hUCBP and FBS. In order to validate it’s suitability for cell culture, umbilical cord-MSCs (UC-MSCs) and dental pulp stem cells (DPSCs) were expanded using hUCBP. In both hMSCs, in vitro culture with hUCBP supplementation presented similar to improved metabolic performances when compared to FBS. The two cell types tested expressed different optimum hUCBP percentage content. For DPSCs, the optimum hUCBP content was 6% and for UC-MSCs, 4%. Cultured hMSCs displayed no changes in senescence indicators, as well as maintained characteristic surface marker’s expression. FBS substitution was associated with an increase in early apoptosis events, in a dose dependent manner, as well as to slight up- and down-regulation of targeted gene’s expression. Tri-lineage differentiation capacity was also influenced by the substitution of FBS by hUCBP.

A Simple Method to Isolate and Expand Human Umbilical Cord Derived Mesenchymal Stem Cells: Using Explant Method and Umbilical Cord Blood Serum

Background and Objectives

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated from umbilical cords and are therapeutically used because of their ability to differentiate into various types of cells, in addition to their immunosuppressive and anti-inflammatory properties. Fetal bovine serum (FBS), considered as the standard additive when isolating and culturing MSCs, has a major limitation related to its animal origin. Here, we employed a simple and economically efficient protocol to isolate MSCs from human umbilical cord tissues without using digestive enzymes and replacing FBS with umbilical cord blood serum (CBS).

Methods and Results

MSCs were isolated by culturing umbilical cord pieces in CBS or FBS supplemented media. Expansion and proliferation kinetics of cells isolated by explant method in the presence of either FBS or CBS were measured, with morphology and multi-differentiation potential of expanded cells characterized by flow cytometry, RT-PCR, and immunofluorescence. MSCs maintained morphology, immunophenotyping, multi-differentiation potential, and self-renewal ability, with better proliferation rates for cells cultured in CBS compared to FBS supplement media.

Conclusions

We here present a simple, reliable and efficient method to isolate MSCs from umbilical cord tissues, where cells maintained proliferation, differentiation potential and immunophenotyping properties and could be efficiently expanded for clinical applications.

Culture Medium Supplements Derived from Human Platelet and Plasma: Cell Commitment and Proliferation Support

Present cell culture medium supplements, in most cases based on animal sera, are not fully satisfactory especially for the in vitro expansion of cells intended for human cell therapy. This paper refers to (i) an heparin-free human platelet lysate (PL) devoid of serum or plasma components (v-PL) and (ii) an heparin-free human serum derived from plasma devoid of PL components (Pl-s) and to their use as single components or in combination in primary or cell line cultures. Human mesenchymal stem cells (MSC) primary cultures were obtained from adipose tissue, bone marrow, and umbilical cord. Human chondrocytes were obtained from articular cartilage biopsies. In general, MSC expanded in the presence of Pl-s alone showed a low or no proliferation in comparison to cells grown with the combination of Pl-s and v-PL. Confluent, growth-arrested cells, either human MSC or human articular chondrocytes, treated with v-PL resumed proliferation, whereas control cultures, not supplemented with v-PL, remained quiescent and did not proliferate. Interestingly, signal transduction pathways distinctive of proliferation were activated also in cells treated with v-PL in the absence of serum, when cell proliferation did not occur, indicating that v-PL could induce the cell re-entry in the cell cycle (cell commitment), but the presence of serum proteins was an absolute requirement for cell proliferation to happen. Indeed, Pl-s alone supported cell growth in constitutively activated cell lines (U-937, HeLa, HaCaT, and V-79) regardless of the co-presence of v-PL. Plasma- and plasma-derived serum were equally able to sustain cell proliferation although, for cells cultured in adhesion, the Pl-s was more efficient than the plasma from which it was derived. In conclusion, the cells expanded in the presence of the new additives maintained their differentiation potential and did not show alterations in their karyotype.

Comparative analyses of industrial-scale human platelet lysate preparations

BACKGROUND

Efforts are underway to eliminate fetal bovine serum from mammalian cell cultures for clinical use. An emerging, viable replacement option for fetal bovine serum is human platelet lysate (PL) as either a plasma-based or serum-based product.

STUDY DESIGN AND METHODS

Nine industrial-scale, serum-based PL manufacturing runs (i.e., lots) were performed, consisting of an average ± standard deviation volume of 24.6 ± 2.2 liters of pooled, platelet-rich plasma units that were obtained from apheresis donors. Manufactured lots were compared by evaluating various biochemical and functional test results. Comprehensive cytokine profiles of PL lots and product stability tests were performed. Global gene expression profiles of mesenchymal stromal cells (MSCs) cultured with plasma-based or serum-based PL were compared to MSCs cultured with fetal bovine serum.

RESULTS

Electrolyte and protein levels were relatively consistent among all serum-based PL lots, with only slight variations in glucose and calcium levels. All nine lots were as good as or better than fetal bovine serum in expanding MSCs. Serum-based PL stored at -80°C remained stable over 2 years. Quantitative cytokine arrays showed similarities as well as dissimilarities in the proteins present in serum-based PL. Greater differences in MSC gene expression profiles were attributable to the starting cell source rather than with the use of either PL or fetal bovine serum as a culture supplement.

CONCLUSION

Using a large-scale, standardized method, lot-to-lot variations were noted for industrial-scale preparations of serum-based PL products. However, all lots performed as well as or better than fetal bovine serum in supporting MSC growth. Together, these data indicate that off-the-shelf PL is a feasible substitute for fetal bovine serum in MSC cultures.

