Umbilical cord transplantation: epilogue

Enhancement of proliferation of human umbilical cord blood–derived CD34+ hematopoietic stem cells by a combination of hyper-interleukin-6 and small molecules

Umbilical cord blood (UCB) is an alternative source of allogeneic hematopoietic stem cells (HSCs) for transplantation to treat various hematological disorders. The major limitation to the use of UCB-derived HSCs (UCB–HSCs) in transplantation, however, is the low numbers of HSCs in a unit of cord blood. To overcome this limitation, various cytokines or small molecules have been used to expand UCB-HSCs ex vivo. In this study, we investigated a synergistic effect of the combination of HIL-6, SR1, and UM171 on UCB-HSC culture and found that this combination resulted in the highest number of CD34⁺ cells. These results suggest that the combination of SR1, UM171 and HIL-6 exerts a synergistic effect in the proliferation of HSCs from UCB and thus, SR1, UM171 and HIL-6 is the most suitable combination for obtaining HSCs from UCB for clinical transplantation.

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Hyper IL-6 enhances the proliferation of both total nucleated cells and CD34⁺ cells.

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The combination of SR1 and UM171 with Hyper IL-6 led to increases in TNC and CD34⁺ cells number exvivo human cord blood HSCs.

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It potentially provides an optimization to achieving a successful strategy through exvivo expansion of HSCs for application.

Elevated expression of DNMT1 is associated with increased expansion and proliferation of hematopoietic stem cells co-cultured with human MSCs

Background

Mesenchymal stem cells (MSCs) play an important role in hematopoietic stem cell (HSC) maintenance, proliferation, and apoptosis. DNA methyltransferase 1 (DNMT1) is considered an essential factor in the maintenance of HSCs in mammalian cells. Therefore, this study was conducted to evaluate the mRNA expression level of DNMT1 during cord blood (CB)-HSC ex vivo expansion with MSCs.

Methods

Ex vivo cultures of CB-HSCs were performed in three culture conditions for 7 days: cytokines, cytokines with MSCs, and only MSCs. Total and viable cell numbers were counted after 5 and 7 days using trypan blue stain, and the stem cell percentage was then evaluated by flow cytometry. Moreover, in vitro colony-forming unit assay was carried out to detect clonogenic potential of HSCs at days 0 and 7 using MethoCult H4434. Finally, DNMT1 mRNA expression level was evaluated by real-time polymerase chain reaction.

Results

Maximum CB-CD34⁺ cell expansion was observed on day 7 in all the three cultures. After 7 days, ex vivo expansion of CB-CD34⁺ cells indicated a significant decrease in DNMT1 expression in the cytokine cultures, whereas in the two co-culture conditions DNMT1 expression was increased. A significant difference between the number of CD34⁺ and CD34⁻ cells in the cytokine co-culture system was observed.

Conclusion

These data indicated that an elevated expression of DNMT1 is associated with increased expansion and proliferation of HSCs co-cultured with human MSCs. Hence, DNMT1 may be a potential factor in the maintenance of expanded HSCs co-cultured with human MSCs.

Apoptosis, DAP-Kinase1 Expression and the Influences of Cytokine Milieu and Mesenchymal Stromal Cells on Ex Vivo Expansion of Umbilical Cord Blood-Derived Hematopoietic Stem Cells

Expansion of umbilical cord blood-derived CD34(+) cells can potentially provide them in numbers sufficient for clinical applications in adult humans. In this study apoptosis rate of expanded cells, mRNA expression and promoter methylation status of DAPK1 were evaluated during cord blood hematopoietic stem cell (CB-HSC) ex vivo expansion using cytokines and a co-culture system with mesenchymal stromal cells (MSCs). Ex vivo cultures of CB-HSCs were performed in three culture conditions for 14 days: cytokines with MSCs feeder layer, cytokines without MSCs feeder layer and co-culture with MSCs feeder layer without cytokine. Total number of cells, CD34(+) cells and colony forming unit assay were performed during expansion. Flow cytometric analysis by propidium iodide was performed to detection of apoptosis rate in expanded cells. Methylation status of the DAPK1 gene promoter was analyzed using methylation specific PCR, and DAPK1 mRNA expression was evaluated by real time-PCR. Maximum CB-CD34(+) cells expansion was observed in day 10 of expansion. The highest apoptosis rate was observed in cytokine culture without feeder layer that showed significant difference with co-culture condition. The data showed that ex vivo expansion of CD34(+) cells in all three culture conditions after 10 days resulted in, significant increased expression of DAPK1, also a significant difference between co-culture without cytokine and two other cytokine culture was observed (p < 0.01). DAPK1gene promoter of expanded CD34(+) cells at days 5, 10 and 14 of culture remained in unmethylated form similar to fresh CD34(+) cells. Expression of DAPK1 in hematopoietic cells was increased during 10 days expansion of CD34(+) cells. Also no methylation of DAPK1 promoter was observed; otherwise it would be capable of initiating some leukemic cell progression or disruption in hematopoietic regeneration.

