title: Olfactory system involvement in natural scrapie disease.
abstract: The olfactory system (OS) is involved in many infectious and neurodegenerative diseases, both human and animal, and it has recently been investigated in regard to transmissible spongiform encephalopathies. Previous assessments of nasal mucosa infection by prions following intracerebral challenge suggested a potential centrifugal spread along the olfactory nerve fibers of the pathological prion protein (PrP(Sc)). Whether the nasal cavity may be a route for centripetal prion infection to the brain has also been experimentally studied. With the present study, we wanted to determine whether prion deposition in the OS occurs also under field conditions and what type of anatomical localization PrP(Sc) might display there. We report here on detection by different techniques of PrP(Sc) in the nasal mucosa and in the OS-related brain areas of sheep affected by natural scrapie. PrP(Sc) was detected in the perineurium of the olfactory nerve bundles in the medial nasal concha and in nasal-associated lymphoid tissue. Olfactory receptor neurons did not show PrP(Sc) immunostaining. PrP(Sc) deposition was found in the brain areas of olfactory fiber projection, chiefly in the olfactory bulb and the olfactory cortex. The prevalent PrP(Sc) deposition patterns were subependymal, perivascular, and submeningeal. This finding, together with the discovery of an intense PrP(Sc) immunostaining in the meningeal layer of the olfactory nerve perineurium, at the border with the subdural space extension surrounding the nerve rootlets, strongly suggests a probable role of cerebrospinal fluid in conveying prion infectivity to the nasal submucosa.
authors.affiliation: CEA, Italian Reference Laboratory for TSE, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Corona
authors.forename: Chiara
authors.initials: C
authors.lastname: Porcario
authors.forename: Francesca
authors.initials: F
authors.lastname: Martucci
authors.forename: Barbara
authors.initials: B
authors.lastname: Iulini
authors.forename: Barbara
authors.initials: B
authors.lastname: Manea
authors.forename: Marina
authors.initials: M
authors.lastname: Gallo
authors.forename: Claudia
authors.initials: C
authors.lastname: Palmitessa
authors.forename: Cristiana
authors.initials: C
authors.lastname: Maurella
authors.forename: Maria
authors.initials: M
authors.lastname: Mazza
authors.forename: Marzia
authors.initials: M
authors.lastname: Pezzolato
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Acutis
authors.forename: Cristina
authors.initials: C
authors.lastname: Casalone
mesh_terms: D000818:Animals; D009297:Nasal Mucosa / Q000737:chemistry* / Q000473:pathology; D009830:Olfactory Bulb / Q000737:chemistry / Q000473:pathology; D009832:Olfactory Nerve / Q000737:chemistry* / Q000473:pathology; D009833:Olfactory Pathways / Q000737:chemistry* / Q000473:pathology; D018034:Olfactory Receptor Neurons / Q000737:chemistry / Q000473:pathology; D010525:Peripheral Nerves / Q000737:chemistry; D018620:PrPSc Proteins / Q000032:analysis*; D012608:Scrapie / Q000473:pathology*; D012756:Sheep
chemical_list: D018620:PrPSc Proteins