Estudi de la patogènia de l'encefalopatia espongiforme bovina i de la tremolor ovina en casos de camp

Consultable des del TDXTítol obtingut de la portada digitalitzadaEn el marc del programa de vigilància i control de les EET a Catalunya es van obtenir encèfals de casos de EEB. En primer lloc aquestes mostres van ser caracteritzades. Amb l'estudi de la distribució encefàlica de la proteïna prió resistent (PrPres) mitjançant western blotting (WB) i un assaig d'immunoabsorció amb quimioluminiscència en microplaca (LIA) es va obtenir la corba de distribució encefàlica de la PrPres (BPDC) juntament amb els perfils lesional i immunohistoquímic dels encèfals. Aquesta ens va proporcionar informació sobre l'estadi de la malaltia en cada cas. Els casos els varem classificar com a casos precoços donada l'absència de detecció de signes clínics i el poc abast de les lesions observades. L'estudi en profunditat dels dipòsits de PrPres va aportar-nos informació interessant sobre la implicació de la població glial en la propagació de la PrPres. Continuant amb la caracterització dels casos es va elaborar el perfil molecular de la PrPres de cada cas que s'havia diagnosticat a Catalunya. Això es va fer mitjançant la determinació densitomètrica de la proporció de les tres glicoformes, del pes molecular de la proteïna, un cop deglicosilada, i, finalment valorant la afinitat diferencial a dos anticossos monoclonals, el P4 i el 6H4. Tots els casos avaluats corresponien a casos d'EET clàssics la qual cosa en va permetre descartar la presència de casos d'EET atípics en el pool de casos detectats, fins al moment, a Catalunya. Altres mecanismes de la patogènia que es van estudiar en alguns del casos d'EEB mitjançant tècniques d'immunohistoquimica (IHQ) i histoquímica d'afinitat (HQ) van ser: la resposta glial (IHQ per detectar la proteïna acídica fibril·lar glial dels astròcits i HQ amb la lectina de Griffonia simplicifolia per detectar micròglia), alteracions de les proteïnes sinàptiques (IHQ per detectar sinaptofisina i SNAP 25), alteració de la matriu extracel·lular (HQ amb aglutinina de Wysteria floribunda), presència de fenòmens d'estrès oxidatiu (IHQ per detectar Metal·lotioneines I+II i Nitrotirosina) i mort cel·lular programada (IHQ per detectar Caspasa 3 activada). L'estudi d'aquests casos era d'especial interès ja que es tractava de casos en fases inicials de la neurodegeneració. Es va estudiar finalment un grup d'ovelles afectades de tremolor ovina, en estadis terminals de la malaltia. També es tractava de casos de camp dels que varem realitzar un perfil lesional i immunohistoquímic (de distribució de la PrPres). Un cop caracteritzats varem estudiar les poblacions GABAèrgiques mitjançant IHQ per detectar les proteïnes lligadores de calci, Parvalbúmina i Calbindina, marcadors d'aquesta subpoblació neuronal. Es va observar una important reducció del marcatge de parvalbúmina, afectant sobretot a les prolongacions neuronals. Tot i Aixa no varem detectar cap alteracó de la matriu extracel·lular (HQ amb aglutinina de Wysteria floribunda). Aquesta alteració era concomitant amb un nivell lleu d'espongiosi i un dipòsit evident de PrPres. Aquesta troballa permetia explicar, de forma parcial, alguns dels signes associats a la malaltia com ara els tremolors o la hiperexcitabilitat.The brains of BSE field cases in cattle were collected after diagnosis within the active surveillance programme in Catalonia. First of all a characterisation of the samples was carried out. By studying the brain distribution of the resistant prion protein (PrPres) deposition with western blotting and a luminescence immunosorvent assay a brain PrPres distribution curve (BPDC) was obtained along with lesion and immunohistochemical brain profiles. These yielded information regarding the stage of the disease of the cases which were classified as early cases due to the lack of reported clinical signs and the small extent of the lesion. The in-depth study of PrPres deposition patterns disclosed interesting information on the involvement of glial population in the spread of PrPres. To further characterise the cases a molecular profile of the deposited PrPres in all TSE cases diagnosed in Catalonia was also obtained. A densitometric determination of the glycosilation pattern and of the molecular weight of the deglycosilated PrPres and the differential affinity to 6H4 and P4 monoclonal antibodies were the tools employed. All cases studied fitted into the classical TSE descriptions, thus allowing us to discard the presence of atypical TSE strains among the pool of cases detected through the active surveillance programme. Other pathogenetic mechanisms were then investigated in some of the BSE brains by means of immunohistochemical and histochemical approaches. Glial cell reaction (immunohistochemistry to detect astrocytes against glial fibrillary acidic protein and vimentin and histochemistry for microglia with Griffonia simplicifolia lectin), synaptic protein alterations (IHC against synaptophisin and SNAP25 synaptic proteins), perineuronal nets disruption (HC with Wysteria floribunda agglutinin), presence of oxidative stress phenomena (IHC against Methallotioneins I+II and Nitrotyrosine) and cell death (IHC against cleaved Caspase 3) were the parameters evaluated. Of special interest was the study of these cases since they were in early stages of the neurodegeneration. A group of scrapie, clinically terminal, field cases was also studied. After profiling the lesions and PrPsc distribution, a study of the GABAergic populations was carried out by evaluating the immunolabelling of the calcium binding proteins: parvalbumin and calbindin D28k. An important reduction of the parvalbumin signalling was observed, mainly affecting neuronal prolongations. Despite of that no alteration of the perineuronal nets (studies with HC with Wysteria floribunda agglutinin) was detected. This alteration was concomitant to a mild level of spongyform lesion and an evident deposit of PrPres and could partially be an explanation for the clinical signs observed in the animals such as tremors or hyperexcitability