An experimental approach to the generation of human embryonic stem cells equivalents

Recently, particular attention has been paid to the human embryonic stem cells (hESC) in the context of their potential application in regenerative medicine; however, ethical concerns prevent their clinical application. Induction of pluripotency in somatic cells seems to be a good alternative for hESC recruitment regarding its potential use in tissue regeneration, disease modeling, and drug screening. Since Yamanaka's team in 2006 restored pluripotent state of somatic cells for the first time, a significant progress has been made in the area of induced pluripotent stem cells (iPSC) generation. Here, we review the current state of knowledge in the issue of techniques applied to establish iPSC. Somatic cell nuclear transfer, cell fusion, cell extracts reprogramming, and techniques of direct reprogramming are described. Retroviral and lentiviral transduction are depicted as ways of cell reprogramming with the use of integrating vectors. Contrary to them, adenoviruses, plasmids, single multiprotein expression vectors, and PiggyBac transposition systems are examples of non-integrative vectors used in iPSC generation protocols. Furthermore, reprogramming with the delivery of specific proteins, miRNA or small chemical compounds are presented. Finally, the changes occurring during the reprogramming process are described. It is concluded that subject to some limitations iPSC could become equivalents for hESC in regenerative medicine.

Expression and promoter methylation changes of the P15INK4b during ex vivo cord blood CD34+ cell expansion following co-culture with mesenchymal stromal cells

BACKGROUND

Because of the insufficient number of cord blood hematopoietic stem cells (CB-HSC), expansion of these cells seems to be important for clinical application in adults. Cell cycle inhibitors are important regulators in normal hematopoietic regeneration. In this study, mRNA expression and promoter methylation status of p15(INK4b) were evaluated during CB-HSC ex vivo expansion using cytokines and in co-culture system with a mesenchymal stem cells (MSCs) feeder layer.

METHODS

ex vivo cultures of CB-HSCs were performed in three culture conditions for 14 days: cytokines with an MSCs feeder layer, cytokines without a MSCs feeder layer, and co-culture with MSCs without cytokines. After expansion, measuring the total number of cells, CD34(+) cells, and CFU assay was performed. Methylation status of the p15(INK4b) gene promoter was analyzed using methylation-specific polymerase chain reaction and p15 mRNA expression was evaluated by real-time reverse transcriptase polymerase chain reaction.

RESULTS

Maximum CB-HSC expansion was observed on day 10 of expansion. The data showed that after 10 days, p15 mRNA expression in the expanded cells in all the three culture conditions was higher than in CD34(+) fresh cells (P < 0.01). p15 gene promoter of expanded CD34(+) cells remained in an unmethylated form just like fresh CD34(+) cells in all the three culture conditions at days 5, 10, and 14 of culture.

CONCLUSIONS

Expression of p15(INK4b) in HSCs was not decreased during ex vivo expansion. Also, no methylation of p15 promoter was observed, otherwise it would be capable of initiating some leukemic cell progression or disruption in hematopoietic regeneration.

Unravelling the pluripotency paradox in fetal and placental mesenchymal stem cells: Oct-4 expression and the case of The Emperor's New Clothes

