Transforming growth factor-beta. Murine glomerular receptors and responses of isolated glomerular cells

Proliferation of resident glomerular cells and the accumulation of mesangial matrix are histologic abnormalities which are observed in the course of many progressive glomerular diseases. We explored the potential regulatory effects of transforming growth factor-beta (TGF-beta) on these processes. We found that cultured mouse glomerular endothelial, mesangial, and epithelial cells as well as isolated intact rat glomeruli possess high-affinity receptors for TGF-beta. We also found that, although TGF-beta consistently inhibited the proliferation of glomerular endothelial and epithelial cells, it acted as a bifunctional regulator of mesangial cell proliferation. TGF-beta significantly increased the production of collagen and fibronectin by glomerular mesangial cells whereas only fibronectin production was augmented in glomerular epithelial cells. The presence of TGF-beta receptors on intact glomeruli and on each glomerular cell type and the demonstrated responsiveness of these cells to TGF-beta combine to suggest that potentially important interactions may occur between resident glomerular cells and TGF-beta in vivo.

Insulinlike growth factor-1 is a progression factor for human mesangial cells

Mesangial cell hyperplasia is a feature common to several human glomerular diseases. The cause of this increased cell number is unknown. The authors assessed human mesangial cells in vitro and found that they possessed an insulinlike growth factor-1 (IGF-1) receptor consisting of alpha and beta units (Mr, 130 k and 90 k respectively). Fifty percent inhibition of IGF-1 specific binding to the receptor required 1 X 10(-9) M IGF-1, greater than 1 X 10(-6) M insulin and 1 X 10(-7) M multiplication stimulating activity (MSA). Analysis of binding by the method of Scatchard revealed one type of IGF-1 receptor with a Kd of 1.35 X 10(-9) M, and a number per cell of 1.04 X 10(5). Binding studies on whole glomeruli had similar specificity and there were 7.17 X 10(7) receptors per glomerulus (Kd, 1.12 X 10(-9) M). Examination of the effect of IGF-1 on the cell cycle revealed that exposure of cells to both IGF-1 and platelet-derived growth factor (PDGF) led to a significant increase in 3H-thymidine incorporation into cell layers. Antibody to PDGF abolished only that response due to PDGF. Similarly, the labeling index of cells pretreated with PDGF, washed, and then exposed to IGF-1 was increased, whereas if the order of ligand exposure was reversed, there was no such additive effect. Finally, PDGF increased RNA and protein synthesis, and this response was not enhanced by IGF-1. In summary, human mesangial cells and whole glomeruli possess IGF-1-specific receptors and IGF-1 was found to act as a progression factor in the cell cycle.

Synthesis and release of insulinlike growth factor I by mesangial cells in culture

Mesangial cell proliferation is a common hallmark of many glomerular diseases. The exact mechanisms inducing cell proliferation in glomerulosclerosis are not completely understood, and it remains to be determined whether growth factors play a role in this process. Insulinlike growth factor I (IGF I) has been shown to be synthesized in the kidney, and glomerular mesangial cells have receptors for and exhibit mitogenic response to IGF I. We found that mouse glomerular mesangial cells in culture synthesized and released into the culture medium a molecule with immunological and biological features of IGF I. This molecule specifically bound to mesangial cell IGF I receptors; high-pressure liquid chromatographic analysis provided further evidence of its similarity to human recombinant IGF I. Mesangial cells released into the culture medium 6 ng/10(6) cells of IGF I-like material per 24 h in a time-dependent and actinomycin-D inhibitable fashion. These data suggest that IGF I might be locally released by mesangial cells in the glomerulus and act in an autocrine and paracrine fashion.

Studies on binding and mitogenic effect of insulin and insulin-like growth factor I in glomerular mesangial cells

The mesangial cells, as part of their smooth muscle cell function, are actively involved in regulating glomerular hemodynamics. Their overlying endothelium is fenestrated; therefore, these cells are directly exposed to plasma substances, including hormones such as insulin and insulin-like growth factor I (IGF-I). These peptides may contribute to the mesangial sclerosis and cellular hyperplasia that characterize diabetic glomerulopathy. We report herein the characterization of the receptors and the mitogenic effects of IGF-I and insulin on mouse glomerular mesangial cells in culture. The IGF-I receptor was characterized on intact cells. The Kd of the IGF-I receptor was 1.47 X 10(-9) M, and the estimated number of sites was 64,000 receptors/cell. The binding was time, temperature, and pH dependent, and the receptor showed down-regulation after exposure to serum. The expression of the receptor did not change on cells at different densities. The specific binding for insulin was too low to allow characterization of the insulin receptor on intact cells. However, it was possible to identify the insulin receptor in a wheat germ agglutinin-purified preparation of solubilized mesangial cells. This receptor showed the characteristic features of the insulin receptor, including pH dependence of binding and a curvilinear Scatchard plot. The mitogenic effects of insulin and IGF-I on mesangial cells were measured by the incorporation of [3H]thymidine into DNA. IGF-I was more potent than insulin. The half-maximal response to IGF-I stimulation occurred at 1.3 X 10(-10) M, and a similar increase with insulin was observed at concentrations in the range of 10(-7) M, suggesting that this insulin action was mediated through the IGF-I receptor. These data show that the mouse microvascular smooth muscle cells of the glomerulus express a cell surface receptor for IGF-I in vitro and that this peptide is a potent mitogen for these mesangial cells. It may, therefore, play a role in glomerular proliferative lesions. The insulin receptor is present in small numbers and does not mediate mitogenesis in mesangial cells.

