Contractile cells of the kidney in primary glomerular disorders: an immunohistochemical study using an anti-alpha-smooth muscle actin monoclonal antibody

Mesangial cells of the renal glomerulus are thought to have contractile properties, resembling those of smooth muscle cells. Since actin synthesis in mesangial cells is increased in selected animal models of glomerulonephritis, we evaluated the expression of alpha-smooth muscle actin (ASMA), the principal actin isoform found in smooth muscle cells, in biopsy specimens from patients with primary glomerular disorders and in control tissues. Normal glomeruli and glomeruli in acute tubulointerstitial disorders showed few or no ASMA-positive cells in the glomeruli. In contrast, ASMA expression in mesangial cells was increased in minimal change disease, focal segmental glomerulosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, and immunoglobulin A nephropathy. In membranoproliferative glomerulonephritis and cryoglobulinemic glomerulonephritis both mesangial and capillary loop ASMA-positive cells were observed with a segmental distribution. In addition, ASMA-positive interstitial cells were seen in many biopsy specimens and often were increased in number in biopsy specimens showing early interstitial fibrosis and tubular atrophy. We conclude that ASMA synthesis in mesangial cells is upregulated in a variety of glomerular disorders, frequently associated with increased cell proliferation and mesangial matrix production. This phenotypic change may be an indicator of mesangial cell activation after injury and may have important pathophysiologic consequences.     

Design and validation of a new image analysis method for automatic quantification of interstitial fibrosis and glomerular morphometry

Interstitial fibrosis and morphologic changes in kidney glomeruli, the structural effects of many diseases, lead to significant pathologic alterations. A reliable and objective method to accurately quantify the extent of interstitial fibrosis and the degree of alteration in glomerular morphology is needed for both clinical practice and experimental work. The morphometric methods of quantification described to date are time-consuming and require trained personnel. This article describes the design and validation of an image analysis-based application (Fibrosis HR) for automatically and rapidly quantifying interstitial fibrosis and glomerular morphology in the same tissue section stained with Sirius red. The image processing algorithms described herein automatically segment interstitial fibrosis and mesangial matrix using automatic thresholding and morphologic filtering. The glomerular region is extracted by a simple interactive step and an automatic mathematical morphology algorithm, whereas the glomerular tuft is automatically segmented with automatic thresholding and a sequence of Boolean and mathematical morphology operations. All extracted areas are automatically quantified in absolute (microm2) and relative (%) values. For validation of this method, interstitial fibrosis, mesangial matrix, and glomerular and glomerular tuft areas were manually segmented and their quantifications statistically compared with those obtained automatically. Statistical analyses showed significant intra- and interoperator variability in manual segmentation of interstitial fibrosis, mesangial matrix, and glomerular tuft areas. Automatic quantifications of the same areas did not differ significantly from their mean manual evaluations. There was no significant intra- or interoperator variability in the interactive identification of the glomerular region. In conclusion, Fibrosis HR produces robust, fully reproducible, accurate, objective, and reliable quantifications, which facilitate the evaluation of in vivo experimental models of renal interstitial and glomerular pathologies and improve the accuracy of clinicopathologic analyses of renal diseases in human biopsies.     

A case of sporadic acute type A hepatitis associated with acute renal failure

We report a case of sporadic acute type A hepatitis associated with acute renal failure, due to mesangioproliferative glomerulonephritis and interstitial nephritis. A 42 year-old-man was admitted to Mitsui Memorial Hospital because of jaundice and oliguria with fever in February, 1989. His serum creatinine was 12.2 mg/dl, BUN 87 mg/dl, GOT 57 U/l and GPT 358 U/l. The serum IgM antibody to hepatitis A virus was positive, which indicated recent infection with hepatitis A virus. Hemodialysis and steroidal therapy were started, and the patient's acute renal failure and liver dysfunction ameliorated within one month. Light microscopic examinations showed an increased number of mesangial cells and an increased amount of mesangial matrix, and also showed inflammatory cell invasion in the interstitium. Electron microscopic examinations showed proliferation of mesangial cells and matrix, and a dense deposit along the basement membrane. On immunofluoresent studies, fine granular deposits of IgA and Clq were observed in the mesangium.     

