1
|
Ilatovskaya DV, Palygin O, Levchenko V, Staruschenko A. Single-channel Analysis and Calcium Imaging in the Podocytes of the Freshly Isolated Glomeruli. J Vis Exp 2015:e52850. [PMID: 26167808 DOI: 10.3791/52850] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Podocytes (renal glomerular epithelial cells) are known to regulate glomerular permeability and maintain glomerular structure; a key role for these cells in the pathogenesis of various renal diseases has been established since podocyte injury leads to proteinuria and foot process effacement. It was previously reported that various endogenous agents may cause a dramatic overload in intracellular Ca(2+) concentration in podocytes, presumably leading to albuminuria, and this likely occurs via calcium-conducting ion channels. Therefore, it appeared important to study calcium handling in the podocytes both under normal conditions and in various pathological states. However, available experimental approaches have remained somewhat limited to cultured and transfected cells. Although they represent a good basic model for such studies, they are essentially extracted from the native environment of the glomerulus. Here we describe the methodology of studying podocytes as a part of the freshly isolated whole glomerulus. This preparation retains the functional potential of the podocytes, which are still attached to the capillaries; therefore, podocytes remain in the environment that conserves the major parts of the glomeruli filtration apparatus. The present manuscript elaborates on two experimental approaches that allow 1) real-time detection of calcium concentration changes with the help of ratiometric confocal fluorescence microscopy, and 2) the recording of the single ion channels activity in the podocytes of the freshly isolated glomeruli. These methodologies utilize the advantages of the native environment of the glomerulus that enable researchers to resolve acute changes in the intracellular calcium handling in response to applications of various agents, measure basal concentration of calcium within the cells (for instance, to evaluate disease progression), and assess and manipulate calcium conductance at the level of single ion channels.
Collapse
Affiliation(s)
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin
| | | | | |
Collapse
|
2
|
Vuchkova J, Comper WD. Inhibition of the metabolic degradation of filtered albumin is a major determinant of albuminuria. PLoS One 2015; 10:e0127853. [PMID: 26010895 PMCID: PMC4444184 DOI: 10.1371/journal.pone.0127853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 04/20/2015] [Indexed: 02/03/2023] Open
Abstract
Inhibition of the degradation of filtered albumin has been proposed as a widespread, benign form of albuminuria. There have however been recent reports that radiolabeled albumin fragments in urine are not exclusively generated by the kidney and that in albuminuric states albumin fragment excretion is not inhibited. In order to resolve this controversy we have examined the fate of various radiolabeled low molecular weight protein degradation products (LMWDPs) introduced into the circulation in rats. The influence of puromycin aminonucleoside nephrosis on the processing and excretion of LMWDPs is also examined. The status and destinies of radiolabeled LMWDPs in the circulation are complex. A major finding is that LMWDPs are rapidly eliminated from the circulation (>97% in 2 h) but only small quantities (<4%) are excreted in urine. Small (<4%) but significant amounts of LMWDPs may have prolonged elimination (>24 h) due to binding to high molecular weight components in the circulation. If LMWDPs of albumin seen in the urine are produced by extra renal degradation it would require the degradation to far exceed the known catabolic rate of albumin. Alternatively, if an estimate of the role of extra renal degradation is made from the limit of detection of LMWDPs in plasma, then extra renal degradation would only contribute <1% of the total excretion of LMWDPs of albumin. We confirm that the degradation process for albumin is specifically associated with filtered albumin and this is inhibited in albuminuric states. This inhibition is also the primary determinant of the massive change in intact albuminuria in nephrotic states.
Collapse
Affiliation(s)
- Julijana Vuchkova
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Wayne D. Comper
- SalAqua Diagnostics Inc., Suite 258, 888c 8 Ave, New York, New York, 10019, United States of America
- * E-mail:
| |
Collapse
|
3
|
|
4
|
Kanwar YS, Venkatachalam MA. Ultrastructure of Glomerulus and Juxtaglomerular Apparatus. Compr Physiol 2011. [DOI: 10.1002/cphy.cp080101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
5
|
Abstract
Podocalyxin, a sialomucin most closely related to CD34 and endoglycan, is expressed by kidney podocytes, hematopoietic progenitors, vascular endothelia, and a subset of neurons; aberrant expression has recently been implicated in a range of cancers. Through interactions with several intracellular proteins and at least one extracellular ligand, podocalyxin regulates both adhesion and cell morphology. In the developing kidney, podocalyxin plays an essential role in the formation and maintenance of podocyte foot processes, and its absence results in perinatal lethality. Podocalyxin expression in the hematopoietic system correlates with cell migration and the seeding of new hematopoietic tissues. In addition, it is abnormally expressed in subsets of breast, prostate, liver, pancreatic, and kidney cancer as well as leukemia. Strikingly, it is often associated with the most aggressive cases, and it is likely involved in metastasis. Thus, a thorough investigation of the normal activities of podocalyxin may facilitate the development of new cancer treatment strategies.
Collapse
Affiliation(s)
- Julie S Nielsen
- The Biomedical Research Centre, Vancouver, British Columbia, Canada
| | | |
Collapse
|
6
|
Tojo A, Onozato ML, Kitiyakara C, Kinugasa S, Fukuda S, Sakai T, Fujita T. Glomerular albumin filtration through podocyte cell body in puromycin aminonucleoside nephrotic rat. Med Mol Morphol 2008; 41:92-8. [PMID: 18592163 DOI: 10.1007/s00795-008-0397-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 02/26/2008] [Indexed: 11/27/2022]
Abstract
It is an a priori concept that protein molecules including albumin are filtrated through the slit membrane between the foot processes of podocytes. However, foot processes are effaced and the number of slit membranes is reduced in nephrotic syndrome, suggesting another pathway of albumin filtration through the foot process cell body. Thus, we investigated the pathway of gold-and fluorescein isothiocyanate (FITC)-labeled albumin filtration in the puromycin aminonucleoside (PAN) model of nephrotic syndrome in the rat. PAN rats at day 7 with established nephrotic proteinuria were injected with 8-nm gold-labeled albumin and FITC-labeled albumin through the jugular vein followed by kidney fixation at 10 or 30 min. Goldlabeled albumin was accumulated in the paramesangial area and in the endosomes of glomerular endothelial cells of both control and PAN rats by electron microscopy. On the other hand, FITC-labeled albumin was detected between foot processes in the control but more in the podocyte cell body in the PAN rat. In conclusion, albumin will be filtrated through the decreased numbers of slit diaphragms; however, albumin can be also taken up in the podocyte, the mesangium, and the glomerular endothelium, suggesting that there might be other routes of glomerular albumin clearance in nephrotic syndrome.
Collapse
Affiliation(s)
- Akihiro Tojo
- Division of Nephrology and Endocrinology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
| | | | | | | | | | | | | |
Collapse
|
7
|
Yatsu T, Aoki M, Tanaka A. Effect of zelandopam, a dopamine D1-like receptor agonist, in puromycin aminonucleoside nephrosis rats. Eur J Pharmacol 2005; 510:121-6. [PMID: 15740732 DOI: 10.1016/j.ejphar.2005.01.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 01/11/2005] [Accepted: 01/13/2005] [Indexed: 01/08/2023]
Abstract
The present experiment was designed to investigate the role of peripheral dopamine D1-like receptors and to evaluate the prophylactic effect of zelandopam, a dopamine D1-like receptor agonist, on puromycin aminonucleoside (PA)-induced nephrosis in rats. Rats were divided into six groups (n=10 per group): 0.9% saline-injected rats (control); PA-injected rats (PAN); PA-injected rats treated with the selective dopamine D1-like receptor agonist zelandopam (30, 100, 300 mg/kg p.o. twice a day); PA-injected rats treated with prednisolone (1 mg/kg p.o. once a day). Nephrosis was induced in rats with a single intravenous injection of PA at a dose of 50 mg/kg. The effects of zelandopam and prednisolone in PA nephrosis rats were evaluated before injection of PA and at 7 and 14 days after injection. PA-induced nephrosis was characterized by an increase in urinary protein excretion (proteinuria) and plasma total cholesterol. Zelandopam dose-dependently attenuated the increase in proteinuria and total cholesterol. Prednisolone significantly attenuated the increase in proteinuria and total cholesterol and resulted in a significant decrease in body weight. The present study demonstrates for the first time that zelandopam, a selective dopamine D1-like receptor agonist, is effective in blunting the development of PA-induced nephrosis, and that the effects of zelandopam are dose dependent.
Collapse
Affiliation(s)
- Takeyuki Yatsu
- Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan.
| | | | | |
Collapse
|
8
|
Besse-Eschmann V, Klisic J, Nief V, Le Hir M, Kaissling B, Ambühl PM. Regulation of the proximal tubular sodium/proton exchanger NHE3 in rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. J Am Soc Nephrol 2002; 13:2199-206. [PMID: 12191963 DOI: 10.1097/01.asn.0000028839.52271.df] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Excessive proteinuria due to loss of glomerular permselectivity in nephrotic syndrome can cause disturbances in renal salt and water handling with edema formation. Apart from oncotic and hydrostatic mechanisms associated with hypoalbuminemia, primary derangements in renal tubular sodium transport may contribute to the pathogenesis of nephrotic edema. Whereas there is evidence for an increase of cortical collecting duct sodium reabsorption in nephrotic rats, it remains controversial whether proximal tubule sodium transport may also be activated in this condition. The regulation of the cortical Na/H exchanger NHE3, the main pathway for Na reabsorption in the proximal tubule (PT), was investigated in rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. PAN rats developed reduced GFR, severe proteinuria, and sodium retention within 3 d. After 10 d, immunoblots of brush border vesicles revealed a decreased abundance of NHE3 in nephrotic animals. However, the Na/H antiporter activity in the same vesicle preparations was not significantly altered. Antiporter activity normalized for NHE3 protein was increased by 88% in nephrotic animals (P = 0.025). Immunohistochemistry with the same polyclonal antibody as for immunoblots revealed a decrease of NHE3 abundance in PT. In contrast, immunoreactivity for the monoclonal antibody 2B9, which specifically recognizes the non-megalin-associated, transport-competent pool of NHE3, was higher in PAN-treated rats than in controls. In conclusion, increased sodium reabsorption might be associated with a shift of NHE3 from an inactive pool to an active pool, thus contributing to sodium retention in a state of proteinuria.
