Stem Cell Therapy as a Treatment for Osteogenesis Imperfecta

PURPOSE OF REVIEW

Osteogenesis imperfecta (OI) is a chronic disease with few treatment options available. The purpose of this review is to provide an overview on treating OI with mesenchymal stem cells (MSC).

RECENT FINDINGS

Off-the-shelf MSC have a good safety profile and exhibit multilineage differentiation potential and a low immunogenic profile and are easy to manufacture. Their ability to migrate, engraft, and differentiate into bone cells, and also to act via paracrine effects on the recipient's tissues, makes MSC candidates as a clinical therapy for OI. Due to their high osteogenic potency, fetal MSC offer an even higher therapeutic potential in OI compared with MSC derived from adult sources. Preclinical and initial clinical data support the use of MSC in treating OI. The characteristics of MSC make them of great interest in treating OI. MSC may be safely transplanted via intravenous administration and show potential positive clinical effects.

Vitamin C- and Valproic Acid-Induced Fetal RPE Stem-like Cells Recover Retinal Degeneration via Regulating SOX2

Retinal pigment epithelial (RPE) cell replacement therapy has provided promising outcomes in the treatment of retinal degenerative diseases (RDDs), but the resulting limited visual improvement has raised questions about graft survival and differentiation. Through combined treatment with vitamin C and valproic acid (together, VV), we activated human fetal RPE (fRPE) cells to become highly proliferative fetal RPE stem-like cells (fRPESCs). In this study, we report that SOX2 (SRY-box 2) activation contributed to mesenchymal-epithelial transition and elevated the retinal progenitor and mesenchymal stromal markers expressions of fRPESCs. These fRPESCs could differentiate into RPE cells, rod photoreceptors, and mesenchymal lineage progenies under defined conditions. Finally, fRPESCs were transplanted into the subretinal space of an RDD mouse model, and a photoreceptor rescue benefit was demonstrated. The RPE and rod photoreceptor differentiation of transplanted fRPESCs may account for the neural retinal recovery. This study establishes fRPESCs as a highly proliferative, multi-lineage differentiation potential (including RPE, rod photoreceptor, and mesenchymal lineage differentiation), mesenchymal-to-epithelial-transitioned retinal stem-like cell source for cell-based therapy of RDDs.

Yiguanjian decoction enhances fetal liver stem/progenitor cell-mediated repair of liver cirrhosis through regulation of macrophage activation state

AIM

To investigate whether Yiguanjian decoction (YGJ) has an anti-liver cirrhotic effect and whether it regulates hepatic stem cell differentiation.

METHODS

A rat model of liver cirrhosis was established via subcutaneous injection of carbon tetrachloride (CCl₄) for 8 wk. From the beginning of the ninth week, the rats received 2-acetylaminofluorene (2-AAF) by oral gavage and a DLK-1⁺ fetal liver stem/progenitor cell (FLSPC) transplant or an FLSPC transplant in combination with YGJ treatment for 4 wk. In vitro, lipopolysaccharide (LPS)-activated macrophages were co-cultured with WB-F344 cells, and the differentiation of WB-F344 cells was observed in the presence and absence of YGJ treatment.

RESULTS

FLSPC transplantation improved liver function and histopathology, and inhibited the activation of the non-canonical Wnt signaling pathway, while activating the canonical Wnt signaling pathway. YGJ enhanced the therapeutic effects of FLSPCs and also promoted the liver regeneration differentiation of FLSPCs into hepatocytes. In vitro, LPS-activated macrophages promoted the differentiation of WB-F344 cells into myofibroblasts, and the canonical Wnt signaling was inhibited while the non-canonical Wnt signaling was activated in WB-F344 cells. YGJ suppressed the activation of macrophages and then inhibited non-canonical Wnt signaling and promoted canonical Wnt signaling.

CONCLUSION

YGJ enhances FLSPC-mediated repair of liver cirrhosis through regulation of macrophage activation state, and YGJ in combination with stem cell transplantation may be a suitable treatment for end-stage liver cirrhosis.

The Therapeutic Effectiveness of Delayed Fetal Spinal Cord Tissue Transplantation on Respiratory Function Following Mid-Cervical Spinal Cord Injury

Respiratory impairment due to damage of the spinal respiratory motoneurons and interruption of the descending drives from brainstem premotor neurons to spinal respiratory motoneurons is the leading cause of morbidity and mortality following cervical spinal cord injury. The present study was designed to evaluate the therapeutic effectiveness of delayed transplantation of fetal spinal cord (FSC) tissue on respiratory function in rats with mid-cervical spinal cord injury. Embryonic day-14 rat FSC tissue was transplanted into a C4 spinal cord hemilesion cavity in adult male rats at 1 week postinjury. The histological results showed that FSC-derived grafts can survive, fill the lesion cavity, and differentiate into neurons and astrocytes at 8 weeks post-transplantation. Some FSC-derived graft neurons exhibited specific neurochemical markers of neurotransmitter (e.g., serotonin, noradrenalin, or acetylcholine). Moreover, a robust expression of glutamatergic and γ-aminobutyric acid-ergic fibers was observed within FSC-derived grafts. Retrograde tracing results indicated that there was a connection between FSC-derived grafts and host phrenic nucleus. Neurophysiological recording of the phrenic nerve demonstrated that phrenic burst amplitude ipsilateral to the lesion was significantly greater in injured animals that received FSC transplantation than in those that received buffer transplantation under high respiratory drives. These results suggest that delayed FSC transplantation may have the potential to repair the injured spinal cord and promote respiratory functional recovery after mid-cervical spinal cord injury.

Leptin Level in Patients with Type 2 Diabetes Mellitus after Fetal Pancreatic Stem Cell Transplant

OBJECTIVES

We aimed to determine leptin level in patients with type 2 diabetes mellitus after fetal pancreatic stem cell transplant.