Remodeling the Human Adult Stem Cell Niche for Regenerative Medicine Applications

The interactions between stem cells and their surrounding microenvironment are pivotal to determine tissue homeostasis and stem cell renewal or differentiation and regeneration in vivo. Ever since they were postulated in 1978, stem cell niches have been identified and characterized in many germline and adult tissues. Comprehensive studies over the last decades helped to clarify the critical components of stem cell niches that include cellular, extracellular, biochemical, molecular, and physical regulators. This knowledge has direct impact on their inherent regenerative potential. Clinical applications demand readily available cell sources that, under controlled conditions, provide a specific therapeutic function. Thus, translational medicine aims at optimizing in vitro or in vivo the various components and complex architecture of the niche to exploit its therapeutic potential. Accordingly, the objective is to recreate the natural niche microenvironment during cell therapy process development and closely comply with the requests of regulatory authorities. In this paper, we review the most recent advances of translational medicine approaches that target the adult stem cell natural niche microenvironment for regenerative medicine applications.

Re-using blood products as an alternative supplement in the optimisation of clinical-grade adipose-derived mesenchymal stem cell culture

Objectives

Adipose-derived mesenchymal stem cells (ADMSCs) are a promising strategy for orthopaedic applications, particularly in bone repair. Ex vivo expansion of ADMSCs is required to obtain sufficient cell numbers. Xenogenic supplements should be avoided in order to minimise the risk of infections and immunological reactions. Human platelet lysate and human plasma may be an excellent material source for ADMSC expansion. In the present study, use of blood products after their recommended transfusion date to prepare human platelet lysate (HPL) and human plasma (Hplasma) was evaluated for in vitro culture expansion and osteogenesis of ADMSCs.

Methods

Human ADMSCs were cultured in medium supplemented with HPL, Hplasma and a combination of HPL and Hplasma (HPL+Hplasma). Characteristics of these ADMSCs, including osteogenesis, were evaluated in comparison with those cultured in fetal bovine serum (FBS).

Results

HPL and HPL+Hplasma had a significantly greater growth-promoting effect than FBS, while Hplasma exhibited a similar growth-promoting effect to that of FBS. ADMSCs cultured in HPL and/or Hplasma generated more colony-forming unit fibroblasts (CFU-F) than those cultured in FBS. After long-term culture, ADMSCs cultured in HPL and/or Hplasma showed reduced cellular senescence, retained typical cell phenotypes, and retained differentiation capacities into osteogenic and adipogenic lineages.

Conclusion

HPL and Hplasma prepared from blood products after their recommended transfusion date can be used as an alternative and effective source for large-scale ex vivo expansion of ADMSCs.

Cite this article: J. Phetfong, T. Tawonsawatruk, K. Seenprachawong, A. Srisarin, C. Isarankura-Na-Ayudhya, A. Supokawej. Re-using blood products as an alternative supplement in the optimisation of clinical-grade adipose-derived mesenchymal stem cell culture. Bone Joint Res 2017;6:414–422. DOI: 10.1302/2046-3758.67.BJR-2016-0342.R1.

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

Mesenchymal stem cell (MSC) research progressively moves towards clinical phases. Accordingly, a wide range of different procedures were presented in the literature for MSC isolation from human tissues; however, there is not yet any close focus on the details to offer precise information for best method selection. Choosing a proper isolation method is a critical step in obtaining cells with optimal quality and yield in companion with clinical and economical considerations. In this concern, current review widely discusses advantages of omitting proteolysis step in isolation process and presence of tissue pieces in primary culture of MSCs, including removal of lytic stress on cells, reduction of in vivo to in vitro transition stress for migrated/isolated cells, reduction of price, processing time and labour, removal of viral contamination risk, and addition of supporting functions of extracellular matrix and released growth factors from tissue explant. In next sections, it provides an overall report of technical highlights and molecular events of explant culture method for isolation of MSCs from human tissues including adipose tissue, bone marrow, dental pulp, hair follicle, cornea, umbilical cord and placenta. Focusing on informative collection of molecular and methodological data about explant methods can make it easy for researchers to choose an optimal method for their experiments/clinical studies and also stimulate them to investigate and optimize more efficient procedures according to clinical and economical benefits.

The use of human umbilical cord blood serum is beneficial for the continuous production of hepatitis C virus

In this study we investigated if human umbilical cord blood serum (CBS) is a suitable replacement for foetal bovine serum (FBS) in cultures of human hepatoma cell line Huh7.5, particularly regarding its capacity to maintain high growth rates, differentiation status and its ability to support robust hepatitis C virus (HCV) infection. Generally, CBS-cultured Huh7.5 cells remained comparable to FBS-cultured cells, and proliferated equally well. Albumin secretion, a hepatocyte differentiation marker, had increased 8x in CBS; however, most other hepatocyte markers we tested had not changed. Surprisingly, CBS-cultured cells were able to sustain very high levels of HCV production, and HCV infection in CBS-cultured cells did not induce cell lysis, which is typically seen in HCV-infected cells cultured in FBS. We discuss some of the differences between CBS, adult human serum and FBS that may explain the differences observed.

