Gene and protein expression of mTOR and LC3 in hepatocellular carcinoma, colorectal liver metastasis and "normal" liver tissues

The physiological role of autophagy in the progression of liver diseases is still debated. To understand the clinical relevance of autophagy in primary e secondary hepatic tumors, we analyzed the expression of mTOR (mammalian target of rapamycin), a key regulator of autophagy; Raptor (regulatory-associated protein of mTOR); ULK1 (Unc-51 like kinase 1) determinant in the autophagy initiation; LC3 (microtubule-associated protein 1A/1B-light chain 3), a specific marker of autophagosomes; and p62, a selective autophagy receptor. Samples from subjects with chronic hepatitis (n.58), cirrhosis (n.12), hepatocellular carcinoma (HCC, n.56), metastases (n.48) from colorectal cancer and hyperplasia or gallbladder stones (n.7), the latter considered as controls, were examined. Gene expression analysis was carried out in n.213 tissues by absolute q-PCR, while protein expression by Western Blot in n.191 lysates, including tumoral, surrounding tumoral and normal tissues. Nonparametric statistical tests were used for comparing expression levels in the above-mentioned groups. Subgroup analysis was performed considering viral infection and chemotherapy treatment. The mTOR transcriptional level was significantly lower in metastases compared to HCC (P = 0.0001). p-mTOR(Ser2448) and LC3II/LC3I protein levels were significantly higher in metastases compared to HCC (P = 0.008 and P<0.0001, respectively). ULK(Ser757) levels were significantly higher in HCC compared to metastases (P = 0.0002) while the HCV- and HBV- related HCC showed the highest p62 levels. Chemotherapy induced a down-regulation of the p-mTOR(Ser2448) in metastases and in non-tumor surrounding tissues in treated patients compared to untreated (P = 0.001 and P = 0.005, respectively). Conclusions: the different expression of proteins considered, owning their interaction and diverse tissue microenvironment, indicate an impairment of the autophagy flux in primary liver tumors that is critical for the promotion of tumorigenesis process and a coexistence of autophagy inhibition and activation mechanisms in secondary liver tumors. Differences in mTOR and LC3 transcripts emerged in tumor-free tissues, therefore particular attention should be considered in selecting the control group.

CD80-CD28 signaling controls the progression of inflammatory colorectal carcinogenesis

In patients with ulcerative colitis (UC) the cumulative risk of colon cancer is lower than the actual rate of dysplasia suggesting an efficient immune surveillance mechanism. Since the co-stimulatory molecule CD80 is overexpressed in dysplastic colonic mucosa of UC patients and T-cell activation entails effective costimulation, we aimed to evaluate the functional implication of CD80 signaling in colonic UC-associated carcinogenesis. In humans, we observed that the percentage of CD80+ and HLA-A+ IEC was increased in the dysplastic colonic mucosa of UC patients. In vitro, IEC activated CD8+ T-cells through a CD80-dependent pathway. Finally, in the AOM/DSS-induced colonic adenocarcinoma model CD80 signaling inhibition significantly increased the frequency and extension of high-grade dysplasia, whereas enhancing CD80 activity with an anti-CTLA4 antibody significantly decreased colonic dysplasia. In conclusion, CD80 signaling between IEC and T-cells represents a key factor controlling the progression from low to high grade dysplasia in inflammatory colonic carcinogenesis.

Autologous chondrocytes as a novel source for neo-chondrogenesis in haemophiliacs

Haemophilic arthropathy is the major cause of disability in patients with haemophilia and, despite prophylaxis with coagulation factor concentrates, some patients still develop articular complications. We evaluate the feasibility of a tissue engineering approach to improve current clinical strategies for cartilage regeneration in haemophiliacs by using autologous chondrocytes (haemophilic chondrocytes; HaeCs). Little is known about articular chondrocytes from haemophilic patients and no characterisation has as yet been performed. An investigation into whether blood exposure alters HaeCs should be interesting from the perspective of autologous implants. The typical morphology and expression of specific target genes and surface markers were therefore assessed by optical microscopy, reverse transcription plus the polymerase chain reaction (PCR), real-time PCR and flow-cytometry. We then considered chondrocyte behaviour on a bio-hybrid scaffold (based on polyvinyl alcohol/Wharton's jelly) as an in vitro model of articular cartilage prosthesis. Articular chondrocytes from non-haemophilic donors were used as controls. HaeC morphology and the resulting immunophenotype CD44(+)/CD49c(+)/CD49e(+)/CD151(+)/CD73(+)/CD49f(-)/CD26(-) resembled those of healthy donors. Moreover, HaeCs were active in the transcription of genes involved in the synthesis of the extracellular matrix proteins of the articular cartilage (ACAN, COL1A, COL2A, COL10A, COL9A, COMP, HAS1, SOX9), although the over-expression of COL1A1, COL10A1, COMP and HAS was observed. In parallel, the composite scaffold showed adequate mechanical and biological properties for cartilage tissue engineering, promoting chondrocyte proliferation. Our preliminary evidence contributes to the characterisation of HaeCs, highlighting the opportunity of using them for autologous cartilage implants in patients with haemophilia.

