Could antioxidants be the “magic pill” for cirrhosis-related complications? A pathophysiological appraisal

Protective Effects of Spermidine Against Cirrhotic Cardiomyopathy in Bile Duct-Ligated Rats

Cirrhotic cardiomyopathy is a critical factor that causes morbidity and mortality in crucial conditions such as liver transplantation. In animal model, the common pathophysiologic mechanisms of cirrhotic cardiomyopathy are similar to those associated with bile duct ligation (BDL). Overproduction of inflammatory and oxidant markers plays a crucial role in cirrhotic cardiomyopathy. Spermidine, a multifunctional polyamine, is known for its antioxidant and anti-inflammatory effects. In this study, we investigated the effects of spermidine on development of cirrhotic cardiomyopathy in BDL rats. Rats were randomly housed in 6 groups. Except the normal and sham groups, BDL was performed for all the control and spermidine groups. Seven days after operation, 3 different doses of spermidine (5, 10 and 50 mg/kg) were administrated until day 28, in spermidine groups. At the end of the fourth week, the electrocardiography (ECG) and papillary muscle isolation were performed. The serum level of tumor necrosis factor-a (TNF-α), interleukin-1β (IL-1β), and IL-10 and cardiac level of superoxide dismutase, glutathione (GSH). and malondialdehyde (MDA) were assessed. Furthermore, the nuclear factor-κB (NF-κB) expression was assessed by western blot. Cardiac histopathological changes were monitored. The serum levels of magnesium (Mg) and potassium (K) were investigated. Control group, exhibited exaggerated signs of cirrhotic cardiomyopathy in comparison with the sham group. Co-administration of spermidine at the dose of 10 mg/kg in BDL rats significantly improved the cardiac condition, reduced the inflammatory mediators, and increased antioxidant enzymes. In addition, the histopathologic findings were in accordance with the other results of the study. Besides, there was no significant alteration in serum levels of Mg and K. This study demonstrates that spermidine at the dose of 10 mg/kg significantly improved the cirrhotic cardiomyopathy in BDL model in rats.

Effect of gaseous hydrogen sulphide on growth performance and cecal microbial diversity of weaning pigs

The purpose of this study was to examine the effect of gaseous hydrogen sulphide on growth performance and cecal microbial diversity in weaning pigs. A total of 24 weaning pigs (Landrace × Yorkshire × Duroc; average body weight = 8.55 ± 0.68 kg；weaning at 28 days) were selected and randomly divided into four groups (six replicates in each group). The piglets were exposed to hydrogen sulphide (0, 5, 10 and 15 mg/m³) during the experiment period, which lasted 28 days in four controlled environmental chambers. The results showed that exposure to hydrogen sulphide reduced the average daily gain (ADG), average daily feed intake (ADFI), and increased the diarrhoea rate of piglets. Hydrogen sulphide could increase the abundance and diversity of intestinal microbiota. The abundance of Firmicutes and Proteobacteria increased and Bacteroides decreased in the treatment groups. Five biomarkers, such as Eubacterium_1coprostanoligenes, Clostridiales, Phascolarctobacterium, Acidaminococcaceae and Ruminococcaceae_UCG_002 were selected by Lefse analysis. Our results reveal that hydrogen sulphide damaged the growth performance and destroyed the microbial bacteria balance of weaning pigs. The concentrations of hydrogen sulphide should fall below 5 mg/m³.

Relation between redox homeostasis blood parameters in cirrhotic patients and endothelial dysfunction development

BACKGROUND

Liver is one of the first organs to be exposed to reactive oxygen species (ROS). But the data about the levels of redox homeostasis parameters in the patients with liver cirrhosis (LC) are contradictory. We hypothesized that the levels of malondialdehyde and catalase should change in accordance with the LC severity causing the endothelial dysfunction.

METHODS

In a randomized way with the preliminary stratification by the presence of LC 81 patients and 20 healthy volunteers were examined. To determine the contents of catalase, malondialdehyde, cyclic guanosine monophosphate, endothelin-1, renin, aldosterone, natriuretic peptide, the routine standardized methods were used.