MATERIALS AND METHODS

We examined 14 patients (aged 43-63 years old) with type 2 diabetes mellitus, which we subsequently divided into 2 groups and examined. Group 1 comprised 8 patients who received fetal pancreatic stem cell transplant (cells were 16-18 wk gestation) performed by intravenous infusion; group 2 comprised 6 patients in the control group who were on hypoglycemic tablet therapy or insulin therapy. The quantity of fetal stem cells infused was 5 to 6 × 106. We analyzed leptin and C-peptide levels in patients both before and 3 months after the fetal pancreatic stem cell transplant procedure.

RESULTS

In patients with type 2 diabetes mellitus, fetal pancreatic stem cell transplant led to a significant increase in leptin levels, from 11.01 ng/mL to 16.29 ng/mL, after 3 months (P < .05).

CONCLUSIONS

Leptin level increase significantly within 3 months after fetal pancreatic stem cell transplant in patients with type 2 diabetes mellitus.

Allogeneic fetal stem cell transplantation to child with psychomotor retardation – A case report

INTRODUCTION

The consequences of autologous and allogeneic stem cell transplantation (stem cells of hematopoiesis), applied in adults and children suffering from leukemia or some other malignant disease, are well-known and sufficiently recognizable in pediatric clinical practice regardless of the indication for the treatment. However, the efficacy of fetal stem cell transplantation is unrecognizable when the indications are psychomotor retardation and epilepsy.

CASE OUTLINE

With the exception of neurological psychiatric problems, a boy aged 9.5 years was in good general health before transplantation with allogeneic fetal stem cells. The main aim of allogeneic fetal stem cell transplantation was treatment of psychomotor retardation and epilepsy. After 13 months of treatment, he was admitted to hospital in a very serious, life-threatening condition due to sepsis and severe pleuropneumonia. The humoral immunity in the boy was adequate, unlike cellular immunity. The immune imbalance in terms of predominance of T-suppressor lymphocytes contributes to delayed and late development of sepsis and severe pleuropneumonia. The boy still shows the same severity of psychomotor retardation, dyslalia, epilepsy, strabismus and amblyopia.

CONCLUSION

Implementation of fetal stem cell therapy for unconfirmed indications abuses the therapeutic approach, harms patients, misleads parents, and brings financial harm to the healthcare system of any country, including Serbia.

Fetal Hematopoietic Stem Cell Transplantation Fails to Fully Regenerate the B-Lymphocyte Compartment

B cells are key components of cellular and humoral immunity and, like all lymphocytes, are thought to originate and renew from hematopoietic stem cells (HSCs). However, our recent single-HSC transfer studies demonstrate that adult bone marrow HSCs do not regenerate B-1a, a subset of tissue B cells required for protection against pneumonia, influenza, and other infections. Since B-1a are regenerated by transfers of fetal liver, the question arises as to whether B-1a derive from fetal, but not adult, HSCs. Here we show that, similar to adult HSCs, fetal HSCs selectively fail to regenerate B-1a. We also show that, in humanized mice, human fetal liver regenerates tissue B cells that are phenotypically similar to murine B-1a, raising the question of whether human HSC transplantation, the mainstay of such models, is sufficient to regenerate human B-1a. Thus, our studies overtly challenge the current paradigm that HSCs give rise to all components of the immune system.

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Purified LT-HSC transplantation fails to fully regenerate the murine immune system

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LT-HSC transplants selectively fail to regenerate B-1a cells

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LT-HSC transplantation does not regenerate VH11-encoded natural antibodies

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Human fetal liver regenerate peritoneal B cells that resemble murine B-1a

Human Foetal Mesenchymal Stem Cells

Finding suitable cell sources is one of the main challenges in regenerative medicine. In addition to improving the dysfunctional tissue requiring reconstruction, low immunogenicity is beneficial. Mesenchymal stem cells (MSCs) are immune-privileged multipotent stromal cells that can easily multiply and differentiate along many lineages with a minimal oncogenic risk. MSCs derived from foetal tissues present characteristics that suggest an even stronger cell therapeutic potential in comparison to adult MSCs. Due to these characteristics, they have been and are currently being tested in clinical trials for a diverse variety of disorders.

Effect of osteopontin in regulating bone marrow mesenchymal stem cell treatment of skin wounds in diabetic mice

BACKGROUND

We aimed to investigate the role of osteopontin in regulating mesenchymal stem cells transplanted to promote wound healing in diabetic mice.

METHODS

The mesenchymal stem cells of osteopontin knock-out (KO) and wild-type (WT) mice were isolated separately for in vitro culture and characterization. A skin wound on the back of mice was established by skin punching. In 27 osteopontin KO male mice, induced diabetes mellitus was via intraperitoneal injection of streptozotocin. 9 normal mice were used as controls. The mice were divided into four groups and injected with Dulbecco's modified Eagle's medium (DMEM) or mesenchymal stem cells via the tail vein: A (diabetic mice injected with DMEM), B (diabetic mice injected with osteopontin KO mesenchymal stem cells), C (diabetic mice injected with WT mesenchymal stem cells), D (normal mice injected with DMEM). The healing times and closure rates of skin wounds were recorded. The microvessel density of healing wounds was measured, and the localized expression of osteopontin was identified by western blotting and immunohistochemistry. The migration of mesenchymal stem cells was observed on normal mice with skin wound injected with mesenchymal stem cells of C57BL6~GFP transgenic mice, which show green fluorescent under UV light.

RESULTS

Compared with normal mice, the healing time of wounds in the mice with diabetes and osteopontin KO was significantly prolonged (p < 0.01). After transplanting osteopontin KO mesenchymal stem cells, the healing time was slightly shorter. Meanwhile, the healing time was significantly shorter after transplanted with WT mesenchymal stem cells and more significant neovascularization at healing wounds (p < 0.05). The expression of osteopontin in local healing wounds after transplantation of WT mesenchymal stem cells was demonstrated with western blotting and immunohistochemistry. After 4 days, the green fluoresces were noted on the wounds of mice injected with mesenchymal stem cells of fluorescent mice.