Influence of clinical and ventilatory parameters on morphology of bronchopulmonary dysplasia

Our aim was to assess multiple factors which contribute to bronchopulmonary dysplasia (BPD) in prematurely born neonates. Specific morphologic features might relate to cumulative oxygen dose, barotrauma, prematurity, infection, and persistent ductus arteriosus (PDA). Seventy-two patients dying from BPD as defined by the histopathologic criteria of Stocker were analyzed retrospectively. Median (range) gestational age was 28 (25-35) weeks, and median survival was 16 (5-386) days. The infants were ventilated for 15 (15-149) days with a mean inspired oxygen fraction (FiO2) of 0.78. The cumulative oxygen dose and mean airway pressures were determined. The presence of neonatal infection, PDA, and interstitial lung emphysema (ILE) was assessed. Baseline lung disease was estimated as proposed by Palta. At autopsy, the degree of hyaline membranes, epithelial cell necrosis, emphysema, atelectasis, interstitial cell proliferation, and lung fibrosis was scored semiquantitatively (0 to 3+). The influence of neonatal infection, PDA, gestational age, survival, oxygen dose, or barotrauma on morphological findings was examined by multivariate analysis. We found "acute" BPD in 22, "reparative" in 34 and long-standing-"healed" in 16 cases. ILE within the first week was associated with interstitial cell proliferation and lung fibrosis in infants surviving more than 28 days. Initial barotrauma contributes to lung fibrosis in infants with BPD.     

A comparison of ultrastructural changes on endomyocardial biopsy specimens obtained from patients with diabetes mellitus with and without hypertension

The pathogenesis of diabetic cardiomyopathy is unknown. The synergistic, or enhanced, effect of hypertension on pathological changes in the heart of diabetic patients has been highly suspected. The purpose of this study was to evaluate the myocardial changes related to diabetes mellitus with and without hypertension, using biopsy specimens. We examined the ultrastructural changes in biopsy specimens of the endomyocardium obtained from 25 patients. They were divided into four groups: controls without hypertension or diabetes mellitus (n = 6), and patient with hypertension (n = 3), diabetes mellitus (n = 8), and diabetes with hypertension (n = 8). The diabetic patients showed nearly normal or mildly depressed systolic left ventricular function. Ultrastructural pictures were analyzed for thickening of the capillary basement membrane, presence of toluidine blue-positive materials (i.e., materials showing metachromasia) in the myocytes, size of myocytes, and interstitial fibrosis. The thickening of the capillary basement membrane, the accumulation of toluidine blue-positive materials, and interstitial fibrosis were all significantly greater in the patients with diabetes mellitus compared to the control subjects. The myocytes tended to be small (cell atrophy) in the diabetes group. Although these pathological changes in the heart were characteristic of diabetic patients, irrespective of the presence or absence of hypertension, the presence of hypertension increased the pathological changes of myocardial cells as well as abnormality in the capillary vessels in patients with diabetes mellitus. Alterations in the myocardial cells and capillaries, caused by diabetes mellitus, may lead to myocardial cell injury and interstitial fibrosis and, ultimately, to ventricular systolic and diastolic dysfunction, especially when the diabetes is accompanied by hypertension.     

Mental health in action

Twenty-nine patients with insulin-dependent diabetes mellitus with similarly manifest renal involvement were examined to elucidate the role of dyslipidemia in diabetic nephropathy progress. Clinico-laboratory parameters (urinary albumin excretion, blood serum levels of total cholesterol, triglycerides, low, very low, and high density lipoprotein cholesterol) and morphologic changes in renal tissue biopsy specimens were analyzed. An increment of the number of large lipid incorporations was observed in various cells of renal glomeruli and interstitium, as well as a high prevalence of low density lipoprotein deposition in glomerular basal membranes and canaliculi as the renal process augmented in severity. Since lipids accumulating in glomerular structures may stimulate mesangial cell proliferation and mesangial matrix hyperproduction, the authors believe that dyslipidemia in diabetes mellitus may be conducive to a more rapid progress of renal disease.     

