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S Saporta

Publications and source records attributed to S Saporta.

At least 37 records · Page 2Linked to original sources
PubMed2000

Adult bone marrow stromal cells differentiate into neural cells in vitro.

Bone marrow stromal cells (BMSC) normally give rise to bone, cartilage, and mesenchymal cells. Recently, bone marrow cells have been shown to have the capacity to differentiate into myocytes, hepatocytes, and glial cells. We now demonstrate that human and mouse BMSC can be induced to differentiate into neural cells under experimental cell culture conditions. BMSC cultured in the presence of EGF or BDNF expressed the protein and mRNA for nestin, a marker of neural precursors. These cultures also expressed glial fibrillary acidic protein (GFAP) and neuron-specific nuclear protein (NeuN). When labeled human or mouse BMSC were cultured with rat fetal mesencephalic or striatal cells, a small proportion of BMSC-derived cells differentiated into neuron-like cells expressing NeuN and glial cells expressing GFAP.

Animals↗
PubMed2000

In vitro and in vivo characterization of hNT neuron neurotransmitter phenotypes.

The hNT neuron exhibits many characteristics of neuroepithelial precursor cells, making them an excellent model to study neuronal plasticity in vitro and in vivo. These cells express a number of neurotransmitters in vitro, including dopamine, gamma-aminobutyric acid and acetylcholine. However, there have been few reports of the neurotransmitters that hNT neurons express in vivo. The present study examined whether hNT neurons express the same neurotransmitters in vivo as they do in vitro. First, the expression of tyrosine hydroxylase (TH), glutamic acid decarboxylase (GAD), choline acetyltransferase (ChAT) and the human specific nuclear marker NuMA by hNT neurons was confirmed. Nineteen normal animals were then transplanted with 80,000 hNT neurons aimed at the striatum, hippocampus or cerebral cortex. Five additional animals received injections of medium. All animals received daily intraperitoneal injections of cyclosporine (10 mg/kg) and survived 30 days. Sections through the transplants were examined for NuMA-positive hNT neurons, and for the presence of the three neurotransmitter markers: TH, GAD and ChAT. The hNT neurons were found in the striatum and cortex. Of the hNT neurons found within the rat striatum, 33% were ChAT-positive. In the cortex, only 4% of the neurons expressed ChAT. No GAD-positive hNT neurons were detected at either site. No NuMA-positive neurons were found in the hippocampus. The implanted hNT neurons did not induce activation of astrocytes as determined by immunocytochemistry for glial fibrillary acidic protein (GFAP). Moreover, no hNT neuron was found to express GFAP in vivo. Together, these data suggest that the hNT neurons engraft in the new host tissue, maintain their neuronal identity and may be guided in differentiation according to local environmental cues.

Animals↗
PubMed1999

Sertoli cells enhance the survival of co-transplanted dopamine neurons.

One of the major issues in neural transplantation is the low survival rate (<5%) of transplanted dopamine (DA) neurons [3]. Recently it has been shown that it is possible to enhance the survival of these neurons, which in turn may decrease the amount of tissue that is required for each transplantation patient. The present paper demonstrates a novel approach for enhancing neuronal survival by co-transplantation of neuronal tissue with Testis-derived Sertoli cells (SC). This strategy could improve neuronal survival through the provision of trophic support.

Animals↗
PubMed1999

Sertoli cells decrease microglial response and increase engraftment of human hNT neurons in the hemiparkinsonian rat striatum.

