Andrew D Clouston

University of Queensland, Brisbane, Queensland, Australia

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Publications (166)883.86 Total impact

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    ABSTRACT: The traditional serrated adenoma is the least common colorectal serrated polyp. The clinicopathological features and molecular drivers of these polyps require further investigation. We have prospectively collected a cohort of 200 ordinary and advanced traditional serrated adenomas and performed BRAF and KRAS mutational profiling, CpG island methylator phenotype analysis, and immunohistochemistry for a panel of 7 antibodies (MLH1, β-catenin, p53, p16, Ki67, CK7, and CK20) on all cases. The mean age of the patients was 64 years and 50% were female. Of the polyps, 71% were distal. Advanced histology (overt dysplasia or carcinoma) was present in 19% of cases. BRAF mutation was present in 67% and KRAS mutation in 22%. BRAF mutant traditional serrated adenomas were more frequently proximal (39% versus 2%; P≤0.0001), were exclusively associated with a precursor polyp (57% versus 0%; P≤0.0001), and were more frequently CpG island methylator phenotype high (60% versus 16%; P≤0.0001) than KRAS mutant traditional serrated adenomas. Advanced traditional serrated adenomas retained MLH1 expression in 97%, showed strong p53 staining in 55%, and nuclear β-catenin staining in 40%. P16 staining was lost in the advanced areas of 55% of BRAF mutant traditional serrated adenomas compared with 10% of the advanced areas of KRAS mutant or BRAF/KRAS wild-type traditional serrated adenomas. BRAF and KRAS mutant traditional serrated adenomas are morphologically related but biologically disparate polyps with distinctive clinicopathological and molecular features. The overwhelming majority of traditional serrated adenomas retain mismatch repair enzyme function indicating a microsatellite-stable phenotype. Malignant progression occurs via TP53 mutation and Wnt pathway activation regardless of mutation status. However, CDKN2A (encoding the p16 protein) is silenced nearly exclusively in the advanced areas of the BRAF mutant traditional serrated adenomas. Thus, the BRAF mutant traditional serrated adenoma represents an important precursor of the aggressive BRAF mutant, microsatellite-stable subtype of colorectal carcinoma.Modern Pathology advance online publication, 12 September 2014; doi:10.1038/modpathol.2014.122.
    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc. 09/2014;
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    ABSTRACT: Background: Fibrosis in liver with hepatitis C virus (HCV) recurrence post-liver transplantation (LT) can be rapidly progressive and the mechanisms underlying this process are poorly understood. In liver with HCV infection in the non-LT setting, there is a significant relationship between the development of structures known as the ductular reaction (DR), hepatic progenitor cells (HPCs) and fibrosis. In this study, we have characterized the DR, HPCs and fibrosis associated with HCV recurrence post-LT.Methods: Immunohistochemistry and confocal microscopy were used to characterize the DR, HPC and fibrosis in liver biopsy specimens. Key findings were confirmed in a separate independent cohort.Results: The initial characterization cohort had 194 biopsy samples from 105 individuals with HCV recurrence post-LT. The immunophenotype, morphology and location of the DR was consistent with an HPC origin. The DR correlated with intrahepatic fibrosis (rs=0.529, p<0.001) and numbers of activated hepatic stellate cells (HSCs, rs=0.446, p<0.001). There was an early occurrence of hepatocyte replicative arrest and increased hepatocyte proliferation that correlated with the DR (rs=0.295, p<0.001). Replicative arrest preceded hepatocyte proliferation in early stage injury. Hepatocyte proliferation decreased with advanced fibrosis, in contrast the extent of the DR and numbers of activated HSCs continued to increase. In the second cohort of 37 individuals, the DR and numbers of HPCs similarly correlated with fibrosis and inflammation post-LT.Conclusions: This is the first characterization of the DR in HCV-associated liver injury post-LT. There was a significant correlation between the DR and the development of progressive fibrosis in HCV recurrence. These results suggest a pivotal role for both the DR and HPC responses in the aggressive fibrosis seen with HCV recurrence post-LT. Liver Transpl , 2014. © 2014 AASLD.
