Central Nervous System Degeneration Research Articles

What we know: the inflammatory basis of hepatic encephalopathy.

Central Nervous System (CNS) degeneration appearing in patients with cirrhosis is responsible for cognitive and persistent motor impairments that lead to an important impact on life quality. Brain injury affects certain areas of the CNS that might affect two types of cells: neurons and astrocytes. The process leading to brain injury could be induced by portosystemic shunting accompanied by hyperammonemia and by the activation of peripheral inflammation, manifested as episodic encephalopathy. Hyperammonemia combined with a decrease on the BCA/AAA ratio induces alterations of energetic metabolism and the formation of free radicals in the CNS. This process would be stimulated by the activation of peripheral inflammatory mediators that could act on receptors of the blood brain barrier such as TLR4, activating inflammatory responses in the CNS. As a result, a persistent activation of microglia and an irreversible neuronal and astrocytic injury would be induced. A new knowledge of the mechanisms leading to brain injury in cirrhosis would develop protective strategies to correct changes of nitrogen metabolism and inflammation.

Relapsing peripheral facial palsy: An unusual early sign of Friedreich ataxia

A 4-year-old child presented with peripheral left facial palsy. Neurological examination was normal except for deep tendon areflexia in the lower limbs. Serologic evaluation and cerebral magnetic resonance imaging to rule out post-infectious causes were normal. Electroneurography (ENG) showed absent sensory action potentials. After 15 days, the patient experienced a relapse of peripheral left facial palsy; ENG was unchanged, and somatosensory evoked potentials showed posterior column involvement. Genetic analysis demonstrated GAA repeat expansion on both alleles (860 and 900 GAA triplets) of the frataxin gene, and the child was diagnosed with Friedreich ataxia. Neurological findings at the last examination, performed at 7 years of age, were unchanged except for mild bilateral pes cavus. Peripheral seventh cranial nerve palsy could be an early and unusual sign of central nervous system degeneration and axonal sensory neuropathy. Its occurrence in this patient provides further evidence that Friedreich ataxia may have a varied clinical presentation at onset. In accordance with other studies, we believe that the size of both GAA expansions affect the age at onset of the disease, despite atypical phenotype.

Effects of Salvia miltiorrhiza on CNS Neuronal Injury and Degeneration: A Plausible Complementary Role of Tanshinones and Depsides.

Salvia miltiorrhiza is a very important herbal drug of traditional Chinese medicine. Bioactive constituents are represented by two main groups of secondary metabolites, the lipophilic diterpenic quinones known as tanshinones and the hydrophilic depsides known as salvianolic acids. S. miltiorrhiza extracts and single constituents have been shown to have positive effects in central nervous system neuronal injury and degeneration in several animal models by various biological mechanisms. Both tanshinones and depsides protect against β-amyloid-induced toxicity, but their mechanisms are complementary due to their different structure, the lipophilic tanshinones and the hydrophilic depsides. A number of anti-inflammatory mechanisms is also reported for both tanshinones and depsides. Common mechanisms are the effects on cytokines, inducible nitric oxide synthase, and glial fibrillary acidic protein. In addition, depsides are inhibitors of nitric oxide and cyclooxygenase-2, while tanshinones inhibit hypoxia-inducible factor-1α and nuclear factor kappa β. Both constituents can also modulate the protection of the central nervous system from oxidative stress with different but complementary mechanisms: tanshinones can enhance the activities of superoxide dismutase and glutathione peroxidase, while depsides can decrease reactive oxygen species.Furthermore, neuronal death underlies the symptoms of many human neurological disorders, including Alzheimer's, Parkinson's, and Huntington's diseases, stroke, and amyotrophic lateral sclerosis. Both classes of constituents can enhance the antiapoptotic B-cell leukemia protein-2 family members and decrease the translocation of cytochrome c, and, in addition, depsides decrease caspase-3 and intracellular Ca(2+). Again, both classes of constituents have an activity on vascular endothelial growth factor but it is opposite, whereas tanshinones are inhibitors of acetylcholinesterase.Besides the extensive studies reporting on the biological mechanisms of depsides and tanshinones, pharmacokinetics studies are still very limited and not conclusive, especially for brain distribution. Further research is warranted to address the mechanisms of the multitarget actions of S. miltiorrhiza constituents and to translate this knowledge into clinical practice.

