Urinary podocytes in primary focal segmental glomerulosclerosis.

BACKGROUND/AIM: Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome. Although the pathogenesis is not known, recent studies suggest that FSGS may be a podocyte disease. The aim of this study was to look for podocyte injury in this disease, using measurements of urinary podocytes. METHODS: We examined the first morning urine of the day collected from 71 patients (45 men and 26 women, median age and range 11.2 and 3-29 years) diagnosed as having nephrotic syndrome. Freshly voided urine samples were examined by immunofluorescence labeling using monoclonal antibodies against human podocalyxin. Renal histological examinations were performed in 58 of the 71 patients: 28 had minimal-change disease, 20 had FSGS, and 10 had membranous nephropathy. RESULTS: Median and range of urinary podocytes measured were 0.2 and 0-40.8 cells/ml for 71 patients with nephrotic syndrome and 0 and 0-0.8 cells/ml for normal healthy control subjects (n = 200). Patients with FSGS had significantly higher levels of urinary podocytes (median and range 1.3 and 0-40.8 cells/ml) than those with minimal-change disease (median and range 0 and 0-6.9 cells/m; p = 0.003) or membranous nephropathy (median and range 0 and 0-1.4 cells/ml; p = 0.02). CONCLUSIONS: The urinary excretion of podocytes is significantly higher in patients with FSGS as compared with those having membranous nephropathy or minimal-change disease. These findings suggest that podocyte injury and loss in the urine may have an important role in the pathogenesis of FSGS.

FAT is a component of glomerular slit diaphragms.

BACKGROUND: Slit diaphragms are intercellular junctions of podocytes of the renal glomerulus. The molecular composition of slit diaphragms is still elusive. Slit diaphragms are characterized by the presence of a wide intercellular space. The morphological feature is shared by desmosomes and adherens junctions, which contain members of the cadherin superfamily. Thus, we have hypothesized that some components of slit diaphragms belong to the cadherin superfamily. Consequently, we have isolated cDNA encoding FAT from reverse-transcribed (RT) glomerular cDNA by homology polymerase chain reaction (PCR) using primers based on conserved sequences in cadherin molecules. FAT is a novel member of the cadherin superfamily with 34 tandem cadherin-like extracellular repeats, and it closely resembles the Drosophila tumor suppressor fat. METHODS: Expression of FAT was examined in glomeruli of the adult rat kidney by the ribonuclease protection assay and in situ hybridization. To localize the FAT protein in podocytes minutely, we prepared affinity-purified antibody against FAT by immunizing rabbits against an oligopeptide corresponding to the C-terminal 20 amino acids. RESULTS: Expression of FAT mRNA was detected in total RNA from glomeruli. In situ hybridization revealed significant signals in podocytes. Western blot analysis using solubilized glomeruli showed a single band, in which the molecular weight was more than 500 kD. Immunostaining of cultured epithelial cells from rat kidney (NRK52E) revealed FAT accumulation in cell-cell contact sites. In the glomerulus, FAT staining was observed distinctly along glomerular capillary walls. Double-label immunostaining using monoclonal antibody against slit diaphragms (mAb 5-1-6) showed identical localization of anti-FAT antibody and mAb 5-1-6. Furthermore, the double-label immunogold technique with ultrathin cryosections demonstrated that gold particles for FAT cytoplasmic domain were located at the base of slit diaphragms labeled by mAb 5-1-6 and that the cytoplasmic domain of FAT colocalized with ZO-1, a cytoplasmic component associated with slit diaphragms. CONCLUSION: The molecular structure of FAT and its colocalization with 5-1-6 antigen and ZO-1 indicate that FAT is a component of slit diaphragms.

Expression profile of extracellular matrix and its regulatory proteins during the process of interstitial fibrosis after anti-glomerular basement membrane antibody-induced glomerular sclerosis in Sprague-Dawley rats.