Successful derivation of xeno-free mesenchymal stem cell lines from endometrium of infertile women

Transplantation of mesenchymal stem cells (MSC) can effectively repair endometrial deficiencies, including infertile patients with a problem of inadequate endometrium thickness. Although, MSC derived from different organ sources have a similarity of MSC specific characteristics, endometrial stem cells (EMSC) are temporally regulated throughout the menstrual cycle in a micro-environmental niche found only in endometrial tissue. Given the micro-environment niche, developing treatments for endometrial disorders with EMSC should be a top priority. To provide EMSC that afford safety for therapeutic usage, we have established a completely xeno-free EMSC line derivation protocol using human allogenic umbilical cord serum instead of animal derived reagents, and proved that it is feasible to generate xeno-free EMSC lines from infertile patient donors using these conditions. Our results demonstrate the successful derivation of xeno-free EMSC lines from 10 out of 10 infertile patients. The resultant xeno-free EMSC lines showed typical MSC morphology, phenotypic markers, differentiation capacity, telomere length and normal karyotypes. They showed superior proliferation capability, but lower expression of proto-oncogenes, to the lines generated under standard (animal derived reagents) culture. Biosafety of xeno-free EMSC lines also displayed in retention of immunosuppressive ability, epigenetic stability by imprinted genes expression, proto-oncogenes expression and no mutation of specific codon on p53 tumor suppressor gene. Taken together, these data indicate that our cells may be safe for clinical use. In conclusion, we have succeeded in establishing completely xeno-free EMSC lines and demonstrate for the first time that autogenic and xeno-free EMSC lines can be generated from infertile women.

Role of IGF1R(+) MSCs in modulating neuroplasticity via CXCR4 cross-interaction

To guide the use of human mesenchymal stem cells (MSCs) toward clinical applications, identifying pluripotent-like-markers for selecting MSCs that retain potent self-renewal-ability should be addressed. Here, an insulin-like growth factor 1 receptor (IGF1R)–expressing sub-population in human dental pulp MSCs (hDSCs), displayed multipotent properties. IGF1R expression could be maintained in hDSCs when they were cultured in 2% human cord blood serum (hUCS) in contrast to that in 10% fetal calf serum (FCS). Cytokine array showed that hUCS contained higher amount of several growth factors compared to FCS, including IGF-1 and platelet-derived growth factor (PDGF-BB). These cytokines modulates the signaling events in the hDSCs and potentially enhances engraftment upon transplantation. Specifically, a bidirectional cross-talk between IGF1R/IGF1 and CXCR4/SDF-1α signaling pathways in hDSCs, as revealed by interaction of the two receptors and synergistic activation of both signaling pathways. In rat stroke model, animals receiving IGF1R⁺ hDSCs transplantation, interaction between IGF1R and CXCR4 was demonstrated to promote neuroplasticity, therefore improving neurological function through increasing glucose metabolic activity, enhancing angiogenesis and anti-inflammatiory effects. Therefore, PDGF in hUCS-culture system contributed to the maintenance of the expression of IGF1R in hDSCs. Furthermore, implantation of IGF1R⁺ hDSCs exerted enhanced neuroplasticity via integrating inputs from both CXCR4 and IGF1R signaling pathways.

Human Umbilical Cord Blood-Derived Serum for Culturing the Supportive Feeder Cells of Human Pluripotent Stem Cell Lines

Although human pluripotent stem cells (hPSCs) can proliferate robustly on the feeder-free culture system, genetic instability of hPSCs has been reported in such environment. Alternatively, feeder cells enable hPSCs to maintain their pluripotency. The feeder cells are usually grown in a culture medium containing fetal bovine serum (FBS) prior to coculture with hPSCs. The use of FBS might limit the clinical application of hPSCs. Recently, human cord blood-derived serum (hUCS) showed a positive effect on culture of mesenchymal stem cells. It is interesting to test whether hUCS can be used for culture of feeder cells of hPSCs. This study was aimed to replace FBS with hUCS for culturing the human foreskin fibroblasts (HFFs) prior to feeder cell preparation. The results showed that HFFs cultured in hUCS-containing medium (HFF-hUCS) displayed fibroblastic features, high proliferation rates, short population doubling times, and normal karyotypes after prolonged culture. Inactivated HFF-hUCS expressed important genes, including Activin A, FGF2, and TGFβ1, which have been implicated in the maintenance of hPSC pluripotency. Moreover, hPSC lines maintained pluripotency, differentiation capacities, and karyotypic stability after being cocultured for extended period with inactivated HFF-hUCS. Therefore, the results demonstrated the benefit of hUCS for hPSCs culture system.

Isolation and proliferation of umbilical cord tissue derived mesenchymal stem cells for clinical applications

Umbilical cord (UC) is a rich source of rapidly proliferating mesenchymal stem cells (MSCs) that are easily cultured on a large-scale. Clinical applications of UC-MSCs include graft-versus-host disease, and diabetes mellitus types 1 and 2. UC-MSCs should be isolated and proliferated according to good manufacturing practice (GMP) with animal component-free medium, quality assurance, and quality control for their use in clinical applications. This study developed a GMP standard protocol for UC-MSC isolation and culture. UC blood and UC were collected from the same donors. Blood vasculature was removed from UC. UC blood was used as a source of activated platelet rich plasma (aPRP). Small fragments (1-2 mm(2)) of UC membrane and Wharton's jelly were cut and cultured in DMEM/F12 medium containing 1 % antibiotic-antimycotic, aPRP (2.5, 5, 7.5 and 10 %) at 37 °C in 5 % CO2. The MSC properties of UC-MSCs at passage 5 such as osteoblast, chondroblast and adipocyte differentiation, and markers including CD13, CD14, CD29, CD34, CD44, CD45, CD73, CD90, CD105, and HLA-DR were confirmed. UC-MSCs also were analyzed for karyotype, expression of tumorigenesis related genes, cell cycle, doubling time as well as in vivo tumor formation in NOD/SCID mice. Control cells consisted of UC-MSCs cultured in DMEM/F12 plus 1 % antibiotic-antimycotic, and 10 % fetal bovine serum (FBS). All UC-MSC (n = 30) samples were successfully cultured in medium containing 7.5 and 10 % aPRP, 92 % of samples grew in 5.0 % aPRP, 86 % of samples in 2.5 % aPRP, and 72 % grew in 10 % FBS. UC-MSCs in these four groups exhibited similar marker profiles. Moreover, the proliferation rates in medium with PRP, especially 7.5 and 10 %, were significantly quicker compared with 2.5 and 5 % aPRP or 10 % FBS. These cells maintained a normal karyotype for 15 sub-cultures, and differentiated into osteoblasts, chondroblasts, and adipocytes. The analysis of pluripotent cell markers showed UC-MSCs maintained the expression of the oncogenes Nanog and Oct4 after long term culture but failed to transfer tumors in NOD/SCID mice. Replacing FBS with aPRP in the culture medium for UC tissues allowed the successful isolation of UC-MSCs that satisfy the minimum standards for clinical applications.

