• 1.

  a) T b) T c) F d) T e) F

Neural stem cells are by definition multipotent, and can give rise to the three main types of CNS cells. NSCs will not give rise to microglia. Microglia are not derived from the CNS, they have mesodermal origin and migrate into the CNS during development. Self-renewal is by definition a key feature of all stem cells, the ability to divide and multiply the number of stem cells. Differentiation is a process involving intrinsic and extrinsic cues. In the adult central nervous system, the milieu with gradients of morphogens and extracellular molecules is not identical to the embryonic central nervous system and the control of differentiation of NSC is not present. A possible alternative may be to transplant neural progenitor cells of various specifications, with a limited capacity to differentiate only into the appropriate neuron.

• 2.

  a) T b) F c) T d) F e) F

The symptoms of neurodegenerative diseases occur when a considerable number of neurons have already succumbed to degeneration. Thus in the early phase of neurodegeneration, the patient is typically not aware of having the disease, and is therefore not known to the health care organization involved in the clinical trial. As described, the major loss of neurons occurs in the stage of disease before diagnosis is made. The risk of causing negative side effects has been a major concern for clinical trials using cell types for the first time in human patients. As a consequence, patients have been recruited in a late stage of the disease when the clinical situation is already so bad that there is little to lose from an uncertain outcome. In the classical neurodegenerative diseases, not including MS, inflammation is not the major cause of neuronal damage. Although inflammation may add to the main pathophysiological processes, many types of stem and progenitor cells actually have the capacity to reduce inflammation.

• 3.

  a) F b) F c) F d) F e) T

There are no reports of transplanted mesencephalic tissue giving rise to either tumors or infections. Embryonic/fetal CNS tissue, as well as stem and progenitor cells derived from this tissue, are not tumorigenic probably due to intact contact inhibition. Strict routines for the dissection of embryonic/fetal tissue with extensive rinsing of the tissue apparently are sufficient to eliminate the risk of infections. The injections of tissue pieces cause minimal damage, and the target region is much larger than the parts directly affected by the injections. Dyskinesia has appeared in transplanted patients. Although there may be alternative explanations for this side-effect, on-going trials can answer the question if this is a consequence of the transplantation and also if dyskinesia can be avoided by more standardized procedures before, during and after the transplantation.

• 4.

  a) T b) F c) F d) T e) F

The application of human neural cell therapy and utilization of residual human tissues raises ethical concerns, and is therefore strictly regulated to protect both donor and host in experimental and clinical applications. Human neural cell therapy application in the laboratory or clinic involves ethical concerns that require adherence to ethical guidelines, study protocols and procedures approved by regulatory authorities including the regional human ethical committee and informed consent from tissue donors as well as potential host recipients.

• 5.

  a) F b) T c) F d) T e) T

Intraperitoneal drug administration is mainly used in experimental animal models. It is rarely used in clinical newborn medicine, but would be feasible together with adequate analgesia. Intravenous access is routinely established in the newborn infant. Intra-tracheal administration will require intubation, an invasive procedure performed after adequate pre-medication of analgesia and sedation, thus it is not too painful. Engraftment is limited in experimental models of BPD, regardless of whether the cells are given locally or systemically. However, the only study to date directly comparing routes of administration, (Chang et al.), revealed that intra-tracheal administration indeed did produce more effective engraftment associated with greater reduction in hyperoxia-induced impaired alveolarization compared to systemic (intraperitoneal) administration. It is true that surfactant is delivered by intra-tracheal administration. However, surfactant treatment is most often applied during the first 1-2 days of life. The optimal timing of cell-based therapy to prevent or treat BPD is yet to be determined. Although an appealing idea, there is no evidence today suggesting that stem cells can be given in conjunction with surfactant treatment to prevent BPD. Cells will migrate towards injured lung both after local and systemic administration. The first passage effect may very well result in sequestering of the majority of cells in the lung following intravenous administration, but that remains to be proven. Again, the only study to date directly comparing local and systemic administration (Chang et al.) implies that transplanted cells to a greater extent are found in the injured lung following intra-tracheal administration. There are 7 clinical trials of stem cell therapy for BPD currently registered, all but one using the intra-tracheal route of administration and it is correct that the only clinical study yet to publish results used the same route. Therefore, it can be said that, until further evidence is available, safety and feasibility have only been established for intra-tracheal administration of cell therapy for treatment of BPD.