Anti-glomerular basement membrane (GBM) nephritis in Sprague-Dawley (SD) rats was characterized by development of marked glomerular sclerosis and tubulointerstitial fibrosis. To elucidate sequential change of the glomerular sclerosis and tubulointerstitial fibrosis, accumulation and mRNA expression of extracellular matrix (ECM) components and transforming growth factor (TGF)-beta were examined in the glomerulus and cortex during the disease course by histology, immunostaining and ribonuclease protection assay. Mild proliferative and degenerative lesions appeared in the glomeruli by day 15 after anti-GBM antibody binding to GBM and progressed to glomerular sclerotic lesion thereafter. Conversely, interstitial change was first recognized by infiltration of mononuclear cells after day 20, followed by marked accumulation of ECM and tubular degeneration. The interstitial fibrosis was induced without apparent binding of anti-GBM antibody to tubular basement membrane. Accumulation of fibronectin, collagen type I and type IV was noted in the interstitium by immunofluorescence microscopy in association with enhanced expression of mRNA for these ECM components and their regulatory molecules such as matrix metalloproteinase (MMP2), tissue inhibitor of metalloproteinase (TIMP)-1 and TGF-beta1 both in glomeruli and cortex. The glomerular expression of these mRNA increased apparently by day 15 and reached a plateau or a peak at day 20. The expression of the same mRNA increased gradually from day 15 to day 29 in the cortex. These observations show that interstitial fibrosis follows glomerular sclerosis after anti-GBM antibody injection in SD rats, suggesting that at least a part of the mechanism for ECM accumulation in the glomerulus and interstitium is essentially the same in terms of composition of ECM and expression of its regulatory molecules.

Origin of hyperplastic epithelial cells in idiopathic collapsing glomerulopathy.

AIMS: Glomerular epithelial cell hypertrophy and hyperplasia are listed as the primary criteria for the diagnosis of collapsing glomerulopathy (CG), a distinct variant of focal segmental glomerulosclerosis. However, the extent of podocyte phenotypic alterations that occur in CG, and the origin of the hyperplastic epithelial cells remain to be established. METHODS AND RESULTS: Renal biopsy materials from seven out of three patients with CG were studied by serial section analysis for immunohistochemistry and electron microscopy. Markers for podocytes (PHM5 and synaptopodin), parietal epithelial cells (PECs: cytokeratin) and macrophages (CD68) were used for the immunohistochemistry. Multiple ultrathin sections from a total of 15 glomeruli, including some from patients with CG, were examined by electron microscopy. Glomerular adhesions occurred in 71% of the serially sectioned glomeruli taken from patients with CG. Hyperplastic epithelial cells were immunonegative for podocyte markers and CD68, but invariably immunopositive for cytokeratin. Electron microscopy revealed that detachment of the podocytes from involved glomerular capillary walls was extensive. Many of the detached podocytes appeared to be necrotic and apoptotic. In contrast, junctional complexes of desmosomes and zonula adherens connected hyperplastic epithelial cells to each other. Cilia were also often observed. CONCLUSIONS: The results of our ultrastructural and immunohistochemical study suggest that the hyperplastic epithelial cells observed in cases of CG are derived from PECs. Our results raise the possibility that PECs play a general role in covering glomerular tufts from which the podocytes have disappeared.

Identification of renal podocytes in multiple species: higher vertebrates are vimentin positive/lower vertebrates are desmin positive.

