Claudio Augusto Marroni

Effects of quercetin on liver damage in rats with carbon tetrachloride-induced cirrhosis.

Flavonoids are reported to exhibit a wide variety of biological effects, including antioxidant and free radical-scavenging activities. Evidence of oxidative reactions is often associated with various chronic disease processes characterized by accumulation of connective tissue. This study was aimed to investigate the protective effects of chronic administration of the flavonoid quercetin (150 μmol/kg body wt/day intraperitoneally) in rats with carbon tetrachloride-induced fibrosis. In animals rendered cirrhotic by administration of carbon tetrachloride for 16 weeks, cell necrosis, fibrosis, and inflammatory infiltration were found. Histological abnormalities were accompanied by a higher hepatic content of collagen and thiobarbituric acid-reactive substances. Expression of inducible nitric oxide synthase (iNOS) was significantly increased in the liver. Treatment with quercetin during 3 weeks improved liver histology and reduced collagen content, iNOS expression, and lipid peroxidation. Those effects were associated with an increased total peroxyl radical-trapping antioxidant capacity of liver. We conclude that quercetin is effective in this model of liver damage.

Effects of Glutamine on Proinflammatory Gene Expression and Activation of Nuclear Factor Kappa B and Signal Transducers and Activators of Transcription in TNBS-induced Colitis

Background: We investigated the effects of glutamine on proinflammatory gene expression and activation of nuclear factor kappa B (NF‐&kgr;B) and signal transducers and activators of transcription (STAT) in a rat model of experimental colitis. Methods: Colitis was induced in male Wistar rats by intracolonic administration of 30 mg of 2,4,6‐trinitrobenzene sulfonic acid (TNBS). Glutamine (25 mg/kg) was given by rectal route daily for 7 days. Results: Glutamine significantly reduced gross damage and histopathological scores and prevented the decrease of anal pressure and the elevated myeloperoxidase activity observed in the colon of animals receiving TNBS. TNBS administration induced a marked increase of vascular cell adhesion molecule (VCAM‐1), inducible nitric oxide synthase (iNOS), and cyclooxygenase‐2 (COX‐2) protein levels. These inflammatory events were associated with increased protein level of NF‐&kgr;B p50 and p65 subunits in the nucleus and significant phosphorylation/degradation of the inhibitor I&kgr;B&agr;. Protein levels of the phosphorylated forms of STAT1, STAT5, and Akt were elevated in animals with colonic damage. All these effects were inhibited by administration of glutamine. Increases in the cytosolic concentration of TBARS and hydroperoxide‐initiated chemiluminescence, markers of oxidative stress, and levels of tumor necrosis factor &agr; (TNF&agr;) and interferon &ggr; (IFN&ggr;) were significantly inhibited at 48 hours of TNBS instillation in glutamine‐treated animals. Conclusions: Inhibition of the expression of proinflammatory mediators that are regulated by the NF‐&kgr;B and STAT signaling pathways contribute to the therapeutical effect of glutamine in the TNBS model of experimental colitis. These effects may be brought about by inhibition of oxidative stress and reduced expression of proinflammatory cytokines.

Nutritional assessment in patients with cirrhosis

CONTEXT Malnutrition in cirrhotic patients with end-stage disease is common, and the degree of nutritional debilitation can play an important role in the pathogenesis of complications and cause a negative impact on prognosis. However, it involves difficulties and controversies regarding the identification of the best nutritional assessment method. OBJECTIVE To identify a method that provides a safe and effective nutritional diagnosis. METHODS Cross-sectional study with 129 cirrhotic patients. Anthropometric measurements, subjective global assessment, hand grip strength and bioelectrical impedance. RESULTS Through phase angle of bioelectrical impedance analysis (BIA) method, significant associations with Child-Pugh (P = 0.008), age group and gender were observed. The ROC (receiver operator characteristic) curve was generated to determine the best cutoff point of the phase angle of cirrhotic patients, serving as one of the reference parameters for the nutritional assessment with bioimpedance in this study, considering the classification through Child-Pugh score as the reference standard for the clinical conditions of patients with cirrhosis. CONCLUSIONS The assessment through bioelectrical impedance presented a statistically significant correlation with Child-Pugh score. The identification of phase angle of 5.44º is the new parameter suggested for the classification of the nutritional conditions of cirrhotic patients.

MELD and other predictors of survival after liver transplantation

Abstract:  Background:  This study examined how reliable is the pre‐transplant model for end‐stage liver disease (MELD) score in predicting post‐transplantation survival and analyzed variables associated with patient survival.