Sertoli cells (SCs) provide immune protection and nutritive support to the developing germ cells in the testis. Sertoli cells have also been shown to provide immune protection to islets transplanted outside the testes. In this study, the ability of these cells to diminish the infiltration/activation of microglia into a neural graft implanted in the lesioned striatum of a hemiparkinsonian rat was investigated. Human neuron-like cells (hNT neurons) were implanted either alone or in combination with rat SCs. Three months later, the animals were sacrificed and immunohistochemistry was performed to determine the survival of the xenografted neurons as well as microglial infiltration/activation. Cotransplantation of the SCs with the hNT neurons increased graft survival and was associated with an increase in graft size. Furthermore, there were fewer microglia present in the grafted tissue of the cotransplantation groups. These results show that SCs retain their immunosuppressive ability even within the brain. As immune responses to grafted neural tissue within the central nervous system become better understood, this ability of the SCs to provide localized immunosuppression to the transplanted tissue may become more important. This is particularly true as the search for alternative sources of neural tissue to treat neurodegenerative diseases expands to encompass other species.

Animals↗
PubMed1999

Lithium chloride induces the expression of tyrosine hydroxylase in hNT neurons.

In the present study, several doses of lithium chloride were tested for their ability to induce the expression of tyrosine hydroxylase (TH) in neurons derived from a human teratocarcinoma cell line (hNT) after 5 and 10 days in vitro (DIV). Following immunocytochemical staining for tyrosine hydroxylase, the percentage of TH-positive neurons was determined and morphometric analysis, including mean soma profile area and neuritic length, was performed. hNT neurons responded to lithium treatment in a dose-dependent manner. In 5 DIV, the most effective dose of lithium chloride (1.0 mM) increased the number of TH-positive neurons approximately sixfold. In addition, both TH-positive hNT neuron mean soma profile area and neurite length were significantly larger than controls by 60 and 70%, respectively. Moreover, even after withdrawal of lithium chloride on day 5, the number of TH-positive neurons in 10 DIV cultures remained significantly increased. These data suggest that hNT cells are indeed responsive to lithium exposure and may serve as a continual source of TH-expressing neurons in new therapeutic approaches to degenerative brain disease.

Cell Differentiation↗
PubMed1999

Neural transplantation of human neuroteratocarcinoma (hNT) neurons into ischemic rats. A quantitative dose-response analysis of cell survival and behavioral recovery.

Transplantation of fetal neuronal tissue has been used successfully to ameliorate symptoms of neurodegenerative disease in animals and humans. This technique has recently been extended as an experimental treatment for ischemic brain damage. However, due to ethical issues with the use of fetal cells for the treatment of any human disease, there has been a concerted effort to find alternative graft sources for neural transplantation. The human neuroteratocarcinoma neuron cell is derived from an embryonal teratocarcinoma cell line that can be differentiated into post-mitotic neurons. Neural transplantation of human neuroteratocarcinoma neurons has recently been shown to produce behavioral amelioration of symptoms in rats with ischemia-induced injury. The present study was undertaken to: (i) determine the minimum effective number of transplanted human neuroteratocarcinoma neurons required for amelioration of ischemia-induced behavioral dysfunction; and (ii) quantify the survival of human neuroteratocarcinoma neurons in vivo. Transplants of 0, 5, 10, 20, 40, 80 or 160 x 10(3) human neuroteratocarcinoma neurons were made into rats that sustained ischemic damage. Animals that received 40, 80 or 160 x 10(3) human neuroteratocarcinoma neurons demonstrated a dose-dependent improvement in performance of both the passive avoidance and elevated body swing tests. At the conclusion of behavioral testing, human neuroteratocarcinoma neurons were identified in paraffin sections with human neural cell adhesion molecule MOC-1 and human neurofilament antibodies. Transplants of 80 or 160 x 10(3) human neuroteratocarcinoma neurons demonstrated a 12-15% survival of human neuroteratocarcinoma neurons in the graft, while transplants of 40 x 10(3) human neuroteratocarcinoma neurons demonstrated a 5% survival. Transplantation of human neuroteratocarcinoma neurons ameliorated behavioral deficits produced by ischemic damage. The human neuroteratocarcinoma neuron, additionally, showed greater survival than that reported for fetal cells when transplanted into the brain. Therefore, this readily available cell may prove to be an excellent candidate for the treatment of ischemic damage in human patients.