Collapse
|
9
|
Affiliation(s)
- Luis I Juncos
- IPEM-Gambro Healthcare, IV Departmnent of Medicine, National University of Cordoba, Colon 4154, Cordoba 5003, Argentina.
| |
Collapse
|
10
|
Hjalmarsson C, Ohlson M, Haraldsson B. Puromycin aminonucleoside damages the glomerular size barrier with minimal effects on charge density. Am J Physiol Renal Physiol 2001; 281:F503-12. [PMID: 11502599 DOI: 10.1152/ajprenal.2001.281.3.f503] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Puromycin aminonucleoside (PAN) has been suggested to reduce glomerular charge density, to create large glomerular "leaks," or not to affect the glomerular barrier. Therefore, we analyzed glomerular charge and size selectivity in vivo and in isolated kidneys perfused at 8 degrees C (cIPK) in control and PAN-treated rats. The fractional clearances (theta) for albumin and Ficoll of similar hydrodynamic size were 0.0017 +/- 0.0004 and 0.15 +/- 0.02, respectively, in control cIPKs. Two-pore analysis gave similar results in vivo and in vitro, with small- and large-pore radii of 47-52 and 85-105 A, respectively, in controls. Puromycin increased the number of large pores 40-50 times, the total pore area over diffusion distance decreased by a factor of 25-30, and the small-pore radius increased by 33% (P < 0.001 for all comparisons of size selectivity and theta). The effect of PAN was less dramatic on the estimated wall charge density, which was 73% of that of controls. We conclude that puromycin effectively destroys the glomerular size barrier with minimal effects on charge density.
Collapse
Affiliation(s)
- C Hjalmarsson
- Department of Physiology, Göteborg University, SE-405 30 Göteborg, Sweden
| | | | | |
Collapse
|
11
|
Sanwal V, Pandya M, Bhaskaran M, Franki N, Reddy K, Ding G, Kapasi A, Valderrama E, Singhal PC. Puromycin aminonucleoside induces glomerular epithelial cell apoptosis. Exp Mol Pathol 2001; 70:54-64. [PMID: 11170791 DOI: 10.1006/exmp.2000.2345] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glomerular epithelial cell (GEC) injury has been considered to play an important role in puromycin aminonucleoside (PAN)-induced nephrosis. We studied the effect of PAN on rat as well as human GEC apoptosis. Morphogic evaluation of GEC apoptosis and necrosis was carried out by staining with H-33342 and propidium iodide. GEC apoptosis was further confirmed by DNA fragmentation assay (by both agarose gel electrophoresis and end-labeling). To determine the dose- and time-response effect of PAN, GECs were treated with variable concentrations of PAN (10 to 500 microg/ml) for variable time periods (6 to 48 h). To determine the role of gene synthesis, we studied the effect of actinomycin D (a transcriptional inhibitor) on PAN-induced GEC apoptosis. To determine the role of free radicals, we evaluated the effect of superoxide dismutase (SOD), dimethylthiourea (DMTU), and catalase on PAN-induced GEC apoptosis. PAN induced GEC apoptosis in a dose- and time-dependent manner. PAN at a high concentration (PAN, 100 microg/ml) also induced a moderate degree of GEC necrosis. In DNA fragmentation assays PAN-treated GECs showed the classic ladder pattern. PAN-induced GEC apoptosis was partly attenuated with free radical scavengers, such as SOD, DMTU, and catalase. In addition, actinomycin D attenuated PAN-induced GEC apoptosis. PAN induces GEC apoptosis, which may be mediated through the generation of reactive oxygen species.
Collapse
Affiliation(s)
- V Sanwal
- Molecular Biology and Experimental Pathology Section, Long Island Jewish Medical Center and North Shore University Hospital, New York, New York 11040, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Löwenborg EK, Jaremko G, Berg UB. Glomerular function and morphology in puromycin aminonucleoside nephropathy in rats. Nephrol Dial Transplant 2000; 15:1547-55. [PMID: 11007821 DOI: 10.1093/ndt/15.10.1547] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The most characteristic manifestation of minimal-change nephropathy is podocyte cell process broadening. In a previous study in children from our unit, we found an inverse correlation between foot process width, glomerular filtration rate (GFR), and filtration fraction. The aim of the present study was to determine whether this relationship also existed in the puromycin aminonucleoside (PAN) experimental model. METHODS Sixteen Munich-Wistar-Frömter male rats initially weighing median 247 g (range 171-286) were used. Four rats served as controls. The other 12 rats were divided into three groups receiving daily subcutaneous injections of 1, 1.67, and 2.5 mg PAN/100 g body weight respectively, for 6 days. GFR was determined by clearance of inulin and the fractional urine albumin excretion was measured. Standard stereological methods were used to estimate the glomerular volume, the mean foot process width and the length density of slit pores. RESULTS GFR decreased with increasing PAN doses. The glomerular volume was increased in the group receiving the lowest PAN dose, while it was decreased in the group with the highest PAN dose, compared with controls. The fractional albumin excretion and the foot process width increased and the total slit pore length decreased with increasing doses of PAN. GFR correlated directly with the glomerular volume as did the foot process width with the fractional albumin excretion. The foot process width correlated inversely with the glomerular volume as did the glomerular volume with the fractional albumin excretion, and GFR with foot process width. CONCLUSIONS The decreased GFR found in the nephrotic rats was inversely related to foot process width and directly related to glomerular volume, confirming our previous results in children in an early stage of the nephrotic syndrome.
Collapse
Affiliation(s)
- E K Löwenborg
- Department of Pediatrics, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden
| | | | | |
Collapse
|
13
|
Osicka TM, Hankin AR, Comper WD. Puromycin aminonucleoside nephrosis results in a marked increase in fractional clearance of albumin. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:F139-45. [PMID: 10409307 DOI: 10.1152/ajprenal.1999.277.1.f139] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Puromycin aminonucleoside nephrosis (PAN) results in a marked increase in the fractional clearance of albumin. The increase in the fractional clearance of [(3)H]albumin to approximately 0.045, as measured both in vivo and in the isolated perfused rat kidney (IPK) with PAN, occurs without an accompanying equivalent increase in glomerular capillary wall size selectivity as previously measured with dextrans. This is very similar to the marked increase in albuminuria seen with kidneys treated with inhibitors of endocytosis by the tubular epithelium, particularly lysine (T. M. Osicka, L. M. Pratt, and W. D. Comper. Nephrology 2: 199-212, 1996). The similarity is further established that, like in the presence of lysine, [(3)H]albumin excreted in urine from rats with PAN is essentially intact whereas, in both in vivo and IPK control experiments, excreted [(3)H]albumin is heavily degraded. The same observations have also been made for (3)H-labeled anionic horseradish peroxidase. These observations suggest that the significant albuminuria that occurs in PAN is primarily post-glomerular basement membrane in origin.
Collapse
Affiliation(s)
- T M Osicka
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia 3168
| | | | | |
Collapse
|
14
|
Osicka TM, Comper WD. Tubular inhibition destroys charge selectivity for anionic and neutral horseradish peroxidase. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1381:170-8. [PMID: 9685630 DOI: 10.1016/s0304-4165(98)00025-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The fractional clearance of [3H]anionic HRP and [3H]neutral HRP in the isolated perfused kidney as determined by radioactivity analysis was 0.0160+/-0.0028 (n=6) and 0.0388+/-0.0076 (n=8) respectively. The apparent charge selectivity for both the anionic and neutral forms of HRP observed was destroyed with the inclusion of the tubular uptake inhibitors, 150 mM lysine and 10 mM NH4Cl, in the perfusate. In the presence of 150 mM lysine, the clearances of [3H]anionic HRP and [3H]neutral HRP were 0.0645+/-0.0110 (n=4) and 0. 0784+/-0.0120 (n=4) respectively, and 0.0564+/-0.0035 (n=4) and 0. 0694+/-0.0054 (n=4) respectively in the presence of 10 mM NH4Cl. The clearance for both the anionic and neutral HRP probes in these tubular uptake inhibited systems fits precisely the size selective characteristics of the glomerular capillary wall as determined by transport probes calibrated for hydrodynamic size by size exclusion chromatography. The tubular uptake inhibitors were observed not to alter glomerular permselectivity as determined using polydisperse dextran fractions and the behaviour of neutral HRP. This study demonstrates that charge selectivity for differently charged proteins is not as great as originally thought and suggests that the clearance differences between anionic and neutral forms may be due to differential handling by the tubules.
