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1.  Iron Refractory Iron Deficiency Anemia: Presentation With Hyperferritinemia and Response to Oral Iron Therapy 
Pediatrics  2013;131(2):e620-e625.
Iron-refractory iron-deficiency anemia (IRIDA) is an autosomal recessive disorder caused by mutations in TMPRSS6. Patients have hypochromic microcytic anemia refractory to oral iron and are only partially responsive to parenteral iron administration. We report a French-Canadian kindred in which 2 siblings presented in early childhood with severe microcytic anemia, hypoferremia, and hyperferritinemia. Both children have been successfully treated solely with low-dose oral iron since diagnosis. Clinical and biological presentation did not fit any previously described genetic iron-deficiency anemia. Whole exome sequencing identified in both patients compound heterozygous mutations of TMPRSS6 leading to p.G442R and p.E522K, 2 mutations previously reported to cause classic IRIDA, and no additional mutations in known iron-regulatory genes. Thus, the phenotype associated with the unique combination of mutations uncovered in both patients expands the spectrum of disease associated with TMPRSS6 mutations to include iron deficiency anemia that is accompanied by hyperferritinemia at initial presentation and is responsive to continued oral iron therapy. Our results have implications for genetic testing in early childhood iron deficiency anemia. Importantly, they emphasize that whole exome sequencing can be used as a diagnostic tool and greatly facilitate the elucidation of the genetic basis of unusual clinical presentations, including hypomorphic mutations or compound heterozygosity leading to different phenotypes in known Mendelian diseases.
PMCID: PMC3675830  PMID: 23319530
iron; TMPRSS6; hypomorphic mutations; hepcidin; whole exome sequencing; anemia
2.  Intestinal Ferroportin Expression in Pediatric Crohn’s Disease 
Inflammatory bowel diseases  2011;17(2):524-531.
Anemia is a frequent complication of Crohn’s disease (CD). The intestinal iron exporter ferroportin (FPN) is involved in both iron deficiency anemia and the anemia of chronic disease. To examine its role in CD, intestinal FPN expression was studied in subjects with and without CD.
Duodenal mucosal biopsies from 29 pediatric subjects with CD (n = 19) and without CD (n = 10) were obtained. FPN protein was measured using Western blot analysis and mRNA was assessed using quantitative real-time polymerase chain reaction (PCR).
Intestinal FPN protein was higher in anemic CD subjects than in nonanemic CD subjects (P = 0.01), while FPN mRNA levels were not different (P = 0.66). In nonanemic CD subjects, erythrocyte sedimentation rate (ESR) (P = 0.04), C-reactive protein (CRP) (P = 0.03), and interleukin-6 (IL-6) (P = 0.01) levels were elevated compared to controls. Nonanemic CD subjects had a lower median FPN protein than nonanemic controls, although it did not reach statistical significance (P = 0.07). Median FPN mRNA was similar between groups (P = 0.71). Although no correlation between FPN protein and IL-6 was noted, there was a strong negative correlation between serum iron and IL-6, both in subjects with CD (r = −0.88, P < 0.0001) and those without anemia (r = −0.58, P = 0.02).
Intestinal FPN protein is upregulated in anemic CD subjects, suggesting that iron deficiency or anemia is the driving force regulating FPN levels. A transporter distinct from FPN appears to be involved in the hypoferremia associated with the inflammatory process of CD.
PMCID: PMC3733087  PMID: 20564534
Crohn’s disease; anemia; ferroportin; iron
Hypoferremia is a marker of disease severity in cystic fibrosis (CF). The effect of systemic antibiotics on iron homeostasis during CF pulmonary exacerbation (CFPE) is unknown. Our central hypotheses were that, by the completion of treatment, serum iron would increase, serum concentrations of interleukin-6 (IL-6) and hepcidin-25, two mediators of hypoferremia, would decrease, and sputum iron would decrease. Methods: Blood and sputum samples were collected from 12 subjects with moderate-to-severe CF (median percent-predicted forced expiratory volume in one second (FEV1%) = 29%; median weight = 56 kg) within 24 hours of starting and completing a course of systemic antibiotics. Results: After treatment, subjects showed median FEV1% and body weight improvements of 4.5% and 2.0 kg, respectively (p <0.05). Median serum iron rose by 2.4 μmol/l (p <0.05), but 75% of patients remained hypoferremic. Median serum IL-6 and hepcidin-25 levels fell by 12.1 pg/ml and 37.5 ng/ml, respectively (p <0.05). Median serum erythropoietin (EPO) and hemoglobin levels were unaffected by treatment. We observed a trend toward lower sputum iron content after treatment. Conclusions: Hypoferremia is a salient characteristic of CFPE that improves with waning inflammation. Despite antibiotic treatment, many patients remain hypoferremic and anemic due to ineffective erythropoiesis.