CONCLUSIONS

Mesenchymal stem cells can migrate to wound sites, and osteopontin plays a regulatory role in mesenchymal stem cells promoting the healing of diabetic skin wounds.

Potential of human fetal chorionic stem cells for the treatment of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a genetic bone pathology with prenatal onset, characterized by brittle bones in response to abnormal collagen composition. There is presently no cure for OI. We previously showed that human first trimester fetal blood mesenchymal stem cells (MSCs) transplanted into a murine OI model (oim mice) improved the phenotype. However, the clinical use of fetal MSC is constrained by their limited number and low availability. In contrast, human fetal early chorionic stem cells (e-CSC) can be used without ethical restrictions and isolated in high numbers from the placenta during ongoing pregnancy. Here, we show that intraperitoneal injection of e-CSC in oim neonates reduced fractures, increased bone ductility and bone volume (BV), increased the numbers of hypertrophic chondrocytes, and upregulated endogenous genes involved in endochondral and intramembranous ossification. Exogenous cells preferentially homed to long bone epiphyses, expressed osteoblast genes, and produced collagen COL1A2. Together, our data suggest that exogenous cells decrease bone brittleness and BV by directly differentiating to osteoblasts and indirectly stimulating host chondrogenesis and osteogenesis. In conclusion, the placenta is a practical source of stem cells for the treatment of OI.

[The comparative pathomorphological evaluation of the mice-recipient's brain cell-tissue reactions by the intracerebral imlantation of syngeneic and allogeneic neural cells]

The aim of the study was to compare the mice-recipient's brain tissue cell-structural reactions in response to intracerebral implantation of syngeneic and allogeneic cell suspensions of neural progenitor cells (NPC) (E13-15). The NPC suspensions from mice-donors of C57BL/6 and CBA containing 72.7 +/- 9.9% Vimentin+ and 81, 812, 5% GFAP+ cells were inoculated by standard procedure in right temporal segment of cerebral hemisphere of mice-recipients C57BL/6 (1 x 10(6) cells per animal). The certain part of mice-recipients of allogeneic NPC were immunosupressed by Sandimmune (100 mkg per animal) on day 0, 3, 6 after neurotransplantation. The standard histological preparations of mice brains were performed after 24 hours, 6, 12, 18 and 37 days after NPC neurotransplantation, which were investigated by cytoanalyzer "IBAS" (Germany). After intracerebral inoculation of allogeneic foetal NPC the signs of the pericellular edema and lymphocyte infiltration were detected in adjacent brain sections on day 12-18 and decreased on day 37. Allogeneic foetal NPC were reserved till day 18 and revealed the signs of primary differentiation. After immunosupression by "Sandimmune" the foetal NPC underwent the phoenotypic differentiation and infiltration in related brain sections. On the day 37 the implanted NPC were not detected. Focal reaction of the brain glial component to implanted NPC declined faster after syngeneic NPC neuroimplantation (up to day 18) than after allogeneic NPC neuroimplantation (up to day 37). After the syngeneic NPC inoculation on the 37th day at the site of implantation the formation of a small fragment of immature bone was fixed, which may indicate the possibility of NPC transdifferentiation in other cell types.

Safe genetic modification of cardiac stem cells using a site-specific integration technique

BACKGROUND

Human cardiac progenitor cells (hCPCs) are a promising cell source for regenerative repair after myocardial infarction. Exploitation of their full therapeutic potential may require stable genetic modification of the cells ex vivo. Safe genetic engineering of stem cells, using facile methods for site-specific integration of transgenes into known genomic contexts, would significantly enhance the overall safety and efficacy of cellular therapy in a variety of clinical contexts.

METHODS AND RESULTS

We used the phiC31 site-specific recombinase to achieve targeted integration of a triple fusion reporter gene into a known chromosomal context in hCPCs and human endothelial cells. Stable expression of the reporter gene from its unique chromosomal integration site resulted in no discernible genomic instability or adverse changes in cell phenotype. Namely, phiC31-modified hCPCs were unchanged in their differentiation propensity, cellular proliferative rate, and global gene expression profile when compared with unaltered control hCPCs. Expression of the triple fusion reporter gene enabled multimodal assessment of cell fate in vitro and in vivo using fluorescence microscopy, bioluminescence imaging, and positron emission tomography. Intramyocardial transplantation of genetically modified hCPCs resulted in significant improvement in myocardial function 2 weeks after cell delivery, as assessed by echocardiography (P=0.002) and MRI (P=0.001). We also demonstrated the feasibility and therapeutic efficacy of genetically modifying differentiated human endothelial cells, which enhanced hind limb perfusion (P<0.05 at day 7 and 14 after transplantation) on laser Doppler imaging.

CONCLUSIONS

The phiC31 integrase genomic modification system is a safe, efficient tool to enable site-specific integration of reporter transgenes in progenitor and differentiated cell types.

Ontological differences in first compared to third trimester human fetal placental chorionic stem cells

