Protein restriction ameliorates renal tubulointerstitial nephritis and reduces renal transforming growth factor-beta expression in unilateral ureteral obstruction

In contrast to the substantial evidence for attenuation of the glomerular lesions by a low-protein (LP) diet, it remains to be determined whether and how such a diet lessens the progression of tubulointerstitial lesions, which show the strongest correlation with renal function. Chronic unilateral ureteral obstruction (UUO) results in interstitial fibrosis of the affected kidney. We investigated the therapeutic effects of an LP diet on the progression of interstitial fibrosis in UUO mice. Sixty ICR mice underwent UUO or sham operation; half of these mice were fed a normal-protein (NP) and the other half a LP diet. They were sacrificed at 3, 7 and 14 days postoperatively. The degree of tubular lesion, the distribution of transforming growth factor-beta (TGF-beta), alpha-smooth muscle actin and fibronectin and the activated TGF-beta 1 level were determined. The LP diet significantly reduced the progression of tubular injury, depositions of fibronectin, tubulointerstitial myofibroblast formation, the interstitial expression of TGF-beta-positive cells (at 14 days; NP = 6.91 +/- 3.35 vs. LP = 1.67 +/- 0.41; p < 0.005), and renal active TGF-beta 1 concentration (at 14 days; NP = 5.72 +/- 2.03 vs. LP = 2.96 +/- 0.72; p < 0.01). We conclude that protein restriction may aid the attenuation of progression of tubulointerstitial fibrosis through the reduction in tubulointerstitial expression of TGF-beta.

Bile acid extraction rate in the liver of cows fed high-fat diet and lipid profiles in the portal and hepatic veins

The purposes of this study are to assess the responses of increased supplemental dietary fat in the cow, without upsetting rumen fermentation, on the bile acid (BA) extraction rate in the liver and to determine whether this diet would affect the postprandial lipid profiles in the portal and hepatic venous blood. Six Holstein cows were equipped with catheters fitted in the portal and hepatic veins. Two cows each were assigned randomly to a sequence of three dietary treatments of 21-day period. The methodology of this study was based on the supplementation of the basal concentrate diet with 0 (control), 5, or 10% calcium salts of fatty acids (CSFA). The total bile acids were significantly increased in the portal and hepatic veins with the 5% CSFA diet, whereas no increase occurred with the 10% CSFA diet. Data obtained in this study showed that 10% CSFA diet failed to stimulate BA secretion to exceed the values obtained with 5% CSFA-diet. Moreover, there was no change in the hepatic extraction rate of BA in animals fed either the 0 or 5% CSFA diets which ranged from 2.4 to 6.5-fold and 3.1 to 7.3-fold, respectively. However, the extraction rate increased sharply with the 10% CSFA diet (27-fold). The median portal and hepatic concentrations of total lipids, triglycerides, total cholesterol, phospholipids and non-esterified fatty acids did not show any significant increase during feeding of the control diet. Moreover, feeding either the 5 or 10% CSFA diet did not significantly increase these values in either vein.

Enzyme immunoassay for conjugated 7alpha-hydroxy-3-oxo-4-cholenoic acid in human urine

A microplate enzyme immunoassay (EIA) was developed for the measurement of glycine- and taurine-conjugated 7alpha-hydroxy-3-oxo-4-cholenoic acids (CDCA-delta4-3-one) in human urine. The antiserum was prepared by immunizing rabbits with N-(7alpha-hydroxy-3-oxo-4-cholen-24-oyl)-3-aminopropionic acid--bovine serum albumin conjugate. A colorimetric EIA was established using horseradish peroxidase-labeled antigen having a shorter bridge length than that of the immunogen, and 3, 3', 5, 5'-tetramethylbenzidine /hydrogen peroxide for the measurement of the enzyme activity. The reactivities of the antiserum for glycine and taurine conjugates of CDCA-delta4-3-one was almost the same. The specificity of the antiserum was investigated by determining the cross-reactivities of various bile acids and related compounds. An appropriate dose-response curve for conjugated CDCA-delta4-3-one was obtained in the range of 0.05-10 ng/well. This method was used for direct analysis of conjugated CDCA-delta4-3-one in urine of healthy infants and patients with liver diseases.