• 6.

  a) F b) F c) F d) F e) T

Although hypoxia contributes to the causative cascade of factors contributing to brain injury in both term and preterm newborns, term brain injury usually results from acute, profound hypoxia / asphyxia, whereas preterm brain injury is often subacute or chronic. Also, in preterm infants intraventricular hemorrhage, secondary to immature brain structure and vascular auto-regulation, is a major underlying cause of brain injury. Because the primary insult leading to brain damage differs between term and preterm infants the injury pattern also differs, affecting mainly deep grey matter, basal ganglia, the hippocampus and neighboring matter in term infants, whereas in preterm infants injury it is often related to a prior hemorrhage leading to periventricular areas being more affected, as in cystic periventricular leucomalacia, or more diffusely localized to the white matter. Rats and mice, often used in term hypoxic-ischemia models, have a much lower white/grey matter ratio than humans making induction of white matter injury as seen in preterm infants problematic. Injury induced in rabbits, sheep, cats and dogs have a morphological appearance more similar to that of human preterm brain. Post-hemorrhagic hydrocephalus is a complication mainly seen after severe intra-ventricular bleedings in preterm infants, but is very rare in term infants. The main aim of a cell-based strategy in both term and preterm infants would be neuroprotection, meaning prevention of long-term neurological impairment and promotion of normal neurodevelopment. A common ground for all cellular induced neurological repair processes appears to be inflammatory actions. Umbilical cord blood cells, the most widely used cells in models of both preterm and term brain injury, have various paracrine functions inducing secretion of trophic factors, such as BDNF, VEGF, fibroblast and epidermal growth factors. By promoting neuronal growth, angiogenesis, synaptogenesis and decreasing cellular apoptosis, these factors contribute to neuroprotection in both term and preterm infants.

• 7.

  a) F b) T c) T d) T e) F

Fetal micro-chimerism has been found in higher levels in women with SLE, but maternal micro-chimerism has not been reported. MMc has been found by two groups in the livers of infants with biliary atresia. Two groups have reported increased MMc in the muscle biopsies of children with JDM, at higher levels than those with other muscle diseases. One of those groups also reported high levels of MMc in peripheral neutrophils from JDM patients. MMc has been found at higher levels in men with systemic sclerosis. MMc has not been reported in JIA.

• 8.

  a) F b) F c) T d) T e) T

Although IL-2 is important for T cell activation, it has not been reported to be involved in maternal-fetal tolerance. IL-1 made by monocytes is an important effector of auto-inflammatory diseases but has not been implicated in maternal-fetal tolerance. IL-10 made by a fraction of regulatory T cells is important during pregnancy, and has also been shown to be an important effector of T cell tolerance induced by maternal antigens in adult subjects. Regulatory T cells producing TGF have been demonstrated in fetal lymph nodes. In addition, these cells have been shown to persist in the peripheral blood to maintain anti-maternal tolerance in the transplantation setting. PD1 expressed in the placenta and on regulatory T cells inhibits T cell activation. Loss of PD1 has been associated with autoimmune diseases and fetal loss.

• 9.