Three-dimensional triple-quantum-filtered 23Na imaging of the dog head in vivo

Uninephrectomized rats with diet-induced hypercholesterolemia develop interstitial inflammation and fibrosis after 8 to 12 weeks. Fibrosis has been associated with the accumulation of lipid peroxidation products within the tubulointerstitium, along with increased renal mRNA levels for transforming growth factor beta-1 (TCF-beta 1), some matrix proteins, and the tissue inhibitor of metalloproteinases (TIMP-1). However, mRNA levels for urokinase-type plasminogen activator (uPA) have been found to be decreased. The purpose of the present study was to determine whether antioxidant therapy could attenuate interstitial fibrosis in hypercholesterolemic rats and to determine changes in the pattern of renal gene expression induced by antioxidant therapy. Three groups of uninephrectomized rats were studied after 12 weeks of feeding standard rat chow, an atherogenic diet (standard chow plus 4% cholesterol/1% cholic acid), or an atherogenic diet supplemented with high doses of the antioxidants probucol and vitamin E. Rats fed the atherogenic diet developed hypercholesterolemia and a 56% increase in total kidney collagen compared with rats fed standard chow. In comparison, the hypercholesterolemic rats treated with antioxidants had normal levels of renal lipid peroxidation products and a normal kidney collagen content. In contrast, there were no significant differences in urinary albumin excretion rates or the number of interstitial macrophages between the two hypercholesterolemic groups. Compared with the untreated hypercholesterolemic group, antioxidant therapy induced significant reductions in renal mRNA levels for procollagen III (to 60% of untreated levels), collagen IV (60%), and TIMP-1 (20%), while uPA levels were significantly increased (to 210%). Paradoxically, antioxidant therapy was associated with a significant increase in renal TGF-beta 1 mRNA levels (to 150%), although TGF-beta 1 protein expression shifted from interstitial to tubular epithelial cells in predominance. The results of the present study demonstrate the efficiency of antioxidant therapy in preventing renal interstitial fibrosis in hypercholesterolemic rats with a single kidney. Based on changes in renal gene expression at the mRNA level, impaired matrix protein synthesis and increased intrarenal activity of the metalloproteinases and uPA/plasmin may play a role in the attenuation of fibrosis.     

Expression of TGF-beta 1, PDGF and IGF-1 mRNA in lung of bleomycin-A5-induced pulmonary fibrosis in rats

OBJECTIVE: To investigate the influence of alveolar macrophages (AMs), fibroblasts and interstitial cells on development of lung fibrosis, and the interactions among TGF-beta 1 PDGF and IGF-1 and these cytokines-effects on lung fibrosis. MATERIAL AND METHODS: Expressions of TGF-beta 1, PDGF and IGF-1 mRNA in the lung cells and lung tissues in different stages of Bleomycin-A5-induced pulmonary fibrosis in rats were studied through Northern hybridization. RESULTS: The expressions of TGF-beta 1 and PDGF mRNA reached their peaks in AMs of pulmonary fibrosis in rats on the 7th day after Bleomycin-A5 instillation. It was similar with that in the lung tissues. IGF-1 mRNA remained relatively stable in AMs during the course. PDGF and IGF-1 mRNA increased gradually in fibroblasts, and reached the highest expressions in the interstitial cells. There was almost no TGF-beta 1 mRNA expression in all groups of fibroblasts. CONCLUSIONS: AMs are the main sources of TGF-beta 1 and PDGF in the lung tissues with fibrosis induced by Bleomycin-A5 AMs are activated in the first weekend and secrete TGF-beta 1 and PDGF to promote fibroblasts proliferation and fibrosis. As fibrosis developed, fibroblasts have established PDGF and IGF-1 autocrine and these three cytokines paracrine nets combined with the interstitial cells to promote lung fibrosis.     

Renal disease in an adult patient with type I glycogen storage disease

A 26-year-old Chinese male patient with type I glycogen storage disease presented with chronic renal disease, proteinuria, and urolithiasis. On renal biopsy, focal glomerular sclerosis, increased mesangial matrix and cellularity, interstitial fibrosis, tubular atrophy, and prominent arteriosclerosis were observed. Immunofluorescence microscopy revealed Ig A deposits predominantly in the glomerular mesangium. The possible mechanisms of renal involvement in glycogen storage disease are briefly discussed.     

