Emanuele Albano

Amedeo Avogadro University of Eastern Piedmont, Novara, Piedmont, Italy

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Publications (221)1143.91 Total impact

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    ABSTRACT: To test the significance of lipid peroxidation in the development of alcoholic liver injury, an ethanol (EtOH) liquid diet was fed to male 129/SvJ mice (WT) and glutathione S-transferase A4-4 null (GSTA4-/-) mice for 40 d. GSTA4-/- mice were crossed with peroxisome proliferator-activated receptor-α null mice (PPARα-/-) and effects of EtOH in the resulting dKO mice were compared to the other strains. EtOH increased lipid peroxidation in all except WT mice (P< 0.05). Increased steatosis, mRNA expression of inflammatory markers: CXCL2 and tumor necrosis factor α (TNF) and of smooth muscle actin (αSMA) were observed in EtOH GSTA4-/- compared to EtOH WT mice (P<0.05). EtOH PPARα-/- mice had increased steatosis, serum alanine aminotransferase (ALT) and hepatic CD3+ T-cell populations, and elevated mRNA encoding CD14, CXCL2, TNFα, IL-6, CD138, transforming growth factor β(TGFβ), platelet derived growth factor receptor β (PDGFR), matrix metalloproteinase (MMP) 9 and 13, αSMA and collagen type 1 compared to EtOH WT mice. EtOH-fed dKO mice displayed elevation of periportal hepatic 4-HNE adducts and serum antibodies against malondialdehyde-adducts compared to EtOH-feeding of GSTA4-/-, PPARα-/- and WT mice (P<0.05). ALT was higher in EtOH dKO mice compared to all other groups (P<0.001). EtOH-fed dKO mice displayed elevated mRNAs for TNF and CD14, histological evidence of fibrosis, and increased PDGFR, MMP 9 and 13 mRNAs, compared to the EtOH GSTA4-/- or EtOH PPARα-/- genotype (P<0.05). These findings demonstrate the central role lipid peroxidation plays in mediating progression of alcohol-induced necroinflammatory liver injury, stellate cell activation, matrix remodeling and fibrosis. Copyright © 2014, American Journal of Physiology- Gastrointestinal and Liver Physiology.
    AJP Gastrointestinal and Liver Physiology 12/2014; · 3.74 Impact Factor
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    ABSTRACT: Autoimmune reactions involving cytochrome P4502E1 (CYP2E1) are a feature of idiosyncratic liver injury induced by halogenated hydrocarbons and isoniazid, but are also detectable in about one third of the patients with advanced alcoholic liver disease (ALD) and chronic hepatitis C (CHC). In these latter the presence of anti-CYP2E1 auto-antibodies is an independent predictor of extensive necro-inflammation and fibrosis and worsens the recurrence of hepatitis following liver transplantation, indicating that CYP2E1-directed autoimmunity can contribute to hepatic injury. The molecular characterization of the antigens recognized by anti-CYP2E1 auto-antibodies in ALD and CHC has shown that the targeted conformational epitopes are located in close proximity on the molecular surface. Furthermore, these epitopes can be recognized on CYP2E1 expressed on hepatocyte plasma membranes where they can trigger antibody-mediated cytotoxicity. This does not exclude that T cell-mediated responses against CYP2E1 might also be involved in causing hepatocyte damage. CYP2E1 structural modifications by reactive metabolites and molecular mimicry represent important factors in the breaking of self-tolerance against CYP2E1 in, respectively, ALD and CHC. However, genetic or acquired interferences with the mechanisms controlling the homeostasis of the immune system are also likely to contribute. More studies are needed to better characterize the impact of anti-CYP2E1 autoimmunity in liver diseases particularly in relation to the fact that common metabolic alterations such as obesity and diabetes stimulates hepatic CYP2E1 expression. Copyright © 2014. Published by Elsevier B.V.
    Redox biology. 11/2014; 3C:72-78.
