Fetal Striatal Transplantation Research Articles

Survival of iPSC-derived grafts within the striatum of immunodeficient mice: Importance of developmental stage of both transplant and host recipient

Degeneration of the striatum can occur in multiple disorders with devastating consequences for the patients. Infantile infections with streptococcus, measles, or herpes can cause striatal necrosis associated with dystonia or dyskinesia; and in patients with Huntington's disease the striatum undergoes massive degeneration, leading to behavioral, psychological and movement issues, ultimately resulting in death. Currently, only supportive therapies are available for striatal degeneration. Clinical trials have shown some efficacy using transplantation of fetal-derived primary striatal progenitors. Large banks of fetal progenitors that give rise to medium spiny neurons (MSNs), the primary neuron of the striatum, are needed to make transplantation therapy a reality. However, fetal tissue is of limited supply, has ethical concerns, and is at risk of graft immunorejection. An alternative potential source of MSNs is induced pluripotent stem cells (iPSCs), adult somatic tissues reprogrammed back to a stem cell fate. Multiple publications have demonstrated the ability to differentiate striatal MSNs from iPSCs.Previous publications have demonstrated that the efficacy of fetal progenitor transplants is critically dependent upon the age of the donor embryo/fetus as well as the age of the transplant recipient. With the advent of iPSC technology, a question that remains unanswered concerns the graft's “age,” which is crucial since transplanting pluripotent cells has an inherent risk of over proliferation and teratoma formation. Therefore, in order to also determine the effect of transplant recipient age on the graft, iPSCs were differentiated to three stages along a striatal differentiation paradigm and transplanted into the striatum of both neonatal and adult immunodeficient mice. This study demonstrated that increased murine transplant-recipient age (adult vs neonate) resulted in decreased graft survival and volume/rostro-caudal spread after six weeks in vivo, regardless of “age” of the cells transplanted. Importantly, this study implicates that the in vivo setting may provide a better neurogenic niche for iPSC-based modeling as compared to the in vitro setting. Together, these results recapitulate findings from fetal striatal progenitor transplantation studies and further demonstrate the influence of the host environment on cellular survival and maturation.

Donor-Specific Anti-HLA Antibodies in Huntington's Disease Recipients of Human Fetal Striatal Grafts

Fetal grafting in a human diseased brain was thought to be less immunogenic than other solid organ transplants, hence the minor impact on the efficacy of the transplant. How much prophylactic immune protection is required for neural allotransplantation is also debated. High-sensitive anti-HLA antibody screening in this field has never been reported. Sixteen patients with Huntington's disease underwent human fetal striatal transplantation in the frame of an open-label observational trial, which is being carried out at Florence University. All patients had both brain hemispheres grafted in two separate robotic-stereotactic procedures. The trial started in February 2006 with the first graft to the first patient (R1). R16 was given his second graft on March 2011. All patients received triple immunosuppressive treatment. Pre- and posttransplant sera were analyzed for the presence of anti-HLA antibodies using the multiplexed microsphere-based suspension array Luminex xMAP technology. Median follow-up was 38.5 months (range 13-85). Six patients developed anti-HLA antibodies, which turned out to be donor specific. Alloimmunization occurred in a time window of 0-49 months after the first neurosurgical procedure. The immunogenic determinants were non-self-epitopes from mismatched HLA antigens. These determinants were both public epitopes shared by two or more HLA molecules and private epitopes unique to individual HLA molecules. One patient had non-donor-specific anti-HLA antibodies in her pretransplant serum sample, possibly due to previous sensitization events. Although the clinical significance of donor-specific antibodies is far from being established, particularly in the setting of neuronal transplantation, these findings underline the need of careful pre- and posttransplant immunogenetic evaluation of patients with intracerebral grafts.

