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This Article Full Text Full Text (PDF) All Versions of this Article: 294/6/F1473    most recent 00036.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Wang, W. Articles by Schrier, R. W. PubMed PubMed Citation Articles by Wang, W. Articles by Schrier, R. W.

Role of AQP1 in endotoxemia-induced acute kidney injury

¹Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado; and ²Department of Pathology, Dubrava University Hospital, Zagreb, Croatia

Submitted 22 January 2008 ; accepted in final form 14 April 2008

The effect of endotoxemia (lipopolysaccharide, 2.5 mg/kg ip) was investigated in aquaporin (AQP) 1 knockout (KO) compared with wild-type (WT) mice. At baseline, KO mice exhibited higher water intake (WI) and urine output (UO). After endotoxemia, WI and UO remained higher in the KO than WT mice, and urine osmolality was lower. The higher serum osmolality in AQP1-KO mice during endotoxemia was associated with higher AQP2 (133 ± 8 vs. 100 ± 3%, P < 0.01), AQP3 (140 ± 8 vs. 100 ± 4%, P < 0.001) and Na⁺-K⁺-2Cl^– cotransporter type 2 (NKCC2; 152 ± 14 vs. 100 ± 15%, P < 0.05) expression than that in WT mice. These responses during endotoxemia in the AQP1-KO mice compared with WT were associated with lower glomerular filtration rate (GFR) (69 ± 8 vs. 96 ± 8 ml/min, P < 0.05) and renal blood flow (0.77 ± 0.1 vs. 1.01 ± 0.1 ml/min, P < 0.01). Urinary sodium excretion and fractional sodium excretion were higher in KO compared with WT mice in endotoxemia and were accompanied by more severe tubular injury. With water repletion and comparable serum osmolalities, GFR was still lower in KO (57 ± 13 vs. 120 ± 6 ml/min, P < 0.01) compared with WT during endotoxemia. The abundance of AQP2 and AQP3 protein in KO mice was not different from WT mice; however, NKCC2, Na⁺/H⁺ exchanger type 3, and fractional sodium excretion remained higher in KO compared with WT. Thus the polyuria in AQP1-KO mice does not protect against endotoxemia-induced acute kidney injury but rather absence of AQP1 predisposed to enhanced endotoximic renal injury.

lipopolysaccharide; sepsis; glomerular filtration rate; polyuria; aquaporin-1