John Olynyk - Academia.edu (original) (raw)
Papers by John Olynyk
BMC Cancer, 2018
Background: Cancer risk is associated with serum iron levels. The aim of this study was to evalua... more Background: Cancer risk is associated with serum iron levels. The aim of this study was to evaluate whether haematological parameters reflect serum iron levels and may also be associated with cancer risk. Methods: We studied 1564 men and 1769 women who were enrolled in the Busselton Health Study, Western Australia. Haematological parameters evaluated included haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC) and red cell distribution width (RCDW). Statistical analyses included t-tests for quantitative variables, chi-square tests for categorical variables and Cox proportional hazards regression modelling for cancer incidence and death. Results: There was marginal evidence of an association between MCV (as a continuous variable) and non-skin cancer incidence in women (HR 1.15, 95% CI 1.013, 1.302; p = 0.030) but the hazard ratio was attenuated to nonsignificance after adjustment for serum ferritin (SF), iron and transferrin saturation (TS) (HR 1.11, 95% CI 0.972, 1.264; p = 0.126). There was strong evidence of an association between MCHC and prostate cancer incidence in men; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.27 (95% CI 1.064, 1.507; p = 0.008). These results remained significant after further adjustment for SF and iron; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.25 (p = 0.014, 95% CI 1.05 to 1.48). Conclusions: The MCHC and MCV were associated with cancer incidence in a Western Australian population, although only MCHC remained associated with prostate cancer after adjusting with serum iron and TS (circulating iron) and SF (storage iron). Haematological parameters are thus of limited utility in population profiling for future cancer risk.
Postgraduate medicine, 1994
Preview Hereditary hemochromatosis, once believed to be rare, is now known to affect 1 in 250 to ... more Preview Hereditary hemochromatosis, once believed to be rare, is now known to affect 1 in 250 to 300 people of northern European descent. Untreated, the disorder can have serious complications, but for patients in whom it is discovered and treated early, the prognosis is good. In this guide to diagnosis and management, Drs Olynyk and Bacon discuss, among other things, which patients to screen, what tests to order, length of treatment, effect of treatment on complications, and prognosis.
Hemodialysis International, 2017
Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis... more Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis patients and parenteral Fe is routinely used to treat this condition in conjunction with erythropoiesis stimulating agents. While restoration of hemoglobin toward the target range is a good outcome of Fe replacement, it is well known that Fe overload and toxicity may be adverse consequences of this therapy. Dialysis clinical practice guidelines recommend tailoring Fe therapy based on transferrin saturation and serum ferritin levels. Unfortunately, serum Fe markers may not accurately reflect the amount of Fe in the body, because factors such as infections, inflammation, or malignancy can alter serum ferritin levels. Some recent trials in dialysis patients receiving high intravenous Fe doses have shown increased cardiovascular morbidity and mortality and studies using magnetic resonance imaging (MRI) in this population have shown excessive tissue liver iron content (LIC) suggesting Fe overload. While LIC measured by MRI correlates well with LIC quantitated by liver biopsy, it only represents a surrogate marker for total body Fe and its clinical relevance in dialysis patients in terms of mortality and morbidity remains to be demonstrated. Nevertheless, these recent findings challenge the use of current serum Fe markers recommended by clinical guidelines to guide safe Fe therapy in dialysis patients. While not yet established for the routine screening of dialysis patients for Fe overload, MRI should be considered in patients who have received a high cumulative dose of intravenous Fe, or have long cumulative dialysis vintage. Further studies are needed to assess how MRI will alter management.
Rare Diseases, 2016
A. Milward (2016) Pathological relationships involving iron and myelin may constitute a shared me... more A. Milward (2016) Pathological relationships involving iron and myelin may constitute a shared mechanism linking various rare and common brain diseases, Rare Diseases, 4:1, e1198458,
The American journal of pathology, Jul 12, 2016
Complications of end-stage chronic liver disease signify a major cause of mortality worldwide. Ir... more Complications of end-stage chronic liver disease signify a major cause of mortality worldwide. Irrespective of the underlying cause, most chronic liver diseases are characterized by hepatocellular necrosis, inflammation, fibrosis, and proliferation of liver progenitor cells or ductular reactions. Vast differences exist between experimental models that mimic these processes, and their identification is fundamental for translational research. We compared two common murine models of chronic liver disease: the choline-deficient, ethionine-supplemented (CDE) diet versus thioacetamide (TAA) supplementation. Markers of liver injury, including serum alanine transaminase levels, apoptosis, hepatic fat loading, and oxidative stress, as well as inflammatory, fibrogenic and liver progenitor cell responses, were assessed at days 3, 7, 14, 21, and 42. This study revealed remarkable differences between the models. It identified periportal injury and fibrosis with an early peak and slow normalizati...
Biochimica et biophysica acta, 2016
Essential metals, such as iron and copper, play a critical role in a plethora of cellular process... more Essential metals, such as iron and copper, play a critical role in a plethora of cellular processes including cell growth and proliferation. However, concomitantly, excess of these metal ions in the body can have deleterious effects due to their ability to generate cytotoxic reactive oxygen species (ROS). Thus, the human body has evolved a very well-orchestrated metabolic system that keeps tight control on the levels of these metal ions. Considering their very high proliferation rate, cancer cells require a high abundance of these metal compared to their normal counterparts. Interestingly, new anti-cancer agents have been developed that take advantage of the sensitivity of cancer cells to metal sequestration and their susceptibility to ROS. These ligands can avidly bind metals ions to form redox active metal complexes, which lead to generation of cytotoxic ROS. Furthermore, these agents also act as potent metastasis suppressors due to their ability to up-regulate the metastasis supp...