Fibroblast growth factor and endothelin-1 receptors mediate the response of human striatal precursor cells to hypoxia

Fetal striatal transplantation has emerged as a new therapeutic strategy in Huntington’s disease (HD). Hypoxia is one of the microenvironmental stress conditions to which fetal tissue is exposed as soon as it is isolated and transplanted into the diseased host brain. Mechanisms that support neuroblast survival and replenishment of damaged cells within the HD brain in the hypoxic condition have yet to be fully elucidated. This study is aimed at investigating the molecular pathways associated with the hypoxic condition in human fetal striatal neuroblasts (human striatal precursor (HSP) cells), using the hypoxia-mimetic agent cobalt chloride (CoCl2). We analyzed the effect of CoCl2 on HSP cell proliferation and on the expression of hypoxia-related proteins, such as hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF). Moreover, we evaluated fibroblast growth factor 2 (FGF2; 50ng/ml) and endothelin-1 (ET-1; 100nM) proliferative/survival effects in HSP cells in normoxic and hypoxic conditions. Dose–response experiments using increasing concentrations of CoCl2 (50–750μM) showed that the HSP cell growth was unaffected after 24h, while it increased at 48h, with the maximal effect observed at 400μM. In contrast, cell survival was impaired at 72h. Hypoxic conditions determined HIF-1α protein accumulation and increased gene and protein expression of VEGF, while FGF2 and ET-1 significantly stimulated HSP cell proliferation both in normoxic and hypoxic conditions, thus counteracting the apoptotic CoCl2 effect at 72h. The incubation with selective receptor (FGFR1, endothelin receptor A (ETA) and endothelin receptor B (ETB)) inhibitors abolished the FGF2 and ET-1 neuroprotective effect. In particular, ET-1 stimulated HSP cell survival through ETA in normoxic conditions and through ETB during hypoxia. Accordingly, ETA expression was down-regulated, while ETB expression was up-regulated by CoCl2 treatment. Overall, our results support the idea that HSP cells possess the machinery for their adaptation to hypoxic conditions and that neurotrophic factors, such as FGF2 and ET-1, may sustain neurogenesis and long-term survival through complex receptor-mediated mechanisms.

Large-sized Fetal Striatal Grafts in Huntington's Disease Do Stop Growing: Long-term Monitoring in the Florence Experience.

Development of six large nodules of solid tissue after bilateral human fetal striatal transplantation in four Huntington’s disease patients has raised concern about the safety of this experimental therapy in our setting. We investigated by serial MRI-based volumetric analysis the growth behaviour of such grafts. After 33-73 months from transplantation the size of five grafts was stable and one graft showed a mild decrease in size. Signs neither of intracranial hypertension nor of adjuctive focal neurological deficit have ever been observed. This supports long-term safety of the grafting procedure at our Institution.

The long-term safety and efficacy of bilateral transplantation of human fetal striatal tissue in patients with mild to moderate Huntington's disease

Huntington's disease (HD) is a fatal autosomal dominant neurodegenerative disease involving progressive motor, cognitive and behavioural decline, leading to death approximately 20 years after motor onset. The disease is characterised...

FGF2 and ET1 promote human fetal striatal neuroblasts survival in hypoxic conditions

