MOG-IgG in primary and secondary chronic progressive multiple sclerosis: a multicenter study of 200 patients and review of the literature.

BACKGROUND: Antibodies to human full-length myelin oligodendrocyte glycoprotein (MOG-IgG) as detected by new-generation cell-based assays have recently been described in patients presenting with acute demyelinating disease of the central nervous system, including patients previously diagnosed with multiple sclerosis (MS). However, only limited data are available on the relevance of MOG-IgG testing in patients with chronic progressive demyelinating disease. It is unclear if patients with primary progressive MS (PPMS) or secondary progressive MS (SPMS) should routinely be tested for MOG-IgG. OBJECTIVE: To evaluate the frequency of MOG-IgG among patients classified as having PPMS or SPMS based on current diagnostic criteria. METHODS: For this purpose, we retrospectively tested serum samples of 200 patients with PPMS or SPMS for MOG-IgG using cell-based assays. In addition, we performed a review of the entire English language literature on MOG-IgG published between 2011 and 2017. RESULTS: None of 139 PPMS and 61 SPMS patients tested was positive for MOG-IgG. Based on a review of the literature, we identified 35 further MOG-IgG tests in patients with PPMS and 55 in patients with SPMS; the only reportedly positive sample was positive just at threshold level and was tested in a non-IgG-specific assay. In total, a single borderline positive result was observed among 290 tests. CONCLUSION: Our data suggest that MOG-IgG is absent or extremely rare among patients with PPMS or SPMS. Routine screening of patients with typical PPMS/SPMS for MOG-IgG seems not to be justified.

Monocytes are essential for the neuroprotective effect of human cord blood cells following middle cerebral artery occlusion in rat.

Systemic administration of human umbilical cord blood (HUCB) mononuclear cells (MNC) following middle cerebral artery occlusion (MCAO) in the rat reduces infarct size and, more importantly, restores motor function. The HUCB cell preparation is composed of immature T-cells, B-cells, monocytes and stem cells. In this study we examined whether the beneficial effects of HUCB injection were attributable to one of these cell types. Male Sprague Dawley rats underwent permanent MCAO followed 48 h later by intravenous administration of HUCB MNC preparations depleted of either CD14(+) monocytes, CD133(+) stem cells, CD2(+) T-cells or CD19(+) B cells. Motor function was measured prior to MCAO and 30 days post-stroke. When CD14(+) monocytes were depleted from the HUCB MNC, activity and motor asymmetry were similar to the MCAO only treated animals. Monocyte depletion prevented HUCB cell treatment from reducing infarct size while monocyte enrichment was sufficient to reduce infarct size. Administration of monocyte-depleted HUCB cells did not suppress Iba1 labeling of microglia in the infarcted area relative to treatment with the whole HUCB preparation. These data demonstrate that the HUCB monocytes provide the majority of the efficacy in reducing infarct volume and promoting functional recovery.

Treatment with afobazole at delayed time points following ischemic stroke improves long-term functional and histological outcomes.

There is currently a significant lack of therapeutic options for acute ischemic stroke, and no drug has been approved for treating patients at delayed time points (≥6h post-stroke). Afobazole, an anxiolytic currently used clinically in Russia, has been shown to reduce neuronal and glial cell injury in vitro following ischemia. Experiments using the permanent middle cerebral artery occlusion (MCAO) rat model were carried out to determine if afobazole can reduce ischemic stroke damage in vivo and expand the therapeutic window for stroke treatment. Post-stroke (24h) application of afobazole (0.3-3mg/kg) significantly decreased infarct volume at 96h post-surgery, as determined by Fluoro-Jade and NeuN staining of brain sections. Moreover, afobazole helped preserve both the levels and normal histological distribution of myelin basic protein, indicating a reduction in white matter injury. A time-dependence study showed that either pre-treatment or treatment started 6 to 48h post-stroke with the drug yields improved outcomes at 96h. The decrease in infarct volume produced by afobazole was blocked by the application of either a σ-1 (BD 1063, 30mg/kg) or a σ-2 (SM-21, 1mg/kg) antagonist, indicating that both receptor subtypes are involved in the effects of afobazole. Treatment with afobazole starting at 24h post-stroke resulted in enhanced survival one month following surgery. Behavioral testing of animals 28-32days post-surgery using the elevated body swing and forelimb grip-strength tests revealed that treatment with afobazole starting 24h post-stroke significantly reduces behavioral deficits caused by ischemic stroke. The increase in survival and improved functional outcomes are accompanied by a reduction in infarct volume, as determined by thionin staining of brain sections. Taken together, our data support the use of afobazole as a post-stroke pharmacological agent to expand the current therapeutic window.

