Biomarkers of oxidative stress study V: ozone exposure of rats and its effect on lipids, proteins, and DNA in plasma and urine.

Ozone exposure effect on free radical-catalyzed oxidation products of lipids, proteins, and DNA in the plasma and urine of rats was studied as a continuation of the international Biomarker of Oxidative Stress Study (BOSS) sponsored by NIEHS/NIH. The goal was to identify a biomarker for ozone-induced oxidative stress and to assess whether inconsistent results often reported in the literature might be due to the limitations of the available methods for measuring the various types of oxidative products. The time- and dose-dependent effects of ozone exposure on rat plasma lipid hydroperoxides, malondialdehyde, F2-isoprostanes, protein carbonyls, methionine oxidation, and tyrosine- and phenylalanine oxidation products, as well as urinary malondialdehyde and F2-isoprostanes were investigated with various techniques. The criterion used to recognize a marker in the model of ozone exposure was that a significant effect could be identified and measured in a biological fluid seen at both doses at more than one time point. No statistically significant differences between the experimental and the control groups at either ozone dose and time point studied could be identified in this study. Tissue samples were not included. Despite all the work accomplished in the BOSS study of ozone, no available product of oxidation in biological fluid has yet met the required criteria of being a biomarker. The current negative findings as a consequence of ozone exposure are of great importance, because they document that in complex systems, as the present in vivo experiment, the assays used may not provide meaningful data of ozone oxidation, especially in human studies.

Biomarkers of Oxidative Stress Study IV: ozone exposure of rats and its effect on antioxidants in plasma and bronchoalveolar lavage fluid.

The objective of this study was to determine whether acutely exposing rats to ozone would result in the loss of antioxidants from plasma and bronchoalveolar lavage fluid (BALF). Additional goals were to compare analyses of the same antioxidant concentration between different laboratories, to investigate which methods have the sensitivity to detect decreased levels of antioxidants, and to identify a reliable measure of oxidative stress in ozone-exposed rats. Male Fisher rats were exposed to either 2.0 or 5.0 ppm ozone inhalation for 2h. Blood plasma and BALF samples were collected 2, 7, and 16 h after the exposure. It was found that ascorbic acid in plasma collected from rats after the higher dose of ozone was lower at 2h, but not later. BALF concentrations of ascorbic acid were decreased at both 2 and 7h postexposure. Tocopherols (α, δ, γ), 5-nitro-γ-tocopherol, tocol, glutathione (GSH/GSSG), and cysteine (Cys/CySS) were not decreased, regardless of the dose or postexposure time point used for sample collection. Uric acid was significantly increased by the low dose at 2h and the high dose at the 7h point, probably because of the accumulation of blood plasma in the lung from ozone-increased alveolar capillary permeability. We conclude that measurements of antioxidants in plasma are not sensitive biomarkers for oxidative damage induced by ozone and are not a useful choice for the assessment of oxidative damage by ozone in vivo.

Retroperitoneal varices presenting as an adrenal pseudotumor in a cirrhotic patient.

Herein is reported a case of a putative tumor of the left adrenal gland found incidentally during the workup of a cirrhotic patient with portal hypertension. This mass manifested vascular enhancement and other features of an adenoma both on computed tomography (CT) and magnetic resonance imaging (MRI) scans. Additional workup revealed elevated salivary cortisol and plasma aldosterone levels. A proposed biopsy of this mass was deferred because of an episode of variceal bleeding that required placement of a transjugular intrahepatic portosystemic shunt (TIPS). Post TIPS placement, repeat CT and MRI scans showed that the mass had disappeared, indicating that this pseudotumor was, in fact, a knot of peri-adrenal varices, which was now decompressed. In this report, the anatomic and pathologic basis of peri-adrenal varices in a patient with portal hypertension is discussed, as well as the ability of current imaging studies at establishing this diagnosis. Liver disease may cause abnormalities in endocrine function, which make this diagnosis difficult.

Recombinant human factor VIIa-induced alterations in tissue factor and thrombomodulin in patients with advanced liver cirrhosis.

BACKGROUND: Recombinant human factor VIIa (rhFVIIa) is used to treat hemophilia and occasionally individuals with liver disease. The aim of the present study was to investigate the consequences of rhFVIIa in individuals with advanced liver disease in an attempt to understand the mechanism of action of rhFVIIa in this unique population. METHODS: Levels of plasma tissue factor, plasminogen activator inhibitor-1, tissue factor pathway inhibitor, fibrin split products, D-dimers and free thrombomodulin were measured following the administration of rhFVIIa in 17 subjects. The results were compared to normal controls. RESULTS: The prothrombin time declined from 20.2 +/- 2.8 s to 14.3 +/- 3.9 s (P < 0.01). No change in the activated partial thromboplastin time occurred. A 15.6% reduction in thrombomodulin was observed (P < 0.05). A mean 75.2% reduction in plasma tissue factor occurred (P < 0.01). Tissue factor pathway inhibitor levels declined to less than the control value (P < 0.05). No changes in plasminogen activator inhibitor-1, fibrin split products or D-dimer levels occurred. CONCLUSIONS: These data demonstrate that rhFVIIa administration to individuals with liver disease results in (i) a transient improvement in the prothrombin time; (ii) no change in the activated partial thromboplastin time; and (iii) a marked reduction in the levels of thrombomodulin and tissue factor. These data suggest that rhFVIIa binds tissue factor and enhances tissue factor and thrombomodulin clearance from the circulation.