Fetal striatal transplantation emerged as a new strategy to promote reparative responses in Huntington’s disease (HD) patients1. Mechanisms that support neuroblasts survival and replenishment of damaged cells within the HD brain in hypoxia remain to be elucidated. This study investigated how human fetal striatal neuroblasts (HSP cells) respond to hypoxia, using the hypoxia-mimetic agent cobalt chloride (CoCl2)2. We analyzed CoCl2 effect on hypoxia-related proteins, such as HIF-1α and VEGF, and on a neuroprotective factor, such as Seladin-1. Moreover, we evaluated FGF2 (50 ng/ml) and ET1 (100 nM) proliferative/survival effects in HSP cells in normoxic and hypoxic conditions. These growth factors could be important mediators under pathological conditions for striatal neuroblasts function and response to hypoxia. Dose-response experiments with increasing concentration of CoCl2 (50-750 um) showed an increase of HSP cell proliferation at 24-48h, with maximal effects observed at 400 um, while cell survival was impaired at 72h. Hypoxia increased protein expressions of HIF-1α and VEGF, whereas decreased Seladin-1 levels. FGF2 and ET1 significantly stimulated HSP cells proliferation both in normoxic and hypoxic condition, counteracting the apoptotic CoCl2 effect at 72h. FGF2 and ET1 neuroprotective effect was abolished by the selective inhibition of their receptors (FGFR1, ETA and ETB). In particular, ET1 stimulated HSP cells survival through ETA receptor in normoxic condition and through ETB receptor during hypoxia. Our results support the idea that FGF2 and ET1 promote neurogenesis and survival of HSP cells, through receptor-mediated mechanisms, when grafted into the hypoxic HD brain.

Q11 Huntington's disease Italian trial in neuro-transplantation: update on 17 patients group

IntroductionEmbryonic striatal cells grafts transplanted into rat striatum have been shown to be effective in reversing behavioural deficits, including motor and cognitive impairments in Huntington's disease (HD) rat models. For...

Plasticity and therapeutic potential of human fetal tissue

Rebuilding of brain structures and nervous circuitries with grafting of fetal tissue is currently being explored as a strategy to repair the damaged nervous system (Handb Clin Neurol 2009). Experimental studies demonstrated that transplanted neuroblasts can survive and proliferate in the host. Migration of primary or expanded neural precursors following transplantation has also been well documented. Cell migration plays a pivotal role in the organogenesis and contributes to multiple processes in adulthood, such as tissue repair and immune response. Migrating neuroblasts are capable of anatomically re-establishing damaged neural circuitries in the adult animal brain. These results suggest that there might also be a real potential for neurotransplantation in humans in order to promote reconstruction after brain injury. The challenge of such an approach is that the primordium recapitulates its ontogenesis in the host, being deprived of the fetal brain environmental cues, while it is subject to extrinsic cues coming from the diseased adult brain. In animals, recapitulation of normal development was achieved “simply“ by implanting fetal neurons. Striatal fetal grafting as a strategy of cell replacement has been extensively investigated in Huntington’s disease (HD) animal models. There is evidence that primary grafts of human fetal striatal tissue contain proliferative cells capable of migrating, differentiating and establishing robust graft-host interconnectivity, significantly recovering lesion-induced damage, without graft overgrowth or neoplastic proliferation (Lancet Neurol 2006). Based on these studies and the fact that current therapies do not prevent the unrelenting clinical course of HD, a clinical trial of human fetal striatal tissue transplantation for the treatment of HD has been initiated at the University of Florence. Fifteen HD patients underwent bilateral transplantation. The current report provides the first “in vivo“ evidence that unmanipulated grafted neural precursors from human striatal anlagen developed within the diseased striatum of HD patients and moved into the adult brain, reaching shortand long-distance appropriate anatomical targets. The anlagen development resulted in the building of metabolically active new nervous structures displaying striatal-like imaging features (Exp Neurol 2008, 2010). These events were accompanied by beneficial effects on the disease clinical course without negative outcomes, such as grafted tissue overgrowth or cyst formation.

Human striatal neuroblasts develop and build a striatal-like structure into the brain of Huntington's disease patients after transplantation

