scholarly journals TRANSPORT OF GLOBIN BY THE RENAL GLOMERULUS

1964 ◽  
Vol 120 (6) ◽  
pp. 1129-1138 ◽  
Author(s):  
Max G. Menefee ◽  
C. Barber Mueller ◽  
Allen L. Bell ◽  
Joseph K. Myers
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Basement Membranes ◽  
Renal Glomerulus ◽  
Thin Sections ◽  
Characteristic Appearance ◽  
Pass Through ◽  
Surrounding Membrane ◽  
Glomerular Capillaries

Purified human globin injected into rats forms aggregates which are identifiable by their characteristic appearance in thin sections in the electron microscope and by their positive autoradiographs when the globin is tritiated before injection. Globin is taken up by endothelial cells of glomerular capillaries and is transported across the cell within the limits of a surrounding membrane. Globin is rarely seen to pass through fenestrations. Globin is also taken into the stalk region where it is seen usually within the sponge fibers and only occasionally within stalk cells. Globin is seen in all stages of passage through the basement membranes and sponge fibers, which are not deformed by its passage. On the basis of the findings presented here and by others, it is postulated that the basement membrane and sponge fibers consist of a thixotrophic gel. After traversing the basement membrane, the globin passes between foot processes of the epithelial cells. The slit membranes are deformed by this passage and thus appear to be distinctive structures. The globin is next found free in Bowman's space; the earliest aggregates are seen there within 1 minute after injection. Globin taken up in the stalk region is slowly discharged and very little is found there 6 hours postinjection.

Glomerulosclerosis in Canine Heartworm Infection

1974 ◽  
Vol 11 (6) ◽  
pp. 506-514 ◽  
Author(s):  
C. F. Simpson ◽  
B. M. Gebhardt ◽  
R. E. Bradley ◽  
R. F. Jackson
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Immune Complexes ◽  
Tissue Damage ◽  
Basement Membranes ◽  
Canine Heartworm ◽  
Heartworm Disease ◽  
Heartworm Infection ◽  
Glomerular Lesions ◽  
Glomerular Capillaries

The kidneys of seven dogs with natural infections of heartworm disease, four dogs with experimental infections, and six control (uninfected) dogs raised in isolation were examined by light, fluorescent, and electron microscopy. Swelling and fragmentation of the basement membranes accompanied by denudations of endothelial cells and fusion and atrophy of foot processes occurred in the glomeruli of dogs with heartworm disease, but not in control dogs. The severity of tissue damage correlated with the degree of microfilaremia. There was no evidence that the glomerular lesions were caused by immune complexes deposited in the basement membranes; and the alterations of glomerular capillaries were probably caused by motile microfilariae in the capillaries.

The relation between connective tissue cells and intercellular substances, including basement membranes

1975 ◽  
Vol 271 (912) ◽  
pp. 363-377 ◽  
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Immune Complexes ◽  
Hydrolytic Enzymes ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Cellular Level ◽  
Basement Membranes ◽  
The Body ◽  
Pathological Changes

Basement membranes are distributed widely in the body forming an extracellular matrix for epithelial and endothelial cells. The collagenous and glycoprotein constituents of basement membranes are synthesized by these two cell types. Disturbance of the interactions between basement membranes and their associated epithelial and endothelial cells can lead to the pathological changes seen in diseases involving basement membranes. These changes are illustrated here by reference to glomerulonephritis induced by the deposition of immune complexes in the glomerulus of the kidney, and chronic inflammatory changes occurring in the lung after inhalation of asbestos. In these diseases basement membrane changes can occur in several ways. Hydrolytic enzymes released from inflammatory cells degrade basement membranes while other factors released from these cells may stimulate synthesis of basement membrane constituents by epithelial and endothelial cells. Alternatively the physical separation of epithelial and endothelial cells from their basement membranes by space-occupying substances such as immune complexes can interfere with feedback mechanisms leading to synthesis of basement membrane constituents and cell proliferation. Studies of these pathological changes at a cellular level should shed new light on the ways in which cells interact with their pericellular environment.

scholarly journals Association of malachite green-positive material with heparan sulfate proteoglycan double tracks in basement membrane of mouse kidney tubules.