    Liver Transplantation 09/2014; · 3.94 Impact Factor
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    ABSTRACT: Celiac disease (CeD) is a common gluten-sensitive autoimmune enteropathy. A gluten-free diet is an effective treatment, but compliance is demanding; hence, new treatment strategies for CeD are required.
    The Journal of allergy and clinical immunology. 08/2014;
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    ABSTRACT: Chronic GVHD (cGVHD) is the major cause of late, nonrelapse death following stem cell transplantation and characteristically develops in organs such as skin and lung. Here, we used multiple murine models of cGVHD to investigate the contribution of macrophage populations in the development of cGVHD. Using an established IL-17-dependent sclerodermatous cGVHD model, we confirmed that macrophages infiltrating the skin are derived from donor bone marrow (F4/80+CSF-1R+CD206+iNOS-). Cutaneous cGVHD developed in a CSF-1/CSF-1R-dependent manner, as treatment of recipients after transplantation with CSF-1 exacerbated macrophage infiltration and cutaneous pathology. Additionally, recipients of grafts from Csf1r-/- mice had substantially less macrophage infiltration and cutaneous pathology as compared with those receiving wild-type grafts. Neither CCL2/CCR2 nor GM-CSF/GM-CSFR signaling pathways were required for macrophage infiltration or development of cGVHD. In a different cGVHD model, in which bronchiolitis obliterans is a prominent manifestation, F4/80+ macrophage infiltration was similarly noted in the lungs of recipients after transplantation, and lung cGVHD was also IL-17 and CSF-1/CSF-1R dependent. Importantly, depletion of macrophages using an anti-CSF-1R mAb markedly reduced cutaneous and pulmonary cGVHD. Taken together, these data indicate that donor macrophages mediate the development of cGVHD and suggest that targeting CSF-1 signaling after transplantation may prevent and treat cGVHD.
    The Journal of clinical investigation. 08/2014;
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    ABSTRACT: Background and AimDevelopment of effective antifibrotic treatments which can be translated to clinical practice is an important challenge in contemporary hepatology. A recent report on β-thalassemia patients demonstrated that deferasirox treatment reversed or stabilized liver fibrosis independent of its iron chelating properties. In this study we investigated deferasirox in cell and animal models to better understand its potential antifibrotic effects.Methods The LX-2 stellate cell line was treated with 5μM or 50μM deferasirox (Exjade) for up to 120hr. Three week old multidrug resistance 2 null (Mdr2-/-) mice received oral deferasirox or vehicle for 4 weeks (30mg/kg/day). Cells and liver tissue were collected for assessment of fibrosis and fibrogenic gene expression.ResultsIn LX-2 cells treated with 50μM deferasirox for 12 hours α1(I)procollagen expression was decreased by 25%, with maximal reductions (10-fold) seen following 24-120 hours of treatment. Similarly, α-smooth muscle actin (αSMA) expression was significantly lower. Alterations in matrix remodelling genes, specifically decreased expression of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2, were observed. There was no significant difference in hepatic hydroxyproline content in Mdr2-/- mice following deferasirox administration (vehicle: 395±27μg/g vs. deferasirox: 421±33μg/g). Similarly, no changes in the expression of fibrogenic genes were observed.Conclusions Despite reductions in α1(I)procollagen and αSMA expression and alterations in matrix degradation genes in LX-2 cells, deferasirox did not exhibit antifibrotic activity in Mdr2-/- mice. Given the positive outcomes seen in human trials, it may be appropriate to study deferasirox in other animal models of fibrosis and/or for a longer duration of therapy.