RESULTS

Patients with LC revealed the statistically significant increase of malondialdehyde and decrease of catalase levels in parallel with the increase of cyclic guanosine monophosphate, endothelin-1, renin, aldosterone, natriuretic peptide contents and disease course worsening according to the Child-Pugh criteria. It testifies the huge oxidative stress impact on the organism. Initially, at the stage of LC compensation, it slightly stimulates the activation of antioxidant system, followed by its gradual suppression at the stages of sub- and decompensation. Disorders of redox homeostasis lead to the endothelial dysfunction that becomes the background of extrahepatic comorbid disorders.

CONCLUSIONS

Cirrhotic patients have significant abnormalities in the redox homeostasis, which become the background of the endothelial dysfunction - common trigger mechanism for the syntrophic comorbid diseases and early pathophysiologic symptom of the unfavorable prognosis for such patients.

Research Note: Evaluation of a heat stress model to induce gastrointestinal leakage in broiler chickens

The purpose of this study was to evaluate heat stress as a model to induce gastrointestinal leakage in broiler chickens. On the day of hatch, 320 chicks were allocated into 8 environmental chambers, 4 thermoneutral (TN) and 4 continuous heat stress (HS). Each chamber was divided into 2 pens containing separate feeders and water jugs (8 replicates per treatment, 20 birds/pen). The environment was established to simulate production setting as best possible for the first 21 D. A gradual reduction of temperature from 32°C to 24°C with relative humidity at 55 ± 5% was adopted for the first 21 D. At the time of HS, the HS groups were exposed to 35°C from Day 21 to 42, while thermoneutral ones were maintained at 24°C from Day 21 to 42. Chickens were equipped with a Thermochron temperature logger for continuous monitoring of core body temperature. The environmental temperature and relative humidity were continuously recorded. Fluorescein isothiocyanate–dextran (FITC-d) was orally gavaged to 2 chickens/replicate (n = 16) randomly selected on days 21, 28, 35, and 42. After 1 h of oral gavage, blood samples were collected to determine the passage of FITC-d. Tibias were removed from all chickens to evaluate break strength only on 21 D and 42 D (before HS and at the end of the trial). Performance parameters were evaluated weekly from 21 D to the end of the trial. Body temperature was significantly (P < 0.05) increased after 2 h of starting HS and remained that way until the end of the study. Chronic HS caused an increase in core body temperature which decreased feed intake, body weight, and feed efficiency (28, 35, and 42 D) when compared with control TN chickens. Similarly, serum FITC-d was significantly increased in HS chickens at all points of evaluation. Chronic HS also caused a significant reduction of bone strength at 42 D when compared with the control chickens. The results from the present study suggest that HS can be a robust model to induce gut leakage in broiler chickens.

Propranolol reduces systemic oxidative stress and endotoxemia in cirrhotic patients with esophageal varices

BACKGROUND

The aim of the study was to investigate the effect of propranolol on systemic oxidative stress and endotoxemia in patients with liver cirrhosis and clinically significant portal hypertension evidenced by the presence of esophageal varices.

METHODS

Fourteen patients with liver cirrhosis and esophageal varices, not previously been treated with non-selective beta-blockers (NSBB), were prospectively started on propranolol and followed up for three months. Serum early and late lipid peroxidation products (lipid hydroperoxides [LOOH] and malondialdehyde [MDA], respectively), and endotoxin concentrations in peripheral blood were measured. Fourteen age- and sex-matched healthy individuals were used as controls.

RESULTS

Patients with liver cirrhosis presented significantly higher systemic oxidative stress and endotoxin concentrations compared to healthy controls (P<0.001). Propranolol treatment for one month significantly reduced serum MDA (P<0.05), LOOH (P<0.01), and endotoxin levels (P<0.01) compared to pre-treatment values, whilst LOOH reached control levels. At three months of propranolol treatment, serum LOOH did not differ significantly from the one-month values, whilst serum endotoxin and MDA levels were further reduced between 3- and 1-month period (P<0.05 and P<0.01, respectively), with the latter reaching control levels. Amelioration of systemic endotoxemia at the one- and three-month follow-up intervals (compared to pre-treatment values) was not correlated with the respective reductions in serum MDA and LOOH.