Acerogenin A from Acer nikoense Maxim Prevents Oxidative Stress-Induced Neuronal Cell Death through Nrf2-Mediated Heme Oxygenase-1 Expression in Mouse Hippocampal HT22 Cell Line.

Oxidative cell damage contributes to neuronal degeneration in many central nervous system (CNS) diseases such as Parkinson’s disease, Alzheimer’s disease, and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a key role in the pathogenesis of neuronal diseases. The stem bark of Acer nikoense Maxim (Aceraceae) is indigenous to Japan; it has been used in folk medicine as a treatment of hepatic disorders and eye diseases. Acerogenin A, a natural compound isolated from Japanese folk medicine A. nikoense, showed neuroprotective effects and reactive oxygen species (ROS) reduction on glutamate-induced neurotoxicity by inducing the expression of HO-1 in mouse hippocampal HT22 cells. Furthermore, acerogenin A caused the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) and the activation of the PI3K/AKT signaling pathways. In this study, we demonstrated that acerogenin A effectively prevents glutamate-induced oxidative damage, and HO-1 induction via PI3K/Akt and Nrf2 pathways appears to play a key role in the protection of HT22 cells. Therefore, this study implies that the Nrf2/HO-1 pathway represents a biological target and that acerogenin A might be a candidate for the prevention of neurodegeneration.

Chronic intermittent ethanol induced axon and myelin degeneration is attenuated by calpain inhibition

Chronic alcohol consumption causes multifaceted damage to the central nervous system (CNS), underlying mechanisms of which are gradually being unraveled. In our previous studies, activation of calpain, a calcium-activated neutral protease has been found to cause detrimental alterations in spinal motor neurons following ethanol (EtOH) exposure in vitro. However, it is not known whether calpain plays a pivotal role in chronic EtOH exposure-induced structural damage to CNS in vivo. To test the possible involvement of calpain in EtOH-associated neurodegenerative mechanisms the present investigation was conducted in a well-established mouse model of alcohol dependence - chronic intermittent EtOH (CIE) exposure and withdrawal. Our studies indicated significant loss of axonal proteins (neurofilament light and heavy, 50–60%), myelin proteins (myelin basic protein, 20–40% proteolipid protein, 25%) and enzyme (2′, 3′-cyclic-nucleotide 3′-phosphodiesterase, 21–55%) following CIE in multiple regions of brain including hippocampus, corpus callosum, cerebellum, and importantly in spinal cord. These CIE-induced deleterious effects escalated after withdrawal in each CNS region tested. Increased expression and activity of calpain along with enhanced ratio of active calpain to calpastatin (sole endogenous inhibitor) was observed after withdrawal compared to EtOH exposure. Pharmacological inhibition of calpain with calpeptin (25μg/kg) prior to each EtOH vapor inhalation significantly attenuated damage to axons and myelin as demonstrated by immuno-profiles of axonal and myelin proteins, and Luxol Fast Blue staining. Calpain inhibition significantly protected the ultrastructural integrity of axons and myelin compared to control as confirmed by electron microscopy. Together, these findings confirm CIE exposure and withdrawal induced structural alterations in axons and myelin, predominantly after withdrawal and corroborate calpain inhibition as a potential protective strategy against EtOH associated CNS degeneration.

P96 – 3019: Hyperactivity, delayed speech, and coarse facies – Comes to mind Sanfilippo syndrome?

Mucopolysaccharidosis-IIIA or Sanfilippo-A syndrome is caused by deficiency of lysosomal a-heparan N-sulfatase that leads to accumulation of heparan-sulphate and degeneration of central nervous system with progressive dementia, hyperactivity, and aggressive behavior. Unlike other mucopolysaccharide disorders, the patients have little somatic features or skeletal changes and a high incidence of false-negative results on the urinary screening tests and so it remains underdiagnosed as a cause of developmental delay both in children and adults. We describe here a boy who presented with developmental delay, hyperactivity and behavioral problems. The attention of pediatricians should be drawn to hyperactivity, delayed language and developmental delay as possible initial presentations of mucopolysaccharidosis in order to avoid needless diagnostic and treatment procedures.