    Journal of Gastroenterology and Hepatology 08/2014; · 3.33 Impact Factor
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    ABSTRACT: Background: Non-alcoholic steatohepatitis (NASH) is increasing in prevalence, yet the consequences for liver function are unknown. We studied ureagenesis, an essential metabolic liver function of importance for whole-body nitrogen homeostasis, in a rodent model of diet induced NASH. Methods: Rats were fed a high-fat, high-cholesterol diet for 4 and 16 weeks, resulting in early and advanced experimental NASH, respectively. We examined the urea cycle enzyme mRNAs in liver tissue, the hepatocyte urea cycle enzyme proteins and the in vivo Capacity of Urea-Nitrogen Synthesis (CUNS). Results: Early NASH decreased all the urea cycle mRNAs to an average of 60% and the ornithine transcarbamylase protein to 10% while the CUNS remained unchanged. Advanced NASH further decreased the carbamoyl phosphate synthetase protein to 63%, and in addition decreased the CUNS by 20% (from 5.65 ± 0.23 to 4.58 ± 0.30 μmol x (min x 100 g) -1; P = 0.01). Conclusion: Early NASH compromised the genes and enzyme proteins involved in ureagenesis, while advanced NASH resulted in a functional reduction in the capacity for ureagenesis. The pattern of urea cycle perturbations suggests a prevailing mitochondrial impairment by NASH. The decrease in CUNS has consequences for the ability of the body to adjust to changes in the requirements for nitrogen homeostasis e.g. at stressfull events. NASH, thus, in terms of metabolic consequences is not an innocuous lesion and the manifestations of the damage seem to be a continuum with increasing disease severity.
    American journal of physiology. Gastrointestinal and liver physiology. 06/2014;
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    ABSTRACT: Patients with non-alcoholic steatohepatitis (NASH) have increased mortality, including from infections. We, therefore, tested in a rodent model of steatohepatitis whether the hepatic acute phase response is intact. Steatohepatitis was induced in rats by feeding a high-fat, high-cholesterol diet for 4 (early) and 16 weeks (advanced NASH). 2 hours after low-dose LPS (0.5 mg/kg i.p.) we measured the serum concentrations of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). We also measured liver mRNA's and the serum concentrations of acute phase proteins 24 hours after LPS. NASH in itself increased the liver mRNA levels of TNF-α and IL-6 and also the liver mRNA and serum levels of the acute phase proteins. The exposure to LPS increased serum TNF-α in both early and advanced NASH and more so than in the control rats. However, the increases in acute phase protein genes in liver tissue and proteins in the blood were lower than in the control rats. In rats with early or advanced experimental NASH, LPS despite an increased interleukin release resulted in a blunted acute phase protein response. This tachyphylaxis may be part of the mechanism for the increased infection susceptibility of patients with NASH. We speculate that the steatosis-related interleukin release desensitizes the signalling pathway leading to acute phase protein synthesis. This article is protected by copyright. All rights reserved.
    Liver international: official journal of the International Association for the Study of the Liver 03/2014; · 3.87 Impact Factor
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    ABSTRACT: Mammalian target of rapamycin and angiotensin converting enzyme inhibition has been shown to have antifibrotic activity in models of liver fibrosis. The aim of our study was to determine the efficacy of rapamycin, everolimus, irbesartan and captopril, alone and in combination, as antifibrotic agents in the Mdr2(-/-) model of cholestasis both in early injury and established disease. Mdr2(-/-) mice were treated for 4 weeks with vehicle, rapamycin (1 mg/kg) or everolimus (5 mg/kg) every second day or with captopril (30mg/kg/day), irbesartan (10 mg/kg/day) or vehicle. Further groups of three week old Mdr2(-/-) mice were treated with rapamycin and irbesartan in combination (1 mg/kg/day and 10 mg/kg/day) or with rapamycin (2 mg/kg/day) for 4 weeks. Liver injury and fibrosis were compared between treated and untreated animals. There were no significant improvements in liver injury, histology, hepatic hydroxyproline or profibrogenic gene expression following treatment with rapamycin, everolimus, captopril or irbesartan at any time point studied. Likewise, there were no improvements in liver histology or profibrogenic gene expression following combination therapy or high-dose rapamycin treatment. The antifibrotic effects of rapamycin, everolimus, captopril and irbesartan seen in other models of fibrosis were not replicated in the Mdr2(-/-) model in this study. This highlights the clear need to test specific antifibrotic agents in a number of different animal models. We believe this animal model is ideal to study usefulness of antifibrotic agents in cholestatic liver disease because of the similarity in genetics and hepatic histopathology to human cholestatic liver disease. This article is protected by copyright. All rights reserved.