Human mesenchymal stromal/stem cells (MSC) isolated from fetal tissues hold promise for use in tissue engineering applications and cell-based therapies, but their collection is restricted ethically and technically. In contrast, the placenta is a potential source of readily-obtainable stem cells throughout pregnancy. In fetal tissues, early gestational stem cells are known to have advantageous characteristics over neonatal and adult stem cells. Accordingly, we investigated whether early fetal placental chorionic stem cells (e-CSC) were physiologically superior to their late gestation fetal chorionic counterparts (l-CSC). We showed that e-CSC shared a common phenotype with l-CSC, differentiating down the osteogenic, adipogenic and neurogenic pathways, and containing a subset of cells endogenously expressing NANOG, SOX2, c-MYC, and KLF4, as well as an array of genes expressed in pluripotent stem cells and primordial germ cells, including CD24, NANOG, SSEA4, SSEA3, TRA-1-60, TRA-1-81, STELLA, FRAGILIS, NANOS3, DAZL and SSEA1. However, we showed that e-CSC have characteristics of an earlier state of stemness compared to l-CSC, such as smaller size, faster kinetics, uniquely expressing OCT4A variant 1 and showing higher levels of expression of NANOG, SOX2, c-MYC and KLF4 than l-CSC. Furthermore e-CSC, but not l-CSC, formed embryoid bodies containing cells from the three germ layer lineages. Finally, we showed that e-CSC demonstrate higher tissue repair in vivo; when transplanted in the osteogenesis imperfecta mice, e-CSC, but not l-CSC increased bone quality and plasticity; and when applied to a skin wound, e-CSC, but not l-CSC, accelerated healing compared to controls. Our results provide insight into the ontogeny of the stemness phenotype during fetal development and suggest that the more primitive characteristics of early compared to late gestation fetal chorionic stem cells may be translationally advantageous.

[Dynamics of ultrastructural changes in the capillary endotheliocytes of the ischemic extremity in rats after transplantation of hematopoietic stem cells from the human fetal liver]

Experimental investigation was performed on the rats, in which the extremity ischemia was simulated to assess the application efficacy of hemopoietic stem cells, obtained from the human fetus liver, with the objective of angiogenesis activation. The perspective of the method application with the objective to stimulate the angiogenesis processes de novo in ischemia of the extremity, was studied, using the electron microscopy methods.

[Anti-aging effect of transplantation of mouse fetus-derived mesenchymal stem cells]

To determine the role of allogeneil graft of mesenchymal stem cells in mammalian longevity, mesenchymal stem cells were isolated from BALB/c mouse uterine-incision delivery fetus by two successive density gradient centrifugations, and then were purified and amplified by adherent culture. Identified P1 mesenchymal stem cells were injected (i.v.) through vena caudalis into the 15-month-old female BALB/c mice three times. The mice were evaluated with ultrasoundcardiogram, autopsy, score of cardiac, skin, lung, kidney, colon histopathology and serum total superoxide dismutase activity, maleic dialdehyde content, glutathione peroxidase activity. The results showed that after transplantation, the long-term surviving stem cells were found to be located in many organ tissues with in situ Y chromosomal hybridization dyeing. Median life span was increased in these animals after transplantation. Skin, cardiac, lung, kidney and colon pathology development were delayed. The retrogradation of heart function was attenuated, the increase of heart mass index (the mass of heart/the mass of the body), and serum maleic dialdehyde content, the decrease of spleen mass index (the mass of spleen/the mass of the body), serum total superoxide dismutase activity and glutathione peroxidase activity were reduced three months after transplantation (all P<0.05). These results support the idea that longevity can be enhanced by transplantation of mesenchymal stem cells and reinforce the hypothesis of mesenchymal stem cell as antiager.

Clinical study of transplantation of neural stem cells in therapy of inherited cerebellar atrophy

OBJECTIVE

To study the clinical effect of neural stem cell transplantation in the treatment of inherited cerebellar atrophy (CA).

METHODS

The cells from human fetal cerebellum (8-10 weeks of gestation) were grown and expanded in vitro. The cultured neurospheres were then planted into the dentate nuclei of patients by stereo tactic operation. Totally, 12 patients (7 males and 5 females with age ranging 22-62 years, mean 43 years) were treated by this operation from August 2006 to August 2008.

RESULTS

The cells of fetal cerebellum were expanded by 10(7) folds in undifferentiated state in the culture. After the operation, no rejection was detected. Follow up, the effective rates were 58.3% after 3 months, 75.0% after 6 months, and 66.7% for 12-24 months (mean 18 months).

CONCLUSION

The transplantation of in vitro cultured neural stem cell is a feasible and effective treatment for inherited CA, but the long term effectiveness need to be taken in consideration.

Single Neural Progenitor Cells Derived from EGFP Expressing Mice is Useful After Spinal Cord Injury in Mice

Neural stem cells (NSCs) were widely used for studying the cell's replacement after transplantation in nervous system because of its specific characteristics. However, Stracing the cells after transplantation was still a problem. In the present study, we isolated and cultured the neural stem cells from the C57BL/6J EGFP transgenic mouse (EGFP mice), and identified the capacity for self-renewal and differentiation into the three CNS lineages (neurons, astrocytes, and oligodendrocytes). Then we transplanted the single neural stem cell into the lesion spinal cord. Expression of GFP and differentiation was evaluated at two weeks post-transplantation. The data showed that these neural stem cells derived from the EGFP mice could maintain transgene expression and could differentiate into the MAP2 positive cells after transplantation into the injured spinal cord. The results suggested that NSC expressing EGFP was a useful marker for tracing the cells after transplantation in vivo and functional in the treatment to spinal cord injury.

Human CD133+ progenitor cells promote the healing of diabetic ischemic ulcers by paracrine stimulation of angiogenesis and activation of Wnt signaling

We evaluated the healing potential of human fetal aorta-derived CD133(+) progenitor cells and their conditioned medium (CD133(+) CCM) in a new model of ischemic diabetic ulcer. Streptozotocin-induced diabetic mice underwent bilateral limb ischemia and wounding. One wound was covered with collagen containing 2x10(4) CD133(+) or CD133(-) cells or vehicle. The contralateral wound, covered with only collagen, served as control. Fetal CD133(+) cells expressed high levels of wingless (Wnt) genes, which were downregulated following differentiation into CD133(-) cells along with upregulation of Wnt antagonists secreted frizzled-related protein (sFRP)-1, -3, and -4. CD133(+) cells accelerated wound closure as compared with CD133(-) or vehicle and promoted angiogenesis through stimulation of endothelial cell proliferation, migration, and survival by paracrine effects. CD133(+) cells secreted high levels of vascular endothelial growth factor (VEGF)-A and interleukin (IL)-8. Consistently, CD133(+) CCM accelerated wound closure and reparative angiogenesis, with this action abrogated by co-administering the Wnt antagonist sFRP-1 or neutralizing antibodies against VEGF-A or IL-8. In vitro, these effects were recapitulated following exposure of high-glucose-primed human umbilical vein endothelial cells to CD133(+) CCM, resulting in stimulation of migration, angiogenesis-like network formation and induction of Wnt expression. The promigratory and proangiogenic effect of CD133(+) CCM was blunted by sFRP-1, as well as antibodies against VEGF-A or IL-8. CD133(+) cells stimulate wound healing by paracrine mechanisms that activate Wnt signaling pathway in recipients. These preclinical findings open new perspectives for the cure of diabetic ulcers.