  a) T b) F c) T d) T e) F

The primary cause of morbidity and mortality related to postnatal hematopoietic stem cell transplantation is host immune response against allogeneic antigen and the required immunosuppression and myelo-ablation to achieve tolerance of the graft. The potential for avoidance of this response by taking advantage of the normal developmental mechanisms of “self tolerance” is a compelling rationale favoring fetal over postnatal stem cell transplantation and the most important of the potential biologic advantages supporting IUHCT. Fetal hematopoietic stem cell biology is not favorable for adult derived HSC and competition from host hematopoiesis and this represents the most important barrier to donor cell engraftment. Fetal HSC are more proliferative, more numerous, and are developmentally primed for inductive factors for migration and engraftment during fetal development. Thus, a major emphasis of research related to IUHCT has been directed toward improving the competitive balance between adult and fetal cells. Normal thymic mechanisms for “self” tolerance and the prevention of autoimmune disease are also the primary mechanisms of fetal tolerance to transplanted allogeneic cells. In experimental IUHCT, both clonal deletion and generation of T-regulatory cells play a role in donor specific tolerance of the graft. The regulatory limb of this process is less well defined and the developmental balance of effector and regulatory mechanisms may ultimately determine the limits of the immunologic window of opportunity for IUHCT. Recent studies in the murine model have implicated the maternal immune response to donor antigen in the development of an adaptive immune response and loss of engraftment after IUHCT. Whether this same phenomenon will occur clinically is unknown but until further information is available from pre-clinical models, the use of maternal cells is preferable.

The rationale for IUHCT extends far beyond the rare stem cell based disorders that effect fetal well-being. The beta-hemoglobinopathies for instance have normal fetal hematopoiesis and only become manifest after beta-hemoglobin production occurs after birth.

• 10.

  a) F b) T c) F d) T e) F

Non-viral based DNA delivery methods are relatively inefficient compared to viral vector based DNA delivery in essentially all circumstances including fetal gene therapy strategies. While attractive from a safety perspective, the low efficiency profile has limited in vivo applications of the non-viral methods. Developmental events have enormous impact on the success or failure of in utero gene therapy strategies. The primary rationale for in utero gene therapy is related to the increased accessibility of target stem cell populations relative to postnatal life. The opportunities to access these populations directly relate to the developmental status of organ development, frequency of stem cell populations in tissues, and anatomic exposure as it relates to mode of administration of the vector (intra-amniotic vs. intravascular for instance). The small size of the fetus is actually a major advantage for in utero gene therapy from the perspectives of vector particle to cell number ratio and amount of vector required. These advantages outweigh the technical limitations to delivery of vector into specific compartments which can largely be overcome with modern ultrasound and delivery technology. The genetic manipulation of the early gestational fetus is associated with risks that are unique to the fetus and potentially an increased likelihood of the occurrence of risks observed in postnatal gene therapy. Risks that are unique to the fetus include off target developmental effects of for instance growth or transcription factor expression. There is likely an increased risk of germ line transduction and insertional mutagenesis in the fetus, both also concerns of postnatal gene therapy. The recent development of gene editing techniques are likely to revolutionize the field of gene therapy and will have a major impact on future gene therapy strategies in the fetus. These include the potential to utilize gene edited autologous cells (amniotic stem cells for instance) for correction of genetic disorders and the potential for in situ gene editing in disorders where only a small percentage of corrected stem cells can prevent the disorder. For instance disorders where there is a requirement for only a small number of functionally corrected cells to prevent the defect (e.g. hyper IgM Syndrome), or in circumstances of a competitive advantage for corrected cells, an expansion of the corrected cells to therapeutic numbers (e.g. SCID, Muscular dystrophy).

• 11.

  a) T b) T c) T d) T e) T

Pluripotent cells have the capacity to differentiate into any lineages of the three germ layers and form teratomas in vivo; there are no “safe” iPS cells.

• 12.

  a) T b) T c) T d) T e) F

Fetal cells isolated before birth have a primitive phenotype and still express telomerase, hence have longer telomeres than their adult counterparts. They can also be used to treat babies before birth or after birth. Cells from younger developmental age are usually easier to reprogram because they express lower levels of Ink4/arf.

• 13.

  a) T b) T c) T d) T e) T

The use of iPS cells for cell therapy requires in vitro differentiation into a specific lineage and removal of cells that have not differentiated before transplantation. However, this requires robust differentiation protocols and the capacity of the iPS cells to repress the pluripotency network completely to avoid aberrant differentiation. Finally, the capacity of an iPS cells to adopt a specific lineage is dependent on the tissue of origin (epigenetic memory).

