Naturally occurring parvovirus-associated feline hypogranular cerebellar hypoplasia-- A comparison to experimentally-induced lesions using immunohistology.
Three cases of feline cerebellar hypoplasia are presented. At the time of examination, the ages of the cats ranged from 2 months to 1 year. Necropsy revealed cerebellar and pons hypoplasia. Polymerase chain reaction for parvoviral deoxyribonucleic acid was positive in cerebellar tissue. Cell-specific immunolabeling was used to characterize the lesions, which were characterized into 2 types. In type 1 lesions, the cortex was nearly agranular, with an extremely thin molecular layer; the Purkinje cells were randomly placed and oriented, and their stunted main dendrite produced a thorn-covered atrophic dendritic tree; the basket cell axons ran randomly and had dysmorphic endings; and myelinated fibers were severely reduced in folia axes. In type 2 lesions, the cortex was hypogranular; the Purkinje cells were linearly organized, but their main dendrite extended too far in the molecular layer before giving up smooth, bent secondary dendrites; many basket cells were located along the cerebellar surface, and their axons ran at right angle to the surface; myelinated fibers were moderately reduced. Defects in climbing fiber synapse translocation and elimination were evident in both types of lesion. This immunohistologic study allowed a comparison between lesions in these spontaneous cerebellar hypoplasia cases with those documented when using silver impregnation studies after perinatal experimental cerebellar damage. Such a comparison is consistent with viral infection that occurs before birth in all 3 cases. Progress in parvovirus biology knowledge suggests that viral NS1 protein cytotoxicity might explain degenerative changes in the Purkinje cells that were present, in addition to the development defect.
Anatomy and Embryology, Faculty of Medicine, Free University of Brussels, Belgium.
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Poncelet
D000818:Animals; D002371:Cat Diseases / Q000473:pathology*; D002415:Cats; D002526:Cerebellar Diseases / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D002531:Cerebellum / Q000473:pathology; D028301:Feline Panleukopenia Virus; D007150:Immunohistochemistry / Q000662:veterinary*; D010322:Parvoviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology