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G B Ryan - One of the best experts on this subject based on the ideXlab platform.
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biphasic glomerular hypertrophy in rats administered puromycin Aminonucleoside
Kidney International, 1996Co-Authors: Meroe M Cahill, G B Ryan, John F BertramAbstract:Recent evidence suggests that glomerular hypertrophy is a key event in the development of focal and segmental glomerulosclerosis and hyalinosis (FSGS) in humans and in many experimental models of FSGS. The initial aim of the present study was to determine if glomerular hypertrophy occurs in a puromycin Aminonucleoside (PAN) model of FSGS, previously considered not to involve glomerular hypertrophy. Upon identifying significant glomerular hypertrophy, our second aim was to determine the contribution of glomerular capillary growth to this hypertrophy. Female Sprague-Dawley rats (approximately 200 g) were administered either PAN (2 mg/100 g body wt) subcutaneously, or an equivalent volume of 0.9% saline at weeks 0, 1, 2, 4, 6, 8 and 10. Tissue was analyzed at weeks 7 and 13. Unbiased stereological methods were used to estimate a range of glomerular parameters. Mean glomerular tuft volume in PAN-treated rats was 48% greater than in saline-treated rats at seven weeks, and 63% greater at 13 weeks. Similar results were found for mean renal corpuscle volume. FSGS was absent at seven weeks and minor at 13 weeks. Two-way analysis of variance indicated: significant effects (P < 0.05 at least) of PAN on capillary length per glomerulus, capillary surface area per glomerulus, capillary diameter and length of capillaries per unit volume of glomerulus; and significant effects of time on capillary diameter, capillary length per unit volume of glomerulus and capillary surface area per unit volume of glomerulus. The mean length of capillaries per glomerulus was 45% greater in PAN-treated rats at week 7 and 22% greater in PAN-treated rats at week 13. Taken together, these results indicate a biphasic pattern of glomerular hypertrophy in this model. In the first phase (to 7 weeks), an increase in capillary length contributes to glomerular hypertrophy. In the second phase (7 to 13 weeks), the continued glomerular enlargement appears more likely to be due to an increase in capillary diameter and/or mesangial matrix expansion.
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Podocyte architecture in puromycin Aminonucleoside-treated rats administered tungsten or allopurinol.
Experimental nephrology, 1995Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:The role of xanthine oxidase as a source of reactive oxygen species in puromycin Aminonucleoside nephrosis was examined. The effects of allopurinol (a xanthine oxidase inhibitor as well as a reactive oxygen species scavenging enzyme) and tungsten (a specific xanthine oxidase inhibitor) on glomerular epithelial cell ultrastructure, renal xanthine oxidase and xanthine dehydrogenase activity, and urinary protein excretion were examined in puromycin Aminonucleoside-treated rats. Co-administration of allopurinol to such rats reduced proteinuria by approximately 70% over the 10 days studied, and reduced the degree of glomerular epithelial cell foot process effacement at both 5 and 10 days, compared to rats that received puromycin Aminonucleoside alone. Unexpectedly, co-administration of allopurinol to puromycin Aminonucleoside-treated rats did not reduce xanthine oxidase activity; however, the combined activity of xanthine oxidase and xanthine dehydrogenase in such animals was reduced on day 5. Co-administration of tungsten to puromycin Aminonucleoside-treated rats did not reduce proteinuria or alter the number of filtration slits. Rats co-administered tungsten and puromycin Aminonucleoside had significantly reduced renal xanthine oxidase and combined xanthine oxidase and xanthine dehydrogenase activities on days 5 and 10, compared to rats treated with puromycin Aminonucleoside alone. These results provide evidence that the protection provided by allopurinol in puromycin Aminonucleoside-treated rats is due to the antioxidant properties of allopurinol, rather than to its activities as a xanthine oxidase inhibitor.
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antioxidants protect podocyte foot processes in puromycin Aminonucleoside treated rats
Journal of The American Society of Nephrology, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P
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Antioxidants protect podocyte foot processes in puromycin Aminonucleoside-treated rats.