Un nou estudi demostra que els conills no són resistents a la infecció per prions

Un projecte dut a terme a l'IRTA-CReSA (Barcelona) i el CNB (Madrid), liderat pel CIC bioGUNE (Bilbao), demostra que els conills són susceptibles a les encefalopaties espongiformes, malalties neurodegeneratives causades per prions. La investigació, que ha estat publicada a la revista PLoS Pathogens, ha utilitzat prions reals que es troben en espècies ramaderes. Les conclusions d'aquest estudi són útils per avaluar correctament els riscos associats a l'alimentació d'algunes espècies que, com els conills, es destinen al consum humà.Un proyecto llevado a cabo en el IRTA-CReSA (Barcelona) y el CNB (Madrid), liderado por el CIC bioGUNE (Bilbao), demuestra que los conejos son susceptibles a las encefalopatías espongiformes, enfermedades neurodegenerativas causadas por priones. La investigación, que ha sido publicada en la revista PLoS Pathogens, ha utilizado priones reales que se encuentran especies ganaderas. Las conclusiones de este estudio son útiles para evaluar correctamente los riesgos asociados a la alimentación de algunas especies, como los conejos, que se destinan al consumo humano.A project carried out in IRTA-CReSA (Barcelona) and the CNB (Madrid), led by CIC bioGUNE (Bilbao), shows that rabbits are susceptible to spongiform encephalopathies, neurodegenerative diseases caused by prions. The research, which was published in the journal PLoS Pathogens, used actual prions that are found livestock species. The conclusions of this study are useful to properly assess the risks associated with the feeding of some species, such as rabbits, which are intended for human consumption

Aportació al coneixement de la micoflora del Baix Empordà i rodalies (Catalunya). II. Myxomycetes I

Seguint la sèrie de treballs iniciada pel primer autor, es presenta un recull dels mixomicets conservats en l'herbari del mateix. L'estudi comprèn un llistat de 64 espècies recol·lectades fins avui en aquesta àrea geogràfica, amb comentaris d'aquelles que es consideren més interessants per la seva raresa com sóm Arcyria affinis, A. afroalpina, Cribraria persoonii, Diderma cinereum, Didymium anellus, Didymium serpula, Oligonema schweinitzii i Physarum pezizoideum. D'aquestes espècies, A. afroalpina és nova per a Europa, O. schweinitzii ho és per a Espanya i P. pezizoideum per a Catalunya.Contribution to the fungal flora of Baix Empordà and neighbouring region (Catalonia, NE Spain). II Myxomycetes. I. Following the series of floristic contributions started by the first autor, we present now a study on the myxomycetes preserved in the same author's herbarium. The paper contents a list of the 64 species collected until today in this geographic area, and comments those considered as more interesting: Arcyria affinis, A. afroalpina, Cribraria persoonii, Diderma cinereum, Didymium anellus, Didymium serpula, Oligonema schweinitzii and Physarum pezizoideum. Amongst them, A. afroalpina is an addition to European flora, O. schweinitzii is a new record to the Spanish flora, and P. pezizoideum is new for Catalonia

Aportació al coneixement de la micoflora del Baix Empordà i rodalies (Catalunya). II. Myxomycetes I

Seguint la sèrie de treballs iniciada pel primer autor, es presenta un recull dels mixomicets conservats en l'herbari del mateix. L'estudi comprèn un llistat de 64 espècies recol·lectades fins avui en aquesta àrea geogràfica, amb comentaris d'aquelles que es consideren més interessants per la seva raresa com sóm Arcyria affinis, A. afroalpina, Cribraria persoonii, Diderma cinereum, Didymium anellus, Didymium serpula, Oligonema schweinitzii i Physarum pezizoideum. D'aquestes espècies, A. afroalpina és nova per a Europa, O. schweinitzii ho és per a Espanya i P. pezizoideum per a Catalunya.Contribution to the fungal flora of Baix Empordà and neighbouring region (Catalonia, NE Spain). II Myxomycetes. I. Following the series of floristic contributions started by the first autor, we present now a study on the myxomycetes preserved in the same author's herbarium. The paper contents a list of the 64 species collected until today in this geographic area, and comments those considered as more interesting: Arcyria affinis, A. afroalpina, Cribraria persoonii, Diderma cinereum, Didymium anellus, Didymium serpula, Oligonema schweinitzii and Physarum pezizoideum. Amongst them, A. afroalpina is an addition to European flora, O. schweinitzii is a new record to the Spanish flora, and P. pezizoideum is new for Catalonia