Graft outcomes influenced by co-expression of Pax7 in graft and host tissue

Cell replacement therapies offer promise in the treatment of neurotrauma and neurodegenerative disorders and have concentrated on the use of primary fetal brain tissue. However, there is a growing promise of using neural stem cells, in which case other factors may be important in their successful engraftment. We therefore investigated whether the co-expression of the major developmental transcription factor (Pax7 in this study) of donor tissue to graft site influences transplant survival and differentiation in the rat midbrain. Neural progenitor cells were prepared from either the Pax7-expressing dorsal (DM) or non-Pax7-expressing ventral mesencephalon (VM) of embryonic EGFP(+/+) rats. Cells were dissociated and grafted into the adult rat superior colliculus (SC) lesioned with quinolinic acid 3 days previously, a time shown to be associated with the up-regulation of Pax7. Grafts were then examined 4 weeks later. Our results suggest the origin of the graft tissue did not alter graft survival in the SC; however, dorsal grafts appear to have a higher incidence of neuronal survival, whereas ventral grafts have a higher incidence of astrocytic survivors.

Rescue of multi-lineage hematopoiesis during HIV-1 infection by human c-mpl gene transfer and reconstitution of CD34+ progenitor cells in vivo

Cytopenias arising from hematopoietic abnormalities are a severe common complication contributing to early mortality in HIV/AIDS patients. The proto-oncogene c-mpl, identified as the thrombopoietin receptor is involved in multilineage differentiation of CD34+ hematopoietic progenitor cells. We have introduced the c-mpl gene into CD34+ cells via transduction of the lentivirus p156RRLsinPPTmPGK-CMPL-PRE. The lentiviral construct expresses c-mpl on approximately 90% of purified CD34+ cells. These transduced cells have then been reconstituted into human fetal thymus/liver implants in severe combined immunodeficient mice (SCID-hu Thy/Liv). The c-mpl expression on transduced CD34+ cells is not susceptible to downregulation due to the effects of HIV-1 infection. Reconstituted CD34+ cells transduced with control lentivirus, p156RRLsinPPTmPGK-EGFP-PRE, express EGFP at > 90%. Reconstituted c-mpl expressing SCID-hu implants show almost maximum rescue (approximately 90%) of myelopoiesis, erythropoiesis and megakaryopoiesis, during HIV-1 infection in vivo, at 6 weeks post-infection. We also show that the differentiated multi-lineage progeny colonies and thymocytes in mice reconstituted with the c-mpl transduced CD34+ cells, carry the HLA Class I loci phenotypes of these donor cells, in the implants of the recipient SCID-hu animals. We propose a gene therapeutic strategy, with c-mpl as the major genetic component, to address the morbidity and mortality resulting from cytopenias in HIV infected patients.

[Migration and differentiation of transplanted fetal neurogenic cells in animals with brain ischemia]

The migration, integration and differentiation of fetal neural progenitor cells (NPCs) in the ischemic brain have been studied. In our study the ischemic insult in FVB line mice was produced by occlusion of both carotid arteries during 20 min. A day after occlusion NPCs from GFP-transgenic 12.5 dpc embryos were suboccipitally transplanted to the ischemic brain. The migration and differentiation of GFP-positive NPCs in the recipient tissue were observed in different time points after their transplantation by immunohistochemical approaches using confocal scanning microscopy. It has been shown that GFP-positive NPCs survived, migrated and differentiated to the mature neurons and glial cells in CA1 area of hippocampus of ischemic animals.

How work reconfigures an 'unwanted' pregnancy into 'the right tool for the job' in stem cell research

Tissue derived from the aborted fetus is considered 'the right tool for the job' in some stem cell laboratories. Relatively little is known of the arrangements in Britain for sourcing aborted fetuses for research purposes. This paper uses data from interviews with stem cell scientists, policy makers, tissue bankers, sponsors of stem cell research, clinicians and nurses, and 'pro-choice' and 'pro-life' activists to reconstruct the work involved in reconfiguring an 'unwanted' pregnancy into a source of fetal stem cells. A close scrutiny of the work allows the politics of collections to emerge. Aborted fetuses undergo a process of decorporealisation that enables scientists to claim them for their professional and economic advantage. The work, however, has consequences for women rhetorically through being reconfigured into a repository of usable fetal tissue, and, in some sites, materially, through alteration in method of abortion.

[Cell therapy for Parkinson's disease: III. Neonatal, fetal and embryonic stem cell-based applications]

Motor dysfunctions in Parkinson's disease are believed to be primarily due to the degeneration of dopaminergic neurons located in the substantia nigra pars compacta. Numerous cell replacement therapy approaches have been developed and tested, including these based on donor cell transplantation (embryonic and adult tissue-derived), adult mesenchymal stem cells (hMSCs)-, neural stem cells (hNSCs)- and finally human embryonic stem cells (hESCs)-based. Despite the progress achieved, numerous difficulties prevent wider practical application of stem cell-based therapy approaches for the treatment of Parkinson's disease. Among the latter, ethical, safety and technical issues stand out. Current series of reviews (Cell therapy for Parkinson's disease: I. Embryonic and adult donor tissue-based applications; II. Adult stem cell-based applications; III. Neonatal, fetal and embryonic stem cell-based applications; IV. Risks and future trends) aims providing a balanced and updated view on various issues associated with cell types (including stem cells) in regards to their potential in the treatment of Parkinson's disease. Essential features of the individual cell subtypes, principles of available cell handling protocols, transplantation, and safety issues are discussed extensively.