Rebuilding brain structure and neural circuitries by transplantation of fetal tissue is a strategy to repair the damaged nervous system and is currently being investigated using striatal primordium in Huntington's disease (HD) patients. Four HD patients underwent bilateral transplantation with human fetal striatal tissues (9-12 week gestation). Small blocks of whole ganglionic eminencies were processed to obtain cell suspension and then stereotactically grafted in the caudate head and in the putamen. Follow-up period ranged between 18 and 34 months (mean, 24.7 months). Surgery was uneventful. Starting from the fourth month after grafting, neo-generation of metabolically active tissue with striatal-like MRI features was observed in 6 out of 8 grafts. The increase in D2 receptor binding suggested striatal differentiation of the neo-generated tissue in 3 patients. New tissue, connecting the developing grafts with the frontal cortex and, in one case, with the ventral striatum, was also observed. The new tissue growth halted after the ninth month post transplantation. All patients showed stabilization or improvement in some neurological indices. No clinical and imaging signs, suggestive of graft uncontrolled growth, were seen. This study provides the first evidence in humans that neuroblasts of a striatal primordium can develop and move into the brain after neurotransplantation. Primordium development resulted in the building of a new structure with the same imaging features as the corresponding mature structure, combined with short- and long-distance targeted migration of neuroblasts. The results of this study support both the reconstructive potential of fetal tissue and the remarkably retained plasticity of adult brain. Further studies are necessary to assess the clinical efficacy of the human fetal striatal transplantation.

Development of human striatal anlagen after transplantation in a patient with Huntington's disease

Replacement of damaged neuronal population by fetal tissue transplantation represents a potential treatment for neurodegenerative diseases. Consistent success has been achieved with fetal striatal transplantation in Huntington's disease animal models and patients. We report the neo-generation of metabolically active tissue with striatum-like imaging features after transplantation of striatal primordia in a patient with Huntington's disease. This study represents the first “ in vivo” demonstration that a human striatal anlagen, transplanted into the adult human brain, is able to progress in its development and to generate a new anatomical structure in the host, without evidence of neoplasia or teratoma.

Long-term clinical and positron emission tomography outcome of fetal striatal transplantation in Huntington’s disease

Two patients with moderate Huntington’s disease (HD) received bilateral fetal striatal allografts. One patient demonstrated, for the first time, increased striatal D2 receptor binding, evident with 11C-raclopride positron emission tomography,...

Transplantation of human fetal striatal tissue in Huntington's disease: rationale for clinical studies.

Huntington's disease is a fatal neurological disorder characterized by chorea and deterioration in cognitive and neuropsychiatric function. Primary pathological changes are found in the striatum, where GABAergic neurons undergo degenerative changes. Local interneurons are relatively spared. Here, we describe the rationale for clinical trials of fetal striatal tissue transplantation for the treatment of Huntington's disease. Specifically, the reasons for utilizing tissue derived from the far lateral aspect of the lateral ventricular eminence as a source of striatal tissue will be discussed.

Chapter 18 Neural transplantation for the treatment of Huntington's disease

Neural transplantation is applicable in the treatment of Huntington's disease (HD). At this time, there is only preliminary evidence of safety, tolerability, and efficacy of fetal striatal transplantation for the treatment of HD. The safety profile may differ adversely from similar transplant programs for the treatment of Parkinson's disease, because of the atrophy associated with HD that may predispose patients to the development of subdural hematomas after surgically induced cerebrospinal fluid (CSF) loss. Although graft survival has been demonstrated at autopsy, there is significant gliosis associated with late-stage HD, which may make transplantation in late-stage patients less favorable. Human fetal striatal grafts in both rodent models and patients with HD are capable of receiving appropriate neuritic in growth from the host brain. It remains unproven if striatal grafts in patients with HD are similarly capable of extending projections over the distances necessary to reach appropriate target areas, as seen in animal allograft transplant models of HD. There is currently no agreement on the optimal way to dissect human fetal tissue for transplantation purposes.

Stem cell technology for basic science and clinical applications.