Collapse
Affiliation(s)
- T M Osicka
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia
| | | |
Collapse
|
15
|
Nosaka K, Takahashi T, Nishi T, Imaki H, Suzuki T, Suzuki K, Kurokawa K, Endou H. An adenosine deaminase inhibitor prevents puromycin aminonucleoside nephrotoxicity. Free Radic Biol Med 1997; 22:597-605. [PMID: 9013123 DOI: 10.1016/s0891-5849(96)00349-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Puromycin aminonucleoside (PAN) toxicity was totally inhibited in the rat in vivo and in cultured glomerular epithelial cells (GECs) in vitro using the adenosine deaminase (ADA) inhibitor, 2'-deoxycoformycin (DCF). DCF completely inhibited ADA activity in glomeruli and protected against the development of PAN nephrosis; the 24-h urinary protein excretion of treated rats compared with controls (PAN rats) 9 days after PAN injection was 16 +/- 2 mg and 524 +/- 55 mg, respectively (p < .01). Morphological examination also demonstrated that the glomerular epithelial cells were protected against PAN-induced damage. Furthermore, when DCF was added to the first passage of GECs simultaneously with PAN, the adenosine triphosphate contents of remnant GECs on culture substrata increased in a dose-dependent manner, and PA toxicity was completely inhibited by 10(-4) M DCF. The order of ADA activity in glomeruli from various species was as follows: rat > monkey > guinea pig > dog > rabbit > mouse. High activity of ADA in the glomerulus was limited to species in which PAN induced nephrosis. Additionally, DCF increased glomerular cyclic AMP contents, resulting from enhanced adenosine accumulation in the pericellular space. These results indicate that the pathogenesis of PAN toxicity is closely related to adenosine metabolism and that ADA plays a key role in this model. Furthermore, we speculate that DCF contributes to the inhibition of reactive oxygen metabolites by decreasing the substrate of xanthine oxidase and/or increasing pericellular adenosine accumulation.
Collapse
Affiliation(s)
- K Nosaka
- First Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Inoue S, Bendayan M. High-resolution ultrastructural study of the rat glomerular basement membrane in aminonucleoside nephrosis. Ultrastruct Pathol 1996; 20:409-16. [PMID: 8883324 DOI: 10.3109/01913129609016343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the initial stages of aminonucleoside nephrosis, functional alterations in the glomerular basement membrane occur, as evidenced by the development of proteinuria. However, it has not been possible to observe important ultrastructural modifications at the level of the basement membrane, probably because the changes are taking place at the molecular level. In this study, by the use of high-resolution electron microscopy, an attempt was made to evaluate such changes in rat glomerular basement membrane during acute aminonucleoside nephrosis. As previously reported, in control animals the glomerular basement membrane is composed of a network of 4-nm-wide irregular anastomosing strands, referred to as "cords," which are known to contain a core filament of type IV collagen surrounded by a "sheath" of other components, such as laminin and heparan sulfate proteoglycan (HSPG). The most conspicuous ultrastructural alteration of the nephrotic glomerular basement membrane, recognizable only at high magnification, is that the cords were denuded leaving only the core filament through the loss of the sheath material. Thus, the cord network was transformed, with the progress of pathological conditions, into a network of fine filaments. On the other hand, abundance and distribution of HSPG molecules known to be present in the form of 4.5- to 5-nm-wide ribbon-like "double tracks," were found to be similar in control and nephrotic tissues. Since HSPG is one of the charge proteins of the basement membrane, the little changes observed for HSPG are difficult to interpret in view of reported decreases in basement membrane anionic sites in nephrosis. In conclusion, the glomerular basement membrane in aminonucleoside nephrosis loses its cord network components and replaces them with a more perforated network, which could be a cause for the increased permeability of this basement membrane.
Collapse
Affiliation(s)
- S Inoue
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec, Canada
| | | |
Collapse
|
17
|
|
18
|
Ting RH, Kristal B, Myers BD. The biophysical basis of hypofiltration in nephrotic humans with membranous nephropathy. Kidney Int 1994; 45:390-7. [PMID: 8164424 DOI: 10.1038/ki.1994.50] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Physiologic and morphologic techniques were used to elucidate the determinants of the glomerular filtration rate in 62 nephrotic patients with membranous nephropathy and 104 healthy controls. Renal plasma flow, glomerular filtration rate, afferent oncotic pressure and dextran sieving coefficients were determined. Mathematical models of glomerular filtration were then used to compute likely upper bounds for the ultrafiltration coefficient and pore area/length ratio (a measure of pore density). These upper bounds for each measure of intrinsic ultrafiltration capacity were both depressed by 75% in membranous nephropathy. A corresponding excess of ultrafiltration pressure (versus control), attributable solely to reduced intracapillary oncotic pressure was by 12 mm Hg. Glomerular morphometry revealed peripheral capillary filtration surface area to be enhanced in membranous nephropathy (3.27 x 10(5) vs. 2.03 x 10(5) micron2). However, there was a massive reduction in filtration slit frequency due to epithelial podocyte broadening (336 vs. 1204 slits/mm capillary length) as well as marked thickening of the glomerular basement membrane (1130 vs. 388 nm). We conclude that the latter two findings lower the ultrafiltration coefficient in membranous nephropathy by depressing the hydraulic permeability of the glomerular capillary wall. We propose that this abnormality is solely responsible for the hypofiltration observed in a majority of patients with this disease.
Collapse
Affiliation(s)
- R H Ting
- Department of Medicine, Stanford University School of Medicine, California
| | | | | |
Collapse
|
19
|
Guasch A, Deen WM, Myers BD. Charge selectivity of the glomerular filtration barrier in healthy and nephrotic humans. J Clin Invest 1993; 92:2274-82. [PMID: 8227342 PMCID: PMC288408 DOI: 10.1172/jci116831] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We used dextran sulfate (DS) to evaluate barrier charge selectivity in 11 nonproteinuric subjects and in 11 patients with the nephrotic syndrome due to either membranous nephropathy or minimal change nephropathy. The 3H-DS preparation spanned a molecular radius interval of 10-24 A and exhibited size-dependent protein binding in vitro. Urine and ultrafiltrates of plasma were separated by size into narrow fractions using gel permeation chromatography. The sieving coefficient (theta) for ultrafilterable DS of 15A radius averaged 0.68 +/- 0.03 in nonproteinuric vs. 0.95 +/- 0.05 in nephrotic subjects (P < 0.001). Uncharged dextrans of broad size distribution were used to evaluate barrier size-selectivity in separate groups of nonproteinuric subjects (n = 19) and nephrotic patients with either minimal change (n = 20) or membranous nephropathy (n = 27). The value of theta for an uncharged dextran of similarly small radius (approximately 18 A) was significantly larger than that observed for DS in nonproteinuric subjects, but was similar in nephrotic individuals. Further, impaired barrier size-selectivity, as assessed by the sieving profile for uncharged dextrans (18-60 A radius), failed to account fully for the observed level of albuminuria in almost half of the patients with either minimal change (9/20) or membranous nephropathy (12/27). Together these findings suggest that the human glomerular capillary wall normally provides an electrostatic barrier to filtration of negatively charged macromolecules such as albumin, and that impairment of this electrostatic barrier contributes to the magnitude of albuminuria in the nephrotic syndrome.
Collapse
Affiliation(s)
- A Guasch
- Nephrology Division, Stanford University Medical Center, California 94305
| | | | | |
Collapse
|
20
|
Whiteside CI, Cameron R, Munk S, Levy J. Podocytic cytoskeletal disaggregation and basement-membrane detachment in puromycin aminonucleoside nephrosis. THE AMERICAN JOURNAL OF PATHOLOGY 1993; 142:1641-53. [PMID: 8494056 PMCID: PMC1886918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Puromycin aminonucleoside--(PAN) treated rats develop acute nephrotic syndrome, mimicking human minimal lesion disease. In PAN nephrosis, podocyte detachment from the glomerular basement membrane (GBM) is the most likely cause of massive proteinuria in this model. To elucidate further the mechanisms of PAN-induced cellular dysfunction, new methods were employed to visualize podocyte cytoskeletal aggregation and to measure fibrillar attachment to the GBM. Adult Sprague-Dawley rats (n = 4/group) received a single tail-vein injection of PAN (75 mg/kg). On days 1, 2, 3, and 5 following injection, 24-hour urine collections were obtained for creatinine clearance, albuminuria, and total proteinuria. Then kidneys from each group were fixed by perfusion. Podocytic cytoskeleton was visualized by scanning electron microscopy. Subepithelial GBM staining and attachment fiber number, observed on digitized images of transmission electron micrographs, were quantitated with computer-based density analysis. A significant reduction in attachment fiber number in the GBM lamina rara externa occurred by day 5. On scanning electron micrographs, the secondary and tertiary podocytic processes were observed to be formed by highly aggregated cytoskeleton, which became partially disaggregated by day 3, was totally absent by day 5, and normalized by day 20. Immunogold staining revealed that actin and vinculin localized to the tertiary podocytic processes in the normal state were dispersed into the cell body following PAN. Podocyte cytoskeletal disaggregation precedes, and detachment from the GBM occurs simultaneously with, the onset of massive proteinuria in the PAN model.
Collapse
Affiliation(s)
- C I Whiteside
- Department of Medicine, University of Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
21
|
Abstract
Neither the initiating factors nor the proximate causes of injury that produce proteinuria in nephrotic syndrome have been clearly defined. Immune mechanisms have been postulated in minimal-change nephrotic syndrome (MCNS), focal segmental glomerular sclerosis (FSGS), and glomerular sclerosis associated with human immunodeficiency virus (HIV) infection. Circulating factors have been proposed in MCNS and FSGS, although no specific mediator has been identified. Prompt remission of proteinuria following steroid treatment and the presence of altered immune responsiveness in patients with MCNS have been used to support the participation of an immune mechanism in the pathogenesis of MCNS. Both FSGS and HIV-related nephropathy are usually steroid-resistant. Immune mechanisms are postulated in FSGS because of early recurrence after transplantation, and in HIV-related nephropathy because of the numerous associated immune abnormalities. Experimental models of nephrotic syndrome based on neutralization of glomerular charge, toxic injury to podocytes, injection of antibodies to glomerular components, or abnormalities in transgenic mice have been used to define mechanisms of glomerular injury. This review summarizes physiologic and immunologic abnormalities in MCNS, FSGS, and HIV-associated nephropathy and in several experimental models of nephrotic syndrome, and outlines the immunologic mechanisms and cellular reactions that may be responsible for glomerular dysfunction in these entities.