    Liver international: official journal of the International Association for the Study of the Liver 02/2014; · 3.87 Impact Factor
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    ABSTRACT: Non-alcoholic fatty liver disease (NAFLD) is a rapidly growing global health problem. It can be separated histologically into two broad groups: steatosis, which usually follows a benign clinical course and non-alcoholic steatohepatitis (NASH) that typically has hepatocyte ballooning, necroinflammatory activity and can progress to fibrosis and cirrhosis. More recently the histological spectrum has expanded with the recognition of a paediatric pattern of NASH that has portal-based inflammation and fibrosis without ballooning. An overlap pattern is also described. There is increasing interest in the portal changes of NASH as these correlate with the progression of fibrosis. Disease-associated hepatocyte senescence appears to trigger an alternative regenerative pathway and the development of a periportal ductular reaction (DR), which in turn may have a role in progressive fibrogenesis. Portal inflammation, particularly in association with the DR, is an area of recent study.
    Current Hepatitis Reports 02/2014;
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    ABSTRACT: The sessile serrated adenoma (SSA) is a relatively recently described polyp that can present diagnostic difficulties for the practicing pathologist. The frequency of SSA diagnoses varies dramatically in the reported literature. In addition, the histologic interface between the microvesicular hyperplastic polyp (MVHP) and the SSA continues to be a diagnostic problem. The trend in recent years has been toward a lower threshold for SSA diagnosis. Herein, we have performed a cross-sectional study of 6340 colorectal polyps received at a high-volume community-based pathology practice over a 3-month period. After central review, with strict application of the diagnostic criteria outlined in the 2010 edition of the World Health Organization Classification of Tumours of the Digestive Tract, we found that SSAs represented 12.1% of all polyps. In addition, we developed novel diagnostic subcategories in an attempt to determine the most appropriate cutoff for the interface between the MVHP and the SSA. We found that serrated polyps (MVHPs or SSAs) with any SSA-like crypts had clinical features more in common with the SSA than the MVHP and that this diagnostic cutoff showed good reproducibility between pathologists. This supports the position of a recent consensus publication proposing that polyps with as few as 1 SSA-type crypt should be diagnosed as an SSA. Applying these criteria to our cohort yields an overall SSA rate of 14.7%. In summary, we believe that SSAs continue to be underdiagnosed in pathologic practice and that this may result in inadequate surveillance and thus contribute to interval colorectal carcinomas.
    The American journal of surgical pathology 02/2014; 38(2):158-66. · 4.06 Impact Factor
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    ABSTRACT: The normal liver has three major closely integrated compartments: hepatocytes, the biliary system and the vascular system. The first comprises 70% of the cells; the biliary system communicates throughout and outside the liver with immediately adjacent extra-hepatic organs and the last is, in many ways, the most complex of all three systems. The vascular system also communicates outside and throughout the liver. This article is protected by copyright. All rights reserved.
    Histopathology 01/2014; · 2.86 Impact Factor
  • Human pathology 01/2014; 45(3):658–660. · 3.03 Impact Factor
  • Michael J Williams, Andrew D Clouston, Stuart J Forbes
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    ABSTRACT: Interactions between cells and their extracellular matrix have been shown to be crucial in a wide range of biological processes, including the proliferation and differentiation of stem cells. Ductular reactions containing both hepatic progenitor cells and extracellular matrix are seen in response to acute severe and chronic liver injury. Understanding the molecular mechanisms whereby cell-matrix interactions regulate liver regeneration may allow novel strategies to enhance this process. Both the ductular reaction in humans and hepatic progenitor cells in rodent models are closely associated with collagen and laminin, although there is still debate about cause and effect. Recent studies have demonstrated a requirement for matrix remodelling by matrix metalloproteinases for the proliferation of hepatic progenitor cells, and suggested defined roles for specific matrix components. Understanding the interactions between progenitor cells and matrix is critical for the development of novel regenerative and anti-fibrotic therapies.