Expansion of Bcr-Abl-positive leukemic stem cells is dependent on Hedgehog pathway activation

Resistance of Bcr-Abl-positive leukemic stem cells (LSCs) to imatinib treatment in patients with chronic myeloid leukemia (CML) can cause relapse of disease and might be the origin for emerging drug-resistant clones. In this study, we identified Smo as a drug target in Bcr-Abl-positive LSCs. We show that Hedgehog signaling is activated in LSCs through upregulation of Smo. While Smo(-/-) does not impact long-term reconstitution of regular hematopoiesis, the development of retransplantable Bcr-Abl-positive leukemias was abolished in the absence of Smo expression. Pharmacological Smo inhibition reduced LSCs in vivo and enhanced time to relapse after end of treatment. Our results indicate that Smo inhibition might be an effective treatment strategy to reduce the LSC pool in CML.

How to improve the survival of the fetal ventral mesencephalic cell transplanted in Parkinson's disease?

It has been extensively confirmed that fetal ventral mesencephalic cell (VMC) transplantation can ameliorate the symptoms of Parkinson's disease (PD). But there are still several problems to be resolved before the extensive clinical application of this technology. The major limitations are the poor survival of grafted dopamine (DA) neurons and restricted dopaminergic reinnervation of host striatum. Some attempts have been made to solve these problems including use of some trophic factor and co-transplantation with neural/paraneural origins. The purpose of this review is to overview advances of the means improving the survival of grafts and their current limitations.

[Effect of fetal tissues on the processes of thymus involution in experiment]

The objective of the experiment was to investigate the effect of liver fetal tissue transplantation (LFTT) in adult rats on the morphofunctional state of thymus as the central organ of cell-mediated (cellular) immunity. A positive impact of LFTT on the indices of age-dependent thymus involution has been established. That revealed itself in the corresponding morphological transformations of the microenvironment of thymocytes, changes in their number and composition as well as in the subpopulation composition of lymphocytes of the peripheral blood. The studies undertaken testify to the great possibilities (potentialities) of further research into the application of fetal hemopoietic tissues aimed at correcting age-dependent disorders of the cellular immunity link.

Expression of SDF-1-CXCR4 axis and an anti-remodelling effectiveness of foetal-liver stem cell transplantation in the infarcted rat heart

SDF-1, a chemokine secreted by injured tissues, may be instrumental in chemoattracting CXCR4(+) stem cells (SCs) for repair of infarcted myocardium. We hypothesize that the myocardial SDF-1 expression determines also the engraftment and beneficial effects of SCs transplanted into the infarcted heart. Myocardial infarction (MI) was induced in rats by coronary artery ligation. The animals were either sacrificed at 2, 7, 16, 21 or 28 days after MI or were re-operated at 2, 7 or 14 days after MI to receive SCs transplantation, and were sacrificed 14 days later. SCs transplantation consisted of 3 x 15 microl injections of SCs isolated from foetal rat liver (FLSCs) into the myocardium bordering the infarction zone (5 x 10(6) cells/heart, labelled with PKH2 Green Fluorescent Cell Linker, approximately 20% CXCR4(+)). In the MI border zone, SDF-1 and CXCR4 immunostaining was transiently increased after MI, picking at 2 days and down regulating to the sham level by 21 days after MI. Simultaneously, an increased incorporation of CXCR4(+) and CD133(+) cells into capillaries was evident. AMD1300, a blocker of CXCR4, prevented the post-MI expression of CXCR4. In the MI border zone, the cardiomyocyte cross-sectional diameter increased and capillary/cardiomyocyte ratio decreased systematically during the 28 post-MI days, while an interstitial collagen accumulation demonstrated transient increase. FLSCs did not survive in the non-infarcted hearts. In infarcted hearts, FLSCs survived best when they were injected at 2 days after MI. The survival was negligible again when the injection was performed at 14 days after MI. FLSCs transplanted at 2 days after MI caused a further rise in SDF-1, CXCR4, and CD133 expression, compared with the untreated infarcted hearts. Only FLSCs transplanted at 2 days, but not later, attenuated cardiomyocyte hypertrophy and increased capillary/cardiomyocyte ratio in the MI border zone. These results suggest that myocardial signalling for homing of the endogenous and the exogenous SCs is transiently activated early after MI, that SDF-1 is instrumental in this process, and that there is only a narrow time-window after MI when SCs transplantation results in their efficient myocardial engraftment and beneficial anti-remodelling effect.

Stem cell therapies for perinatal brain injuries

This chapter reviews four groups of paediatric brain injury. The pathophysiology of these injuries is discussed to establish which cells are damaged and therefore which cells represent targets for cell replacement. Next, we review potential sources of cellular replacements, including embryonic stem cells, fetal and neonatal neural stem cells and a variety of mesenchymal stem cells. The advantages and disadvantages of each source are discussed. We review published studies to illustrate where stem cell therapies have been evaluated for therapeutic gain and discuss the hurdles that will need to be overcome to achieve therapeutic benefit. Overall, we conclude that children with paediatric brain injuries or inherited genetic disorders that affect the brain are worthy candidates for stem cell therapeutics.

Bone healing and migration of cord blood-derived stem cells into a critical size femoral defect after xenotransplantation

Stem cell and tissue engineering-based therapies have become a promising option to heal bony defects in the future. Human cord blood-derived mesenchymal stem cells were seeded onto a collagen/tricalcium phosphate scaffold and xenotransplanted into critical size femoral defects of 46 nude rats. We found a survival of human cells within the scaffold and surrounding bone/bone marrow up to 4 wk after transplantation and an increased bone healing rate compared with controls without stem cells. This study supports the application of cord blood stem cells for bone regeneration.