Journal of the American Society of Nephrology : JASN, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P < 0.01 in all cases) more glomerular epithelial cell filtration slits per unit length of glomerular basement membrane than rats treated with puromycin Aminonucleoside alone. In contrast, by scanning electron microscopy, the antioxidants were found to provide no protection against the changes occurring in glomerular epithelial cell bodies and major processes. These results provide further evidence of a role for reactive oxygen species in puromycin Aminonucleoside nephrosis and indicate that the antioxidants provide protection against the changes occurring in glomerular epithelial cell foot processes.
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Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies
Kidney international, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies. We examined the role of reactive oxygen species (ROS) in puromycin Aminonucleoside (PAN)-induced changes to glomerular epithelial cells (GECs) in vitro . Levels of superoxide anion (O 2 •− ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (HO • ) were measured in rat kidney-slice cultures containing PAN with or without antioxidants (allopurinol, probucol and α-tocopherol/ascorbic acid). GEC morphology was assessed after three days of culture using transmission (TEM) and scanning (SEM) electron microscopy. The effects of hypoxanthine on GEC ultrastructure was also assessed. O 2 •− , H 2 O 2 and HO • were generated when PAN was added to kidney-slice cultures in Medium 199. TEM morphometry revealed that incubation with PAN (100 µg/ml) significantly (P in vitro . When the hydrophobic antioxidants probucol or α-tocopherol/ascorbic acid, which scavenged/inhibited generation of O 2 •− , H 2 O 2 and HO • , were added to cultures containing PAN, the effect of PAN on foot processes was abolished. The TEM appearance of GECs now resembled that seen in control cultures. On the other hand, SEM revealed that probucol and α-tocopherol/ascorbic acid provided no protection against the changes induced by PAN in GEC cell bodies or major processes. Allopurinol provided no protection against the changes induced by PAN in GEC cell bodies, major processes or foot processes. The addition of hypoxanthine to kidney-slice cultures did not result in the generation of O 2 •− , H 2 O 2 or HO • , or alter GEC ultrastructure. These findings indicate that ROS play a role in PAN-induced alterations to GEC foot process architecture in vitro . However, the xanthine oxidase pathway does not appear to play a major role in generating ROS from PAN in vitro .
Jesús Mosquera - One of the best experts on this subject based on the ideXlab platform.
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increased expression of cd54 cd18 mhc class ii molecules and proliferating cell nuclear antigen in acute puromycin Aminonucleoside nephrosis
Nephron Experimental Nephrology, 2004Co-Authors: Lucas Fernandez, Maritza J. Romero, Jaimar Rincon, Jesús MosqueraAbstract:Cellular infiltration to renal tissues is an important feature during acute puromycin Aminonucleoside nephrosis (PAN) in rats. The mechanisms responsible for this infiltration are poorly understood. T
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melatonin decreases apoptosis and expression of apoptosis associated proteins in acute puromycin Aminonucleoside nephrosis
