Protective effects of coffee-derived compounds on lipopolysaccharide/D-galactosamine induced acute liver injury in rats

Associations of Coffee Consumption with the Circulating Level of Alanine Aminotransferase and Aspartate Aminotransferase. A Meta-Analysis of Observational Studies

Background: The associations of coffee consumption with the circulating level of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) remains controversial. We conducted a meta-analysis of observational studies to sum up the existing evidence about this matter.Methods: A comprehensive literature-search up to January 2020, using PubMed, Embase and Web of Science databases, was conducted to identify the relevant observational studies that examined the associations of coffee consumption with the circulating level of ALT and AST. The standard mean difference (SMD) for the level of ALT and AST, odds ratio (OR) for the elevated ALT and AST and their corresponding 95% CIs for the highest versus lowest categories of coffee intake were determined.Results: A total of 19 observational studies, which involved 222,067 individuals, were included in this meta-analysis. The combined SMD suggested that coffee consumption was associated with a lower level of ALT (SMD = -0.14, 95% CI: -0.22 to -0.06; p = 0.001) and AST (SMD = -0.17, 95% CI: -0.20 to -0.13; p < 0.001), respectively. Meanwhile, the overall multivariable adjusted OR showed that coffee consumption was inversely associated with the elevated ALT (OR = 0.69, 95% CI: 0.60 to 0.79; p < 0.001) and AST (OR = 0.62, 95% CI: 0.48 to 0.81; p < 0.001), respectively.Conclusion: The results of this meta-analysis suggest that coffee consumption is inversely associated with the circulating level of ALT and AST, and elevated ALT and AST. More randomized controlled trials are needed to elaborate the concerned issues.

The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: a comprehensive review of the literature

Chlorogenic acid (CGA), an important biologically active dietary polyphenol, is produced by certain plant species and is a major component of coffee. Reduction in the risk of a variety of diseases following CGA consumption has been mentioned in recent basic and clinical research studies. This systematic review discusses in vivo animal and human studies of the physiological and biochemical effects of chlorogenic acids (CGAs) on biomarkers of chronic disease. We searched PubMed, Embase, Amed and Scopus using the following search terms: ("chlorogenic acid" OR "green coffee bean extract") AND (human OR animal) (last performed on April 1st, 2015) for relevant literature on the in vivo effects of CGAs in animal and human models, including clinical trials on cardiovascular, metabolic, cancerogenic, neurological and other functions. After exclusion of editorials and letters, uncontrolled observations, duplicate and not relevant publications the remaining 94 studies have been reviewed. The biological properties of CGA in addition to its antioxidant and anti-inflammatory effects have recently been reported. It is postulated that CGA is able to exert pivotal roles on glucose and lipid metabolism regulation and on the related disorders, e.g. diabetes, cardiovascular disease (CVD), obesity, cancer, and hepatic steatosis. The wide range of potential health benefits of CGA, including its anti-diabetic, anti-carcinogenic, anti-inflammatory and anti-obesity impacts, may provide a non-pharmacological and non-invasive approach for treatment or prevention of some chronic diseases. In this study, the effects of CGAs on different aspects of health by reviewing the related literatures have been discussed.

Nrf2 and Snail-1 in the prevention of experimental liver fibrosis by caffeine

AIM: To determine the molecular mechanisms involved in experimental hepatic fibrosis prevention by caffeine (CFA).

METHODS: Liver fibrosis was induced in Wistar rats by intraperitoneal thioacetamide or bile duct ligation and they were concomitantly treated with CFA (15 mg/kg per day). Fibrosis and inflammatory cell infiltrate were evaluated and classified by Knodell index. Inflammatory infiltrate was quantified by immunohistochemistry (anti-CD11b). Gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction for collagen I (Col-1), connective tissue growth factor (CTGF), transforming growth factor β1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, superoxide dismutase (SOD) and catalase (CAT). Activation of Nrf2 and Snail-1 was analyzed by Western-blot. TNF-α expression was proved by enzyme-linked immunosorbant assay, CAT activity was performed by zymography.