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.

Autophagy and apoptosis-related genes in chronic liver disease and hepatocellular carcinoma

Background

Dysregulation of autophagy is important in the pathogenesis of many diseases, including cancer. Several aspects of the biological role of autophagy are however still unclear and the relationship between apoptosis and autophagy, particularly in the liver has yet to be thoroughly explored. In this study we evaluated the expression of Beclin 1 (one of the main autophagocytic agents, which bridges autophagy, apoptosis and both differentiation), and both pro- (Bad, Bax) and anti-apoptotic (Bcl-2, Bcl-xL) factors in liver samples from patients with different stages of liver disease.

Methods

The study concerned 93 patients from 49 cases of chronic hepatitis (CH) (30 HCV and 19 HBV-related), 13 of cirrhosis (CIRR) (10 HCV and 3 HBV-related), 21 of hepatocellular carcinoma (both HCC and peritumoral tissues [PHCC]), and 10 controls (CONTR). Real-time PCR and Western blotting were used to measure mRNA and protein expression levels.

Results

Beclin 1 mRNA levels were lower in HCC than in CH (P = 0.010) or CIRR (P = 0.011), and so were the Bcl-xL transcripts (P < 0.0001). Bad mRNA levels were higher in CH and CIRR than in CONTR, while Bax transcripts were increased in all tissues (P = 0.036). PHCC expressed the highest Bcl-2 mRNA levels. HBV-related CH tissues showed significantly higher Bcl-xL and Bad mRNA levels than HCV-related CH (P = 0.003 and P = 0.016, respectively).

Conclusions

High Beclin 1, Bcl-xL and Bad levels in CH and CIRR tissues suggest an interaction between autophagy and apoptosis in the early and intermediate stages of viral hepatitis. In HCC these processes seem to be downregulated, probably enabling the survival and growth of neoplastic hepatocytes.

Mucosal immune environment in colonic carcinogenesis: CD80 expression is associated to oxidative DNA damage and TLR4-NFκB signalling

BACKGROUND

CD80 has been thought to play an active role in immunosurveillance as it has been found to be up-regulated in ulcerative colitis (UC) patients with dysplasia. The aim of the present study was to analyse early events in UC-related and non-inflammatory carcinogenesis with reference to CD80 expression to clarify what stimuli are involved in its up-regulation in these patients.

PATIENTS AND METHODS

Sixty-two patients affected with UC, UC with dysplasia, UC and cancer, colonic adenoma, or colonic cancer and 11 healthy subjects were enroled in our study. Tissue samples were taken from surgical specimens during colonic resection or during colonoscopy. Mucosal mRNA expression of Toll-like receptor-4 (TLR4) and nuclear factor-kappaB (NF-κB) was quantified with Real Time RT-PCR. TLR4, β-catenin and p53 expressions were analysed by immunohistochemistry. Mucosal levels of activated NF-κB were measured with immunometric assays while 8-Hydroxydeoxyguanosine (8-OHdG) levels were quantified by high-performance liquid chromatography with electrochemical detection (HPLC-ED). Non-parametric tests were used for statistical analysis.

RESULTS

8-OHdG mucosal levels were higher in the patients with UC + dysplasia with respect to those in the patients with UC only (p=0.03). CD80 mRNA mucosal levels were directly correlated with 8-OHdG mucosal levels (τ=0.26, p=0.04), TLR4 protein expression (τ=0.45, p<0.01) and NF-κB mRNA expression and activity (τ=0.24, p=0.02; τ=0.34, p=0.02, respectively). CD80 protein expression, instead, was directly correlated with 8-OHdG mucosal levels (τ=0.19, p=0.05) and inversely correlated with TLR4 mRNA expression (τ=-0.25, p=0.03).

CONCLUSION

Oxidative DNA damage peaked in UC-related dysplasia and was found to be directly correlated to CD80 expression. The direct correlation between TLR4 protein expression and CD80 mRNA and the indirect correlation between CD80 protein and TLR4 mRNA expressions give substance to the hypothesis that they play a role in immunosurveillance. No significant correlations between CD80 expression and p53 and β-catenin accumulation during oncogenesis were, instead, observed.

Oxidative DNA damage correlates with cell immortalization and mir-92 expression in hepatocellular carcinoma

BACKGROUND

MicroRNAs expression has been extensively studied in hepatocellular carcinoma but little is known regarding the relationship, if any, with inflammation, production of reactive oxygen species (ROS), host's repair mechanisms and cell immortalization. This study aimed at assessing the extent of oxidative DNA damage (8-hydroxydeoxyguanosine - 8-OHdG) in different phases of the carcinogenetic process, in relation to DNA repair gene polymorphism, telomeric dysfunction and to the expression of several microRNAs, non-coding genes involved in post-transcriptional regulation, cell proliferation, differentiation and death.