Nephrology (Carlton, Vic.), Jan 29, 2016
Parenteral iron is integral in the treatment of anaemia of chronic kidney disease (CKD) patients ... more Parenteral iron is integral in the treatment of anaemia of chronic kidney disease (CKD) patients on haemodialysis (HD). However, increased liver iron concentration (LIC) can result from such treatment and this correlates poorly with serum ferritin or transferrin saturation values. It is unclear whether increased cardiac iron concentration also occurs in this setting. We aimed to evaluate the relationship of intravenous iron supplementation to hepatic and cardiac iron deposition in chronic HD subjects. A cohort of 10 patients on chronic HD for at least 1 year underwent MRI-based quantitation of hepatic and cardiac iron content to evaluate the relationship between intravenous iron supplements and hepatic and cardiac iron deposition. The results were compared against the cumulative parenteral iron dose and serum iron markers. The median age was 61 years (95% confidence interval (CI) 50 - 71), HD time 2.5 years (95%CI 2.0-5.3) and cumulative iron dose 4300mg (95%CI 2110-9045). Hepatic i...
American journal of physiology. Gastrointestinal and liver physiology, Jan 25, 2015
The growing worldwide challenge of cirrhosis and hepatocellular carcinoma due to increasing preva... more The growing worldwide challenge of cirrhosis and hepatocellular carcinoma due to increasing prevalence of excessive alcohol consumption, viral hepatitis, obesity and the metabolic syndrome has sparked interest in stem cell-like liver progenitor cells (LPCs) as potential candidates for cell therapy and tissue engineering as an alternative approach to whole organ transplantation. However LPCs always proliferate in chronic liver diseases with a predisposition to cancer; they have been suggested to play major roles in driving fibrosis, disease progression and may even represent tumour-initiating cells. Hence, a greater understanding of the factors that govern their activation, communication with other hepatic cell types and bipotential differentiation as opposed to their potential transformation is needed before their therapeutic potential can be harnessed.
BMJ open, Jan 12, 2015
HFE p.C282Y homozygosity is the most common cause of hereditary haemochromatosis. There is curren... more HFE p.C282Y homozygosity is the most common cause of hereditary haemochromatosis. There is currently insufficient evidence to assess whether non-specific symptoms or hepatic injury in homozygotes with moderately elevated iron defined as a serum ferritin (SF) of 300-1000 µg/L are related to iron overload. As such the evidence for intervention in this group is lacking. We present here methods for a study that aims to evaluate whether non-specific symptoms and hepatic fibrosis markers improve with short-term normalisation of SF in p.C282Y homozygotes with moderate elevation of SF. Mi-iron is a prospective, multicentre, randomised patient-blinded trial conducted in three centres in Victoria and Queensland, Australia. Participants who are HFE p.C282Y homozygotes with SF levels between 300 and 1000 μg/L are recruited and randomised to either the treatment group or to the sham treatment group. Those in the treatment group have normalisation of SF by 3-weekly erythrocytapheresis while those...
Journal of hepatology, Jan 31, 2015
The American journal of pathology, 1998
Liver injury due to bile duct ligation (BDL) is histologically characterized by cholestasis, bile... more Liver injury due to bile duct ligation (BDL) is histologically characterized by cholestasis, bile ductular proliferation, hepatocellular damage, portal fibrosis, and ultimately biliary cirrhosis. Stem cells within the liver may act as progenitor cells for small epithelial cells termed oval cells that can differentiate into bile duct cells or hepatocytes, whereas myofibroblasts are the principal source of collagen production in fibrosis. The aims of this study were to determine 1) whether BDL induces oval cell proliferation and 2) whether blockade of Kupffer cells affects oval cell proliferation, bile duct proliferation, and myofibroblast transformation in experimental biliary obstruction. Male Sprague-Dawley rats were divided into two groups to receive either a single dose of gadolinium chloride (a selective Kupffer cell blocking agent) or vehicle. One day later, the gadolinium- and vehicle-treated groups were further subdivided to receive either BDL or sham operation. The rats were...
Hepatology, 2015
Iron is implicated in the pathogenesis of liver injury and insulin resistance (IR) and thus phleb... more Iron is implicated in the pathogenesis of liver injury and insulin resistance (IR) and thus phlebotomy has been proposed as a treatment for nonalcoholic fatty liver disease (NAFLD). We performed a prospective 6-month randomized, controlled trial examining the impact of phlebotomy on the background of lifestyle advice in patients with NAFLD. Primary endpoints were hepatic steatosis (HS; quantified by magnetic resonance imaging) and liver injury (determined by alanine aminotransaminase [ALT] and cytokeratin-18 [CK-18]). Secondary endpoints included insulin resistance measured by the insulin sensitivity index (ISI) and homeostasis model of assessment (HOMA), and systemic lipid peroxidation determined by plasma F2-isoprostane levels. A total of 74 subjects were randomized (33 phlebotomy and 41 control). The phlebotomy group underwent a median (range) of 7 (1-19) venesection sessions and had a significantly greater reduction in ferritin levels over 6 months, compared to controls (-148 ± 114 vs. -38 ± 89 ng/mL; P < 0.001). At 6 months, there was no difference between phlebotomy and control groups in HS (17.7% vs. 15.5%; P = 0.4), serum ALT (36 vs. 46 IU/L; P = 0.4), or CK-18 levels (175 vs. 196 U/L; P = 0.9). Similarly, there was no difference in end-of-study ISI (2.5 vs. 2.7; P = 0.9), HOMA (3.2 vs. 3.2; P = 0.6), or F2-isoprostane levels (1,332 vs. 1,190 pmmol/L; P = 0.6) between phlebotomy and control groups. No differences in any endpoint were noted in patients with hyperferritinemia at baseline. Among patients undergoing phlebotomy, there was no correlation between number of phlebotomy sessions and change in HS, liver injury, or IR from baseline to end of study. Reduction in ferritin by phlebotomy does not improve liver enzymes, hepatic fat, or IR in subjects with NAFLD. (Hepatology 2014).
Stem Cells and Development, 2010
Non-tumorous liver tissue removed during surgery to resect hepatocellular carcinoma (HCC) is pote... more Non-tumorous liver tissue removed during surgery to resect hepatocellular carcinoma (HCC) is potentially a useful source of material from which cells, particularly liver progenitor/stem cells (LPCs), can be isolated to establish cell lines. The purpose of this study was to evaluate the applicability of the "plate-and-wait" method to derive LPCs from resections to remove HCC. Three independent non-tumorous liver samples from HCC resection and 3 samples from liver donors were used for LPC isolation. Staining for LPC markers, OV6, CK19, and EpCAM, in the above liver samples demonstrated staining in only 2 of the non-tumorous samples. We isolated 2 human liver epithelial cell lines (HLECs) from these 2 samples. These HLECs were positive for general stem cell markers CD133, EpCAM, and Oct4. They expressed the liver progenitor cell markers OV6, CK14, and M2PK but not CK19. They also expressed the hepatocellular markers albumin, CK8, CK18, HNF4-α, and the drug-metabolizing gene CYP3A4. These cells accumulated glycogen, indocyanine green, and synthesized urea. They produced colonies in soft agar that showed anchorage-independent growth and their tumorigenic status was confi rmed when they produced tumors following transfer to athymic nude mice. In contrast, the third nontumorous tissue and 3 normal liver samples did not produce cell lines. This study establishes a correlation between the presence of LPCs in the source liver tissue and the ability to derive cell lines from these tissues. The phenotypic similarities between the LPCs and the HLECs suggest that a precursor-product relationship may exist between the 2 cell types.
Hepatology, 2005
Inflammation influences iron balance in the whole organism. A common clinical manifestation of th... more Inflammation influences iron balance in the whole organism. A common clinical manifestation of these changes is anemia of chronic disease (ACD; also called anemia of inflammation). Inflammation reduces duodenal iron absorption and increases macrophage iron retention, resulting in low serum iron concentrations (hyposideremia). Despite the protection hyposideremia provides against proliferating microorganisms, this "iron withholding" reduces the iron available to maturing red blood cells and eventually contributes to the development of anemia. Hepcidin antimicrobial peptide (Hamp) is a hepatic defensin-like peptide hormone that inhibits duodenal iron absorption and macrophage iron release. Hamp is part of the type II acute phase response and is thought to have a crucial regulatory role in sequestering iron in the context of ACD. Mice with deficiencies in the hemochromatosis gene product, Hfe, mounted a general inflammatory response after injection of lipopolysaccharide but lacked appropriate Hamp expression and did not develop hyposideremia. These data suggest a previously unidentified role for Hfe in innate immunity and ACD.
Hepatology, 2008
Lymphotoxin-beta (LT) is a proinflammatory cytokine and a member of the tumor necrosis factor (T... more Lymphotoxin-beta (LT) is a proinflammatory cytokine and a member of the tumor necrosis factor (TNF) superfamily known for its role in mediating lymph node development and homeostasis. Our recent studies suggest a role for LT in mediating the pathogenesis of human chronic liver disease. We hypothesize that LT coordinates the wound healing response in liver injury via direct effects on hepatic stellate cells. This study used the choline-deficient, ethionine-supplemented (CDE) dietary model of chronic liver injury, which induces inflammation, liver progenitor cell proliferation, and portal fibrosis, to assess (1) the cellular expression of LT, and (2) the role of LT receptor (LTR) in mediating wound healing, in LTR ؊/؊ versus wild-type mice. In addition, primary isolates of hepatic stellate cells were treated with LTR-ligands LT and LT-related inducible ligand competing for glycoprotein D binding to herpesvirus entry mediator on T cells (LIGHT), and mediators of hepatic stellate cell function and fibrogenesis were assessed. LT was localized to progenitor cells immediately adjacent to activated hepatic stellate cells in the periportal region of the liver in wild-type mice fed the CDE diet. LTR ؊/؊ mice fed the CDE diet showed significantly reduced fibrosis and a dysregulated immune response. LTR was demonstrated on isolated hepatic stellate cells, which when stimulated by LT and LIGHT, activated the nuclear factor kappa B (NF-B) signaling pathway. Neither LT nor LIGHT had any effect on alpha-smooth muscle actin, tissue inhibitor of metalloproteinase 1, transforming growth factor beta, or procollagen ␣ 1 (I) expression; however, leukocyte recruitmentassociated factors intercellular adhesion molecule 1 and regulated upon activation T cells expressed and secreted (RANTES) were markedly up-regulated. RANTES caused the chemotaxis of a liver progenitor cell line expressing CCR5. Conclusion: This study suggests that LTR on hepatic stellate cells may be involved in paracrine signaling with nearby LT-expressing liver progenitor cells mediating recruitment of progenitor cells, hepatic stellate cells, and leukocytes required for wound healing and regeneration during chronic liver injury. (HEPATOLOGY 2009;49:227-239.
European Journal of Cardiovascular Prevention & Rehabilitation, 2002
Background Increased iron stores and haemochromatosis gene mutations may be risk factors for coro... more Background Increased iron stores and haemochromatosis gene mutations may be risk factors for coronary heart disease. The aims of this study were to determine in a stable community population whether increased iron stores or haemochromatosis gene mutations were risk factors for coronary heart disease. Design Cross-sectional and prospective cohort studies. Methods We evaluated 1185 men and 1141 women aged 20-79 years of predominantly Anglo-Celtic descent from the 1994-95 assessment of the Busselton population in Western Australia. Subjects underwent haemochromatosis genotyping, serum iron studies, clinical, biochemical and ECG evaluation for coronary heart disease and associated risk factors. Hospital admissions or death from cardiovascular disease were determined by linkage with the Western Australian morbidity and mortality database. The study design was cross-sectional for the 1994-95 cohort comparing coronary heart disease cases with unaffected subjects and unaffected subjects were followed prospectively until December 1998. Results Cross-sectional and prospective cohort analyses demonstrated that elevated serum iron parameters or possession of either the C282Y or H63D mutations in the HFE gene were not predictive of increased risk for coronary heart disease in men or women. Conclusions Increased iron stores or haemochromatosis gene mutations are not significant risk factors for coronary heart disease.
Clinical Gastroenterology and Hepatology, 2014
Author contributions: EJM: study concept, statistical analysis and interpretation of data, drafti... more Author contributions: EJM: study concept, statistical analysis and interpretation of data, drafting of the manuscript and critical revision; ER: study concept, acquisition of data, interpretation of data, drafting of the manuscript and critical revision; JPB: acquisition of data, critical revision of manuscript; DT study concept, interpretation of data, critical revision of manuscript; JKO: study concept and oversight, interpretation of data, drafting of the manuscript and critical revision. Writing Assistance: NA Disclosures: No potential conflicts of interest to disclose by any author.
Carcinogenesis, 2005
Multifaceted evidence links the development of liver tumours to the activation and proliferation ... more Multifaceted evidence links the development of liver tumours to the activation and proliferation of adult liver progenitor (oval) cells during the early stages of chronic liver injury. The aim of this study was to examine the role of the peroxisome proliferator activated receptors (PPARs): PPARa, d and g, in mediating the behaviour of liver progenitor cells during pre-neoplastic disease and to investigate their potential as therapeutic targets for the treatment of chronic liver injury. We observed increased liver expression of PPARa and g in concert with expanding oval cell numbers during the first 21 days following commencement of the choline deficient, ethionine supplemented (CDE) dietary model of carcinogenic liver injury in mice. Both primary and immortalized liver progenitor cells were found to express PPARa, d and g, but not g2, the alternate splice form of PPARg. WY14643 (PPARa agonist), GW501516 (PPARd agonist) and ciglitazone (PPARg agonist) were tested for their ability to modulate the behaviour of p53-immortalized liver (PIL) progenitor cell lines in vitro. Both PPARd and g agonists induced dose-dependent growth inhibition and apoptosis of PIL cells. In contrast, the PPARa agonist had no effect on PIL cell growth. None of the drugs affected the maturation of PIL cells along either the hepatocytic or biliary lineages, as judged by their patterns of hepatic gene expression prior to and following treatment. Administration of the PPARg agonist ciglitazone to mice fed with the CDE diet for 14 days resulted in a significantly diminished oval cell response and decreased fibrosis compared with those receiving placebo. In contrast, GW501516 did not affect oval cell numbers or liver fibrosis, but inhibited CDE-induced hepatic steatosis. In summary, PPARg agonists reduce oval cell proliferation and fibrosis during chronic liver injury and may be useful in the prevention of hepatocellular carcinoma.
BMC Medical Genetics, 2008
Background: We report our experience of selecting tag SNPs in 35 genes involved in iron metabolis... more Background: We report our experience of selecting tag SNPs in 35 genes involved in iron metabolism in a cohort study seeking to discover genetic modifiers of hereditary hemochromatosis. Methods: We combined our own and publicly available resequencing data with HapMap to maximise our coverage to select 384 SNPs in candidate genes suitable for typing on the Illumina platform. Results: Validation/design scores above 0.6 were not strongly correlated with SNP performance as estimated by Gentrain score. We contrasted results from two tag SNP selection algorithms, LDselect and Tagger. Varying r 2 from 0.5 to 1.0 produced a near linear correlation with the number of tag SNPs required. We examined the pattern of linkage disequilibrium of three levels of resequencing coverage for the transferrin gene and found HapMap phase 1 tag SNPs capture 45% of the ≥ 3% MAF SNPs found in SeattleSNPs where there is nearly complete resequencing. Resequencing can reveal adjacent SNPs (within 60 bp) which may affect assay performance. We report the number of SNPs present within the region of six of our larger candidate genes, for different versions of stock genotyping assays. Conclusion: A candidate gene approach should seek to maximise coverage, and this can be improved by adding to HapMap data any available sequencing data. Tag SNP software must be fast and flexible to data changes, since tag SNP selection involves iteration as investigators seek to satisfy the competing demands of coverage within and between populations, and typability on the technology platform chosen.
BMC Cancer, 2018
Background: Cancer risk is associated with serum iron levels. The aim of this study was to evalua... more Background: Cancer risk is associated with serum iron levels. The aim of this study was to evaluate whether haematological parameters reflect serum iron levels and may also be associated with cancer risk. Methods: We studied 1564 men and 1769 women who were enrolled in the Busselton Health Study, Western Australia. Haematological parameters evaluated included haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC) and red cell distribution width (RCDW). Statistical analyses included t-tests for quantitative variables, chi-square tests for categorical variables and Cox proportional hazards regression modelling for cancer incidence and death. Results: There was marginal evidence of an association between MCV (as a continuous variable) and non-skin cancer incidence in women (HR 1.15, 95% CI 1.013, 1.302; p = 0.030) but the hazard ratio was attenuated to nonsignificance after adjustment for serum ferritin (SF), iron and transferrin saturation (TS) (HR 1.11, 95% CI 0.972, 1.264; p = 0.126). There was strong evidence of an association between MCHC and prostate cancer incidence in men; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.27 (95% CI 1.064, 1.507; p = 0.008). These results remained significant after further adjustment for SF and iron; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.25 (p = 0.014, 95% CI 1.05 to 1.48). Conclusions: The MCHC and MCV were associated with cancer incidence in a Western Australian population, although only MCHC remained associated with prostate cancer after adjusting with serum iron and TS (circulating iron) and SF (storage iron). Haematological parameters are thus of limited utility in population profiling for future cancer risk.
Postgraduate medicine, 1994
Preview Hereditary hemochromatosis, once believed to be rare, is now known to affect 1 in 250 to ... more Preview Hereditary hemochromatosis, once believed to be rare, is now known to affect 1 in 250 to 300 people of northern European descent. Untreated, the disorder can have serious complications, but for patients in whom it is discovered and treated early, the prognosis is good. In this guide to diagnosis and management, Drs Olynyk and Bacon discuss, among other things, which patients to screen, what tests to order, length of treatment, effect of treatment on complications, and prognosis.
Hemodialysis International, 2017
Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis... more Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis patients and parenteral Fe is routinely used to treat this condition in conjunction with erythropoiesis stimulating agents. While restoration of hemoglobin toward the target range is a good outcome of Fe replacement, it is well known that Fe overload and toxicity may be adverse consequences of this therapy. Dialysis clinical practice guidelines recommend tailoring Fe therapy based on transferrin saturation and serum ferritin levels. Unfortunately, serum Fe markers may not accurately reflect the amount of Fe in the body, because factors such as infections, inflammation, or malignancy can alter serum ferritin levels. Some recent trials in dialysis patients receiving high intravenous Fe doses have shown increased cardiovascular morbidity and mortality and studies using magnetic resonance imaging (MRI) in this population have shown excessive tissue liver iron content (LIC) suggesting Fe overload. While LIC measured by MRI correlates well with LIC quantitated by liver biopsy, it only represents a surrogate marker for total body Fe and its clinical relevance in dialysis patients in terms of mortality and morbidity remains to be demonstrated. Nevertheless, these recent findings challenge the use of current serum Fe markers recommended by clinical guidelines to guide safe Fe therapy in dialysis patients. While not yet established for the routine screening of dialysis patients for Fe overload, MRI should be considered in patients who have received a high cumulative dose of intravenous Fe, or have long cumulative dialysis vintage. Further studies are needed to assess how MRI will alter management.
Rare Diseases, 2016
A. Milward (2016) Pathological relationships involving iron and myelin may constitute a shared me... more A. Milward (2016) Pathological relationships involving iron and myelin may constitute a shared mechanism linking various rare and common brain diseases, Rare Diseases, 4:1, e1198458,
The American journal of pathology, Jul 12, 2016
Complications of end-stage chronic liver disease signify a major cause of mortality worldwide. Ir... more Complications of end-stage chronic liver disease signify a major cause of mortality worldwide. Irrespective of the underlying cause, most chronic liver diseases are characterized by hepatocellular necrosis, inflammation, fibrosis, and proliferation of liver progenitor cells or ductular reactions. Vast differences exist between experimental models that mimic these processes, and their identification is fundamental for translational research. We compared two common murine models of chronic liver disease: the choline-deficient, ethionine-supplemented (CDE) diet versus thioacetamide (TAA) supplementation. Markers of liver injury, including serum alanine transaminase levels, apoptosis, hepatic fat loading, and oxidative stress, as well as inflammatory, fibrogenic and liver progenitor cell responses, were assessed at days 3, 7, 14, 21, and 42. This study revealed remarkable differences between the models. It identified periportal injury and fibrosis with an early peak and slow normalizati...
Biochimica et biophysica acta, 2016
Essential metals, such as iron and copper, play a critical role in a plethora of cellular process... more Essential metals, such as iron and copper, play a critical role in a plethora of cellular processes including cell growth and proliferation. However, concomitantly, excess of these metal ions in the body can have deleterious effects due to their ability to generate cytotoxic reactive oxygen species (ROS). Thus, the human body has evolved a very well-orchestrated metabolic system that keeps tight control on the levels of these metal ions. Considering their very high proliferation rate, cancer cells require a high abundance of these metal compared to their normal counterparts. Interestingly, new anti-cancer agents have been developed that take advantage of the sensitivity of cancer cells to metal sequestration and their susceptibility to ROS. These ligands can avidly bind metals ions to form redox active metal complexes, which lead to generation of cytotoxic ROS. Furthermore, these agents also act as potent metastasis suppressors due to their ability to up-regulate the metastasis supp...