Animals↗
PubMed1998

Viability and survival of hNT neurons determine degree of functional recovery in grafted ischemic rats.

We recently reported behavioral improvements following intrastriatal transplantation of cryopreserved cultured human neuroteratocarcinoma-derived cells (hNT neurons) in rats with cerebral ischemia induced by occlusion of the middle cerebral artery. In the present study, the viability and survival of hNT neurons were evaluated immediately prior to the transplantation surgery and at 3 months post-transplantation in ischemic rats. Cryopreserved hNT neurons were routinely thawed, and trypan blue exclusion viability counts revealed 52-95% viable hNT neurons before transplantation. Monthly behavioral tests, starting at 1 month and extending to 3 months post-transplantation, revealed that ischemic animals that were intrastriatally transplanted with hNT neurons (approximately 40000) and treated with an immunosuppressive drug displayed normalization of asymmetrical motor behavior compared with ischemic animals that received medium alone. Within-subject comparisons of cell viability and subsequent behavioral changes revealed that a high cell viability just prior to transplantation surgery correlated highly with a robust and sustained functional improvement in the transplant recipient. Furthermore, histological analysis of grafted brains revealed a positive correlation between number of surviving hNT neurons and degree of functional recovery. In concert with similar reports on fetal tissue transplantation, we conclude that high cell viability is an important criterion for successful transplantation of cryopreserved neurons derived from cell lines to enhance graft-induced functional effects.

Animals↗
PubMed1998

Preparation of cell suspensions for co-transplantation: methodological considerations.

The purpose of the current study was to determine the optimal strategy for preparing cell suspensions for co-transplantation. In the first experiment, the number of Sertoli cell (SC) aggregates and the number of tyrosine hydroxylase positive neurons were compared over time when cell suspensions of Sertoli or ventral mesencephalic cells were kept as a co-suspension mixed at 0 h. Cells from each suspension were dispensed onto glass slides in a manner similar to transplantation. When dispensed in this manner, the number of SC aggregates and TH-positive neurons decreased over 4 h. In experiment 2, the cell suspensions were mixed just prior to injection at each of four timepoints, the number of aggregates and TH neurons was consistent over time. Clearly this latter strategy resulted consistent recovery of both cell types for transplants up to 3 h after suspension preparation.

Animals↗
PubMed1998

Intrastriatal transplantation of rat adrenal chromaffin cells seeded on microcarrier beads promote long-term functional recovery in hemiparkinsonian rats.

Possible biologic treatments for Parkinson's disease, a disorder caused by the deterioration of dopaminergic neurons bridging the nigrostriatal system, have recently focused on fetal cell transplantation. Because of ethical and tissue availability issues concerning fetal cell transplantation, alternative cell sources are being developed. The adrenal medulla has been used as a cell transplant source because of the capacity of the cells to provide catecholamines and to transform into a neuronal phenotype. However, adrenal tissue transplants have shown limited success, primarily because of their lack of long-term viability. Recently, seeding adrenal chromaffin cells on microcarrier beads has been shown to enhance the cell viability following neural transplantation. In the present study, we further investigated whether transplantation of rat adrenal chromaffin cells seeded on microcarrier beads into the striatum of 6-hydroxydopamine-induced hemiparkinsonian rats would result in a sustained functional recovery. Behavioral tests using the apomorphine-induced rotational and elevated body swing tests up to 12 months posttransplantation revealed a significant behavioral recovery in animals that received adrenal chromaffin cells seeded on microcarrier beads compared to animals that received adrenal chromaffin cells alone, medium alone, or beads alone. Histological examination of tissue at 14 months posttransplantation revealed evidence of tyrosine hydroxylase-positive cells and an on-going glial response in animals transplanted with adrenal chromaffin cells seeded on microcarrier beads, in contrast to absence of such immunoreactive responses in the other groups. These findings support a facilitator role for microcarrier beads in transplantation of adrenal chromaffin cells or other cells that are easily rejected by the CNS.