We sought to characterize podocytes in the kidneys of numerous species from amphibians to mammals because of the pivotal function of these cells in renal diseases. For this purpose, intermediate filament (IF) proteins of podocytes were examined by immunofluorescence microscopy using antibodies against vimentin, cytokeratins, and desmin. These staining patterns were then compared to those of parietal cells of Bowman's capsule and tubular cells of the first portion of the proximal tubule from the same sources. As a result, podocytes from mammals (rat, rabbit, dog, cow, and human) and birds (chicken) showed intense vimentin staining without exception, but rarely staining for cytokeratins or desmin. Parietal cells from all these animals were highly heterogeneous with respect to cytokeratin or vimentin staining. Of the tubular cells, only those from humans and chickens were reactive and then only with anti-cytokeratin antibodies. In the reptiles (Chrysemys scripta elegans, Chinemys reeveri, Elaphe quadrivirgata, and Anolis carolinensis), podocytes and other epithelial cells were positive for cytokeratins. Vimentin staining differed among the species, but was not characteristic for podocytes. Anti-desmin antibody reacted strongly only with podocytes from Anolis. In amphibians (Rana catesbeiana and Xenopus laevis), anti-desmin antibody stained podocytes more intensely than any other cell. Cytokeratin and vimentin staining did not differentiate podocytes from the other cell types. These findings indicate that podocytes are characterized by intense vimentin staining in the higher vertebrates and by desmin staining in the lower vertebrates denoting potentially distinctive physiological functions of IF proteins in podocytes from each of these groups.

Expression and localization of aquaporins in rat gastrointestinal tract.

A family of water-selective channels, aquaporins (AQP), has been demonstrated in various organs and tissues. However, the localization and expression of the AQP family members in the gastrointestinal tract have not been entirely elucidated. This study aimed to demonstrate the expression and distribution of several types of the AQP family and to speculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1-5 and AQP8 was examined in various portions through the gastrointestinal tract. AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon, and their expression was relatively intense in the small intestine and colon. In contrast, AQP4 mRNA was selectively expressed in the stomach and small intestine and AQP8 mRNA in the jejunum and colon. Immunohistochemistry and in situ hybridization demonstrated cellular localization of these AQP in these portions. AQP1 was localized on endothelial cells of lymphatic vessels in the submucosa and lamina propria throughout the gastrointestinal tract. AQP3 was detected on the circumferential plasma membranes of stratified squamous epithelial cells in the esophagus and basolateral membranes of cardiac gland epithelia in the lower stomach and of surface columnar epithelia in the colon. However, AQP3 was not apparently detected in the small intestine. AQP4 was present on the basolateral membrane of the parietal cells in the lower stomach and selectively in the basolateral membranes of deep intestinal gland cells in the small intestine. AQP8 mRNA expression was demonstrated in the absorptive columnar epithelial cells of the jejunum and colon by in situ hybridization. These findings may indicate that water crosses the epithelial layer through these water channels, suggesting a possible role of the transcellular route for water intake or outlet in the gastrointestinal tract.

Acute in vivo effects of ACTH by exo utero microinjection on differentiation, steroidogenesis and proliferation of fetal mouse adrenocytes.

Mouse embryos on embryonic day (E)13 or 14 were treated with ACTH1-24 by exo utero microinjection and the adrenal was examined after 16 and 32 h. Light microscopic morphometry showed that the ACTH treatment increased cell size and decreased cell density of the adrenocortical cells. Bromodeoxyuridine-labeling index did not alter significantly after the ACTH treatment. By immunohistochemistry, both number of cells expressing 11beta-hydroxylase and the staining intensity increased in the ACTH-treated glands compared to controls whereas expression of aldosterone synthase was detectable in neither the treated nor control groups. Ultrastructurally, the adrenocytes of the inner cortical zone of the ACTH-treated glands were characterized by strikingly increased content of the smooth endoplasmic reticulum, increased mitochondria with more vesicular cristae, lipid droplets with a much higher electron density along with the distribution altered from that in controls. All of the significant differences between the ACTH-treated and control glands occurred at 16 h but not at the 32 h interval. The present results indicated that the mouse fetal adrenocytes are already sensitive to ACTH during early period (E13 and 14) of their functional differentiation. In vivo acute treatment of ACTH stimulates cell-size, increase of fetal adrenocytes but not proliferation, and may directly or indirectly regulate multiple steps of the steroidogenic process of the fetal mouse adrenal.

Localization and expression of AQP5 in cornea, serous salivary glands, and pulmonary epithelial cells.