Gene therapy for GM1 gangliosidosis: challenges of translational medicine.

G M1 gangliosidosis is an autosomal recessive lysosomal storage disorder with an estimated incidence of between 1 in 100,000 and 1 in 200,000 (1). Clinical features are predominantly those of a neurodegenerative disorder due to G M1 ganglioside deposition in the central nervous system (CNS). Other clinical features include hepatosplenomegaly, coarse facial features and skeletal dysostosis. The underlying biochemical abnormality is a deficiency of β-galactosidase whose level of activity is inversely proportional to disease severity. While the disease is relatively heterogeneous three clinical subtypes are recognised. In the severe infantile form enzyme activity may be 0.07-1.3% of normal and clinical signs emerge between birth and 6 months of age. The clinical signs are a combination of a neurolipidosis (i.e., neurodegeneration and macular cherry-red spots) and a mucopolysaccharidosis (i.e., organomegaly, dysostosis and coarse facial features). The infantile form is characterised by a rapidly progressive course with severe CNS degeneration and death by 1-2 years of age commonly due to aspiration pneumonia or cardiomyopathy. The juvenile form is associated with enzyme activity in the order of 0.3-4.8% of normal and presents between 7 months and 3 years of age. It is characterised by psychomotor retardation with the other features of the infantile form being present in variable degrees. Disease progression is slower than the infantile form and death typically occurs before the second decade of life. The adult form occurs in those with an enzyme activity in the region of 5-10% of normal and is characterised by normal early neurological development with symptom onset between 3-30 years of age. Characteristic features are of a slowly progressive dementia, parkinsonism and dystonia. There is marked phenotypic variability in the adult form and the age of death varies widely. The diagnosis can be made by measuring β-galactosidase activity in peripheral blood leucocytes or by β-galactosidase gene ( GLB1 ) molecular testing. Over 100 mutations have been reported in GLB1 (1) and there is no clear correlation between genotype and phenotype.

Defining the Tetramodular Dimer Structure of Laforin in Glycogen Metabolism and Lafora Disease

Glycogen is the major form of carbohydrate storage in mammals and a dynamic participant in brain energetics. Slight aberrations in glycogen metabolism induce neuronal apoptosis; thus glycogen must be highly regulated. Lafora disease (LD) is a recessive neurodegenerative disorder that manifests as a single seizure during adolescence followed by progressive central nervous system degeneration and death within ten years. Mutations in the glycogen phosphatase laforin lead to the accumulation of neurotoxic, hyperphosphorylated glycogen known as Lafora bodies, which cause LD. Our lab recently determined the crystal structure of dimeric laforin. Using a variety of biochemical and biophysical methods including size exclusion chromatography, analytical ultracentrifugation, and small angle X‐ray scattering we have demonstrated that laforin exists as a dimer in solution. We have probed the effects of mechanistic and LD‐associated mutations using a yeast two‐hybrid system and various in vitro techniques, and we have demonstrated that laforin dimerization plays a unique and critical role in glycogen binding and dephosphorylation. This work begins to define the mutation‐specific mechanisms of LD and sheds new light on the regulation of glycogen metabolism.

Effect of apoptosis in neural stem cells treated with sevoflurane.