Nephrology (Carlton, Vic.), Jan 29, 2016
Parenteral iron is integral in the treatment of anaemia of chronic kidney disease (CKD) patients ... more Parenteral iron is integral in the treatment of anaemia of chronic kidney disease (CKD) patients on haemodialysis (HD). However, increased liver iron concentration (LIC) can result from such treatment and this correlates poorly with serum ferritin or transferrin saturation values. It is unclear whether increased cardiac iron concentration also occurs in this setting. We aimed to evaluate the relationship of intravenous iron supplementation to hepatic and cardiac iron deposition in chronic HD subjects. A cohort of 10 patients on chronic HD for at least 1 year underwent MRI-based quantitation of hepatic and cardiac iron content to evaluate the relationship between intravenous iron supplements and hepatic and cardiac iron deposition. The results were compared against the cumulative parenteral iron dose and serum iron markers. The median age was 61 years (95% confidence interval (CI) 50 - 71), HD time 2.5 years (95%CI 2.0-5.3) and cumulative iron dose 4300mg (95%CI 2110-9045). Hepatic i...
American journal of physiology. Gastrointestinal and liver physiology, Jan 25, 2015
The growing worldwide challenge of cirrhosis and hepatocellular carcinoma due to increasing preva... more The growing worldwide challenge of cirrhosis and hepatocellular carcinoma due to increasing prevalence of excessive alcohol consumption, viral hepatitis, obesity and the metabolic syndrome has sparked interest in stem cell-like liver progenitor cells (LPCs) as potential candidates for cell therapy and tissue engineering as an alternative approach to whole organ transplantation. However LPCs always proliferate in chronic liver diseases with a predisposition to cancer; they have been suggested to play major roles in driving fibrosis, disease progression and may even represent tumour-initiating cells. Hence, a greater understanding of the factors that govern their activation, communication with other hepatic cell types and bipotential differentiation as opposed to their potential transformation is needed before their therapeutic potential can be harnessed.
BMJ open, Jan 12, 2015
HFE p.C282Y homozygosity is the most common cause of hereditary haemochromatosis. There is curren... more HFE p.C282Y homozygosity is the most common cause of hereditary haemochromatosis. There is currently insufficient evidence to assess whether non-specific symptoms or hepatic injury in homozygotes with moderately elevated iron defined as a serum ferritin (SF) of 300-1000 µg/L are related to iron overload. As such the evidence for intervention in this group is lacking. We present here methods for a study that aims to evaluate whether non-specific symptoms and hepatic fibrosis markers improve with short-term normalisation of SF in p.C282Y homozygotes with moderate elevation of SF. Mi-iron is a prospective, multicentre, randomised patient-blinded trial conducted in three centres in Victoria and Queensland, Australia. Participants who are HFE p.C282Y homozygotes with SF levels between 300 and 1000 μg/L are recruited and randomised to either the treatment group or to the sham treatment group. Those in the treatment group have normalisation of SF by 3-weekly erythrocytapheresis while those...
Journal of hepatology, Jan 31, 2015
The American journal of pathology, 1998
Liver injury due to bile duct ligation (BDL) is histologically characterized by cholestasis, bile... more Liver injury due to bile duct ligation (BDL) is histologically characterized by cholestasis, bile ductular proliferation, hepatocellular damage, portal fibrosis, and ultimately biliary cirrhosis. Stem cells within the liver may act as progenitor cells for small epithelial cells termed oval cells that can differentiate into bile duct cells or hepatocytes, whereas myofibroblasts are the principal source of collagen production in fibrosis. The aims of this study were to determine 1) whether BDL induces oval cell proliferation and 2) whether blockade of Kupffer cells affects oval cell proliferation, bile duct proliferation, and myofibroblast transformation in experimental biliary obstruction. Male Sprague-Dawley rats were divided into two groups to receive either a single dose of gadolinium chloride (a selective Kupffer cell blocking agent) or vehicle. One day later, the gadolinium- and vehicle-treated groups were further subdivided to receive either BDL or sham operation. The rats were...
Hepatology, 2015
Iron is implicated in the pathogenesis of liver injury and insulin resistance (IR) and thus phleb... more Iron is implicated in the pathogenesis of liver injury and insulin resistance (IR) and thus phlebotomy has been proposed as a treatment for nonalcoholic fatty liver disease (NAFLD). We performed a prospective 6-month randomized, controlled trial examining the impact of phlebotomy on the background of lifestyle advice in patients with NAFLD. Primary endpoints were hepatic steatosis (HS; quantified by magnetic resonance imaging) and liver injury (determined by alanine aminotransaminase [ALT] and cytokeratin-18 [CK-18]). Secondary endpoints included insulin resistance measured by the insulin sensitivity index (ISI) and homeostasis model of assessment (HOMA), and systemic lipid peroxidation determined by plasma F2-isoprostane levels. A total of 74 subjects were randomized (33 phlebotomy and 41 control). The phlebotomy group underwent a median (range) of 7 (1-19) venesection sessions and had a significantly greater reduction in ferritin levels over 6 months, compared to controls (-148 ± 114 vs. -38 ± 89 ng/mL; P < 0.001). At 6 months, there was no difference between phlebotomy and control groups in HS (17.7% vs. 15.5%; P = 0.4), serum ALT (36 vs. 46 IU/L; P = 0.4), or CK-18 levels (175 vs. 196 U/L; P = 0.9). Similarly, there was no difference in end-of-study ISI (2.5 vs. 2.7; P = 0.9), HOMA (3.2 vs. 3.2; P = 0.6), or F2-isoprostane levels (1,332 vs. 1,190 pmmol/L; P = 0.6) between phlebotomy and control groups. No differences in any endpoint were noted in patients with hyperferritinemia at baseline. Among patients undergoing phlebotomy, there was no correlation between number of phlebotomy sessions and change in HS, liver injury, or IR from baseline to end of study. Reduction in ferritin by phlebotomy does not improve liver enzymes, hepatic fat, or IR in subjects with NAFLD. (Hepatology 2014).