In the adult mammalian central nervous system (CNS), most of the mechanisms responsible for cell proliferation and migration are shut off; thus, the capacities for self-repair and cellular replacement are greatly diminished. Observations that cell division continues in some regions of the adult brain and some resulting cells become neurons prompted attempts to identify the progenitor cells responsible for both embryonic and postnatal neural developments. The term stem cells refers to a population of cells that is capable of extended self-renewal and the ability to generate multilineage (neurons and glia) cell types (Figure). The growing interest in the isolation and propagation of stem cells and studying stem cell biology is driven by 2 goals. The first goal is to establish an in vitro system to ellucidate the fate pathways of individual neural progenitors. Such a system can be used to determine signaling molecules controlling the generation of specific neural cell lineages and to dissect cellular mechanisms underlying the progressive processes of commitment, fate determination, and differentiation during neural development. The second goal is to use such cultured, well-characterized cells for therapeutic applications in the treatment of neurologic and neurodegenerative diseases. In many neurologic diseases, specific neural cell types or circuits degenerate. These losses may be due to genetic abnormalities of the diseased cell or may be due to the absence of enzymes, neurotransmitters, trophic factors or cofactors, or the presence of toxic substances or physical injury. Treatment of CNS disease or injury could focus on one or more steps leading to cell loss. Clinical trials show that neuron replacement for neurodegenerative diseases, such as Parkinson and Huntington diseases is feasible. Grafts of freshly dissected fetal substantia nigra have shown promising longterm clinical improvement in some patients with Parkinson disease. The improvements wereassociatedwiththesurvivalofthegrafts and dopaminergic reinnervation of the striatum. 1 Reports 2 of fetal striatal transplantation in patients with mild to severe Huntington disease suggest that neurotranplantation may improve some of the cognitive symptoms associated with the disease and may modify the course of the disease. Ex vivo gene therapy is an alternative approach that has been used in various ex

Bilateral Fetal Striatal Grafts in the 3-Nitropropionic Acid-Induced Hypoactive Model of Huntington’s Disease

We investigated the 3-nitropropionic acid (3-NP)–induced hypoactive model of Huntington’s disease (HD) to demonstrate whether fetal tissue transplantation can ameliorate behavioral deficits associated with a more advanced stage of HD. Twelve-week-old Sprague–Dawley rats were introduced to the 3-NP dosing regimen (10 mg/kg, i.p., once every 4 days for 28 consecutive days), and were then tested for general spontaneous locomotor activity in the Digiscan locomotor apparatus. All rats displayed significant hypoactivity compared to their pre-3-NP injection locomotor activity. Randomly selected rats then received bilateral intrastriatal solid grafts of fetal striatal (lateral ganglionic eminence, LGE) tissues from embryonic day 14 rat fetuses. Approximately 1/3 of each LGE in hibernation medium was infused into each lesioned host striatum. In control rats, medium alone was infused intrastriatally. A 3-mo posttransplant maturation period was allowed prior to locomotor activity testing. Animals receiving fetal LGE grafts exhibited a significant increase in locomotor activity compared to their post-3-NP injection activity or to the controls’ posttransplant activity. Surviving striatal grafts were noted in functionally recovered animals. This observation supports the use of fetal striatal transplants to correct the akinetic stage of HD. To the best of our knowledge, this is the first study that has investigated the effects of fetal striatal transplantation in a hypoactive model of HD.

Bilateral fetal striatal grafts in the 3-nitropropionic acid-induced hypoactive model of Huntington's disease.

We investigated the 3-nitropropionic acid (3-NP)-induced hypoactive model of Huntington's disease (HD) to demonstrate whether fetal tissue transplantation can ameliorate behavioral deficits associated with a more advanced stage of HD. Twelve-week-old Sprague-Dawley rats were introduced to the 3-NP dosing regimen (10 mg/kg, i.p., once every 4 days for 28 consecutive days), and were then tested for general spontaneous locomotor activity in the Digiscan locomotor apparatus. All rats displayed significant hypoactivity compared to their pre-3-NP injection locomotor activity. Randomly selected rats then received bilateral intrastriatal solid grafts of fetal striatal (lateral ganglionic eminence, LGE) tissues from embryonic day 14 rat fetuses. Approximately 1/3 of each LGE in hibernation medium was infused into each lesioned host striatum. In control rats, medium alone was infused intrastriatally. A 3-mo posttransplant maturation period was allowed prior to locomotor activity testing. Animals receiving fetal LGE grafts exhibited a significant increase in locomotor activity compared to their post-3-NP injection activity or to the controls' posttransplant activity. Surviving striatal grafts were noted in functionally recovered animals. This observation supports the use of fetal striatal transplants to correct the akinetic stage of HD. To the best of our knowledge, this is the first study that has investigated the effects of fetal striatal transplantation in a hypoactive model of HD.