Aquaporin (AQP) 5 gene was recently isolated from salivary gland and identified as a member of the AQP family. The mRNA expression and localization have been examined in several organs. The present study was focused on elucidation of AQP5 expression and localization in the eye, salivary gland, and lung in rat. RNase protection assay confirmed intense expression of AQP5 mRNA in these organs but negligible expression in other organs. To examine the mRNA expression sites in the eye, several portions were microdissected for total RNA isolation. AQP5 mRNA was enriched in cornea but not in other portions (retina, lens, iris/ciliary body, conjunctiva, or sclera). AQP5 was selectively localized on the surface of corneal epithelium in the eye by immunohistochemistry and immunoelectron microscopy using an affinity-purified anti-AQP5 antibody. AQP5 was also localized on apical membranes of acinar cells in the lacrimal gland and on the microvilli protruding into intracellular secretory canaliculi of the serous salivary gland. In the lung, apical membranes of type I pulmonary epithelial cells were also immunostained with the antibody. These findings suggest a role of AQP5 in water transport to prevent dehydration or to secrete watery products in these tissues.

Long-term observation of glomerulonephritis induced by multiple injections with anti-Thy-1 antibody in rats.

Multiple injections with a mouse monoclonal anti-rat Thy-1 antibody (five times, at weekly intervals) induced marked glomerular sclerotic lesions which are characterized by adhesion of glomerular capillaries to Bowman's capsule and persistent proteinuria in rats. Abnormal production of type I collagen and increased accumulation of type IV collagen and fibronectin were observed in these glomeruli. The glomerular expression of mRNA for these matrix components and transforming growth factor-beta1 (TGF-beta1) were markedly increased at 4 days after the last injections with anti-Thy-1 antibody, but decreased to below the levels of control rats at 5 weeks. This may be down-regulation of mRNA in mesangial cells. The glomerular sclerotic lesions were not progressive but the process of glomerular healing seemed to be retarded. The proteinuria and the glomerular adhesion were irreversible.

Importance of type IV collagen, laminin, and heparan sulfate proteoglycan in the regulation of labyrinthine fluid in the rat cochlear duct.

The distribution of major components of the basement membrane, such as type IV collagen, laminin, and heparan sulfate proteoglycan (HSPG), was investigated in the rat cochlear duct. Immunofluorescence demonstrated that type IV collagen, laminin and HSPG were distributed along capillaries in the cochlear duct, including the stria vascularis, spiral ligament, spiral prominence and spiral limbus. Additionally, type IV collagen, laminin and HSPG were found to be distributed from the basement membrane of Reissner's membrane to that of the spiral prominence in a linear pattern. The scala media was surrounded by these basement membrane components, demarcating endolymph from perilymph, along epithelial cells except at the stria vascularis. These findings suggest that type IV collagen, laminin and HSPG create the anatomical separation between endolymph and perilymph, thus indicating that they may be involved in the regulation of fluid transport between the endolymph and perilymph.

Involvement of R-cadherin in the early stage of glomerulogenesis.

The earliest commitment to the formation of glomeruli is recognizable in S-shaped bodies. Although cell-cell adhesion seems likely to play a crucial role in this process, how glomerular epithelial cells segregate from the other parts of the nephron is unknown. In this study, immunofluorescence microscopy and monoclonal antibodies specific for mouse R-, E-, P- and N-cadherins were used to examine which of these adhesion molecules are involved in glomerulogenesis of the mouse kidney. Weak R-cadherin staining was first found in the vesicle stage, becoming restricted to glomerular visceral epithelial cells (VEC) during the S-shaped body stage. The intensity of this staining became stronger in the capillary loop stage, whereas parietal epithelial cells (PEC) and tubular cells did not stain. In the maturing stage, VEC gradually lost their staining for R-cadherin. E-cadherin was detected in ureteric buds and the upper limb of S-shaped bodies. From the capillary loop to the maturing stage, anti-E-cadherin stained epithelial cells in all tubule segments, but no label was seen in VEC or PEC. P-cadherin was also stained in the ureteric buds and in the upper limb of S-shaped bodies. N-Cadherin was weakly stained in cells at the vesicle stage, but thereafter staining of N-cadherin was not detected at any stage of glomerular formation. Immunoelectron microscopy of differentiating VEC was performed using antibodies specific to alpha-catenin, which is associated with cadherin. Subsequently, immunogold particles identifying alpha-catenin were localized on junctions between primary processes of VEC. These findings indicate that R-cadherin is uniquely expressed in differentiating VEC, suggesting an important role in the early stages of glomerulogenesis.