RESULTS: CFA treatment diminished fibrosis index in treated animals. The Knodell index showed both lower fibrosis and necroinflammation. Expression of profibrogenic genes CTGF, Col-1 and TGF-β1 and proinflammatory genes TNF-α, IL-6 and IL-1 was substantially diminished with CFA treatment with less CD11b positive areas. Significantly lower values of transcriptional factor Snail-1 were detected in CFA treated rats compared with cirrhotic rats without treatment; in contrast Nrf2 was increased in the presence of CFA. Expression of SOD and CAT was greater in animals treated with CFA showing a strong correlation between mRNA expression and enzyme activity.

CONCLUSION: Our results suggest that CFA inhibits the transcriptional factor Snail-1, down-regulating profibrogenic genes, and activates Nrf2 inducing antioxidant enzymes system, preventing inflammation and fibrosis.

Effects of globin digest and its active ingredient Trp-Thr-Gln-Arg on galactosamine/lipopolysaccharide-induced liver injury in ICR mice

AIMS

We investigated the effects of globin digest (GD) and its active ingredient Trp-Thr-Gln-Arg (WTQR) on galactosamine/lipopolysaccharide (GalN/LPS)-induced liver injury in imprinting control region (ICR) mice.

MAIN METHODS

The effects of WTQR and GD on the liver injury were examined by measuring the survival rate, serum aminotransferase activities, hepatic components, antioxidant enzyme activities, histopathological analysis, serum levels and hepatic gene expression of tumor necrosis factor-alpha (TNF-α), macrophage inflammatory protein-2 (MIP-2), and nitric oxide (NO) or inducible nitric oxide synthase (iNOS), and nuclear factor-kappa B (NF-κB) p65 content in GalN/LPS-treated ICR mice. RAW264 mouse macrophages were used to confirm the anti-inflammatory effects of WTQR and GD on the macrophages.

KEY FINDINGS

WTQR and GD increased the survival rate, suppressed the serum aminotransferase activities, serum levels and hepatic gene expression of TNF-α, MIP-2, and NO or iNOS, and nuclear NF-κB p65 content in GalN/LPS-treated mice; decreased the oxidized glutathione content, increased the superoxide dismutase activity, and decreased the histopathological grade values of the hepatocyte necrosis and lobular inflammation in GalN/LPS-injured liver; and suppressed the release levels and gene expression of TNF-α, MIP-2, and NO or iNOS, and nuclear NF-κB p65 content in LPS-stimulated RAW264 macrophages. WTQR and GD may improve the antioxidant defense system and inflammatory status in GalN/LPS-injured liver.

SIGNIFICANCE

These findings indicate that WTQR and GD have hepatoprotective effects on GalN/LPS-induced liver injury in ICR mice.

Role of TLR4 and MAPK in the local effect of LPS on intestinal contractility

OBJECTIVES

Lipopolysaccharide (LPS) has been shown to alter intestinal contractility. Toll-like receptor 4 (TLR4), K(+) channels and mitogen-activated protein kinases (MAPKs) have been proposed to be involved in the mechanism of action of LPS. The aim of this study was to determine the role of TLR4, K(+) channels and MAPKs (p38, JNK and MEK1/2) in the local effect of LPS on the acetylcholine (ACh)-induced contractions in rabbit small intestine in vitro.

METHODS

Segments of rabbit duodenum were suspended in the direction of longitudinal or circular smooth muscle fibres in a thermostatically controlled organ bath.

KEY FINDINGS

LPS (0.3 µg/ml) reduced the contractions induced by ACh (100 µm) in the longitudinal and circular smooth muscle of the duodenum after 90 min of incubation. Polymyxin (TLR4 inhibitor), SB203580 (p38 MAPK inhibitor), SP600125 (JNK1/2 inhibitor) and U0126 (MEK1/2 inhibitor) antagonized the effects of the LPS on ACh-induced contractions in duodenal smooth muscle. Incubation with the blockers of K(+) channels, TEA, apamin, charybdotoxin, iberiotoxin, glibenclamide or quinine, did not reverse the effect of LPS on ACh-induced contractions.

CONCLUSIONS

These results suggest that the effect of LPS on ACh-induced contractions in the rabbit duodenum might be mediated by TLR4 and p38, JNK1/2 and MEK1/2 MAPKs.