Human fetal striatal transplantation in an excitotoxic lesioned model of Huntington's disease.

Human fetal striatal transplantation in an excitotoxic lesioned model of Huntington's disease.

Neuropsychological functioning following fetal striatal transplantation in Huntington's chorea: Three case presentations

Neurotransplantation has been proposed as a potential treatment for the neurodegenerative disorder of Huntington's disease (HD), which currently has no effective therapy. While patients with Parkinson's disease have received neurotransplantation, until recently no HD patients have undergone transplantation for HD with standardized evaluations of their progress following surgery. The current report presents the cognitive changes in three patients with HD who underwent bilateral transplantation of human fetal striatal tissue. As part of the pre- and postsurgical evaluation, all three patients were administered a neuropsychological battery sensitive to the cognitive effects of HD within 2 mo prior to surgery and at 4–6 mo following transplantation. Four to 6 mo subsequent to surgery, all patients demonstrated increased scores on some measures of cognitive functioning. However, the pattern of changes was not uniform across subjects. These findings suggest that fetal striatal transplantation may improve some of the cognitive symptoms associated with HD in the three reported patients.

Development of the human striatum: Implications for fetal striatal transplantation in the treatment of Huntington's disease

Fetal neural transplantation has recently been demonstrated to ameliorate motor and other behavioral deficits in animal models of Huntington's disease, and reconstruct many of the damaged striatal circuits. However, there has been significant variability in the histological appearance of these grafts, most likely related to differences of the regions of dissection of the donor tissue. Selective dissection and transplantation of the lateral ventricular eminence in rodents has resulted in grafts consisting of primarily striatal-like tissue. This data, combined with data from our own and other laboratories has led to a description of the development of the human striatum, with a particular emphasis on the relevance of human striatal development to the field of fetal tissue transplantation for the treatment of Huntington's disease. If the goal of transplantation is to graft GABAergic striatal projection neurons, it is our impression that optimal grafting results will occur when transplants are derived from the lateral ventricular eminence and the lateral aspect of the body of the ventricular eminence anterior to the foramen of Monro. Optimal results are likely to occur when donor ages range from Stage 19 to 23, with possible graft success when donor age extends to as late as postovulatory week 22.

Development of the human striatum: implications for fetal striatal transplantation in the treatment of Huntington's disease.

Fetal neural transplantation has recently been demonstrated to ameliorate motor and other behavioral deficits in animals models of Huntington's disease, and reconstruct many of the damaged striatal circuits. However, there has been significant variability in the histological appearance of these grafts, most likely related to differences of the regions of dissection of the donor tissue. Selective dissection and transplantation of the lateral ventricular eminence in rodents has resulted in grafts consisting of primarily striatal-like tissue. This data, combined with data from our own and other laboratories has led to a description of the development of human striatum, with a particular emphasis on the relevance of human striatal development to the field of fetal tissue transplantation for the treatment of Huntington's disease. If the goal of transplantation is to graft GABAergic striatal projection neurons, it is our impression that optimal grafting results will occur when transplants are derived from the lateral ventricular eminence and the lateral aspect of the body of the ventricular eminence anterior to the foramen of Monro. Optimal results are likely to occur when donor ages range from Stage 19 to 23, with possible graft success when donor age extends to as late as postovulatory week 22.