Linkage mapping of the mouse nephrosis (nep) gene to chromosome 15

ICGN is a partially inbred strain of mice with nephrotic syndrome caused by spontaneous glomerular lesion. It has been reported that the albuminuria in ICGN mouse was controlled by at least a single autosomal recessive gene (nep). In this study, we mapped the nep locus by linkage analysis of backcross progeny between ICGN and MSM mice using DNA pooling method. The linkage analysis revealed that the nep locus was localized on the distal part of chromosome 15.

Polymorphisms in the platelet-endothelial cell adhesion molecule-1 (PECAM-1) gene, Asn563Ser and Gly670Arg, associated with myocardial infarction in the Japanese

We examined three missense polymorphisms of platelet-endothelial cell adhesion molecule-1 (PECAM-1), Val125Leu, Asn563Ser, and Gly670Arg, in 136 Japanese patients with myocardial infarction and 235 healthy Japanese controls. We found that these polymorphisms were in linkage disequilibrium with each other and that frequencies of 125Leu, 563Ser, and 670Arg alleles were significantly increased in patients compared with controls (0.522 vs 0.447, p = 0.048; 0.585 vs 0.502, p = 0.030; and 0.577 vs 0.492, p = 0.032, respectively). The frequencies of homozygotes for 563Ser and 670Arg alleles were also significantly increased in the patients (33.1% vs 23.4%, odds risk [OR] = 1.62, p = 0.040, 95% confidence interval [95%CI] = 1.01-2.58; and 32.4% vs 23.0%, OR = 1.60, p = 0.048, 95%CI = 1.00-2.57, respectively). These observations suggest that the 563Ser/Ser genotype and 670Arg/Arg genotype of PECAM-1 are novel genetic risk factors of myocardial infarction in Japanese. Stratification analysis of the patients showed that the associations of these PECAM-1 genotypes with myocardial infarction were preferentially found in male and younger patients (age of onset of myocardial infarction less than 60 years). In addition, the associations were stronger in patients with three-vessel disease than in the others and appeared independent of conventional risk factors including smoking, hypertension, diabetes mellitus, hyperlipidemia, and obesity.

An experimental study on radiation streaming through a labyrinth in a proton accelerator facility of intermediate energy

A radiation streaming experiment has been carried out at the Takasaki Ion Accelerator Facility for Advanced Radiation Application at the Japan Atomic Energy Research Institute in a room housing a Cu target irradiated with 68 MeV protons and in a labyrinth of three-legs having a total length of 29 m. In the experiment, neutron and gamma ray energy spectra, neutron reaction rates, and neutron and gamma ray dose equivalent rates were measured using various counters and dosimeters. The experimental data show the applicability of some empirical formulas for estimating the thermal neutron flux in a room and neutrons streaming in a labyrinth designed for a proton accelerator operating in the intermediate energy region. The data suggest that it is mandatory to estimate the gamma ray dose equivalent rate in a labyrinth, which is dominated by the secondary gamma rays due to the neutron capture reaction.

Microbiological contamination in genetically modified animals and proposals for a microbiological test standard for national universities in Japan

The Biosafety Committee of the Japanese Association of Laboratory Animal Facilities of National Universities (JALAN) investigated recent episodes of microbiological contamination in genetically modified mice (GMM), and the countermeasures taken when the contaminated GMM were introduced into animal facilities, by questionnaires addressed to 53 animal facilities belonging to JALAN and serological tests. Although almost all of the contaminated GMM were accepted with conditions such as rederivation after or before reception and housing in designated rooms, contamination with a spectrum of microorganisms was demonstrated in GMM transferred domestically and from abroad. In serological tests, Mycoplasma pulmonis, mouse parvovirus, and mouse encephalomylitis virus were detected in GMM transferred from domestic facilities and from abroad. The present results of the questionnaires and serological tests suggest that GMM are highly and widely contaminated with microorganisms compared with mice from commercial breeders. Thus, we propose a microbiological requirement, including microbiological status--excellent, common, and minimum--as a guide for the transfer and procurement of mice and rats in Japan.