Collapse
Affiliation(s)
- V J Savin
- Department of Medicine, University of Kansas Medical Center, Kansas City 66160-7382
| |
Collapse
|
22
|
Chin TA, Templeton DM. Protective elevations of glutathione and metallothionein in cadmium-exposed mesangial cells. Toxicology 1993; 77:145-56. [PMID: 8442010 DOI: 10.1016/0300-483x(93)90145-i] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Exposure of cultured rat mesangial cells to CdCl2 caused a dose- and time-dependent increase in intracellular glutathione that was significant at 0.5 microM and maximal at 1 microM Cd2+. The effect depended on glutathione synthesis and was masked by inhibiting synthesis with buthionine sulfoximine. The cells responded to slightly higher concentrations of Cd with a marked decrease in DNA synthesis, and reversible depletion of glutathione enhanced this sensitivity. Pre-induction of the thiol-rich protein metallothionein with ZnCl2 afforded a degree of protection to the glutathione-depleted cells. We conclude that the Cd-dependent elevation of glutathione in these cells may be protective at concentrations of Cd that can arise during acute environmental and occupational exposures.
Collapse
Affiliation(s)
- T A Chin
- Department of Clinical Biochemistry, University of Toronto, Canada
| | | |
Collapse
|
23
|
Russo P, Gingras D, Bendayan M. Poly-L-lysine-gold probe for the detection of anionic sites in normal glomeruli and in idiopathic and experimentally-induced nephrosis. A comparative ultrastructural study. THE AMERICAN JOURNAL OF PATHOLOGY 1993; 142:261-71. [PMID: 8424459 PMCID: PMC1886853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Anionic sites play a key role in the charge selectivity of glomerular filtration as well as in the maintenance of the structural integrity of the visceral epithelium and podocytes. Alterations in these sites are believed to be a major factor underlying human idiopathic nephrosis and puromycin-nephrosis in the rat. The poly-L-lysine-gold complex was used for the ultrastructural detection of anionic sites in renal glomeruli of patients with idiopathic nephrosis as well as of rats with puromycin-induced nephrosis, allowing for study of the changes occurring in the anionic sites during nephrosis and for the comparison between human disease and this experimental model. In both normal human and rat controls, the probe was detected on epithelial and endothelial cell surfaces and on the glomerular basement membrane, mainly in both laminae rarae. In proteinuric rats, a decrease in labeling intensity was noted on podocyte membranes and in the lamina rara externa, with a corresponding increase in the more central areas of the glomerular basement membrane. These changes were not as evident in proteinuric humans. Furthermore, a reduction in labeling density was noted in the glomerular basement membrane of proteinuric animals, although this could not be substantiated in human tissues. Poly-L-lysine-gold is a useful probe for anionic sites in fixed tissues, and allows for comparison between human disease and its experimental counterpart.
Collapse
Affiliation(s)
- P Russo
- Département de Pathologie, Hôpital Ste-Justine, Montréal, Québec, Canada
| | | | | |
Collapse
|
24
|
Kurihara H, Anderson JM, Kerjaschki D, Farquhar MG. The altered glomerular filtration slits seen in puromycin aminonucleoside nephrosis and protamine sulfate-treated rats contain the tight junction protein ZO-1. THE AMERICAN JOURNAL OF PATHOLOGY 1992; 141:805-16. [PMID: 1415478 PMCID: PMC1886648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nephrosis induced in rats by puromycin aminonucleoside treatment (PAN) results in the apical displacement of the glomerular filtration slit membrane by newly formed, intercellular occluding-type junctions. Similar changes can also be induced by acute kidney perfusion with protamine sulfate (PS). We have investigated the molecular nature of these altered junctions using an antibody to ZO-1, a protein found exclusively in tight junctions. Immunoblotting demonstrates ZO-1, a 225-kd band, in glomerular extracts of normal, PAN-, and PS-treated rats. By immunofluorescence, ZO-1 was localized at the base of podocytes outlining the capillary loops of glomeruli from all three experimental groups. At the electron microscope level, using immunoperoxidase or immunogold labeling, ZO-1 was concentrated along the cytoplasmic surfaces of the slit diaphragms of normal rats. In PAN or PS rats, it was concentrated along both the newly formed occluding-type junctions and the remaining slit diaphragms. When podocalyxin (the major membrane sialoprotein of the podocyte) was similarly localized, it was found exclusively apical to the displaced slit membrane. Based on morphology and the presence of ZO-1, the altered junctions seen in PAN and PS rats appear to represent bona fide tight junctions. Their rapid (15-minute) induction in PS-treated rats suggests that on neutralization of the cell surface charge by polycation perfusion, discontinuous tight junctions form from a preexisting pool of junctional proteins. These findings raise the possibility that glomerular hydraulic conductivity may be regulated in part by regulating the relative patency and width of the filtration slits through focal tight junction assembly.
Collapse
Affiliation(s)
- H Kurihara
- Division of Cellular and Molecular Medicine, University of California, San Deigo, La Jolla 92093-0651
| | | | | | | |
Collapse
|
25
|
Abstract
Acute, usually reversible, renal failure has been observed in patients with normal or minimally altered glomeruli on renal biopsy. This review aims to examine the clinical features of acute renal failure in these patients and to evaluate factors that may contribute to the reduction in glomerular filtration rate (GFR). In an analysis of 79 cases affecting 75 patients reported in the English literature since 1966, with acute renal failure associated with minimal change disease or mild histopathological changes in glomeruli, the average age was 58 +/- 2 years (mean +/- 5 SEM), urine protein excretion 11.6 +/- 0.6 g/d, and serum albumin level 19 +/- 1 g/L (1.9 +/- 0.1 g/dL). Acute renal failure was documented an average of 29 +/- 5 days after onset of nephrotic syndrome, and persisted for 7 weeks in 62 episodes in the 58 patients in whom recovery of renal function occurred. Fourteen patients died of uremia or required chronic dialysis, and 3 were lost to follow-up. Although plasma volume depletion was sometimes cited as the cause of renal failure, objective signs of hypovolemia were not documented and most patients did not improve after treatment designed to correct volume deficits. In contrast, histopathological changes consistent with acute tubular necrosis (ATN) were observed in at least 60% of cases. Since the pathogenesis of acute renal failure in minimal change nephrotic syndrome is unknown, we evaluated hemodynamic determinants of GFR in patients with minimal change disease with normal or near-normal renal function, and in relevant animal models, to obtain insights into the effect of nephrotic syndrome on GFR. Although acute renal failure is uncommon, GFR is reduced concurrently with nephrotic syndrome in approximately 30% of children and adults. Absolute and effective blood volume and renal plasma flow are relatively well preserved. However, clinical and experimental observations suggest that the glomerular ultrafiltration coefficient may be reduced by as much as 50%. These findings, together with renal biopsy changes in cases with acute renal failure, suggest that severe reductions in GFR in some patients with minimal change nephrotic syndrome may result from an interaction between acute ischemic tissue injury and preexisting intrinsic renal abnormalities.
Collapse
Affiliation(s)
- J D Smith
- Renal Division, Yale University School of Medicine, New Haven, CT 06510
| | | |
Collapse
|
26
|
Rada JA, Carlson EC. Anionic site and immunogold quantitation of heparan sulfate proteoglycans in glomerular basement membranes of puromycin aminonucleoside nephrotic rats. Anat Rec (Hoboken) 1991; 231:35-47. [PMID: 1750710 DOI: 10.1002/ar.1092310106] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Renal glomerular basement membranes (GBMs) exhibit a charge-selective barrier, consisting of heparan sulfate proteoglycan (HSPG) that restricts the passage of anionic molecules into the urine. Previous efforts to localize the HSPG core protein within various layers of the GBM have been contradictory. Furthermore, attempts to correlate proteinuria in several disease states with a decrease in anionic sites of HSPG core protein have yielded conflicting results. When antibodies to HSPG from the EHS tumor matrix [anti-(EHS) HSPG] and GBMs [anti-(GBM) HSPG] were used together with immunogold to label renal tissues from puromycin aminonucleoside nephrotic (PAN) rats, immunolabeling results indicated that a portion of the protein core recognized by anti-(EHS) HSPG was significantly reduced, while immunolabeling with anti-(GBM) HSPG was only slightly reduced in early PAN. Anionic sites (stained with the cationic probe, polyethyleneimine) within the lamina rara externa of the GBM remained unaltered throughout the course of PAN.
Collapse
Affiliation(s)
- J A Rada
- Pittsburgh Eye and Ear Institute, Pennsylvania 15213
| | | |
Collapse
|
27
|
Meyer TW. The Proteinuric Phase of Diabetic Nephrology. Nephrology (Carlton) 1991. [DOI: 10.1007/978-3-662-35158-1_138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
28
|
Russo PA, Bendayan M. Distribution of endogenous albumin in the glomerular wall of proteinuric patients. THE AMERICAN JOURNAL OF PATHOLOGY 1990; 137:1481-90. [PMID: 2260634 PMCID: PMC1877730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glomerular proteinuria seems to be related, in part, to loss or impairment of the normal barrier function of the glomerular capillary wall. To investigate the functional properties of this barrier, endogenous albumin was revealed in the glomerular wall of proteinuric patients and compared with a nonproteinuric control by immunoelectron microscopy using the protein A-gold method. In the control biopsy, peaks of albumin accumulation were noted in the subendothelial area and in the inner portion of the lamina densa, with gradual tapering of the distribution toward the epithelial side of the basement membrane. The urinary space and epithelial cells were weakly labeled. In tissues from proteinuric patients, albumin was distributed throughout the entire width of the glomerular basement membrane, although the pattern of accumulation varied between patients. The urinary space showed significant labeling associated with some flocculent material. Mesangial areas were heavily labeled in tissues from both control and proteinuric patients. In the latter, lysozomes in glomerular and tubular epithelial cells also accumulated albumin, which is evidence of reabsorption. These results reveal the existence, in normal conditions, of a barrier located in the subendothelial area of the glomerular basement membrane, the loss of which, as in the idiopathic nephrotic syndrome, leads to diffuse distribution of albumin in the glomerular capillary wall.