Nephrology Dialysis Transplantation, 2004Co-Authors: Adriana Pedreañez, Maritza J. Romero, Ninoska Viera, Jaimar Rincon, Jesús MosqueraAbstract:Background. The anti-apoptotic properties of melatonin have been demonstrated previously in several in vivo and in vitro studies. Previous reports have shown increased apoptosis during puromycin Aminonucleoside nephrosis (PAN). The aim of this study was to determine if melatonin (MEL) can prevent apoptosis and modify oxidative stress, an apoptosis inducer, in this experimental model. Methods. Rats were injected intraperitoneally with puromycin Aminonucleoside. In addition, by the intragastric route they received 1 mg/kg/day of MEL or vehicle 3 days before puromycin injection and throughout the experiment. Animals were sacrificed at weeks 1 and 2 of nephrosis and frozen renal sections were studied for apoptosis by TUNEL, for apoptosisassociated proteins by monoclonal and polyclonal antibodies, and for superoxide anion (O2 – ) by a histochemical method. Nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH), and the activities of superoxide dismutase (SOD) and catalase were measured in homogenized kidney tissue by appropriate biochemical and enzymatic methods. Results. Increases in apoptosis, p53, Fas and Fasligand were observed in nephrotic animals. MEL treatment decreased apoptosis at weeks 1 and 2 in the glomerular, interstitial and tubular compartments. This was accompanied by decreased expression of p53 (glomerulus, week 1; tubules, weeks 1 and 2), Fas (glomerulus and interstitium, week 2; tubules, weeks 1 and 2) and Fas-ligand (interstitum and tubules, week 2). Increased expression of Bcl-2-positive cells was observed at week 2 in all renal compartments in MELtreated animals. High levels of O2 – and NO generation and lipid peroxidation (MDA) were found in nephrotic animals. SOD and GSH remained unchanged, and only decreased catalase activity (week 1) was observed in PAN animals. Tendencies toward decreased values of O2 – and MDA content along with recovery of catalase activity (week 1) were observed in MEL-treated nephrotic animals, but were insignificant in magnitude. MEL, however, did significantly downregulate proapoptotic genes and upregulated anti-apoptotic genes. Conclusions. The data demonstrate that, in PAN, melatonin has anti-apoptotic effects, which might in part be independent of the modulation of the oxidative status.
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Increased oxidative stress and apoptosis in acute puromycin Aminonucleoside nephrosis.
International journal of experimental pathology, 2004Co-Authors: Jaimar Rincon, Maritza J. Romero, Ninoska Viera, Adriana Pedreañez, Jesús MosqueraAbstract:Accumulating evidence demonstrates that oxidative stress is one of the underlying mechanisms to induce apoptosis in different biological systems. The aim of this study was to examine the simultaneous presence and correlation between oxidative stress events, apoptosis, apoptosis-associated proteins and monocyte/macrophage infiltration during the course of acute puromycin Aminonucleoside nephrosis (PAN). To induce nephrosis, Sprague-Dawley rats were injected intraperitoneally with puromycin Aminonucleoside and killed at weeks 1 and 2 of nephrosis. Controls represent animals injected with 0.9% saline solution. Kidney sections were homogenized to measure nitric oxide (NO), malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase activities by appropriate enzymatic and biochemical methods. Renal frozen sections were studied for superoxide anion (O(2) (-)) by a histochemical method, for apoptosis by TUNEL (terminal-deoxynucleotidyl-transferase-mediated dUTP- digoxigenin nick end labelling) and for apoptosis-associated protein expression and monocyte/macrophage infiltration by monoclonal antibodies. Increased renal apoptosis, p53, Bax, Bcl-2 accompanied by increased O(2) (-) and NO generation, lipid peroxidation (MDA) and monocyte/macrophage infiltration were found in nephrotic animals. Renal oxidative stress (O(2) (-), NO and MDA) was correlated with apoptosis, p53 expression, monocyte/macrophage cells and proteinuria. Anti-oxidant molecules (SOD and GSH) remained unchanged apart from a decreased activity of catalase which correlated with glomerular apoptosis. In conclusion, the close correlation between the presence of apoptosis and oxidative events confirms the role of oxidative stress in the apoptosis observed during PAN.