3beta-hydroxy-delta5 -C27-steroid dehydrogenase deficiency: diagnosis and treatment

The aim of this study was to evaluate the effects of bile acid treatment and to obtain further information about the pathway of bile acid biosynthesis in a patient with 3beta-hydroxy-delta5-C27-steroid dehydrogenase/isomerase (3beta-HSD) deficiency by gas chromatography-mass spectrometry. Results showed that at 2 months of age, 3beta-hydroxy-5-cholen-24-oic acid (3.0 micromol/mmol Cr, 7.9%) was detected in the urine in essentially the same relative amount as 3beta,7alpha-dihydroxy- and 3beta,7alpha,12alpha-trihydroxy-5-cholen-24-oic acids (3.7 micromol/mmol Cr, 9.8%) during ursodeoxycholic acid treatment combined with prednisolone. As a result, diagnosis was delayed until 18 months of age. One month later with substitution of chenodeoxycholic acid treatment, urinary 3beta,7alpha-dihydroxy- and 3beta,7alpha,12alpha-trihydroxy-5-cholen-24-oic acids decreased significantly, and subsequent improvement of liver dysfunction was accelerated. Chenodeoxycholic acid treatment is useful in 3beta-HSD deficiency. However, in the diagnosis of this disease in early life, it should be noted that the acidic pathway may be the major route for bile acid biosynthesis in the neonatal period. Diagnosis of 3beta-HSD deficiency may have been delayed by administration of ursodeoxycholic acid, resulting in prolonged diagnostic investigation in this child with cholestasis. Further, use of prednisolone may have been contraindicated.

Metabolic changes in human CD36 deficiency displayed by glucose loading

Previous in vitro studies have shown that CD36 participates in cellular fatty acid (FA) uptake. In vivo evidence for a physiologic role of CD36 in this process is poor and mostly obtained in animals. To examine the metabolic role of human CD36, we performed a glucose loading test for normals (n = 16) and subjects with CD36 deficiency, both Type I (n = 5) and Type II (n = 16). After 30 min, FA levels had fallen by 60.1% in normals but by only 31.7% in Type II deficiency (P <0.01 vs. normals) and 16.5% in Type I deficiency which remained significantly higher than the other two groups out to 2 h. Further, changes in triglyceride and glucose metabolism were observed in the both types of CD36 deficiency. Impaired fast FA clearance by muscle and consequently increased hepatic FA uptake seem to underlie these changes. We conclude that human CD36 deficiency causes systemic metabolic changes.

Comparison of intact PTH assay and whole PTH assay in long-term dialysis patients

Adynamic bone disease has become a major problem in long-term dialysis patients. It has been suggested that higher levels of parathyroid hormone (PTH) are needed to maintain normal bone turnover in uremia. PTH levels currently are evaluated routinely by intact PTH assay, which may detect inactive 7-84 PTH fragments as well as 1-84 PTH. We examined the efficacy of whole PTH assay, which detects 1-84 PTH exclusively, in 99 nondiabetic patients on maintenance dialysis for more than 10 years, without any residual renal function. PTH levels determined by whole PTH assay were lower than those determined by intact PTH assay in all cases. Serum markers of bone metabolism, such as serum activity of bone alkaline phosphatase, correlated well with whole PTH levels. Because 7-84 PTH has been shown to inhibit the effects of 1-84 PTH, the biologic activity of circulating PTH in uremic patients may be much lower than the values assayed by conventional intact PTH assay. Despite an attempt to correlate 1-84 PTH/7-84 PTH ratio with bone histology, we could find only 1 patient out of 99 with 1-84 PTH/7-84 PTH ratio less than 1, which has been suggested to be indicative of low turnover bone. A cutoff value of this ratio should be set in the future for patients with a long hemodialysis history, with various modes of medical therapy.