Amelioration of hypertrophic cardiomyopathy using nonsurgical septal ablation in a cirrhotic patient prior to liver transplantation.

A 53-year-old male with hepatitis C cirrhosis, who had been refused liver transplantation because of hypertrophic cardiomyopathy (HC), underwent nonsurgical septal ablation using alcohol with resolution of his ventricular outflow obstruction. This patient was able to subsequently undergo a successful deceased donor liver transplantation. This is the first reported case of alcohol induced septal ablation being performed in a cirrhotic patient with HC. Such nonsurgical procedures may be attractive in cirrhotic patients who are refused access to liver transplantation because of high surgical risk.

Platelet sparing effect of COX II inhibition used with pegylated interferon alfa-2a for the treatment of chronic hepatitis C: a short term pilot study.

The role of a cyclooxygenase (COX) II inhibitor in reducing microvascular inflammation and the platelet count associated with interferon (IFN) plus ribavirin therapy of chronic hepatitis C (HCV) was assessed. Three plasma mediators (biomarkers) associated with platelet activation, inflammation and fibrosis were measured. Eighteen IFN naïve patients were studied. Nine were treated with pegylated IFN alfa-2a (PEG-IFN alpha-2a) plus ribavirin and rofecoxib; nine were treated with PEG-IFN alpha-2a plus ribavirin. A complete blood count, liver panel and HCV-RNA were assayed weekly. Human soluble P-selectin (hs-P-selectin), human interleukin-8 (IL-8), human interleukin-13 (IL-13) and human thrombopoietin (TPO) were assayed at 4 week intervals. The COX II inhibitor reduced the platelet reduction experienced with PEG-IFN alpha-2a treatment of HCV despite a reduction in the plasma TPO level. Hs-P-selectin was increased in both groups. In contrast, human IL-8 levels declined to undetectable levels in virologic responders. Similarly, human IL-13 levels declined with therapy (P < 0.001). These data suggest that: (1) a COX II inhibition is associated with an increase in the platelet count despite a reduction in the TPO level; (2) human IL-8 and human IL-13 but not hs-P-selectin levels decline in those who experience an early virologic response.

Coagulation and fibrinolysis in individuals with advanced liver disease.

An overview of normal coagulation and fibrinolysis is presented. The abnormalities of coagulation and fibrinolysis seen in individuals with advanced liver disease is reviewed. The necessary steps in the management of bleeding in patients with advanced liver disease is outlined. Finally those liver diseases associated with vascular thrombosis are identified.

Splenic embolization in a Jehovah's Witness: role of recombinant human factor VIIa.

A case of a 50-year-old Jehovah's Witness with cryptogenic cirrhosis, severe portal hypertension and a coagulopathy, who underwent splenic embolization to improve the platelet count after receiving recombinant human Factor VIIa, is reported. Following the infusion of recombinant human Factor VIIa, the coagulopathy was rapidly corrected and it became possible to safely embolize her spleen. The changes in prothrombin time, international normalized ratio and activated partial thromboplastin time as well as thrombomodulin, tissue factor and plasminogen activator inhibitor after the infusion are presented. As a result of the splenic embolization, her platelet count normalized and she has been listed for liver transplantation.

Hemostatic modulation with the liver dialysis device in humans with advanced liver disease.

BACKGROUND/AIMS: To determine the alterations in coagulation and fibrinolysis occurring in patients treated with the liver dialysis device. METHODOLOGY: Patients with advanced liver disease treated with the liver dialysis device were studied immediately before and after the liver dialysis device treatment. SETTING: A university hospital intensive care unit. PATIENTS: Thirteen consecutive patients with advanced liver disease being evaluated for or awaiting liver transplantation. INTERVENTION: 4-6 hours of liver dialysis treatment for management of hepatic encephalopathy. OUTCOME MEASURES: A panel of coagulation and anticoagulation factors, as well as fibrinolytic and anti-fibrinolytic factors plus measures of activation of inflammation and soluble adhesion factors. RESULTS: The liver dialysis device used was found to be associated with activation of both coagulation and fibrinolytic pathways, activation of inflammation reactants, and an increase in sL-selectin levels. CONCLUSIONS: Liver dialysis device activates both coagulant and fibrinolytic pathways, activates inflammatory response, but these responses are limited to the vascular compartment by an increase in sL-selectin levels.