Collagenofibrotic Glomerulonephropathy with Fibronectin Deposition in a Dog

Abstract

Abstract. We report herein a case of collagenofibrotic glomerulonephropathy in a 3-year-old Shiba Inu with severe proteinuria. Histologically, renal glomeruli were enlarged with massive deposition of a homogeneous eosinophilic substance within the mesangium and capillary walls. The deposits reacted weakly with periodic acid-Schiff, stained deep blue with Masson's trichrome, and were positive by immunofluorescence for type III collagen and fibronectin. Ultrastructurally, the deposits consisted of fibrils and amorphous material in the mesangial matrix and beneath the glomerular capillary endothelium. The fibrils had transverse bands analogous to those of collagen fibrils. Electron microscopy also revealed focal detachment of podocytes and foot process effacement in glomerular tufts, which suggested that podocyte injury had contributed to the development of proteinuria in this dog. The current case resembles collagenofibrotic glomerulonephropathy (CFGN) in humans in histopathologic, immunofluorescence, and electron microscopic findings. This is the first report of CFGN in a nonhuman species with glomerular deposition of fibronectin and type III collagen.

Pathological Characterization of Collagenofibrotic Glomerulonephropathy in a Young Dog

“…The clinical, histopathological, immunohistochemical and electron microscopic findings of the glomerular lesions in the present case were consistent with those of CFGN in both humans [2,6] and animals [1,5,9,11,19]. On light microscopy, adhesion of glomerular tufts to the Bowman's capsules and cellular crescent formation indicated severe injury of the glomerular basement membrane (GBM) and podocytes, as seen in the Shiba Inu dog case [9].…”

“…On light microscopy, adhesion of glomerular tufts to the Bowman's capsules and cellular crescent formation indicated severe injury of the glomerular basement membrane (GBM) and podocytes, as seen in the Shiba Inu dog case [9]. Focal dep- osition of IgG and IgM may be non-specific and non-indicative of immunomediated processes in these glomerular lesions.…”

“…In animals, glomerulonephropathy similar to CFGN has been reported in dogs [9,10], a cat [11], pigs [18,19] and cynomolgus monkeys [1,5]. There have been two reports of canine CFGN.…”

“…There have been two reports of canine CFGN. The first detailed CFGN-like glomerulosclerosis in three Newfoundland dog littermates which were not examined immunohistochemically [10] and the other described CFGN in a 3-year-old Shiba Inu [9]. A genetic disorder is indicated in the former cases, but the cause and pathogenesis of the latter case is unknown.…”

Glomerular Collagen V Codeposition and Hepatic Perisinusoidal Collagen III Accumulation in Canine Collagen Type III Glomerulopathy

“…21 The clinical features in dogs are similar to those of affected children. 7 With one exception, 9 all described canine cases 10,11,21,22 developed clinical signs of chronic renal failure within a year of birth.…”