BackgroundAt present, sevoflurane inhalation anesthesia used on infants is well-known. But long-time exposure to inhalation anesthetic could cause neurologic disorder, especially nerve degeneration in infant and developing brain. The central nervous system degeneration of infants could affect the memory and cognitive function. γ-Aminobutyric acid (GABA) is a known inhibitory neurotransmitter in central nervous system. Inhalation anesthetic sevoflurane may activate GABAA receptor to inhibit central nervous system, leading to apoptosis of neural degeneration, cognitive dysfunction in the critical period of brain development.MethodsNeural stem cells were derived from Wistar embryos, cultured in vitro. Third generation of neural stem cells were randomly divided into four groups according to cultured suspension: Sevoflurane group (Group S), GABAA receptor antagonists, Bicuculline group (Group B), Sevoflurane + GABAA receptor antagonists, Bicuculline group (Group S + B), dimethyl sulphoxide (DMSO) group (Group D). Group B and Group D did not receive sevoflurane preconditioning. Group S and Group S + B were pretreated with 1 minimum alveolar concentration (MAC) sevoflurane for 0 h, 3 h, 6 h, and 12 h. Group S + B and Group B were pretreated with bicuculline (10 uM). Group D was treated with DMSO (10 uL/mL). After treatments above, all groups were cultured for 48 h. Then we measured the cells viability by Cell Counting Kit (CCK-8) assay, cytotoxicity by Lactate Dehydrogenase (LDH) assay, apoptosis ratio with Annexin V/propidium iodide (PI) staining by flow cytometry, and the expression of GABAAR, anti-apoptotic protein Bcl-2, pro-apoptotic protein Bax and Caspase-3 by western blotting.ResultsAfter exposing to sevoflurane for 0 h, 3 h, 6 h, and 12 h with 1MAC, we found that cell viability obviously decreased and cytotoxicity increased in time-dependent way. And Annexin V/PI staining indicated increased apoptosis ratio by flow cytometry. The protein level of GABAA receptor, pro-apoptotic protein Bax and apoptosis protein Caspase-3 increased; while anti-apoptotic protein Bcl-2 decreased. And bicuculline could reverse all detrimental results caused by sevoflurane.ConclusionSevoflurane can inhibit the central nervous system by activating GABAA, resulting in apoptosis of neural stem cells, thus leading to the NSCs degeneration.

Role of MicroRNAs in Development of Immune Cells and Nervous System and their Relation to Multiple Sclerosis

Introduction: MicroRNAs (miRNAs) are small and non-coding ribonucleic acids that play critical roles in regulation of host genome expression at post-transcriptional level. An individual miRNA is able to down-regulate multiple targeted mRNA transcripts. Therefore, minor changes in a miRNA expression may lead to significant alterations in the expression of different genes. During last two decades, miRNAs have emerged as key regulators of immune cell lineage differentiation, maturation, maintenance of immune homeostasis, and normal function. Multiples sclerosis (MS) is a chronic inflammatory disease that is characterized by infiltration of lymphocytes into the central nervous system (CNS), demyelination and axonal degeneration. Although causes of MS are still unknown, it is widely accepted that novel drug targets need to focus on both decreasing inflammation and promoting CNS repair. Recent researches about MS disease have shown that miRNAs are dysregulated in the immune system and CNS, which shows their role in the MS pathogenesis. Conclusion: Identification of specific expression patterns of miRNA in autoimmune diseases and a further comprehensive understanding of their role in the pathogenesis of different diseases offers promise of not only novel molecular diagnostic markers but also new gene therapy strategies for treating inflammatory autoimmune diseases. In this study, we review the latest findings about miRNA biogenesis and signatures in the CNS and immune cells of MS patients.

Early microlesion of viral encephalitis confirmed by galectin-3 expression after a virus inoculation

Galectin-3 is a β-galactosidase-binding lectin which is important in cell proliferation and apoptotic regulation. Encephalomyocarditis virus (EMCV), which includes the Enterovirus genus, can cause not only acute myocarditis but also neuronal degeneration of central nervous system in various animals including mice. The pathophysiological role of galectin-3 in central nervous system following acute viral infection is not fully understood. The goal of this study is to determine the localization and time-course of galectin-3 expression after acute viral inoculation with EMCV. Galectin-3 is up-regulated in degenerated lesions of brain area including cerebellum, hippocampus, thalamus and cerebral hemisphere, 96h after EMCV inoculation. At the same time, Iba-1 positive microglia was morphologically activated within and around the focus of infection. Interestingly, in cerebellum, the microlesions containing a few galectin-3 cells were detected in the immediate-early phase of infection, as early as 48h after EMCV inoculation. Thus, our results indicate that galectin-3 expression may be a key mediator between viral infection and neuronal degeneration in central nervous system including cerebellum. Furthermore, detection of galectin-3 might be an early diagnostic method for neuronal degeneration after virus infection.

CFLIP is critical for oligodendrocyte protection from inflammation.