Mesenchymal stem cells (MSC) from fetal-placental tissues have translational advantages over their adult counterparts, and have variably been reported to express pluripotency markers. OCT-4 expression in fetal-placental MSC has been documented in some studies, paradoxically without tumourogenicity in vivo. It is possible that OCT-4 expression is insufficient to induce true "stemness", but this issue is important for the translational safety of fetal-derived MSC. To clarify this, we undertook a systematic literature review on OCT-4 in fetal or adnexal MSC to show that most studies report OCT-4 message or protein expression, but no study provides definitive evidence of true OCT-4A expression. Discrepant findings were attributable not to different culture conditions, tissue sources, or gestational ages but instead to techniques used. In assessing OCT-4 as a pluripotency marker, we highlight the challenges in detecting the correct OCT-4 isoform (OCT-4A) associated with pluripotency. Although specific detection of OCT-4A mRNA is achievable, it appears unlikely that any antibody can reliably distinguish between OCT-4A and the pseudogene OCT-4B. Finally, using five robust techniques we demonstrate that fetal derived-MSC do not express OCT-4A (or by default OCT-4B). Reports suggesting OCT-4 expression in fetal-derived MSC warrant reassessment, paying attention to gene and protein isoforms, pseudogenes, and antibody choice as well as primer design. Critical examination of the OCT-4 literature leads us to suggest that OCT-4 expression in fetal MSC may be a case of "The Emperor's New Clothes" with early reports of (false) positive expression amplified in subsequent studies without critical attention to emerging refinements in knowledge and methodology.

Mesenchymal stem cells as a feeder layer can prevent apoptosis of expanded hematopoietic stem cells derived from cord blood

Umbilical cord blood (UCB) has been used for transplantation in the treatment of hematologic disorders as a source of hematopoietic stem cells (HSCs). Because of insufficient number of cord blood CD34(+) cells, the expansion of these cells seems to be important for clinical application. Mesenchymal stromal cells (MSCs), playing an important role in HSCs maintenance, were used as feeder layer. Apoptosis and cell cycle distribution of expanded cells were analyzed in MSCs co-culture and cytokine conditions and results were compared. Three culture conditions of cord blood HSCs were prepared ex-vivo for 14 days: cytokines (SCF, TPO and Flt3L) with MSCs feeder layer, cytokines without MSCs feeder layer and co-culture with MSCs without cytokines. Expansion was followed by measuring the total nucleated cells (TNCs), CD34(+) (‏) cells and colony-forming unit (CFU) output. Flow cytometry analysis of stained cells by annexin V and propidium iodide was performed for detection of apoptosis rate and cell cycle distribution in expanded cells. Maximum cord blood CD34(+) cells expansion was observed in day 10. The mean fold change of TNCs and CD34+ cells at day 10 in the co-culture system with cytokines was significantly higher than the cytokine culture without MSCs feeder layer and co-culture system without cytokines (n=6, p=0.023). The highest apoptosis rate and the least number of cells in Go/G1 phase were observed in cytokine culture without feeder layer (p=0.041). The expansion of cord blood HSCs on MSCs as a feeder layer resulted in higher proliferation and reduction in apoptosis rate.

Stem cell-derived erythrocytes as upcoming players in blood transfusion

BACKGROUND

Blood transfusion is current standard-of-care for genetic forms of anemia that would be otherwise lethal and allows implementation of aggressive cytotoxic/surgical therapies developed for numerous types of cancer. In developed countries the blood supply is adequate and sporadically even in excess. However, difficulties exist in finding blood with rare phenotypes to treat alloimmunized patients and the progressive ageing of the human population predicts that blood will become scarce by 2050. These considerations establish the need for the development of techniques to generate cultured red blood cell (cRBCs) as transfusion products.

MATERIALS AND METHODS

Recent progress in cell culture techniques is revolutionizing organ replacement therapies. Two new disciplines, cell therapy and tissue engineering, have been developed to generate in vitro therapeutic products for a variety of applications ranging from skin grafts to organ-function repairs. It is currently believed that these advances will eventually allow ex-vivo production of various cell types in numbers so great that, in the case of red cells, would be clinically adequate for transfusion.

RESULTS

Proof-of-principle in animal models indicate that cRBCs generated from murine embryonic stem cells protect mice from lethal anemia. Conditions to generate small amounts of clinical grade cRBCs have been established and the first-in-man administration of autologous cRBCs perfomed. The results of this trial indicate that cRBCs survive in vivo at least as long as their natural counterpart.

DISCUSSION

These ground-breaking reports have raised great excitement for clinical evaluation of cRBCs for transfusion. However, skepticism still persist that production of cRBCs in numbers sufficient for transfusion will ever be possible. This paper will discuss diagnostic and clinical goals pursuable with numbers of cRBCs that may be generated with current technology.

CONCLUSION

We are confident that development of relevant clinical goals achievable with current technologies will not only improve clinical care in transfusion medicine but will also foster studies to overcome scientific and technical barriers that render transfusion with cRBCs of the general population impractical today.