Human umbilical cord blood cells alter blood and spleen cell populations after stroke.

The human umbilical cord blood (HUCB) mononuclear cell (MNC) fraction is a mixed population of cells that induces functional repair in rodent models of stroke when injected intravenously (i.v.). The transplanted cells are found in the infarcted hemisphere and the spleen. The goal of this project was to determine the nature of the interaction between the HUCB MNCs cells and splenic immune cells. Male Sprague Dawley rats underwent permanent middle cerebral artery occlusion (MCAO) and received i.v. injection of either vehicle (MCAO only), HUCB MNCs or MNCs depleted of CD14+ monocytes, CD133+ stem cells or CD19+ B cells 48 hours post-stroke. At 72 hours post-MCAO, the animals were euthanized and the spleens and blood MNCs harvested for flow cytometry and mitogen proliferation assays. All HUCB cell preparations decreased the percentage of T cells in the spleen and monocytes in the blood (p < 0.05). MNCs depleted of CD14+ and CD19+ decreased the percentage of macrophage (p < 0.001), while CD133 depleted MNCs increased the percentage of macrophage in spleen (p < 0.001); MNC did not alter the macrophage population from the level observed after MCAO. Only HUCB MNC significantly decreased Concanavalin A (ConA)-induced T cell stimulation (p < 0.05). These results suggest that the effects of HUCB MNC in the spleen are not due to a single HUCB population, but the interaction of all the subpopulations together.

Cord blood administration induces oligodendrocyte survival through alterations in gene expression.

Oligodendrocytes (OLs), the predominant cell type found in cerebral white matter, are essential for structural integrity and proper neural signaling. Very little is known concerning stroke-induced OL dysfunction. Our laboratory has shown that infusion of human umbilical cord blood (HUCB) cells protects striatal white matter tracts in vivo and directly protects mature primary OL cultures from oxygen glucose deprivation (OGD). Microarray studies of RNA prepared from OL cultures subjected to OGD and treated with HUCB cells showed an increase in the expression of 33 genes associated with OL proliferation, survival, and repair functions, such as myelination. The microarray results were verified using quantitative RT-PCR for the following eight genes: U2AF homology motif kinase 1 (Uhmk1), insulin-induced gene 1 (Insig1), metallothionein 3 (Mt3), tetraspanin 2 (Tspan2), peroxiredoxin 4 (Prdx4), stathmin-like 2 (Stmn2), myelin oligodendrocyte glycoprotein (MOG), and versican (Vcan). Immunohistochemistry showed that MOG, Prdx4, Uhmk1, Insig1, and Mt3 protein expression were upregulated in the ipsilateral white matter tracts of rats infused with HUCB cells 48h after middle cerebral artery occlusion (MCAO). Furthermore, promoter region analysis of these genes revealed common transcription factor binding sites, providing insight into the shared signal transduction pathways activated by HUCB cells to enhance transcription of these genes. These results show expression of genes induced by HUCB cell therapy that could confer oligoprotection from ischemia.

Delayed treatments for stroke influence neuronal death in rat organotypic slice cultures subjected to oxygen glucose deprivation.