N-Acetylcysteine Effects on Genotoxic and Oxidative Stress Parameters in Cirrhotic Rats with Hepatopulmonary Syndrome

The aim of this study was to evaluate the potential antioxidant effects of N-acetylcysteine in hepatopulmonary syndrome, a complication of cirrhosis, using an experimental model of common bile duct ligation in rats. Male Wistar rats were divided into four experimental groups: CBDL (animals submitted to common bile duct ligation); Sham (animals submitted to simulated common bile duct ligation); Sham + N-acetylcysteine, and CBDL + N-acetylcysteine. N-acetylcysteine (10 mg/kg, intraperitoneally) was administered for 2 weeks starting on day 14 after surgery. Some alterations in the liver integrity were investigated by evaluation of serum enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and arterial blood gases. Lipoperoxidation by thiobarbituric acid-reactive substances assay, superoxide dismutase activity and total nitrates was measured as parameters of oxidative stress, performed on lung homogenates. Micronucleus assay in bone marrow and comet assay in lung, liver and blood were performed to assess the genotoxic effects by oxidative stress. The results showed an improvement in the enzymatic parameters and arterial blood gases, a reduction of lipoperoxidation and in the total nitrates after treatment with N-acetylcysteine. Histological analysis showed vasodilatation in the lung, which was reversed by N-acetylcysteine. Micronuclei frequency and DNA damage in lung and liver were increased in the CBDL group. N-Acetylcysteine caused no genotoxic effect and did not influence the induction of micronucleus in bone marrow and DNA damage in lung and liver. The results suggest protective effects after treatment with N-acetylcysteine in cirrhotic rats with hepatopulmonary syndrome.

Functional status, respiratory muscle strength, and quality of life in patients with cirrhosis

BACKGROUND: Liver diseases are responsible for metabolic disorders and loss of muscle mass and function that affect functional status and quality of life (QoL). OBJECTIVE: To compare exercise capacity, respiratory muscle strength, and QoL in liver transplant candidates with cirrhosis of the following etiologies: hepatitis C virus (HCV), hepatitis B virus (HBV), and alcoholic cirrhosis (AC). METHODS: Cross-sectional study comprising 86 patients divided into three groups: HCV (40 patients), HBV (14 patients), and AC (32 patients). Patients were evaluated using the Six-Minute Walk Test (6MWT), manometry, and the QoL questionnaire SF-36. RESULTS: The AC group showed the lowest performance in the 6MWT (meters) compared to the HBV and HCV groups (373.50±50.48, 464.16±32, and 475.94±27.84, respectively, p=0.001). In the domains of the SF-36, the AC group had lower scores for functional capacity and physical limitations when compared to the HBV and HCV groups (p=0.001). In the comparison of respiratory muscle strength, the AC group had lower MIP (cmH2O) compared to the HBV and HCV groups (-65.54±11.28, -71.61±6.96, -82.44±13.71, respectively, p=0.001). The MEP (cmH2O) in the AC group was also lower than in the HBV and HCV groups (65.13±10.74, 82.44±13.87, 83.44±12.20, respectively, p=0.001). CONCLUSION: The AC group showed worse exercise capacity, respiratory muscle strength, and QoL compared to patients with HCV and HBV.BACKGROUND Liver diseases are responsible for metabolic disorders and loss of muscle mass and function that affect functional status and quality of life (QoL). OBJECTIVE To compare exercise capacity, respiratory muscle strength, and QoL in liver transplant candidates with cirrhosis of the following etiologies: hepatitis C virus (HCV), hepatitis B virus (HBV), and alcoholic cirrhosis (AC). METHODS Cross-sectional study comprising 86 patients divided into three groups: HCV (40 patients), HBV (14 patients), and AC (32 patients). Patients were evaluated using the Six-Minute Walk Test (6MWT), manometry, and the QoL questionnaire SF-36. RESULTS The AC group showed the lowest performance in the 6MWT (meters) compared to the HBV and HCV groups (373.50 ± 50.48, 464.16 ± 32, and 475.94 ± 27.84, respectively, p=0.001). In the domains of the SF-36, the AC group had lower scores for functional capacity and physical limitations when compared to the HBV and HCV groups (p=0.001). In the comparison of respiratory muscle strength, the AC group had lower MIP (cmH2O) compared to the HBV and HCV groups (-65.54 ± 11.28, -71.61 ± 6.96, -82.44 ± 13.71, respectively, p=0.001). The MEP (cmH2O) in the AC group was also lower than in the HBV and HCV groups (65.13 ± 10.74, 82.44 ± 13.87, 83.44 ± 12.20, respectively, p=0.001). CONCLUSION The AC group showed worse exercise capacity, respiratory muscle strength, and QoL compared to patients with HCV and HBV.

Ligadura de ducto biliar como modelo de estudo da síndrome hepatopulmonar e estresse oxidativo