CONCLUSIONS

This is the first study to show that NSBB treatment in liver cirrhosis exerts a significant systemic antioxidant action. This effect seems to be, at least partly, independent of their beneficial effects on intestinal barrier function and endotoxemia.

Protective Effects of the Third Generation Vasodilatory Βeta - Blocker Nebivolol against D-Galactosamine - Induced Hepatorenal Syndrome in Rats

BACKGROUND:

Renal dysfunction is very common in patients with advanced liver cirrhosis and portal hypertension. The development of renal failure in the absence of clinical, anatomical or pathological causes renal of failure is termed hepatorenal syndrome (HRS).

AIM:

The present study was constructed to investigate the possible protective effects of nebivolol (Nebi) against D-galactosamine (Gal)-induced HRS in rats.

MATERIAL AND METHODS:

Rats were treated with Nebi for ten successive days. On the 8th day of the experiment, they received a single dose of Gal. Serum levels of Cr, BUN, Na+ and K+ as well as AST, ALT, total bilirubin (TB), NH3 and endothelin-1 (ET-1) were determined following Gal administration. Moreover, renal and liver contents of MDA, GSH, F2-isoprostanes (F2-IPs), tumor necrosis factor-alpha (TNF-α), nuclear factor kappa-B (NF-κB), total nitric oxide (NO), in addition to activities of caspase-3 (Cas-3), heme oxygenase-1 (HO-1), inducible and endothelial NO synthase (iNOS and eNOS) enzymes were also assessed. Finally, histopathological examination was performed.

RESULTS:

Nebi attenuated Gal-induced renal and hepatic dysfunction. It also decreased the Gal-induced oxidative stress and inflammatory recruitment.

CONCLUSION:

Results demonstrated both nephroprotective and hepatoprotective effects of Nebi against HRS and suggested a role of its antioxidant, anti-inflammatory, anti-apoptotic and NO-releasing properties.

Optimizing Fluorescein Isothiocyanate Dextran Measurement As a Biomarker in a 24-h Feed Restriction Model to Induce Gut Permeability in Broiler Chickens

Fluorescein isothiocyanate dextran (FITC-d) is a 3–5 kDa marker used to measure tight junction permeability. We have previously shown that intestinal barrier function can be adversely affected by stress, poorly digested diets, or feed restriction (FR), resulting in increased intestinal inflammation-associated permeability. However, further optimization adjustments of the current FITC-d methodology are possible to enhance precision and efficacy of results in future. The objective of the present study was to optimize our current model to obtain a larger difference between control and treated groups, by optimizing the FITC-d measurement as a biomarker in a 24-h FR model to induce gut permeability in broiler chickens. One in vitro and four in vivo independent experiments were conducted. The results of the present study suggest that by increasing the dose of FITC-d (8.32 versus 4.16 mg/kg); shortening the collection time of blood samples (1 versus 2.5 h); using a pool of non-FITC-d serum as a blank, compared to previously used PBS; adding a standard curve to set a limit of detection and modifying the software’s optimal sensitivity value, it was possible to obtain more consistent and reliable results.

Is intestinal oxidative stress involved in patients with compensated liver cirrhosis?

BACKGROUND

Liver cirrhosis is associated with intestinal epithelial barrier dysfunction, which may be affected by oxidative stress. Studies in cirrhotic rats provided evidence for intestinal oxidative stress, but studies in cirrhotic patients are scarce. We have shown intestinal barrier dysfunction in patients with compensated cirrhosis.

AIM

The present study aimed to investigate whether oxidative stress occurs in the intestinal mucosa of compensated cirrhotic patients and may contribute to barrier dysfunction.

MATERIAL AND METHODS

Oxidative stress was studied in duodenal and sigmoid biopsies from 15 cirrhotic patients and 22 controls by analyzing transcription of genes involved in glutathione and uric acid metabolism using quantitative real-time polymerase chain reaction. Protein levels of glutathione and glutathione disulphide were measured and the glutathione/glutathione disulphide ratio was calculated as marker of oxidative stress. In addition, intestinal myeloperoxidase and fecal calprotectin were determined.

RESULTS

Gene transcription of glutathione synthetase and glutathione reductase were significantly different in duodenal and sigmoid biopsies of cirrhotic patients vs. controls, but no alterations were found for other genes nor for glutathione, glutathione disulphide, glutathione/glutathione disulphide ratio and intestinal myeloperoxidase and fecal calprotectin concentrations.