Collapse
Affiliation(s)
- P A Russo
- Department of Pathology, Hôpital Ste-Justine, Côte Ste-Catherine, Montreál, Canada
| | | |
Collapse
|
29
|
Harris KP, Lefkowith JB, Klahr S, Schreiner GF. Essential fatty acid deficiency ameliorates acute renal dysfunction in the rat after the administration of the aminonucleoside of puromycin. J Clin Invest 1990; 86:1115-23. [PMID: 2212002 PMCID: PMC296840 DOI: 10.1172/jci114816] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The administration of the aminonucleoside of puromycin (PAN) to rats causes the nephrotic syndrome that is associated with an acute decline in renal function, and an interstitial infiltrate. We examined whether essential fatty acid deficiency (EFAD), which inhibits macrophage infiltration in glomerulonephritis, affects PAN-induced renal dysfunction. Both control and EFAD rats developed proteinuria that resolved over 28 d. After PAN administration, there was a prominent infiltration of macrophages in rats fed a normal diet. The infiltrate was prevented by the EFAD diet. The absence of a macrophage interstitial infiltrate was associated with a significantly higher Cin in the EFAD rats than in controls at 7 d (5.21 +/- 1.19 versus 0.39 +/- 0.08, P less than 0.002 ml/min/kg BW). In addition, CPAH fell to less than 10 ml/min/kg BW by day 7 in controls, but remained the same as normal in the EFAD. After administration of PAN to control rats, there was no increase in urinary thromboxane excretion or an increase in glomerular thromboxane production. Furthermore, the effect of EFAD could not be mimicked by the administration of a thromboxane synthase inhibitor. Irradiation-induced leukopenia in rats on a normal diet markedly improved glomerular filtration and renal blood flow in acutely nephrotic rats. EFAD prevents the interstitial cellular infiltrate and the renal ischemia associated with experimental nephrosis. The recruitment of mononuclear cells into the kidney following PAN directly contributes to the decline in renal function.
Collapse
Affiliation(s)
- K P Harris
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | | | | | | |
Collapse
|
30
|
Zamparo O, Comper WD. Model anionic polysaccharide matrices exhibit lower charge selectivity than is normally associated with kidney ultrafiltration. Biophys Chem 1990; 38:167-78. [PMID: 2085651 DOI: 10.1016/0301-4622(90)80052-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The influence of the anionic polysaccharide matrix (APM) of the glomerular basement membrane (GBM) on water transport and macromolecular transport charge selectivity has been studied in model systems which enable the analysis of the specific properties of the APM. Various APMs were studied including heparin and heparin-like polysaccharides, chondroitin sulfate and dextran sulfate. Upper estimates of the APM concentration in the GBM were obtained by relating measurements of the specific hydraulic conductivity of the heparin-like polysaccharides to measurements of single nephron glomerular filtration rate. This gave values of 40-45 mg ml-1 of polysaccharide, which was then used to analyse factors contributing to macromolecular charge selectivity. Transport analysis of the test dextran probes, used for previous in vivo clearance studies, in APMs demonstrated that there were no differential charge effects at APM concentrations in the range predicted above in the GBM. This was also found to be the case for the partitioning of anionic test probes at the APM-solution interface as measured directly using frontal gel chromatography and through thermodynamic analysis of sedimentation and diffusion data. These studies demonstrated that previous biophysical interpretations of glomerular charge selectivity have severely overestimated the partitioning effect due to the electrostatic effects of polyion-polyion interaction.
Collapse
Affiliation(s)
- O Zamparo
- Department of Biochemistry, Monash University, Clayton, Vic., Australia
| | | |
Collapse
|
31
|
Trachtman H, Del Pizzo R, Valderrama E, Gauthier B. The renal functional and structural consequences of corticosteroid and angiotensin-converting enzyme inhibitor therapy in chronic puromycin aminonucleoside nephropathy. Pediatr Nephrol 1990; 4:501-4. [PMID: 2242316 DOI: 10.1007/bf00869832] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Glomerular diseases are characterized by increased urinary protein excretion. Treatment of this abnormality frequently involves administration of corticosteroids and angiotensin-converting enzyme inhibitors. There has been much recent interest in the potential impact of these drugs on progressive renal dysfunction, since they have opposing effects on intraglomerular hemodynamics. Therefore, we investigated the effect of methylprednisolone or captopril treatment on animals with chronic puromycin aminonucleoside nephropathy. In rats given a single injection of puromycin aminonucleoside, 15 mg/100 g body weight, both methylprednisolone and captopril significantly reduced proteinuria at 6 months [83 +/- 14 untreated (n = 7), 34 +/- 6 with methylprednisolone (n = 8), and 6 +/- 1 mg/24 h with captopril (n = 5), P less than 0.001]. Segmental glomerulosclerosis occurred with equal frequency in the untreated (7.8 +/- 2.3%) and methylprednisolone-treated rats (5.0 +/- 1.11%), but was significantly reduced by the administration of captopril (1.0 +/- 0.5%, P less than 0.001). We conclude that in chronic puromycin aminonucleoside nephropathy, treatment with corticosteroids reduces proteinuria without increasing the incidence of segmental glomerulosclerosis. Therapy with an angiotensin-converting enzyme inhibitor substantially decreases proteinuria and lessens the severity of glomerular scarring.
Collapse
Affiliation(s)
- H Trachtman
- Department of Pediatrics (Division of Nephrology), Schneider Children'sHospital, Albert Einstein College of Medicine, New Hyde Park, NY 11042
| | | | | | | |
Collapse
|
32
|
Bertram JF, Messina A, Ryan GB. In vitro effects of puromycin aminonucleoside on the ultrastructure of rat glomerular podocytes. Cell Tissue Res 1990; 260:555-63. [PMID: 2372813 DOI: 10.1007/bf00297236] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Puromycin aminonucleoside (PAN)-induced nephrosis in rats provides a model for studying the pathogenesis of severe proteinuric conditions, such as minimal change disease. The present study used scanning (SEM) and transmission (TEM) electron microscopy to investigate the in vitro effects of PAN on rat glomerular podocytes. Slices of rat kidney were incubated for up to 3 days in Medium 199 with Hanks' salts (control) or in medium with PAN. Semiquantitative SEM analysis of glomeruli on the upper surface of kidney slices indicated that incubation with PAN (100 micrograms/ml and 500 micrograms/ml) decreased the number of microvilli on podocyte cell bodies (days 1, 2 and 3), increased the number of glomeruli showing flattening of podocyte cell bodies and major processes (days 2 and 3), and increased the number of glomeruli showing surface membrane blebbing on podocyte foot processes (day 3) (p less than 0.001 in all cases). TEM morphometry revealed that incubation with 500 micrograms/ml PAN retarded significantly (p less than 0.001 at days 2 and 3) the loss of podocyte foot processes observed in control cultures. Whilst the SEM changes to podocyte ultrastructure largely mimic those seen in PAN nephrosis in vivo, the retardation of foot process loss runs counter to the major TEM change observed in vivo.
Collapse
Affiliation(s)
- J F Bertram
- Department of Anatomy, University of Melbourne, Parkville, Victoria, Australia
| | | | | |
Collapse
|
33
|
Remuzzi A, Puntorieri S, Battaglia C, Bertani T, Remuzzi G. Angiotensin converting enzyme inhibition ameliorates glomerular filtration of macromolecules and water and lessens glomerular injury in the rat. J Clin Invest 1990; 85:541-9. [PMID: 1688888 PMCID: PMC296456 DOI: 10.1172/jci114470] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The effect of enalapril on glomerular hemodynamics and permselectivity and on subsequent sclerosis was studied in male MWF/Ztm rats which spontaneously develop proteinuria and glomerular structural damage. Untreated group 1 and enalapril-treated group 2 (50 mg/liter, in the drinking water) underwent micropuncture studies after 2 mo of observation. After the same period of treatment, group 3 (untreated) and group 4 (enalapril treated) were used for determination of whole-kidney function and neutral dextran clearances. Group 5 (untreated) and group 6 (enalapril treated) were followed for an additional 4 mo and used for kidney function and morphological studies. Enalapril significantly lowered systolic blood pressure, which was elevated in untreated groups, and significantly reduced proteinuria (295 +/- 64 vs. 128 +/- 24 mg/24 h by the end of the study). Despite the reduced renal perfusion pressure, whole-kidney glomerular filtration rate was higher in enalapril-treated than in untreated rats (0.96 +/- 0.14 vs. 0.81 +/- 0.10 ml/min, P less than 0.05) as was the single nephron glomerular filtration rate (54 +/- 7.1 vs. 46 +/- 4.0 nl/min, P less than 0.05). The single glomerular afferent plasma flow was comparable in both groups. Enalapril reduced mean glomerular capillary hydraulic pressure from the normal value of 51 +/- 1 mmHg (untreated rats) to a value lower than normal (44 +/- 1 mmHg, P less than 0.001). These hemodynamic changes were associated with a significant reduction in afferent (approximately 23%) and efferent (approximately 26%) arteriolar resistance. The mean ultrafiltration coefficient was two times higher in the enalapril (0.126 +/- 0.027 nl/s per mmHg) than in the untreated group (0.061 +/- 0.023 nl/s per mmHg). The clearance of dextran macromolecules relative to that of inulin was significantly reduced for all molecular sizes studied (26-64 A) in enalapril-treated vs. untreated rats. Theoretical analysis of dextran fractional clearances using a heteroporous model of neutral solute transport across the glomerular capillary wall indicated that enalapril affected glomerular membrane size selective properties, reducing uniformly the radius of hypothetical membrane pores. Enalapril treatment also significantly limited (P less than 0.01) the development of glomerular structural lesions (mean percentage of sclerotic glomeruli was 4.2 +/- 3.5% [treated] vs. 28 +/- 15% [untreated] rats at the end of the study) as well as tubulo-interstitial damage. These results suggest that the protective effect of enalapril on the development of proteinuria and glomerular sclerosis in this model is due to its property of ameliorating size selectivity and hydraulic permeability of the glomerular capillaries.