A major limitation of current stroke therapies is the need to treat candidate patients within 3 h of stroke onset. Human umbilical cord blood cell (HUCBC) and the sigma receptor agonist 1,3, di-o-tolylguanidine (DTG) administration both caused significant reductions in brain damage in the rat middle cerebral artery occlusion model of stroke when administered at delayed timepoints. In vivo, these treatments suppress the infiltration of peripheral lymphocytes into the brain in addition to decreasing neurodegeneration. An ex vivo organotypic slice culture (OTC) model was utilized to characterize the efficacy of these treatments in mitigating neurodegeneration in ischemic brain tissue in the absence of the peripheral immune system. Slice cultures subjected to oxygen glucose deprivation (OGD) had significantly elevated levels of degenerating neurons and microglial nitric oxide production when compared to their normoxic counterparts. In cultures subjected to OGD, HUCBC but not DTG treatment reduced the number of degenerating neurons and the production of microglial derived nitric oxide back to levels detected in normoxic controls. These data show that HUCBC treatment can mediate direct neuroprotection and suppress innate inflammation in ischemic brain tissue in the absence of the peripheral immune system, whereas DTG requires peripheral effects to mediate neuroprotection. These experiments yield insight into the mechanisms by which these neuroprotective treatments function at delayed timepoints following stroke.

Environmental properties of long-chain alcohols. Part 2: Structure-activity relationship for chronic aquatic toxicity of long-chain alcohols.

Daphnia magna reproduction tests were performed with C(10), C(12), C(14) and C(15) alcohols to establish a structure-activity relationship of chronic effects of long-chain alcohols. The data generation involved substantial methodological efforts due to the exceptionally rapid biodegradability of the test substances and the need to test as close as possible to their water solubility limits. Test concentrations were determined by GC-MS before and after test solution renewal. Whereas apparent toxicity based on survival and reproduction increased with increasing C-chain lengths up to C(14), observations of toxicity to C(15) alcohol were not in line with lower chain lengths due to the lack of toxicity below the level of water solubility. When omitting C(15), the slope of most (Q)SARs approach -1, being consistent with the expectation of a non-polar narcotic mode of action. Further testing at higher chain lengths is not sensible due to progressively lower solubility, at remaining biodegradability. Effects on mortality and reproduction are not expected below the level of water solubility.

Human umbilical cord blood cells directly suppress ischemic oligodendrocyte cell death.

Previous reports have shown that human umbilical cord blood cells (HUCBCs) administered intravenously 48 hr following middle cerebral artery occlusion reduce infarct area and behavioral deficits of rodents. This cellular therapy is potently neuroprotective and antiinflammatory. This study investigates the effect of HUCBC treatment on white matter injury and oligodendrocyte survival in a rat model of ischemia. Intravenous infusion of 10(6) HUCBCs 48 hr poststroke reduced the amount of white matter damage in vivo as seen by quantification of myelin basic protein staining in tissue sections. To determine whether HUCBC treatment was protective via direct effects on oligodendrocytes, cultured oligodendrocytes were studied in an in vitro model of oxygen glucose deprivation. Active caspase 3 immunohistochemistry and the lactate dehydrogenase assay for cytotoxicity were used to determine that HUCBCs provide protection to oligodendrocytes in vitro. Based on these results, it is likely that HUCBC administration directly protects oligodendrocytes and white matter. This effect is likely to contribute to the increased behavioral recovery observed with HUCBC therapy.

Assessment of the environmental risk of long-chain aliphatic alcohols.