Cord Blood Cells for Developmental Toxicology and Environmental Health

The Tox21 program initiated a shift in toxicology toward in vitro testing with a focus on the biological mechanisms responsible for toxicological response. We discuss the applications of these initiatives to developmental toxicology. Specifically, we briefly review current approaches that are widely used in developmental toxicology to demonstrate the gap in relevance to human populations. An important aspect of human relevance is the wide variability of cellular responses to toxicants. We discuss how this gap can be addressed by using cells isolated from umbilical cord blood, an entirely non-invasive source of fetal/newborn cells. Extension of toxicological testing to collections of human fetal/newborn cells would be useful for better understanding the effect of toxicants on fetal development in human populations. By presenting this perspective, we aim to initiate a discussion about the use of cord blood donor-specific cells to capture the variability of cellular toxicological responses during this vulnerable stage of human development.

Feeder-free and xeno-free culture of human pluripotent stem cells using UCBS matrix

The ideal medium for human pluripotent stem cells (hPSCs) culture should be feeder-free, xeno-free, and completely defined. The present study aims to establish a new feeder-free and xeno-free system for culturing hPSCs. The system consists of the matrix, which was prepared from human umbilical cord blood serum (UCBS) and used to coat the culture plates, and the xeno-free medium, which was conventional serum-free hES medium supplemented with high concentrations of bFGF and Fibronectin. Compared with matrigel and mouse embryonic fibroblasts (MEFs), the UCBS matrix was proved to be equally suitable for the growth of hPSCs. After a series of experiments with different media and cytokins, the UCBS matrix was found worked the best with the basic medium (BM) supplemented with 20 ng/mL bFGF, 10 ug/mL fibronectin and Y-27632 for culture of hES cells. The hPSCs maintained normal karyotype, high proliferation rate and self-renewal ability after continuous culture more than 10 passages in this feeder-free and xeno-free system. Furthermore, a new human embryonic stem (hES) cell line was derived from discarded day 3 embryos in this newly developed culture system. In conclusion, this feeder-free and xeno-free system could not only be used to the culture hPSCs, but could also be used to derive new hES cell lines.

A robust and reproducible animal serum-free culture method for clinical-grade bone marrow-derived mesenchymal stromal cells

Efficient xenofree expansion methods to replace fetal bovine serum (FBS)-based culture methods are strongly encouraged by the regulators and are needed to facilitate the adoption of mesenchymal stromal cell (MSC)-based therapies. In the current study we established a clinically-compliant and reproducible animal serum-free culture protocol for bone marrow-(BM-) MSCs based on an optimized platelet-derived supplement. Our study compared two different platelet-derived supplements, platelet lysate PL1 versus PL2, produced by two different methods and lysed with different amounts of freeze–thaw cycles. Our study also explored the effect of a low oxygen concentration on BM-MSCs. FBS-supplemented BM-MSC culture served as control. Growth kinetics, differentiation and immunomodulatory potential, morphology, karyotype and immunophenotype was analysed. Growth kinetics in long-term culture was also studied. Based on the initial results, we chose to further process develop the PL1-supplemented culture protocol at 20 % oxygen. The results from 11 individual BM-MSC batches expanded in the chosen condition were consistent, yielding 6.60 × 10⁹ ± 4.74 × 10⁹ cells from only 20 ml of bone marrow. The cells suppressed T-cell proliferation, displayed normal karyotype and typical MSC differentiation potential and phenotype. The BM-MSCs were, however, consistently HLA-DR positive when cultured in platelet lysate (7.5–66.1 %). We additionally show that culture media antibiotics and sterile filtration of the platelet lysate can be successfully omitted. We present a robust and reproducible clinically-compliant culture method for BM-MSCs based on platelet lysate, which enables high quantities of HLA-DR positive MSCs at a low passage number (p2) and suitable for clinical use.

Production of good manufacturing practice-grade human umbilical cord blood-derived mesenchymal stem cells for therapeutic use

Human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) are multipotent stem cells that can be differentiated into several specific cell types such as adipocytes, osteoblasts, and chondroblasts. They also were demonstrated to trans-differentiate into other cell lineages such as muscle cells and neurons. Thus, they are considered a promising stem cell source for therapeutic use. Here, we describe a method for production of good manufacturing practice-grade human UCB-MSCs for therapeutic use. The obtained UCB-MSCs are free of allogenous or xenogenous proteins. In addition, these MSCs could maintain the MSC phenotype in long-term culture.