• 14.

  a) F b) F c) T d) F e) F

The most important gene is OCT4, in the absence of which cells fail to adopt a pluripotent phenotype.

• 15.

  a) F b) F c) T d) T e) F

Human embryonic stem cells are used for age-related macular degeneration and spinal cord injury. The others are still under earlier development.

• 16.

  a) F b) T c) T d) F e) F

There are no longer any embryonic stem cells in fetuses that have implanted.

• 17.

  a) F b) T c) F d) F e) F

No serum or tissue-derived components need to be used today.

• 18.

  a) T b) T c) T d) F e) F

The placenta is a reservoir of stem cells, with specialized populations such as mesenchymal, hematopoietic and trophoblastic stem cells. Placental stem cells with higher proliferative rates than cells from fetal and adult tissues have been more widely studied and include the human amniotic epithelial cells (hAEC), human amniotic mesenchymal stromal cells (hAMSC) and chorionic mesenchymal stromal cells (hCMSC). The human placenta can be considered an alternative source of mesenchymal stem cells that bypass the difficulties that arise from sources like the bone marrow, umbilical cord, adipose tissue and peripheral blood. It is possible to isolate mesenchymal and hematopoietic cell lineages from the chorion, allantois, amniotic and yolk sac. At present, there are a number of clinical trials that have investigated the therapeutic use of placenta-derived cells in a variety of diseases, such as Type 2 diabetes, malignant and non-malignant disorders, severe aplastic anaemia, pulmonary fibrosis, haematological malignancies, Crohn’s disease, and ischaemic stroke. The placenta represents a reservoir of a range of progenitor, stem and epithelial cells that have been shown to differentiate into various types including adipogenic, osteogenic, myogenic, hepatogenic, cardiac, pancreatic, endothelial, pulmonary, and neurogenic lineages.

• 19.

  a) T b) F c) F d) F e) T

Pluripotent embryonic stem cells originate as inner mass cells within a blastocyst. At day 9 post-conception the inner cell mass induces the formation of the epiblast and hypoblast that subsequently give rise to the amniotic cavity and the yolk sac. The process of gastrulation enables the bilaminar disc to differentiate into the three germ layers (ectoderm, mesoderm and endoderm) which is then followed by organogenesis. According to some research studies, the placental stem cells express pluripotency markers such as SSEA3, SSEA4, OCT4, NANOG, TRA-1-60 and TRA-1-81. Placental stem cells have been shown to possess greater expansion capacity, generation doubling time and proliferation rates than adult MSCs and do not form teratomas which characterizes the ES and iPS cell population. The absence of rejection of placental tissues and placental-derived meshes that have been used to treat skin burns and ulcers suggests that there is reduced immunogenicity of placental-derived amniotic epithelial cells. The basis of the ethical considerations upon which embryonic stem cells was focused on their isolation from developing blastocysts that could potentially develop into an embryo. However, the full-term placenta can be collected after birth since as it is considered medical waste; thus it does not elicit any major ethical concerns.

• 20.

  a) T b) T c) T d) F e) F

Bone marrow-derived MSC and human placenta-derived MSC appear to have similar patterns of adhesion molecules [β1-integrins CD29, CD44, CD54, E-cadherin, CD166, CD49, integrin a11, and chemokine receptor displays (CCR1, CCR3, CXCR3, CXCR4 and CXCR6), including absence of selectin and fucosyltransferase expression. Private companies have bio-banked placenta stem cells since 2012 in the US under GMP conditions. hAMSC and hCMSC both express limited levels of HLA-A,B,C suggesting an immune-privileged profile and their remarkable immunosuppressive properties contribute to their usage in a transplantation setting. Placental mesenchymal stromal cells are derived from the extraembryonic mesoderm and show tri-lineage differentiation potential, maintain long telomeres, express markers associated with pluripotency such as Oct4 and SSEA-3 (however the expression levels of SSEA-4 are controversial) and have immune-privileged characteristics, augmented proliferative rates and high clono-genicity. However, the properties of the MSCs vary according to the developmental stage and gestation of the placental source and chorionic villi.

