Glomerulopathy in a cat with cyanotic congenital heart disease

Immune-complex glomerulonephritis in cats: a retrospective study based on clinico-pathological data, histopathology and ultrastructural features

BACKGROUND

Chronic kidney disease (CKD) has typically a non-immune mediated origin in cats and immune-complex glomerulonephritis (ICGN) is scarcely described. Aims of this study were to characterize ICGN by light and electron microscopy and identify associations with clinico-pathological findings. In addition, comparisons between cats with ICGN and non immune-complex glomerulonephritis (non-ICGN) were performed. Renal samples examined between 2010 and 2019 were considered if both light and electron microscopy were performed. Signalment, feline immunodeficiency virus (FIV) and leukemia virus (FeLV) status, serum creatinine concentration, urine protein-to-creatinine (UPC) ratio, systolic blood pressure (SBP) and International Renal Interest Society (IRIS) stage were retrieved and used for comparisons.

RESULTS

Sixty-eight client-owned cats were included. Thirty-seven cats (54.4%) had ICGN and 31 (45.6%) non-ICGN. Eighteen (48.6%) with ICGN had membranous glomerulonephropathy (MGN), 14 (37.8%) membranoproliferative glomerulonephritis (MPGN), and 5 (13.5%) mesangioproliferative glomerulonephritis (MeGN). Clinico-pathological data were not associated with any type of ICGN. Among cats with non-ICGN, 11 (35.5%) had end-stage CKD, 9 (29%) focal segmental glomerulosclerosis, 6 (19.4%) global and multifocal mesangiosclerosis, 2 (6.5%) glomerular atrophy, 2 (6.5%) renal dysplasia and 1 (3.1%) amyloidosis. Eight (25.8%) cats with non-ICGN had chronic interstitial nephritis (CIN) grade 1, 13 (41.9%) grade 2 and 10 (32.3%) grade 3; creatinine and UPC ratio increased with CIN grades (p = 0.001, p < 0.001). Cats with ICGN were more frequently FIV or FeLV-infected (OR:11.4; 95%CI:1.4-94.4; p = 0.024), had higher UPC ratio (OR:6.8; 95%CI:2.5-18.2; p < 0.001) and were younger (OR:0.9; 95%CI:0.7-1.0; p = 0.042) than cats with non-ICGN.

CONCLUSIONS

MGN and MPGN were the most common morphological diagnoses of ICGN in cats. Unfortunately, none of the investigated findings differentiated ICGN morphological diagnoses. Serum creatinine concentration and UPC ratio were directly associated with grades of CIN (p = 0.001 and p < 0.001, respectively), confirming previous literature. More ICGN than non-ICGN was observed in cats with retroviral infections, younger cats and higher UPC ratio.

A rare case of patent ductus arteriosus in a dog with glomerular mesangiolysis

Rare case of patent ductus arteriosus (PDA) was observed in a 2-year and 9 month-old Miniature Dachshund which had been diagnosed as severe cardiac failure. Pulmonary artery from the right ventricle connected to dilated ductus arteriosus, and pulmonary artery-ductus arteriosus-descending aorta formed a continuous duct, which seemed to be the main route of bloodstream. Ascending aorta from the left ventricle was hypoplastic, and connected to the dilated ductus arteriosus. Glomerular mesangiolysis due to heart failure was also observed in the kidney.

Renal glomerular fibrosis in two pigs

Massive deposition of collagen fibrils was found in the renal glomeruli of two pigs. The affected pigs were a 6-month-old female hybrid pig with systemic mycobacteriosis and a retired sow showing azotemia. Microscopically, various amounts of a homogeneous eosinophilic substance were deposited within the expanded mesangium of almost all renal glomeruli in both cases. The deposit was also seen occasionally on the glomerular capillary walls in the sow. Capillary lumens were occluded in the glomerular segments with heavy deposition. Obsolescent glomeruli were often surrounded by lymphoid cells. The deposited substance was Congo red negative and stained deep blue with Heidenhain's azan staining. Immunohistochemical evaluation revealed that the major component of the homogeneous substance was type-III collagen. Electron microscopic examination showed that the deposits were masses of fibrils of variable length, width, and shape. The fibrils had transverse bands with a periodicity of approximately 60 nm, consistent with collagen fibrils. These glomerular changes were identical to those of collagenofibrotic glomerulonephropathy that has recently been described as a new glomerular disease in humans. The glomerular lesion may be the result of unusual production of type-III collagen by mesangial cells.