Thyroid hormone regulates expression of shaker-related potassium channel mRNA in rat heart.

Effects of thyroid hormones on cardiac function or rhythm have been known; however, the mechanism is still unclear. In the present study examined were effects of triiodethyronine (T3) on voltage-gated potassium channel gene expression in rat heart since the potassium channels were presumed to modulate cardiac functions. The mRNA expression of five voltage-gated potassium channel gene alpha subunits (Kv1.2, Kv1.4, Kv1.5, Kv2.1, and Kv4.2) in heart was examined by ribonuclease protection assay in rats which were treated with T3 or propylthyouracil (PTU). All these genes except Kv1.4 mRNA were apparently expressed in the normal rat heart ventricle. Kv1.2 mRNA expression in ventricle was markedly suppressed by T3-treatment and enhanced by PTU-treatment. Interestingly, upregulation of Kv1.4 mRNA expression and downregulation of Kv1.5 mRNA expression were concomitantly induced in the ventricle by the PTU-treatment. In addition, the downregulation of the ventricular Kv1.5 mRNA expression induced by PTU was restored by T3 replacement. No changes of Kv2.1 and Kv4.2 mRNA expression were observed in the ventricles by the T3- or PTU-treatment. In heart atrium the same findings were observed. Kv1.4 mRNA expression, which was detectable in control rat atrium, also decreased significantly by T3-treatment. In contrast, no changes of Kv1.2, Kv1.4, and Kv1.5 mRNA expression in rat brains were induced by T3-treatment. These findings suggest that thyroid hormone specifically influences mRNA expression of Shaker-related potassium channel genes in rat hearts through a common T3 receptor-mediated regulation at a transcriptional level.

Immunohistochemical and urinary markers of podocyte injury.

Renal podocytes play an important role in glomerular filtration. We estimated podocyte injury by light microscopic examination of kidney specimens or by urinary excretion of substances related to podocytes. Fresh kidney sections from 69 patients and urinary sediments from 84 patients with various renal diseases were examined immunohistochemically using fluorescent labelling. Four kinds of monoclonal antibodies which recognize podocytes were used: (1) anti-podocalyxin (anti-PCX) antibody, (2) anti-C3b receptor (anti-C3bR) antibody, (3) anti-podocyte protein, 44 kilodalton, (anti-pp44) antibody, and (4) anti-alpha 3 integrin (anti-Int alpha3) antibody. Labelling of kidney sections by anti-C3bR (k-C3bR) was reduced in cases of severe glomerular injury, although there were no changes in k-PCX, k-pp44, or k-Int alpha3 labelling. PCX labelling of urinary sediments (u-PCX) was detected in nearly all cases of glomerulonephritis, u-C3bR was seen in some cases of glomerular injury, u-Int alpha3 was seen in only a small number of cases of severe glomerular injury, and u-pp44 was not detected in any urinary samples. u-PCX, u-C3bR, u-Int alpha3, and k-C3bR correlated with the degree of pathological change, the degree of proteinuria and hematuria. These results suggest that immunostaining kidney sections with anti-C3bR antibody and urinary sediments with anti-PCX, anti-C3bR, and anti-Int alpha3 antibodies might be useful in detecting podocyte injury.

Expression and localization of cyclooxygenase isoforms and cytosolic phospholipase A2 in anti-Thy-1 glomerulonephritis.