Usefulness of BMIPP SPECT to evaluate myocardial viability, contractile reserve and coronary stenotic progression after reperfusion in acute myocardial infarction

Using combined 123I-BMIPP (BMIPP), 201Tl (Tl) and 99mTc-PYP (PYP) myocardial SPECT imaging, risk areas of acute myocardial infarction were documented in the acute stage, and then these images were evaluated for how well they reflected muscle viability, contractile reserve and coronary stenotic progression subsequent to reperfusion therapy. Patients who only experienced a first attack of myocardial infarction were enrolled. In total, 36 cases who had had the occluded artery successfully reperfused were examined during the past year. They had no significant vessel disease except for the culprit single artery. The patients were comprised of 32 men and 4 women. The mean age was 59.5 years. All patients underwent coronary angiography and left ventricular (LV) angiography in the emergency room. BMIPP/Tl and PYP myocardial SPECT were conducted in the acute stage and chronic stage. In the chronic stage LV angiography was repeated to assess the improvement of LV wall motion. The response to postextrasystolic potentiation (PESP) testing was performed to estimate myocardial contractile reserve. The risk area of acute myocardial infarction (AMI) was documented by reduced BMIPP accumulation. The size of reduced BMIPP accumulation was larger than that of PYP accumulation. A BMIPP/Tl discrepancy and PYP accumulation were documented to assess myocardial viability. Both improvement in LV wall motion and augmentation of PESP response were more closely related to a BMIPP/Tl discrepancy in the presence or absence of PYP accumulation. Therefore, it would be possible to evaluate myocardial viability and contractile reserve by the BMIPP/Tl discrepancy. In patients with good viability, it is important to predict whether there is coronary stenotic progression or not. In this study, we demonstrated that most patients with improved BMIPP images had no significant progression at the site of intervention. Serial observation of BMIPP images from the acute stage to the chronic stage might enable us to predict the progression of coronary stenosis.

Immunohistochemical evaluation of a malignant phecochromocytoma in a wolfdog

A malignant pheochromocytoma with multiple metastases was diagnosed in a 7-year-old male wolfdog that resulted from a cross between an eastern timber wolf (Canis lupus lycaon) and an Alaskan malamute. A yellowish white neoplastic mass approximately 10 cm diameter was found in the right adrenal gland. The neoplasm penetrated through the wall of the caudal vena cava. A diagnosis of pheochromocytoma was established by histopathologic and immunohistochemical procedures. Immunohistochemically, the neoplastic cells expressed chromogranin A, substance P, synaptophysin, Leu-7, protein gene product 9.5, methionine-enkephalin, S100 protein, and galanin. Multiple metastatic tumors were found in the kidneys, spleen, lungs, heart, and liver.

Fetal bile acid metabolism: analysis of urinary 3beta-monohydroxy-delta(5) bile acid in preterm infants

To elucidate the urinary concentration of total bile acids after birth and the profile of the usual and unusual urinary bile acids, especially 3beta-hydroxy-5-cholen-24-oic acid (Delta(5)-3beta-ol), we measured the concentrations of 13 bile acids in the urine from preterm infants vs. full-term controls by gas chromatography-mass spectrometry. The urinary concentration of total bile acids in early preterm infants below 32 weeks of gestational age significantly exceeded that of the late preterm and full-term infants (p < 0.0005). The major urinary bile acids in early preterm infants were cholic acid, 1beta,3alpha,7alpha,12alpha-tetrahydroxy-5beta-cholan-24-oic acid and Delta(5)-3beta-ol. In conclusion, the high urinary concentrations of total bile acids in preterm infants may be due to an overproduction, or more likely to a low hepatic bile acid clearance. An alternative fetal pathway, the acidic pathway, may be a major route of bile acid biosynthesis in preterm infants.