Adrenal Glands↗
PubMed1997

Survival of rat and porcine Sertoli cell transplants in the rat striatum without cyclosporine-A immunosuppression.

The use of cyclosporine-A (CsA) immunosuppression for neural transplantation has become the treatment of choice for ameliorating host-graft rejection responses in human and animal transplant studies. However, the cytotoxic effects of CsA have warranted a search for alternative methods of protecting neural transplants. Sertoli cells produce an immunosuppressant factor, Fas ligand (Fas-L), that may provide the testis with its immunoprivileged status. Therefore, it has recently been suggested that these cells may be useful in producing localized immunosuppression for transplants. If Sertoli cells do produce localized immunosuppression, then it should be possible to successfully transplant Sertoli cells without additional immunosuppression following transplant surgery. The present study was undertaken to determine whether rat or porcine Sertoli cells transplanted into rat brain would survive for an extended period of time without CsA immunosuppression. Isolated rat or porcine Sertoli cells prelabeled with DiI were transplanted into normal rat brain. We report that both rat Sertoli cell allografts and porcine Sertoli cell xenografts survived for at least 2 months posttransplantation into the rat brain without CsA immunosuppression, indicating that these grafts were capable of producing sufficient localized immunosuppression to survive at the site of transplant without additional systemic immunosuppression.

Animals↗
PubMed1997

Intracerebral transplantation of testis-derived sertoli cells promotes functional recovery in female rats with 6-hydroxydopamine-induced hemiparkinsonism.

Recently, we demonstrated amelioration of behavioral deficits associated with 6-hydroxydopamine-induced hemiparkinsonism by transplanting rat testis-derived Sertoli cells into adult male rat brains. In the present study, we used adult female hemiparkinsonian rats to investigate whether the beneficial effects of transplantation of Sertoli cells may be differentially affected by gender of the animal transplant recipient. At 1 month posttransplantation, animals transplanted with Sertoli cells showed functional recovery as revealed by significant reductions in apomorphine-induced rotational behavior and asymmetrical elevated body swing behavior. Control animals that received medium alone did not display any visible behavioral recovery. These results suggest that transplantation of Sertoli cells is not male hormone-dependent and further support the use of these cells as a graft source for Parkinson's disease and other neurological disorders.

Animals↗
PubMed1997

Testis-derived Sertoli cells have a trophic effect on dopamine neurons and alleviate hemiparkinsonism in rats.

Neural tissue transplantation has become an alternative treatment for Parkinson's disease (PD) and other neurodegenerative disorders. The clinical use of neural grafts as a source of dopamine for Parkinson's disease patients, although beneficial, is associated with logistical and ethical issues. Thus, alternative graft sources have been explored including polymer-encapsulated cells and nonneural cells (that is, adrenal chromaffin cells) or genetically modified cells that secrete dopamine and/or trophic factors. Although progress has been made, no current alternative graft source has ideal characteristics for transplantation. Emerging evidence suggests the importance of trophic factors in enhancing survival and regeneration of intrinsic dopaminergic neurons. It would be desirable to transplant cells that are readily available, immunologically accepted by the central nervous system and capable of producing dopamine and/or trophic factors. Sertoli cells have been shown to secrete CD-95 ligand and regulatory proteins, as well as trophic, tropic, and immunosuppressive factors that provide the testis, in part, with its "immunoprivileged" status. The present study demonstrated that transplantation of rat testis-derived Sertoli cells into adult rat brains ameliorated behavioral deficits in rats with 6-hydroxydopamine-induced hemiparkinsonism. This was associated with enhanced tyrosine hydroxylase (TH) immunoreactivity in the striatum in the area around the transplanted Sertoli cells. Furthermore, in vitro experiments demonstrated enhanced dopaminergic neuronal survival and outgrowth when embryonic neurons were cultured with medium in which rat Sertoli cells had been grown. Transplantation of Sertoli cells may provide a useful alternative treatment for PD and other neurodegenerative disorders.