CONCLUSION

This study did not find indications for oxidative stress and low-grade inflammation in the small and large intestine of stable compensated cirrhotic patients. Although these preliminary findings need further validation, we found intestinal oxidative stress not to be a major mechanism contributing to epithelial barrier dysfunction in patients with compensated cirrhosis.

Cirrhosis induces apoptosis in renal tissue through intracellular oxidative stress

BACKGROUND

Renal failure is a frequent and serious complication in patients with decompensated cirrhosis.

OBJECTIVES

We aimed to evaluate the renal oxidative stress, cell damage and impaired cell function in animal model of cirrhosis.

METHODS

Secondary biliary cirrhosis was induced in rats by ligation of the common bile duct. We measured TBARS, ROS and mitochondrial membrane potential in kidney as markers of oxidative stress, and activities of the antioxidant enzymes. Relative cell viability was determined by trypan blue dye-exclusion assay. Annexin V-PE was used with a vital dye, 7-AAD, to distinguish apoptotic from necrotic cells and comet assay was used for determined DNA integrity in single cells.

RESULTS

In bile duct ligation animals there was significant increase in the kidney lipoperoxidation and an increase of the level of intracellular ROS. There was too an increase in the activity of all antioxidant enzymes evaluated in the kidney. The percentage viability was above 90% in the control group and in bile duct ligation was 64.66% and the dominant cell death type was apoptosis. DNA damage was observed in the bile duct ligation. There was a decreased in the mitochondrial membrane potential from 71.40% ± 6.35% to 34.48% ± 11.40% in bile duct ligation.

CONCLUSIONS

These results indicate that intracellular increase of ROS cause damage in the DNA and apoptosis getting worse the renal function in cirrhosis.

Baicalein reduces the occurrence of cirrhotic endotoxemia by reducing intestinal mucosal apoptosis

BACKGROUND

The dried roots of Scutellaria baicalensis Georgi, is known in traditional Chinese medicine as Huang Qin (H. qin), and it has been officially and traditionally used in treatment of various diseases such as hepatitis in China. Baicalein (BA), a flavonoid originally isolated from H. qin, has shown a wide range of biological activities. This study was to evaluate whether baicalein, can reduce the intestinal mucosal cell apoptosis caused by cirrhotic endotoxemia and its possible mechanisms.

METHODS

For this purpose, compound factors modeling was used to establish endotoxemic cirrhotic rat model. Firstly, we evaluated endotoxin, ALT, AST and TBIL levels after the baicalein treatment (20 mg/kg, i.v.). To investigate the mechanism of baicalein effect on apoptosis, TUNEL assay was used to detect intestinal mucosal apoptosis. RT-PCR was used to detect the expression levels of gene Bcl-2 mRNA and Bax mRNA in intestinal mucosal tissues. Caspase-3 activity of intestinal tissue was detected with colorimetric method in our experiments.

RESULTS

After treatment with BA, the serum endotoxin concentration, the intestinal mucosal apoptosis rate and the activity of caspase-3 of the baicalein group were significantly lower than that of the model and the glutamine group. The serum ALT, AST and TBIL concentration of the BA group were significantly lower than that of the model group. The body weight of the baicalein group was significantly lower than that of the normal group, but it was higher than that of the model group. Among the treatment groups, the mRNA level of anti-apoptotic gene Bcl-2 was the lowest in the model group and the highest in the baicalein group while the mRNA level of pro-apoptotic gene Bax was the lowest in the baicalein group and the highest in the model group.

CONCLUSION

The present results demonstrated that baicalein could reduce the occurrence of cirrhotic endotoxemia partly by reducing intestinal mucosal apoptosis.