METHODS

Tissue samples obtained either at surgery, [neoplastic (HCC) and adjacent non-cancerous cirrhotic tissues (NCCT)] at percutaneous or laparoscopic biopsy (patients with HCV or HBV-related hepatitis or patients undergoing cholecystectomy) were analysed for 8-OHdG (HPLC-ED), OGG1 (a DNA repair gene) polymorphism (PCR-RFLP), telomerase activity, telomere length (T/S, by RT-PCR), Taqman microRNA assay and Bad/Bax mRNA (RT-PCR). Fifty-eight samples from 29 HCC patients (obtained in both neoplastic and peritumoral tissues), 22 from chronic hepatitis (CH) and 10 controls (cholecystectomy patients - CON) were examined.

RESULTS

Eight-OHdG levels were significantly higher in HCC and NCCT than in CH and CON (p=0.001). Telomerase activity was significantly higher in HCC than in the remaining subgroups (p=0.002); conversely T/S was significantly lower in HCC (p=0.05). MiR-199a-b, -195, -122, -92a and -145 were down-regulated in the majority of HCCs while miR-222 was up-regulated. A positive correlation was observed among 8-OHdG levels, disease stage, telomerase activity, OGG1 polymorphisms and ALT/GGT levels. In HCC, miR-92 expression correlated positively with telomerase activity, 8-OHdG levels and Bad/Bax mRNA.

CONCLUSIONS

The above findings confirm the accumulation, in the progression of chronic liver damage to HCC, of a ROS-mediated oxidative DNA damage, and suggest that this correlates with induction of telomerase activity and, as a novel finding, with over-expression of miR-92, a microRNA that plays a role in both the apoptotic process and in cellular proliferation pathways.

Oxidative DNA damage correlates with cell immortalization and mir-92 expression in hepatocellular carcinoma

BACKGROUND

MicroRNAs expression has been extensively studied in hepatocellular carcinoma but little is known regarding the relationship, if any, with inflammation, production of reactive oxygen species (ROS), host's repair mechanisms and cell immortalization. This study aimed at assessing the extent of oxidative DNA damage (8-hydroxydeoxyguanosine - 8-OHdG) in different phases of the carcinogenetic process, in relation to DNA repair gene polymorphism, telomeric dysfunction and to the expression of several microRNAs, non-coding genes involved in post-transcriptional regulation, cell proliferation, differentiation and death.

METHODS

Tissue samples obtained either at surgery, [neoplastic (HCC) and adjacent non-cancerous cirrhotic tissues (NCCT)] at percutaneous or laparoscopic biopsy (patients with HCV or HBV-related hepatitis or patients undergoing cholecystectomy) were analysed for 8-OHdG (HPLC-ED), OGG1 (a DNA repair gene) polymorphism (PCR-RFLP), telomerase activity, telomere length (T/S, by RT-PCR), Taqman microRNA assay and Bad/Bax mRNA (RT-PCR). Fifty-eight samples from 29 HCC patients (obtained in both neoplastic and peritumoral tissues), 22 from chronic hepatitis (CH) and 10 controls (cholecystectomy patients - CON) were examined.

RESULTS

Eight-OHdG levels were significantly higher in HCC and NCCT than in CH and CON (p=0.001). Telomerase activity was significantly higher in HCC than in the remaining subgroups (p=0.002); conversely T/S was significantly lower in HCC (p=0.05). MiR-199a-b, -195, -122, -92a and -145 were down-regulated in the majority of HCCs while miR-222 was up-regulated. A positive correlation was observed among 8-OHdG levels, disease stage, telomerase activity, OGG1 polymorphisms and ALT/GGT levels. In HCC, miR-92 expression correlated positively with telomerase activity, 8-OHdG levels and Bad/Bax mRNA.

CONCLUSIONS

The above findings confirm the accumulation, in the progression of chronic liver damage to HCC, of a ROS-mediated oxidative DNA damage, and suggest that this correlates with induction of telomerase activity and, as a novel finding, with over-expression of miR-92, a microRNA that plays a role in both the apoptotic process and in cellular proliferation pathways.

Active ankle dorsiflexion and the Mingazzini manoeuvre: two clinical bedside tests related to prognosis of postural transferring, standing and walking ability in patients with stroke

BACKGROUND

Lower limb paresis is one of the main determinants of postural transferring, standing and walking disability in patients with stroke. Early prognosis of recovery of lower limb function and of related functional disability is an important issue in neurorehabilitation clinical practice.

AIM

Aim of this study was to assess the relationship between active ankle dorsiflexion and the Mingazzini manoeuvre with the prognosis of lower limb function and of postural transferring, standing and walking ability in patients with stroke.

DESIGN

This was a longitudinal study with prospectively collected data.

SETTING

University hospital.

POPULATION

The study included 53 patients with first unilateral brain ischemic stroke.

METHODS

Patients were evaluated initially (mean 4.02 days) and approximately at six months (mean 178.6 days) after stroke. Initial assessment included active ankle dorsiflexion and the Mingazzini manoeuvre. The assessment after six months included three outcome measures evaluating the rate of improvement of lower limb function and of postural transferring, standing and walking ability (Postural Assessment Scale for Stroke patients, Functional Ambulation Category, Motricity Index leg subtest).