Progressive glomerulosclerosis develops in transgenic mice chronically expressing growth hormone and growth hormone releasing factor but not in those expressing insulinlike growth factor-1

An increase in glomerular size occurs in normal maturation after subtotal renal ablation and disease states such as diabetes mellitus. The role that growth hormone (GH), growth hormone releasing factor (GHRF), and insulinlike growth factor-1 (IGF-1) play in these processes has been investigated using transgenic mice chronically expressing these hormones. The glomeruli were enlarged in all 3 strains of mice. Mesangial proliferation followed by progressive glomerulosclerosis was observed in the GH and GHRF animals only. In the IGF-1 mice the large glomeruli remained morphologically normal except for the enlargement. These data suggest that the glomerulosclerosis was due, in part, to disordered mesangial cell growth in response to circulating GH. The mesangial lesions in mice with chronically high plasma GH levels mimicked those in human diabetes mellitus. These models provide a means to study the hormonal regulation of glomerular growth and the role that specific hormones might play in the pathogenesis of glomerulosclerosis.

Glomerular epithelial, mesangial, and endothelial cell lines from transgenic mice

The culture of glomerular cells has represented an important tool in the understanding of individual glomerular cell functions. However, the complexity of the glomerulus has made it difficult to obtain pure cell populations. It has also been difficult to culture glomerular endothelial cells, even as mixed cell populations. At present there are no established glomerular cell lines from any source. We have established permanent cell lines of cloned glomerular epithelial, mesangial, and endothelial cells from a line of mice transgenic for the early region of simian virus 40 (SV40). These mice appear normal at birth but by three to four months of age have sclerosis affecting a variable percentage of their glomeruli. The cells maintain features characteristic of their normal counterparts despite their transformed phenotype. These cell lines could be useful tools in understanding the pathogenesis of glomerulosclerosis in this transgenic mouse model and in studying those features of normal glomerular cell biology which are not altered by a transformed phenotype.

Glomerulosclerosis and renal cysts in mice transgenic for the early region of SV40

Considerable evidence indicates that genetic determinants play a major role in the pathogenesis of a variety of human and experimentally-induced renal diseases. There are, however, no firm data to indicate which genes or types of genes can induce or promote renal disease. The recently acquired ability to make specific alterations in the genetic background of an animal affords a unique opportunity to assess the effect(s) of a given gene on the structure and function of an organ of interest. Such modifications have been carried out in the creation of transgenic mice. We examined mice transgenic for the transforming gene encoding large T-antigen which is present in the early region of simian virus 40 (SV40). Renal lesions were present in most animals. While there was some heterogeneity in the type and severity of the renal lesions observed, a majority of the older mice displayed glomerulosclerosis and/or proliferative tubular lesions which in some were associated with multiple, large tubular cysts. The appearance of these lesions in mice transgenic for a transforming gene suggests that renal expression of a gene which controls cell proliferation may be associated with the development of glomerulosclerosis and renal cysts. These findings indicate a possible role for other transforming genes, or oncogenes, in the pathogenesis of glomerulosclerosis and cystic renal disease in humans and other animal models.

Studies of progressive glomerular sclerosis in the rat

To obtain a better understanding of the sequential development of sclerosis in immune glomerular disease, the authors induced experimental membranous nephropathy in unilaterally nephrectomized rats and evaluated the lesions that developed over a 35-week period. Serial renal biopsies were examined by light and immunofluorescence microscopy for IgG, C3, neoantigens of the membrane attack complex (MAC), and interstitial (Type III) and basement membrane (Type IV) collagen. Urinary protein excretion increased from 208 +/- 19 mg/day to 308 +/- 36 mg/day during the period of observation. Progressive mesangial sclerosis, crescent formation, and interstitial fibrosis developed in association with deposition of Type IV but not Type III collagen in the glomeruli. Capillary wall deposits of IgG, C3, and MAC gradually decreased, whereas coarse granular deposits of C3 and MAC were visible in sclerotic areas beginning at 8 weeks. The appearance of complement components in early sclerotic lesions raises the possibility that they are of pathogenetic importance. The absence of interstitial collagen in sclerotic glomeruli suggests that the components of the lesion are produced solely by glomerular cells.

