Quantitative characterization of glomerular fibrosis with magnetic resonance imaging: a feasibility study in a rat glomerulonephritis model.

Glomerular fibrosis occurs in the early stages of multiple renal diseases, including hypertensive and diabetic nephropathy. Conventional assessment of glomerular fibrosis relies on kidney biopsy, which is invasive and does not reflect physiological aspects such as blood perfusion. In this study, we sought to assess potential changes of cortical perfusion and microstructure at different degrees of glomerular fibrosis using magnetic resonance imaging (MRI). A rat model of glomerular fibrosis was induced by injecting anti-Thy-1 monoclonal antibody OX-7 to promote mesangial extracellular matrix proliferation. For six rats on day 5 and five rats on day 12 after the induction, we measured renal cortical perfusion and spin-spin relaxation time (T2) in a 3-Tesla MRI scanner. T2 reflects tissue microstructural changes. Glomerular fibrosis severity was evaluated by histological analysis and proteinuria. Four rats without fibrosis were included as controls. In the control rats, the periodic acid-Schiff (PAS)-positive area was 22 ± 1% of total glomerular tuft, which increased significantly to 56 ± 12% and 45 ± 10% in the day 5 and day 12 fibrotic groups, respectively ( P < 0.01). For the three groups (control, day 5, and day 12 after OX-7 injection), cortical perfusion was 7.27 ± 2.54, 3.78 ± 2.17, and 3.32 ± 2.62 ml·min-1·g-1, respectively, decreasing with fibrosis severity ( P < 0.01), and cortical T2 was 75.2 ± 4.6, 84.1 ± 3.0, and 87.9 ± 5.6 ms, respectively ( P < 0.01). In conclusion, extracellular matrix proliferation in glomerular mesangial cells severely diminished blood flow through the glomeruli and also altered cortical microstructure to increase cortical T2. The MRI-measured parameters are proven to be sensitive markers for characterizing glomerular fibrosis.

IgA nephropathy featuring massive wire loop-like deposits in two patients with alcoholic cirrhosis.

BACKGROUND: Various renal manifestations are known to develop in patients with liver disease, including chronic hepatitis and cirrhosis. CASE PRESENTATION: We evaluated renal disease in two 47-year-old Japanese men with liver cirrhosis and chronic alcoholism for 34 years and 27 years, respectively. Renal biopsy demonstrated massive wire loop-like deposits in the subendothelial space of the glomerular basement membrane and in the mesangium. However, immunofluorescence was only positive for IgA and C3, and electron microscopy did not reveal any organized structures in the electron-dense deposits. IgA nephropathy was diagnosed, although the features were different from primary IgA nephropathy. Both patients had portosystemic shunts associated with liver cirrhosis. Their renal deposits and proteinuria resolved completely after 1 year of steroid therapy. CONCLUSION: Alcohol abuse may have contributed to development of secondary IgA nephropathy in these two patients, probably via their portosystemic shunts.

Prenatal findings in four consecutive pregnancies with fetal Pierson syndrome, a newly defined congenital nephrosis syndrome.

OBJECTIVE: To describe the prenatal findings in Pierson syndrome, a newly defined autosomal recessive entity, comprising congenital nephrotic syndrome (CNS) with diffuse mesangial sclerosis and distinct eye abnormalities due to LAMB2 mutations. METHODS: Serial prenatal ultrasound examinations were performed in four consecutive pregnancies affected by Pierson syndrome in the same family. LAMB2 mutations were demonstrated in retrospect by direct sequencing of the gene in the newborn index patient and three abortuses. RESULTS: Fetal ultrasound consistently revealed marked renal hyperechogenicity associated with variable degree of pyelectasis. These features were detectable by 15 weeks of gestation in all fetuses. Hydrops fetalis due to severe hypalbuminemia demonstrated by chordocentesis occurred in one fetus. Placentas were significantly enlarged. Development of oligohydramnios indicated prenatal decline of renal excretory function. Anencephaly was detected in another fetus with molecularly proven Pierson syndrome at 12 weeks of gestation. CONCLUSION: We conclude that Pierson syndrome has to be considered in the differential diagnosis of nephrotic disorders with prenatal onset. Ultrasound criteria for differentiation from the most common type of CNS-congenital nephrosis of the Finnish type (CNF)-are discussed. Because of its prognostic relevance, we advocate molecular genetic testing of LAMB2 in any case of prenatally detected nephrotic syndrome with negative results of NPHS1 mutational screening, especially in the presence of the typical sonomorphologic findings of the kidneys and the development of oligohydramnios.