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    ABSTRACT: Annexin A1 (AnxA1) is an effector of the resolution of inflammation highly effective in terminating acute inflammatory responses. However, its role in chronic settings is less investigated. Since changes in AnxA1 expression within the adipose tissue characterize obesity in mice and humans, we queried a possible role for AnxA1 in the pathogenesis of nonalcoholic steatohepatitis (NASH), a disease commonly associated with obesity. NASH was induced in wild-type (WT) and AnxA1 knockout (AnxA1-KO) C57BL/6 mice by feeding a methionine-choline deficient (MCD) diet up to 8 weeks. In MCD-fed WT mice, hepatic AnxA1 increased in parallel with the progression of liver injury. This mediator was also detected in liver biopsies from patients with NASH and its degree of expression inversely correlated with the extent of fibrosis. In both humans and rodents, AnxA1 production was selectively localized in liver macrophages. NASH in AnxA1-KO mice was characterized by enhanced lobular inflammation due to increased macrophage recruitment and the exacerbation of the M1 phenotype. Consistently, in vitro addition of recombinant AnxA1 to macrophages isolated from NASH livers down-modulated M1 polarization through stimulation of IL-10 production. Furthermore, the degree of hepatic fibrosis was enhanced in MCD-fed AnxA1-KO mice, an effect associated with augmented liver production of the pro-fibrotic lectin galectin-3. Accordingly, AnxA1 addition to isolated hepatic macrophages reduced galectin-3 expression. Conclusions: Macrophage-derived AnxA1 plays a functional role in modulating hepatic inflammation and fibrogenesis during NASH progression, suggesting the possible use of AnxA1 analogues for the therapeutic control of this disease. (Hepatology 2014;).
    Hepatology 03/2014; · 11.19 Impact Factor
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    ABSTRACT: Previous studies have shown that human nonalcoholic steatohepatitis (NASH) is often associated with the presence of circulating antibodies against protein adducted by lipid peroxidation products. Here we used the methionine-choline deficient (MCD) model of NASH to characterize the possible involvement of adaptive immunity in NASH. In mice fed up to 8 weeks with the MCD diet the extension of liver injury and lobular inflammation paralleled the development of immunoglobulin G (IgG) against malonyldialdehyde (MDA) and 4-hydroxynonenal (4-HNE)-derived antigens as well as with the hepatic recruitment of CD4(+) and CD8(+) T-lymphocytes responsive to the same antigens. Moreover, in these animals the individual IgG reactivity against MDA-adducts positively correlated with transaminase release and hepatic tumor necrosis factor alpha (TNF-α) expression. To substantiate the role of immune responses triggered by oxidative stress in the progression of NASH, mice were immunized with MDA-adducted bovine serum albumin (MDA-BSA) before feeding the MCD diet. MDA-BSA immunization did not affect control mice livers, but further stimulated transaminase release, lobular inflammation, and the hepatic expression of proinflammatory cytokine in MCD-fed mice. The increased severity of NASH in immunized MCD-fed mice involved liver recruitment and the T helper (Th)-1 activation of CD4(+) T cells that, in turn, further stimulated macrophage M1 responses. Moreover, hepatic fibrosis was also evident in these animals in relation with an IL-15-mediated increase of natural killer T-cells (NKT) and the up-regulation in liver production of osteopontin by NKT cells and hepatic macrophages. Conclusion: These results indicate that oxidative stress can contribute to the progression of NASH by stimulating both humoral and cellular immune responses, pointing to the possible role of adaptive immunity in the pathogenesis of the disease. (Hepatology 2013).