Glomerular expression of the major rate-limiting enzymes for prostanoid synthesis, cyclooxygenase isoforms (COX-1 and COX-2) and cytosolic phospholipase A2 (cPLA2), was investigated in anti-Thy-1 nephritis in rats. Ribonuclease protection assay demonstrated minimal COX-1 mRNA expression in glomeruli of control rat kidneys and a gradual increase of expression from day 1 to day 10 after administration of monoclonal anti-rat Thy-1 antibody. On the other hand, COX-2 mRNA expression, also minimal in the normal glomeruli, was enhanced in a biphasic pattern with two peaks at 1 h and day 10. Expression of cPLA2 mRNA, which was undetectable in normal glomeruli, was induced on day 1 and increased gradually in a pattern similar to that of COX-1 mRNA expression. Immunofluorescence microscopy, using antibodies against COX isoforms, showed that both COX-1 and COX-2 were negligible or faintly detectable in the glomeruli of control rat kidneys. In contrast, the immunofluorescence for COX-1 was intensified on days 4 and 10 along the glomerular capillary walls probably in glomerular epithelial and/or endothelial cells, whereas COX-2 staining was exclusively enhanced in the glomerular epithelial cells at 1 h and day 10 during the course of anti-Thy-1 nephritis. These findings indicate that prostanoids generated through induction of COX-1, COX-2, and cPLA2 are implicated in the mediation of the mesangial cell injury model. In particular, the upregulation of COX-2 expression in glomerular epithelial cells in the selective mesangial cell injury model suggests an intercellular interaction between mesangial cells, and glomerular epithelial cells.

Urinary excretion of podocytes reflects disease activity in children with glomerulonephritis.

The significance of the presence of podocytes in the urine was studied in various renal diseases in children. The podocytes were detected by immunofluorescence using monoclonal antibodies against the podocalyxin that is present on the surface of podocytes which serves as a glycocalyx. They were scored according to the numbers per partitioned area on cytospun urine sediments. Urine podocytes were absent in normal control, nonglomerular diseases such as urinary tract infection and nonglomerular hematuria, and glomerular, non-inflammatory diseases such as minimal change nephrotic syndrome and membranous nephropathy. Conversely, the excretion of podocytes in the urine were detected in various glomerular, inflammatory diseases. A significantly higher level of the podocyte score was found in the acute state of glomerular diseases which was defined as within 6 months after disease onset. Positive correlations were obtained between the presence of urinary podocytes and the histological features of active extracapillary changes and mesangial proliferation. Urinary podocytes were examined monthly for 12 months in 7 cases with IgA nephropathy and 2 cases with Henoch-Schönlein purpura nephritis, and a consistently higher urinary podocyte score was observed in the patients with histological progression. The scoring of urinary podocytes was found to be useful clinically, as a diagnostic tool for glomerular or nonglomerular diseases, inflammatory or noninflammatory diseases, a marker for the estimation of the severity of active glomerular injury and also as a predictor of disease progression.

Molecular cloning of a new aquaporin from rat pancreas and liver.

A new water channel (aquaporin-8, gene symbol AQP8) was isolated from rat pancreas and liver by homology cloning. Ribonuclease protection assay showed intense expression of the gene in pancreas and liver, less intense in colon and salivary gland, and negligible in other organs. The full-length cDNA was obtained by ligation of approximately 1.4-kilobase (kb) cDNA isolated from the rat liver cDNA library to approximately 0.5 kb of the 5'-end fragment obtained by the rapid amplification of cDNA ends method. A major transcript of approximately 1.45 kb was demonstrated in liver and colon by Northern blot analysis. Expression of the cRNA in Xenopus oocytes markedly enhanced osmotic water permeability in a mercury-sensitive manner, indicating a water channel function of this molecule. The open reading frame encoded a 263-amino acid protein with a predicted molecular size of 28 kDa. Hydropathy analysis represented six membrane-spanning domains and five connecting loops containing two sites of NPA motif as preserved in other aquaporins. Unlike other mammalian aquaporins, AQP8 has an unusual structure with a long N terminus and a short C terminus, which are found in plant aquaporin, gamma-tonoplast intrinsic protein. By in situ hybridization, AQP8 mRNA expression was assumed in hepatocytes, acinal cells of pancreas and salivary gland, and absorptive colonic epithelial cells. The physiological role(s) of AQP8 remain to be elucidated.

