Spontaneous early-onset glomerulonephritis in a 8-week-old male Crj:CD1 (ICR) mouse

Glomerular lesions including membranoproliferative glomerulonephritis occur spontaneously in aged mice, but they are rare in young animals. In our laboratory, spontaneous glomerulonephritis was observed in an 8-week-old male Crj:CD1 (ICR) mouse. Macroscopically, the bilateral kidneys were discolored, but no edema or ascites was observed. Glomerular lesions were characterized by a thickening of capillary walls, a double-contoured basement membrane and mesangial expansion due to increased amounts of matrix. Ultrastructurally, mesangial interposition in the capillary wall and subendothelial deposition of basement membrane-like material were observed. No evidence of immune complex deposition or amyloid was found. On the basis of the observed clinical pathology and histopathology, a secondary form of glomerular lesion was excluded. The glomerular lesion was compatible with glomerulonephritis in a young Crj:CD1 (ICR) mouse.     

Mesangioproliferative Glomerulonephritis in Mink with Encephalitozoonosis

Renal specimens from 6 mink with encephalitozoonosis were studied by light and electron microscopy and immunohistochemistry. The glomeruli of affected kidneys had a mesangioproliferative glomerulonephritis which was characterized by an increase in mesangial cells and matrix in most glomeruli. Some glomeruli were partially or completely sclerosed. There were protein or granular casts in the cortical and medullary tubules. Interstitial nephritis, vasculitis and tubular cysts were found. Electron microscopy demonstrated extensive matrix and increased cellularity in the mesangial areas. Glomeruli showed segmentally thickened or wrinkled capillary basement membranes. Electron dense deposits were found in the glomerular basement membranes and mesangium. Peroxidase-anti-peroxidase immunohistochemistry demonstrated that IgG and IgM positive material was present as granular deposits in the glomerular basement membrane and occasionally in the mesangium.     

The distribution of renin in the segments of the renal arterial tree in cats: an immunohistochemical and ultrastructural study

The intrarenal distribution of renin in the cat kidney was evaluated in a semi-quantitative immunocytochemical study using a cross-reacting antiserum directed against purified renin. In addition, the morphology of the juxtaglomerular apparatus was studied electron-microscopically. The majority of renin in the cat kidney was located in the distal portion of the afferent arteriole. The values for the juxtaglomerular index and the renin-positive portion of the afferent arteriole were 30.6 +/- 3.2% and 49.9 +/- 8.3 microns, respectively. In addition, scattered renin-positive cells were found far from the vascular pole and even in the interlobular artery. Also, some vasa efferentia contained renin-positive cells. In 70% of the cats studied, renin-positive cells were located in the glomerular mesangium. The majority of the renin-positive mesangial cells were located in the vicinity of the glomerular stalk, but in some cases the centrilobular mesangium also contained renin-positive cells.     

Membranous glomerulonephritis in dogs infected with Dirofilaria immitis.

Membranous glomerulonephritis was diagnosed in five dogs with patent Dirofilaria immitis infections. Electron-dense deposits were present on the epithelial side of the glomerular basement membrane. An immunofluorescent study demonstrated immunoglobulins in the capillary wall and mesangium of the glomeruli. The glomerular lesions were considered to represent an immune complex form of glomerulonephritis induced by the D. immitis infection.     

Spontaneous mesangiocapillary glomerulonephritis in Finn cross lambs from Alberta.

A spontaneous mesangiocapillary glomerulonephritis occurred in three, one to three month old Finnish Landrace cross lambs from a flock in northern Alberta. The ram was a purebred Finn sheep, and the ewes were Finn-Rambouillet and Finn-Suffolk-Rambouillet crosses. The lambs were found dead without previous clinical signs. Histologically there was marked thickening of glomerular capillary basement membranes, proliferation of mesangial cells, and peri-glomerular fibrosis. An interstitial infiltration of plasma cells and lymphocytes was present with occasional tubular degeneration and proteinaceous cast formation. Focal leukoencephalomalacia was present in one lamb. Electron microscopy demonstrated deposition of electron-dense deposits in a subendothelial location with occasional fusion of overlying foot processes in glomerular capillaries. Indirect immunofluorescence studies demonstrated positive staining material in glomerular capillary walls. These findings in Finnish Landrace cross lambs are characteristic of mesangiocapillary glomerulonephritis, a condition heretofore not reported in North America.     