• 21.

  a) F b) F c) T d) T e) T

Placental mesenchymal stromal cells are derived from the extraembryonic mesoderm and show tri-lineage differentiation potential, maintain long telomeres, express markers associated with pluripotency such as Oct4 and SSEA-3 (however the expression levels of SSEA-4 are controversial) and have immune-privileged characteristics, augmented proliferative rates and high clono-genicity.

• 22.

  a) F b) F c) F d) T e) T

Placental-derived stem cell banking for clinical purposes can use both a public- universal-donor model and an autologous-source model where pregnant women can choose to privately store their baby’s own placental cells. There are high costs associated with bio-banking placental stem cells due to the need for specialized medical trainees to use standardized isolation methods, import of biobanks using quality and assurance system controls and the high costs of storage of placental stem cells. To ensure high quality results, the establishment of biobanks for placenta cells that are considered medicinal products relies on regional regulatory frameworks, the nature of storage (autologous, familial, allogeneic usage) and public or private funding that may subsequently affect the standards governing the harvesting and processing protocols. Women are excluded if they have a history of specific medical conditions or a sexual or drug history that makes them vulnerable to infection with HIV, hepatitis B or C. Bio-banked human placenta-derived stem cells could be used in the short term for drug screening on cells of human origin and in autologous grafting and HLA compatible allogeneic stem cell transplantations.

• 23.

  a) T b) T c) T d) T e) T

The placenta represents a reservoir of a range of progenitor, stem and epithelial cells that have been shown to differentiate into various types including adipogenic, osteogenic, myogenic, hepatogenic, cardiac, pancreatic, endothelial, pulmonary, and neurogenic lineages.

• 24.

  a) F b) F c) T d) T e) F

AFSC, isolated using CD117 expression as a cell surface marker, are thought to be broadly multipotent. This means that they are able (under appropriate culture conditions) to differentiate to all embryonic germ layer lineages (endoderm: origin of most of the gastrointestinal and respiratory tissues, as well as some endocrine tissues; mesoderm: origin of bone, cartilage, fat, muscle; ectoderm: origin of skin, central and peripheral nervous system, hair and nails), but do not form teratomas when injected in immunocompromised mice, and are unable to generate these germ layer lineages when injected into a blastocyst. The latter two points are essential pre-requisites for pluripotency, and are characteristics of both embryonic stem cells and induced pluripotent stem cells. The fact that AFSC have the ability to differentiate into all embryonic germ lineages but have low tumorigenic potential makes them ideal candidates for regenerative medicine applications. The cells present in the amniotic fluid are heterogeneous. Both the cellularity of the amniotic fluid as well as the various cell types that can be found in it vary with gestational age. The majority of the cells within the amniotic fluid are either differentiated cells (e.g. epithelioid, fibroblastic) or dying/dead cells (proportion of dead cells increases as pregnancy progresses). AFSC represent less than 1% of the total live cells (this proportion is also variable, and is affected by gestational age), and as a result are relatively rare within the variable cell populations found in the amniotic fluid. Culture conditions are key in order to maintain the broadly multipotent potential of AFSC. Cells found in an amniocentesis sample are initially plated in a non-tissue culture treated dish (Petri dish) with media containing high levels of serum (15%). Cells are allowed to attach for approximately 5-7 days (a small portion of plated cells attach, forming distinct colonies). The attached cells are then selected for CD117 (using magnetic beads or flow cytometry) and are re-plated in Petri dishes. Cell growth is quick (doubling time approximately 36 hours) and care should be taken to prevent cells from becoming over-confluent. Cell should be passaged to maintain confluence of 60% of less. Culture in non-tissue culture treated plates in high serum conditions, and maintenance of confluence to 60% or less are essential for maintaining the cellular and differentiation characteristics of AFSC. Induced pluripotent stem cells (iPSC) with potential for therapeutic applications can be derived from somatic cells via ectopic expression (using lentiviral vectors) of a set of limited and defined transcription factors (“Yamanaka factors”: Oct4, c-Myc, KLF4, Sox2). However, due to risks of random integration of the reprogramming transgenes into the host genome, the low efficiency of the process, and the potential risk of virally induced tumorigenicity, alternative methods have been developed to iPSC using non-integrating systems (with limited success). CD117 positive AFSC (first or second trimester) can be fully reprogrammed to pluripotency by culture in standard embryonic stem cell conditions with the addition of the histone deacetylase inhibitor valproic acid (FDA approved anticonvulsant). Following exposure to VPA (1mM), AFSC become capable of forming teratomas when injected into immunocompromised mice, and share >80% transcriptome identity with embryonic stem cells. In the animal model of necrotising enterocolitis (rat), administration of AFSC in the peritoneal cavity result in homing of the AFSC to the injured intestine and resulted in improved clinical status and survival via a COX-2-mediated mechanism. In this case, transplanted AFSC did not proliferate, differentiate and replace damaged intestinal cells, but the beneficial effect was due to a paracrine effect. In the case of muscular dystrophy, systemic administration of fresh or expanded AFSC enhanced muscle strength, improved survival rate and restored muscle phenotype in comparison to untreated animals. Transplanted AFSC were found to have replaced up to 50% of the muscle fibres of the host, with evidence of engraftment in the myogenic stem cell niche. This is consistent with AFSC being able to differentiate towards a myogenic lineage, proliferate and participate in de novo muscle generation resulting in improvement of disease phenotype.

