This study explores the hypothesis that the inflammatory response induced by administration of lipopolysaccharide (LPS) exacerbates brain edema in cirrhotic rats; and if so whether this is associated with altered brain metabolism of ammonia or anatomical disturbance of the blood-brain barrier. Adult Sprague-Dawley rats 4 weeks after bile duct ligation (BDL)/ Sham-operation, or naïve rats fed a hyperammonemic diet (HD), were injected with LPS (0.5 mg/kg, intraperitoneally) or saline, and killed 3 hours later. LPS administration increased brain water in HD, BDL, and sham-operated groups significantly (P < 0.05), but this was associated with progression to pre-coma stages only in BDL rats. LPS induced cytotoxic brain swelling and maintained anatomical integrity of the blood-brain barrier. Plasma/brain ammonia levels were higher in HD and BDL rats than in sham-operated controls and did not change with LPS administration. Brain glutamine/myoinositol ratio was increased in the HD group but reduced in the BDL animals. There was a background pro-inflammatory cytokine response in the brains of cirrhotic rats, and plasma/brain tumor necrosis factor alpha (TNF-␣) and IL-6 significantly increased in LPS-treated animals. Plasma nitrite/nitrate levels increased significantly in LPS groups compared with non-LPS controls; however, frontal cortex nitrotyrosine levels only increased in the BDL ؉ LPS rats (P < 0.005 versus BDL controls). Conclusion: Injection of LPS into cirrhotic rats induces pre-coma and exacerbates cytotoxic edema because of the synergistic effect of hyperammonemia and the induced inflammatory response. Although the exact mechanism of how hyperammonemia and LPS facilitate cytotoxic edema and pre-coma in cirrhosis is not clear, our data support an important role for the nitrosation of brain proteins. (HEPATOLOGY 2007;45: 1517-1526

Hemoproteins, hemoglobin and myoglobin, once released from cells can cause severe oxidative damage as a consequence of heme redox cycling between ferric and ferryl states that generates radical species that induce lipid peroxidation. We demonstrate in vitro that acetaminophen inhibits hemoprotein-induced lipid peroxidation by reducing ferryl heme to its ferric state and quenching globin radicals. Severe muscle injury (rhabdomyolysis) is accompanied by the release of myoglobin that becomes deposited in the kidney, causing renal injury. We previously showed in a rat model of rhabdomyolysis that redox cycling between ferric and ferryl myoglobin yields radical species that cause severe oxidative damage to the kidney. In this model, acetaminophen at therapeutic plasma concentrations significantly decreased oxidant injury in the kidney, improved renal function, and reduced renal damage. These findings also provide a hypothesis for potential therapeutic applications for acetaminophen in diseases involving hemoproteinmediated oxidative injury.isoprostanes | oxidative damage | hemoglobin | myoglobin

We conducted a randomized controlled trial using mobile health technology in an ethnically diverse sample of 137 patients with complicated diabetes. Patients in the intervention group (n = 72) were trained to measure their blood glucose with a sensor which transmitted the readings to a mobile phone via a Bluetooth wireless link. Clinicians were then able to examine and respond to the readings which were viewed with a web-based application. Patients in the control arm of the study (n = 65) did not transmit their readings and received care with their usual doctor in the outpatient and/or primary care setting. The mean follow-up period was 9 months in each group. The default rate was higher in the patients in the intervention arm due to technical problems. In an intention-to-treat analysis there were no differences in HbA(1c) between the intervention and control groups. In a sub-group analysis of the patients who completed the study, the telemonitoring group had a lower HbA(1c) than those in the control group: 7.76% and 8.40%, respectively (P = 0.06).

Sepsis is a common complication of cirrhosis with a high mortality. In this study, we have investigated some of the pathways that may be involved in tissue injury and death. Bile duct-ligated (BDL) cirrhotic and control rats were challenged with lipopolysaccharide (LPS). Sensitivity to LPS was markedly enhanced in the BDL group, and was associated with increased liver injury and mortality. There was a 5-fold constitutive activation of nuclear factor B (NFB) in the liver of BDL rat controls (P F .001), and this was activated further, but to a similar extent, in the liver of both sham and BDL rats after injection of LPS. Plasma tumor necrosis factor ␣ (TNF-␣) increased more markedly in the BDL cirrhotic rats (2,463 ؎ 697 pg/mL in BDL rats versus 401 ؎ 160 pg/mL in the controls at 3 hours; P F .01). Plasma nitrite/nitrate concentrations were increased in the BDL controls at baseline, and increased further after LPS (P F .05), but did not differ from sham controls at 6 hours. Plasma F 2 -isoprostanes increased 6-fold in the cirrhotic rats and 2-fold in the controls (P F .01) indicative of lipid peroxidation. Esterified F 2 -isoprostanes in the liver increased 2-to 3-fold at 1 hour in control and BDL rats, but returned to baseline levels by 3 hours. Esterified F 2 -isoprostanes in the kidney increased by 2-fold in the BDL rats after LPS administration, but remained unchanged in sham controls. We conclude that there is a marked increase in sensitivity to LPS in BDL cirrhotic rats. This is associated with an enhanced TNF-␣ response and increased lipid peroxidation. These may be directly and causally related to mortality. (HEPATOLOGY 1999;30:1198-1205.)Sepsis and associated endotoxemia occur in approximately 40% of hospitalized patients with cirrhosis and is a major cause of death.