Tubular epithelial-myofibroblast transdifferentiation in progressive tubulointerstitial fibrosis in 5/6 nephrectomized rats

BACKGROUND: Tubulointerstitial fibrosis is the final common pathway to end-stage renal failure. The present study investigated the potential role of tubular epithelial cells (TEC) in progressive fibrosis in the rat remnant kidney model. METHODS: Rats underwent 5/6 nephrectomy or a sham operation (control), and groups of six animals were killed at weeks 1, 3, 5, 9, 13, 17 and 21. RESULTS: Immunohistochemistry staining and in situ hybridization at week 3 after nephrectomy demonstrated de novo expression of alpha-smooth muscle actin (alpha-SMA)--a marker of smooth muscle cells and myofibroblasts--by TEC that was invariably associated with disruption of the tubular basement membrane (TBM). This phenotypic evidence of tubular epithelial-myofibroblast transdifferentiation was supported by ultrastructural studies identifying the presence of characteristic actin microfilaments and dense bodies within TEC with a transformed morphology. In the late stage of this apparent tubular epithelial-myofibroblast transdifferentiation, TEC lost apical-basal polarity and tight junctions, became elongated, detached from the TBM, separated from neighboring cells and appeared to migrate into the peritubular interstitium through the damaged basement membrane. Indeed, focal peritubular accumulation of alpha-SMA+ myofibroblasts and local tubulointerstitial fibrosis was closely associated with alpha-SMA+ tubules, suggesting a tubular epithelial origin for some of these cells. Quantitative analysis found a significant correlation between the number of alpha-SMA+ TEC and the accumulation of interstitial alpha-SMA+ myofibroblasts and the severity of tubulointerstitial fibrosis (both P < 0.001). CONCLUSIONS: This study provides phenotypic and morphological evidence to support the hypothesis that TEC are pro-fibrogenitor cells capable of tubular epithelial-myofibroblast transdifferentiation in progressive renal fibrosis. In addition, we postulate that disruption of the TBM, which facilitates epithelial cell contact with the interstitial matrix, promotes this process of transdifferentiation.     

Morphology of ischemic acute renal failure, normal function, and cyclosporine toxicity in cyclosporine-treated renal allograft recipients

To characterize morphologic changes in the early post-transplant period in cyclosporine-treated renal allograft recipients, we examined biopsies from three groups of cyclosporine-treated patients: normal function (N = 9), ischemic acute renal failure or "acute tubular necrosis" (N = 12), and cyclosporine toxicity (N = 7). Groups were compared with each other and with previously studied groups of azathioprine-treated patients and native kidney patients. The interstitial infiltrate commonly observed in normally functioning azathioprine-treated grafts was not observed in normally functioning cyclosporine-treated grafts, but two of nine such grafts had a significant venulitis, a change also seen in three of the patients with cyclosporine nephrotoxicity. "Acute tubular necrosis" (ATN) in cyclosporine-treated graft recipients was characterized by focal necrosis of complete tubular cross sections, a finding normally rare in other types of ATN, and by shedding into the tubular lumen of tubular cells with non-pyknotic nuclei, a finding supporting our previous observation of detachment of viable tubular cells in ATN but not in the normal kidney. Hyaline arteriolar thickening was the only morphologic finding on biopsy which distinguished patients with cyclosporine nephrotoxicity from other groups. In summary, the morphologic changes observed in cyclosporine-treated renal allograft recipients with ATN or normal function are quite different from those observed in azathioprine-treated patients. Cyclosporine appears to enhance the tubular injury observed in ATN. Hyaline arteriolar thickening is the main distinguishing feature of cyclosporine nephrotoxicity.     

Localization of matrix metalloproteinases-1, -2, and -9 and tissue inhibitor of metalloproteinase-2 in interstitial lung diseases