Metabolic significance and expression of Caenorhabditis elegans type II 3-oxoacyl-CoA thiolase

The authors cloned the cDNA of the nematode Caenorhabditis elegans encoding a 44-kDa protein (P-44), which is similar to sterol carrier protein x (SCPx). Genomic DNA data and Northern blot analysis excluded the possibility of P-44 forming SCPx-like fusion protein. P-44 is required in the formation of bile acid in vitro from CoA esters of their enoyl-form intermediate in the presence of D-3-hydroxyacyl-CoA dehydratase/D-3-dehydrogenase bifunctional protein. Also, rat SCPx converts 24-hydroxy-form intermediate to bile acid under similar conditions. From this and other evidence, P-44 and SCPx were categorized as type II thiolase. The mRNA encoding P-44 was detected in every developmental stage of C. elegans: egg, larval stages, and adult. P-44, therefore, seems essential for the normal functioning of this organism.

Advanced glomerulosclerosis is reversible in nephrotic mice

Advanced glomerulosclerosis, a common hallmark of chronic renal diseases (CRD) is believed to be irreversible, and it is thought that glomerular hyperfiltration and hypertrophy may participate in its pathogenesis. We demonstrate here that glomerulosclerosis is "reversible" in an animal model. We used nephrotic ICGN (nep/nep) mice which showed a rapid progression of glomerulosclerosis, accompanied by histological findings for glomerular hyperfiltration. It is known that ureter ligation reduces glomerular filtration in ligated kidneys. When ureter ligation was applied to our model, glomerulosclerosis (characterized by myofibroblast hyperplasia and over-accumulated matrix protein) weakened in conjunction with suppressed glomerular hypertrophy. During this process, glomerular myofibroblasts showed apoptotic cell death after unilateral ureter ligation (UUO) treatment. Our results suggest that inhibition of glomerular filtration in sclerotic tufts may cause glomerular remodeling through the modulation of molecular and cellular sclerogenesis.

Synthesis of coenzyme A esters of 3alpha,7alpha,12alpha-trihydroxy- and 3alpha,7alpha-dihydroxy-24-oxo-5beta-cholestan-26-oic acids for the study of beta-oxidation in bile acid biosynthesis

3alpha,7alpha,12alpha-Trihydroxy- and 3alpha,7alpha-dihydroxy-24-oxo-5beta-cholestan-26-oyl CoAs were chemically synthesized by the conventional method for the study of side chain cleavage in bile acid biosynthesis. 3alpha,7alpha,12alpha-Triformyloxy- and 3alpha,7alpha-diformyloxy-5beta-cholan-24-als were initially subjected to the Reformatsky reaction with methyl alpha-bromopropionate, and the products were then converted into methyl 3alpha,7alpha,12alpha-triformyloxy- and 3alpha,7alpha-diformyloxy-24-oxo-5beta-cholestan-26-oates. Protection by acetalization of the 24-oxo-group of these methyl esters with ethylene glycol, followed by alkaline hydrolysis, gave 3alpha,7alpha,12alpha-trihydroxy- and 3alpha,7alpha-dihydroxy-24,24-ethylenedioxy-5beta-cholestan-26-oic acids. These acids were condensed with coenzyme A by a mixed anhydride method, and the resulting CoA esters were treated with 4M-hydrocholic acid to remove the protecting group to give 24-oxo-5beta-cholestanoic acid CoA esters. The chromatographic behaviors of these CoA esters were also investigated.

Immunohistochemical analysis of molecular events in tubulo-interstitial fibrosis in a mouse model of diffuse mesangial sclerosis (ICGN strain)