Background and aims: Renal failure occurs in approximately 55% of patients with acute liver failure. We have previously shown that plasma endothelin 1 concentrations are elevated in patients with acute liver failure and the hepatorenal syndrome. There are few reported satisfactory animal models of liver failure together with functional renal failure. In this study, a rat model of acute liver failure induced by galactosamine that also develops renal failure was first characterised. This model was used to investigate the hypothesis that endothelin 1 is an important mediator involved in the pathogenesis of renal impairment that occurs in acute liver failure. Methods: Acute liver failure was induced in male Sprague-Dawley rats by intraperitoneal injection of galactosamine together with treatment with the endothelin receptor antagonist Bosentan. Twenty four hour urine collections were made using a metabolic cage. Renal blood flow was measured in anaesthetised animals. Results: This model developed renal failure and liver failure in the absence of any significant renal pathology, and with an accompanying fall in renal blood flow. Plasma concentrations of endothelin 1 were increased twofold following the onset of liver and renal failure (p<0.05), and there was significant upregulation of the endothelin receptor A (ET A ) in the renal cortex (p<0.05). Administration of Bosentan prevented the development of renal failure when given before or 24 hours after the onset of liver injury (p<0.05) but had no effect on liver injury itself, or on renal blood flow. Conclusions: This study demonstrates that this animal model has many of the features needed to be regarded as a model of renal failure that occurs in acute liver failure. The observation that plasma levels of endothelin 1 and ET A receptors are increased and upregulated, and that renal failure is prevented by an endothelin antagonist supports the hypothesis originally put forward that ET A is important in the pathogenesis of renal failure that occurs in patients with acute liver failure.

Partial portal vein ligation (PPVL) leads to the development of a hyperdynamic circulation. It is associated with elevated levels of tumor necrosis factor (TNF-␣) and nitric oxide (NO) production, both of which can result in oxidant injury. In this study, we have investigated whether PPVL is associated with the development of oxidative stress, by measuring urinary F 2 -isoprostanes. In addition, we have examined whether N-acetylcysteine (NAC) can ameliorate oxidant injury and prevent the development of the hyperdynamic circulation. Urinary excretion of F 2 -isoprostanes increased sixfold following PPVL together with a significant increase in plasma nitrite and nitrate. Treatment with NAC inhibited the formation of F 2 -isoprostanes as well as the increase in plasma nitrite and nitrate. Hemodynamic studies in anesthetized rats showed that following PPVL, cardiac output and portal pressure increased, and systemic vascular resistance decreased, consistent with the development of a hyperdynamic circulation. These changes were prevented by chronic administration of NAC. We conclude that NAC prevents the development of the hyperdynamic circulation and that the formation of reactive oxygen species may be important in the pathogenesis of these hemodynamic changes. (HEPATOLOGY 1998;28:689-694.)

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Chronic bile duct ligation is associated with the development of oxidant injury, biliary cirrhosis, portal hypertension, and a hyperdynamic circulation. We have previously demonstrated that the hyperdynamic circulation in the partial portal vein-ligated rat can be prevented by the administration of N-acetylcysteine. To extend these findings, we have examined the effect of lipoic acid, a thiolcontaining antioxidant, on hemodynamics, oxidative stress, and nitric oxide (NO) production in bile duct-ligated (BDL) cirrhotic rats. Lipoic acid was given continuously in drinking water to normal and BDL rats; control rats received ordinary drinking water, and animals were studied at 24 days following surgery. Lipoic acid prevented the development of the hyperdynamic circulation (cardiac index [CI]: 15.7 ؎ 2.0 vs. 29.5 ؎ 2.1 mL и min ؊1 и 100 g ؊1 ; P F .05) and significantly attenuated the rise in portal pressure (PP) (12.7 ؎ 0.8 vs. 15.2 ؎ 0.5 mm Hg; P F .05). Hepatic nitric oxide synthase (NOS) activity and plasma nitrite/nitrate concentration increased significantly following bile duct ligation, and both of these were prevented by lipoic acid. Lipoic acid had no effect on the biochemical or histological parameters of liver function in the cirrhotic group. We conclude that lipoic acid prevents the development of the hyperdynamic circulation in the rat model of biliary cirrhosis, and that this is associated with decreased synthesis of NO. (HEPATOLOGY 1999;29:1358-1363.)Chronic bile duct ligation leads to biliary cirrhosis within 3 to 4 weeks in the rat. Following bile duct ligation, there is cholestatic liver injury, with depletion of endogenous antioxidants 1,2 and increased levels of markers of oxidant injury. 1,3 This is followed by the development of ductular proliferation and fibrosis, and is associated with the development of portal hypertension and a hyperdynamic circulation, characterized by a high cardiac output and low systemic vascular resistance. Previous studies have shown protective effects of antioxidants on liver damage in this model as assessed by biochemical and histological parameters, 1,4,5 and also a moderate reduction in portal pressure (PP). 6 The hyperdynamic circulation that occurs in this model following the development of biliary cirrhosis is central to the development of many of the complications that occur in advanced liver disease, including ascites and renal dysfunction, portal hypertension, and the hepatopulmonary syndrome. We previously demonstrated that chronic administration of N-acetylcysteine prevents development of the hyperdynamic circulation following partial portal vein ligation 7 and is accompanied by decreased plasma concentrations of the metabolic products of nitric oxide (NO), nitrite and nitrate. However, in the above study, N-acetylcysteine was given twice daily by intraperitoneal injection, because it has a limited oral bioavailability. Therefore, to extend these studies to a cirrhotic model, we have used the sodium salt of lipoic acid, a thiol-containing antioxidant with g...