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increased expression of cd54 cd18 mhc class ii molecules and proliferating cell nuclear antigen in acute puromycin Aminonucleoside nephrosis
Nephron, 2003Co-Authors: Lucas Fernandez, Maritza J. Romero, Jaimar Rincon, Jesús MosqueraAbstract:Cellular infiltration to renal tissues is an important feature during acute puromycin Aminonucleoside nephrosis (PAN) in rats. The mechanisms responsible for this infiltration are poorly understood. To elucidate the participation of adhesion molecules in PAN, nephrosis was induced in rats by intraperitoneal puromycin Aminonucleoside injection. Controls represent animals injected with a 0.9% saline solution. ICAM-1 (intercellular adhesion molecule 1), CD18 (beta chain of lymphocyte-function-associated antigen), LCA (leukocyte common antigen), ED1 (monocyte/macrophage marker), and proliferating cell nuclear antigen expressions were evaluated in renal tissues 1, 2, and 7 weeks after injection. Frozen sections from PAN rat kidneys showed increased expressions of ICAM-1 and its ligand, and these findings were associated with increased levels of LCA+ and ED1+ cells in glomerulus and interstitium. The kinetics of leukocyte infiltration was similar to the kinetics of ICAM-1 expression: high values at week 2 which returned to normal values at week 7. Increased glomerular and interstitial proliferative activities (proliferating cell nulear antigen positive cells) were also found at week 2 of nephrosis. There was a correlation between ICAM-1 expression and numbers of LCA+ and ED1+ cells and between numbers of LCA+ cells and proliferating cells in glomerulus and interstitium. Correlations between glomerular and tubular ICAM-1 expression, interstitial leukocyte infiltration, and glomerular, interstitial, and tubular proliferative activities with the proteinuria were also observed during the nephrotic phase. In addition, increased lymphocyte binding to PAN renal tissues was observed, and this binding was diminished by anti-LFA-1β monoclonal antibody pretreatment of lymphocytes. A similar result was found with anti-(CAM-1 monoclonal antibody pretreatment of renal tissues. Our results suggest that increased expression of ICAM-1 and proliferative activity could be important determinants in the renal hypercellularity found in this experimental model.
Sharon D Ricardo - One of the best experts on this subject based on the ideXlab platform.
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Podocyte architecture in puromycin Aminonucleoside-treated rats administered tungsten or allopurinol.
Experimental nephrology, 1995Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:The role of xanthine oxidase as a source of reactive oxygen species in puromycin Aminonucleoside nephrosis was examined. The effects of allopurinol (a xanthine oxidase inhibitor as well as a reactive oxygen species scavenging enzyme) and tungsten (a specific xanthine oxidase inhibitor) on glomerular epithelial cell ultrastructure, renal xanthine oxidase and xanthine dehydrogenase activity, and urinary protein excretion were examined in puromycin Aminonucleoside-treated rats. Co-administration of allopurinol to such rats reduced proteinuria by approximately 70% over the 10 days studied, and reduced the degree of glomerular epithelial cell foot process effacement at both 5 and 10 days, compared to rats that received puromycin Aminonucleoside alone. Unexpectedly, co-administration of allopurinol to puromycin Aminonucleoside-treated rats did not reduce xanthine oxidase activity; however, the combined activity of xanthine oxidase and xanthine dehydrogenase in such animals was reduced on day 5. Co-administration of tungsten to puromycin Aminonucleoside-treated rats did not reduce proteinuria or alter the number of filtration slits. Rats co-administered tungsten and puromycin Aminonucleoside had significantly reduced renal xanthine oxidase and combined xanthine oxidase and xanthine dehydrogenase activities on days 5 and 10, compared to rats treated with puromycin Aminonucleoside alone. These results provide evidence that the protection provided by allopurinol in puromycin Aminonucleoside-treated rats is due to the antioxidant properties of allopurinol, rather than to its activities as a xanthine oxidase inhibitor.
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antioxidants protect podocyte foot processes in puromycin Aminonucleoside treated rats
Journal of The American Society of Nephrology, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P
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Antioxidants protect podocyte foot processes in puromycin Aminonucleoside-treated rats.
Journal of the American Society of Nephrology : JASN, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P < 0.01 in all cases) more glomerular epithelial cell filtration slits per unit length of glomerular basement membrane than rats treated with puromycin Aminonucleoside alone. In contrast, by scanning electron microscopy, the antioxidants were found to provide no protection against the changes occurring in glomerular epithelial cell bodies and major processes. These results provide further evidence of a role for reactive oxygen species in puromycin Aminonucleoside nephrosis and indicate that the antioxidants provide protection against the changes occurring in glomerular epithelial cell foot processes.