An environmental assessment of long-chain alcohols (LCOH) has recently been conducted under the OECD SIDS High Production Volume (HPV) Program via the Global International Council of Chemical Associations (ICCA) Aliphatic Alcohols Consortium. LCOH are used primarily as intermediates, as a precursor to alcohol-based surfactants and as alcohol per se in a wide variety of consumer product applications. Global production volume is approximately 1.58 million metric tonnes. The OECD HPV assessment covers linear to slightly branched LCOH ranging from 6 to 22 alkyl carbons (C). LCOH biodegrade exceptionally rapidly in the environment (half-lives on the order of minutes); however, due to continuous use and distribution to wastewater treatment systems, partitioning properties, biodegradation of alcohol-based surfactants, and natural alcohol sources, LCOH are universally detected in wastewater effluents. An environmental risk assessment of LCOH is presented here by focusing on the most prevalent and toxic members of the linear alcohols, specifically, from C(12-15). The assessment includes environmental monitoring data for these chain lengths in final effluents of representative wastewater treatment plants and covers all uses of alcohol (i.e., the use of alcohol as a substance and as an intermediate for the manufacturing of alcohol-based surfactants). The 90th percentile effluent discharge concentration of 1.979microg/L (C(12)-C(15)) was determined for wastewater treatment plants in 7 countries. Chronic aquatic toxicity studies with Daphnia magna demonstrated that between C(13) and C(15) LCOH solubility became a factor and that the structure-activity relationship was characterized by a toxicity maximum between C(13) and C(14). Above C(14) the LCOH was less toxic and become un-testable due to insolubility. Risk quotients based on a toxic units (TU) approach were determined for various scenarios of exposure and effects extrapolation. The global average TU ranged from 0.048 to 0.467 depending on the scenario employed suggesting a low risk to the environment. The fact that environmental exposure calculations include large fractions of naturally derived alcohol from animal, plant, and microbially mediated biotransformations further supports a conclusion of low risk.

A comparison of dopaminergic cells from the human NTera2/D1 cell line transplanted into the hemiparkinsonian rat.

Human NT cells derived from the NTera2/D1 cell line express a dopaminergic phenotype making them an attractive vehicle to supply dopamine to the depleted striatum of the Parkinsonian patient. In vitro, hNT neurons express tyrosine hydroxylase (TH), depending on the length of time they are exposed to retinoic acid. This study compared two populations of hNT neurons that exhibit a high yield of TH+ cells, MI-hNT and DA-hNT. The MI-hNT and DA-hNT neurons were intrastriatally transplanted into the 6-OHDA hemiparkinsonian rat. Amelioration in rotational behavior was measured and immunohistochemistry was performed to identify surviving hNT and TH+ hNT neurons. Results indicated that both MI-hNT and DA-hNT neurons can survive in the striatum, however, neither maintained their dopaminergic phenotype in vivo. Other strategies used in conjunction with hNT cell replacement are likely needed to enhance and maintain the dopamine expression in the grafted cells.

Alternate approach to understanding the molecular mechanisms of stroke-induced injury.

Research in the area of stroke has not yielded any new treatments, besides tissue plasminogen activator. New findings are suggesting that the therapeutic window of providing neuroprotection is wider than once thought. Moreover, the role of the peripheral immune system in abetting neurodegeneration is being elucidated, but it appears this reaction occurs 2-3 days after the stroke. This mini-review examines this new evidence about the molecular mechanisms leading to stroke-induced neuronal death, which suggests new therapeutic approaches to its treatment.

Influence of retinoic acid and lithium on proliferation and dopaminergic potential of human NT2 cells.

Our laboratory is working with the human NTera2/D1 (NT2) cell line, which has properties similar to those of progenitor cells in the central nervous system (CNS). These neural-like precursor cells can differentiate into all three major lineages, neurons, astrocytes, and oligodendrocytes. The pure neuronal population, hNT neurons, possess characteristics of dopamine (DA) cells. First, we analyzed whether the retinoic acid (RA)-treated hNT neurons and the NT2 precursor cells expressed two transcription factors required for development of the midbrain DA neurons. We report that NT2 cells endogenously expressed Engrailed-1 and Ptx3, whereas RA-treated hNT neurons did not express Engrailed-1 or Ptx3. Next we examined the influence of lithium treatment on Engrailed-1 and Ptx3 as well as another critical transcription factor, Nurr1. Previous research has shown that lithium can mimic the Wnt pathway, which is important for the induction of these transcription factors. Finally, we investigated the effect of lithium treatment on the viability and proliferation of NT2 cells, because lithium has been shown to stimulate neurogenesis in adult neural precursors. Lithium treatment increased the viability and proliferation of NT2 cells. The expression of transcription factors essential for the induction and maintenance of the DA phenotype was not increased in NT2 after lithium treatment. We conclude that the NT2 cell line is an excellent in vitro model system for studying the influence of pharmalogical agents on proliferation, differentiation, and apoptosis of a human neural progenitor cell line.

