Investiguen el paper de les metal·lotioneïnes en les Encefalopaties Enpongiformes Transmissibles

Les metal·lotioneïnes (MT) formen part dels mecanismes encefàlics de defensa que actuen en cas d'un procés patològic que afecti el sistema nerviós central. Per això, i per les seves propietats antioxidants, investigadors del CReSA i de la UAB han inoculat, per via intracerebral, una soca d'EETs a ratolins transgènics per intentar comprendre millor la relació que existeix entre les MTs i la patogènia de la tremolor ovina

El prió de la tremolor ovina atípica no presenta limfotropisme

Dins el marc del programa de vigilància activa de les encefalopaties espongiformes transmissibles (EETs) a Catalunya, el laboratori Priocat del Centre de Recerca en Sanitat Animal (CReSA) ha evidenciat la inexistència de limfotropisme per part de la proteïna resistent associada a la tremolor ovina atípica. Uns resultats que s'extreuen del següent article, on es presenta de forma concomitant una encefalitis vírica -el que implica la formació de fol·licles limfoides a l'encèfal- i una malaltia priònica. Així, mentre els prions de la variant clàssica s'acumulen al teixit limfàtic, els de la variant atípica no ho fan ni tan sols estant presents al cervell.En el marco del programa de vigilancia activa de las encefalopatías espongiformes transmisibles (EETs) de Catalunya, el laboratorio Priocat del Centro de Investigación en Sanidad Animal (CReSA) ha evidenciado la inexistencia de limfotropismo por parte de la proteína resistente asociada al temblor ovino atípico. Unos resultados que se extraen del siguiente artículo, donde se presenta de forma concomitante una encefalitis vírica -lo que implica la formación de folículos linfoides en el encéfalo- y una enfermedad priónica. Así, mientras los priones de la variante clásica se acumulan en el tejido linfático, los de la variante atípica no lo hacen ni siquiera estando presentes en el cerebro.From the active TSE surveillance programme in Catalonia, the Priocat laboratory of animal health research centre (CReSA) has detected a noticeable lack of lymphotropsim as far as scrapie-associated prion protein deposition is concerned. Results described in the paper, where a viral encephalitis -which implies formation of lymphoid follicles in the brain- is concomitant to a prion disease. In the classical strains the prions show a strong affinity for the lymphoid tissue but not in this case, even when follicles are as close as in the same brain

Investiguen el paper de les metal·lotioneïnes en les Encefalopaties Enpongiformes Transmissibles

Les metal·lotioneïnes (MT) formen part dels mecanismes encefàlics de defensa que actuen en cas d'un procés patològic que afecti el sistema nerviós central. Per això, i per les seves propietats antioxidants, investigadors del CReSA i de la UAB han inoculat, per via intracerebral, una soca d'EETs a ratolins transgènics per intentar comprendre millor la relació que existeix entre les MTs i la patogènia de la tremolor ovina

El prió de la tremolor ovina atípica no presenta limfotropisme

Dins el marc del programa de vigilància activa de les encefalopaties espongiformes transmissibles (EETs) a Catalunya, el laboratori Priocat del Centre de Recerca en Sanitat Animal (CReSA) ha evidenciat la inexistència de limfotropisme per part de la proteïna resistent associada a la tremolor ovina atípica. Uns resultats que s'extreuen del següent article, on es presenta de forma concomitant una encefalitis vírica -el que implica la formació de fol·licles limfoides a l'encèfal- i una malaltia priònica. Així, mentre els prions de la variant clàssica s'acumulen al teixit limfàtic, els de la variant atípica no ho fan ni tan sols estant presents al cervell.En el marco del programa de vigilancia activa de las encefalopatías espongiformes transmisibles (EETs) de Catalunya, el laboratorio Priocat del Centro de Investigación en Sanidad Animal (CReSA) ha evidenciado la inexistencia de limfotropismo por parte de la proteína resistente asociada al temblor ovino atípico. Unos resultados que se extraen del siguiente artículo, donde se presenta de forma concomitante una encefalitis vírica -lo que implica la formación de folículos linfoides en el encéfalo- y una enfermedad priónica. Así, mientras los priones de la variante clásica se acumulan en el tejido linfático, los de la variante atípica no lo hacen ni siquiera estando presentes en el cerebro.From the active TSE surveillance programme in Catalonia, the Priocat laboratory of animal health research centre (CReSA) has detected a noticeable lack of lymphotropsim as far as scrapie-associated prion protein deposition is concerned. Results described in the paper, where a viral encephalitis -which implies formation of lymphoid follicles in the brain- is concomitant to a prion disease. In the classical strains the prions show a strong affinity for the lymphoid tissue but not in this case, even when follicles are as close as in the same brain

Pruritus is a common feature in sheep infected with the BSE agent

Background: The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist. Results: Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16-20 weeks. Conclusion: Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route of inoculation and whether BSE was passed into sheep from cattle or from other sheep, suggesting that the clinical phenotype of BSE is influenced by the TSE strain more than by other factors. The clinical phenotype of BSE in the genotypes and breed studied was indistinguishable from that described for classical scrapie cases

Central nervous system gene expression changes in a transgenic mouse model for bovine spongiform encephalopathy

Gene expression analysis has proven to be a very useful tool to gain knowledge of the factors involved in the pathogenesis of diseases, particularly in the initial or preclinical stages. With the aim of finding new data on the events occurring in the Central Nervous System in animals affected with Bovine Spongiform Encephalopathy, a comprehensive genome wide gene expression study was conducted at different time points of the disease on mice genetically modified to model the bovine species brain in terms of cellular prion protein. An accurate analysis of the information generated by microarray technique was the key point to assess the biological relevance of the data obtained in terms of Transmissible Spongiform Encephalopathy pathogenesis. Validation of the microarray technique was achieved by RT-PCR confirming the RNA change and immunohistochemistry techniques that verified that expression changes were translated into variable levels of protein for selected genes. Our study reveals changes in the expression of genes, some of them not previously associated with prion diseases, at early stages of the disease previous to the detection of the pathological prion protein, that might have a role in neuronal degeneration and several transcriptional changes showing an important imbalance in the Central Nervous System homeostasis in advanced stages of the disease. Genes whose expression is altered at early stages of the disease should be considered as possible therapeutic targets and potential disease markers in preclinical diagnostic tool development. Genes non-previously related to prion diseases should be taken into consideration for further investigations