Neuroinflammation associated with degenerative central nervous system disease and injury frequently results in oligodendrocyte death. While promoting oligodendrocyte viability is a major therapeutic goal, little is known about protective signaling strategies. We report that in highly purified rat oligodendrocytes, interferon gamma (IFNγ) activates a signaling pathway that protects these cells from tumor necrosis factor alpha (TNFα)-induced cytotoxicity. IFNγ protection requires Jak (Janus kinase) activation, components of the integrated stress response and NF-κB activation. Although NF-κB activation also occurred transiently in the absence of IFNγ and presence of TNFα, this activation was not sufficient to prevent induction of the TNFα-responsive cell death pathway. Genetic inhibition of NF-κB translocation to the nucleus abrogated IFNγ-mediated protection and did not change the cell death induced by TNFα, suggesting that NF-κB activation via IFNγ induces a different set of responses than activation of NF-κB via TNFα. A promising candidate is the NF-κB target cFLIP (cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein), which is protease-deficient caspase homolog that inhibits caspase-3 activation. We show that IFNγ-mediated protection led to upregulation of cFLIP. Overexpression of cFLIP was sufficient for oligodendrocyte protection from TNFα and short hairpin RNA knockdown of cFLIP-abrogated IFNγ -mediated protection. To determine the relevance of our in vitro finding to the more complex in vivo situation, we determined the impact on oligodendrocyte death of regional cFLIP loss of function in a murine model of neuroinflammation. Our data show that downregulation of cFLIP during inflammation leads to death of oligodendrocytes and decrease of myelin in vivo. Taken together, we show that IFNγ-mediated induction of cFLIP expression provides a new mechanism by which this cytokine can protect oligodendrocytes from TNFα-induced cell death.

The relationship between the degree of cognitive impairment and retinal nerve fiber layer thickness.

The goal of the present study is to investigate the relationship between the degree of cognitive impairment and retinal nerve fiber layer (RNFL) thickness which is measured by the optical coherence tomography (OCT). Thirty-five patients with Alzheimer's disease (AD), 35 patients with mild cognitive impairment (MCI), and 35 healthy volunteers, between the ages of 60-87, who were examined in the neurology outpatient clinic among 2012-2013 were prospectively involved in our study. Mini mental state examination (MMSE) test, montreal cognitive assessment (MOCA), and also neuropsychological test batteries were used for the neurocognitive evaluation. RNFL thickness was measured by the OCT technique and the differences among groups were studied. The relationship between RNFL thickness and MMSE scores with demographic characteristics was investigated. RNFL thickness was significantly lower in AD and MCI groups compared with the control group (p < 0.01). No significant differences of RNFL were found between the MCI and the AD groups (p > 0.05). Significant correlation was found between MMSE scores and the RNFL values (p < 0.05). Significant thinning in RNFL along with age was detected (p < 0.05). In our study, it is thought that retinal nerve fiber degeneration and central nervous system degeneration may be concurrent according to the thinning of RNFL measured by OCT in AD and MCI groups. RNFL measurement may also be useful for early diagnosis and evaluation of the disease progression. Further studies are needed to optimize the utility of this method as an ocular biomarker in AD.

3-acetylpyridine-induced degeneration in the adult ascidian neural complex: Reactive and regenerative changes in glia and blood cells.

Ascidians are interesting neurobiological models because of their evolutionary position as a sister-group of vertebrates and the high regenerative capacity of their central nervous system (CNS). We investigated the degeneration and regeneration of the cerebral ganglion complex of the ascidian Styela plicata following injection of the niacinamide antagonist 3-acetylpyridine (3AP), described as targeting the CNS of several vertebrates. For the analysis and establishment of a new model in ascidians, the ganglion complex was dissected and prepared for transmission electron microscopy (TEM), routine light microscopy (LM), immunohistochemistry and Western blotting, 1 or 10 days after injection of 3AP. The siphon stimulation test (SST) was used to quantify the functional response. One day after the injection of 3AP, CNS degeneration and recruitment of a non-neural cell type to the site of injury was observed by both TEM and LM. Furthermore, weaker immunohistochemical reactions for astrocytic glial fibrillary acidic protein (GFAP) and neuronal βIII-tubulin were observed. In contrast, the expression of caspase-3, a protein involved in the apoptotic pathway, and the glycoprotein CD34, a marker for hematopoietic stem cells, increased. Ten days after the injection of 3AP, the expression of markers tended toward the original condition. The SST revealed attenuation and subsequent recovery of the reflexes from 1 to 10 days after 3AP. Therefore, we have developed a new method to study ascidian neural degeneration and regeneration, and identified the decreased expression of GFAP and recruitment of blood stem cells to the damaged ganglion as reasons for the success of neuroregeneration in ascidians.