The role of connexins in the differentiation of NT2 cells in Sertoli-NT2 cell tissue constructs grown in the rotating wall bioreactor.

Neural transplantation is developing as a successful treatment for neurodegenerative diseases such as Parkinson's disease. The human Ntera-2/D1 (NT2) cell line is an attractive alternative to the use of human fetal neurons as a cell source for transplantation. We have explored combining NT2 cells, as a neuronal source, and Sertoli cells, which may act as a graft facilitator to enhance neuronal survival and differentiation, and ameliorate the host immune response, into a tissue construct for use in cell replacement therapy for neurodegenerative disease. This Sertoli-NT2-aggregated cell (SNAC) tissue construct is formed in the high aspect ratio vessel (HARV) bioreactor. NT2 cells differentiate to dopaminergic NT2N neurons within the SNAC tissue construct without retinoic acid. We report here that the gap junction protein connexin 43 is decreased among differentiated NT2N neurons. Inhibition of connexin 43 with 18beta glycyrrhetinic acid and carbenoxolone, a glycyrrhetinic acid derivative, during formation of the SNAC tissue constructs disrupts the differentiation of NT2 cells. Therefore, connexin 43 is important in the differentiation of NT2 cells in the SNAC tissue construct.

Survival of rat or mouse ventral mesencephalon neurons after cotransplantation with rat sertoli cells in the mouse striatum.

Transplanting cells across species (xenotransplantation) for the treatment of Parkinson's disease has been considered an option to alleviate ethical concerns and shortage of tissues. However, using this approach leads to decreased cell survival; the xenografted cells are often rejected. Sertoli cells (SCs) are testis-derived cells that provide immunological protection to developing germ cells and can enhance survival of both allografted and xenografted cells. It is not clear whether these cells will maintain their immunosuppressive support of cografted cells if they are transplanted across species. In this study, we investigated the immune modulatory capacity of SCs and the feasibility of xenografting these cells alone or with allografted and xenografted neural tissue. Transplanting xenografts of rat SCs into the mouse striatum with either rat or mouse ventral mesencephalon prevented astrocytic infiltration of the graft site, although all transplants showed activated microglia within the core of the graft. Surviving tyrosine hydroxylase-positive neurons were observed in all conditions, but the size of the grafts was small at best. SCs were found at 1 and 2 weeks posttransplant. However, few SCs were found at 2 months posttransplant. Further investigation is under way to characterize the immune capabilities of SCs in a xenogeneic environment.

Behavioral alterations in Lewis rats following two-day continuous 3-nitropropionic acid administration.

The mitochondrial toxin, 3-nitropropionic acid (3-NP), produces motor dysfunction and striatal atrophy in rats. However, rat strain and method of administration may contribute to variability in the deficits caused by 3-NP toxicity. To evaluate this, changes in nocturnal spontaneous locomotor activity from chronic administration of 3-NP using an osmotic mini pump, were examined in the Lewis rats. Lewis rats were treated with 3-NP or saline for 2 days and behavior was tested daily for a 15 day period. Animals receiving 3-NP displayed significantly less spontaneous activity than animals in the saline group. 3-NP treated animals also weighed significantly less when compared to saline treated animals. These results demonstrate that even though there were no significant alterations in overt anatomical pathology, even short-term exposure to 3-NP produced significant effects. This short-term administration may present a potential paradigm for examination of sub-threshold neurotoxicity.

Do hematopoietic cells exposed to a neurogenic environment mimic properties of endogenous neural precursors?