RESULTS

The active ankle dorsiflexion showed to be related with the prognosis of lower limb function and of walking ability, while the Mingazzini manoeuvre was related with the improvement of postural transferring and standing ability.

CONCLUSION

Active ankle dorsiflexion and the Mingazzini manoeuvre are related with the prognosis of lower limb function and of postural transferring, standing and walking ability in patients with stroke.

CLINICAL REHABILITATION IMPACT

These simple bedside tests give a picture of improvement potential of motor activities connected to lower limb function in patients with acute stroke.

Oxidative stress and inducible nitric oxide synthase induction in carcinogenesis

BACKGROUND

Chronic inflammation is linked to an increased risk of cancer. The molecular mechanisms underlying this correlation have been long investigated and it is well known that the inflammatory cells recruited in the inflamed tissues release chemical mediators, in particular reactive oxygen species (ROS). With respect to digestive systems, ROS have been implicated in a number of pathologies, including Helicobacter pylori-related gastritis, Barrett's esophagus, inflammatory disease of the lower gastrointestinal tract, alcoholic liver disease and several other types of toxic and virus-mediated liver injury. ROS levels within cells and tissues are controlled by numerous antioxidant defense mechanisms, but in inflammation, ROS overproduction exceeds defenses and damage intracellular macromolecules, including nucleic acids, with formation of potentially mutagenic and carcinogenic DNA adducts.

AIMS

This paper summarizes our own experience investigating the link between inflammation, ROS production and oxidative DNA damage as well as the impact of the above events on cytokine and growth factor release, oncogene activation, telomere instability and microRNA in H. pylori-related gastritis, Barrett's esophagus and, in particular, hepatitis C virus-related liver disease. The paper also describes, at least in part, the complex scenario involving nitric oxide production and its impact in some gastrointestinal diseases, as well as a number of other molecular and biochemical changes related to ROS production and inflammation.

CONCLUSIONS

The paper falls obviously short of being an exhaustive summary of our understanding, but the data reported are intended as a stimulus to broaden the knowledge on the topic, also in view of the possible therapeutic implications of any advance obtained.

Bax inhibitor-1 down-regulation in the progression of chronic liver diseases

BACKGROUND

Bax inhibitor-1 (BI-1) is an evolutionary conserved endoplasmic reticulum protein that, when overexpressed in mammalian cells, suppresses the apoptosis induced by Bax, a pro-apoptotic member of the Bcl-2 family. The aims of this study were: (1) to clarify the role of intrinsic anti- and pro-apoptotic mediators, evaluating Bax and BI-1 mRNA and protein expressions in liver tissues from patients with different degrees of liver damage; (2) to determine whether HCV and HBV infections modulate said expression.

METHODS

We examined 62 patients: 39 with chronic hepatitis (CH) (31 HCV-related and 8 HBV-related); 7 with cirrhosis (6 HCV-related and 1 HBV-related); 13 with hepatocellular carcinoma (HCC) [7 in viral cirrhosis (6 HCV- and 1 HBV-related), 6 in non-viral cirrhosis]; and 3 controls. Bax and BI-1 mRNAs were quantified by real-time PCR, and BI-1 protein expression by Western blot.

RESULTS

CH tissues expressed significantly higher BI-1 mRNA levels than cirrhotic tissues surrounding HCC (P < 0.0001) or HCC (P < 0.0001). Significantly higher Bax transcripts were observed in HCV-genotype-1-related than in HCV-genotype-3-related CH (P = 0.033). A positive correlation emerged between BI-1 and Bax transcripts in CH tissues, even when HCV-related CH and HCV-genotype-1-related CH were considered alone (P = 0.0007, P = 0.0005 and P = 0.0017, respectively).

CONCLUSIONS

BI-1 expression is down-regulated as liver damage progresses. The high BI-1 mRNAs levels observed in early liver disease may protect virus-infected cells against apoptosis, while their progressive downregulation may facilitate hepatocellular carcinogenesis. HCV genotype seems to have a relevant role in Bax transcript expression.

TGF-beta1 and IGF-1 and anastomotic recurrence of Crohn's disease after ileo-colonic resection

BACKGROUND

After bowel resection, Crohn's disease (CD) recurs frequently in the site of the anastomosis. Alteration of normal healing processes may play a role in this phenomenon. Transforming growth factor beta (TGF-beta) and insulin-like growth factor (IGF-1) are involved in wound healing mechanisms with pro-fibrogenic properties. The aim of this study was to assess the expression of TGF-beta1 and insulin-like growth factor 1 (IGF-1) in the different zones of the bowel wall to understand why side-to-side anastomosis are associated to a lower recurrence rate compared to end-to-end ones.