    Hepatology 10/2013; 59(3). · 11.19 Impact Factor
  • Journal of Hepatology 04/2013; 58:S511. · 10.40 Impact Factor
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    ABSTRACT: Growing evidence indicates that NF-kB activation contributes to the pathogenesis of non-alcoholic steatohepatisis (NASH). Among the NF-kB sub-units, p50/NFkB1 has regulatory activities down-modulating NF-kB-mediated responses. In this study we investigated the effects of NFKB1 deficiency on the progression of NASH induced by feeding mice with a methionine-choline deficient (MCD) diet. Following 4 weeks on the MCD diet, steatosis, ALT release, hepatocyte apoptosis, lobular inflammation and TNF-α production were higher in NFKB1-ko than in wild-type (WT) mice. NFkB1-/- mice also showed appreciable centrilobular collagen deposition, increased number of activated hepatic stellate cells and higher type-I procollagen-α and TIMP-1 mRNA expression. Despite NF-kBp50 homodimers regulate macrophage activation, the number of hepatic macrophages and liver mRNAs for inducible NO synthase, IL-12p40, CCL2, CXCL10 were comparable in the two strains. NASH was associated with an increase in liver infiltrating T-lymphocytes that was more evident in MCD-fed NFKB1-/- than in similarly treated WT mice. Flow-cytorimetry showed that T cell recruitment involved effector CD8+-T cells without changes in the helper CD4+ T-cell fraction. Furthermore, while NASH lowered hepatic natural killer T cells (NKT) in WT mice, the NKT pool was selectively increased in the livers of MCD-fed NFkB1-/- mice. Such a NKT recruitment was associated with an early over-expression of IL-15, a cytokine controlling NKT cell survival and maturation. In the livers of MCD-fed NFkB1-/- mice, but not in those of WT littermates, we also observed an up-regulation in the production of NKT-related cytokines IFN-γ and osteopontin. Altogether these results indicated that NF-KB1 down-modulation enhanced NASH progression to fibrosis by favoring NKT cell recruitment, stressing the contribution of NKT cells in the pathogenesis of NASH.
    Clinical Science 09/2012; · 5.63 Impact Factor
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    ABSTRACT: Expression of CCL2 (CC chemokine ligand 2) (or monocyte chemoattractant protein-1) regulates inflammatory cell infiltration in the liver and adipose tissue, favouring steatosis. However, its role in the pathogenesis of steatohepatitis is still uncertain. In the present study, we investigated the development of non-alcoholic steatohepatitis induced by an MCD diet (methionine/choline-deficient diet) in mice lacking the CCL2 gene on two different genetic backgrounds, namely Balb/C and C57/Bl6J. WT (wild-type) and CCL2-KO (knockout) mice were fed on a lipid-enriched MCD diet or a control diet for 8 weeks. In Balb/C mice fed on the MCD diet, a lack of CCL2 was associated with lower ALT (alanine transaminase) levels and reduced infiltration of inflammatory cells, together with a lower generation of oxidative-stress-related products. Sirius Red staining demonstrated pericellular fibrosis in zone 3, and image analysis showed a significantly lower matrix accumulation in CCL2-KO mice. This was associated with reduced hepatic expression of TGF-β (transforming growth factor-β), type I procollagen, TIMP-1 (tissue inhibitor of metalloproteinases-1) and α-smooth muscle actin. In contrast, in mice on a C57Bl/6 background, neither ALT levels nor inflammation or fibrosis were significantly different comparing WT and CCL2-KO animals fed on an MCD diet. In agreement, genes related to fibrogenesis were expressed to comparable levels in the two groups of animals. Comparison of the expression of several genes involved in inflammation and repair demonstrated that IL (interleukin)-4 and the M2 marker MGL-1 (macrophage galactose-type C-type lectin 1) were differentially expressed in Balb/C and C57Bl/6 mice. No significant differences in the degree of steatosis were observed in all groups of mice fed on the MCD diet. We conclude that, in experimental murine steatohepatitis, the effects of CCL2 deficiency are markedly dependent on the genetic background.