Hematopoietic progenitors are cells, which under challenging experimental conditions can develop unusual phenotypic properties, rather distant from their original mesodermal origin. As previously reported, cells derived from human umbilical cord blood (HUCB) or human bone marrow (BM) under certain in vivo or in vitro conditions can manifest neural features that resemble features of neural-derived cells, immunocytochemically and in some instances also morphologically. The present study explored how hematopoietic-derived cells would respond to neurogenic signals from the subventricular zone (SVZ) of adult and aged (6 and 16 months old) rats. The mononuclear fraction of HUCB cells was transplanted into the SVZ of immunosuppressed (single cyclosporin or three-drug treatment) animals. The triple-suppression paradigm allowed us to protect transplanted human cells within the brain and to explore further their phenotypic and migratory properties. One week after implantation, many surviving HUCB cells were located within the SVZ and the vertical limb of the rostral migratory stream (RMS). The migration of HUCB cells was restricted exclusively to the pathway leading to the olfactory bulb. In younger animals, grafted cells navigated almost halfway through the vertical limb, whereas, in the older animals, the migration was less pronounced. The overall cell survival was greater in younger animals than in older ones. Immunocytochemistry for surface CD antigen expression showed that many HUCB cells, either cultured or within the brain parenchyma, retained their hematopoietic identity. A few cells, identified by using human-specific antibodies (anti-human nuclei, or mitochondria) expressed nestin and doublecortin, markers of endogenous neural progenitors. Therefore, it is believed that the environment of the neurogenic SVZ, even in aged animals, was able to support survival, "neuralization," and migratory features of HUCB-derived cells.

Green fluorescent protein bone marrow cells express hematopoietic and neural antigens in culture and migrate within the neonatal rat brain.

Finding a reliable source of alternative neural stem cells for treatment of various diseases and injuries affecting the central nervous system is a challenge. Numerous studies have shown that hematopoietic and nonhematopoietic progenitors derived from bone marrow (BM) under specific conditions are able to differentiate into cells of all three germ layers. Recently, it was reported that cultured, unfractionated (whole) adult BM cells form nestin-positive spheres that can later initiate neural differentiation (Kabos et al., 2002). The identity of the subpopulation of BM cells that contributes to neural differentiation remains unknown. We therefore analyzed the hematopoietic and neural features of cultured, unfractionated BM cells derived from a transgenic mouse that expresses green fluorescent protein (GFP) in all tissues. We also transplanted the BM cells into the subventricular zone (SVZ), a region known to support postnatal neurogenesis. After injection of BM cells into the neurogenic SVZ in neonatal rats, we found surviving GFP+ BM cells close to the injection site and in various brain regions, including corpus callosum and subcortical white matter. Many of the grafted cells were detected within the rostral migratory stream (RMS), moving toward the olfactory bulb (OB), and some cells reached the subependymal zone of the OB. Our in vitro experiments revealed that murine GFP+ BM cells retained their proliferation and differentiation potential and predominantly preserved their hematopoietic identity (CD45, CD90, CD133), although a few expressed neural antigens (nestin, glial fibrillary acdiic protein, TuJ1).

Formation and structure of transplantable tissue constructs generated in simulated microgravity from Sertoli cells and neuron precursors.