Stem Cells and Development, 2010
Non-tumorous liver tissue removed during surgery to resect hepatocellular carcinoma (HCC) is pote... more Non-tumorous liver tissue removed during surgery to resect hepatocellular carcinoma (HCC) is potentially a useful source of material from which cells, particularly liver progenitor/stem cells (LPCs), can be isolated to establish cell lines. The purpose of this study was to evaluate the applicability of the "plate-and-wait" method to derive LPCs from resections to remove HCC. Three independent non-tumorous liver samples from HCC resection and 3 samples from liver donors were used for LPC isolation. Staining for LPC markers, OV6, CK19, and EpCAM, in the above liver samples demonstrated staining in only 2 of the non-tumorous samples. We isolated 2 human liver epithelial cell lines (HLECs) from these 2 samples. These HLECs were positive for general stem cell markers CD133, EpCAM, and Oct4. They expressed the liver progenitor cell markers OV6, CK14, and M2PK but not CK19. They also expressed the hepatocellular markers albumin, CK8, CK18, HNF4-α, and the drug-metabolizing gene CYP3A4. These cells accumulated glycogen, indocyanine green, and synthesized urea. They produced colonies in soft agar that showed anchorage-independent growth and their tumorigenic status was confi rmed when they produced tumors following transfer to athymic nude mice. In contrast, the third nontumorous tissue and 3 normal liver samples did not produce cell lines. This study establishes a correlation between the presence of LPCs in the source liver tissue and the ability to derive cell lines from these tissues. The phenotypic similarities between the LPCs and the HLECs suggest that a precursor-product relationship may exist between the 2 cell types.
Hepatology, 2005
Inflammation influences iron balance in the whole organism. A common clinical manifestation of th... more Inflammation influences iron balance in the whole organism. A common clinical manifestation of these changes is anemia of chronic disease (ACD; also called anemia of inflammation). Inflammation reduces duodenal iron absorption and increases macrophage iron retention, resulting in low serum iron concentrations (hyposideremia). Despite the protection hyposideremia provides against proliferating microorganisms, this "iron withholding" reduces the iron available to maturing red blood cells and eventually contributes to the development of anemia. Hepcidin antimicrobial peptide (Hamp) is a hepatic defensin-like peptide hormone that inhibits duodenal iron absorption and macrophage iron release. Hamp is part of the type II acute phase response and is thought to have a crucial regulatory role in sequestering iron in the context of ACD. Mice with deficiencies in the hemochromatosis gene product, Hfe, mounted a general inflammatory response after injection of lipopolysaccharide but lacked appropriate Hamp expression and did not develop hyposideremia. These data suggest a previously unidentified role for Hfe in innate immunity and ACD.
Hepatology, 2008
Lymphotoxin-beta (LT) is a proinflammatory cytokine and a member of the tumor necrosis factor (T... more Lymphotoxin-beta (LT) is a proinflammatory cytokine and a member of the tumor necrosis factor (TNF) superfamily known for its role in mediating lymph node development and homeostasis. Our recent studies suggest a role for LT in mediating the pathogenesis of human chronic liver disease. We hypothesize that LT coordinates the wound healing response in liver injury via direct effects on hepatic stellate cells. This study used the choline-deficient, ethionine-supplemented (CDE) dietary model of chronic liver injury, which induces inflammation, liver progenitor cell proliferation, and portal fibrosis, to assess (1) the cellular expression of LT, and (2) the role of LT receptor (LTR) in mediating wound healing, in LTR ؊/؊ versus wild-type mice. In addition, primary isolates of hepatic stellate cells were treated with LTR-ligands LT and LT-related inducible ligand competing for glycoprotein D binding to herpesvirus entry mediator on T cells (LIGHT), and mediators of hepatic stellate cell function and fibrogenesis were assessed. LT was localized to progenitor cells immediately adjacent to activated hepatic stellate cells in the periportal region of the liver in wild-type mice fed the CDE diet. LTR ؊/؊ mice fed the CDE diet showed significantly reduced fibrosis and a dysregulated immune response. LTR was demonstrated on isolated hepatic stellate cells, which when stimulated by LT and LIGHT, activated the nuclear factor kappa B (NF-B) signaling pathway. Neither LT nor LIGHT had any effect on alpha-smooth muscle actin, tissue inhibitor of metalloproteinase 1, transforming growth factor beta, or procollagen ␣ 1 (I) expression; however, leukocyte recruitmentassociated factors intercellular adhesion molecule 1 and regulated upon activation T cells expressed and secreted (RANTES) were markedly up-regulated. RANTES caused the chemotaxis of a liver progenitor cell line expressing CCR5. Conclusion: This study suggests that LTR on hepatic stellate cells may be involved in paracrine signaling with nearby LT-expressing liver progenitor cells mediating recruitment of progenitor cells, hepatic stellate cells, and leukocytes required for wound healing and regeneration during chronic liver injury. (HEPATOLOGY 2009;49:227-239.