Distinct roles of microglia and monocytes in central nervous system inflammation and degeneration

AbstractMonocytes and microglia both originate from myeloid precursor cells and share common characteristics even after differentiation. Recent studies have shown functional differences between these cell types, indicating their unique roles in lesion formation in neurodegenerative diseases. The present review summarizes the functional characteristics of these “similar but different” macrophages in both health and disease.

Establishment of an experimental ferret ocular hypertension model for the analysis of central visual pathway damage.

Glaucoma optic neuropathy (GON) is a condition where pathogenic intraocular pressure (IOP) results in axonal damage following retinal ganglion cell (RGC) death, and further results in secondary damage of the lateral geniculate nucleus (LGN). Therapeutic targets for glaucoma thus focus on both the LGN and RGC. However, the temporal and spatial patterns of degeneration and the mechanism of LGN damage have not been fully elucidated. Suitable and convenient ocular hypertension (OH) animal models with binocular vision comparable to that of monkeys are strongly needed. The ferret is relatively small mammal with binocular vision like humans – here we report on its suitability for investigating LGN. We developed a new method to elevate IOP by injection of cultured conjunctival cells into the anterior chamber to obstruct aqueous outflow. Histologically, cultured conjunctival cells successfully proliferated to occlude the angle, and IOP was elevated for 13 weeks after injection. Macroscopically, the size of the eye gradually expanded. Subsequent enlargement of optic nerve head cupping and atrophic damage of LGN projected from the OH eye were clearly observed by anterograde staining with cholera toxin B. We believe the ferret may be a promising OH model to investigate secondary degeneration of central nervous system including LGN.

Cudarflavone B Provides Neuroprotection against Glutamate-Induced Mouse Hippocampal HT22 Cell Damage through the Nrf2 and PI3K/Akt Signaling Pathways

Oxidative cell damage contributes to neuronal degeneration in many central nervous system (CNS) diseases such as Alzheimer’s disease, Parkinson’s disease, and ischemia. Nrf2 signaling-mediated heme oxygenase (HO)-1 expression acts against oxidants that are thought to play a key role in the pathogenesis of neuronal diseases. Cudraflavone B is a prenylated flavone isolated from C. tricuspidata which has shown anti-proliferative activity, mouse brain monoamine oxidase (MAO) inhibitory effects, apoptotic actions in human gastric carcinoma cells and mouse melanoma cells, and hepatoprotective activity. In this study, cudraflavone B showed neuroprotective effects and reactive oxygen species (ROS) inhibition against glutamate-induced neurotoxicity by inducing the expression of HO-1 in mouse hippocampal HT22 cells. Furthermore, cudraflavone B caused the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) and increased the promoter activity of antioxidant response elements (ARE) in mouse hippocampal HT22 cells. In addition, we found that the Nrf2-midiated HO-1 expression by cudraflavone B is involved in the cell protective response and ROS reductions, and cudraflavone B-induced expression of HO-1 was mediated through the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in HT22 cells. Our results demonstrated the potential application of naturally occurring cudraflavone B as a therapeutic agent from neurodegenerative disease.

Review: Laboratory diagnosis and surveillance of Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a representative human transmissible spongiform encephalopathy associated with central nervous system degeneration. Prions, the causative agents of CJD, are composed of misfolded prion proteins and are able to self-replicate. While CJD is a rare disease affecting only 1-1.5 people per million worldwide annually, it has attracted both scientific and public attention as a threatening disease since an epidemic of variant CJD (vCJD) cases appeared in the mid-1990s. Due to its unconventional transmission and invariable fatality, CJD poses a serious risk to public health. The hundreds of sporadic, genetic, and iatrogenic CJD cases as well as potential zoonotic transmission suggest that CJD is an ongoing concern for the field of medicine. Nevertheless, treatment aimed at clinical prevention and treatment that reverses the course of disease does not exist currently. Active surveillance and effective laboratory diagnosis of CJD are, therefore, critical. In this report, the surveillance systems and laboratory tests used currently to diagnose CJD in different countries are reviewed. The current efforts to improve surveillance and diagnosis for CJD using molecular and biochemical findings are also described.