1995 ◽  
Vol 43 (3) ◽  
pp. 293-297
Author(s):  
S Inoue
Keyword(s):  
Basement Membrane ◽  
Heparan Sulfate ◽  
Malachite Green ◽  
Heparan Sulfate Proteoglycan ◽  
Mouse Kidney ◽  
Basement Membranes ◽  
Kidney Cortex ◽  
Sulfate Proteoglycan ◽  
Kidney Tubules ◽  
Thin Sections

The presence of lipids in the basement membrane of the mouse kidney tubules was examined by histochemical staining with malachite green. Pieces of mouse kidney cortex were immersed in a fixative containing 3% glutaraldehyde and 0.1% malachite green in 0.067 M sodium cacodylate buffer, pH 6.8, for 18 hr at 4 degrees C. Control tissue was fixed in the same way except that no malachite green was added to the fixative. The tissue pieces were cryoprotected, frozen in Freon 22, and subjected to freeze-substitution in dry acetone containing 1% OsO4. Thin sections of Epon-embedded specimens were observed by electron microscopy at first without uranyl-lead counterstaining. The basement membrane of mouse kidney tubules was positively stained in a pattern composed of an irregular assembly of 5-8-nm wide strands. The nature of these malachite green-positive strands was further examined by counterstaining thin sections with uranyl-lead, and they were identified as 4.5-5-nm wide ribbon-like "double tracks" previously characterized as the form taken by heparan sulfate proteoglycan in basement membranes. It is concluded that lipids are present in the basement membrane of mouse kidney tubules in association with heparan sulfate proteoglycan.

scholarly journals Evidence for splicing new basement membrane into old during glomerular development in newborn rat kidneys.

1986 ◽  
Vol 103 (6) ◽  
pp. 2489-2498 ◽  
Author(s):  
D R Abrahamson ◽  
E W Perry
Keyword(s):  
Basement Membrane ◽  
Colloidal Gold ◽  
Early Stage ◽  
Basement Membranes ◽  
Newborn Rat ◽  
Thin Sections ◽  
Intravenous Injections ◽  
Rabbit Igg ◽  
Glomerular Development ◽  
Rat Kidneys

Tannic acid in glutaraldehyde fixatives greatly enhanced the visualization of two developmentally and morphologically distinct stages in glomerular basement membrane (GBM) formation in newborn rat kidneys. First, in early stage glomeruli, double basement membranes between endothelial cells and podocytes were present and, in certain areas, appeared to be fusing. Second, in maturing stage glomeruli, elaborate loops and outpockets of basement membrane projected into epithelial, but not endothelial, sides of capillary walls. When Lowicryl thin sections from newborn rat kidneys were sequentially labeled with rabbit anti-laminin IgG and anti-rabbit IgG-colloidal gold, gold bound across the full width of all GBMs, including double basement membranes and outpockets. The same distribution was obtained when sections from rats that received intravenous injections of rabbit anti-laminin IgG 1 h before fixation were labeled directly with anti-rabbit IgG-colloidal gold. When kidneys were fixed 4 d after anti-laminin IgG injection, however, loops beneath the podocytes in maturing glomeruli were usually unlabeled and lengths of unlabeled GBM were interspersed with labeled lengths. In additional experiments, rabbit anti-laminin IgG was intravenously injected into newborn rats and, 4-14 d later, rats were re-injected with sheep anti-laminin IgG. Sections were then doubly labeled with anti-rabbit and anti-sheep IgG coupled to 10 and 5 nm colloidal gold, respectively. Sheep IgG occurred alone in outpockets of maturing glomeruli and also in lengths of GBM flanked by lengths containing rabbit IgG. These results indicate that, after fusion of double basement membranes, new segments of GBM appear beneath developing podocytes and are subsequently spliced into existing GBM. This splicing provides the additional GBM necessary for expanding glomerular capillaries.

scholarly journals STUDIES ON INFLAMMATION

1961 ◽  
Vol 11 (3) ◽  
pp. 571-605 ◽  
Author(s):  
G. Majno ◽  
G. E. Palade
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Blood Vessels ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Intercellular Junctions ◽  
Supporting Evidence ◽  
Electron Microscopic ◽  
Tracer Particles

