RESUMO
Collagen type III glomerulopathy, also known as collagenofibrotic glomerulopathy, is a rare renal disease of unknown pathogenesis. The disease occurs in humans and animals and is characterized by massive glomerular accumulations of collagen type III. In the present study, we describe a Drever dog litter affected by an early onset variant of this glomerular disease, where 4 of 9 puppies developed renal failure within 50 days of age. Necropsy specimens of kidney from the 4 affected cases were studied by light microscopy, electron microscopy, and immunohistochemistry, and characteristic lesions compatible with a diagnosis of collagen type III glomerulopathy were found. In addition, 2 cases showed atypical epithelium in the collecting ducts of the medulla, so-called adenomatoid change. Immunohistochemistry of renal specimens from collagen type III glomerulopathy-affected dogs (n = 10) originating from two different dog strains, the Drever dogs and a mixed-breed strain, demonstrated that the deposited glomerular collagen is composed of a mixture of collagen III and collagen V. The distribution of the collagen V corresponded to the localization of collagen III; however, differences in staining intensity showed that collagen type III is the dominating component. Immunohistochemistry for collagen III (n = 9) and a transmission electron microscopic study (n = 1) showed hepatic perisinusoidal collagen type III deposition in affected cases from both dog strains. This is the first report documenting glomerular accumulations of collagen type V and perisinusoidal liver collagen III deposition in canine collagen type III glomerulopathy.