    Clinical Science 04/2012; 123(7):459-71. · 5.63 Impact Factor
  • Journal of Hepatology 04/2012; 44:S9. · 10.40 Impact Factor
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    ABSTRACT: NEFA (non-esterified 'free' fatty acid)-mediated lipotoxicity plays a critical role in the pathogenesis of NASH (non-alcoholic steatohepatitis). In the light of the growing need for new therapeutic options for NASH, we investigated the action of A2aR (adenosine A(2a) receptor) stimulation against lipotoxicity. The effects of the A(2a)R agonist CGS21680 [2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxyamidoadenosine] were evaluated 'in vitro' in liver cells exposed to SA (stearic acid) and 'in vivo' in rats with NASH induced by 8 weeks of feeding with an MCD diet (methionine/choline-deficient diet). In cultured hepatocytes, SA promoted apoptosis by inducing MKK4 (mitogen-activated protein kinase kinase 4)/SEK1 (stress-activated protein kinase/extracellular-signal-regulated kinase kinase-1) and JNK-1/2 (c-Jun N-terminal kinase-1/2) activation. CGS21680 addition prevented JNK-1/2 activation and reduced apoptosis without interfering with lipid accumulation. CGS21680 action required PI3K (phosphoinositide 3-kinase)/Akt-mediated block of MKK4/SEK1. Consistently, PI3K inhibition with wortmannin abolished the cytoprotective action of CGS21680 and reverted MKK4 inhibition. SA lipotoxicity was also prevented by transfecting HTC cells with a specific MKK4/SEK1 siRNA (small interfering RNA). In rats receiving the MCD diet, the development of NASH was associated with MKK4/SEK1 and JNK-1/2 activation. CGS21680 (0.5 mg/kg of body weight, intraperitoneal) administration to MCD-fed rats prevented JNK-1/2 activation by acting on MKK4/SEK1. CGS21680 also effectively reduced NASH-associated ALT (alanine aminotransferase) release, hepatocyte apoptosis, liver inflammation and fibrosis without affecting hepatic steatosis. Taken together, these results demonstrate that, by inhibiting JNK-1/2, A(2a)R stimulation reduces lipotoxicity and ameliorates NASH, giving a rationale to investigate A(2a)R agonists as possible new therapeutic agents in preventing fatty liver progression to NASH.
    Clinical Science 03/2012; 123(5):323-32. · 5.63 Impact Factor
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    Emanuele Albano
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    ABSTRACT: Stimulation of innate immunity is increasingly recognized to play an important role in the pathogenesis of alcoholic liver disease (ALD), while the contribution of adaptive immunity has received less attention. Clinical and experimental data show the involvement of Th-1 and Th-17 T-lymphocytes in alcoholic hepatitis. Nonetheless, the mechanisms by which alcohol triggers adaptive immunity are still incompletely characterized. Patients with advanced ALD have circulating IgG and T-lymphocytes recognizing epitopes derived from protein modification by hydroxyethyl free radicals and end products of lipid-peroxidation. High titers of IgG against lipid peroxidation-derived antigens are associated with an increased hepatic production of proinflammatory cytokines/chemokines. Moreover, the same antigens favor the breaking of self-tolerance towards liver constituents. In particular, autoantibodies against cytochrome P4502E1 (CYP2E1) are evident in a subset of ALD patients. Altogether these results suggest that allo- and autoimmune reactions triggered by oxidative stress might contribute to hepatic inflammation during the progression of ALD.
    International journal of hepatology. 01/2012; 2012:893026.
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    ABSTRACT: In humans, there is large inter-individual variability in the evolution of NAFLD (non-alcoholic fatty liver disease) to NASH (non-alcoholic steatohepatitis). To investigate this issue, NASH was induced with an MCD (methionine-choline-deficient) diet in C57BL/6 and Balb/c mice that are characterized by different biases in Th1/Th2 and macrophage (M1/M2) responses. Following 4 weeks on the MCD diet, steatosis and lobular inflammation were prevalent in C57BL/6 (Th1, M1 oriented) than in Balb/c (Th2, M2 oriented) mice. Consistently, hepatic TNFα (tumour necrosis factor α) mRNA expression and circulating TNFα levels were higher in MCD-fed C57BL/6 than in MCD-fed Balb/c mice. The Th1/Th2 bias did not account for the increased NASH severity, as in both strains MCD feeding did not significantly modify the liver mRNA expression of the Th1 markers IFNγ (interferon γ) and T-bet or that of the Th2 markers IL-4 (interleukin 4) and GATA-3. Conversely, MCD-fed C57BL/6 mice displayed higher liver mRNAs for the macrophage M1 activation markers iNOS (inducible NO synthase), IL-12p40 and CXCL10 (CXC chemokine ligand 10) than similarly treated Balb/c mice, without effects on the M2 polarization markers IL-10 and MGL-1 (macrophage galactose-type C-type lectin-1). Circulating IL-12 was also higher in MCD-fed C57BL/6 than in MCD-fed Balb/c mice. The analysis of macrophages isolated from the livers of MCD-fed animals confirmed an enhanced expression of M1 markers in C57BL/6 mice. Among all of the MCD-treated mice, liver iNOS, IL-12p40 and CXCL10 mRNA levels positively correlated with the frequency of hepatic necro-inflammatory foci. We concluded that the macrophage M1 bias in C57BL/6 mice may account for the increased severity of NASH in this strain, suggesting macrophage responses as important contributors to NAFLD progression.