In interstitial lung diseases, deposition of extracellular matrix (ECM) in alveoli and degradation of ECM lead to pulmonary structural remodeling. The changes in ECM and the localization of matrix metalloproteinases (MMPs) and a tissue inhibitor of metalloproteinases (TIMP) in the lung tissues of patients with bronchiolitis obliterans organizing pneumonia (BOOP) and idiopathic pulmonary fibrosis (IPF) were investigated. Immunohistochemical analysis for the detection of fibronectin, collagen-I, -III, and -IV, smooth muscle actin, MMP-1 (interstitial collagenase), -2 (gelatinase A), and -9 (gelatinase B), and TIMP-2, and in situ hybridization for the detection of MMP-9 mRNA were performed. Western blotting of lung tissue homogenates was performed for MMP-2 and MMP-9. The gelatinolytic activities of the homogenates were also determined using gelatin zymography. Fibronectin and collagen-I, -III, and -IV were detected in the intra-alveolar fibrosis in addition to the interstitium of these diseases. MMP-1, MMP-2, MMP-9, and TIMP-2 were detected in the regenerated epithelial cells covering intra-alveolar fibrosis. Myofibroblasts in intra-alveolar fibrosis in BOOP showed predominant reaction for MMPs, and they ultrastructurally appeared to be phagocytosing collagen fibrils, and those of IPF showed a predominant reaction for TIMP-2. New vascularization in intra-alveolar fibrosis was exclusively observed in cases of BOOP, and the endothelial cells were positive for MMP-2. Western blotting showed the existence of a latent form of MMP-9 and latent and active forms of MMP-2, and gelatin zymography revealed that the ratio of active/latent forms of MMP-2 in BOOP is significantly larger than that in the control lungs. Predominant MMPs in BOOP may constitute the mechanism of reversibility of fibrotic changes in this disease. TIMP-2 in myofibroblasts in IPF may contribute to the stable ECM deposition and the irreversible pulmonary structural remodeling.     

Role of growth factors in mesangial cell ion channel regulation

Our single channel work has characterized two ion channels capable of depolarizing mesangial cells and activating classic, voltage-activated Ca2+ channels in response to growth-stimulatory peptides (such as Ang II, ET and insulin): (1) Ca(2+)-dependent, 4 pS Cl- channel promoting Cl- efflux; and (2) Ca(2+)-dependent, 27 pS nonselective cation channels promoting cation influx. We have also characterized a third channel which provides an alternative, receptor-operated pathway for Ca2+ entry in response to the growth factor, PDGF: (3) Ca(2+)-permeable, 1 pS cation channel. Consistent with our model of mesangial cell signal transduction (Fig. 1), these three mesangial cell ion channels are activated by binding of growth factors to membrane receptors (Fig. 8). Defective channel regulation, such as occurs in early diabetes mellitus, would promote mesangial cell relaxation and pathogenic glomerular hyperfiltration. Glomerular hyperfiltration and hypertension have been proposed to be major pathogenic factors in renal disease progression [4, 29, 38, 39]. Compensatory renal growth factor responses initially provide adaptive changes in glomerular hemodynamics after loss of functional renal mass. However, chronic stimulation of these mesangial cell ion channels by renal growth factors would promote sustained extracellular Ca2+ entry, resulting in mesangial cell contraction and growth, and progressive decreases in Kf and GFR. Eventually, this process leads to irreversible renal damage due to the development of glomerulosclerosis and interstitial fibrosis.     

Nitric oxide stimulates the activity of a 72-kDa neutral matrix metalloproteinase in cultured rat mesangial cells

We recently demonstrated that stimulation of inducible nitric oxide synthase (iNOS) activity reduced the accumulation of collagen and fibronectin in cultured rat mesangial cells. Therefore, we examined whether nitric oxide (NO) influenced the activity of a 72 kDa neutral matrix metalloproteinase by these cells in vitro. Enzyme activity was assessed in a biotin-avidin ELISA and by zymography. Exposure of mesangial cells to the cytokines, interferon (IFN)-gamma and lipopolysaccharide (LPS), increased gelatinolytic activity by 325 +/- 60% (P < 0.025). Co-incubation with 20 mM L-arginine caused a further increase in matrix metalloproteinase levels. Addition of L-NAME, an inhibitor of iNOS, reversed the IFN-gamma/LPS-induced rise in gelatinolytic activity. Incubation with the exogenous NO donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP), resulted in a dose dependent increase in metalloproteinase activity (P < 0.01). The NO-induced changes in metalloproteinase activity were also demonstrable by zymography. These data indicate that NO modulates the activity of a 72 kDa neutral matrix metalloproteinase and suggest that altered NO production may contribute to the development of glomerulosclerosis and tubulointerstitial fibrosis in chronic renal disease states.     