• 25.

  a) T b) F c) F d) T e) T

Isolation of AFMSC depends on culturing the cells in MSC culture conditions. Cell from the amniotic fluid are seeded in tissue-culture treated dishes and are cultured in high serum conditions (20%) in the presence of basic fibroblast growth factor. There is no selection of the cells based on expression of CD117 on their cell surface. This is in contrast to the selection and culture conditions used for AFSC.

AFMSC are considered to be multipotent with mesodermal potential. As a result, under the appropriate culture conditions, they have the potential to differentiate in the adipogenic, chondrogenic and osteogenic routes. This is one of the defining characteristics of all MSC including AFMSC. AFMSC cannot differentiate to hepatocytes and neurons as these have endodermal and ectodermal origin respectively. In order to achieve endodermal and ectodermal differentiation, AFMSC need to be reprogrammed to iPSC; this is a key difference between AFSC and AFMSC. MSC were first identified in the bone marrow, but MSC have also been found in multiple other sites of the human body including skeletal muscle, dental pulp, umbilical cord blood, adipose tissue, synovial membrane and tendon. The discovery of a lot of MSC-like cells and an associated variability in nomenclature led the International Society for Cellular Therapy (ISCT) to suggest the term multipotent mesenchymal stromal cells, and publish a set of minimal criteria that need to be fulfilled for a cell to be labelled as such. One of the key criteria is that >95% of the population must express CD105, CD73 and CD90, and >98% of the population must lack haematopoietic markers including CD34 and CD45. As a result “true” AFMSC express CD105, CD73 and CD90, but do not express CD34 and CD45. In similarity to what has been observed with MSC from other sources, AFMSC have beneficial effects against hypoxic and traumatic injury in the central and peripheral nervous systems. The salutary effects of AFMSC administration in this setting are mediated by homing to the site of injury, and either differentiation to glial cells (non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons; astrocytes in the central nervous system and Schwann cells in the peripheral nervous system), or release (and paracrine activity) of trophic factors that stimulate the activity of host glial cells. AFMSC have not been shown to differentiate into neurons in this setting. In the setting of tissue engineering, appropriate scaffolds (natural or synthetic) are combined with appropriate cell types to generate a tissue or organ of interest. Scaffolds can be pre-seeded with cells in the laboratory (and then placed in a bioreactor to promote growth and differentiation), or can be transplanted directly relying on migration of host cells to the scaffold for repopulation and remodelling. Given the significant chondrogenic and osteogenic potential of AFMSC, they have been used in animal models for tracheal and bone tissue engineering. In studies on the trachea, pre-seeding of scaffolds with AFMSC resulted in improved epithelialisation, higher levels of elastin and reduced incidence of stenosis following transplantation. In studies on bone tissue engineering, pre-seeding of scaffolds with AFMSC resulted in improved mineralisation and remodelling.