MSCs conditioned media and umbilical cord blood plasma metabolomics and composition

Human mesenchymal stem cells (hMSCs) from umbilical cord (UC) blood (UCB) and matrix are tested clinically for a variety of pathologies but in vitro expansion using culture media containing fetal bovine serum (FBS) is essential to achieve appropriate cell numbers for clinical use. Human UCB plasma (hUCBP) can be used as a supplement for hMSCs culture, since UCB is rich in soluble growth factors and due to worldwide increased number of cryopreserved UCB units in public and private banks, without the disadvantages listed for FBS. On the other hand, the culture media enriched in growth factors produced by these hMSCs in expansion (Conditioned medium--CM) can be an alternative to hMSCs application. The CM of the hMSCs from the UC might be a better therapeutic option compared to cell transplantation, as it can benefit from the local tissue response to the secreted molecules without the difficulties and complications associated to the engraftment of the allo- or xeno-transplanted cells. These facts drove us to know the detailed composition of the hUCBP and CM, by 1H-NMR and Multiplexing LASER Bead Technology. hUCBP is an adequate alternative for the FBS and the CM and hUCBP are important sources of growth factors, which can be used in MSCs-based therapies. Some of the major proliferative, chemotactic and immunomodulatory soluble factors (TGF-β, G-CSF, GM-CSF, MCP-1, IL-6, IL-8) were detected in high concentrations in CM and even higher in hUCBP. The results from 1H-NMR spectroscopic analysis of CM endorsed a better understanding of hMSCs metabolism during in vitro culture, and the relative composition of several metabolites present in CM and hUCBP was obtained. The data reinforces the potential use of hUCBP and CM in tissue regeneration and focus the possible use of hUCBP as a substitute for the FBS used in hMSCs in vitro culture.

Reconstruction of Hyaline Cartilage Deep Layer Properties in 3-Dimensional Cultures of Human Articular Chondrocytes

Background:

Articular cartilage (AC) injuries and malformations are commonly noticed because of trauma or age-related degeneration. Many methods have been adopted for replacing or repairing the damaged tissue. Currently available AC repair methods, in several cases, fail to yield good-quality long-lasting results, perhaps because the reconstructed tissue lacks the cellular and matrix properties seen in hyaline cartilage (HC).

Purpose:

To reconstruct HC tissue from 2-dimensional (2D) and 3-dimensional (3D) cultures of AC-derived human chondrocytes that would specifically exhibit the cellular and biochemical properties of the deep layer of HC.

Study Design:

Descriptive laboratory study.

Methods:

Two-dimensional cultures of human AC–derived chondrocytes were established in classical medium (CM) and newly defined medium (NDM) and maintained for a period of 6 weeks. These cells were suspended in 2 mm–thick collagen I gels, placed in 24-well culture inserts, and further cultured up to 30 days. Properties of chondrocytes, grown in 2D cultures and the reconstructed 3D cartilage tissue, were studied by optical and scanning electron microscopic techniques, immunohistochemistry, and cartilage-specific gene expression profiling by reverse transcription polymerase chain reaction and were compared with those of the deep layer of native human AC.

Results:

Two-dimensional chondrocyte cultures grown in NDM, in comparison with those grown in CM, showed more chondrocyte-specific gene activity and matrix properties. The NDM-grown chondrocytes in 3D cultures also showed better reproduction of deep layer properties of HC, as confirmed by microscopic and gene expression analysis. The method used in this study can yield cartilage tissue up to approximately 1.6 cm in diameter and 2 mm in thickness that satisfies the very low cell density and matrix composition properties present in the deep layer of normal HC.

Conclusion:

This study presents a novel and reproducible method for long-term culture of AC-derived chondrocytes and reconstruction of cartilage tissue with properties similar to the deep layer of HC in vitro.

Clinical Relevance:

The HC tissue obtained by the method described can be used to develop an implantable product for the replacement of damaged or malformed AC, especially in younger patients where the lesions are caused by trauma or mechanical stress.

Derivation, expansion and characterization of clinical grade mesenchymal stem cells from umbilical cord matrix using cord blood serum

BACKGROUND AND OBJECTIVES

With increasing use of mesenchymal stem cells (MSCs) in regenerative medicine, there is greater awareness towards the need to have clinical grade products. The bovine media currently used allow good expansion to give large number of MSCs of the right quality. This report brings the significance of using cord blood serum (CBS) in the derivation of MSCs from umbilical cord matrix, to help its clinical applicability.

METHODS AND RESULTS

MSCs isolated from the cord by explant cultures were expanded and characterized by flow cytometry. Cord blood serum while helping expansion, has the ability to preserve the immunophenotype and differentiation potential of the MSCs derived from the umbilical cords.

CONCLUSIONS

Our results suggest that MSCs derived and expanded in cord blood serum are better suited for clinical applications.

Good manufacturing practice-compliant isolation and culture of human umbilical cord blood-derived mesenchymal stem cells

Background

Mesenchymal stem cells (MSCs) are an attractive source of stem cells for clinical applications. These cells exhibit a multilineage differentiation potential and strong capacity for immune modulation. Thus, MSCs are widely used in cell therapy, tissue engineering, and immunotherapy. Because of important advantages, umbilical cord blood-derived MSCs (UCB-MSCs) have attracted interest for some time. However, the applications of UCB-MSCs are limited by the small number of recoverable UCB-MSCs and fetal bovine serum (FBS)-dependent expansion methods. Hence, this study aimed to establish a xenogenic and allogeneic supplement-free expansion protocol.