Collapse
Affiliation(s)
- A Remuzzi
- Mario Negri Institute for Pharmacological Research, Ospedali Riuniti di Bergamo, Italy
| | | | | | | | | |
Collapse
|
34
|
Harris KP, Purkerson ML, Yates J, Klahr S. Lovastatin ameliorates the development of glomerulosclerosis and uremia in experimental nephrotic syndrome. Am J Kidney Dis 1990; 15:16-23. [PMID: 2294729 DOI: 10.1016/s0272-6386(12)80587-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The nephrotic syndrome was induced in uninephrectomized Sprague-Dawley rats using repeated injections of puromycin and protamine sulfate. Preliminary studies demonstrated that the administration of lovastatin (4 mg/kg body weight [BW] subcutaneously [SC] daily) was effective at lowering plasma cholesterol over a 63-day period, although not to normal values. Subsequently, two groups of rats that had been made nephrotic were studied; one group (n = 8) received lovastatin, the other (n = 9) received the vehicle alone. Blood and urine collections were made at days 0, 23, and 60. Clearance studies and renal histology were obtained at day 60. Lovastatin-treated rats had significantly lower cholesterol at day 23 and 60 than vehicle-treated rats (270.5 +/- 39.7 v 501.7 +/- 81.9 and 148.2 +/- 10.7 v 268.2 +/- 40.8 mg/dL, P less than 0.05). Both groups of rats developed equivalent degrees of proteinuria and hypoalbuminemia. At day 60, the lovastatin-treated rats had a lower urea: 18.3 +/- 4.1 v 55.8 +/- 9.6 mmol/L (blood urea nitrogen [BUN] 51.2 +/- 111.5 v 156.2 +/- 27.0 mg/dL, P less than 0.02) and greater unulin clearance (1.83 +/- 0.42 v 0.82 +/- 0.41 mL/min/kg BW, P less than 0.05) than the vehicle-treated rats. Neither group was hypertensive and the blood pressure (BP) was similar in both groups. The percentage of glomeruli showing no changes or minimal histological changes was significantly greater in the lovastatin-treated group (26.5% +/- 5.7% v 8.33% +/- 3.33%, P less than 0.02), and there were more glomeruli with global sclerosis in the vehicle-treated group.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- K P Harris
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110
| | | | | | | |
Collapse
|
35
|
Messina A, Davies DJ, Ryan GB. Protamine sulphate-induced proteinuria: the roles of glomerular injury and depletion of polyanion. J Pathol 1989; 158:147-56. [PMID: 2754545 DOI: 10.1002/path.1711580210] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
It has been claimed that intrarenal injection of polycations results in proteinuria due to neutralization of glomerular basement membrane polyanionic charge without any glomerular morphological changes. To study the effects of polycation infusion on the renal glomerulus, the left kidney of rats was directly injected with protamine sulphate through the renal artery. Urine was collected from each kidney before and after injection, and protein excretion rates were determined. Ninety minutes after completion of the injection both kidneys were perfusion-fixed and the morphology and colloidal iron staining of the kidneys were studied by light and electron microscopy. Intrarenal injection of 0.5, 1, and 2 mg of protamine sulphate produced minimal or mild proteinuria in the majority of animals. Higher doses (5 mg) commonly resulted in decreased protein excretion associated with oliguria. Colloidal iron staining of glomerular polyanionic sites was undiminished when compared with control kidneys. Injection of protamine sulphate resulted in capillary thrombosis and severe damage to both glomerular and tubular epithelium in 6 of 16 kidneys. In the remaining kidneys, milder focal changes were apparent. Although its mechanism of action is unclear, it is apparent that protamine sulphate, even in small doses, is toxic to the cellular components of the glomerulus and tubules, thus accounting for the range of changes observed in renal function.
Collapse
Affiliation(s)
- A Messina
- Department of Anatomy, University of Melbourne, Parkville, Victoria, Australia
| | | | | |
Collapse
|
36
|
Conger JD, Falk SA, Gillum DM. The protective mechanism of thyroidectomy in a rat model of chronic renal failure. Am J Kidney Dis 1989; 13:217-25. [PMID: 2919601 DOI: 10.1016/s0272-6386(89)80055-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Selective thyroidectomy (Tx) has been shown to attenuate proteinuria and disease progression in models of chronic renal failure (CRF). In this investigation, four groups of Munich-Wistar rats were studied to determine if glomerular dynamics or another renal metabolic consequence of Tx was responsible for the protective effect as measured by 24-hour protein excretion (UPROT). The groups were TxT4, thyroxine-replaced Tx rats with five-sixths nephrectomy; Tx, Tx rats not receiving replacement thyroxine with five-sixths nephrectomy; TxI, Tx rats not receiving replacement thyroxine with five-sixths nephrectomy that were given continuous intraperitoneal isoproterenol to restore systemic and renal hemodynamics; and TxT4(C), two-kidney Tx rats receiving replacement thyroxine that served as normal controls. Five-sixths nephrectomy was carried out 2 weeks after Tx, and experiments were carried out 1 week later. Serum T4 was profoundly reduced and there was failure to gain weight in Tx and TxI rats, despite similar protein intakes in all groups. Cardiac output was reduced in Tx, but was similar in TxI to levels in TxT4 rats. Whole-kidney glomerular filtration rate was lower in Tx, at 0.145 +/- 0.052 mL/min (P less than 0.05), but similar in TxI (0.305 +/- 0.147 mL/min) to that in TxT4 rats (0.317 +/- 0.135 mL/min). Twenty-four-hour urinary protein, which was 129 +/- 57 mg in TxT4, was reduced in Tx to 9 +/- 3 mg (P less than 0.01) but restored in TxI to 89 +/- 30 mg, a level similar to that in TxT4.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J D Conger
- Department of Medicine, University of Colorado, Health Sciences Center, Denver
| | | | | |
Collapse
|
37
|
Abstract
The influence of compensatory hyperfunction that occurs following unilateral nephrectomy on glomerular solute transport was determined in awake, unanesthetized dogs by renal clearance studies. Two groups of dogs were studied using different test solutes: group I (N = 5) using inulin, iothalamate, creatinine and sodium p-aminohippurate; and group II (N = 6) using creatinine, neutral dextran (3000 to 50,000 daltons) and sodium p-aminohippurate. Compensatory hyperfunction, as assessed by the increase in creatinine clearance per kidney, was 43 +/- 7% and 39 +/- 11% in the group I and II dogs, respectively. The inulin to creatinine and iothalamate to creatinine clearance ratios in the group I dogs were 0.93 +/- 0.07 and 1.00 +/- 0.04 before unilateral nephrectomy. The respective values after unilateral nephrectomy of 0.86 +/- 0.04 and 0.89 +/- 0.05 were lower but not statistically different. In the group II dogs, dextran to creatinine clearance ratios (dextran fractional clearance) over the molecular weight range studied also did not change significantly following unilateral nephrectomy. The magnitude of the change in dextran fractional clearance following unilateral nephrectomy was qualitatively consistent with that predicted by previous models of glomerular macromolecular transport based on membrane pore theory. A lack of quantitative agreement with these models, however, precluded a calculation of the changes in glomerular functional parameters following unilateral nephrectomy. Significant alterations in fractional clearance for neutral macromolecules do not occur following unilateral nephrectomy in the dog.
Collapse
Affiliation(s)
- L W Henderson
- Department of Medicine, Veterans Administration Medical Center, San Diego, California
| | | |
Collapse
|
38
|
Ginevri F, Ghiggeri GM, Candiano G, Oleggini R, Bertelli R, Piccardo MT, Perfumo F, Gusmano R. Peroxidative damage of the erythrocyte membrane in children with nephrotic syndrome. Pediatr Nephrol 1989; 3:25-32. [PMID: 2484656 DOI: 10.1007/bf00859620] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The structural composition of erythrocyte ghosts was analysed in children affected by steroid-responsive (SRNS) and unresponsive nephrotic syndrome (SUNS). No variation of either intrinsic or extrinsic ghost proteins was found by discontinuous SDS-electrophoresis associated with a very sensitive double staining technique. By contrast, the composition of inner-layer phospholipids--phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS)--was altered in SRNS with minor changes also involving phosphatidic acid, phosphatidyl inositol and lysophosphatidyl choline. Signs of peroxidative damage were present in both SRNS and SUNS ghosts and inside the cells; these included high levels of fluorescent amino-iminopropene derivates of PE and PS, increased intraerythrocytic amounts of malonyldialdehyde and decreased levels of reduced glutathione. Taken together these results support the concept that in SRNS and SUNS erythrocytes are target cells for peroxidative damage. In SRNS peroxidation of membrane lipids results in a marked alteration of the phospholipid composition of erythrocyte ghosts.
