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Critical Care and Emergency Medicine - Infectious Diseases - Nephrology - Physiology


Renal Involvement in Leptospirosis: The Effect of Glycolipoprotein on Renal Water Absorption
Published: Wednesday, June 06, 2012
Author: Katia Regina Cesar et al.

by Katia Regina Cesar, Eliete Caló Romero, Ana Carolina de Bragança, Roberta Morozetti Blanco, Patrícia Antonia Estima Abreu, Antonio José Magaldi

Background

Leptospirotic renal lesions frequently produce a polyuric form of acute kidney injury with a urinary concentration defect. Our study investigated a possible effect of the glycolipoprotein, (GLPc) extracted from L. interrogans, on vasopressin (Vp) action in the guinea pig inner medullary collecting duct (IMCD).

Methods

The osmotic water permeability (Pf µm/s) was measured by the microperfusion in vitro technique. AQP2 protein abundance was determined by Western Blot. Three groups were established for study as follows: Group I, IMCD from normal (ngp, n?=?5) and from leptospirotic guinea-pigs (lgp-infected with L. interrogans serovar Copenhageni, GLPc, n?=?5); Group II, IMCD from normal guinea-pigs in the presence of GLPc (GLPc group, n?=?54); Group III, IMCD from injected animals with GLPc ip (n?=?8).

Results

In Group I, Pfs were: ngp- 61.8±22.1 and lgp- 8.8±12.4, p<0.01 and the urinary osmolalities were: lgp-735±64 mOsm/Kg and ngp- 1,632±120 mOsm/Kg. The lgp BUN was higher (176±36 mg%) than the ngp (56±9 mg%). In Group II, the Pf was measured under GLPc (250 µg/ml) applied directly to the bath solution of the microperfused normal guinea-pig IMCDs. GLPc blocked Vp (200 pg/ml,n?=?5) action, did not block cAMP (10-4 M,) and Forskolin (Fors- 10-9 M) action, but partially blocked Cholera Toxin (ChT- 10-9 M) action. GLP from L.biflexa serovar patoc (GLPp, non pathogenic, 250 µg) did not alter Vp action. In Group III, GLPc (250 µg) injected intraperitoneally produced a decrease of about 20% in IMCD Aquaporin 2 expression.

Conclusion

The IMCD Pf decrease caused by GLP is evidence, at least in part, towards explaining the urinary concentrating incapacity observed in infected guinea-pigs.

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