Glomerular lesions in renal biopsies of Saimiri boliviensis (primate) examined by light and electron microscopy and immunohistochemistry

In order to determine the existence of glomerular lesions in Saimiri boliviensis, renal biopsies were performed in 20 clinically healthy animals of similar age and both sexes. Biopsies were obtained by laparotomy with a Tru-Cut biopsy needle. Mesangioproliferative glomerulonephritis characterized by an increased number of mesangial cells and increased mesangial matrix was present in 35% of the animals. Proliferative glomerulonephritis characterized by increased numbers of epithelial and endothelial cells with narrowed capillary lumen, and membranous glomerulonephritis characterized by diffuse thickening, wrinkling, and occasional lamellation of basement membranes, were present in 15% of the samples. Ultrastructural features included increased mesangial matrix, fusion of the visceral epithelial foot processes, thickened glomerular basement membranes, and incipient lamellation. Immunohistochemical examination revealed granular deposits of immunoglobulin M in the cytoplasm of mesangial cells and in the mesangial matrix in 50% of the samples.     

Glomerulonephritis associated with simultaneous canine adenovirus-1 and Dirofilaria immitis infection in a dog

This article describes a case of glomerulonephritis and immunocomplex (IgM, IgG and C3c) deposition in the mesangium and basement membranes of a 2-year-old dog with canine viral hepatitis and dirofilariasis. The deposits observed in the mesangium were in the vicinity of cells with viral replication. However, no clear relationship was found between viral replication and the deposition of immunocomplexes in the glomerular capillary basement membranes, which may be the reason why these deposits have only been tentatively related to the concomitant infestation by Dirofilaria immitis.     

Canine glomerulonephritis: new thoughts on proteinuria and treatment

Glomerular disease in the dog is not only a common form of renal disease but also an important cause of chronic renal failure. The presence of immune complexes in glomerular capillary walls is a major cause of canine glomerular disease and is commonly referred to as glomerulonephritis. Leakage of plasma proteins, principally albumin, across the damaged glomerular capillary walls results in persistent proteinuria--the clinicopathological hallmark of glomerulonephritis. Recent evidence suggests that, in addition to being a marker of disease, persistent proteinuria is associated with progressive glomerular and tubulointerstitial lesions and loss of additional nephrons. Perhaps the best treatment for glomerulonephritis is the identification and correction of any underlying inflammatory, immune-mediated or neoplastic disease that results in the deposition or formation of glomerular immune complexes. In cases of idiopathic glomerulonephritis, angiotensin-converting enzyme inhibitors have been shown to decrease proteinuria and potentially slow disease progression.     

Glomerulonephritis Associated with Simultaneous Canine Adenovirus‐1 and Dirofilaria immitis Infection in a Dog

This article describes a case of glomerulonephritis and immunocomplex (IgM, IgG and C3c) deposition in the mesangium and basement membranes of a 2‐year‐old dog with canine viral hepatitis and dirofilariasis. The deposits observed in the mesangium were in the vicinity of cells with viral replication. However, no clear relationship was found between viral replication and the deposition of immunocomplexes in the glomerular capillary basement membranes, which may be the reason why these deposits have only been tentatively related to the concomitant infestation by Dirofilaria immitis.     

Murine cytomegalovirus glomerulonephritis: clinical and ultrastructural observations.

This investigation was initiated to study and correlate the clinical and ultrastructural aspects of glomerulonephritis induced in the laboratory mouse by the intraperitoneal injection of a sublethal dose of murine cytomegalovirus. An attempt was made to ascertain the pathogenesis of the glomerular changes and the resultant viremia. Murine cytomegalovirus infection caused an acute transient glomerulonephritis in young female mice of the HA/ICR strain. Mice that survived a sublethal inoculation of homogenized infected gland developed transient proteinuria and excreted tubular casts. The murine cytomegalovirus infection resulted in a glomerular lesion that was selective for the mesangial cell. After entering the mesangial cell by phagocytosis the virus replicated in the nucleus and was excreted into the channel of the mesangial matrix, with extension toward the periphery of the capillary loop and adjacent to the urinary space. Virus particles were rarely found in the glomerulus after the 5th day of infection and chronic renal disease was not observed.     

Noncongophilic fibrillary glomerulonephritis in a cat

This report describes an uncommon case of nonamyloidotic fibrillary glomerulonephritis. A 5-year-old female European cat was presented with nephrotic syndrome. Serum biochemistry and urinalysis revealed a mild increase in cholesterol, low total protein, severe hypoalbuminemia, and high proteinuria with a high protein-to-creatinine ratio. An histologic examination revealed an interstitial nephritis and a diffuse glomerulonephritis, with multifocal thickening of the Bowman's capsule. Transmission electron microscopy showed widespread fibrillary deposits in the glomerular basement membrane and in the mesangium. These fibrils ranged between 18 and 26 nm in diameter and were Congo red negative, which allowed their differentiation from amyloid. Immunohistochemistry demonstrated expression for immunoglobulin M (IgM) and immunoglobulin G (IgG) within the mesangium. Renal deposits of Congo red-negative amyloid-like fibrils have been described in humans, horses, monkeys, and dogs. This is the first report of noncongophilic fibrillary glomerulopathy in a cat.     