PATIENTS AND METHODS

Seventeen patients affected by CD who underwent ileo-colonic resection from 2004 to 2005 were enrolled in this study. Full-thickness tissue samples were obtained from the mesenteric, the lateral, and the anti-mesenteric sides of the macroscopically diseased and healthy ileum for each patient. TGF-beta1 and IGF-1 messenger RNAs (mRNAs) were quantified by real-time polymerase chain reaction. Myeloperoxidase activity and histological disease activity were assessed to quantify the ileal inflammation. Vimentin, desmin, and alpha-smooth muscle actin were stained with immunohistochemistry to assess the fibroblast, smooth muscle cell, and myofibroblasts populations. Comparisons and correlations were carried out with nonparametric tests.

RESULTS

In diseased ileum, TGF-beta1 mRNA transcripts in the antimesenteric side were significantly lower than those of the mesenteric side (p = 0.05), and a significant correlation between TGFbeta-1 levels in diseased bowel and the sampling site was observed (tau = 0.36, p = 0.03). On the contrary, neither the IGF-1 mRNA transcripts nor the distribution of fibroblast, smooth muscle cell, and myofibroblasts populations showed any relation with the sampling site.

CONCLUSION

TGF-beta1 mRNA expression was lower in the anti-mesenteric side of the diseased ileum, and this was consistent with the success of side-to-side anastomosis in preventing CD recurrence. Since high expression of TGF-beta1 was associated to early recurrence, it seems rationale to construct the anastomosis on the anti-mesenteric side of the bowel.

Fas / FasL system, IL-1beta expression and apoptosis in chronic HBV and HCV liver disease

The Fas / Fas-ligand (FasL) system is an important death signal pathway in the liver. An enhanced local inflammatory response prompted by FasL expression, which contributes to neutrophil recruitment and interleukin-1 beta (IL-1beta) release, seems to be crucial to chronic liver damage, persistence of viral infections, and probably initiation and / or promotion of HCC. In order to evaluate the expression of Fas, FasL, and IL-1beta in different stages of human liver disease and to determine whether hepatitis B virus (HBV) and hepatitis C virus (HCV) infections modulate their expression, also in relation to apoptosis, we examined 87 liver samples obtained from patients with: chronic hepatitis (CH) (n.42), cirrhosis (n.9) and hepatocellular carcinoma (HCC) (n.16) and corresponding peritumoural tissues (n.16); histologically-normal liver (n.4) as controls. Fas, FasL and IL-1beta mRNA were quantified using reverse transcriptase-polymerase chain reaction. The apoptotic index was evaluated by TUNEL analysis. Our data showed a progressive Fas / FasL increase from CH to cirrhosis followed by a decline from the latter to HCC. In histological sections apoptosis was detected in HCC. A significant difference emerged between HCV and HBV-related disease for IL-1beta expression only in CH. A significant positive correlation between IL-1beta and FasL in HCV-related disease (P = 0.014) and an inverse correlation between IL-1beta and Fas in HBV-related disease (P = 0.021) were observed. The different pattern of IL-1beta, Fas and FasL expression found in HCV- and HBV-mediated liver disease, points to a different modulation of immune response B and C virus induced, while the decline in Fas / FasL expression in HCC may be related to defence mechanisms adopted by HCC cells against the immune system.

Oxidative DNA damage in gastric cancer: CagA status and OGG1 gene polymorphism

Oxidative DNA damage is thought to play an important part in the pathogenesis of H. pylori-induced mucosal damage. 8-OHdG is a sensitive marker of DNA oxidation and is repaired by a polymorphic glycosylase (OGG1) more effectively than by OGG1-Cys(326). The aims of this study were to ascertain the respective roles of H. pylori, cagA status and OGG1 polymorphism in determining 8-OHdG levels in benign and premalignant stomach diseases and in gastric cancer (GC). The study involved 50 GC patients (for whom both neoplastic tissue and surrounding mucosa were available), 35 with intestinal metaplasia and atrophy (IMA) and 43 controls. H. pylori and cagA status were determined by histology and polymerase chain reaction for urease and cagA. 8-OHdG was assayed using HPLC with an electrochemical detector (HPLC-ED). The OGG1 1245C-->G transversion was identified using RFLP analyses. 8-OHdG levels were significantly higher in GC, with no differences in relation to H. pylori or cagA status. OGG1 polymorphism was documented in 34% of GC (15 Ser/Cys, 2 Cys/Cys). OGG1 1245C-->G polymorphism was detected in 54% of IMA patients, but only 16% of controls (p = 0.0004) and coincided with significantly higher 8-OHdG levels. In the multivariate analysis, 8-OHdG levels were predicted by histotype and OGG1 status. OGG1 1245C-->G polymorphism was common in both GC and IMA, but very rare in controls, and correlated more closely with 8-OHdG levels than do H. pylori infection or cagA status.

Hepatitis C virus: from oxygen free radicals to hepatocellular carcinoma

Epidemiological evidence clearly identifies chronic infection with hepatitis C virus (HCV) as a major risk factor for the development of hepatocellular carcinoma (HCC). Among the mechanisms that have been implicated in the pro-carcinogenic effect of HCV infection, an increased production of reactive oxygen species in the liver seems to have a major pathogenetic role in leading from chronic inflammation to cancer. Recent data have also demonstrated that HCV is capable of inducing this active production of free radicals per se, not just through inflammation, a feature peculiar to this virus and the specific activity of its core protein. This paper provides an overview of the inter-relationships between HCV, liver damage, free radical production and HCC, describing at least in part the complex network involving DNA oxidative damage, cytokine synthesis, proto-oncogene activation and oestrogen receptor expression, that may all be deeply involved in liver carcinogenesis.