Dexmedetomidine attenuates oxidative stress induced lung alveolar epithelial cell apoptosis in vitro

Background. Oxidative stress plays a pivotal role in the lung injuries of critical ill patients. This study investigates the protection conferred by α₂ adrenoceptor agonist dexmedetomidine (Dex) from lung alveolar epithelial cell injury induced by hydrogen peroxide (H₂O₂) and the underlying mechanisms. Methods. The lung alveolar epithelial cell line, A549, was cultured and then treated with 500 μM H₂O₂ with or without Dex (1 nM) or Dex in combination with atipamezole (10 nM), an antagonist of α₂ receptors. Their effect on mitochondrial membrane potential (Δψ_m), reactive oxygen species (ROS), and the cell cycle was assessed by flow cytometry. Cleaved-caspases 3 and 9, BAX, Bcl-2, phospho-mTOR (p-mTOR), ERK1/2, and E-cadherin expression were also determined with immunocytochemistry. Results. Upregulation of cleaved-caspases 3 and 9 and BAX and downregulation of Bcl-2, p-mTOR, and E-cadherin were found following H₂O₂ treatment, and all of these were reversed by Dex. Dex also prevented the ROS generation, cytochrome C release, and cell cycle arrest induced by H₂O₂. The effects of Dex were partially reversed by atipamezole. Conclusion. Our study demonstrated that Dex protected lung alveolar epithelial cells from apoptotic injury, cell cycle arrest, and loss of cell adhesion induced by H₂O₂ through enhancing the cell survival and proliferation.

Intestinal epithelial barrier function in liver cirrhosis: an extensive review of the literature

Recent evidence suggests that translocation of bacteria and bacterial products, such as endotoxin from the intestinal lumen into the systemic circulation is a contributing factor in the pathogenesis of chronic liver diseases and the development of complications in cirrhosis. In addition to alterations in the intestinal microbiota and immune system, dysfunction of the intestinal epithelial barrier may be an important factor facilitating bacterial translocation. This review aims to provide an overview of the current evidence of intestinal epithelial barrier dysfunction in human chronic liver diseases and cirrhosis, and to discuss possible contributing factors and mechanisms. Data suggest the presence of intestinal epithelial barrier dysfunction in patients with chronic liver diseases, but are more convincing in patients with cirrhosis, especially in those with complications. The barrier dysfunction can result from both direct and indirect effects of aetiological factors, such as alcohol and obesity, which can cause chronic liver diseases and ultimately cirrhosis. On the other hand characteristics of cirrhosis itself, including portal hypertension, alterations in the intestinal microbiota, inflammation and oxidative stress can affect barrier function of both small and large intestine and may contribute to the development of complications. In conclusion, there are indications for intestinal epithelial barrier dysfunction in patients with chronic liver diseases and especially in patients with cirrhosis, which can be caused by various factors affecting both the small and large intestine.

Preoperative use of romiplostim in thrombocytopenic patients with chronic hepatitis C and liver cirrhosis

BACKGROUND AND AIM

Patients infected with hepatitis C virus (HCV) often develop chronic liver disease, liver cirrhosis and concurrent thrombocytopenia, which manifests as decreased platelet counts and bleeding complications. Romiplostim, a thrombopoietin mimetic peptibody that stimulates the thrombopoietin receptor, has been used as a treatment for primary immune thrombocytopenia. We monitored the efficacy of preoperative romiplostim over 90 days in 35 male patients with chronic hepatitis C, liver cirrhosis and thrombocytopenia secondary to HCV infection.

METHODS

Romiplostim was administered at 2 μg/kg Q1W for a maximum of one month with a target platelet count of 70 × 10(9)/L as a prerequisite for planned surgeries. Bone marrow aspirate was collected at baseline and at the end of the study, along with liver and kidney function assessments. A complete blood count was performed every third day throughout the study period.

RESULTS

A rapid response to romiplostim therapy was observed, with 33/35 patients achieving platelet counts ≥ 70 × 10(9)/L and thereby eligible for surgery. An initial mean platelet count of 31 × 10(9)/L increased to a maximum peak range of 73-240 × 10(9)/L, occurring between days 18 and 39. The reticulin bone marrow grade remained negative in all patients. Surgical interventions were associated with no postoperative bleeding or thrombotic complications.

CONCLUSIONS

Preoperative romiplostim administration may represent a viable alternative to increase platelet counts to a level acceptable for elective surgical interventions in patients with chronic liver disease and severe thrombocytopenia secondary to HCV infection who are unresponsive to standard therapy. Further studies in larger numbers of patients and over a longer period of time are warranted.