The mechanism, whereby histamine and serotonin increase the permeability of blood vessels, was studied in the rat by means of the electron microscope. The drugs were injected subcutaneously into the scrotum, whence they diffused into the underlying (striated) cremaster muscle. An intravenous injection of colloidal HgS was also given, in order to facilitate the identification of leaks by means of visible tracer particles. After intervals varying from 1 minute to 57 days the animals were killed; the cremaster was fixed, embedded in methacrylate, and examined with the electron microscope. One to 12 minutes after the injection, the blood vessels of the smallest caliber (3 to 5 micra as measured on electron micrographs) appeared intact. Numerous endothelial openings were present in blood vessels with a diameter of 7 to 8 micra or more. These gaps were 0.1 to 0.8 micra in width; portions of intercellular junctions were often present in one or both of the margins. The underlying basement membrane was morphologically intact. An accumulation of tracer particles and chylomicra against the basement membrane indicated that the latter behaved as a filter, allowing fluid to escape but retaining and concentrating suspended particulate matter of the size used. Uptake of tracer particles by endothelial vesicles was minimal. Phagocytosis by endothelial cells became more prominent at 3 hours, but as a secondary occurrence; the pericytes were actively phagocytic at all stages. At the 3-hour stage no leaks were found. The changes induced by histamine and serotonin were indistinguishable, except that the latter was more potent on a mole-to-mole basis. In control animals only small accumulations of tracer particles were found in the wall of a number of blood vessels. With regard to the pathogenesis of the endothelial leaks, the electron microscopic findings suggested that the endothelial cells become partially disconnected along the intercellular junctions. Supporting evidence was provided at the level of the light microscope, by demonstrating—in the same preparation—the leaks with appropriate tracer particles1, and the intercellular junctions by the silver nitrate method. The lipid nature of the chylomicron deposits observed in electron micrographs was also confirmed at the level of the light microscope, using cremasters fixed in formalin and stained in toto with sudan red.

scholarly journals Mesangial cells organize the glomerular capillaries by adhering to the G domain of laminin α5 in the glomerular basement membrane

2003 ◽  
Vol 161 (1) ◽  
pp. 187-196 ◽  
Author(s):  
Yamato Kikkawa ◽  
Ismo Virtanen ◽  
Jeffrey H. Miner
Keyword(s):  
Cell Adhesion ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Basement Membranes ◽  
Domain Specific ◽  
Integrin Α3β1 ◽  
Glomerular Capillaries

In developing glomeruli, laminin α5 replaces laminin α1 in the glomerular basement membrane (GBM) at the capillary loop stage, a transition required for glomerulogenesis. To investigate domain-specific functions of laminin α5 during glomerulogenesis, we produced transgenic mice that express a chimeric laminin composed of laminin α5 domains VI through I fused to the human laminin α1 globular (G) domain, designated Mr51. Transgene-derived protein accumulated in many basement membranes, including the developing GBM. When bred onto the Lama5 −/− background, Mr51 supported GBM formation, preventing the breakdown that normally occurs in Lama5 −/− glomeruli. In addition, podocytes exhibited their typical arrangement in a single cell layer epithelium adjacent to the GBM, but convolution of glomerular capillaries did not occur. Instead, capillaries were distended and exhibited a ballooned appearance, a phenotype similar to that observed in the total absence of mesangial cells. However, here the phenotype could be attributed to the lack of mesangial cell adhesion to the GBM, suggesting that the G domain of laminin α5 is essential for this adhesion. Analysis of an additional chimeric transgene allowed us to narrow the region of the α5 G domain essential for mesangial cell adhesion to α5LG3-5. Finally, in vitro studies showed that integrin α3β1 and the Lutheran glycoprotein mediate adhesion of mesangial cells to laminin α5. Our results elucidate a mechanism whereby mesangial cells organize the glomerular capillaries by adhering to the G domain of laminin α5 in the GBM.

scholarly journals Antibodies to basement membrane heparan sulfate proteoglycans bind to the laminae rarae of the glomerular basement membrane (GBM) and induce subepithelial GBM thickening.