New strategies in cord blood cells transplantation

For patients lacking a human leucocyte antigen-matched donor, umbilical cord blood (UCB) is an ideal, alternative source of haematopoietic stem cells (HSCs) for transplantation purposes. UCB has many advantages over bone marrow or peripheral blood taken from volunteer donors. UCB is also an important source of other stem cells, including endothelial progenitors, mesenchymal stem cells, very small embryonic/epiblast-like (VSEL) stem cells, and unrestricted somatic stem cells, which are potentially suitable for regenerative medicine. However, a significant clinical problem is that the number of HSCs in one cord-blood unit is not enough for an adult transplantation. The development of new approaches including use of multiple donors, ex vivo expansion, increasing efficiency of homing and engraftment, retrieving more cells from the placenta and cord blood is of crucial importance for the delayed engraftment after UCB transplantation. In the future, UCB will emerge as a source of cells for cellular therapies associated with tissue repair and regeneration.

Concise review: stem cell-derived erythrocytes as upcoming players in blood transfusion

Blood transfusions have become indispensable to treat the anemia associated with a variety of medical conditions ranging from genetic disorders and cancer to extensive surgical procedures. In developed countries, the blood supply is generally adequate. However, the projected decline in blood donor availability due to population ageing and the difficulty in finding rare blood types for alloimmunized patients indicate a need for alternative red blood cell (RBC) transfusion products. Increasing knowledge of processes that govern erythropoiesis has been translated into efficient procedures to produce RBC ex vivo using primary hematopoietic stem cells, embryonic stem cells, or induced pluripotent stem cells. Although in vitro-generated RBCs have recently entered clinical evaluation, several issues related to ex vivo RBC production are still under intense scrutiny: among those are the identification of stem cell sources more suitable for ex vivo RBC generation, the translation of RBC culture methods into clinical grade production processes, and the development of protocols to achieve maximal RBC quality, quantity, and maturation. Data on size, hemoglobin, and blood group antigen expression and phosphoproteomic profiling obtained on erythroid cells expanded ex vivo from a limited number of donors are presented as examples of the type of measurements that should be performed as part of the quality control to assess the suitability of these cells for transfusion. New technologies for ex vivo erythroid cell generation will hopefully provide alternative transfusion products to meet present and future clinical requirements.

Insights and hopes in umbilical cord blood stem cell transplantations

Over 20.000 umblical cord blood transplantations (UCBT) have been carried out around the world. Indeed, UCBT represents an attractive source of donor hematopoietic stem cells (HSCs) and, offer interesting features (e.g., lower graft-versus-host disease) compared to bone marrow transplantation (BMT). Thereby, UCBT often represents the unique curative option against several blood diseases. Recent advances in the field of UCBT, consisted to develop strategies to expand umbilical stem cells and shorter the timing of their engraftment, subsequently enhancing their availability for enhanced efficacy of transplantation into indicated patients with malignant diseases (e.g., leukemia) or non-malignant diseases (e.g., thalassemia major). Several studies showed that the expansion and homing of UCBSCs depends on specific biological factors and cell types (e.g., cytokines, neuropeptides, co-culture with stromal cells). In this review, we extensively present the advantages and disadvantages of current hematopoietic stem cell transplantations (HSCTs), compared to UBCT. We further describe the importance of cord blood content and obstetric factors on cord blood selection, and report the recent approaches that can be undertook to improve cord blood stem cell expansion as well as engraftment. Eventually, we provide two majors examples underlining the importance of UCBT as a potential cure for blood diseases.

Transplantation of umbilical cord-derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives

The prevention of perinatal neurological disabilities remains a major challenge for public health, and no neuroprotective treatment to date has proven clinically useful in reducing the lesions leading to these disabilities. Efforts are, therefore, urgently needed to test other neuroprotective strategies including cell therapies. Although stem cells have raised great hopes as an inexhaustible source of therapeutic products that could be used for neuroprotection and neuroregeneration in disorders affecting the brain and spinal cord, certain sources of stem cells are associated with potential ethical issues. The human umbilical cord (hUC) is a rich source of stem and progenitor cells including mesenchymal stem cells (MSCs) derived either from the cord or from cord blood. hUC MSCs (hUC-MSCs) have several advantages as compared to other types and sources of stem cells. In this review, we will summarize the most recent findings regarding the technical aspects and the preclinical investigation of these promising cells in neuroprotection and neuroregeneration, and their potential use in the developing human brain. However, extensive studies are needed to optimize the administration protocol, safety parameters, and potential preinjection cell manipulations before designing a controlled trial in human neonates.