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Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies
Kidney international, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies. We examined the role of reactive oxygen species (ROS) in puromycin Aminonucleoside (PAN)-induced changes to glomerular epithelial cells (GECs) in vitro . Levels of superoxide anion (O 2 •− ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (HO • ) were measured in rat kidney-slice cultures containing PAN with or without antioxidants (allopurinol, probucol and α-tocopherol/ascorbic acid). GEC morphology was assessed after three days of culture using transmission (TEM) and scanning (SEM) electron microscopy. The effects of hypoxanthine on GEC ultrastructure was also assessed. O 2 •− , H 2 O 2 and HO • were generated when PAN was added to kidney-slice cultures in Medium 199. TEM morphometry revealed that incubation with PAN (100 µg/ml) significantly (P in vitro . When the hydrophobic antioxidants probucol or α-tocopherol/ascorbic acid, which scavenged/inhibited generation of O 2 •− , H 2 O 2 and HO • , were added to cultures containing PAN, the effect of PAN on foot processes was abolished. The TEM appearance of GECs now resembled that seen in control cultures. On the other hand, SEM revealed that probucol and α-tocopherol/ascorbic acid provided no protection against the changes induced by PAN in GEC cell bodies or major processes. Allopurinol provided no protection against the changes induced by PAN in GEC cell bodies, major processes or foot processes. The addition of hypoxanthine to kidney-slice cultures did not result in the generation of O 2 •− , H 2 O 2 or HO • , or alter GEC ultrastructure. These findings indicate that ROS play a role in PAN-induced alterations to GEC foot process architecture in vitro . However, the xanthine oxidase pathway does not appear to play a major role in generating ROS from PAN in vitro .
John F Bertram - One of the best experts on this subject based on the ideXlab platform.
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biphasic glomerular hypertrophy in rats administered puromycin Aminonucleoside
Kidney International, 1996Co-Authors: Meroe M Cahill, G B Ryan, John F BertramAbstract:Recent evidence suggests that glomerular hypertrophy is a key event in the development of focal and segmental glomerulosclerosis and hyalinosis (FSGS) in humans and in many experimental models of FSGS. The initial aim of the present study was to determine if glomerular hypertrophy occurs in a puromycin Aminonucleoside (PAN) model of FSGS, previously considered not to involve glomerular hypertrophy. Upon identifying significant glomerular hypertrophy, our second aim was to determine the contribution of glomerular capillary growth to this hypertrophy. Female Sprague-Dawley rats (approximately 200 g) were administered either PAN (2 mg/100 g body wt) subcutaneously, or an equivalent volume of 0.9% saline at weeks 0, 1, 2, 4, 6, 8 and 10. Tissue was analyzed at weeks 7 and 13. Unbiased stereological methods were used to estimate a range of glomerular parameters. Mean glomerular tuft volume in PAN-treated rats was 48% greater than in saline-treated rats at seven weeks, and 63% greater at 13 weeks. Similar results were found for mean renal corpuscle volume. FSGS was absent at seven weeks and minor at 13 weeks. Two-way analysis of variance indicated: significant effects (P < 0.05 at least) of PAN on capillary length per glomerulus, capillary surface area per glomerulus, capillary diameter and length of capillaries per unit volume of glomerulus; and significant effects of time on capillary diameter, capillary length per unit volume of glomerulus and capillary surface area per unit volume of glomerulus. The mean length of capillaries per glomerulus was 45% greater in PAN-treated rats at week 7 and 22% greater in PAN-treated rats at week 13. Taken together, these results indicate a biphasic pattern of glomerular hypertrophy in this model. In the first phase (to 7 weeks), an increase in capillary length contributes to glomerular hypertrophy. In the second phase (7 to 13 weeks), the continued glomerular enlargement appears more likely to be due to an increase in capillary diameter and/or mesangial matrix expansion.
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Podocyte architecture in puromycin Aminonucleoside-treated rats administered tungsten or allopurinol.