Searching for animal models and potential target species for emerging pathogens : Experience gained from Middle East respiratory syndrome (MERS) coronavirus

Emerging and re-emerging pathogens represent a substantial threat to public health, as demonstrated with numerous outbreaks over the past years, including the 2013-2016 outbreak of Ebola virus in western Africa. Coronaviruses are also a threat for humans, as evidenced in 2002/2003 with infection by the severe acute respiratory syndrome coronavirus (SARS-CoV), which caused more than 8000 human infections with 10% fatality rate in 37 countries. Ten years later, a novel human coronavirus (Middle East respiratory syndrome coronavirus, MERS-CoV), associated with severe pneumonia, arose in the Kingdom of Saudi Arabia. Until December 2016, MERS has accounted for more than 1800 cases and 35% fatality rate. Finding an animal model of disease is key to develop vaccines or antivirals against such emerging pathogens and to understand its pathogenesis. Knowledge of the potential role of domestic livestock and other animal species in the transmission of pathogens is of importance to understand the epidemiology of the disease. Little is known about MERS-CoV animal host range. In this paper, experimental data on potential hosts for MERS-CoV is reviewed. Advantages and limitations of different animal models are evaluated in relation to viral pathogenesis and transmission studies. Finally, the relevance of potential new target species is discussed

A case of uterine inclusion cysts in a sow

Serosal inclusion cysts are thin walled-structures located on the peritoneal surface of the uterus, frequently observed as multiple cystic structures in aggregates or grape-like clusters containing a clear, non-viscous fluid. In human and veterinary medicine, they are thought to be developed under hormonal effects, or after manipulation or inflammation of the reproductive tract. However, they have not yet been described in swine. A uterus of a 3-year-old crossbreed sow was condemned at slaughter due to the presence of multiples cystic cavities attached to the serosal surface. Microscopically, multiple cystic dilations emerging from the serosa were lined by a simple and flattened epithelium (cytokeratine positive and vimentin negative on immunohistochemistry) supported by a subepithelial layer of collagen. Grossly and histologically, they were diagnosed as serosal inclusion cysts. To the authors' knowledge, this report represents the first description of serosal inclusion cysts in sows. These lesions should be taken into consideration within the differential diagnostic list of cystic peritoneal lesions such as cystic neoplasms, congenital cysts, and parasitic diseases

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

Generalized tuberculosis due to Mycobacterium caprae in a red fox phylogenetically related to livestock breakdowns

Ajuts: Generalitat de Catalunya. Departament d'Acció Climàtica, Alimentació i Agenda Rural EFA357/INNOTUBTuberculosis (TB) due to Mycobacterium caprae is endemic in goat herds and free-ranging wild boars in Spain, causing infections in other livestock or wild animals to a lesser extent. TB infection in foxes is infrequently reported and they are usually considered spillover hosts of TB

Bovine Spongiform Encephalopathy Induces Misfolding of Alleged Prion-Resistant Species Cellular Prion Protein without Altering Its Pathobiological Features

Bovine spongiform encephalopathy (BSE) prions were responsible for an unforeseen epizootic in cattle which had a vast social, economic, and public health impact. This was primarily because BSE prions were found to be transmissible to humans. Other species were also susceptible to BSE either by natural infection (e.g., felids, caprids) or in experimental settings (e.g., sheep, mice). However, certain species closely related to humans, such as canids and leporids, were apparently resistant to BSE. In vitro prion amplification techniques (saPMCA) were used to successfully misfold the cellular prion protein (PrPc) of these allegedly resistant species into a BSE-type prion protein. The biochemical and biological properties of the new prions generated in vitro after seeding rabbit and dog brain homogenates with classical BSE were studied. Pathobiological features of the resultant prion strains were determined after their inoculation into transgenic mice expressing bovine andhumanPrPC. Strain characteristics of the in vitro-adapted rabbit and dog BSE agent remained invariable with respect to the original cattle BSE prion, suggesting that the naturally low susceptibility of rabbits and dogs to prion infections should not alter their zoonotic potential if these animals became infected with BSE. This study provides a sound basis for risk assessment regarding prion diseases in purportedly resistant species

Experimental transmission to a calf of an isolate of Spanish classical scrapie

Multiple theories exist regarding the origin of bovine spongiform encephalopathy (BSE). An early and prominent theory proposed that BSE was the result of the adaptation of sheep scrapie to cattle. The reports to date indicate that the distribution of the pathological prion protein (PrPSc) in experimental bovine scrapie is largely restricted to the central nervous system (CNS). Here, we describe pathological findings in a calf intracerebrally inoculated with a Spanish classical scrapie isolate. While clinical disease was observed 30 months after inoculation and PrPSc was detected in the CNS, the corresponding phenotype differed from that of BSE. Immunohistochemistry and PMCA also revealed the presence of PrPSc in the peripheral nerves, lymphoid tissues, skeletal muscle and gastrointestinal tract, suggesting centrifugal spread of the scrapie agent from the brain. To the best of our knowledge, this is the first report describing the detection of PrPSc in tissues other than the CNS after experimental transmission of scrapie to cattle