    Clinical Science 12/2011; 122(11):545-53. · 5.63 Impact Factor
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    ABSTRACT: The aim of this study was to assess the actual effectiveness of long-term phlebotomy by comparing histological improvement (HI) in 69 Caucasian HCV-RNA-positive CHC patients undergoing phlebotomy or receiving an interferon-based therapy without virological response [nonresponders to interferon therapy(IBT-NR)]. HI was defined by at least one point reduction of the staging score or, in the case of unchanged stage, by at least two points reduction of the grading score (Knodel's Activity Index) and was retrospectively evaluated by comparing two consecutive (56 ± 28 months apart) liver biopsies from 30 phlebotomized and 39 IBT-NR patients. HI was observed in 15 of 30 (50%) patients treated with phlebotomy and in six of 39 (15%) IBT-NR subjects (P=0.002). Furthermore, AST, ALT, and GGT serum levels were significantly reduced only in phlebotomized patients (P ≤ 0.003) at the time of the second biopsy. Univariate and multivariate analysis showed that histological grading score before therapy (P=0.001) and phlebotomy (P=0.002) were independently predictors of HI. HI induced by long-term phlebotomy effectively exceeds that spontaneously occurring in patients IBT-NR confirming the efficacy of iron depletion in attenuating CHC progression when other therapies have failed.
    European journal of gastroenterology & hepatology 11/2011; 23(12):1178-84. · 1.66 Impact Factor
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    ABSTRACT: Postconditioning is a procedure based on the induction of intracellular protective reactions immediately after the onset of reperfusion. Because of the growing need to prevent ischemia/reperfusion (I/R) injury during liver surgery and transplantation, we investigated the possibility of pharmacologically inducing hepatic postconditioning. The effects of the adenosine A2A receptor agonist 2p-(2-carboxyethyl)-phenyl-amino-5'-N-ethylcarboxyamido-adenosine (CGS21680; 5 μmol/L) and the phosphatase and tensin homologue deleted from chromosome 10 (PTEN) inhibitor dipotassium bisperoxo-(5-hydroxypyridine-2-carboxyl)-oxovanadate [bpV(HOpic); 250 nmol/L] were investigated in primary rat hepatocytes during reoxygenation after 24 hours of cold storage and in an in vivo model of rat liver warm I/R. The addition of CGS21680 at reoxygenation significantly reduced hepatocyte death through the activation of the phosphoinositide 3-kinase (PI3K)-protein kinase B (PKB)/Akt signal pathway and through the reduction of the intracellular level of PTEN. PTEN lowering was associated with the increased generation of reactive oxygen species after A2A receptor-mediated stimulation of β-nicotinamide adenine dinucleotide phosphate oxidase (NOX). The inhibition of PI3K or NOX with wortmannin or diphenyleneiodonium chloride, respectively, and the addition of the antioxidant N,N'-diphenyl-p-phenylenediamine reversed the effects of CGS21680. The PTEN inhibitor bpV(HOpic) mimicked the protection provided by CGS21680 against reoxygenation damage. An in vivo rat treatment with CGS21680 or bpV(HOpic) during reperfusion after 1 hour of partial hepatic ischemia also promoted PKB/Akt activation and ameliorated alanine aminotransferase release and histological lesions induced by 2 hours of reperfusion. We conclude that adenosine A2A receptor agonists and PTEN inhibitors are possibly useful agents for the pharmacological induction of postconditioning in the liver.