Methods

UCB was collected to prepare activated platelet-rich plasma (aPRP) and mononuclear cells (MNCs). aPRP was applied as a supplement in Iscove modified Dulbecco medium (IMDM) together with antibiotics. MNCs were cultured in complete IMDM with four concentrations of aPRP (2, 5, 7, or 10%) or 10% FBS as the control. The efficiency of the protocols was evaluated in terms of the number of adherent cells and their expansion, the percentage of successfully isolated cells in the primary culture, surface marker expression, and in vitro differentiation potential following expansion.

Results

The results showed that primary cultures with complete medium containing 10% aPRP exhibited the highest success, whereas expansion in complete medium containing 5% aPRP was suitable. UCB-MSCs isolated using this protocol maintained their immunophenotypes, multilineage differentiation potential, and did not form tumors when injected at a high dose into athymic nude mice.

Conclusion

This technique provides a method to obtain UCB-MSCs compliant with good manufacturing practices for clinical application.

A rapid and efficient method for primary culture of human adipose-derived stem cells

Adipose tissue contains some populations, adipose-derived stem cells (ADSCs) which can differentiate into adipogenic, chondrogenic, osteogenic, myogenic, and endothelial cells. Furthermore, adipose tissue can be easily obtained in large quantities through a simple liposuction. ADSCs are thought to be an alternate source of autologous adult stem cells for cell-based therapy. However, it is time-consuming and inefficient to harvest ADSCs by using a traditional collagenase-digestion method. To meet the demand of large quantities of ADSCs in the basic and applied research of regenerative medicine, we developed a rapid and efficient method for isolation and culture of primary ADSCs. The results indicated that the ADSCs obtained with our method possessed strong abilities of proliferation and colony formation in vitro, and could keep low level of cell senescence with stable population doubling during long-term culture in vitro. Furthermore, these harvested ADSCs were capable to differentiate into osteogenic and adipogenic lineages in the specific induction medium. In addition, the results of flow cytometry analysis indicated that these ADSCs could positively express multiple CD markers, such as CD44, CD105, CD29, CD90, and CD13, and hardly expressed CD31, CD34, CD45, and CD106, which was homologous to the mesenchymal stem cells. Therefore, the ADSCs isolated with our method are consistent with previously reported characteristics of the ADSCs. This new method that we established in this study is an efficient tool to isolate and culture the stem cells from adipose tissue.

A xeno-free culture method that enhances Wharton's jelly mesenchymal stromal cell culture efficiency over traditional animal serum-supplemented cultures

BACKGROUND AIMS

Mesenchymal stromal cell (MSC) transplantation holds great promise for use in medical therapies. Several key features of MSCs, including efficient cell growth, generation of sufficient cell numbers and safety, as determined by teratoma formation, make MSCs an ideal candidate for clinical use. However, MSCs derived under standard culture conditions, co-cultured with animal by-products, are inappropriate for therapy because of the risks of graft rejection and animal virus transmission to humans. Alternative serum sources have been sought for stem cell production.

METHODS

We demonstrate for the first time that human serum from umbilical cord blood (hUCS) is an effective co-culture reagent for MSC production from Wharton's jelly MSCs (WJMSCs). Ten umbilical cords were used to generate parallel cultures of WJMSC lines under medium supplemented with hUCS and embryonic stem cell-qualified fetal bovine serum. The WJMSC lines from each medium were analyzed and compared with regard to cell line derivation, proliferation ability and characteristic stability.

RESULTS

The phenotypic characteristics of WJMSC derived under either medium showed no differences. WJMSC lines derived under hUCS medium displayed comparable primary culture cell outgrowth, lineage differentiation capacity and cell recovery after cryopreservation compared with supplementation with embryonic stem cell-qualified fetal bovine serum medium. However, superior cell proliferation rates and retention of in vitro propagation (>22 passages) were observed in WJMSC cultures supplemented with hUCS. Additionally, more robust population doubling times were observed in hUCS-supplemented cultures.

CONCLUSIONS

We conclude that hUCS is an efficient and effective serum source for animal product-free WJMSC line production and can generate MSC lines that may be appropriate for therapeutic use.

Human umbilical cord-derived MSC culture: the replacement of animal sera with human cord blood plasma

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) hold great potential for their therapeutic use in various clinical diseases. Many publications have reported on human blood-derived alternatives to animal serum for culturing mesenchymal stem cells, such as human serum, allogenic umbilical cord blood serum, and human platelet derivatives. However, it is not clear whether human umbilical cord blood plasma (UCBP), as the surplusage of umbilical cord blood mesenchymal stem cell extraction, could be used. In this study, in order to make the best of umbilical cord blood, the human UCBP was dialyzed to replace fetal bovine serum (FBS) in the culture medium. hUC-MSCs were cultured in the new medium. Cell growth rate, specific biomarkers, and differentiation properties were detected to characterize the cell proliferation and MSC-specific properties. The hUC-MSCs cultured in such derived medium were verified with proliferation rate, cluster differentiation markers, cell cycle, as well as differentiation capabilities. Such dialyzed human UCBP is fully comparable with, if not superior to, FBS in deriving and culturing hUC-MSCs.

Regulation and direction of umbilical cord blood mesenchymal stem cells to adopt neuronal fate

Umbilical cord blood mesenchymal stem cells (UCB-MSCs) transplantation is becoming a promising and attractive cell-based treatment modality for repairing the damaged central nervous system due to its advantages of low immunogenicity, wide range of sources, and less ethical controversy. One of the limitations of this approach is that the proportion of neurons differentiated from UCB-MSCs still remains at low level. Thus, to induce UCB-MSCs to differentiate into neuron-like cells with a higher proportion is one of the key technologies of regenerative medicine and tissue engineering. Many induction protocols with remarkably higher differentiation rate to neurons have been reported. However, each protocol has its pros and cons and whether the neurons differentiated from UCB-MSCs under a certain protocol has normal nerve function remains controversial. Therefore, to guarantee the success of future clinical applications of UCB-MSCs, more investigations should be performed to improve the induction method and differentiation efficiency.

