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Microalbuminuria and early renal response to lethal dose Shiga toxin type 2 in rats.

Ochoa F, Oltra G, Gerhardt E, Hermes R, Cohen L, Damiano AE, Ibarra C, Lago NR, Zotta E - Int J Nephrol Renovasc Dis (2012)

Bottom Line: Approximately 2%-4% of patients die during the acute phase, and one-third of the 96% who survive are at risk of chronic renal sequelae.In immunoperoxidase studies, the renal tubules and glomerular mesangium showed an increased expression of transforming growth factor β(1)(TGF-β(1)).The expression of megalin was decreased by immunoperoxidase and the cytoplasm showed a granular pattern of megalin expression by immunofluorescence techniques.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisiologia, Facultad de Medicina UBA, Buenos Aires, Argentina.

ABSTRACT
In Argentina, hemolytic uremic syndrome (HUS) constitutes the most frequent cause of acute renal failure in children. Approximately 2%-4% of patients die during the acute phase, and one-third of the 96% who survive are at risk of chronic renal sequelae. Little information is available about the direct effect of Shiga toxin type 2 (Stx2) on the onset of proteinuria and the evolution of toxin-mediated glomerular or tubular injury. In this work, rats were injected intraperitoneally with recombinant Escherichia coli culture supernatant containing Stx2 (sStx2; 20 μg/kg body weight) to induce HUS. Functional, immunoblotting, and immunohistochemistry studies were carried out to determine alterations in slit diaphragm proteins and the proximal tubule endocytic system at 48 hours post-inoculation. We detected a significant increase in microalbuminuria, without changes in the proteinuria values compared to the control rats. In immunoperoxidase studies, the renal tubules and glomerular mesangium showed an increased expression of transforming growth factor β(1)(TGF-β(1)). The expression of megalin was decreased by immunoperoxidase and the cytoplasm showed a granular pattern of megalin expression by immunofluorescence techniques. Western blot analysis performed in the renal cortex from sStx2-treated and control rats using anti-nephrin and anti-podocalyxin antibodies showed a decreased expression of these proteins. We suggest that the alterations in slit diaphragm proteins and megalin expression could be related to the development of microalbuminuria in response to lethal doses of Stx2.

No MeSH data available.


Related in: MedlinePlus

Megalin immunodetection. sStx2-treated rats showing decreased expression of megalin in proximal tubules (A and B) (black arrows), (C) (white arrow); (D–F), control rats; (G–I), negative controls without primary antibody; (C, F and H), immunofluorescence; (A, B, D, E, and G), immunoperoxidase. (I) the number of tubules positive for megalin by immunoperoxidase were counted and the percentage measured using a grid superimposed on the image. Megalin was significantly decreased with respect to the controls (21.8% ± 4.7% vs 94.2% ± 2.9%; P < 0.01, n = 4).Notes: Magnification for (A, D, F, G and H) at 200×; for (B, C and E) at 400×.Abbreviation: sStx2, supernatant Shiga toxin type 2.
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f3-ijnrd-5-029: Megalin immunodetection. sStx2-treated rats showing decreased expression of megalin in proximal tubules (A and B) (black arrows), (C) (white arrow); (D–F), control rats; (G–I), negative controls without primary antibody; (C, F and H), immunofluorescence; (A, B, D, E, and G), immunoperoxidase. (I) the number of tubules positive for megalin by immunoperoxidase were counted and the percentage measured using a grid superimposed on the image. Megalin was significantly decreased with respect to the controls (21.8% ± 4.7% vs 94.2% ± 2.9%; P < 0.01, n = 4).Notes: Magnification for (A, D, F, G and H) at 200×; for (B, C and E) at 400×.Abbreviation: sStx2, supernatant Shiga toxin type 2.

Mentions: The expression of megalin in sStx2-treated rats was decreased by immunoperoxidase (Figure 3A and B). The cytoplasm showed a granular pattern of megalin expression (Figure 3C) by immunofluorescence techniques.