1986 ◽  
Vol 163 (5) ◽  
pp. 1064-1084 ◽  
Author(s):  
A Miettinen ◽  
J L Stow ◽  
S Mentone ◽  
M G Farquhar
Keyword(s):  
Basement Membrane ◽  
Core Protein ◽  
Basement Membranes ◽  
Immunoperoxidase Staining ◽  
Dependent Manner ◽  
The Core ◽  
Core Proteins ◽  
Rabbit Igg ◽  
Gbm Thickening ◽  
Glomerular Capillaries

Antibodies specific for the core protein of basement membrane HSPG (Mr = 130,000) were administered to rats by intravenous injection, and the pathologic consequences on the kidney were determined at 3 min to 2 mo postinjection. Controls were given antibodies against gp330 (the pathogenic antigen of Heymann nephritis) or normal rabbit IgG. The injected anti-HSPG(GBM) IgG disappeared rapidly (by 1 d) from the circulation. The urinary excretion of albumin increased in a dose-dependent manner during the first 4 d, was increased 10-fold at 1-2 mo, but remained moderate (mean = 12 mg/24 h). By immunofluorescence the anti-HSPG(GBM) was seen to bind rapidly (by 3 min) to all glomerular capillaries, and by immunoperoxidase staining the anti-HSPG was seen to bind exclusively to the laminae rarae of the GBM where it remained during the entire 2-mo observation period. C3 was detected in glomeruli immediately after the injection (3 min), where it bound exclusively to the lamina rara interna; the amount of C3 bound increased up to 2 h but decreased rapidly thereafter, and was not detectable after 4 d. Mononuclear and PMN leukocytes accumulated in glomerular capillaries, adhered to the capillary wall, and extended pseudopodia through the endothelial fenestrae to contact in the LRI of the GBM where the immune deposits and C3 were located. At 1 wk postinjection, staining for C3 reappeared in the glomeruli of some of the rats, and by this time most of the rats, including controls injected with normal rabbit IgG, had circulating anti-rabbit IgG (by ELISA) and linear deposits of rat IgG along the GBM (by immunofluorescence). Beginning at 9 d, there was progressive subepithelial thickening of the GBM which in some places was two to three times its normal width. This thickening was due to the laying down of a new layer of basement membrane-like material on the epithelial side of the GBM, which gradually displaced the old basement membrane layers toward the endothelium. The results show that the core proteins of this population of basement membrane HSPG (Mr = 130,000), which are ubiquitous components of basement membranes, are exposed to the circulation and can bind anti-HSPG(GBM) IgG in the laminae rarae of the GBM. Binding of these antibodies to the GBM leads to changes (C3 deposition, leukocyte adherence, moderate proteinuria, GBM thickening) considered typical of the acute phase of anti-GBM glomerulonephritis. Antibody binding interferes with the normal turnover of the GBM, presumably by affecting the biosynthesis and/or degradation of basement membrane components.

scholarly journals Human microvascular endothelial cells use beta 1 and beta 3 integrin receptor complexes to attach to laminin.

1990 ◽  
Vol 111 (3) ◽  
pp. 1233-1243 ◽  
Author(s):  
R H Kramer ◽  
Y F Cheng ◽  
R Clyman
Keyword(s):  
Endothelial Cells ◽  
Monoclonal Antibodies ◽  
Basement Membrane ◽  
Basement Membranes ◽  
Microvascular Endothelial Cells ◽  
Integrin Receptor ◽  
Receptor Complexes ◽  
Vascular Basement Membrane ◽  
Microvascular Endothelial ◽  
Alpha V Beta 3

Microvascular endothelial cells (MEC) use a set of surface receptors to adhere not only to the vascular basement membrane but, during angiogenic stimulation, to the interstitium. We examined how cultured human MEC interact with laminin-rich basement membranes. By using a panel of monoclonal antibodies, we found that MEC cells express a number of integrin-related receptor complexes, including alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha 6 beta 1, alpha V beta 3. Attachment to laminin, a major adhesive protein in basement membranes, was studied in detail. Blocking monoclonal antibodies specific to different integrin receptor complexes showed that the alpha 6 beta 1 complex was important for MEC adhesion to laminin. In addition, blocking antibody also implicated the vitronectin receptor (alpha V beta 3) in laminin adhesion. We used ligand affinity chromatography of detergent-solubilized receptor complexes to further define receptor specificity. On laminin-Sepharose columns, we identified several integrin receptor complexes whose affinity for the ligand was dependent on the type of divalent cation present. Several beta 1 complexes, including alpha 1 beta 1, alpha 2 beta 1, and alpha 6 beta 1 bound strongly to laminin. In agreement with the antibody blocking experiments, alpha V beta 3 was found to bind well to laminin. However, unlike binding to its other ligands (e.g., vitronectin, fibrinogen, von Willebrand factor), alpha V beta 3 interaction with laminin did not appear to be Arg-Gly-Asp (RGD) sensitive. Finally, immunofluorescent staining demonstrated both beta 1 and beta 3 complexes in vinculin-positive focal adhesion plaques on the basal surface of MEC adhering to laminin-coated substrates. The results indicate that both these subfamilies of integrin heterodimers are involved in promoting MEC adhesion to laminin and the vascular basement membrane.

scholarly journals Loss of laminin epitopes during glomerular basement membrane assembly in developing mouse kidneys.