Autogenic feeder free system from differentiated mesenchymal progenitor cells, maintains pluripotency of the MEL-1 human embryonic stem cells

Human embryonic stem cells (hESc) are known for its pluripotency and self renewal capability, thus possess great potential in regenerative medicine. However, the lack of suitable xenofree extracellular matrix substrate inhibits further applications or the use of hESc in cell-based therapy. In this study, we described a new differentiation method, which generates a homogeneous population of mesenchymal progenitor cells (hESc-MPC) from hESc via epithelial-mesenchymal transition. The extracellular matrix (ECM) proteins from hESc-MPC had in turn supported the undifferentiated expansion of hESc. Immunocytochemistry and flow cytometry characterization of hESc-MPC revealed the presence of early mesenchymal markers. Tandem mass spectometry analysis of ECM produced by hESc-MPC revealed the presence of a mixture of extracellular proteins which includes tenascin C, fibronectin, and vitronectin. The pluripotency of hESc (MEL-1) cultured on the ECM was maintained as shown by the expression of pluripotent genes (FoxD3, Oct-4, Tdgf1, Sox-2, Nanog, hTERT, Rex1), protein markers (SSEA-3, SSEA-4, TRA-1-81, TRA-1-60, Oct-4) and the ability to differentiate into cells representative of ectoderm, endoderm and mesoderm. In summary, we have established a xeno-free autogenic feeder free system to support undifferentiated expansion of hESc, which could be of clinical relevance.

Aggregation of Human Eyelid Adipose-derived Stem Cells by Human Body Fluids

Fetal bovine serum (FBS) is the most frequently used serum for the cultivation of mammalian cells. However, since animal-derived materials might not be appropriate due to safety issues, allogeneic human serum (HS) has been used to replace FBS, particularly for the culture of human cells. While there has been a debate about the advantages of HS, its precise effect on human adult stem cells have not been clarified. The present study aimed to investigate the effect of HS on the human eyelid adipose stem cells (HEACs) in vitro. When HEACs were cultivated in a medium containing 10% HS, many cells moved into several spots and aggregated there. The phenomenon was observed as early as 9 days following 10% HS treatment, and 12 days following 5% HS plus 5% FBS treatment. However, the aggregation was never observed when the same cells were cultivated with 10% FBS or bovine serum albumin. To examine whether cell density might affect the aggregation, cells were seeded with different densities on 12-well dish. Until the beginning of aggregation, cells seeded at low densities exhibited the longest culture period of 16 days whereas cells seeded at high densities showed the shortest period of 9 days to form aggregation. The number of cells was 15.1±0.2×10⁴ as the least for the low density group, and 29.3±2.8×10⁴ as the greatest for the high density group. When human cord blood serum or normal bovine serum was examined for the same effect on HEACs, interestingly, cord blood serum induced the aggregation of cells whereas bovine serum treatment has never induced. When cells were cultivated with 10% HS for 9 days, they were obtained and analyzed by RT-PCR. Compared to FBS-cultivated HEACs, HS-cultivated HEACs did not express VIM, and less expressed GATA4, PALLD. On the other hand, HS-cultivated HEACs expressed MAP2 more than FBS-cultivated HEACs. In conclusion, human adult stem cells could move and form aggregates by the treatment with human body fluids.

Characterization of placenta-derived mesenchymal stem cells cultured in autologous human cord blood serum

Human placenta-derived mesenchymal stem cells (P-MSCs) have drawn increasing attention in the field of stem cell research due to their potential in clinical applications as well as their rich and easy to procure cell source. While studies demonstrating the potential of P-MSCs for therapeutic transplantations have been documented, a clinically compliant procedure for P-MSC expansion in vitro has yet to be established. To this end, previous studies have demonstrated that MSCs of bone marrow and cord blood origins cultured in human cord blood serum (hCBS) are comparable to those cultured in fetal bovine serum (FBS), indicating that hCBS may be an alternative to FBS for the development of in vitro cell expansion procedures free of animal components. However, stem cells from origins other than bone marrow or cord blood, particularly from human placental tissues, which have demonstrated a good potential for clinical applications, have not been characterized under similar conditions. In this study, in an attempt to define a clinically compliant protocol for P-MSC expansion in vitro, we examined the effects of human hCBS as a replacement for FBS on cell proliferation capacity, differentiation potential, MSC-specific phenotypic expression and the genetic stability of P-MSCs in cultures. P-MSCs expanded in vitro in autologous hCBS maintained the capacity of self‑renewal and expressed surface antigens characteristic of bone marrow-derived mesenchymal stem cells. Under differentiation conditions, the P-MSCs expanded in hCBS developed into adipogenic, osteogenic and neurogenic cell phenotypes. Chromosomal karyotyping and single cell gel electrophoresis analysis demonstrated that P-MSCs cultured in autologous hCBS were genetically stable. These results suggest that autologous hCBS may be used as an alternative to FBS for the in vitro expansion of P-MSCs for clinical applications.

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.