Suppression of anti-glomerular basement membrane nephritis by administration of anti-monocyte chemoattractant protein-1 antibody in WKY rats.

Anti-glomerular basement membrane (GBM) nephritis in WKY rats is characterized by an accumulation of CD8-positive lymphocytes (CD8+ lym) and monocytes/macrophages (Mo/M psi) in the glomeruli and crescent formation. In the study presented here, the involvement of a chemokine for Mo/M psi, monocyte chemoattractant protein-1 (MCP-1), was examined in this model. An intense induction of mRNA for MCP-1 in the glomeruli and a suppressive effect of anti-MCP-1 antibody administration on the glomerular Mo/M psi accumulation and proteinuria were found. MCP-1 mRNA was expressed intensely in the glomeruli 4 d after the anti-GBM antibody injection. When MCP-1 was neutralized with anti-MCP-1 antibody administration, the number of Mo/M psi infiltrating in the glomeruli decreased by 34.7% (19.6 +/- 7.1 versus 30.0 +/- 6.0 per glomerular cross-section, P < 0.01) and proteinuria by 66.2% (15.6 +/- 9.3 versus 46.1 +/- 15.1 mg/d, P < 0.01) at day 4. In contrast, the number of CD8+ lym accumulating in the glomeruli was not affected significantly (6.6 +/- 2.7 versus 6.0 +/- 3.0 per glomerular cross-section, P > 0.05). However, the treatment with the anti-MCP-1 antibody did not reduce Mo/M psi infiltration, urinary protein excretion, and crescent formation at day 8. These data suggest that MCP-1 plays a role in the glomerular accumulation of Mo/M psi, and that the infiltrating Mo/M psi cause glomerular injury and increased excretion of protein in the urine.

Juxtaglomerular cell tumor of the kidney: report of a non-functioning variant.

A case of a juxtaglomerular cell tumor (JCT) in a 46-year-old man is reported. The tumor, 2.4 cm at its greatest dimension, was incidentally detected by ultrasonography. Although histological, immunohistochemical, and electron microscopic examinations revealed typical features of a JCT, the patient had no history of hypertension or hypokalemia. This is the first report of a non-functioning JCT in the literature.

Crucial role of CD8-positive lymphocytes in glomerular expression of ICAM-1 and cytokines in crescentic glomerulonephritis of WKY rats.

CD8-positive lymphocytes (CD8+ lym) and ICAM-1/LFA-1 interaction have been implicated in the glomerular accumulation of monocytes/macrophages (Mo/Mphi) and crescent formation in antiglomerular basement membrane (anti-GBM) glomerulonephritis of WKY rats. In the present study, the role of CD8+ lym in the expression of ICAM-1 and inflammatory cytokines as well as in the accumulation of Mo/Mphi in the glomeruli was examined by RNase protection assay and immunofluorescence microscopy. ICAM-1 expression was apparent at 1 h and markedly enhanced at day 3 in glomeruli after an anti-GBM Ab injection in parallel with glomerular accumulation of Mo/Mphi. Expression of mRNA for IL-1beta, TNF-alpha, and IFN-gamma, known to enhance ICAM-1 expression, and MIP-1alpha, MIP-1beta, and MCP-1, known to activate leukocyte integrins or to act as chemokines, were also induced in the glomeruli at a mRNA level in a profile similar to that of ICAM-1 expression. By depleting the CD8+ lym in the circulation, the increased glomerular expression of ICAM-1 and the cytokines, except IL-1beta, and the Mo/Mphi accumulation were suppressed, indicating a crucial role of CD8+ lym in the accumulation of Mo/Mphi through stimulation of ICAM-1 and induction of cytokines.