Collapse
Affiliation(s)
- F Ginevri
- Department of Nephrology and Dialysis, G. Gaslini Institute, Genoa, Italy
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Baylis C, Fredericks M, Leypoldt J, Frigon R, Wilson C, Henderson L. The mechanisms of proteinuria in aging rats. Mech Ageing Dev 1988; 45:111-26. [PMID: 2462659 DOI: 10.1016/0047-6374(88)90101-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Aging is associated with the appearance of a selective proteinuria which cannot be attributed to any specific underlying renal disease. The present studies were conducted in conscious, chronically catheterized young (3-4 months), non-proteinuric male rats and old (22-25 months), proteinuric males to determine the mechanism(s) of the proteinuria. Compared with young males, old proteinuric rats had increased blood pressure, reduced glomerular filtration rate (GFR) and renal plasma flow and heavy proteinuria. Fractional clearance of neutral dextran (D) and anionic dextran sulfate (DS) were both significantly increased at the 36 A molecular radius in old rats; the increase in DS fractional clearance being greater than the increase in D fractional clearance. The proteinuria of aging is therefore due to moderate increases in glomerular permeability and, more importantly, to loss of fixed glomerular polyanion. Striking glomerular morphologic changes were also evident in the old rats including thickening of the glomerular basement membrane and extensive glomerular sclerosis.
Collapse
Affiliation(s)
- C Baylis
- Department of Physiology, West Virginia University, Morgantown 26506
| | | | | | | | | | | |
Collapse
|
40
|
Anderson S, Diamond JR, Karnovsky MJ, Brenner BM. Mechanisms underlying transition from acute glomerular injury to late glomerular sclerosis in a rat model of nephrotic syndrome. J Clin Invest 1988; 82:1757-68. [PMID: 2846658 PMCID: PMC442746 DOI: 10.1172/jci113789] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Functional and morphologic measurements were performed in Munich-Wistar rats after a single central venous injection of puromycin aminonucleoside (PA) or saline vehicle (sham). During phase I, PA rats exhibited overt nephrotic syndrome and impaired glomerular filtration, primarily due to a reduction in the glomerular capillary ultrafiltration coefficient. The morphologic counterpart of the latter consisted of effacement of glomerular epithelial cell foot processes and decrease in the number of filtration slit diaphragms. Administration of the angiotensin I converting enzyme inhibitor (CEI) enalapril to PA rats did not ameliorate glomerular dysfunction. During phase II, PA rats exhibited spontaneous resolution of proteinuria, impaired function, and morphologic abnormalities. However, PA rats now demonstrated marked glomerular capillary hypertension and continued, albeit lesser, reductions in the ultrafiltration coefficient. Concurrent CEI administration modestly lowered systemic arterial pressure, and normalized the glomerular capillary hydraulic pressure and ultrafiltration coefficient. Additional rats were studied during phase III, 70 wk after injection. In PA rats, prior glomerular hypertension was associated with development of recurrent proteinuria and extensive glomerular sclerosis, whereas concurrent CEI administration limited these parameters to values comparable to those in sham rats. Glomerular hypertension thus may explain the development of glomerular sclerosis and renal failure long after an episode of acute glomerular injury.
Collapse
Affiliation(s)
- S Anderson
- Renal Division, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | | | | | | |
Collapse
|
41
|
Remuzzi A, Puntorieri S, Mazzoleni A, Remuzzi G. Sex related differences in glomerular ultrafiltration and proteinuria in Munich-Wistar rats. Kidney Int 1988; 34:481-6. [PMID: 3199667 DOI: 10.1038/ki.1988.206] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Munich-Wistar rats (MWF/Ztm), originally selected for high number of superficial glomeruli, were used to correlate abnormal urinary protein excretion with glomerular hemodynamics and glomerular morphology. Two animal groups were used, one of male and one of female rats. They were kept periodically in metabolic cages to determine urinary protein excretion. All animals were fed standard rat chow. In male animals protein excretion, evaluated at seven weeks of age, was already significantly higher than in females (17 +/- 11 vs. 8 +/- 3 mg/24 hr), and then progressively increased averaging 291 +/- 51 mg/24 hr at week 21. In females urinary protein excretion was within the normal range up to week 18 and averaged 25 +/- 13 mg/24 hr at week 21. Body and kidney weight at the end of the experimental period were significantly higher in males than in females. Whole kidney inulin clearance (CIn) and single nephron glomerular filtration rate (SNGFR) were significantly higher in male than in female rats, while mean glomerular capillary hydraulic pressure (PGC) and transcapillary hydraulic pressure difference (delta P) were comparable. Single nephron glomerular plasma flow (QA) and afferent and efferent arteriolar resistance were comparable in male and female rats. The calculated glomerular ultrafiltration coefficient (Kf) was significantly higher in male than in female MWF/Ztm rats. No significant differences were detected between the two groups in the total number of glomeruli, and in glomerular size. These findings indicate that male MWF/Ztm rats develop spontaneous proteinuria, which progressively increases with the age.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- A Remuzzi
- Istituto di Ricerche Farmacologiche Mario Negri, Bergamo, Italy
| | | | | | | |
Collapse
|
42
|
|
43
|
Fries JW, Mendrick DL, Rennke HG. Determinants of immune complex-mediated glomerulonephritis. Kidney Int 1988; 34:333-45. [PMID: 2971836 DOI: 10.1038/ki.1988.186] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have studied the influence of steric factors on the clinico-pathologic expression of immune complex-mediated glomerular diseases, utilizing ferritin as an exogenous antigen. The tracer was planted in the left kidney either in the subepithelial layer of the glomerular capillary wall or on the endothelium and lamina rara interna. Subepithelial immune complex formation resulted in non-inflammatory injury with heterologous and autologous proteinuric phases (115 +/- 16 mg/24 hrs on day 2; 183 +/- 16 mg/24 hrs on day 9) lasting four to five weeks. The glomerular filtration rate of the experimental left kidney was reduced by 19% at day 3, and was increased by 20% at day 12 over right kidney values. Immune complexes persisted for more than seven weeks in the lamina rara externa. In contrast, immune complex deposition on the endothelium and in the lamina rara interna led to acute transient anuria, with a 38% drop in glomerular filtration rate at one hour, massive platelet accumulation, followed by a strong inflammatory response. Proteinuria did not develop. Functional and structural integrity was restored within 24 hours, with complete clearing of immune deposits. We conclude that the distribution of exogenous antigens within the capillary wall determines the structural and functional expression of immune-mediated glomerular diseases.
Collapse
Affiliation(s)
- J W Fries
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts
| | | | | |
Collapse
|
44
|
Alfino PA, Neugarten J, Schacht RG, Dworkin LD, Baldwin DS. Glomerular size-selective barrier dysfunction in nephrotoxic serum nephritis. Kidney Int 1988; 34:151-5. [PMID: 2460659 DOI: 10.1038/ki.1988.160] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have previously reported amelioration of heavy proteinuria, vascular sclerosis and glomerular structural damage by antihypertensive therapy in nephrotoxic serum nephritis (NSN). In the present study, we examine glomerular permselectivity in this hypertensive form of NSN and the effect of hypertension treatment on size-selective barrier function. Mean arterial pressure was maintained at normotensive levels (mean 123 +/- 3 mm Hg) with a combination of hydralazine, hydrochlorthiazide and reserpine in 7 nephritic rats, while 10 untreated rats remained hypertensive (mean 165 +/- 4 mm Hg). At six weeks, glomerular filtration rate was reduced in untreated rats (mean 0.54 ml/min) but was preserved in those rendered normotensive (mean 1.71 ml/min), P less than 0.02). Twenty-four-hour urinary protein excretion, mean 371 +/- 74 mg in hypertensive nephritic rats, was markedly reduced in rats on the antihypertensive regimen to a mean of 120 +/- 17 mg (P less than 0.02), as was 24-hour urinary gamma-globulin excretion (mean 35 +/- 9 mg in untreated vs. 16 +/- 2 mg in treated). Fractional clearances of tritiated polydisperse neutral dextrans were significantly enhanced for molecular radii exceeding 50 angstroms in hypertensive animals, indicative of a loss of glomerular size permselectivity. Rats on antihypertensive therapy did not develop such a size selective defect. Thus, hypertensive rats with nephrotoxic serum nephritis develop "gaps" in the glomerular basement membrane which allow the excretion of large molecular weight neutral dextrans and gamma-globulin. This defect in glomerular permselectivity can be averted with antihypertensive therapy.
Collapse
Affiliation(s)
- P A Alfino
- Department of Medicine, New York University School of Medicine, New York
| | | | | | | | | |
Collapse
|
45
|
Abstract
In summary, both the developing atherosclerotic and FSGS lesions seem to share certain postulated pathophysiologic mechanisms, including endothelial cell injury, macrophage infiltration, hyperlipoproteinemia, and hypertension. As depicted in Figure 1, any initial glomerular injury results in flux of macromolecular substances into the glomerular mesangium. As an adjunct to increased glomerular barrier dysfunction, hyperlipoproteinemia is believed to secondarily develop from the dramatic losses of albumin, stimulating increased hepatic lipoprotein synthesis and the loss of lipoprotein lipase-activating substance into the urine which would effectively produce a reduction in circulating chylomicra and triglyceride catabolism. Certain elevated circulating lipoproteins could, theoretically, pass through the damaged glomerular filter into the mesangium, thereby enhancing the flux of macromolecules. Also associated with certain experimental glomerular disorders is the development of glomerular hypertension, as manifested by an elevated glomerular capillary hydrostatic pressure (PGC), which can further augment macromolecular flux into the mesangium. Overloading of the glomerular mesangium by the above mechanisms is believed to be an injurious stimulus for MC to both proliferate and produce excess mesangial matrix substance. Both of these events are thought to be pathologic harbingers of glomerulosclerosis. Glomerular hypertension is also capable of damaging endothelial cells within the glomerular microcirculation, and this purportedly can activate platelets and result in glomerular thrombosis. At present, it is unclear how glomerular thrombosis produces increased mesangial cell injury; however, this process is believed to cause both systemic and glomerular hypertension which may serve as intermediary mechanisms producing the untoward effects of mesangial cell proliferation and matrix overproduction.