Lipopolysaccharide-mediated injury to cultured human glomerular endothelial cells

Lipopolysaccharide induced a dose-dependent detachment of human glomerular cells in vitro. The detachment occurred 24 hr after exposure to endotoxin. Human umbilical vein endothelial cells were not affected by more prolonged exposure or higher concentrations of lipopolysaccharide in the medium. The lipopolysaccharide effect was independent of complement components or leukocytes.

Glomerular cell culture

Glomerular cell culture has now become a widely used research technique. At the present time procedures are available to obtain isolated glomeruli from nearly all species. The isolation of individual cells has proven problematical. This is due to the lack of defined markers. Thus, it is not yet possible to determine the presence and relative degree of contamination by other glomerular or even nonglomerular, cell types. The importance of dealing with individual cell types, or defined mixtures, is exemplified by the variable results obtained in the assessment of prostaglandin synthesis within and between species. Several important bits of information have, nevertheless, evolved from glomerular cell culture experiments. The sites of synthesis of basement membrane components, as well as their composition, have been determined. Confirmation of the existence of a bone marrow-derived mesangial cell population and some of their properties has been obtained. The response of mesangial cells to, as well as their production of, various mediators has been shown. Finally, clear evidence for interspecies differences and similarities has been documented. Areas of controversy remain, including whether contractile mesangial cells are phagocytic, the presence of C3b receptors on epithelial cells, the amounts and types of certain extracellular matrix products synthesized by the various cell types, and the best methods for separation and culture of the individual glomerular cell types. There remain many fruitful areas for research. Fundamental questions such as the appropriate basal medium and supplements, the type of substrate, and the means to separate the individual cell types remain as unanswered or partially answered questions. When isolated cells are reliably obtained, the study of biosynthetic products in the resting and stimulated states must be again addressed. At that point, the effect of various and deliberate combinations of the glomerular cell types on the biosynthetic or proliferative responses will require further studies. For instance, although contractility mediated by receptors for angiotensin II has been assumed to be a specific property of mesangial cells, recent work shows that epithelial cells also respond to angiotensin II. In addition, the handling of immune complexes by various cells needs to be further investigated (43). Similarly, the pharmacologic response of the diverse populations of glomerular cells represents another area of study that has just begun. Finally, these data will provide the backdrop on which the analysis of various induced and genetic diseases can be performed.(ABSTRACT TRUNCATED AT 400 WORDS)

Extracellular matrix in normal and fibrotic human lungs

Polyclonal affinity-purified antibodies to human collagen types I, III, and IV, and laminin were used to compare the extracellular matrix (ECM) in 10 normal and 32 abnormal lungs by indirect immunofluorescence. In normal lungs, type IV collagen and laminin codistributed in a uniform linear pattern along the epithelial and endothelial basement membranes. Type III collagen was found within the alveolar septa and interstitium in an interrupted ribbonlike pattern and was aggregated at the entrance rings of the alveoli. Type I collagen was distributed irregularly within the alveolar wall and was less prominent than type III collagen. In patients with pulmonary disease not characterized by interstitial fibrosis (n = 15), the distribution of ECM components studied was essentially normal. In pulmonary disease in which interstitial fibrosis was the characteristic feature, such as idiopathic pulmonary fibrosis (IPF) and adult respiratory distress syndrome (ARDS) (n = 17), collagen types I and III accumulated in the expanded interstitium. Type III collagen was initially predominant in the thickened alveolar septa and interstitium, whereas type I collagen appeared to be the principal collagen at later stages in the disease course. The basement membrane was disrupted early in the disease course with invasion of the alveolar spaces by interstitial collagens similar in type to those present in the adjacent interstitium.

The composition of glomerulosclerosis. I. Studies in focal sclerosis, crescentic glomerulonephritis, and membranoproliferative glomerulonephritis

The composition of glomerulosclerosis was examined in focal sclerosis, membranoproliferative glomerulonephritis, and crescentic glomerulonephritis, using antisera specific for laminin and collagen types III and IV. Mesangial sclerosis consisted exclusively of extracellular matrix found in normal glomeruli, as did small synechiae in focal sclerosis and all synechiae in membranoproliferative glomerulonephritis. The large synechiae in focal sclerosis and all stages of the developing crescents associated with vasculitis contained mainly interstitial collagen, type III, a component not found in normal glomeruli. In the latter there were also disruptions of Bowman's capsule and an increase in the number of periglomerular interstitial cells. These observations suggested that glomerulosclerosis varied in composition and distribution, and some types of crescentic glomerulonephritis may have arisen from either cells resident in the glomerulus or cells coming from the interstitial space.