    Liver Transplantation 04/2011; 17(4):474-82. · 3.79 Impact Factor
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    ABSTRACT: Ischemia/reperfusion (I/R) injury still represents an important cause of morbidity following hepatic surgery and limits the use of marginal livers in hepatic transplantation. Transient blood flow interruption followed by reperfusion protects tissues against damage induced by subsequent I/R. This process known as ischemic preconditioning (IP) depends upon intrinsic cytoprotective systems whose activation can inhibit the progression of irreversible tissue damage. Compared to other organs, liver IP has additional features as it reduces inflammation and promotes hepatic regeneration. Our present understanding of the molecular mechanisms involved in liver IP is still largely incomplete. Experimental studies have shown that the protective effects of liver IP are triggered by the release of adenosine and nitric oxide and the subsequent activation of signal networks involving protein kinases such as phosphatidylinositol 3-kinase, protein kinase C δ/ε and p38 MAP kinase, and transcription factors such as signal transducer and activator of transcription 3, nuclear factor-κB and hypoxia-inducible factor 1. This article offers an overview of the molecular events underlying the preconditioning effects in the liver and points to the possibility of developing pharmacological approaches aimed at activating the intrinsic protective systems in patients undergoing liver surgery.
    World Journal of Gastroenterology 12/2010; 16(48):6058-67. · 2.43 Impact Factor
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    ABSTRACT: Male Sprague-Dawley rats were chronically fed a high-unsaturated-fat diet for 130 days by using total enteral nutrition (TEN), or the same diet in which ethanol (EtOH) isocalorically replaced carbohydrate calories. Additional groups were supplemented with the antioxidant N-acetylcysteine (NAC) at 1.7 g·kg(-1)·day(-1). Relative to an ad libitum chow-fed group, the high-fat-fed controls had three- to fourfold greater expression of fatty acid transporter CD36 mRNA and developed mild steatosis but little other hepatic pathology. NAC treatment resulted in increased somatic growth relative to controls (4.0 ± 0.1 vs. 3.1 ± 0.1 g/day) and increased hepatic steatosis score (3.5 ± 0.6 vs. 2.7 ± 1.2), associated with suppression of the triglyceride hydrolyzing protein adiponutrin, but produced no elevation in serum alanine aminotransferase (ALT). Chronic EtOH treatment increased expression of fatty acid transport protein FATP-2 mRNA twofold, resulting in marked hepatic steatosis, oxidative stress, and a twofold elevation in serum ALT. However, no changes in tumor necrosis factor-α or transforming growth factor-β expression were observed. Fibrosis, as measured by Masson's trichrome and picrosirius red staining, and a twofold increase in expression of type I and type III collagen mRNA, was only observed after EtOH treatment. Long-term EtOH treatment increased hepatocyte proliferation but did not modify the hepatic mRNAs for hedgehog pathway ligands or target genes or genes regulating epithelial-to-mesenchymal transition. Although the effects of NAC on EtOH-induced fibrosis could not be fully evaluated, NAC had additive effects on hepatocyte proliferation and prevented EtOH-induced oxidative stress and necrosis, despite a failure to reverse hepatic steatosis.