Diffuse mesangial sclerosis (DMS) is one of the hereditary glomerular diseases and histologically characterized by severe glomerulosclerosis and subsequent tubulo-interstitial fibrosis (TIF). In DMS patients, renal dysfunction correlates well with TIF, rather than with glomerular lesions. Thus, molecular mechanisms whereby TIF in DMS progresses should be addressed. Previously, we found that nephrotic ICGN mice manifest DMS-like lesions and develop renal dysfunction in accordance with onset of TIF. In the present study, we investigated fibrogenic events involved in the progression of TIF after DMS manifestation, using the DMS mouse model. Immunohistochemistry revealed that expression of transforming growth factor-beta (TGF-beta) was rare in the interstitial cells of the nephrotic mice at the early-stage of DMS, while the TGF-beta expression became evident in the late-stage DMS mice. Platelet-derived growth factor (PDGF) was mildly expressed in the distal tubules of the early-stage DMS mice, whereas the PDGF expression markedly increased at the late-stage of DMS. As a result, alpha-actin-positive myofibroblastic cells were found dominant in the interstitial spaces of the late-stage DMS mice. Finally, TIF became severe in accordance with the overexpressions of these molecules. Our results suggest that in our murine model: 1) persistent proteinuria leads to over-expression of TGF-beta and PDGF in non-glomerular areas; 2) these cytokines provoke interstitial myofibroblast accumulation; and 3) the myofibroblasts produce fibrotic matrix proteins in the interstitial spaces. This process may possibly contribute to the development of TIF in DMS patients.

Conjugation reactions catalyzed by bifunctional proteins related to beta-oxidation in bile acid biosynthesis

The conjugation reactions of hydration and dehydrogenation catalyzed by the dehydratase and dehydrogenase activities of D-3-hydroxyacyl-CoA dehydratase/D-3-hydroxyacyl-CoA dehydrogenase bifunctional protein (DBP) and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional protein (LBP) in the side chain degradation step of bile acid biosynthesis were investigated using chemically synthesized C27-bile acid CoA esters as substrates. The hydration catalyzed by DBP showed high diastereoselectivity for (24E)-3alpha,7alpha,12alpha-trihydroxy- and (24E)-3alpha,7alpha-dihydroxy-5beta-cholest-24-en-26-oyl CoA to give (24R,25R)-3alpha,7alpha,12alpha,24-tetrahydroxy- and (24R,25R)-3alpha,7alpha,24-trihydroxy-5beta-cholestan-26-oyl CoAs, respectively, and the dehydrogenation catalyzed by DBP also showed high stereospecificity for the above (24R,25R)-isomers to give 3alpha,7alpha,12alpha-trihydroxy- and 3alpha,7alpha-dihydroxy-24-oxo-5beta-cholestan-26-oyl CoAs, respectively. On the other hand, the dehydratase activity of LBP displayed a different diastereoselectivity producing the (24S,25S)-isomer, and dehydrogenase activity of LBP was stereospecific for the (24S,25R)-isomer to give the above 24-oxo-derivative. The hydration and dehydrogenation reactions catalyzed by DBP were effectively conjugated to convert (24E)-5beta-cholestenoyl CoA to 24-oxo-5beta-cholestanoyl CoA. However, the reactions catalyzed by LBP were not conjugated. These results indicate that DBP plays an important role in the biosynthesis of bile acid.

Factors predicting mortality in patients after myocardial infarction caused by left main coronary artery occlusion: significance of ST segment elevation in both aVR and aVL leads

Acute left main coronary artery obstruction is rare and most patients in this clinical setting die of sudden death or cardiogenic shock. During the past 8 years, we encountered 13 patients with acute myocardial infarction caused by total occlusion of the left main coronary artery (LMCA-AMI). Thus, we surveyed these patients, and attempted to elucidate helpful predictors related to the prognosis. Six of 13 patients with LMCA-AMI survived. Successful left coronary artery dilatation was achieved in all survivors (group S), and in 5 (71%) non-survivors (group non-S). The age was not different between the two groups. A past history of angina was confirmed in 83% of group S. while only in 29% of group non-S. Clinical findings such as time of onset of AMI, interval from the AMI onset to admission, elapsed period from the AMI onset to recanalization of LMCA and the value of CK on admission were not different between the two groups. However, cardiogenic shock occurred in only 1 patient (17%) in group S compared with 5 patients (71%) in group non-S. As emphasized in the literature, good collateral circulation to the left anterior descending artery was observed in 5 patients (83%) in group S, while not observed in group non-S. Electro cardiographically, ST elevation in the aVR lead was very characteristic. This finding was confirmed in 69% of the total patients. Noticeably, 5 out of 6 non-survivors (83%) showed ST elevation not only in leads aVR but also in the aVL lead. In addition to the absence of collateral circulation, this electrocardiographic finding, which obviously indicates the presence of extensive myocardial ischemia in the diseased heart, is a simple and important predictor suggesting a poor prognosis in LMCA-AMI patients.

