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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

Nephrin and PC immunodetection. (A) nephrin expression (white arrows) in control rats; (B) sStx2-treated rats showing a decreased expression of nephrin (white arrowhead); (C) PC expression in control rats (white arrowhead); (D) a marked decreased expression of PC in sStx2-treated rats. The number of positive marks of nephrin and PC was counted in ten fields of 200× using a grid superimposed on the image. (E) Expressions of nephrin (176.33 ± 16.6 vs 32.16 ± 10.6; P < 0.01, n = 6) and (F) PC (122.16 ± 10.6 vs 19.16 ± 7.9; P < 0.01, n = 6) were significantly decreased with respect to the controls.Note: Magnification for (A–D) at 200×.Abbreviations: sStx2, supernatant Shiga toxin type 2; PC, podocalyxin.
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f4-ijnrd-5-029: Nephrin and PC immunodetection. (A) nephrin expression (white arrows) in control rats; (B) sStx2-treated rats showing a decreased expression of nephrin (white arrowhead); (C) PC expression in control rats (white arrowhead); (D) a marked decreased expression of PC in sStx2-treated rats. The number of positive marks of nephrin and PC was counted in ten fields of 200× using a grid superimposed on the image. (E) Expressions of nephrin (176.33 ± 16.6 vs 32.16 ± 10.6; P < 0.01, n = 6) and (F) PC (122.16 ± 10.6 vs 19.16 ± 7.9; P < 0.01, n = 6) were significantly decreased with respect to the controls.Note: Magnification for (A–D) at 200×.Abbreviations: sStx2, supernatant Shiga toxin type 2; PC, podocalyxin.

Mentions: The immunofluorescence studies of glomeruli from sStx2-treated rats at 48 hours showed a decreased expression of nephrin (Figure 4B) and PC in podocytes (Figure 4D). Morphometric quantification detected a significant decrease in the expression of nephrin (32.16 ± 10.6 vs 176.33 ± 16.6; P < 0.01, n = 6) and PC (19.16 ± 7.9 vs 122.16 ± 10.6; P < 0.01, n = 6) with respect to the controls (Figure 4E and F).


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)

Nephrin and PC immunodetection. (A) nephrin expression (white arrows) in control rats; (B) sStx2-treated rats showing a decreased expression of nephrin (white arrowhead); (C) PC expression in control rats (white arrowhead); (D) a marked decreased expression of PC in sStx2-treated rats. The number of positive marks of nephrin and PC was counted in ten fields of 200× using a grid superimposed on the image. (E) Expressions of nephrin (176.33 ± 16.6 vs 32.16 ± 10.6; P < 0.01, n = 6) and (F) PC (122.16 ± 10.6 vs 19.16 ± 7.9; P < 0.01, n = 6) were significantly decreased with respect to the controls.Note: Magnification for (A–D) at 200×.Abbreviations: sStx2, supernatant Shiga toxin type 2; PC, podocalyxin.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3278253&req=5

f4-ijnrd-5-029: Nephrin and PC immunodetection. (A) nephrin expression (white arrows) in control rats; (B) sStx2-treated rats showing a decreased expression of nephrin (white arrowhead); (C) PC expression in control rats (white arrowhead); (D) a marked decreased expression of PC in sStx2-treated rats. The number of positive marks of nephrin and PC was counted in ten fields of 200× using a grid superimposed on the image. (E) Expressions of nephrin (176.33 ± 16.6 vs 32.16 ± 10.6; P < 0.01, n = 6) and (F) PC (122.16 ± 10.6 vs 19.16 ± 7.9; P < 0.01, n = 6) were significantly decreased with respect to the controls.Note: Magnification for (A–D) at 200×.Abbreviations: sStx2, supernatant Shiga toxin type 2; PC, podocalyxin.
Mentions: The immunofluorescence studies of glomeruli from sStx2-treated rats at 48 hours showed a decreased expression of nephrin (Figure 4B) and PC in podocytes (Figure 4D). Morphometric quantification detected a significant decrease in the expression of nephrin (32.16 ± 10.6 vs 176.33 ± 16.6; P < 0.01, n = 6) and PC (19.16 ± 7.9 vs 122.16 ± 10.6; P < 0.01, n = 6) with respect to the controls (Figure 4E and F).

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