Membranoproliferative glomerulonephritis possibly associated with over-vaccination in a cocker spaniel

Membranoproliferative glomerulonephritis was observed in a seven-month-old male cocker spaniel dog. The clinical, microbiological, biochemical, radiographic and ultrasonographic examinations ruled out neoplasia, congenital disease and infectious disease. The anamnesis revealed that the owner had vaccinated the dog seven times, one vaccination per month, without veterinarian supervision. In both kidneys, severe thickening of the glomerular capillary walls was observed. Electron microscope examination revealed a large number of electron-dense deposits that were primarily in the glomerular subendothelial spaces and the basal membrane, which is compatible with antigen-antibody complexes. The immunohistochemical examination revealed that the antigen present in the glomeruli corresponded with the antigen present in the vaccine. We report a type III hypersensitivity nephropathy in a young dog, which was possibly caused by over-vaccination.     

Electron microscopic structure of mesangioproliferative glomerulonephritis (MesPGN) in animals

In a murine lupus model, the kidneys of 42 MRL mice of different age groups (substrains MRL/Mp-lpr/lp and -+/+) were studied by light and transmission electron microscopy. The results demonstrate the ultrastructural feature of the mesangial-proliferative glomerulonephritis which is one of the observed forms of glomerulonephritis. The most important alterations are a severe proliferation of mesangial cells (with an increase in rough endoplasmic reticulum and mitochondria) and electron dense deposits in different sites of the glomerular basement membrane (subepithelial, subendothelial, intramembranous). These deposits are proposed to be immune complexes. Osmiophilic intracytoplasmic inclusions of the mesangial cells are indications of an altered renin production. Alterations of the glomerular epithelial cells are characterized by fusions of the epithelial pedicles, an increase of microvilli and intracytoplasmic concentrations of electron dense material which are also proposed to be immune complex deposits. The morphological feature of the mesangial-proliferative glomerulonephritis is completed by an activation and focal edema of endothelial cells. The described alterations are discussed and compared with findings in other species.     

Glomerular lesions associated with proteinuria in clinically healthy dogs.

Spontaneous proteinuria in otherwise clinically normal adult Beagles 4-6 years old was studied for 2 years. Eighteen dogs, representing a population of 218 Beagles, were placed into three groups: group I, nonproteinuric; group II, intermittently proteinuric; group III, persistently proteinuric. The groups were alike on the basis of laboratory tests, except urinary protein loss. Proteinuria was persistent in most affected dogs but not progressive during the 2 years. The loss of proteins with high molecular weight, including alpha-, beta-, and gamma-globulins, suggested the proteinuria was of glomerular origin. There were glomerular lesions but no other significant change in the kidneys and urogenital system. Lesions were generalized and characterized by prominent, local or diffuse mesangial proliferation and by thickening, wrinkling, and splitting of the glomerular basement membrane. The subendothelial space was often widened and contained electron-dense deposits. Similar electron-dense deposits, as well as lipid and mineral, were in the mesangium. Alterations in visceral epithelial cells and endothelium were prominent. Periglomerular sclerosis was present but tended not to correlate with the severity of mesangial change in any given renal corpuscle. The severity of both mesangial and periglomerular changes increased with increasing proteinuria. Immunofluoescence studies demonstrated granular discontinuous localization of IgG and betaIC-globulins in the glomerular capillaries and mesangium. Similar localization was seen but to a lesser extent in nonproteinuric dogs. The glomerular lesions seen in these clinically healthy, proteinuric dogs are similar to those described in various canind diseases associated with terminal renal failure.     

Spontaneous glomerulonephritis in dogs. II. Correlation of glomerulonephritis with age, chronic interstitial nephritis and extrarenal lesions

A morphologic study of 103 dogs, including two with renal amyloidosis, showed that different types of diffuse glomerulonephritis are correlated with different age groups. Membranous and membranoproliferative glomerulonephritis were more common in middle-aged and older animals, whereas mesangial lesions were found predominantly in younger dogs and considered to be early glomerular changes. Glomerulonephritis largely occurred independently of interstitial nephritis. The incidence of interstitial lesions was 71%. Chronic interstitial nephritis was rare in dogs under 1 year old. Glomerulonephritis did not seem to induce interstitial nephritis. Glomerulonephritis occurred not only in kidneys with severe interstitial damage, but also in those with slight damage. The indicated that glomerulonephritis occurred independently of interstitial nephritis. In end-stage kidneys with severe fibrosis, mesangial changes seemed to predominate.     