• 26.

  a) F b) T c) F d) F e) T

Although WJ-MSC and AF-MSC express embryonic stem cell markers, they are not tumorigenic in contrast to pluripotent embryonic stem cells. Theoretically, AF-MSC could be collected in all three trimesters of pregnancy by amniocentesis. At term AF-MSC could be obtained after delivery by caesarean section. WJ-MSC can be isolated from the umbilical cord after vaginal delivery or caesarean section. WJ-MSC and AF-MSC do not express MHC class II molecules making them less immunogenic and, thus, promising candidates for stem cell therapy in allogeneic transplantations. If the MHC molecules of host and graft did not match, the MHC molecules of the graft would act themselves as antigens and cause transplant rejection. Adult MSC, such as BM-MSC, have been initially shown to differentiate into cells of the mesodermal lineage. However, the perinatal WJ-MSC and AF-MSC can also be induced into cells of the ectoderm (e.g. neuroglial cells, epidermal cells) and endoderm (e.g. hepatocytes, insulin-producing cells) in vitro.

• 27.

  a) F b) F c) T d) T e) F

The opposite is the case. An inflammatory environment triggers a shift from a balanced to an immunosuppressive cell type in WJ-MSC and AF-MSC. The immunomodulation of WJ-MSC and AF-MSC works through cell contact and paracrine mechanisms. WJ-MSC and AF-MSC secrete immunosuppressive factors, such as IL-6, VEGF and GRO. Unstimulated AF-MSC have been shown to block T cell replication to a certain degree, that is, however, significantly elevated when AF-MSC were primed by the inflammatory cytokines TNF-α and IFN-γ. WJ-MSC and AF-MSC have been suggested to have similar immunomodulatory properties as BM-MSC. However, the priming with PBMC or IL-1β triggers an increased secretion of immunomodulatory cytokines relative to BM-MSC.

• 28.

  a) T b) F c) F d) F e) T

Right common carotid artery ligation, followed by hypoxia for 3 hours successfully resulted in frontal cortex damage. Early (24 hours post damage) WJ-MSC administration was more effective. However, the route of cell delivery had no influence on the behavioural outcome. The opposite was the case – astrogliosis was lower after intra-venous application of WJ-MSC. 21% of transplanted WJ-MSC differentiated into neuronal cells. GM1 has previously been shown to have therapeutic effects on ischemic stroke or trauma. The application of GM1 even boosted the beneficial impact of WJ-MSC.

• 29.

  a) F b) F c) F d) F e) T

Freezing of WJ-MSC resulted in changes of proteomic quality and quantity. After large scale expansion, AF-MSC lost their differentiation potential entirely. WJ-MSC isolated from umbilical cords of pre-eclamptic women displayed significantly more oligodendroglial and neuronal markers than the cells from gestational age matched controls, suggesting that pre-eclampsia might enhance the neuroglial differentiation potential of WJ-MSC. Unfortunately, it has been recently suggested that AF might not be the ideal stem cell source, as the cells in the AF are very heterogeneous. Chitosan scaffolds for WJ-MSC, further complemented with BDNF, have been designed. The scaffolds steadily released BDNF and induced neural stem cells to differentiate into neurons.

• 30.

  a) T b) T c) T d) T e) F

MSC are fibroblastic stromal cells, and this type of cell always adhere to plastic during normal conditions in vitro. There is no specific marker for MSC, and consequently a panel of selected known markers should simultaneously be expressed on the surface of the cells. MSC are non-hematopoietic and endothelial cells and should not express any markers associated to these lineages as well as no co-stimulatory molecules. MSC are multipotent stem cells and should minimally be able to differentiate into the mesodermal lineages bone, cartilage and fat. The ability to differentiate in other cell lines is the definition of pluripotent cells and while possible under certain conditions it is not a pre-requisite.