Localization of collagen types IV and V, laminin, and heparan sulfate proteoglycan to the basal lamina of kidney epithelial cells in transfilter metanephric culture

Mouse metanephric mesenchyme and embryonic spinal cord were cultured on opposite sides of a filter membrane. This resulted in formation of prenephronic vesicles after 36 hours in culture, S-shaped bodies after 2-3 days, and glomeruli and tubules after 4-7 days. The glomeruli consisted of an arborizing tuft of podocytes lying on a basement membrane without vascularization or a mesangial ingrowth. We have used antibodies to study the molecular composition of the nephron basement membrane at each stage of development. By immunofluorescence light microscopy, collagen Types IV and V, laminin, and heparin sulfate proteoglycan were expressed within the pericellular/intercellular matrix at the onset of morphologic differentiation. The molecules were organized into a linear basement membrane associated with epithelial cells during the prenephronic vesicle, S-shaped body, and glomerulus and tubule stages of development.

Isolation, characterization, and propagation in vitro of human glomerular endothelial cells

Human glomerular endothelial cells have been isolated, cloned, and characterized. They appeared as the first outgrowth from human glomeruli in the presence of platelet-derived growth factor, which was also a requirement for continuous growth. By phase microscopy they appeared as monolayers of polygonal cells. Von Willebrand's factor (VWF) was detected in the cytoplasm of all clones. Their intermediate filaments differed antigenically from that present in human umbilical vein endothelial cells. Like other endothelial cells, they demonstrated high levels of membrane-associated angiotensin-converting enzyme (ACE).

Glomerular localization of preformed immune complexes prepared with anionic antibodies or with cationic antigens

The glomerular basement membrane presents a highly anionic surface to circulation. The effects of anionic antibody and cationic antigen in preformed immune complexes prepared at 5-fold antigen excess were investigated in separate experiments in mice. Anionized antibodies (isoelectric point 4 to 6) to human serum albumin were prepared by acetylation and immune complexes produced in vitro. Blood clearance kinetics and glomerular immunofluorescence patterns of these immune complexes were not affected by anionization . Electron microscopy revealed mesangial deposits, indicating that the deposition of immune complexes in the mesangium occurs with highly anionic immune complexes. Cationic human serum albumin (AgED, isoelectric point 7.5 to 9.0) alone or as performed immune complexes ( AgEDAb ) showed rapid blood clearance (less than 1% remaining by 18 hours) and localized in renal glomeruli by immunofluorescence microscopy. AgED injected alone was present in glomeruli at 1 minute after injection but was absent at 12 hours. After injection of AgEDAb , both antigen and antibodies were present in glomeruli from 1 minute through 72 hours by immunofluorescence microscopy. Electron-dense deposits were seen at the anionic sites in the lamina rara interna and lamina rara externa at 1 minute and 1 hour after injection of AgED and AgEDAb containing free AgED. After AgEDAb injection electron-dense deposits were evident at 12 to 48 hours in the mesangium and in the subendothelial area, especially adjacent to the mesangium. By 72 hours after AgEDAb injections mesangial deposits predominated, although small subepithelial deposits were also present. An inflammatory reaction was noted in the glomeruli after administration of AgEDAb . Thus, preformed immune complexes containing cationized antigen show glomerular deposition, primarily in the subendothelial and mesangial regions and at later time points also in the subepithelial area.

Granular pneumocytes in primary culture secrete several major components of the extracellular matrix

Primary cultures of rat alveolar type II epithelial cells (granular pneumocytes) produced several components of the pulmonary extracellular matrix. Fractionation by ion-exchange chromatography of radiolabeled protein secreted into the culture medium resulted in the partial purification of two of these components: fibronectin and type IV procollagen. Identification of these proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was confirmed by radioimmune-precipitation studies with affinity-purified antibodies. Thrombospondin, a platelet alpha-granule protein that was recently shown to be secreted by endothelial and other mesenchymally derived cells and may be involved in platelet aggregation, was, in addition, purified by elution from diethylaminoethylcellulose with 0.5 M NaCl. The levels of these secreted proteins were measured by radioimmune precipitation. Of the total radiolabeled culture medium protein secreted during a 24-h period by the granular pneumocytes, fibronectin, type IV procollagen, and thrombospondin represented 3-15%, 2%, and 3%, respectively. The biosynthesis, by alveolar epithelial cells, of proteins that constitute or are closely associated with the alveolar basement membrane implies that this structure is at least partially derived from the cells themselves. Furthermore, it suggests that the type II epithelial cell is involved in pulmonary cytodifferentiation, in lung morphogenesis and repair, and in certain interstitial lung disorders in which derangement of the extracellular matrix occurs.