Experimental nephrology, 1995Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:The role of xanthine oxidase as a source of reactive oxygen species in puromycin Aminonucleoside nephrosis was examined. The effects of allopurinol (a xanthine oxidase inhibitor as well as a reactive oxygen species scavenging enzyme) and tungsten (a specific xanthine oxidase inhibitor) on glomerular epithelial cell ultrastructure, renal xanthine oxidase and xanthine dehydrogenase activity, and urinary protein excretion were examined in puromycin Aminonucleoside-treated rats. Co-administration of allopurinol to such rats reduced proteinuria by approximately 70% over the 10 days studied, and reduced the degree of glomerular epithelial cell foot process effacement at both 5 and 10 days, compared to rats that received puromycin Aminonucleoside alone. Unexpectedly, co-administration of allopurinol to puromycin Aminonucleoside-treated rats did not reduce xanthine oxidase activity; however, the combined activity of xanthine oxidase and xanthine dehydrogenase in such animals was reduced on day 5. Co-administration of tungsten to puromycin Aminonucleoside-treated rats did not reduce proteinuria or alter the number of filtration slits. Rats co-administered tungsten and puromycin Aminonucleoside had significantly reduced renal xanthine oxidase and combined xanthine oxidase and xanthine dehydrogenase activities on days 5 and 10, compared to rats treated with puromycin Aminonucleoside alone. These results provide evidence that the protection provided by allopurinol in puromycin Aminonucleoside-treated rats is due to the antioxidant properties of allopurinol, rather than to its activities as a xanthine oxidase inhibitor.
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antioxidants protect podocyte foot processes in puromycin Aminonucleoside treated rats
Journal of The American Society of Nephrology, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P
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Antioxidants protect podocyte foot processes in puromycin Aminonucleoside-treated rats.
Journal of the American Society of Nephrology : JASN, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Whether a reduction in urinary protein excretion in rats coadministered puromycin Aminonucleoside and antioxidants was associated with a reduction in alterations to glomerular epithelial cell (podocyte) ultrastructure was examined. Daily urinary protein excretion was measured in rats that received a single i.v. injection of saline or puromycin Aminonucleoside with or without coadministration of antioxidants. The coadministration of alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase to puromycin Aminonucleoside-treated rats reduced proteinuria by approximately 90, 40, and 60%, respectively, over the 18-day period studied. For a second group of rats, daily urinary protein excretion was measured and kidneys were processed for light microscopy and transmission and scanning electron microscopy 4, 5, and 10 days after injection. Transmission electron microscopic morphometric analysis of glomeruli from puromycin Aminonucleoside-treated rats coadministered antioxidants revealed significantly reduced foot process effacement on Days, 4, 5, and 10 compared with rats that received puromycin Aminonucleoside alone. Thus, at Day 10, puromycin Aminonucleoside-treated rats coadministered alpha-tocopherol/ascorbic acid, dimethyl thiourea, or superoxide dismutase contained 90, 74, and 88% (P < 0.01 in all cases) more glomerular epithelial cell filtration slits per unit length of glomerular basement membrane than rats treated with puromycin Aminonucleoside alone. In contrast, by scanning electron microscopy, the antioxidants were found to provide no protection against the changes occurring in glomerular epithelial cell bodies and major processes. These results provide further evidence of a role for reactive oxygen species in puromycin Aminonucleoside nephrosis and indicate that the antioxidants provide protection against the changes occurring in glomerular epithelial cell foot processes.