    Gastroenterology 12/2013; · 12.82 Impact Factor
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    ABSTRACT: Although non-alcoholic fatty liver disease (NAFLD) is conventionally assessed histologically for lobular features of inflammation, the development of portal fibrosis appears to be associated with disease progression. We investigated the composition of the portal inflammatory infiltrate and its relationship to the ductular reaction (DR), a second portal phenomenon implicated in fibrogenesis. The portal inflammatory infiltrate may contribute directly to fibrogenesis as well as influence the fate of the DR hepatic progenitor cells (HPC), regulating the balance between liver repair and fibrosis. The presence of portal inflammation in NAFLD was strongly correlated with disease severity (fibrosis stage) and the DR. The portal infiltrate was characterised by immunostaining NAFLD liver biopsy sections (n=33) for broad leukocyte subset markers (CD68, CD3, CD8, CD4, CD20, neutrophil elastase) and selected inflammatory markers (Matrix Metalloproteinase-9, IL-17). Cells expressing all markers examined were identified throughout the liver lobules and in portal tracts, although portal tracts were more densely populated (P<0.01), and dominated by CD68+ macrophages and CD8+ lymphocytes, at all stages of disease. An increase in portal macrophages in NAFLD patients with steatosis alone (P<0.01) was the earliest change detected, even prior to elevated expression of the pro-inflammatory cytokines IL1B and TNF in patients with early NASH (P<0.05). Portal and peri-ductal accumulation of all other cell types examined occurred in progressed NASH (all P<0.05). Conclusion: Knowledge of the complex cellular composition of the portal inflammatory infiltrate and HPC/DR niche in NAFLD will shape future functional studies to elucidate the contribution of portal inflammation to HPC differentiation and NAFLD pathogenesis.
    Hepatology 11/2013; · 12.00 Impact Factor
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    ABSTRACT: Endoplasmic reticulum (ER) stress is an important pathogenic mechanism for alcoholic (ALD) and nonalcoholic fatty liver disease (NAFLD). Iron overload is an important cofactor for liver injury in ALD and NAFLD, but its role in ER stress and associated stress signaling pathways is unclear. To investigate this, we developed a murine model of combined liver injury by co-feeding the mildly iron overloaded, the hemochromatosis gene-null (Hfe(-/)) mouse ad libitum with ethanol and a high-fat diet (HFD) for 8 weeks. This co-feeding led to profound steatohepatitis, significant fibrosis, and increased apoptosis in the Hfe(-/-) mice as compared with wild-type (WT) controls. Iron overload also led to induction of unfolded protein response (XBP1 splicing, activation of IRE-1α and PERK, as well as sequestration of GRP78) and ER stress (increased CHOP protein expression) following HFD and ethanol. This is associated with a muted autophagic response including reduced LC3-I expression and impaired conjugation to LC3-II, reduced beclin-1 protein, and failure of induction of autophagy-related proteins (Atg) 3, 5, 7, and 12. As a result of the impaired autophagy, levels of the sequestosome protein p62 were most elevated in the Hfe(-/-) group co-fed ethanol and HFD. Iron overload reduces the activation of adenosine monophosphate protein kinase associated with ethanol and HFD feeding. We conclude that iron toxicity may modulate hepatic stress signaling pathways by impairing adaptive cellular compensatory mechanisms in alcohol- and obesity-induced liver injury.Laboratory Investigation advance online publication, 14 October 2013; doi:10.1038/labinvest.2013.121.
    Laboratory Investigation 10/2013; · 3.96 Impact Factor
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    ABSTRACT: Natural regulatory T cells (nTregs) play an important role in tolerance; however, the small numbers of cells obtainable potentially limit the feasibility of clinical adoptive transfer. Therefore, we studied the feasibility and efficacy of using murine-induced regulatory T cells (iTregs) for the induction of tolerance after bone marrow transplantation. iTregs could be induced in large numbers from conventional donor CD4 and CD8 T cells within 1 wk and were highly suppressive. During graft-versus-host disease (GVHD), CD4 and CD8 iTregs suppressed the proliferation of effector T cells and the production of proinflammatory cytokines. However, unlike nTregs, both iTreg populations lost Foxp3 expression within 3 wk in vivo, reverted to effector T cells, and exacerbated GVHD. The loss of Foxp3 in iTregs followed homeostatic and/or alloantigen-driven proliferation and was unrelated to GVHD. However, the concurrent administration of rapamycin, with or without IL-2/anti-IL-2 Ab complexes, to the transplant recipients significantly improved Foxp3 stability in CD4 iTregs (and, to a lesser extent, CD8 iTregs), such that they remained detectable 12 wk after transfer. Strikingly, CD4, but not CD8, iTregs could then suppress Teff proliferation and proinflammatory cytokine production and prevent GVHD in an equivalent fashion to nTregs. However, at high numbers and when used as GVHD prophylaxis, Tregs potently suppress graft-versus-leukemia effects and so may be most appropriate as a therapeutic modality to treat GVHD. These data demonstrate that CD4 iTregs can be produced rapidly in large, clinically relevant numbers and, when transferred in the presence of systemic rapamycin and IL-2, induce tolerance in transplant recipients.