Lipopolysaccharide-mediated bovine endothelial cell injury in vitro

Lipopolysaccharide (LPS) produced time- and dose-dependent bovine endothelial cell injury in vitro that was manifested initially by cell detachment from culture substrate with subsequent cell lysis. Bovine endothelial cell injury was observed with LPS derived from Salmonella minnesota R595, a LPS comprised only of lipid A and a trisaccharide core, as well as intact LPS preparations derived Escherichia coli and S. typhosa. LPS-mediated bovine endothelial cell detachment was prevented by incubation at 4 degrees C but was not prevented by indomethacin, lidocaine, chlorpromazine or trifluoperazine, methylprednisolone or p-bromophenacyl bromide, protease inhibitors, and catalase or superoxide dismutase. Of note, LPS-mediated injury was markedly enhanced by cycloheximide. Although augmented by serum, LPS-mediated bovine endothelial cell detachment was observed in C8-deficient serum and also in serum-free medium at higher LPS concentrations. Bovine aortic, pulmonary artery, mesenteric artery, and mesenteric vein endothelial cells were all sensitive to LPS at a concentration of 1 microgram/ml. In contrast, bovine aortic smooth muscle, human umbilical vein, goat aortic, and canine vena cava endothelial cells were unaffected by LPS at a concentration of 100 micrograms/ml. We conclude that the lipid A moiety of LPS mediates direct, complement-independent endothelial cell cytotoxicity and that this injury is not prevented by inhibitors of protein and prostaglandin synthesis, oxygen radical production, protease and phospholipase activity, and cytoskeletal function. Importantly, this direct LPS-mediated cytotoxic effect is dependent on the species from which the endothelial cells are derived.

Effects of lipopolysaccharide on human endothelial cells in culture

Lipopolysaccharide (LPS) in concentrations up to 10 micrograms/ml did not induce detectable direct cytotoxicity in human umbilical vein, pulmonary artery, or pulmonary vein endothelial cells. By contrast, significant cytotoxicity was observed in bovine aortic endothelial cells exposed to LPS 0.01 micrograms/ml. Transmission electron microscopy of human umbilical vein cells exposed to LPS 10 micrograms/ml for 4 days revealed no significant ultrastructural abnormalities compared to control cells. Whereas human umbilical vein endothelial cell cytotoxicity was observed when neutrophils were stimulated with phorbol myristate acetate, LPS-stimulated neutrophils did not induce significant cytotoxicity even in the presence of fresh human serum as a complement source. Moreover, human umbilical vein endothelial cell factor VIII-antigen and fibronectin release, angiotensin-converting enzyme activity, and PGI2 release were unaffected by a 24-hour exposure to LPS. Cytotoxicity, however, was produced when human umbilical vein endothelial cells were coincubated with LPS and cycloheximide. The proliferation of human umbilical vein endothelial cells was also inhibited after prolonged, continuous exposure to LPS 10 micrograms/ml. We conclude that LPS with or without complement or neutrophils does not induce significant human endothelial cell lysis or detachment. Moreover, brief exposure to LPS has minimal, direct effect on several functions of human endothelial cells in vitro.

The disappearance kinetics and glomerular deposition of small-latticed soluble immune complexes

The disappearance from circulation and the glomerular localization of human serum albumin (HSA) anti-HSA complexes made at fifty-fold antigen excess were examined in mice and compared with the same features of complexes made at five-fold antigen excess. Complexes prepared at fifty-fold antigen excess consisted principally of small-latticed complexes (Ag2Ab2 and Ag1Ab1) that persisted in the circulation after the initial rapid disappearance attributed to extravasation. The presence of small-latticed complexes in the circulation did not lead to glomerular localization of complexes during a 96 hr period. In contrast, when large-latticed soluble complexes, prepared at five-fold antigen excess, were injected, abundant glomerular deposits developed. These observations indicate that the lattice of circulating immune complexes must exceed the Ag2Ab2 structure in order for glomerular deposition to occur.

Effect of cationized antibodies in performed immune complexes on deposition and persistence in renal glomeruli

To study the interaction of positively charged antibodies in immune complexes with the fixed negative charge on the glomerular capillary wall, chemical cationization of antibody was accomplished with the maintenance of antigen-binding activity. These cationized antibodies bound rapidly to glomeruli but did not persist. Large-latticed immune complexes formed with these cationic antibodies showed rapid deposition and persistence in renal glomeruli, even when administered in small doses. Electron-dense deposits were present at the anionic sites in the glomerular basement membrane at 1 min and 1 h, with extensive subendothelial deposits present from 12 to 72 h. By 14 d, the deposits were seen in the subepithelial region and the glomerular mesangium. The administration of small-latticed immune complexes prepared with cationized antibody revealed initial deposition without persistence in glomeruli in a manner similar to cationized antibodies alone. Thus, the positive charges on antibodies in immune complexes contribute to the deposition and persistence of the complexes in glomeruli, particularly in the subendothelial area.