Defective phagocyte adherence in acute poststreptococcal glomerulonephritis: clinical and laboratory observations

The adherence of circulating phagocytes to glass was studied in 15 children with acute poststreptococcal glomerulonephritis and in 27 healthy adults, 21 healthy children, and 14 children with normocomplementemic renal disease. The phagocytic adherence to glass in the patients with hypocomplementemic PSGN differed significantly from that of the control groups (p=less than 0.001). There was a positive correlation of phagocyte adherence with plasma C3 but not with plasma C4, C3, properdin factor B, severity of illness, or drugs administered. In addition, the adherence defect was present in two normocomplementemic PSGN patients. The defect gradually resolved in all patients with clinical improvement: it was useful as an index of recovery. The in vitro addition of functional C3 to whole blood produced the adherence defect in normal subjects and failed to correct the defect in patients with PSGN. It was postulated that a fragment of activated complement may have blocked a membrane receptor on these phagocytes and interfered with their adherence to glass.     

Decorin, biglycan and their endocytosis receptor in rat renal cortex

BACKGROUND: Among the small proteoglycans, biglycan and decorin have been proposed to be potent modulators of TGF-beta-mediated inflammatory kidney diseases. They were considered to become induced during glomerulonephritis and to subsequently inactivate the cytokine. METHODS: Decorin and biglycan as well as their endocytosis receptor were investigated in normal rat renal cortex, in anti-Thy-1 glomerulonephritis, in polycystic kidneys, in the remnant kidney following 5/6-nephrectomy, and in kidneys from the Milan normotensive strain by immunohistochemistry and in situ hybridization. Northern blots were used for the detection of mRNA expression for decorin and biglycan in isolated glomeruli. Functional aspects of the endocytosis of decorin and biglycan were studied in cultured mesangial cells. RESULTS: In the normal adult rat kidney decorin was expressed preferentially by Bowman's capsule and by interstitial connective tissue cells, but only in trace amounts by mesangial cells. In contrast, biglycan was found in tubular epithelial cells, in association with glomerular capillaries, podocytes and occasionally in the mesangium. In the tubulointerstitium of diseased kidneys (polycystic kidneys, 5/6-nephrectomy, kidneys from the Milan normotensive strain) there was a general up-regulation of decorin expression, while biglycan was localized only in distinct foci of fibrotic lesions. Glomerulosclerosis (5/6-nephrectomy, Milan normotensive strain) was associated with an increased staining for both decorin and biglycan within glomeruli. However, even in the anti-Thy-1 model of an acute mesangioproliferative glomerulonephritis where the greatest accumulation of decorin was found there was only a slight enhancement of decorin mRNA in isolated glomeruli. Decorin and biglycan become degraded upon receptor-mediated endocytosis. Immunohistochemical investigations indicated that the pattern of expression of the receptor protein correlated well with the immunolocalization of both decorin and biglycan. In vitro experiments with cultured mesangial cells provided direct evidence for the expression of the receptor and for the cell's capability to endocytose decorin as well as biglycan. CONCLUSIONS: Decorin and biglycan are characterized by a distinct expression pattern in the normal rat kidney, whereas the presence of their endocytosis receptor protein correlates with the expression of both proteoglycans. Decorin is almost completely absent in the normal mesangium. Both proteoglycans become up-regulated in various models of renal disease. The mesangial accumulation of decorin in the anti-Thy-1 glomerulonephritis that is observed in spite of the only slightly enhanced mRNA expression could result from decreased decorin turnover and/or increased mesangial retention.     

Enhanced IL-1 beta and tumor necrosis factor-alpha release and messenger RNA expression in macrophages from idiopathic pulmonary fibrosis or after asbestos exposure

Idiopathic pulmonary fibrosis (IPF) and asbestosis are fibrotic interstitial lung diseases characterized by alveolar wall fibrosis with accumulation of extracellular matrix, interstitial remodeling, and increased numbers of activated alveolar macrophages. Animal models and in vitro studies have shown that macrophage cytokines, namely IL-1 beta and TNF-alpha, play significant roles in the development of fibrosis. We found significant increases for TNF-alpha release in both diseases (p < 0.01) and a significant increase for IL-1 beta release in asbestosis compared to normal controls (p < 0.01). Also, the mRNA expression of these cytokines was increased in alveolar macrophages from patients with IPF or asbestosis compared with normals. The level of TNF-alpha release in macrophage supernatants correlated with the number of neutrophils per milliliter bronchoalveolar lavage fluid returned. Chrysotile, crocidolite, amosite asbestos, and silica stimulated IL-1 beta and TNF-alpha release and up-regulated their respective mRNA in macrophages or monocytes. To evaluate the role of IL-1 beta and TNF-alpha in the accumulation of extracellular matrix, we studied collagen types I and III and fibronectin gene expression in human diploid lung fibroblasts after short term (2 h) serum-free exposure to recombinant cytokines. Both cytokines up-regulated these genes 1.5- to 3.6-fold. These cytokines have the potential to influence the remodeling and fibrosis observed in the lower respiratory tract in IPF and asbestosis.     

