Acute renal failure (ARF), characterized by sudden loss of the ability of the kidneys to excrete wastes, concentrate urine, conserve electrolytes, and maintain fluid balance, is a frequent clinical problem, particularly in the intensive care unit, where it is associated with a mortality of between 50% and 80%. In this review, the epidemiology and pathophysiology of ARF are discussed, including the vascular, tubular, and inflammatory perturbations. The clinical evaluation of ARF and implications for potential future therapies to decrease the high mortality are described. Science in Medicine

The pathogenesis of septic acute renal failure (ARF) involves systemic vasodilation with compensatory upregulation of vasoconstrictors. This can lead to renal vasoconstriction and ARF. Heme oxygenase (HO) is the rate-limiting step in heme metabolism and produces carbon monoxide (CO) and biliverdin. HO-1 is an inducible form of the enzyme and is expressed in response to cell injury. It was hypothesized in endotoxemia, induction of HO-1 would lead to increased production of the vasodilator CO, lower blood pressure, and decrease renal function. The role of HO-1 was therefore examined in a mouse model of endotoxemia. One group of mice received LPS alone and were compared with mice that received LPS in addition to an inhibitor of HO-1, zinc protoporphyrin (ZnPP). Treatment of mice with LPS resulted in significant increases in the protein expression of HO-1 compared with controls treated with vehicle. Immunohistochemical analysis localized this upregulation to both the proximal and distal tubules as well as the vasculature. Hemodynamic studies were performed during endotoxemia and the mean arterial pressure (MAP) was found to be significantly higher in the HO-1 inhibitor-treated compared with vehicle-treated mice (78 +/- 3 vs. 64 +/- 2 mmHg, P < 0.01). It was found that the inhibitor group had higher renal blood flows (RBF) also during endotoxemia (1.8 +/- 0.2 vs. 0.68 +/- 0.1 ml/min, P < 0.01). Furthermore, when renal vascular resistance (RVR) was calculated, there was a significant decrease in RVR in the inhibitor group (43.5 +/- 3.4 vs. 95.9 +/- 11.3 mmHg.ml(-1).min(-1), P < 0.01). In concert with the hemodynamic data, glomerular filtration rate (GFR), as measured by inulin clearance, was higher in the HO inhibitor compared with the vehicle controls during endotoxemia (111.5 +/- 19.5 vs. 66.0 +/- 3.5 microl/min, P < 0.05). In summary, during endotoxemia ARF, inhibiting HO-1 with ZnPP resulted in the protection of renal function. The renal protection was associated with significantly improved systemic hemodynamics, less renal vasoconstriction, and a higher GFR.

This chapter contains sections titled: Prevalence Glomerular pathology in cirrhosis The association between cirrhosis and glomerular IgA deposition Hepatitis C virus and renal disease Hepatitis B virus and renal disease Liver disease and renal tubular acidosis

Acute renal failure (ARF), characterized by sudden loss of the ability of the kidneys to excrete wastes, concentrate urine, conserve electrolytes, and maintain fluid balance, is a frequent clinical problem, particularly in the intensive care unit, where it is associated with a mortality of between 50% and 80%. In this review, the epidemiology and pathophysiology of ARF are discussed, including the vascular, tubular, and inflammatory perturbations. The clinical evaluation of ARF and implications for potential future therapies to decrease the high mortality are described.

It is known that, among human patients with sepsis, acute renal failure (ARF) dramatically increases mortality rates to 50 to 80%. However, the pathogenesis of septic ARF is not fully understood. An increase in endotoxin-induced mortality rates for leptin-deficient ob/ob mice was recently demonstrated. In comparison with ob/ob mice, db/db mice, which are deficient in the long isoforms of leptin receptors (Ob/Rb), demonstrate lower mortality rates after exposure to the endotoxin LPS. In db/db mice, mRNA for the short isoforms of leptin receptors is constitutively expressed in the kidney, lung, liver, and macrophages. It is known that plasma leptin levels increase in rodents after exposure to LPS, and this was demonstrated for db/db mice. Because ob/ob and db/db mice are both obese, factors other than obesity must be involved in the increased mortality rates for ob/ob mice. In this study, the hypothesis that the short forms of leptin receptors might offer protection against endotoxin-induced lethality at least in part by providing protection against ARF was examined. Serum leptin levels were significantly increased with LPS treatment in wild-type and db/db mice but not ob/ob mice. GFR decreased significantly 16 h after the homozygous ob/ob mice received intraperitoneal injections of 0.3 mg/kg LPS (0.37 +/- 0.04 ml/min per g kidney versus 0.83 +/- 0.06 ml/min per g kidney, n = 6, P < 0.01); the mean arterial pressure (MAP) remained unchanged. For ob/ob littermates (+/?ob), there was no significant change in either MAP or GFR when the mice were challenged with the same time interval (16 h) and dose of LPS. In contrast to ob/ob mice, there was no significant change in GFR or MAP when homozygous db/db mice or their littermates received injections of an even higher dose of LPS (0.4 mg/kg). Mouse recombinant leptin had no effect on GFR when ob/ob mice received 0.3 mg/kg LPS injections. However, renal function (serum creatinine levels, 0.4 +/- 0.1 mg/dl versus 0.9 +/- 0.1 mg/dl, P < 0.01) and MAP (68 +/- 4 mmHg versus 51 +/- 2 mmHg, n = 6, P < 0.01) were significantly improved with leptin replacement when the ob/ob mice developed hypotensive ARF with a higher dose of LPS (0.5 mg/kg). In summary, the previously reported increased susceptibility to LPS of ob/ob mice, compared with db/db mice, may be attributable at least in part to increased susceptibility to ARF.