    The Journal of Immunology 10/2013; · 5.52 Impact Factor
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    ABSTRACT: The development of portal fibrosis following the iron loading of hepatocytes is the first stage of fibrogenesis in hereditary haemochromatosis. In other chronic liver diseases it has been shown that a ductular reaction (DR) appears early, correlates with fibrosis progression and is a consequence of activation of an alternative pathway of hepatocyte replication. This study was designed to investigate the presence of the DR in haemochromatosis and describe its associations. Liver biopsies from 63 C282Y homozygous patients were assessed for hepatic iron concentration (HIC) and graded for iron loading, fibrosis stage, steatosis and inflammation. Immunostaining allowed quantification of the DR, hepatocyte senescence and proliferation and analysis incorporated clinical data. Hepatocyte senescence was positively correlated with HIC, serum ferritin and oxidative stress. A DR was demonstrated and occurred prior to histological fibrosis. HIC, age, hepatocyte senescence and proliferation, portal inflammation and excessive alcohol consumption all had significant associations with the extent of the DR. In multivariate analysis, iron loading, hepatocyte replicative arrest and portal inflammation remained independently and significantly associated with the DR. Of factors associated with fibrosis progression, the DR (OR 10.86 p<0.0001) and the presence of portal inflammation (OR 4.31, p=0.028) remained significant after adjustment for cofactors. The extent of the DR regressed following therapeutic venesection. Conclusion: Iron loading of hepatocytes leads to impaired replication, stimulating the development of the DR in haemochromatosis and this correlates strongly with hepatic fibrosis. Portal inflammation occurs in hemochromatosis and is independently associated with the DR and fibrosis, and thus its role in this disease should be evaluated further. (Hepatology 2013;).
    Hepatology 08/2013; · 12.00 Impact Factor
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    ABSTRACT: A reliable biomarker is required in hepatology clinics for detection and follow-up of heavy alcohol consumption. Carbohydrate-deficient transferrin (CDT) increases with sustained heavy alcohol consumption and is the most specific biomarker of ethanol (EtOH) consumption. Recent introduction of a standardized method for measuring CDT has improved its clinical application. This study was designed to determine whether alcohol-independent factors influence CDT levels in patients with chronic liver disease (CLD). The relationship between serum %CDT and self-reported history of alcohol consumption was examined in 254 patients referred for evaluation of liver disease. CDT analysis was performed on serum collected at time of liver biopsy. CDT levels were not affected by severity or etiology of nonalcoholic liver disease. Thirteen of 254 subjects had a %CDT >1.7, predictive of heavy alcohol intake, 6 of whom did not acknowledge heavy drinking. Twelve of these 13 subjects were suspected heavy drinkers on review of their medical records and clinical results. Conversely, not all acknowledged heavy drinkers had %CDT >1.7. Heavy drinkers with a body mass index (BMI) in the overweight or obese range had significantly lower %CDT than lean heavy drinkers. This persisted even when lean body weight was used as an approximation of the EtOH volume of distribution. An elevated BMI reduces the diagnostic utility of CDT at higher alcohol intake in subjects with CLD using the standardized method. In a hepatology outpatient setting, this assay is likely to be useful to confirm suspicion of heavy drinking in subjects who are not overweight, but cannot reliably identify moderate drinkers or heavy drinkers who are overweight.