Expression of alpha-smooth muscle actin and fibronectin in tubulointerstitial lesions of cats with chronic renal failure

OBJECTIVE

To examine renal expression of alpha-smooth muscle actin (alpha-SMA) and fibronectin in cats with tubulointerstitial nephritis (TIN) for use in predicting progression to renal fibrosis.

ANIMALS

19 cats with TIN and 9 cats without nephritis.

PROCEDURE

Serum creatinine and BUN concentrations were measured. Indices for glomerular extra-cellular matrix (ECM), tubular injury (TI), and fibronectin were determined in renal specimens to quantify the extent of injury and fibrotic lesions. Expression of alpha-SMA in renal tissue was immunohistochemically detected, and correlations were evaluated between the alpha-SMA index and other histologic and clinical variables.

RESULTS

The alpha-SMA index in tubulointerstitial areas (1.63 +/- 0.78) was significantly higher in cats with TIN, especially in the periglomerular and peritubular areas, than in cats without nephritis (0.20 +/- 0.14). The alpha-SMA index was significantly associated with the TI index (r2 = 0.70), fibronectin index (r2 = 0.95), BUN concentration (r = 0.64), and serum creatinine concentration () = 0.66). Of special interest was that interstitial alpha-SMA expression appeared evident in the kidneys at an early stage of TIN, prior to the onset of ECM deposition.

CONCLUSION AND CLINICAL RELEVANCE

Analysis of results of histologic and clinical examinations revealed that interstitial alpha-SMA expression may have clinical importance and may be a useful early histologic marker for development of chronic renal failure in cats. An immunohistochemical examination for fibrogenic molecules (such as alpha-SMA expression) may provide fundamental information on the pathogenesis of early-stage renal disease and aid clinical management of cats with chronic renal failure, including TIN.

Nephrotic mice (ICGN strain): a model of diffuse mesangial sclerosis in infantile nephrotic syndrome

The ICGN mouse strain is a unique model for naturally occurring nephrotic syndrome. In the present study, we examined the onset of the clinical manifestation of nephrotic syndrome and determined the sequence of intraglomerular events associated with progression of nephrotic conditions. Laboratory analysis revealed that homozygous (nep/nep) mice showed urinary albumin excretion during the suckling stage, rapidly leading to hypoalbuminemia accompanied by body growth failure. Renal pathology demonstrated that an initial intraglomerular event in the nephrotic mice was observed 3 weeks after birth in the form of mesangiolytic lesions, characterized by microaneurysm, platelet accumulation and capillary ballooning. In 6-week-old homozygous mice, mesangial sclerosis, characterized by mesangial expansion and glomerular hypertrophy, was observed in a diffuse fashion. Immunohistochemistry revealed that the glomerular cells in the 3-week-old homozygous suckling mice were positive for alpha-smooth muscle actin, suggesting a phenotypic change in the mesangial cells. Mesangial expansion, confirmed by the over-deposition of type I collagen, was evident until 6 weeks after weaning, while it was of interest that fibrogenic cytokines such as platelet-derived growth factor and transforming growth factor-beta were not detected in the sclerotic glomeruli throughout the observations. Furthermore, the nephrotic features were shown to be resistant to steroid therapy with a high dose of prednisolone. Our results suggest that diffuse mesangial sclerosis, a hereditary glomerular disease, may be genetically generated through early myofibroblast formation, which occurs and develops probably independently of up-regulation of these fibrogenic cytokines. In conclusion, the homozygous nephrotic mouse (ICGN strain) is believed to be a good model for investigating not only nephrotic conditions but also cellular and molecular pathogenesis of diffuse mesangial sclerosis in steroid-resistant infantile nephrotic syndrome.