Stem cell therapy for neonatal brain injury: perspectives and challenges

Cerebral palsy is a major health problem caused by brain damage during pregnancy, delivery, or the immediate postnatal period. Perinatal stroke, intraventricular hemorrhage, and asphyxia are the most common causes of neonatal brain damage. Periventricular white matter damage (periventricular leukomalacia) is the predominant form in premature infants and the most common antecedent of cerebral palsy. Stem cell treatment has proven effective in restoring injured organs and tissues in animal models. The potential of stem cells for self-renewal and differentiation translates into substantial neuroprotection and neuroregeneration in the animal brain, with minimal risks of rejection and side effects. Stem cell treatments described to date have used neural stem cells, embryonic stem cells, mesenchymal stem cells, umbilical cord stem cells, and induced pluripotent stem cells. Most of these treatments are still experimental. In this review, we focus on the efficacy of stem cell therapy in animal models of cerebral palsy, and discuss potential implications for current and future clinical trials.

Mesenchymal stromal cells for tissue-engineered tissue and organ replacements

Mesenchymal stromal cells (MSCs), a rare heterogeneous subset of pluripotent stromal cells that can be easily isolated from different adult tissues, in vitro expanded and differentiated into multiple lineages, are immune privileged and, more important, display immunomodulatory capacities. Because of this, they are the preferred cell source in tissue-engineered replacements, not only in autogeneic conditions, where they do not evoke any immune response, but especially in the setting of allogeneic organ and tissue replacements. However, more preclinical and clinical studies are requested to completely understand MSC's immune biology and possible clinical applications. We herein review the immunogenicity and immunomodulatory properties of MSCs, their possible mechanisms and potential clinical use for tissue-engineered organ and tissue replacement.

Umbilical Cord Blood Banking and Transplantation: A short review

It is more than 20 years since the first cord blood transplant (CBT) was performed, following the realisation that cord blood (CB), which is normally wasted, is rich in progenitor cells and capable of rescuing haematopoiesis. Since then it has been appreciated that CB is rich in stem cells, and has many other features not the least of which is its ability to rescue the transplanted patient without a rigid need for full human lymphocyte antigen (HLA) compatibility. Also it is easily accessible, relatively free from infections and poses no medical risk to the donor. However, the quantity of the stem cells is rather small, thus predominantly restricting its use to children or adults requiring double units. In Oman, we have taken a keen interest in stem cell research and also CBT. We see such activities as an avenue for our patients, for whom a compatible bone marrow (BM) or a peripheral blood donor cannot be found, to have an alternative in the form of CBT. This has encouraged us to establish a national voluntary cord blood bank (CBB) which is a valuable option open to a selected group of patients, as compared to the controversial private CBB. This national CBB will have a better representation of HLA-types common in the region, an improvement on relying on banks in other countries. Considering the need for stem cell transplant/therapy in this country, it is only appropriate that this sort of bank is established to cater for some of these requirements.

Modulation of AP-endonuclease1 levels associated with hepatic cirrhosis in rat model treated with human umbilical cord blood mononuclear stem cells

Oxidative stress in liver cells may contribute to the etiology of hepatic diseases, as in liver cirrhosis. AP-Endonuclease1 (APE1/Ref-1) is essential for cell protection toward oxidative stress by acting as a transcriptional regulator of pro-survival genes and as a redox sensitive protein. The aim of this study was to critically analyze the various parameters governing the success of human umbilical cord blood mononuclear stem cell-based (MNCs) therapy without the use of an immunosuppressant and to investigate for the first time the expression of APE1 during thioacetamide (TAA)-induced cirrhosis and MNCs therapy in a rat model. Umbilical cord blood samples from full-term deliveries were collected. Lethal fulminant hepatic cirrhosis in rats was induced by intraperitoneal injection of thio-acetamide. MNCs were then intrahepatically transplanted. We measured APE1 expression at mRNA and protein levels, mRNA expression of TGF-β, α-SMA, STAP, CTGF, MMP-9 and TIMP-1 in a follow up study. Histopathological and immunohistochemical analyses were performed 10 weeks after intrahepatic injection of the cells. Transdifferentiated cells could be efficiently stained with antihuman hepatocytes. Interestingly, human hepatocyte-specific markers, human albumin, cytokeratin-18 and cytokeratin-19 mRNAs were detected in rat liver after 10 days of MNCs infusion. MNC transplanted by intrahepatic route, could engraft recipient liver, differentiated into functional hepatocytes, and rescued liver failure. Moreover up regulation of APE1 expression confirmed by marked immunohistochemical staining may be involved in MNCs-induced hepatocytes regeneration suggesting that maintaining high level of APE1 has protective effect as pro-survival signal.