Animals↗
PubMed1996

Testis-derived Sertoli cells survive and provide localized immunoprotection for xenografts in rat brain.

Transplantation of neural tissue into the mammalian central nervous system has become an alternative treatment for neurodegenerative disorders such as Parkinson's disease. Logistical and ethical problems in the clinical use of human fetal neural grafts as a source of dopamine for Parkinson's disease patients has hastened a search for successful ways to use animal dopaminergic cells for human transplantation. The present study demonstrates that transplanted testis-derived Sertoli cells into adult rat brains survive. Furthermore, when cotransplanted with bovine adrenal chromaffin cells (xenograft), Sertoli cells produce localized immunoprotection, suppress microglial response and allow the bovine cells to survive in the rat brain without continuous systemic immunosuppressive drugs. These novel features support Sertoli cells as a viable graft source for facilitating the use of xenotransplantation for Parkinson's disease and suggest their use as facilitators, (i.e., localized immunosuppression) for cell transplantation in general.

Animals↗
PubMed1996

CNS immunological modulation of neural graft rejection and survival.

Neural transplantation therapy as a possible alternative treatment for neurological movement disorders, such as in Parkinson's disease (PD), has accentuated research interest on the immune status of the central nervous system (CNS). Most animal studies concerned with neural transplantation for the treatment of PD have utilized dopamine (DA) neurons from tissues of the embryonic ventral mesencephalon. Rat embryonic DA neurons, grafted either as solid blocks or dissociated into a cell suspension and stereotaxically injected intraparenchymally into a rat lesion model of PD, have been shown to survive and form connections with the host brain, and ameliorate the behavioral deficits of PD. Similarly, studies on nonhuman primate models of PD provide considerable support for neural transplantation of DA neurons as an experimental clinical procedure for the treatment of PD. To this end, experimental clinical trials have been centered upon transplantation of the embryonic ventral mesencephalic cells for PD patients. Although not conclusive, the findings from clinical studies have provided some evidence that most patients with marked increases in fluorodopa uptake (indicating graft survival) have been immunosuppressed. Furthermore, immune reactions have been observed in rats xenografted with human embryonic tissue. Of note, embryonic ventral mesencephalic tissues compared to adult tissues produce better morphological and long-lasting behavioral amelioration of the neurobehavioral deficits of PD, thus advocating the use of grafts from young donors (embryo) to circumvent the CNS immune rejection. The possible graft rejection due to CNS immune reactions, coupled with the social and ethical problems surrounding the use of embryonic neural tissue, and the logistical problems concerning tissue availability have prompted the development of alternative sources of DA-secreting cells. To circumvent these obstacles, several methods have been suggested including the use of immunosuppressants such as Cyclosporine-A, transplantation of autografts, polymer-encapsulated DA-secreting cells, co-culturing and co-transplantation of DA-secreting cells with microcarrier beads, with Sertoli cells, or with fragments of a monoclonal antibody that can mask the MHC class I antigens, and genetically modifying cells that can withstand CNS immune reactions. Some of these techniques allow transplantation of allograft (same species transplantation), or even xenograft (cross species transplantation) without immunosuppression of the recipient. We discuss recent CNS immunosuppression techniques that pose some promise for enhanced survival of neural grafts. When possible, advantages and disadvantages of each method are presented. Hopefully, such critical analysis of different immunosuppression techniques will produce innovated ideas that will lead to a better understanding of CNS immune response and its modulatory function on graft rejection and survival.

Adrenal Medulla↗
PubMed1994

Distributed actions and dynamic associations in respiratory-related neuronal assemblies of the ventrolateral medulla and brain stem midline: evidence from spike train analysis.