Enteric GFAP expression and phosphorylation in Parkinson's disease.

Enteric glial cells (EGCs) are in many respects similar to astrocytes of the central nervous system and express similar proteins including glial fibrillary acidic protein (GFAP). Changes in GFAP expression and/or phosphorylation have been reported during brain damage or central nervous system degeneration. As in Parkinson's disease (PD) the enteric neurons accumulate α-synuclein, and thus are showing PD-specific pathological features, we undertook the present survey to study whether the enteric glia in PD become reactive by assessing the expression and phosphorylation levels of GFAP in colonic biopsies. Twenty-four PD, six progressive supranuclear palsy (PSP), six multiple system atrophy (MSA) patients, and 21 age-matched healthy controls were included. The expression levels and the phosphorylation state of GFAP were analyzed in colonic biopsies by western blot. Additional experiments were performed using real-time PCR for a more precise analysis of the GFAP isoforms expressed by EGCs. We showed that GFAPκ was the main isoform expressed in EGCs. As compared to control subjects, patients with PD, but not PSP and MSA, had significant higher GFAP expression levels in their colonic biopsies. The phosphorylation level of GFAP at serine 13 was significantly lower in PD patients compared to control subjects. By contrast, no change in GFAP phosphorylation was observed between PSP, MSA and controls. Our findings provide evidence that enteric glial reaction occurs in PD and further reinforce the role of the enteric nervous system in the initiation and/or the progression of the disease. We showed that GFAP is over-expressed and hypophosphorylated in the enteric glial cells (EGCs) of Parkinson's disease (PD) patients as compared to healthy subjects and patients with atypical parkinsonism (MSA, multiple system atrophy and PSP, progressive supranuclear palsy). Our findings provide evidence that enteric glial reaction occurs in PD but not in PSP and MSA and further reinforce the role of the enteric nervous system in the pathophysiology of PD.

Increased expression of Aquaporin 4 in the rat hippocampus and cortex during trimethyltin-induced neurodegeneration

Trimethyltin chloride (TMT) is a neurotoxicant producing neuronal degeneration and reactive astrogliosis in the mammalian central nervous system, especially the hippocampus. A previous magnetic resonance imaging investigation in TMT-treated rats evidenced dilation of lateral ventricles, also suggesting alterations in blood–brain barrier permeability and brain edema.Aquaporin 4 (AQP4), a glial water channel protein expressed mainly in the nervous system, is considered a specific marker of vascular permeability and thought to play an important role in brain edema (conditions). We studied AQP4 expression in the hippocampus and cerebral cortex of TMT-treated rats in order to explore the molecular mechanisms involved in brain edema occurring in these experimental conditions.Real-time PCR and western blotting data showed significant up-regulation of both AQP4 mRNA and protein levels starting 14days after TMT treatment in the hippocampus and cortex. Parallel immunofluorescence studies indicated intense astrogliosis and AQP4 immunoreactivity diffusely pronounced in the hippocampal and cortex areas starting 14days after TMT intoxication. In order to study the effects of TMT on vascular integrity, double-label immunofluorescence experiments for rat immunoglobulin G (IgG) and rat endothelial cell antigen-1 (RECA-1) or neuronal nuclei (NeuN) (endothelial and neuronal markers respectively) were performed. The results indicated, at 21 and 35days after treatment, the presence of rat IgG in paravasal parenchyma and in some neuronal cells of the hippocampus and cortex. The extravasated IgG staining was temporally correlated with over-expression of neuronal vascular endothelial growth factor (VEGF) and the active phosphorylated form of its neuronal receptor (VEGFR-2P), suggesting that these factors may cooperate in mediating vascular leakage.