BACKGROUND The hepatopulmonary syndrome is characterized by hepatic dysfunction and presence of dilated pulmonary vessels, with alterations in air diffusion that can be demonstrated in the experimental model of common bile duct ligation. AIM To evaluate the oxidative stress in pulmonary tissue of cirrhotic rats with common bile duct ligation. MATERIAL/METHODS We used 12 male Wistar rats weighing between 200-300 g divided in two groups: control (Co = 6) and cirrhotic (Ci = 6). We evaluated aminotransferases, arterial gasometry, lipoperoxidation and chemoluminescence), and antioxidant enzymatic activity with superoxide dismutase. The tissues analyzed for hepatopulmonary syndrome were cirrhotic liver and lung. RESULTS The animals with common bile duct ligation showed alterations in the following aminotransferases: aspartate aminotransferase, Co = 105.3 +/- 43/Ci = 500.5 +/- 90.3, alanine aminotransferase, Co = 78.75 +/- 37.7/Ci = 162.75 +/- 35.4, and alkaline phosphatase, Co = 160 +/- 20.45/Ci = 373 +/- 45.44. The lipoperoxidation and the antioxidant response had significant differences between the groups when evaluated in lung (lipoperoxidation) Co = 0.87 +/- 0.3/Ci = 2.01 +/- 0.9, chemoluminescence Co = 16008.41 +/- 1171.45/Ci = 20250.36 +/- 827.82 superoxide dismutase Co = 6.66 +/- 1.34/Ci = 16.06 +/- 2.67. CONCLUSIONS Our results suggest that in this experimental model of cirrhosis using common bile duct ligation, there is an increase in lipoperoxidation in pulmonary tissue as well as an increase in superoxide dismutases antioxidant activity, suggesting a pulmonary injury caused by secondary biliary cirrhosis.

Survival benefit of liver transplantation and the effect of underlying liver disease

BACKGROUND The benefit of liver transplantation relative to initial degree of underlying liver disease and time on the waiting list remains poorly defined. We sought to examine the survival benefit attributable to liver transplantation across a wide range of Model for End-Stage Liver Disease (MELD) scores. METHODS The study population included patients with end-stage liver disease enlisted in Rio Grande do Sul, Brazil, between 2001 and 2005. Survival and hazard function for enlisted and transplanted patients were estimated using parametric and nonparametric methods. MELD score was utilized to account for underlying liver disease. RESULTS Of 1,130 eligible patients, 520 (46.0%) were transplanted, 266 (23.5%) died on the waiting list, 141 (12.5%) were excluded from the waiting list, and 203 (18.0%) remained enlisted and were awaiting transplantation at the time of last observation. At 1 year after transplantation, a MELD score of 15 represented a transition point in terms of overall survival benefit (MELD 10, 90% vs 83%; MELD 15, 81% vs 80%; MELD 20, 63% vs 78%; MELD 25, 42% vs 74%; MELD 30, 21% vs71%; enlisted vs transplant patients, respectively). MELD scores at which transplantation seemed to be beneficial relative to the amount of follow-up time was MELD 23, 17, 15, and 12 at 6 months, and 1, 2, and 5 years, respectively, from time of transplantation/enlistment. CONCLUSION Although patients with greater MELD scores enjoy a pronounced and early benefit from transplantation, patients with lesser MELD scores do gain from transplantation, although a greater period of time is needed to realize the survival benefit.

Antioxidant properties of glutamine and its role in VEGF-Akt pathways in portal hypertension gastropathy

AIM To investigate the effects of glutamine on oxidative/nitrosative stress and the vascular endothelial growth factor (VEGF)-Akt-endothelial nitric oxide synthase (eNOS) signaling pathway in an experimental model of portal hypertension induced by partial portal vein ligation (PPVL). METHODS Portal hypertension was induced by PPVL. The PPVL model consists of a partial obstruction of the portal vein, performed using a 20 G blunt needle as a guide, which is gently removed after the procedure. PPVL model was performed for 14 d beginning treatment with glutamine on the seventh day. On the fifteenth day, the mesenteric vein pressure was checked and the stomach was removed to test immunoreactivity and oxidative stress markers. We evaluated the expression and the immunoreactivity of proteins involved in the VEGF-Akt-eNOS pathway by Western blotting and immunohistochemical analysis. Oxidative stress was measured by quantification of the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) as well as the levels of total glutathione (GSH), superoxide dismutase (SOD) activity, nitric oxide (NO) production and nitrotyrosine immunoreactivity. RESULTS All data are presented as the mean ± SE. The production of TBARS and NO was significantly increased in PPVL animals. A reduction of SOD activity was detected in PPVL + G group. In the immunohistochemical analyses of nitrotyrosine, Akt and eNOS, the PPVL group exhibited significant increases, whereas decreases were observed in the PPVL + G group, but no difference in VEGF was detected between these groups. Western blotting analysis detected increased expression of phosphatidylinositol-3-kinase (PI3K), P-Akt and eNOS in the PPVL group compared with the PPVL + G group, which was not observed for the expression of VEGF when comparing these groups. Glutamine administration markedly alleviated oxidative/nitrosative stress, normalized SOD activity, increased levels of total GSH and blocked NO overproduction as well as the formation of peroxynitrite. CONCLUSION Glutamine treatment demonstrated to reduce oxidative damage but does not reduce angiogenesis induced by PH in gastric tissue, demonstrating a beneficial role for the PI3K-Akt-eNOS pathway.

Model for the end‐stage liver disease and death prediction in a cohort of Brazilian patients on the waiting list for liver transplantation

Abstract:  Background/aim:  To examine the performance of the model for end‐stage liver disease (MELD) score to predict mortality three and six months after enlistment of patients with chronic diseases for their first liver transplantation (LT) and to compare the performances of the Child–Turcotte–Pugh (CTP) and the Erasmus Model for End‐stage Resistant‐to‐therapy All etiology Liver Disease (EMERALD) scores with the MELD to predict mortality.