1. Considerable evidence indicates that neurons in the brain stem midline and ventrolateral medulla participate in the control of breathing. This work was undertaken to detect and evaluate evidence for functional links that coordinate the parallel operations of neurons distributed in these two domains. 2. Data were from 51 Dial-urethan-anesthetized, bilaterally vagotomized, paralyzed, artificially ventilated cats. Planar arrays of tungsten microelectrodes were used to monitor simultaneously spike trains in two or three of the following regions: n. raphe obscurus-n. raphe pallidus, n. raphe magnus, rostral ventrolateral medulla, and caudal ventrolateral medulla. Efferent phrenic nerve activity was recorded to indicate the phases of the respiratory cycle. Electrodes in the ventral spinal cord (C3) were used in antidromic stimulation tests for spinal projections of neurons. 3. Spike trains of 1,243 neurons were tested for respiratory modulated firing rates with cycle-triggered histograms and an analysis of variance with the use of a subjects-by-treatments experimental design. Functional associations were detected and evaluated with cross-correlograms, snowflakes, and the gravity method. 4. Each of 2,310 pairs of neurons studied included one neuron monitored within 0.6 nm of the brain stem midline and a second cell recorded in the ventrolateral medulla; 117 of these pairs (5%) included a neuron with a spinal projection, identified with antidromic stimulation methods, that extended to at least the third cervical segment. Short-time scale correlations were detected in 110 (4.7%) pairs of neurons. Primary cross-correlogram features included 40 central peaks, 47 offset peaks, 4 central troughs, and 19 offset troughs. 5. In 14 data sets, multiple short-time scale correlations were found among three or more simultaneously recorded neurons distributed between both midline and ventrolateral domains. The results suggested that elements of up to three layers of interneurons were monitored simultaneously. Evidence for concurrent serial and parallel regulation of impulse synchrony was detected. Gravitational representations demonstrated respiratory-phase dependent synchrony among neurons distributed in both brain stem regions. 6. The results support a model of the brain stem respiratory network composed of coordinated distributed subassemblies and provide evidence for several hypotheses. 1) Copies of respiratory drive information from rostral ventrolateral medullary (RVLM) respiratory neurons are transmitted to midline neurons. 2) Midline neurons act on respiratory-related neurons in the RVLM to modulate phase timing. 3) Impulse synchrony of midline neurons is influenced by concurrent divergent actions of both midline and ventrolateral neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Evaluation of blood-brain barrier permeability and the effect of interferon in mouse glioma model.

The aim of this study was to evaluate whether interferon [IFN] can affect intracerebrally grown glioma and how alteration of the blood-brain barrier [BBB] may influence this effect. An intracerebrally implanted glioma G-26 (G-26) mouse brain-tumor model was developed and used in these studies. Histological characterization of this intracerebrally grown tumor revealed its anaplastic character. The astrocytic origin of G-26 was evidenced by glial fibrillary acidic protein staining and electron microscopic visualization of glial filaments. A study of tumor progression and animal survival showed development of a well defined tumor nodule within approximately seven days after the implantation. The median animal survival time was 27 +/- 3.8 days. The integrity of the blood-brain barrier [BBB] within the tumor was evaluated by the intravenous injection of horseradish peroxidase at days 3, 7, 10 and 20 after brain tumor implant and compared to 'sham' controls. The tumor-induced BBB alteration was progressive from day 3 to day 20. Glioma-26 subcutaneously passed in C57BL/6 mice was also continuously cultured in vitro. Its proliferation was inhibited by homologous mouse interferon alpha/beta [MuIFN alpha/beta] but not by human interferon alpha lymphoblastoid or human interferon beta. The in vivo studies of G-26 glioma treatment with MuIFN alpha/beta were performed using single bolus of IFN in osmotically altered animals or slow IFN infusion through osmotic micro-pumps. The slow infusion of IFN had no effect on animal survival. However, a statistically significant increase in animal survival was observed after single bolus IFN treatment following osmotic BBB alteration.

Animals↗