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Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies
Kidney international, 1994Co-Authors: Sharon D Ricardo, John F Bertram, G B RyanAbstract:Reactive oxygen species in puromycin Aminonucleoside nephrosis: In vitro studies. We examined the role of reactive oxygen species (ROS) in puromycin Aminonucleoside (PAN)-induced changes to glomerular epithelial cells (GECs) in vitro . Levels of superoxide anion (O 2 •− ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (HO • ) were measured in rat kidney-slice cultures containing PAN with or without antioxidants (allopurinol, probucol and α-tocopherol/ascorbic acid). GEC morphology was assessed after three days of culture using transmission (TEM) and scanning (SEM) electron microscopy. The effects of hypoxanthine on GEC ultrastructure was also assessed. O 2 •− , H 2 O 2 and HO • were generated when PAN was added to kidney-slice cultures in Medium 199. TEM morphometry revealed that incubation with PAN (100 µg/ml) significantly (P in vitro . When the hydrophobic antioxidants probucol or α-tocopherol/ascorbic acid, which scavenged/inhibited generation of O 2 •− , H 2 O 2 and HO • , were added to cultures containing PAN, the effect of PAN on foot processes was abolished. The TEM appearance of GECs now resembled that seen in control cultures. On the other hand, SEM revealed that probucol and α-tocopherol/ascorbic acid provided no protection against the changes induced by PAN in GEC cell bodies or major processes. Allopurinol provided no protection against the changes induced by PAN in GEC cell bodies, major processes or foot processes. The addition of hypoxanthine to kidney-slice cultures did not result in the generation of O 2 •− , H 2 O 2 or HO • , or alter GEC ultrastructure. These findings indicate that ROS play a role in PAN-induced alterations to GEC foot process architecture in vitro . However, the xanthine oxidase pathway does not appear to play a major role in generating ROS from PAN in vitro .
Yasuhiko Tomino - One of the best experts on this subject based on the ideXlab platform.
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Podocin is translocated to cytoplasm in puromycin Aminonucleoside nephrosis rats and in poor-prognosis patients with IgA nephropathy
Cell and tissue research, 2015Co-Authors: Hiromitsu Fukuda, Tatsuo Sakai, Teruo Hidaka, Miyuki Takagi-akiba, Koichiro Ichimura, Juan Alejandro Oliva Trejo, Yu Sasaki, Juan Wang, Katsuhiko Asanuma, Yasuhiko TominoAbstract:Podocytes serve as the final barrier to urinary protein loss through a highly specialized structure called a slit membrane and maintain foot process and glomerular basement membranes. Podocyte injury results in progressive glomerular damage and accelerates sclerotic changes, although the exact mechanism of podocyte injury is still obscure. We focus on the staining gap (podocin gap) defined as the staining difference between podocin and synaptopodin, which are normally located in the foot process. In puromycin Aminonucleoside nephrosis rats, the podocin gap is significantly increased (p < 0.05) and podocin is translocated to the cytoplasm on days 7 and 14 but not on day 28. Surprisingly, the gap is also significantly increased (p < 0.05) in human kidney biopsy specimens of poor-prognosis IgA nephropathy patients. This suggests that the podocin gap could be a useful marker for classifying the prognosis of IgA nephropathy and indicating the translocation of podocin to the cytoplasm. Next, we find more evidence of podocin trafficking in podocytes where podocin merges with Rab5 in puromycin Aminonucleoside nephrosis rats at day 14. In immunoelectron microscopy, the podocin positive area was significantly translocated from the foot process areas to the cytoplasm (p< 0.05) on days 7 and 14 in puromycin Aminonucleoside nephrosis rats. Interestingly, podocin is also translocated to the cytoplasm in poor-prognosis human IgA nephropathy. In this paper, we demonstrate that the translocation of podocin by endocytosis could be a key traffic event of critical podocyte injury and that the podocin gap could indicate the prognosis of IgA nephropathy.
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podocyte migration during nephrotic syndrome requires a coordinated interplay between cathepsin l and α3 integrin
Journal of Biological Chemistry, 2004Co-Authors: Jochen Reiser, Karen Honey, Isao Shirato, Katsuhiko Asanuma, Kazumi Ishidoh, Andreas Hug, Thomas M Mundel, Eiki Kominami, Jordan A Kreidberg, Yasuhiko TominoAbstract:Podocyte foot process effacement and disruption of the slit diaphragm are typically associated with glomerular proteinuria and can be induced in rats by the injection of puromycin Aminonucleoside. Here, we show that the induction of puromycin Aminonucleoside nephrosis involves podocyte migration conducted by a coordinated interplay between the cysteine protease cathepsin L and alpha(3) integrin. Puromycin Aminonucleoside treatment up-regulates cathepsin L expression in podocytes in vivo as well as expression and enzymatic activity of cathepsin L in podocytes in vitro. Isolated podocytes from mice lacking cathepsin L are protected from cell puromycin Aminonucleoside-induced cell detachment. The functional significance of cathepsin L expression was underscored by the observation that puromycin Aminonucleoside-induced cell migration was slowed down in cathepsin L-deficient podocytes and by the preservation of cell-cell contacts and expression of vital slit diaphragm protein CD2AP. Cathepsin L expression and activity were induced in podocytes lacking alpha(3) integrin. Similarly, acute functional inhibition of alpha(3) integrin in wild type podocytes with a blocking antibody increased the expression of cathepsin L activity. Down-regulation of alpha(3) integrin protected against puromycin Aminonucleoside-induced podocyte detachment. In summary, these data establish that podocyte foot process effacement is a migratory event involving a novel interplay between cathepsin L and alpha(3) integrin.