Oxidative damage, pro-inflammatory cytokines, TGF-α and 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-α and 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 TNF-α, IL-1β, TGF-α and c-myc in liver specimens was detected by semi-quantitative comparative RT-PCR.

RESULTS: TNF-α levels were significantly higher in hepatitis patients than in cirrhosis patients (P = 0.05). IL-1β was higher in cirrhosis patients (P = 0.05). A significant correlation was found between TNF-α and staging (P = 0.05) and between IL-1β levels 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-α expression and HCV genotype (P = 0.02).

CONCLUSION: In chronic HCV-related liver damage, oxidative DNA damage correlates with HCV genotype, grading and TNF-α levels. As HCV-related liver damage progresses, TNF-α levels drop while IL-1β and c-myc levels increase, which may be relevant to liver carcinogenesis.

Efficacy of zinc supplementation in preventing acute hepatitis in Long-Evans Cinnamon rats

OBJECTIVES

Long-Evans Cinnamon (LEC) rats are characterized by an abnormal hepatic deposition of copper (Cu) due to a lack of the Cu-transporter P-type adenosine triphosphatase: accordingly, the strain is a good animal model of Wilson's disease. The effect of oral zinc (Zn) acetate treatment on the development of acute hepatitis and the biochemical parameters of Cu-induced liver damage was studied in 5-week-old LEC rats (n=52).

METHODS

Rats receiving 50 or 80 mg/ml/day Zn acetate by gavage and control rats receiving a daily dose of glucose solution 0.02 g/ml by gastric intubation were killed at 1, 2 or 8 weeks after the start of treatment.

RESULTS

Treatment with Zn acetate resulted in the prevention of acute hepatitis: 10 of the 13 untreated rats developed signs and symptoms compatible with acute hepatitis between the 6th and 7th week of treatment. Tissue metallothionein (MT) significantly increased in the treated rats and positively correlated with Zn concentrations within the liver. Control rats had a significantly higher iron concentration in the liver and kidneys compared with supplemented rats, after both short- and long-term experiments. 8-hydroxy-2'-deoxyguanosine amounts were significantly lower in untreated rats.

CONCLUSIONS

Zn acetate prevents acute hepatitis, by increasing tissue MT concentrations, reducing Cu absorption and interfering with Fe metabolism.

Effects of iron manipulation on trace elements level in a model of colitis in rats

AIM: Trace elements (TE) metabolism is altered in inflammatory bowel diseases. TE (zinc and copper) are constituents of antioxidant enzymes. Iron is involved in the pathogenesis of chronic inflammation. The aim was to evaluate zinc and copper status and the effects of iron manipulation in experimental colitis.

METHODS: Twenty-four male Sprague-Dawley rats were divided into four groups: standard diet, iron-deprived diet, iron-supplemented diet, and sham-treated controls. Macroscopic damage was scored. DNA adducts were measured in the colon. Liver and colonic concentration of TE were measured.

RESULTS: Macroscopic damage was reduced in iron-deprived groups and increased in iron-supplemented rats. Damage to the DNA was reduced in iron-deprived groups and increased in iron-supplemented groups. Liver and colonic iron concentrations were reduced in iron-deprived and increased in iron-supplemented rats. Liver zinc concentration was reduced after supplementation whereas colonic levels were similar in controls and treated rats. Liver copper concentration was reduced in all the colitic groups except in the iron-supplemented group whereas colonic concentration was increased in iron-deprived rats.

CONCLUSION: Iron deprivation diminishes the severity of DNBS colitis while supplementation worsens colitis. Zinc and copper status are modified by iron manipulation.

Transcriptional downregulation of tight junction protein ZO-1 in active coeliac disease is reversed after a gluten-free diet

Coeliac disease is an autoimmune enteropathy characterized by an enhanced permeability of the intestinal epithelial barrier. In epithelial cells paracellular permeability is regulated by intercellular tight junction. The cytoplasmic protein ZO-1 interacts directly with F-actin and plays a pivotal role in the structural and functional organization of tight junction.

AIM

The aim of this study was to investigate the expression and localization of ZO-1 in the intestinal mucosa of coeliac patients.

PATIENTS AND METHODS

Twenty patients with active coeliac disease, seven of whom underwent a repeat biopsy following a gluten-free diet and 27 control subjects, were studied. In all subjects, three biopsies were obtained from distal duodenum during upper gastrointestinal endoscopy. ZO-1 protein localization and levels were detected by immunofluorescence followed by confocal microscopy analysis and immunoblotting. ZO-1 mRNA expression was assessed by RT-PCR. F-actin distribution was also investigated.

RESULTS

In patients with active coeliac disease, both ZO-1 protein levels and mRNA were clearly reduced. Cytoskeletal organization was disrupted with F-actin staining concentrated at the subcortical and basal surface regions. Abnormalities in ZO-1 expression and actin organization were reversed after a gluten-free diet.

