Oxidative damage in the progression of chronic liver disease to hepatocellular carcinoma:An intricate pathway

The histo-pathologic and molecular mechanisms leading to initiation and progression of hepatocellular carcinoma(HCC)are still ill-defined;however,there is increasing evidence that the gradual accumulation of mutations,genetic and epigenetic changes which occur in preneoplastic hepatocytes results in the development of dysplastic foci,nodules,and finally,overt HCC.As well as many other neoplasias,liver cancer is considered an"inflammatory cancer",arising from a context of inflammation,and characterized by inflammation-related mechanisms that favor tumor cell survival,proliferation,and invasion.Molecular mechanisms that link inflammation and neoplasia have been widely investigated,and it has been well established that inflammatory cells recruited at these sites with ongoing inflammatory activity release chemokines that enhance the production of reactive oxygen species.The latter,in turn,probably have a major pathogenic role in the continuum starting from hepatitis followed by chronic inflammation,and ultimately leading to cancer.The relationship amongst chronic liver injury,free radical production,and development of HCC is explored in the present review,particularly in the light of the complex network that involves oxidative DNA damage,cytokine synthesis,telomere dysfunction,and microRNA regulation.

5-ASA colonic mucosal concentrations resulting from different pharmaceutical formulations in ulcerative colitis

AIM:To compare the mucosal concentrations of 5-aminosalicylic acid(5-ASA)resulting from different pharmaceutical formulations and analyse the influence of inflammation on the mucosal concentrations.METHODS:The study included 130 inflammatory bowel disease(IBD)patients receiving 5-ASA as pH-dependent-release formulations(73 patients),time-dependent-release formulations(11 patients),or pro-drugs(18patients).In addition,28 patients were receiving topical treatment(2-4 g/d)with pH-dependent-release formulations.Endoscopic biopsies were obtained from the sigmoid region during the colonoscopy.The 5-ASA concentrations(ng/mg)were measured in tissue homogenatesusing high-pressure liquid chromatography with electrochemical detection.The t test and Mann-Whitney test,when appropriate,were used for statistical analysis.RESULTS:Patients receiving pH-dependent-release formulations showed significantly higher mucosal concentrations of 5-ASA(51.75±5.72 ng/mg)compared with patients receiving pro-drugs(33.35±5.78 ng/mg,P=0.01)or time-dependent-release formulations(38.24±5.53 ng/mg,P=0.04).Patients with endoscopic remission had significantly higher mucosal concentrations of5-ASA than patients with active disease(60.14±7.95ng/mg vs 35.66±5.68 ng/mg,P=0.02).Similar results were obtained when we compared patients with the histological appearance of remission and patients with active histological inflammation(67.53±9.22 ng/mg vs 35.53±5.63 ng/mg,P<0.001).Significantly higher mucosal concentrations of 5-ASA were detected in patients treated with both oral and topical treatments in combination compared with patients who received oral treatment with pH-dependent-release formulations alone(72.33±11.23 ng/mg vs 51.75±5.72 ng/mg,P=0.03).CONCLUSION:IBD patients showed significant variability in mucosal 5-ASA concentrations depending on the type of formulation,and the highest mean concentration was achieved using pH-dependent-release formulations.

Oxidative damage,pro-inflammatory cytokines,TGF-αand c-myc in chronic HCV-related hepatitis and cirrhosis

AIM: To assess whether a correlation exists between oxidative DNA damage occurring in chronic HCV-related hepatitis and expression levels of pro-inflammatory cytokines, TGF-αand c-myc. METHODS: The series included 37 patients with chronic active HCV-related hepatitis and 11 with HCV-related compensated cirrhosis. Eight-hydroxydeoxyguanosine in liver biopsies was quantified using an electrochemical detector. The mRNA expression of TIMF-α, IL-1β, TGF-αand c-myc in liver specimens was detected by semi-quantitative comparative RT-PCR. RESULTS: TNF-αlevels were significantly higher in hepatitis patients than in cirrhosis patients (P=0.05). IL-1βwas higher in cirrhosis patients (P=0.05). A significant correlation was found between TNF-αand staging (P=0.05) and between IL-1βlevels and grading (P=0.04). c-myc showed a significantly higher expression in cirrhosis patients (P=0.001). Eight-hydroxydeoxyguanosine levels were significantly higher in cirrhosis patients (P=0.05) and in HCV genotype 1 (P=0.03). Considering all patients, 8-hydroxydeoxyguanosine levels were found to be correlated with genotype (P=0.04) and grading (P=0.007). Also multiple logistic regression analysis demonstrated a significant correlation among the number of DNA adducts, TNF-αexpression and HCV genotype (P=0.02). CONCLUSION: In chronic HCV-related liver damage, oxidative DNA damage correlates with HCV genotype, grading and TNF-αlevels. As HCV-related liver damage progresses, TNF-αlevels drop while IL-1βand c-myc levels increase, which may be relevant to liver carcinogenesis.

Antioxidative potential of a combined therapy of anti TNFα and Zn acetate in experimental colitis

AIM:To evaluate whether combination therapy with antitumour necrosis factor α (TNFα) antibody and Zn acetate is beneficial in dextran sodium sulphate (DSS) colitis.METHODS:Colitis was induced in CD1-Swiss mice with 5% DSS for 7 d.The experimental mice were then randomised into the following subgroups:standard diet + DSS treated (induced colitis group);standard diet + DSS + subcutaneous 25 μg anti-TNFα treated group;Zn acetate treated group + DSS + subcutaneous 25 μg anti-TNFα;standard diet + DSS + subcutaneous 6.25 μg anti-TNFα treated group and Zn acetate treated group + DSS + subcutaneous 6.25 μg anti-TNFα.Each group of mice was matched with a similar group of sham control animals.Macroscopic and histological features were scored blindly.Homogenates of the colonic mucosa were assessed for myeloperoxidase activity as a biochemical marker of inflammation and DNA adducts (8OH-dG) as a measure of oxidative damage.RESULTS:DSS produced submucosal erosions,ulcers,inflammatory cell infiltration and cryptic abscesses which were reduced in both groups of mice receiving either anti-TNFα alone or combined with zinc.The effect was more pronounced in the latter group (vs Zn diet,P < 0.02).Myeloperoxidase activity (vs controls,P < 0.02) and DNA adducts,greatly elevated in the DSS fed colitis group (vs controls,P < 0.05),were significantly reduced in the treated groups,with a more remarkable effect in the group receiving combined therapy (vs standard diet,P < 0.04).CONCLUSION:DSS induces colonic inflammation which is modulated by the administration of anti-TNFα.Combining anti-TNFα with Zn acetate offers marginal benefit in colitis severity.