Methylxanthines, inflammation, and cancer: fundamental mechanisms

Methylxanthines are an integral part of everyday food and drink consumption even though the majority of humans do not identify them by their chemical name. The breakthrough in understanding the action(s) of methylxanthines was in large part due to the understanding that methylxanthines can function as antagonists of adenosine receptors. This represented an example of scientific search and was instructive in view of both new therapeutic options and alarming realizations. It was the subsequent demonstration of the in vivo critical role of A2A adenosine receptors in controlling excessive collateral inflammatory damage that attracted the attention of immunologists to the A2A-adenosine-receptor-antagonizing methylxanthines. We summarize here data showing that caffeine is capable of preventing the inhibition of antitumor T cells in a hypoxic tumor microenvironment. On the other hand, caffeine may exacerbate liver damage by weakening the tissue-protecting A2A adenosine receptor signaling during episodes of acute liver inflammation. However, methylxanthines may also prevent the excessive hepatic connective tissue deposition that is associated with the progression of chronic hepatitis to cirrhosis, which is one of the common causes of mortality.

Coffee consumption could affect the activity of some liver enzymes and other biochemical parameters in healthy drinkers

OBJECTIVE

To investigate the effect of coffee consumption on some liver function indices in adult male and female Nigerians.

SUBJECTS AND METHODS

Thirty apparently healthy subjects, consisting of 18 men and 12 women, were made to consume 2 g of coffee daily for a total of 30 days. Activities of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and plasma concentrations of total and conjugated bilirubin, total protein and albumin were determined using standard methods.

RESULTS

Relative to baseline values, coffee consumption raised mean levels of ALT by 4 IU/l (p < 0.001), AST by 2.0 1 U/l (p < 0.001), ALP by 3.0 1 U/l (p < 0.01), total bilirubin by 0.90 mg/dl (p < 0.05) and total protein by 1.1 g/l (p < 0.05). Gender differences were observed. Significantly higher mean ALP concentration was only seen in male subjects, while mean bilirubin concentration was significantly raised in female volunteers alone. On the other hand, the mean total protein and albumin concentrations in individual male and female groups were not significantly altered (p > 0.05 in each case).

CONCLUSION

The result obtained from the study suggests that short-term consumption of coffee might have a significant effect on the integrity of the liver function tests studied.

Progress in developing rat models of hepatic encephalopathy

Hepatic encephalopathy is a serious complication of acute and chronic liver diseases and has a high mortality rate. The pathogenesis of hepatic encephalopathy remains unclear, and there is no means of prevention or effective cure for the disease. Therefore, there is an urgent need for the basic and clinical research of hepatic encephalopathy to elucidate its pathogenesis. The development of animal models is important for elucidating the pathogenesis of hepatic encephalopathy and providing new avenues for diagnosis and therapy of the disease. Among a variety of animal models, rat model is applied most widely for similarity to humans, repeatability, reliability, applicability, controllability, simplicity and economy. In this paper, we briefly review various rat models of hepatic encephalopathy that have different origins.

Caffeine protects against alcoholic liver injury by attenuating inflammatory response and oxidative stress

OBJECTIVE AND DESIGN

The present investigation was designed to determine the effects of caffeine on alcohol-induced hepatic injury in mice.

MATERIAL

Five groups of mice (8 each) were used.

TREATMENT

The mice treated with different doses of caffeine (5, 10, and 20 mg/kg, respectively).

METHODS

The degree of alcoholic liver injury was evaluated biochemically by measuring serum markers and pathological examination. Real time PCR and ELISA methods were used to check the expression of cytokines and CYP 450.

RESULTS

Treatment with caffeine significantly attenuated the elevated serum aminotransferase enzymes and reduced the severe extent of hepatic cell damage, steatosis and the immigration of inflammatory cells. Interestingly, caffeine decreased hepatic mRNA expression of lipogenic genes, while it had no effect on protein expression of hepatic CYP2E1. Furthermore, caffeine decreased serum and tissue inflammatory cytokines levels, tissue lipid peroxidation and inhibited the necrosis of hepatocytes. Kupffer cells isolated from ethanol-fed mice produced high amounts of reactive oxygen species (ROS) and tumor necrosis factor alpha (TNF-alpha), whereas Kupffer cells from caffeine treatment mice produced less ROS and TNF-alpha.

CONCLUSIONS

These findings suggest that caffeine may represent a novel, protective strategy against alcoholic liver injury by attenuating oxidative stress and inflammatory response.