New perspectives in stem cell research: beyond embryonic stem cells

Although stem cell research is a rather new field in modern medicine, media soon popularized it. The reason for this hype lies in the potential of stem cells to drastically increase quality of life through repairing aging and diseased organs. Nevertheless, the essence of stem cell research is to understand how tissues are maintained during adult life. In this article, we summarize the various types of stem cells and their differentiation potential in vivo and in vitro. We review current clinical applications of stem cells and highlight problems encountered when going from animal studies to clinical practice. Furthermore, we describe the current state of induced pluripotent stem cell technology and applications for disease modelling and cell replacement therapy.

Insights into the biology of cord blood stem/progenitor cells

OBJECTIVES

To review information on cord blood banking and transplantation with respect to the author's studies, and in context of this field of investigation.

RESULTS

Cord blood transplantation has been successfully used to treat a number of malignant and non-malignant disorders. However, this technique is still associated with limited numbers of cells for transplantation, and with delayed engraftment of neutrophils and platelets. The field of cord blood transplantation will benefit from enhanced and mechanistically based information on haematopoietic stem cell function and potential means to enhance its effectiveness are reviewed. This includes notions concerning possibility of retrieving more cells from the placenta and cord blood, to expand haematopoietic stem cells ex vivo and to increase efficiency of homing and engraftment of these cells. Also discussed are cryopreservation and long-term storage of cord blood haematopoietic and progenitor cells, and new laboratory findings and animal studies for non-haematopoietic uses of cord blood.

Eicosanoid regulation of hematopoiesis and hematopoietic stem and progenitor trafficking

Hematopoietic stem cell (HSC) transplantation is a potentially curative treatment for numerous hematological malignancies. The transplant procedure as performed today takes advantage of HSC trafficking; either egress of HSC from the bone marrow to the peripheral blood, that is, mobilization, for acquisition of the hematopoietic graft, and/or trafficking of HSC from the peripheral blood to bone marrow niches in the recipient patient, that is HSC homing. Numerous studies, many of which are reviewed herein, have defined hematopoietic regulatory mechanisms mediated by the 20-carbon lipid family of eicosanoids, and recent evidence strongly supports a role for eicosanoids in regulation of hematopoietic trafficking, adding a new role whereby eicosanoids regulate hematopoiesis. Short-term exposure of HSC to the eicosanoid prostaglandin E(2) increases CXCR4 receptor expression, migration and in vivo homing of HSC. In contrast, cannabinoids reduce hematopoietic progenitor cell (HPC) CXCR4 expression and induce HPC mobilization when administered in vivo. Leukotrienes have been shown to alter CD34(+) cell adhesion, migration and regulate HSC proliferation, suggesting that eicosanoids have both opposing and complimentary roles in the regulation of hematopoiesis. As numerous FDA approved compounds regulate eicosanoid signaling or biosynthesis, the utility of eicosanoid-based therapeutic strategies to improve hematopoietic transplantation can be rapidly evaluated.

Biological characteristics of stem cells from foetal, cord blood and extraembryonic tissues

Foetal stem cells (FSCs) can be isolated during gestation from many different tissues such as blood, liver and bone marrow as well as from a variety of extraembryonic tissues such as amniotic fluid and placenta. Strong evidence suggests that these cells differ on many biological aspects such as growth kinetics, morphology, immunophenotype, differentiation potential and engraftment capacity in vivo. Despite these differences, FSCs appear to be more primitive and have greater multi-potentiality than their adult counterparts. For example, foetal blood haemopoietic stem cells proliferate more rapidly than those found in cord blood or adult bone marrow. These features have led to FSCs being investigated for pre- and post-natal cell therapy and regenerative medicine applications. The cells have been used in pre-clinical studies to treat a wide range of diseases such as skeletal dysplasia, diaphragmatic hernia and respiratory failure, white matter damage, renal pathologies as well as cancers. Their intermediate state between adult and embryonic stem cells also makes them an ideal candidate for reprogramming to the pluripotent status.