    AJP Gastrointestinal and Liver Physiology 11/2010; 300(1):G109-19. · 3.65 Impact Factor
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    ABSTRACT: We have investigated the presence and the possible clinical implications of oxidative stress in children with non-alcoholic fatty liver disease (NAFLD). The present study was an observational study of oxidative stress parameters in the progression of paediatric NAFLD. We observed the role of oxidative stress in children diagnosed with NAFLD by evaluating: serum protein carbonyls, hepatic expression of 8-hydroxy-2-deoxyguanosine (8-OHG), and circulating antibody against malondialdehyde adducted human serum albumin (MDA-HSA). Forty consecutive children with biopsy-proven NAFLD (27 male; 13 female) referred to Bambino Gesù Children's Hospital, Rome, Italy, from January 2007 to April 2008 were included in the study. Serum variations of protein carbonyls, 8-OHG, and circulating antibody against MDA-HSA were evaluated. Elevated protein carbonyls were evident in 33 subjects (83%) irrespective of obesity and insulin resistance. Moreover, liver biopsies of NAFLD patients positive for circulating protein carbonyls also showed a significant increase in the nuclear staining for 8-OHG (p=0.006; 95% CI 3.1-17.7). Anti-MDA-HSA IgG above control threshold was detected in 25 (63%) children. Although protein carbonyl levels were unrelated with disease severity, patients with elevated anti-MDA-HSA IgG had scores for lobular inflammation significantly higher (p=0.019) than subjects with antibodies within the control range, while steatosis, hepatocyte ballooning and fibrosis were similar. High anti-MDA-HSA reactivity was also associated with a 13-fold increased risk (OR=12.9; 95= CI 1.5-113.8; p=0.013) of a NAFLD activity score (NAS) >or=5. These results demonstrate that oxidative stress has an high prevalence in children with NAFLD and is associated with an increased severity of steatohepatitis.
    International Journal of Molecular Medicine 10/2010; 26(4):471-6. · 1.88 Impact Factor
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    ABSTRACT: Circulating auto-antibodies against cytochrome P4502E1 (CYP2E1) have been observed in a significant fraction of patients with chronic hepatitis C (CHC). This study investigated the clinical significance of these auto-antibodies in relation to their antigen specificity. The presence of anti-CYP2E1 IgG was investigated in 137 consecutive patients with biopsy-proven CHC. Anti-CYP2E1 IgG above control threshold levels was detected in 52 (38%) subjects. By combined immunoprecipitation and western blotting, we observed that among anti-CYP2E1 IgG-positive sera, 23 (44%) were unreactive towards denaturated CYP2E1, indicating a prevalent recognition of conformational CYP2E1 antigens. Conformational anti-CYP2E1 auto-antibodies were unrelated to circulating gamma-globulins, alcohol intake or infection by specific HCV genotypes. The presence of anti-CYP2E1 auto-antibodies was associated with an 11-fold (OR 10.9 95%CI 1.4-86.6 P = 0.008) increased prevalence of necro-inflammatory grading ≥ 4 (Ishack's criteria) and 4-fold (OR 4.0; 95%CI 1.3-11-7: P = 0.014) increased prevalence of fibrosis staging ≥ 2, respectively. Multivariate analysis confirmed conformational anti-CYP2E1 IgG (P = 0.005) and age (P = 0.033) as independent predictors of necro-inflammatory grading ≥ 4. The development of anti-CYP2E1 auto-antibodies targeting conformational CYP2E1 epitopes is associated with more severe liver damage in CHC.
    Journal of Viral Hepatitis 10/2010; 17(10):685-90. · 3.08 Impact Factor
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    ABSTRACT: Circulating auto-antibodies targeting conformational antigens on cytochrome P4502E1 (CYP2E1) are detectable in patients with chronic hepatitis C (CHC) and are associated with more severe necro-inflammation. This study investigated the antigen specificity and the possible origin of these auto-antibodies. CYP2E1 site-directed mutagenesis and molecular simulation were used to characterize the epitope specificity of CHC-associated anti-CYP2E1 auto-antibodies. Immunoprecipitation experiments using differently mutated human CYP2E1s revealed that conformational anti-CYP2E1 antibodies targeted two epitopes located on the molecule surface in an area between Lys(324)-Glu(346) at J-K'' helices overlapping. Such epitopes were not recognized by the sera targeting linear CYP2E1 antigens. The CYP2E1(324-346) peptide showed good homology with two sequences (NS5b(438-449) and NS5b(456-465)) within the NS5b protein of hepatitis C virus (HCV). Consistently, conformational anti-CYP2E1 IgG bind to GST-conjugated NS5b(438-449) and NS5b(456-465) more efficiently than those recognizing CYP2E1 linear antigens. Competition experiments confirmed the cross-reactivity of conformational anti-CYP2E1 IgG with both NS5b(438-449) and NS5b(456-465). Moreover, mice immunized with GST-conjugated NS5b(438-449) or NS5b(456-465) peptides developed antibodies recognizing human CYP2E1. In CHC patients cross-reactivity between CYP2E1 and specific sequences in HCV-NS5b protein can promote the development of auto-antibodies targeting conformational epitopes on the CYP2E1 surface that might contribute to hepatic injury.