    Alcoholism Clinical and Experimental Research 07/2013; · 3.42 Impact Factor
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    ABSTRACT: BACKGROUND: Combined iron overload and alcohol may promote synergistic chronic liver injury and toxicity. The role of specific dietary fats in influencing the development of co-toxic alcoholic liver disease needs further evaluation and is investigated in this study. METHODS: Wild-type (WT) and the iron-loaded Hfe-null (Hfe(-/-) ) mice were fed chow (CC), a AIN-93G standard control (SC), or a corn oil-modified, AIN-93G-based (CO) diet with or without the addition of 20% ethanol (EtOH) in the drinking water for 8 weeks and assessed for liver injury. RESULTS: WT mice on CC, SC, and CO diets had no liver injury, although mild steatosis developed in the SC and CO groups. The addition of EtOH resulted in mild steatohepatitis in WT mice fed SC but not those on a CO diet. EtOH administration in Hfe(-/-) animals on the CC and SC diets caused marked oxidative stress, inflammatory activity, and subsinusoidal and portal-portal tract linkage fibrosis with significant up-regulation of genes involved in cellular stress signaling and fibrogenic pathways. These effects were abrogated in the CO-fed mice, despite elevated serum EtOH levels and hepatic iron concentrations, reduced hepatic glutathione and mitochondrial superoxide dismutase activities. Feeding with the CO diet led to increased hepatic glutathione peroxidase and catalase activities and attenuated alcohol-induced hepatic steatosis in the Hfe(-/-) animals. Iron and EtOH feeding markedly reduced p-STAT3 and p-AMPK protein levels, but this effect was significantly attenuated when a CO diet was consumed. CONCLUSIONS: A CO-based diet is protective against combined EtOH- and iron-induced liver toxicity, likely via attenuation of hepatic steatosis and oxidative stress and may have a role in the prevention of fibrosis development in chronic liver disease.
    Alcoholism Clinical and Experimental Research 06/2013; · 3.42 Impact Factor
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    ABSTRACT: Donor T cells play pivotal roles in graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effects following bone marrow transplantation (BMT). DNAX accessory molecule 1 (DNAM-1) is a co-stimulatory and adhesion molecule, expressed mainly by NK cells and CD8(+) T cells at steady state to promote adhesion to ligand-expressing targets and enhance cytolysis. We have analyzed the role of this pathway in GVHD and GVL. The absence of DNAM-1 on the donor graft attenuated GVHD in MHC-mismatched and MHC-matched BMT following conditioning with lethal and sublethal irradiation. In contrast, DNAM-1 was not critical for GVL effects against ligand (CD155)-expressing and non-expressing leukemia. The effects on GVHD following myeloablative conditioning were independent of CD8(+) T cells and dependent on CD4(+) T, and specifically donor FoxP3(+) regulatory T cells (T(reg)). The absence of DNAM-1 promoted the expansion and suppressive function of T(reg) after BMT. These findings provide support for therapeutic DNAM-1 inhibition to promote tolerance in relevant inflammatory based diseases characterized by T cell activation.
    Blood 02/2013; · 9.78 Impact Factor

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883.86 Total Impact Points

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  • 1997–2014
    • University of Queensland
      • • Centre for Liver Disease Research
      • • School of Medicine
      • • Department of Medicine
      • • Department of Surgery
      • • Princess Alexandra Hospital
      Brisbane, Queensland, Australia
  • 2001–2013
    • Queensland Institute of Medical Research
      • Bone Marrow Transplantation Laboratory
      Brisbane, Queensland, Australia
  • 1993–2013
    • Princess Alexandra Hospital (Queensland Health)
      • • Division of Medicine
      • • Division of Surgery
      Brisbane, Queensland, Australia
  • 2004–2012
    • University of Southern Queensland 
      Toowoomba, Queensland, Australia
  • 2009
    • Wesley Hospital
      Brisbane, Queensland, Australia
    • Peter MacCallum Cancer Centre
      • Surgery Division
      Melbourne, Victoria, Australia
  • 2005
    • University of Pittsburgh
      • Department of Medicine
      Pittsburgh, Pennsylvania, United States
  • 2002
    • Sullivan Nicolaides Pathology
      Taringa, Queensland, Australia