CONCLUSIONS

In active coeliac disease, ZO-1 protein expression is downregulated at the transcriptional level in association with F-actin redistribution. These changes are completely reversed after a gluten-free diet and could contribute to the increased intestinal paracellular permeability observed in this disorder.

Cytokine, infiltrating macrophage and T cell-mediated response to development of primary and secondary human liver cancer

BACKGROUND

Kupffer cells, monocytes and infiltrating T cells have been considered the major source of interleukin-1beta and tumour necrosis factor-alpha in the liver. AIMS; To explore the expression of interleukin-1beta and tumour necrosis factor-alpha and to evaluate the density and the distribution of T lymphocytes and monocytes/macrophages in the liver of patients with primary and secondary tumours.

METHODS

Tumoural and peritumoural liver samples were examined from 21 patients with hepatocellular carcinoma, 10 with hepatic metastases, 5 with benign focal liver lesions and 4 healthy adult livers. Interleukin-1beta and tumour necrosis factor-alpha mRNAs were detected by a semiquantitative comparative reverse transcriptase polymerase chain reaction. T lymphocytes and monocytes/macrophages were detected by immunohistochemistry.

RESULTS

Higher levels of interleukin-1beta, tumour necrosis factor-alpha, CD3+ and CD68+ cells were found in the tissue surrounding hepatocellular carcinoma and metastases than in the tumour itself. A strong expression of CD68+ and CD3+ cells was found mainly along the tumour-host interface but the highest expression of CD3+ cells was found at the metastasis interfaces. Interleukin-1beta expression, CD3+ and CD68+ cell densities were higher in peritumoural samples than in so-called "normal" liver tissue.

CONCLUSIONS

An increased production of interleukin-1beta and, to a lesser extent, of tumour necrosis factor-alpha mRNA coincides with the presence of cancer be it primary or secondary, both in healthy and cirrhotic livers. The presence of cancer, irrespective of the presence of underlying liver damage, appears to play the most important role.

Estrogens receptors and oxidative damage in the liver

There is considerable evidence that reactive oxygen species (ROS) have a causative role in chronic hepatic injury and cancer development via direct and indirect mechanisms. Estrogens produce free oxygen radicals through redox cycling and affect cell proliferation, also in the liver. We are presently involved in evaluating the possible relationship between estrogens receptor expression, type of receptor, oxidative DNA damage and c-myc in chronic liver disease. The data on DNA adducts, c-myc mRNA and variant estrogen receptor in patients with HCV- or HBV-related chronic liver disease are suggesting that those positive for variant liver estrogen receptor present higher genomic oxidative damage, as reflected in 8-OHdG levels. We are also observing that patients with chronic hepatitis and cirrhosis, when positive for variant estrogen receptor, present higher c-myc m-RNA expression, a factor reportedly associated with increased genomic instability, augmented cytoproliferation and carcinogenesis. Our own and other author's data are shedding new light on estrogen pathophysiology, liver damage and hepatic cancer.

Relationship between apoptosis, tumour necrosis factor, and cell proliferation in chronic cholestasis

BACKGROUND

Target of the immune response in chronic autoimmune cholestasis, is the bile duct epithelium. Lymphocytic infiltration and apoptosis have both been suggested to mediate the destruction of hepatocytes and biliary epithelium in primary biliary cirrhosis.

AIMS

To further address this issue in two cholestatic liver diseases characterized by an autoimmune pathogenesis and, furthermore, evaluate the relationship between apoptosis and both tumour necrosis factor alpha and cell proliferation.

METHODS

Liver tissue specimens from 16 patients with primary biliary cirrhosis, 15 with primary sclerosing cholangitis, and 16 with chronic hepatitis C (controls) were evaluated. DNA-fragmentation of apoptotic cells was ascertained by the TdT-mediated deoxyuridine triphosphate nick-end labelling method. Tumour necrosis factor alpha expression and cell proliferation (Ki-67 antigen) were assayed by immunohistochemistry.

RESULTS

Hepatocytes with DNA fragmentation were observed in 75% of patients with primary biliary cirrhosis, in 66.6% with primary sclerosing cholangitis, and in 43.7% with chronic hepatitis C. Biliocytes showed apoptosis in only 3 cases of primary biliary cirrhosis. Biliocytes showed a strong cytoplasmic expression in 4 cases (1 primary biliary cirrhosis, 2 primary sclerosing cholangitis and 1 chronic hepatitis C). A few intralobular and portal inflammatory mononuclear cells expressing tumour necrosis factor alpha were observed in 62.5% of patients with primary biliary cirrhosis, 46.1% with primary sclerosing cholangitis, and 56.2% with hepatitis C virus chronic hepatitis. The amount of intraportal mononuclear cells expressing Ki-67 antigen was significantly higher in primary biliary cirrhosis specimens than in primary sclerosing cholangitis (p<0.001) or hepatitis C virus-related chronic hepatitis (p<0.03). No correlation was found within the 3 groups of patients between the Ki-67 histological score and the severity of liver disease. Moreover, no relationship was found between TdT-mediated deoxyuridine triphosphate nick-end labelling and either tumour necrosis factor alpha or Ki-67 staining.