Collapse
Affiliation(s)
- J R Diamond
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115
| | | |
Collapse
|
46
|
Grond J, Muller EW, van Goor H, Weening JJ, Elema JD. Differences in puromycin aminonucleoside nephrosis in two rat strains. Kidney Int 1988; 33:524-9. [PMID: 3361753 DOI: 10.1038/ki.1988.29] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Administration of puromycin aminonucleoside (PAN) to Wistar rats induces proteinuria and enhanced mesangial deposition of circulating macromolecules. After proteinuria of longer duration focal and segmental glomerular hyalinosis and sclerosis (FSGHS) develops. The present report analyzes these aspects of PAN nephrosis in PVG/c rats, a strain previously shown to be remarkably resistant to proteinuria and FSGHS with aging or after uninephrectomy. In Wistar rats multiple injections of PAN during five months resulted in sustained severe proteinuria and FSGHS lesions in 8.1 +/- 1.0% (mean +/- 1 SEM) of their glomeruli (N = 6). In PVG/c rats a 1.3-fold higher dose of PAN was needed to induce chronic proteinuria similar to the Wistar rats. After five months 3.3 +/- 0.9% of their glomeruli showed FSGHS (N = 6, P less than 0.01) and the glomerular lesions were considerably less advanced. In acute PAN nephrosis induced by a single intravenous injection of PAN the mesangium of Wistar rats contained large amounts of lipid in contrast to a few small mesangial lipid droplets in nephrotic PVG/c rats. After injection of colloidal carbon in nephrotic PVG/c rats no enhanced carbon accumulation was found in the mesangium when compared to nonproteinuric controls. This result clearly differs from the increased mesangial sequestration of circulating material in nephrotic Wistar, and most other rat strains. The unchanged mesangial traficking of macromolecules in nephrotic PVG/c rats and the low incidence of FSGHS lesions in the presence of sustained glomerular proteinuria may reflect a relative resistance to PAN-induced glomerular damage in this particular rat strain.
Collapse
Affiliation(s)
- J Grond
- Department of Pathology, University of Groningen, The Netherlands
| | | | | | | | | |
Collapse
|
47
|
Eddy AA, Michael AF. Acute tubulointerstitial nephritis associated with aminonucleoside nephrosis. Kidney Int 1988; 33:14-23. [PMID: 3258389 DOI: 10.1038/ki.1988.3] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The aminonucleoside of puromycin (PAN) induces nephrotic syndrome in rats. We studied the tubulointerstitial cellular (TIC) infiltrate previously unrecognized in this model. Rats received one i.p. injection of PAN (15 mg/100 g) and were sacrificed at 1, 3, 4, 5, 7, 14, 20 and 28 days. Frozen kidney sections and peripheral blood cells were stained with a panel of anti-rat monoclonal antibodies and quantitated by epifluorescence microscopy. An increase in Ia+ cells (60/1000 TIC) (P less than 0.001) and OX42+ macrophages (MO) (18/1000 TIC) (P less than 0.05) were observed on day 5. On day 7 the infiltrate consisted of OX19+ T-lymphocytes (29/1000 TIC) (P less than 0.001) and OX42+ MO (68/1000 TIC) (P less than 0.001). The majority of the lymphocytes expressed the OX8 cytotoxic T cell marker (23/1000 TIC) (P less than 0.001). The severe mixed cellular lesion present on day 14 was dominated by OX42+ MO (113/1000 TIC) (P less than 0.001). With resolution of proteinuria on days 20 and 28, the infiltrate decreased, although OX42+ MO persisted on day 28 (46/1000 TIC) (P less than 0.001). The severity of the cellular lesion correlated with the degree of albuminuria (r = 0.57 to 0.81 for the antibody panel). Expression of Ia antigens by proximal tubular epithelial cells markedly decreased during peak proteinuria but normalized by day 28. Increased deposition of C3 and IgG was not detected. Reversible tubulointerstitial nephritis develops in PAN-treated rats and may be a consequence of severe proteinuria.
Collapse
Affiliation(s)
- A A Eddy
- Hospital for Sick Children, Toronto, Ontario, Canada
| | | |
Collapse
|
48
|
Davin JC, Davies M, Foidart JM, Foidart JB, Dechenne CA, Mahieu PR. Relation between urinary proteinases and proteinuria in rats with a glomerular disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 240:267-73. [PMID: 3072845 DOI: 10.1007/978-1-4613-1057-0_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- J C Davin
- Department of Medicine, State University of Liege, Belgium
| | | | | | | | | | | |
Collapse
|
49
|
Marinides GN, Groggel GC, Cohen AH, Cook T, Baranowski RL, Westenfelder C, Border WA. Failure of angiotensin converting enzyme inhibition to affect the course of chronic puromycin aminonucleoside nephropathy. THE AMERICAN JOURNAL OF PATHOLOGY 1987; 129:394-401. [PMID: 2823616 PMCID: PMC1899718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The effects of the angiotensin converting enzyme (ACE) inhibitor enalapril on the proteinuria and degree of focal glomerular sclerosis hyalinosis (FSH) in chronic puromycin aminonucleoside nephropathy (PAN) were examined. Chronic PAN was induced in male Sprague-Dawley rats by seven subcutaneous injections of puromycin aminonucleoside (20 mg/kg) over 10 weeks (Groups I and II). Group II rats also received enalapril 10 mg/kg/day in the drinking water throughout the study (12 weeks). Group III rats served as age-matched controls. Proteinuria was similar in Groups I and II (35.5 +/- 9.7 versus 29.1 +/- 4.1 mg protein/mg creatinine, mean +/- SEM, P greater than 0.05). Serum creatinine remained unchanged in Group I, but rose from 0.7 +/- 0.04 to 1.2 +/- 0.1 mg/dl (mean +/- SEM, P less than 0.05) in Group II. FSH was 13.8% in Group I, 12.9% in Group II (P greater than 0.05), and 0.6% in Group III. There was no significant difference in glomerular lipid content and in immunofluorescence for rat albumin, fibrinogen, IgM, IgG, and C3 between Groups I and II. ACE activity was inhibited by 94% in serum, 83% in lungs, and 92% in kidneys; and blood pressure response to. Angiotensin I challenge was decreased by 50% in rats similarly treated with enalapril versus controls. In summary, proteinuria and glomerular sclerosis in this model are not affected by ACE inhibition.
Collapse
Affiliation(s)
- G N Marinides
- Division of Nephrology, University of Utah Medical Center, Salt Lake City 84132
| | | | | | | | | | | | | |
Collapse
|
50
|
Ulich TR, Meline JA, Ni RX, Keys M, Wu CH. Stable analogs of prostaglandins E1 and F2 alpha ameliorate the proteinuria of aminonucleoside-of-puromycin nephrosis in Lewis rats. THE AMERICAN JOURNAL OF PATHOLOGY 1987; 129:133-9. [PMID: 3499082 PMCID: PMC1899686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Prostaglandins have been implicated by previous investigators in the pathogenesis of the nephrotic syndrome. A single subcutaneous injection of 1 mg/kg of stable analogs of prostaglandins E1 or F2 alpha (15[S]-15-methyl -PGE1 [M-PGE1] and -PGF2 alpha [M-PGF2 alpha]) was found in the present study to dramatically decrease proteinuria on Day 10 of puromycin aminonucleoside (PAN) nephrosis in Lewis rats. The decrease in proteinuria was mediated at least in part by a decrease in glomerular filtration rate (GFR), as quantitated by inulin clearances in nephrotic control and prostaglandin-treated rats. M-PGE1, moderately, and M-PGF2 alpha, to a lesser degree, also decreased the GFR in normal rats. Interestingly, the GFR was dramatically decreased in nephrotic as compared with nonnephrotic control rats, which suggests that PAN nephrosis may not be an ideal experimental model for human minimal change nephrosis in which the GFR is usually not severely compromised. The prostaglandin-induced decrease in GFR in both nephrotic and normal rats was coincident with a drop in systemic blood pressure. Nephrotic rats, however, had a slightly higher baseline blood pressure than normals, and the hypotensive effects of both prostaglandins were much less in nephrotic than in normal rats. The decrease in proteinuria was not related to a cytoprotective effect, as indicated by the failure of daily doses of 5 micrograms/kg M-PGE1 to reduce proteinuria 6, 8, or 10 days after injection of puromycin aminonucleoside. The similar antiproteinuric effects of prostaglandin synthesis inhibitors and of pharmacologic doses of prostaglandins are somewhat paradoxical but are reminiscent of the similarly paradoxical mutual antiinflammatory effects of these agents. The high doses of prostaglandins required to reduce proteinuria as well as their reduction of blood pressure and GFR will limit their clinical usefulness in the nephrotic syndrome.
Collapse
Affiliation(s)
- T R Ulich
- Department of Pathology, University of California, Irvine Medical School 92717
| | | | | | | | | |
Collapse
|