Cell transplantation therapy for Parkinson's disease (PD) has received much attention as a potential treatment protocol for this neurodegenerative condition. Although there have been promising successes with this approach, it remains problematic, especially regarding the inability to provide immediate trophic support to the newly grafted cells and the inability to prevent acute and/or long-term graft rejection by the host. To address these issues of cell graftability, we have created a novel tissue construct from isolated rat Sertoli cells (SC) and the NTerra-2 immortalized human neuron precursor cell line (NT2) utilizing NASA-developed simulated microgravity technology. The two cell types were cocultured at a 1:4 (SC/NT2) ratio in the High Aspect Rotating Vessel (HARV) biochamber for 3 days, after which a disc-shaped aggregate (1-4 mm diameter) was formed. Sertoli neuron aggregated cells (SNAC) were collected by gravity sedimentation and processed either for light and electron microscopy or for fluorescent immunocytochemistry. Intra-SNAC clusters of SC and NT2 cells were identified by anti-human mitochondrial protein (huMT--specific for NT2 cells) and cholera toxin subunit B (CTb--specific for SC). There was little evidence of cell death throughout the aggregate and the absence of central necrosis, as might be expected in such a large aggregate in vitro. Ultrastructurally, SC did not express junctional modifications with NT2 cells nor with adjacent SC as is typical of SC in vivo and, in some protocols, in vitro. NT2 cells, however, showed distinct intercellular junction-like densities with adjacent NT2 cells, often defining canaliculi-like channels between the microvillus borders of the cells. The results show that the use of simulated microgravity coculture provides a culture environment suitable for the formation of a unique and viable Sertoli-NT2 (i.e., SNAC) tissue construct displaying intra-aggregate cellular organization. The structural integration of SC with NT2 cells provides a novel transplantable tissue source, which can be tested to determine if SC will suppress rejection of the grafted NT2 cells and provide for their short- and long-term trophic support in situ in the treatment of experimental PD.

Intravenous versus intrastriatal cord blood administration in a rodent model of stroke.

Human umbilical cord blood (hUCB) is a rich source of hematopoietic stem cells that have been used to reconstitute immune cells and blood lineages. Cells from another hematopoietic source, bone marrow, have been found to differentiate into neural cells and are effective in the treatment of stroke. In this study, we administered hUCB cells intravenously into the femoral vein or directly into the striatum and assessed which route of cell administration produced the greatest behavioral recovery in rats with permanent middle cerebral artery occlusion (MCAO). All animals were immunosuppressed with cyclosporine (CSA). When spontaneous activity was measured using the Digiscan automated system, it was found to be significantly less when hUCB was transplanted 24 hr after stroke compared with nontransplanted, stroked animals (P < 0.01). Furthermore, behavioral recovery was similar with both striatal and femoral hUCB delivery. This is in contrast to the step test, in which significant improvements were found only after femoral delivery of the hUCB cells. In the passive avoidance test, transplanted animals learned the task faster than nontransplanted animals (P < 0.05). Together, these results suggest that hUCB transplantation may be an effective treatment for brain injuries, such as stroke, or neurodegenerative disorders. In addition, intravenous delivery may be more effective than striatal delivery in producing long-term functional benefits to the stroked animal.

Lack of NF-kappaB p50 exacerbates degeneration of hippocampal neurons after chemical exposure and impairs learning.

The roles of activated NF-kappaB subunits in the CNS remain to be discerned. Members of this family of transcription factors are essential to diverse physiological processes and can be activated by pathogens, stress, pharmacological agents, and trauma. We are particularly interested in long-term NF-kappaB activation and its involvement in neuroplastic changes in the brain resulting from acquisition of memory as well as injury. Here, we use lesioning by the limbic-specific neurotoxicant trimethyltin (TMT) as a model in which to examine activation of the NF-kappaB p50 subunit before, during, and after neuronal degeneration. Neurons in wild-type mice that survived TMT-induced injury contained activated p50 and did not label with Fluoro-Jade, a histochemical marker of degenerating neurons. Granule cells of the wild-type dentate gyrus subregion, an area particularly vulnerable to TMT-induced degeneration, contained less activated p50 protein than CA regions. We compared the extent of degeneration in wild-type and p50-null mice and found a fivefold increase in death of hippocampal neurons in mice lacking p50. The hippocampus is key to processes of learning and memory, and NF-kappaB has reported involvement in these processes. The enhanced hippocampal degeneration in p50-null mice prompted us to evaluate their basal learning abilities, and we discovered that difficulties in task acquisition were an additional consequence of p50 ablation. These results indicate that absence of p50 negatively modulates learning ability as well as hippocampal responsiveness to brain injury after a chemical-induced lesion.