Renal lesions in MRL mice

Female MRL-Mp-lpr/lpr mice spontaneously develop autoimmune disease at three to five months of age and die most commonly from immune complex glomerulonephritis. Kidneys of two-month-old females appeared nearly normal by electron microscopy, and glomerular deposits of IgG an complement component 3 (C3) barely were detectable. In five-month-old females, immunofluorescence revealed numerous deposits of IgG and C3; glomerular mesangial cells were hypertrophic and hyperplastic and contained electron-dense material. There were subepithelial and subendothelial deposits of electron-dense material with swelling of epithelial cell cytoplasm. This disease has many features similar to the immune complex glomerulonephritis observed in New Zealand Black and White hybrid mice and in man.     

水貂脑胞内原虫病肾小球病理形态学研究

用光学、电子显微镜和免疫组织学方法对6只患有脑胞内原虫病的水貂肾脏进行了研究。结果表明,脑胞内原虫感染可引起水貂系膜增生性肾小球肾炎,其发生与免疫复合物颗粒在肾小球基膜和系膜区的沉积有密切关系。     

Pathological changes in kidneys of dogs with natural Leishmania infection.

A study was made of the nephropathy in canine leishmaniasis produced in ten adult dogs naturally infected with Leishmania infantum. Renal function analyses were performed (uraemia, creatinaemia, plasma proteins, biochemistry and urinary sediment), the humoral immune response (fluorescent antibodies and levels of serum IgG, IgM and IgA) was assessed and histopathological studies were carried out. Correlation of the results showed acute renal insufficiency which was reversible in two animals (endotheliomesangial glomerulonephritis) and irreversible in four cases corresponding to glomerulonephritis in its Type I and Type II proliferative forms; extensive increase in the glomerular basal membrane, proliferation of mesangial cells and growth of the mesangial matrix were observed, as was a widespread incidence of immune complex deposits. Two animals showed chronic renal insufficiency. Lack of renal changes (minimal-changes glomerulonephritis) in two dogs was accounted for in one animal by an almost complete absence of symptoms and in the other by chronic viscerocutaneous symptoms; neither showed more than a slight immunoglobulin response.     

Glomerular lesions in unilateral nephrectomized and diabetic (UN-D) mice.

Experimental diabetes was induced in both control and unilaterally nephrectomized male mice by injecting streptozotocin (SZ) (50 mg/kg x 5 days) one week after nephrectomy. The time course changes in the glomerular lesions were examined for up to 12 weeks after completion of the SZ-injection (12WAI). In unilateral nephrectomized and diabetic mice, mild segmental expansion of the mesangial area developed at 4WAI, and it progressed to prominent segmental glomerulosclerosis at 12WAI. In the electron microscopic examination at 12WAI, marked expansion of the mesangial area, segmental thickening of the glomerular basement membrane, fusion of the foot processes of podocytes and a prominent increase in the number of microvilli of capillary endothelial cells were observed. On the other hand, mild to moderate expansion of the glomerular mesangial area was only sporadically found in unnephrectomized diabetic mice at 12WAI. Interestingly, Bowman's capsules of diabetic mice were generally lined with flattened epithelia but those of non-diabetic mice with cuboidal or low columnar epithelia.     

Peculiarities of the Connection between Mesangial and Glomerular Endothelial Cells in the Domestic-swine Kidney

It is established that cytoplasm fragments of the endothelial cells, located between the mesangial angles, abruptly extend their size, and borders between them are difficult to discern. They possess single microvillia on their lumenal surface, some of which are highly corrugated, branched and fenestrated. In those parts, the mesangial-cell excrescences are tightly enveloped by the endothelium, some of them contacting directly with the capillary lumen. On the border between the mesangium and the juxtamesangial part of the endothelium, two types of vesicles, directed towards the capillary lumen, are observed. The first type of vesicle is bigger and has a deeply narrowing section, which is directed towards the mesangium. The second type of vesicle is enveloped by a two-layer membrane, which, in almost all cases, is connected to the endothelium. Peculiarities in the localization of the podocyte excrescences are also detected, which gives reason to presume that the epithelial cells play an important part in the biomechanics of the renal glomerulus.