Donor origin of the in vitro haematopoietic microenvironment after marrow transplantation in man

The method for long-term culture of marrow cells in vitro as described by Dexter has recently been successfully applied to human marrow and is dependent on the development of an adherent stromal cell layer consisting of cells described as "endothelial-like cells, fat cells, and macrophages". The present study was designed to determine the origin and composition of the stromal cells forming the in vitro 'microenvironment' and maintaining haematopoiesis in long-term cultures grown from marrows of 14 patients who received marrow transplants from HLA identical siblings of the opposite sex. The presence of a Y chromosome was used as a marker to establish the donor or recipient origin of the cells. We found that the stromal cells became progressively donor in origin with time after transplantation and some reacted with antibody directed against factor VIII-associated antigen. In addition, donor-derived in vitro stromal cells synthesized both interstitial and basal lamina collagen types, indicating that the in vitro microenvironment is transplantable and composed in part of endothelial-like cells.

Neutrophil-mediated endothelial injury in vitro mechanisms of cell detachment

Neutrophil-mediated endothelial injury was assessed in vitro using assays of cell lysis and cell detachment. Activation of human peripheral blood neutrophils adherent to human umbilical vein endothelial cell monolayers by serum-treated zymosan produced dose-dependent endothelial cell detachment without concomitant cell lysis. This injury was inhibited by neutral protease inhibitors, but not by catalase or superoxide dismutase. Neutrophils from a patient with chronic granulomatous disease also produced endothelial cell detachment when activated by serum-treated zymosan similar to normal neutrophils. Endothelial detachment was also produced by cell-free postsecretory media from activated neutrophils or by partially purified human neutrophil granule fraction and was inhibitable by tryptic, elastase, and serine protease inhibitors, but not by an acid protease inhibitor. Analysis of iodinated endothelial cell surface proteins that had been exposed to partially purified neutrophil granule fraction showed complete loss of proteins migrating in the region of fibronectin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This result was prevented in the presence of neutral protease inhibitors. We conclude that neutrophil-derived neutral proteases mediate endothelial cell detachment in vitro through digestion of endothelial cell surface proteins including fibronectin.

Binding and release of factor VIII/von Willebrand's factor by human endothelial cells

The uptake and release of factor VIII/von Willebrand's protein by cultured human umbilical vein endothelial cells have been examined using highly purified 125I-factor VIII possessing von Willebrand's factor activity. 125I-factor VIII/vWF was taken up by the cells, reaching maximum binding within 4 h with a t1-2 of binding of 15 min. Endothelial cell binding of 125I-factor VIII/vWF reached saturation at a concentration of 1.5 mg/l. Binding was inhibited by coincubation of excess unlabelled factor VIII/vWF. Most of the cell-associated radioactivity was released by treatment of the cells with trypsin. Internalization of bound protein was evidenced by the incorporation into the cells of radioactivity which could not be released by trypsin. Human vascular smooth muscle cells did not bind 125I-factor VIII/vWF. Addition of 0.1 microM epinephrine to the 125I-factor VIII/vWF labelled endothelial cultures induced the release of cell bound, protein-associated radioactivity into the medium. Propranolol inhibited completely epinephrine-induced release, whereas phenylephrine had no effect. Endothelial cells maintained in medium partially depleted of factor VIII/vWF by tricalcium citrate cellulose treatment of plasma did not release factor VIII antigen into the culture medium during subsequent incubation. Although [3H]proline was incorporated into proteins released by endothelial cells under these experimental conditions, specific incorporation of label into factor VIII/vWF antigen was not detectable by a sensitive solid-phase immunoradiometric assay. We conclude that factor VIII/vWF binds to endothelial cells and that this cell-bound protein is mobilized by epinephrine through beta-adrenergic stimulation.

Human glomerular cells in vitro: isolation and characterization

Human glomerular cells were isolated, identified, and propagated in vitro, and a number of features were found to be unique to glomerular visceral epithelial and mesangial cells. Epithelial cells are identified by their "epithelial" morphology in vitro, growth pattern, presence of C3b surface receptors, response to mitogens, synthesis of a single collagen type (IV), and nearly exclusive synthesis of one type of sulfated glycosaminoglycan, heparan sulfate. Mesangial cells differ from epithelial cells and other potential contaminating cells, such as fibroblasts or endothelial cells, by their characteristic light and electron microscopic morphology and their synthesis of specific collagen and glycosaminoglycan types. In addition, while they closely resemble vascular smooth muscle cells in many ways, they differ with respect to their response to mitogens. It should now be possible to study these cells for other features, including the presence of alloantigens. This property and their response to inflammatory mediators or cells are prerequisites to the determination of their role in the pathogenesis of renal allograft rejection.