CONCLUSIONS

Apoptosis is a phenomenon which frequently involves hepatocytes in chronic autoimmune cholestasis. This process is apparently parallel, but unrelated to cell proliferation. Cell proliferation mainly involves mononuclear cells in portal tracts of primary biliary cirrhosis specimens. The finding of tumour necrosis factor alpha expression in biliocytes deserves further study to establish whether this cytokine is involved in triggering bile duct lesions.

Rabbit interleukin-1 receptor antagonist. Cloning, expression, functional characterization, and regulation during intestinal inflammation

Genomic and cDNA clones for rabbit interleukin-1 receptor antagonist (IL-1ra) were isolate based on homology with the human, mouse, and rat IL-1ra gene. A partial genomic clone, obtained by screening a rabbit genomic library, contained coding sequences for the carboxyl-terminal 108 amino acids of rabbit IL-1ra. Two classes of cDNA for rabbit IL-1ra were obtained using RNA from inflamed rabbit colon tissue. One class of cDNA coded for a secreted form of IL-1ra, whereas the other coded for a putative intracellular form of rabbit IL-1ra. The latter form is similar to that isolated from human epithelial cells. A partially synthetic rabbit IL-1ra gene was constructed and expressed in Escherichia coli. The recombinant rabbit IL-1ra was purified to homogeneity by ion exchange chromatography. Its affinity was similar to that of human IL-1ra for the human and mouse type I IL-1 receptor. From the cDNA clone and the purified recombinant protein, specific probes were developed for measuring levels of rabbit IL-1ra mRNA and protein in normal and inflamed rabbit tissues. Unlike IL-1 alpha and IL-1 beta, IL-1RA mRNA and protein were present at detectable levels in normal rabbit colon. During the development of an experimental formalin-immune complex colitis, rabbit IL-1 alpha showed a dramatic increase in tissue levels, consistent with previous results; IL-1ra also increased 3-4-fold. Treatment of colitis rabbits with corticosteroids significantly suppressed neutrophil infiltration, corticosteroid treatment suppressed IL-1ra but not IL-1 alpha mRNA steady-state levels. Our observations demonstrate that IL-1 and IL-1ra synthesis is differentially regulated in healthy and inflamed intestinal tissue.

[Specific IgE in the gastric and duodenal mucosa. An epiphenomenon or pathogenetic mechanism of some forms of "peptic" ulcer?]

Allergic mechanisms have been shown to induce gastric and intestinal damage in animal models. It has been demonstrated that people allergic to food may complain of gastrointestinal disorders. Furthermore food allergens can induce gastric mucosal damage in sensitized people. Little is known as regards allergic mechanisms underlying "peptic" ulcers although there are reports suggesting that some forms of gastric and duodenal ulcer may be caused by allergy. AIM. Of the study was to evidence if IgE specific to food and inhalants are localized in gastric and duodenal mucosa and if the in vitro incubation of gastric and duodenal biopsies with specific allergens, stimulate mast-cell mediators. MATERIALS AND METHODS. Twenty-one patients affected by gastric/duodenal ulcers (14 with high total IgE serum levels) and 16 controls were studied. All patients were submitted to upper digestive endoscopy and biopsies were taken from gastric fundus, body and antrum and duodenal bulb. Specific IgE to food and inhalant allergens were tested after homogenization of biopsies, using commercial kits. In 3 selected patients, 3 biopsies from gastric fundus and 3 from duodenal bulb were taken. After incubation of mucosal of mucosal biopsies with allergens (wheat, lactoalbumin, Parietaria J. pollen), the release of histamine and tryptase was measured. The release of Pepsinogen A was measured in the same conditions, as control. RESULTS. Specific IgE to food and inhalants allergens have been found in 164/586 tests (27.9%) of "peptic" ulcer patients and in 17/430 tests (4%) of controls. The duodenal bulb resulted the site in which most frequently IgE have been found. The release of histamine and tryptase has been stimulated only in 1/6 tests by incubation of biopsies with specific allergens in patients with specific IgE. PG-A release has been always stimulated by incubation of gastric biopsies, but not duodenal biopsies, with all tested allergens. DISCUSSION AND CONCLUSION. Specific IgE may be localized in gastric and duodenal mucosa of patients with "peptic" ulcer and/or food allergy. This event is linked to high total IgE serum levels and in a lesser extent, intestinal parasitosis, it is not strictly correlated with specific IgE in the serum and it regards both food and inhalant allergens. No relevant effects were observed after incubation of specific allergens with gastric or duodenal mucosa biopsies containing specific IgE. The possibility that higher allergens concentration stimulate mediator release from mast cells should be investigated. A defect of the gastric or duodenal epithelial barrier which permit a passage way for proteins with subsequent IgE production in the submucosa, appears to be the cause of localization of specific IgE in stomach and duodenum.