INTRODUCTION

The treatment of critical size bone defects is still a challenging problem in orthopedics. In this study, the survival, migration, and bone healing promoting potency of cord blood-derived stem cells were elucidated after xenotransplantation into a critical size femoral defect in athymic nude rats.

MATERIALS AND METHODS

Unrestricted somatic stem cells (USSCs) isolated from human cord blood were tested toward their mesenchymal in vitro potency and cultivated onto a collagen I/III and beta-tricalcium phosphate (beta-TCP) scaffold. The biomaterial-USSC composite was transplanted into a 4-mm femoral defect of 40 nude rats and stabilized by an external fixator. Twelve animals without USSCs served as controls. Cell survival, migration, and bone formation were evaluated by blood samples, X-rays, and histological and immunocytochemical analysis of different organs within a maximal postoperative follow-up of 10 wk.

RESULTS

Of the 52 nude rats, 46 animals were evaluated (drop-out rate: 11.5%). Human-derived stem cells showed an engraftment within the scaffold and adjacent femur up to 4 wk after xenotransplantation. With further time, the human cells were destroyed by the host organism. We found a significant increase in bone formation in the study group compared with controls. USSC transplantation did not significantly influence blood count or body weight in athymic nude rats. Whereas the collagen I/III scaffold was almost resorbed 10 wk after transplantation, there were still significant amounts of TCP present in transplantation sites at this time.

CONCLUSIONS

Human cord blood-derived stem cells showed significant engraftment in bone marrow, survived within a collagen-TCP scaffold up to 4 wk, and increased local bone formation in a nude rat's femoral defect.

[D2 receptor expression on immortalized human neural progenitor cell line hNPC-TERT in vitro and in vivo]

OBJECTIVE

To observe D(2) receptor expression on human neural progenitor cell line hNPC-TERT before and after transplantation into rabbit central nervous system.

METHODS

D(2) receptor expression on cultured hNPC-TERT cells was verified and quantitatively analyzed with immunofluorescence assay and receptor radio ligand binding assay, respectively. 3 x 10(6) hNPC-TERT cells were implanted in the spinal cord of New Zealand rabbit with HeLa cells as the control. Two days after implantation, positron-emission tomography (PET) scan with (11)C-raclopride as the radiotracer was performed in the living animals or for the isolated spinal cords, and cryosections of the spinal cord containing the implanted cells were prepared for immunofluorescence assay.

RESULTS

Cultured hNPC-TERT cells showed high expression of D(2) receptor (Bmax=8 x 10(4)). PET scans of the rabbits identified visible radioactive accumulations at the site where hNPC-TERT cells were implanted but not at the site of HeLa cell implantation. Region of interest analysis showed a significant difference between the two cells in the maximal standard uptake value at the cell implantation sites. The results were further confirmed with ex vivo PET imaging of the spinal cord and tissue immunofluorescence assay.

CONCLUSION

Human neural progenitor cells hNPC-TERT highly express dopamine D(2) receptors and retain this capacity after implantation into the spinal cord, suggesting their potential for treatment of such nerve system disease as Parkinson syndrome.

[Intrasplenic heterotransplantation of in vitro cultured human fetal hepatic stem cells for treatment of acute liver injury in mice with severe combined immunodeficiency]

OBJECTIVE

To observe the in vivo colonization, migration, and differentiation of in vitro cultured human fetal hepatic stem cells (HSCs) following intrasplenic transplantation for treatment of acute liver injury in mice with severe combined immunodeficiency (SCID).

METHODS

Human fetal HSCs were isolated from the normal fetal liver (16-24 weeks) and purified, and the morphology of HSCs was observed under optical and transmission electron microscopes. The expressions of stem cell markers were examined in these HSCs by means of immunocytochemistry and flow cytometry. The passaged human fetal HSC suspension (0.2 ml) were injected into the spleen of SCID mice with acute liver injury induced by two-third partial hepatectomy, and 15, 30, 60, and 90 days after cell transplantation, immunohistochemistry was performed to examine the location and expressions of human hepatocytes, alpha1-AT and AFP antigen in the spleen and liver of the recipient SCID mice. PAS staining was used to examine the expression of glycogen and RT-PCR employed for detection of the expressions of AFP and albumin mRNA in the spleen of the mice on the scheduled time points.

RESULTS

Under optical microscope and transmission electron microscope, most of the HSCs were small, about 1/6 to 1/3 of the size of the hepatocyte, with relatively large nucleus-cytoplasm ratio and only small quantities of endocytoplasmic reticulum, chondriosome, and ribosome. Immunohistochemistry and flow cytometry identified positive expressions of AFP, Thy-1, C-kit, CD34 and CK19 in the HSCs, and after cell transplantation, positive expressions of human hepatocyte, alpha1-AT, and AFP antigen occurred in the liver and spleen of the recipient SCID mice. PAS staining confirmed the presence of glycogenosome in the spleen of the mice following cell transplantation. RT-PCR on days 30, 60, and 90 showed positive expressions of human AFP and albumin mRNA in the spleen of the mice.

CONCLUSION

Human fetal HSCs can survive and settle in the spleen and liver, and migrate to the damaged liver of the recipient mice after intrasplenic transplantation, with the capacity of proliferation and differentiation into hepatocytes in the recipient target organs.