1992 ◽  
Vol 40 (12) ◽  
pp. 1943-1953 ◽  
Author(s):  
D R Abrahamson ◽  
P L St John
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Horseradish Peroxidase ◽  
Glomerular Basement Membrane ◽  
Basement Membranes ◽  
Proteolytic Processing ◽  
Newborn Mouse ◽  
Capillary Loop ◽  
Loop Expansion ◽  
Initial Assembly

Kidney glomerular basement membranes (GMBs) originate in development from fusion of a dual basement membrane between endothelial cells and primitive epithelial podocytes. After fusion, segments of newly synthesized matrix, derived primarily from podocytes, appear as subepithelial outpockets and are spliced into GBMs during glomerular capillary loop expansion. To investigate GBM assembly further, we examined newborn mouse kidneys with monoclonal rat anti-mouse laminin IgGs (MAb) conjugated to horseradish peroxidase (HRP). In adults, these MAb strongly label glomerular mesangial matrices but bind only weakly or not at all to mature GBMs. In contrast, anti-laminin MAb intensely bound newborn mouse GBMs undergoing initial assembly. After intraperitoneal injection of MAb-HRP into neonates, dense binding occurred across both subendothelial and subepithelial pre-fusion GMBs as well as forming mesangial matrices. Considerably less MAb binding was seen, however, in post-fusion GBMs from more mature glomeruli in the same section, although mesangial matrices remained positive. In addition, new subepithelial segments in areas of splicing were negative. These results conflict with those obtained previously with injections of polyclonal anti-laminin IgGs into newborns or adults, which result in complete labeling of all GBMs. Although epitope masking cannot be completely excluded, we believe that decreased MAb binding to developing GBM reflects actual epitope loss. This loss could occur by laminin isoform substitution, conformational change, and/or proteolytic processing during GBM assembly.

scholarly journals Development and ultrastructure of glomerular capillaries in human foetus

2008 ◽  
Vol 136 (Suppl. 4) ◽  
pp. 316-322 ◽  
Author(s):  
Marija Dakovic-Bjelakovic ◽  
Vojin Savic ◽  
Slobodan Vlajkovic ◽  
Tanja Dzopalic
Keyword(s):  
Endothelial Cells ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
The Body ◽  
Developmental Changes ◽  
Human Foetus ◽  
Endothelial Basement Membrane ◽  
Cytoplasmic Processes ◽  
Endothelial Precursors ◽  
Glomerular Capillaries

Glomerulus is an important filtrating apparatus in the body. Three types of cells - endothelial, mesangial and visceral epithelial cells can be identified in the capillary tuft. Glomeruli develop during nephrogenesis which starts in the 8th week and ends between the 32nd and 36th week of gestation. The nephron develops through stages described as the vesicle, the comma-shaped, S-shaped with the developing glomerulus and the mature glomerulus. Glomerular differentiation involves the expansion of the original capillary component into the plexus that consists of 6-8 loops and the migration of podocytes that are arranged around these glomerular capillaries. Glomerular capillary differentiation represents a set of developmental changes of the glomerular endothelial and epithelial cells. The active differentiation of glomerular capillaries starts in the hemisphere of an inferior arm of S-shaped bodies. Endothelial precursors unite into precapillaries devoid of lumen. Further differentiation includes the flattening of endothelial cells on the basement membrane, the loss of superfluous cells, the development of lumen and the formation of fenestrae. The glomerular basement membrane is differentiated by the fusion of epithelial and endothelial basement membrane. The differentiation of visceral epithelial cells includes the development of cytoplasmic processes and the flattening of cell bodies. Primary cytoplasmic processes are formed from the podocyte bodies and develop secondary and tertiary processes or foot processes. Foot processes from one podocyte interdigitate with foot processes from other podocytes. In the developing glomeruli, there is a difference in the level of differentiation of visceral epithelial cells. Cells with differentiated foot processes and cells with no cytoplasmic processes are observed within the same glomerulus.

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