European Journal of Cardiovascular Prevention & Rehabilitation, 2002
Background Increased iron stores and haemochromatosis gene mutations may be risk factors for coro... more Background Increased iron stores and haemochromatosis gene mutations may be risk factors for coronary heart disease. The aims of this study were to determine in a stable community population whether increased iron stores or haemochromatosis gene mutations were risk factors for coronary heart disease. Design Cross-sectional and prospective cohort studies. Methods We evaluated 1185 men and 1141 women aged 20-79 years of predominantly Anglo-Celtic descent from the 1994-95 assessment of the Busselton population in Western Australia. Subjects underwent haemochromatosis genotyping, serum iron studies, clinical, biochemical and ECG evaluation for coronary heart disease and associated risk factors. Hospital admissions or death from cardiovascular disease were determined by linkage with the Western Australian morbidity and mortality database. The study design was cross-sectional for the 1994-95 cohort comparing coronary heart disease cases with unaffected subjects and unaffected subjects were followed prospectively until December 1998. Results Cross-sectional and prospective cohort analyses demonstrated that elevated serum iron parameters or possession of either the C282Y or H63D mutations in the HFE gene were not predictive of increased risk for coronary heart disease in men or women. Conclusions Increased iron stores or haemochromatosis gene mutations are not significant risk factors for coronary heart disease.
Clinical Gastroenterology and Hepatology, 2014
Author contributions: EJM: study concept, statistical analysis and interpretation of data, drafti... more Author contributions: EJM: study concept, statistical analysis and interpretation of data, drafting of the manuscript and critical revision; ER: study concept, acquisition of data, interpretation of data, drafting of the manuscript and critical revision; JPB: acquisition of data, critical revision of manuscript; DT study concept, interpretation of data, critical revision of manuscript; JKO: study concept and oversight, interpretation of data, drafting of the manuscript and critical revision. Writing Assistance: NA Disclosures: No potential conflicts of interest to disclose by any author.
Carcinogenesis, 2005
Multifaceted evidence links the development of liver tumours to the activation and proliferation ... more Multifaceted evidence links the development of liver tumours to the activation and proliferation of adult liver progenitor (oval) cells during the early stages of chronic liver injury. The aim of this study was to examine the role of the peroxisome proliferator activated receptors (PPARs): PPARa, d and g, in mediating the behaviour of liver progenitor cells during pre-neoplastic disease and to investigate their potential as therapeutic targets for the treatment of chronic liver injury. We observed increased liver expression of PPARa and g in concert with expanding oval cell numbers during the first 21 days following commencement of the choline deficient, ethionine supplemented (CDE) dietary model of carcinogenic liver injury in mice. Both primary and immortalized liver progenitor cells were found to express PPARa, d and g, but not g2, the alternate splice form of PPARg. WY14643 (PPARa agonist), GW501516 (PPARd agonist) and ciglitazone (PPARg agonist) were tested for their ability to modulate the behaviour of p53-immortalized liver (PIL) progenitor cell lines in vitro. Both PPARd and g agonists induced dose-dependent growth inhibition and apoptosis of PIL cells. In contrast, the PPARa agonist had no effect on PIL cell growth. None of the drugs affected the maturation of PIL cells along either the hepatocytic or biliary lineages, as judged by their patterns of hepatic gene expression prior to and following treatment. Administration of the PPARg agonist ciglitazone to mice fed with the CDE diet for 14 days resulted in a significantly diminished oval cell response and decreased fibrosis compared with those receiving placebo. In contrast, GW501516 did not affect oval cell numbers or liver fibrosis, but inhibited CDE-induced hepatic steatosis. In summary, PPARg agonists reduce oval cell proliferation and fibrosis during chronic liver injury and may be useful in the prevention of hepatocellular carcinoma.
BMC Medical Genetics, 2008
Background: We report our experience of selecting tag SNPs in 35 genes involved in iron metabolis... more Background: We report our experience of selecting tag SNPs in 35 genes involved in iron metabolism in a cohort study seeking to discover genetic modifiers of hereditary hemochromatosis. Methods: We combined our own and publicly available resequencing data with HapMap to maximise our coverage to select 384 SNPs in candidate genes suitable for typing on the Illumina platform. Results: Validation/design scores above 0.6 were not strongly correlated with SNP performance as estimated by Gentrain score. We contrasted results from two tag SNP selection algorithms, LDselect and Tagger. Varying r 2 from 0.5 to 1.0 produced a near linear correlation with the number of tag SNPs required. We examined the pattern of linkage disequilibrium of three levels of resequencing coverage for the transferrin gene and found HapMap phase 1 tag SNPs capture 45% of the ≥ 3% MAF SNPs found in SeattleSNPs where there is nearly complete resequencing. Resequencing can reveal adjacent SNPs (within 60 bp) which may affect assay performance. We report the number of SNPs present within the region of six of our larger candidate genes, for different versions of stock genotyping assays. Conclusion: A candidate gene approach should seek to maximise coverage, and this can be improved by adding to HapMap data any available sequencing data. Tag SNP software must be fast and flexible to data changes, since tag SNP selection involves iteration as investigators seek to satisfy the competing demands of coverage within and between populations, and typability on the technology platform chosen.