Analysis of ultrastructural glomerular basement membrane lesions and podocytes associated with proteinuria and sclerosis in Osborne-Mendel rats with progressive glomerulonephropathy

The renal glomeruli of 12 male Osborne-Mendel (OM) rats 3 to 24 weeks old were examined by electron microscopy. Effacement of podocyte foot processes (FPs) developed at 3 weeks of age and became progressively worse over time. Loss or dislocation of the slit membrane was also found. Vacuoles and osmiophilic lysosomes appeared in the podocytes starting at 6 weeks of age. Podocyte detachment from the glomerular basement membrane (GBM) was apparent at 18 weeks of age. Laminated GBM was occasionally observed in all animals. These features might lead to the development of spontaneous proteinuria and glomerulosclerosis in OM rats.

Crescentic glomerulonephritis: A clinical and histomorphological analysis of 46 cases.

Background: Crescentic glomerulonephritis (CrGN), defined as crescents involving more than 50% of the glomeruli, includes pauci-immune, immune complex-mediated and anti-glomerular basement membrane disease. Objectives: The present study was aimed at evaluating the various clinical, biochemical and histological parameters in CrGN with respect to these categories and clinical outcome. Materials and Methods: Renal biopsies diagnosed as CrGN between Jan 2008 and Feb 2010 were included. Clinical and laboratory parameters were retrieved along with the therapeutic approach and clinical outcome, wherever available. Renal biopsy slides were evaluated for various glomerular, tubulo-interstitial and arteriolar features. Appropriate statistical tests were applied for significance. Results: A total of 46 cases of CrGN were included; majority (71.7%) of cases were pauci-immune (PI) while 28.3% were immune complex-mediated (IC). Among clinical features, gender ratio was significantly different between PI and IC groups (P = 0.006). The various histological parameters, including proportion of cellular crescents, tuft necrosis and Bowman's capsule rupture, were similar in both the groups. Four unusual associations, including idiopathic membranoproliferative glomerulonephritis (MPGN), multibacillary leprosy, acute lymphoblastic leukemia and C1q nephropathy were detected. Adequate follow-up information was available in 21 (46%) of the patients. Of these, 11 (52.4%) were dialysis-dependent at the last follow-up. Adult patients required renal replacement therapy more frequently than pediatric cases (P = 0.05). Presence of arteriolar fibrinoid necrosis also showed association with poor clinical outcome (P = 0.05). Conclusions: Crescentic glomerulonephritis remains one of the main causes of acute renal failure with histological diagnosis. Immunohistologic examination is essential for accurate classification into one of the three categories. This condition should be considered in rare causal associations like leprosy or MPGN with renal failure, to allow for timely performed renal biopsy and appropriate aggressive therapy.

Familial lecithin-cholesterol acyltransferase deficiency

Familial lecithin-cholesterol acyltransferase deficiency is an uncommon autosomal recessive disorder from a heritable defect in esterification of plasma cholesterol. In 1968, the disease was described by Gjone and Norum in Norway. Our case was a 38-year-old woman. Her disease was manifested by presence of lower extremities edema, proteinuria, corneal opacities, increased plasma cholesterol, and hemolytic anemia. Suspicion of the disease was based on renal biopsy, which revealed mesangial expansion and capillary wall widening with clusters of foamy cells in the mesangium. Immunofluorescence study was nonspecific, but specific findings of electron microscopy showed deposition of lipid in the glomerular basement membrane and mesangium. This is the first report of lecithin-cholesterol acyltransferase deficiency in Iran. The diagnosis was confirmed by a low high-density lipoprotein cholesterol concentration, decreased activity of lecithin-cholesterol acyltransferase in plasma, and positive familial history of the disease

The number of podocyte and slit diaphragm is decreased in experimental diabetic nephropathy

OBJETIVO: Determinar o número de podocitos e fendas diafragmáticas, a extensão das fendas diafragmáticas e a espessura da Membrana Basal Glomerular (MBG) na nefropatia diabética. MÉTODOS: Sessenta "Rattus Wistar" de ambos os sexos, pesando entre 200-300g, foi dividido em dois grupos experimentais: grupo normal 10 animais, e grupo diabético induzido por aloxana – 50 animais. A Aloxana foi administrada em dose única endovenosa de 42mg/kg de peso. Medimos o peso, ingestão de água e comida, diurese e glucose sérica e urinária em ambos os grupos antes da injeção de aloxana e 2 (duas) semanas, seis e dose meses após a injeção. A proteinúria foi mensurada aos dose meses em ambos os grupos, no momento do sacrifício, onde removemos o rim direito para estudo ultraestrutural. RESULTADOS: Observamos sinais clínicos e laboratoriais de diabetes severo, nos animais diabéticos aloxânicos em todos os períodos de seguimento. Foi determinado o espessamento da membrana basal glomerular (MBG), número de podocitos, número de fendas diafragmáticas e sua extensão. A membrana basal glomerular do rato diabético mostrou espessamento significativo (mediana=0.29µm; amplitude semi-interquartilica = 0,065µm) em relação ao animal normal (0,23µm; 0,035µm). O número de podocitos do animal diabético (8; 1), número de fenda diafragmática (4; 1), e extensão das fendas diafragmáticas (0,021µm; 0,00435µm) foi significativamente menor em relação aos animais normais (11; 1) e (7; 1.5), e (0,031µm; 0,0058µm). A taxa da proteinúria (0,060mg/24h; 0,037mg/24h) foi maior que nos animais normais (0,00185mg/24h; 0,00055mg/24h). CONCLUSÃO: O diabetes experimental está associado com significativas alterações (p< 0,05) no número de processos podálicos e fendas diafragmáticas e extensão das fendas diafragmáticas e espessamento da membrana basal glomerular (MBG).