Chronic graft-versus-host syndrome in man. A long-term clinicopathologic study of 20 Seattle patients

This study of chronic graft-versus-host disease (GVHD) describes the clinical, pathologic and laboratory features, and the causes of morbidity and mortality in 20 patients who received allogeneic marrow transplants from HLA identical sibling donors. Chronic GVHD is a pleiotrophic syndrome with variability in the time of onset, organ systems involved and rate of progression. The clinical-pathologic features resemble an overlap of several collagen vascular diseases with frequent involvement of the skin, liver, eyes, mouth, upper respiratory tract, esophagus and less frequent involvement of the serosal surfaces, lower gastrointestinal tract and skeletal muscles. Major causes of morbidity are scleroderma with contractures and ulceration, dry eyes and mouth, pulmonary insufficiency and wasting. Chronic GVHD has features of immune dysregulation with elevated levels of eosinophils, circulating autoantibodies, hypergammaglobulinemia and plasmacytosis of viscera and lymph nodes. In this study, three patients had limited chronic GVHD with relatively favorable prognosis characterized by localized skin involvement and/or hepatic disease without chronic aggressive histology. Most patients, however, had extensive disease with a progressive course. Survival was largely determined by the presence or absence of serious recurrent bacterial infections. The over-all severity of disease was best assessed by using the Karnofsky performance rating.

Human glomerular visceral epithelial cells synthesize a basal lamina collagen in vitro

Isolated human glomeruli were digested with purified bacterial collagenase yielding epithelial cells. These cells grew to saturation density and did not become multi-layered. They were identified as visceral glomerular epithelial cells by their morphologic appearance by phase and electron microscopy and by the presence of surface receptors for C3b. Neither Factor VIII antigen nor Fc receptors were observed. The glomerular epithelial cells synthesized a collagenous protein that was antigenically similar to human glomerular basal lamina. Proteins precipitated from visceral epithelial cell medium with affinity purified antibody against noncollagenous glomerular basal lamina antigens yielded a single collagenase labile protein that by sodium dodecyl sulfate/polyacrylamide gel electrophoresis migrated with an apparent Mr of 168,000 in the presence of reducing agents. Analysis of hydroxyproline isomers yielded a ratio of 3-hydroxyproline to total hydroxyproline of 0.17. Pepsin digestion yielded a disulfide-bonded multimer which, with reduction, migrated with an apparent Mr of 148,000. These data demonstrate that human glomerular visceral epithelial cells can be isolated and propagated in vitro and that they synthesize a collagen similar to that found in vivo.

Role of marrow-derived monocytes and mesangial cells in removal of immune complexes from renal glomeruli

Phagocytosis of intravenously administered immune complexes by cells in the mesangium was investigated. The model used was that of exchange marrow transplantation between Chediak-Higashi (CH) mice and syngeneic partners after X-irradiation. This model was chosen since marrow-derived macrophages could be differentiated from resident mesangial cells by the presence of the characteristic giant lysosomes in phagocytic cells of the CH mice. Injected immune complexes were cleared normally and localized in the glomerular mesangium in CH or C57BL/6J mice receiving either C57BL/6J or CH marrow. C57BL/6J mice with CH marrow injected with immune complexes prepared with reduced and alkylated antibodies accumulated many cells within the mesangium that contained both giant lysosomes and electron dense deposits. Deposits were not found in cells with subplasmalemmal microfilaments and perpheral dense bodies. Conversely, the cells in the mesangium of CH mice with C57BL/6J marrow that contained electron dense deposits were devoid of giant lysosomes. Based on these observations, we concluded that (a) marrow-derived monocytes contribute to mesangial hypercellularity after deposition of immune complexes and (b) phagocytosis of immune complexes localized in the glomerular mesangium was by marrow-derived monocytes rather than by mesangial cells.