Microalbuminuria and early renal response to lethal dose Shiga toxin type 2 in rats.

Ochoa F, Oltra G, Gerhardt E, Hermes R, Cohen L, Damiano AE, Ibarra C, Lago NR, Zotta E - Int J Nephrol Renovasc Dis (2012)

Megalin immunodetection. sStx2-treated rats showing decreased expression of megalin in proximal tubules (A and B) (black arrows), (C) (white arrow); (D–F), control rats; (G–I), negative controls without primary antibody; (C, F and H), immunofluorescence; (A, B, D, E, and G), immunoperoxidase. (I) the number of tubules positive for megalin by immunoperoxidase were counted and the percentage measured using a grid superimposed on the image. Megalin was significantly decreased with respect to the controls (21.8% ± 4.7% vs 94.2% ± 2.9%; P < 0.01, n = 4).Notes: Magnification for (A, D, F, G and H) at 200×; for (B, C and E) at 400×.Abbreviation: sStx2, supernatant Shiga toxin type 2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3278253&req=5

f3-ijnrd-5-029: Megalin immunodetection. sStx2-treated rats showing decreased expression of megalin in proximal tubules (A and B) (black arrows), (C) (white arrow); (D–F), control rats; (G–I), negative controls without primary antibody; (C, F and H), immunofluorescence; (A, B, D, E, and G), immunoperoxidase. (I) the number of tubules positive for megalin by immunoperoxidase were counted and the percentage measured using a grid superimposed on the image. Megalin was significantly decreased with respect to the controls (21.8% ± 4.7% vs 94.2% ± 2.9%; P < 0.01, n = 4).Notes: Magnification for (A, D, F, G and H) at 200×; for (B, C and E) at 400×.Abbreviation: sStx2, supernatant Shiga toxin type 2.
Mentions: The expression of megalin in sStx2-treated rats was decreased by immunoperoxidase (Figure 3A and B). The cytoplasm showed a granular pattern of megalin expression (Figure 3C) by immunofluorescence techniques.

Bottom Line: Approximately 2%-4% of patients die during the acute phase, and one-third of the 96% who survive are at risk of chronic renal sequelae.In immunoperoxidase studies, the renal tubules and glomerular mesangium showed an increased expression of transforming growth factor β(1)(TGF-β(1)).The expression of megalin was decreased by immunoperoxidase and the cytoplasm showed a granular pattern of megalin expression by immunofluorescence techniques.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisiologia, Facultad de Medicina UBA, Buenos Aires, Argentina.

ABSTRACT
In Argentina, hemolytic uremic syndrome (HUS) constitutes the most frequent cause of acute renal failure in children. Approximately 2%-4% of patients die during the acute phase, and one-third of the 96% who survive are at risk of chronic renal sequelae. Little information is available about the direct effect of Shiga toxin type 2 (Stx2) on the onset of proteinuria and the evolution of toxin-mediated glomerular or tubular injury. In this work, rats were injected intraperitoneally with recombinant Escherichia coli culture supernatant containing Stx2 (sStx2; 20 μg/kg body weight) to induce HUS. Functional, immunoblotting, and immunohistochemistry studies were carried out to determine alterations in slit diaphragm proteins and the proximal tubule endocytic system at 48 hours post-inoculation. We detected a significant increase in microalbuminuria, without changes in the proteinuria values compared to the control rats. In immunoperoxidase studies, the renal tubules and glomerular mesangium showed an increased expression of transforming growth factor β(1)(TGF-β(1)). The expression of megalin was decreased by immunoperoxidase and the cytoplasm showed a granular pattern of megalin expression by immunofluorescence techniques. Western blot analysis performed in the renal cortex from sStx2-treated and control rats using anti-nephrin and anti-podocalyxin antibodies showed a decreased expression of these proteins. We suggest that the alterations in slit diaphragm proteins and megalin expression could be related to the development of microalbuminuria in response to lethal doses of Stx2.

No MeSH data available.


Related in: MedlinePlus