Upregulation of Adipogenesis and Chondrogenesis in MSC Serum-Free Culture

Serum-free media have been shown to be effective in the expansion of mesenchymal stem cells (MSCs). However, the effects may go beyond cell expansion as the differentiation potentials of the cells may be modified, thus influencing their efficacy for downstream applications. The latter is poorly understood, and this has prompted an evaluation of the influence of a serum-free formulation on the chondrogenic, adipogenic, and osteogenic potential of MSCs. The media consisted of Knockout™ Serum Replacement (KSR) with a cocktail of growth factors coupled with either collagen or fibronectin coatings. Collagen coating was selected as it promoted consistent cellular attachment. When compared against fetal bovine serum (FBS) controls, cell proliferation in the serum-free media was enhanced at passage 1. Similar levels of surface markers were observed in the two groups with a slight reduction in CD90 and CD73 in the serum-free culture at passage 3. The cultures were screened under differentiation conditions and a better maintenance of the chondrogenic potential was noted in the serum-free media with higher expressions of glycoaminoglycans (GAGs) and collagen II. Chondrogenesis was deficient in the FBS group and this was attributed to the inherent inconsistency of animal serum. Adipogenesis was enhanced in the serum-free group with a higher PPARG expression and lipid accumulation. Similar levels of osteogenic mineralization was noted in the FBS and serum-free groups but collagen I gene expression was suppressed in the latter. This was initially observed during expansion. These observations were attributed to the signaling cascades triggered by the cytokines presented in the serum-free formulation and the interaction with the collagen substrate. The serum-free media helps to maintain and enhance the chondrogenic and adipogenic potentials of the MSCs, respectively. This advantage can be exploited for therapeutic applications in cartilage and adipose tissue engineering.

Enhanced neogenic potential of Panc-1 cells supplemented with human umbilical cord blood serum--An alternative to FCS

The promise(s) of using Fetal Calf Serum (FCS) as a supplement for the maintenance of cell cultures has been well documented. However, FCS forms the xenogenic source for any human derived cells/organ and limits its application. Recently, the usage of human umbilical cord blood serum (hUCBS) for maintenance of mesenchymal cells has been supportive. In the present study we investigated the effects of hUCBS and FCS on the proliferation (viability, proliferative) and its differentiation potential (DTZ staining, immunofluroscence) to generate islet like cellular aggregates (ICAs) using the human derived Panc-1 cell lines. A comparative analysis of hUCBS and FCS for each parameter demonstrated that hUCBS supplemented media was better for proliferation and differentiation of the Panc-1 cells. The ICAs obtained from hUCBS primed cultures showed a higher yield, increased islet size, and showed an increase for insulin staining compared to FCS. We suggest that hUCBS can be explored as an alternate serum supplement for FCS, making it more feasible in cell systems of human derived origin and can also find its application for the human transplantation programmes.

Human breast milk is a rich source of multipotent mesenchymal stem cells

Putative stem cells have been isolated from various tissue fluids such as synovial fluid, amniotic fluid, menstrual blood, etc. Recently the presence of nestin positive putative mammary stem cells has been reported in human breast milk. However, it is not clear whether they demonstrate multipotent nature. Since human breast milk is a non-invasive source of mammary stem cells, we were interested in examining the nature of these stem cells. In this pursuit, we could succeed in isolating and expanding a mesenchymal stem cell-like population from human breast milk. These cultured cells were examined by immunofluorescent labeling and found positive for mesenchymal stem cell surface markers CD44, CD29, SCA-1 and negative for CD33, CD34, CD45, CD73 confirming their identity as mesenchymal stem cells. Cytoskeletal protein marker analysis revealed that these cells expressed mesenchymal stem cells markers, namely, nestin, vimentin, smooth muscle actin and also manifests presence of E-Cadherin, an epithelial to mesenchymal transition marker in their early passages. Further we tested the multipotent differentiation potential of these cells and found that they can differentiate into adipogenic, chondrogenic and oesteogenic lineage under the influence of specific differentiation cocktails. This means that these mesenchymal stem cells isolated from human breast milk could potentially be "reprogrammed" to form many types of human tissues. The presence of multipotent stem cells in human milk suggests that breast milk could be an alternative source of stem cells for autologous stem cell therapy although the significance of these cells needs to be determined.

Culture and in vitro hepatogenic differentiation of placenta-derived stem cells, using placental extract as an alternative to serum

OBJECTIVES

Translational research using adult stem cells derived from various tissues has been highlighted in cell-based therapy. However, there are many limitations to using conventional culture systems of adult stem cells for clinically applicability, including limited combinations of cytokines and use of nutrients derived from animals. Here, we have investigated the effects of placental extract (PE) for culture of placenta-derived stem cells (PDSCs) as well as their potential for hepatogenic differentiation.

MATERIALS AND METHODS

Placental extract, extracted using water-soluble methods, was used as a supplement for culture of PDSCs. Cell viability was determined using the MTT assay, and cytokine assay was performed using Luminex assay kit. Gene expression, indocyanine green (ICG) up-take, PAS (Periodic Acid-Schiff) staining and urea production were also analysed.

RESULTS

The placental extract contained several types of cytokine and chemokine essential for maintenance and differentiation of stem cells. Expression of stemness markers in PDSCs cultured with PE is no different from that of PDSCs cultured with foetal bovine serum (FBS). After hepatogenic differentiation, expression patterns for hepatocyte-specific markers in PDSCs cultured with PE were consistent and potential for hepatogenic differentiation of PDSCs cultured with PE was similar to that of PDSCs cultured with FBS, as shown by PAS staining and urea production assays.

CONCLUSIONS

Our findings revealed that placental extract could be used as a new component for culture of adult stem cells, as well as for development of human-based medium, in translational research for regenerative medicine.