Long-term culture and neuronal survival after intraspinal transplantation of human spinal cord-derived neurospheres

There is heterogeneity in neural stem and progenitor cell characteristics depending on their species and regional origin. In search for potent in vitro-expanded human neural precursor cells and cell therapy methods to repair the injured human spinal cord, the possible influence exerted by intrinsic cellular heterogeneity has to be considered. Data available on in vitro-expanded human spinal cord-derived cells are sparse and it has previously been difficult to establish long-term neurosphere cultures showing multipotentiality. In the present paper, human spinal cord-derived neurospheres were cultured in the presence of EGF, bFGF and CNTF for up to 25 passages (>350 days) in vitro. In contrast to the human first trimester subcortical forebrain, spinal cord tissue>9.5 weeks of gestation could not serve as a source for long-term neurosphere cultures under the present conditions. After withdrawal of mitogens, cultured neurospheres (at 18 passages) gave rise to cells with neuronal, astrocytic and oligodendrocytic phenotypes in vitro. After transplantation of human spinal cord-derived neurospheres to the lesioned spinal cord of immuno-deficient adult rats, large numbers of cells survived at least up to 6 weeks, expressing neuronal and astrocytic phenotypes. These results demonstrate that it is possible to expand and maintain multipotent human spinal cord-derived neurospheres in vitro for extended time-periods and that they have promising in vivo potential after engraftment to the injured spinal cord.

[Application of cell technologies for therapy of chronic renal insufficiency (experimental study)]

The experiments on 29 white non-inbred rats with chronic renal failure (CRF) induced by right-side nephrectomy and coagulation of 1/2-2/3 of parenchyma of the left kidney were made to study the trend in renal function after injection (into renal cortex or intravenously) of cultured stem or progenitor cells from human fetuses (total culture of fetal kidney or mesenchymal stem cells of the bone marrow). In control tests with salt solution functional indices reflected persistence of CRF. On day 4 after introduction of the fetal cells into renal parenchyma renal function improved and normalized in 2 weeks. After intravenous injection of fetal cells CRF reduced slowly, especially after injection of medullary mesenchymal cells with normalization in 1 month. 2.5-3.5 months after the injection test parameters in some rats deteriorated but remained close to normal values. Glomerular filtration after injection of stem and progenitor cells recovered better while canalicular sodium reabsorption underwent normalization but was followed by deterioration.

Brain stem cells adopt a pituitary fate after implantation into the adult rodent pituitary gland

Fetal brain stem cells (RSCs) have been induced to express pituitary phenotypes in vitro in co-cultures with GH(3) cells and by exposure to GH(3)-conditioned media. In the current studies, we graft RSCs into the pituitary glands of adult rat to investigate whether grafted RSCs can be induced by the native gland to acquire pituitary properties. Grafted cells survive for 4 weeks and express Pit-1, GH, FSH, LH, ACTH, TSH and to a lesser extent PRL indicating that inductive influences are operative in vivo as well. This demonstrates that pluripotential cells can be induced to acquire properties of tissues different from their organ of origin likely through the action of cell-cell contact and local tissue factors.

Hepatocyte transplantation: studies in preclinical models

Transplantation of allogeneic or genetically modified autologous hepatocytes may be an alternative to whole-liver transplantation for the treatment of hereditary metabolic liver diseases. Human hepatocytes have already been transplanted in patients, demonstrating the safety and feasibility of both approaches. Although a few cases of allogeneic transplantation have resulted in long-term engraftment and function, only a partial and transient correction of the disease was achieved. This may partly result from a lack of proliferation of transplanted cells. In rodents, transplanted hepatocytes do not proliferate in adult quiescent livers and repopulate recipient livers only when they display a proliferative advantage over resident hepatocytes. Most of these models are not transposable to humans, however. Our aim is to develop preclinical approaches to hepatocyte transplantation in nonhuman primates. We have defined a strategy that increases the engraftment efficiency of transplanted hepatocytes by inducing their proliferation together with that of resident hepatocytes. We have also immortalized simian fetal hepatic progenitor cells and shown that these cells do not proliferate in situ after transplantation into the livers of immunodeficient mice. By contrast early human hepatoblasts repopulate mouse livers more efficiently. However, if we consider the number of cells to be transplanted (one to several billion), the means of expanding and differentiating stem or progenitor cells other than hepatocytes will have to be determined prior to envisaging treating patients.

[Transplantation of human fetal neural stem cells into cerebral ventricle of the neonatal rat following hypoxic-ischemic injury: survival, migration and differentiation]

OBJECTIVE

Neonatal hypoxic-ischemic encephalopathy (HIE) harms the lives and health of newborn infants and children severely. Given the absence of effective therapies for HIE, it is important to derive new strategies. Neural stem cells (NSCs) have great potential as a therapeutic tool for the repair of a number of central nervous system disorders that involve cell loss. This study was designed to transplant the neural stem cells derived from human fetal brain (hNSCs) into cerebral ventricle of neonatal rat following hypoxic-ischemic injury and to investigate their survival, migration and differentiation in rat brain.

METHODS

Cells obtained from the forebrain of a 12-week old fetus were cultured in the presence of epidermal growth factor, basic fibroblast growth factor and leukemia inhibitory factor for 11 days. Animal models were built in 7-day-postnatal Wistar rats, 3-days after hypoxia-ischemia (HI), 5 microl suspension containing 5.0 x 10(5) hNSCs was injected into the left cerebral ventricle of each HIE rat by using stereotactic instrument. No immunosuppression therapy was given to the animals. At 1, 2, 4 weeks and 3 months after transplantation, the rats were sacrificed and brain tissues were harvested and were then examined by H-E staining and immunohistochemical analysis.

RESULTS

Implanted cells expressing human nuclear protein (hNP) migrated form the subventricular zone (SVZ) along corpus callosum to the damaged areas, especially to the injured side of cortex and hippocampus. In different areas, the implanted hNSCs differentiated into different cell types which were similar to the host cells. The 85% implanted cells in cortex consisted of hNuc-NF or hNuc-Tublin double positive cells, while in the migratory way, 60% implanted cells differentiated into hNuc-GFAP double positive cells. Compared with the 1-week time point, an increased number of hNP-positive cells were observed at 2-weeks, but the number of these cells greatly decreased at 4-weeks and 3 months.

CONCLUSION

The implanted hNSCs could extensively survive, migrate in the brain of neonatal rat with HIE and could differentiate into neurons and astrocytes in a regionally specific manner.