An immunological correlation between the anchoring filaments of initial lymph vessels and the neighboring elastic fibers: a unified morphofunctional concept

More than 25 years have passed since immunoglobulin A (IgA) nephropathy was introduced as a disease entity independent of glomerulonephritis. It has been known that more than 30% of cases have gone into end-stage renal failure within 20 years, indicating the presence of a chronic active group in this disease. Histologically this disesase is composed of at least three types of tissue damage: (i) minimal inflammation including deposition of IgA-containing substances with minor matricial increase; (ii) acute lesions characterized by matricial damage of glomerular basement membrane (membranolysis) and/or mesangial matrix (mesangiolysis) with inflammatory cell accumulation and/or intrinsic cell proliferation; and (iii) chronic lesions mainly composed of postinflammatory sclerosis. The progression is actually accelerated by the frequency of acute lesions, resulting in increased glomerular sclerosis foci. In such a situation, the histologic grading and staging (G-S) system is proposed, with the aim of having a more precise understanding of the disease process. The histological grade (G) is estimated by the extent of acute glomerular and tubulointerstitial lesions, and the stage (S) is evaluated by the increase of extracellular matrices of the glomeruli and interstitial fibrosis. The evaluation of G and S is expressed semiquantitatively for more helpful clinical use.     

PAF-antagonists with lipid structure. 6. Alkylpropandiol lipids with acyl- and ether- structures at the C-3 position and heterocyclic head groups; synthesis, characterization and structure-activity relationship

OBJECTIVE: To investigate whether nonenzymatic glycated end products (AGEs) have effects on the expression and bioactivity of plasminogen activator inhibitor-1 (PAI-1), one of the seripin proteinases, which lead to extracellular matrix (ECM) degradation in cultured human mesangial cells. METHODS: Human mesangial cells (HMC) were cultured. Cell proliferation, fibronectin production, mRNA expression and bioactivity of PAI-1 were determined after exposure to AGE-BSA for 24 hours and 48 hours in vitro. RESULTS: HMC stimulated by AGE-BSA exhibited inhibition in HMC proliferation, increase in fibronectin production, and PAI-1 bioactivity. These changes were pronounced with prolongation of experimental time. PAI-1 mRNA expression increased significantly at 24 hr (0.45% +/- 0.06% vs 0.65% +/- 0.08%, P < 0.05), however more marked increase of PAI-1 mRNA expression at 48 hr (0.51 +/- 0.08% vs 0.92 +/- 0.10%, P < 0.01). CONCLUSIONS: Increase of mRNA expression and bioactivity of PAI-1 induced by AGEs decreased ECM degradation and play an important role in the pathogenesis of ECM accumulation and glomerulosclerosis.     

Mesangial involvement in hemolytic-uremic syndrome. A light and electron microscopic study

Electron microscopic analysis of the mesangial injury in the hemolytic-uremic syndrome was performed in 10 patients. Proteinaceous material similar to that found in the subendothelial region was also seen focally in the mesangium altering the matrix and imparting a reticular appearance. This degenerative process was associated with reparative changes in the glomerular tuft. Many of the mesangial cells were hypertrophied and demonstrated phagocytic activity and peripheral extension of their cytoplasmic processes. Mitotic figures in endothelial as well as mesangial cells were regarded as evidence of a reparative process. Severe mesangial insudation of material containing fibrinogen derivatives resulted in segmental tuft necrosis with almost complete replacement and destruction of the mesangial matrix. On some occasions, a break of the glomerular basement membrane was accompanied by the escape of intraluminal contents into the urinary space, leading to crescentic epithelial cell proliferation.