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map lc3 a promising autophagosomal marker is processed during the differentiation and recovery of podocytes from pan nephrosis
The FASEB Journal, 2003Co-Authors: Katsuhiko Asanuma, Isao Shirato, Eiki Kominami, Isei Tanida, Takashi Ueno, Hisatsugu Takahara, Tomohito Nishitani, Yasuhiko TominoAbstract:Microtubule-associated protein 1 light chain 3 (LC3) is a unique modifier protein. LC3-I, the cytosolic form, is modified to LC3-II, the membrane-bound form, by a mechanism similar to ubiquitylation by E1- and E2-like enzymes, Apg7p and Apg3p, respectively. In the present study, we found that LC3-I is processed to LC3-II during the differentiation and recovery from puromycin Aminonucleoside-induced nephrosis of podocytes. LC3 is especially expressed in the podocytes of rat kidney as the membrane-bound form LC3-II. Biochemical analysis using a conditionally immortalized mouse podocyte clone (MPC) revealed that LC3-I is processed to LC3-II during the differentiation of cells into mature podocytes and accumulates in the membrane-rich fraction of the cell lysate. LC3-II-localized vesicles, which differ from lysosomes and endosomes, in differentiated MPC cells are morphologically similar to autophagic vacuoles during starvation-induced autophagy. During starvation-induced autophagy, autophagosomes fuses with lysosome and LC3-II on autophagosomes is finally degraded by lysosomal proteases. However, in differentiated MPC cells, little LC3-II on the vesicles is degraded by lysosomal proteases, suggesting that little LC3-II-localized vesicles in differentiated MPC cells fuse with lysosome. Furthermore, the LC3-II level in differentiated MPC cells increases with recovery from damage caused by experimental puromycin Aminonucleoside-induced nephrosis. These results suggest that LC3-II-localized vesicles play an important role in the physiological function of podocytes.
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Re-evaluation of foot process effacement in acute puromycin Aminonucleoside nephrosis
Kidney international, 1996Co-Authors: Sachiko Inokuchi, Yasuhiko Tomino, Hikaru Koide, Isao Shirato, Naoto Kobayashi, Tatsuo SakaiAbstract:Re-evaluation of foot process effacement in acute puromycin Aminonucleoside nephrosis. The sequence of morphological changes during foot process effacement in acute puromycin Aminonucleoside (PAN) nephrosis was examined by means of NaOH maceration and freeze cracking for scanning electron microscopy (SEM). The micrographs of SEM and those of transmission electron microscopy (TEM) were quantitatively analyzed by computerized morphometry, and were correlated with renal function. On day 2 after PAN injection, the slit length was moderately decreased by both shortening and degradation of the foot processes. On day 4, membrane-bounded vesicles were scattered in the lamina rara externa. During foot process effacement, the basal surface of podocytes developed palm-like domains that represented the cytoplasmic areas between interdigitation. The decrease in the length of podocyte cell borders paralleled the decrease of 24-hour creatinine clearance. The developement of the palm-like domains on the basal aspects of podocytes estimated by distance class analysis was closely correlated with the sudden onset of proteinuria. We conclude that foot process effacement in PAN nephrosis caused by the retraction and degradation of foot processes leads to the development of palm-like domains, which is correlated with podocyte detachment as well as massive proteinuria.