    Journal of Hepatology 09/2010; 53(3):431-8. · 9.86 Impact Factor
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    ABSTRACT: In liver ischemic preconditioning (IP), stimulation of adenosine A2a receptors (A2aR) prevents ischemia/reperfusion injury by promoting diacylglycerol-mediated activation of protein kinase C (PKC). By concerting diacylglycerol to phosphatidic acid, diacylglycerol kinases (DGKs) act as terminator of diacylglycerol signalling. This study investigates the role of DGK in the development of hepatocyte IP. DGK activity and cell viability were evaluated in isolated rat hepatocytes preconditioned by 10 min hypoxia followed by 10 min re-oxygenation or by the treatment with the A2aR agonist, CGS21680, and subsequently exposed to prolonged hypoxia. We observed that after IP or A2aR activation, a decrease in DGK activity was associated with the onset of hepatocyte tolerance to hypoxia. CGS21680-induced stimulation of A2aR specifically inhibited DGK isoform theta by activating RhoA-GTPase. Consistently, both siRNA-mediated downregulation of DGK theta and hepatocyte pretreatment with the DGK inhibitor R59949 induced cell tolerance to hypoxia. The pharmacological inhibition of DGK was associated with the diacylglycerol-dependent activation of PKC delta and epsilon and of their downstream target p38 MAPK. In conclusion, we unveil a novel signalling pathway contributing to the onset of hepatocyte preconditioning, which through RhoA-GTPase, couples A2aR to the downregulation of DGK. Such an inhibition is essential for the sustained accumulation of diacylglycerol required for triggering PKC-mediated survival signals.
    Cell death and differentiation 06/2010; 17(6):1059-68. · 8.24 Impact Factor
  • Journal of Hepatology 04/2010; 52. · 10.40 Impact Factor

Publication Stats

6k Citations
1,143.91 Total Impact Points


  • 1999–2014
    • Amedeo Avogadro University of Eastern Piedmont
      • Interdisciplinary Research Center of Autoimmune Diseases IRCAD
      Novara, Piedmont, Italy
  • 2007–2011
    • Azienda Ospedaliero Universitaria Maggiore della Carità
      • Department of Gastroenterology
      Novara, Piedmont, Italy
  • 2010
    • Ospedale Pediatrico Bambino Gesù
      Roma, Latium, Italy
  • 2004–2008
    • University of Arkansas at Little Rock
      Little Rock, Arkansas, United States
    • University of Arkansas for Medical Sciences
      • Department of Pharmacology and Toxicology
      Little Rock, AR, United States
  • 1993–1999
    • Karolinska Institutet
      • • Institutet för miljömedicin - IMM
      • • Institutionen för medicinsk biokemi och biofysik
      Solna, Stockholm, Sweden
  • 1983–1998
    • Università degli Studi di Torino
      • • Dipartimento di Scienze Chirurgiche
      • • Department of Medical Science
      Torino, Piedmont, Italy
  • 1997
    • Karolinska University Hospital
      Tukholma, Stockholm, Sweden
  • 1993–1997
    • Harbor-UCLA Medical Center
      • Department of Pediatrics
      Torrance, California, United States
  • 1994
    • Louisiana State University
      • Biodynamics Institute
      Baton Rouge, LA, United States
    • University of Pavia
      • Department of Internal Medicine and Therapeutics
      Pavia, Lombardy, Italy
  • 1980–1985
    • Brunel University London
      अक्सब्रिज, England, United Kingdom