Factors influencing endothelial cell proliferation in vitro

The relative roles of blood cell products and plasma factors on endothelial cell proliferation were evaluated by studying the proliferative response of human umbilical vein endothelial cells to cell free plasma derived serum (CFPDS), whole blood serum (WBS), platelet released factors, fibroblast growth factor and macrophage conditioned medium in vitro. Human adult arterial smooth muscle cells were treated in a similar manner for comparison. The rate of endothelial cell proliferation was directly related to the concentrations of both WBS and CFPDS. Grwoth rate in WBS was marginally greater than that observed in CFPDS during early culture, however, similar confluent densities were achieved. The addition of platelet released factors to CFPDS did not further stimulate endothelial cell proliferation. In contrast smooth muscle cells were quiescent in CFPDS despite increasing serum concentrations, but proliferated actively in response to platelet released factors. Both human macrophage conditioned medium and fibroblast growth factor increased endothelial cell proliferation significantly when compared with CFPDS alone. It is concluded that endothelial cell proliferation in preconfluent cultures is dependent on plasma factors while human vascular smooth muscle cells also require cell derived mitogens such as platelet growth factor to proliferate. The release of a substance by human macrophages mitogenic for endothelial cells may be involved in endothelial cell proliferation in vivo.

The appearance of nonlinear deposits of immunoglobulins in Goodpasture's syndrome

A twenty year old woman presented with pulmonary hemorrhage and glomerulonephritis with linear deposition of IgG on the glomerular capillary basement membrane, and high titer of antiglomerular basement membrane antibody in her serum. Without treatment, renal function, which was transiently impaired, has improved, pulmonary hemorrhage subsided, and repeat renal biopsies have revealed the appearance of nonlinear in addition to the linear deposition of IgG on the glomerular capillary basement membrane in the face of diminished serum antiglomerular basement membrane antibody titer.

The glomerular deposition of soluble immune complexes prepared with reduced and alkylated antibodies and with intact antibodies in mice

The kidney localization and glomerular deposition of soluble immune complexes in mice were greater and more persistent following the intravenous administration of complexes prepared with reduced and alkylated antibodies than following the administration of complexes prepared with intact antibodies. The increased glomerular deposition following the administration of complexes prepared with reduced and alkylated antibodies was associated with the persistence of circulating complexes composed of more than two antigen and two antibody molecules (Haakenstad AO, Mannik M:Lab Invest 35:283, 1976). The deposition of immune complexes in glomeruli, as detected by immunofluorescence, appeared to precede the detection of mouse C3 in glomerular deposits following the administration of both preparations of complexes. The deposition of mouse C3 was more intense and persisted longer in mice receiving complexes containing reduced and alkylated antibodies than in mice receiving complexes containing intact antibodies. The ultrastructural studies indicated that both preparations of complexes initially localized as electron-dense material in endothelial cell fenestrae and in the subendothelial space of the glomerular capillary loops and subsequently accumulated in the mesangial matrix between mesangial cells. The material persisted in the mesangium of mice receiving complexes with reduced and alkylated antibodies, whereas it was removed from the mesangium of mice receiving complexes with intact antibodies. The mechanism for removal of complexes from the mesangial matrix was not defined, but it did not appear to occur through phagocytosis by the mesangial cell.

The adverse effect of high-dose steroids on renal autografts and homografts

We observed that canine renal homografts preserved for 5 hours with hypothermic pulsatile perfusion to which large doses of methylprednisolone were added showed obliteration of glomerular capillary loops by eosinophilic proteinaceous material immediately after revascularization. The lesion progressed to focal necrosis at 24 hours and diffuse necrosis by 5 days. Urine formation was present 7.8 (+/- 3.2 S.D.) days in eight control kidneys not exposed to methylprednisolone, 5.8 (+/- 3.8 S.D.) in 11 organs perfused with 1.0 Gm. of methylprednisolone added, and 3.0 (+/- 2.9 S.D.) in eight with 2.0 Gm. of the drug in the standard cryoprecipitated canine plasma perfusate. Autografts treated with the larger dose also showed a similar but temporally more variable lesion. Two kidneys ceased functioning at 4 and 7 days, and six still were functioning at 14 days. Ninety-four percent of human renal homografts from living related donors were functioning at one month and 82 percent at one year in 88 patients who had rejection crises treated with one gram of methylprednisolone or less intravenously. In 32 human recipients of living related donor grafts receiving 40 mg. per kilogram of methylprednisolone intravenously from days one to 3 postoperatively and for rejection crises, 69 and 59 percent were functioning at one month and one year, respectively. From this data we conclude that exercise doses of methylprednisolone are inadvisable in renal transplantation.

Renal microangiopathy of the hemolytic-uremic syndrome in childhood

18 children with clinical and laboratory findings characteristic of the hemolytic uremic syndrome were retrospectively studied. Thrombocytopenia due to platelet destruction was accompanied by only minimal changes in fibrinogen turnover and fibrinolytic degradation products. The most consistent pathologic feature was severe renal endothelial cell injury, which was postulated to produce both platelet and red cell destruction. Despite initially severe renal damage, 90% of the patients ultimately recovered normal renal function if adequately supported during the acute phase of the disease.