PMCID: PMC3419499  PMID: 22883617
iron; hepcidin; cystic fibrosis; interleukin-6; exacerbation
4.  Subcutaneous Adipose Tissue from Obese and Lean Adults Does Not Release Hepcidin In Vivo 
TheScientificWorldJournal  2011;11:2197-2206.
Hepcidin is the main regulator of systemic iron homeostasis and is primarily produced by the liver but is also expressed, at the mRNA-level, in periphery tissues including the subcutaneous and visceral adipose tissue. Obesity is associated with elevated hepcidin concentrations and iron depletion suggesting that the exaggerated fat mass in obesity could contribute significantly to circulating hepcidin levels consequently altering iron homeostasis. The objective of this study was to determine if abdominal subcutaneous adipose tissue (AbScAT) releases hepcidin in vivo and if release is modified by obesity. Arterio-venous differences in concentrations of hepcidin were measured across AbScAT in 9 obese and 9 lean adults. Overall (n = 18), mean plasma hepcidin concentrations were significantly higher in arterialized compared to AbScAT venous samples [mean difference (arterialized-AbScAT venous plasma hepcidin) = 4.9 ± 9.6 ng/mL, P = 0.04]. Net regional release was not calculated because mean venous plasma hepcidin concentrations were lower than mean arterialized concentrations indicating no net release. Significant correlations between AbScAT venous and arterialized plasma hepcidin concentrations with anthropometric variables were not observed. Findings from this vein drainage study suggest there is no net release of hepcidin from the AbScAT depot and thereby no ability to signal systemically, even in obesity.
PMCID: PMC3217603  PMID: 22125467
hepcidin; obesity; adipose tissue; in vivo secretion; iron homeostasis
5.  Urine hepcidin has additive value in ruling out cardiopulmonary bypass-associated acute kidney injury: an observational cohort study 
Critical Care  2011;15(4):R186.
Conventional markers of acute kidney injury (AKI) lack diagnostic accuracy and are expressed only late after cardiac surgery with cardiopulmonary bypass (CPB). Recently, interest has focused on hepcidin, a regulator of iron homeostasis, as a unique renal biomarker.
We studied 100 adult patients in the control arm of a randomized, controlled trial who were identified as being at increased risk of AKI after cardiac surgery with CPB. AKI was defined according to the Risk, Injury, Failure, Loss, End-stage renal disease classification of AKI classification stage. Samples of plasma and urine were obtained simultaneously (1) before CPB (2) six hours after the start of CPB and (3) twenty-four hours after CPB. Plasma and urine hepcidin 25-isoforms were quantified by competitive enzyme-linked immunoassay.
In AKI-free patients (N = 91), urine hepcidin concentrations had largely increased at six and twenty-four hours after CPB, and they were three to seven times higher compared to patients with subsequent AKI (N = 9) in whom postoperative urine hepcidin remained at preoperative levels (P = 0.004, P = 0.002). Furthermore, higher urine hepcidin and, even more so, urine hepcidin adjusted to urine creatinine at six hours after CPB discriminated patients who did not develop AKI (area under the curve (AUC) receiver operating characteristic curve 0.80 [95% confidence interval (95% CI) 0.71 to 0.87] and 0.88 [95% CI 0.78 to 0.97]) or did not need renal replacement therapy initiation (AUC 0.81 [95% CI 0.72 to 0.88] 0.88 [95% CI 0.70 to 0.99]) from those who did. At six hours, urine hepcidin adjusted to urine creatinine was an independent predictor of ruling out AKI (P = 0.011). Plasma hepcidin did not predict no development of AKI. The study findings remained essentially unchanged after excluding patients with preoperative chronic kidney disease.
Our findings suggest that urine hepcidin is an early predictive biomarker of ruling out AKI after CPB, thereby contributing to early patient risk stratification.
PMCID: PMC3387629  PMID: 21816077
6.  Highly Elevated Serum Hepcidin in Patients with Acute Myeloid Leukemia prior to and after Allogeneic Hematopoietic Cell Transplantation: Does This Protect from Excessive Parenchymal Iron Loading? 
Advances in Hematology  2011;2011:491058.
Hepcidin is upregulated by inflammation and iron. Inherited (HFE genotype) and treatment-related factors (blood units (BU), Iron overload) affecting hepcidin (measured by C-ELISA) were studied in 42 consecutive patients with AML prior to and after allogeneic hematopoietic cell transplantation (HCT). Results. Elevated serum ferritin pre- and post-HCT was present in all patients. Median hepcidin pre- and post-HCT of 358 and 398 ng/mL, respectively, were elevated compared to controls (median 52 ng/mL) (P < .0001). Liver and renal function, prior chemotherapies, and conditioning had no impact on hepcidin. Despite higher total BU after HCT compared to pretransplantation (P < .0005), pre- and posttransplant ferritin and hepcidin were similar. BU influenced ferritin (P = .001) and hepcidin (P = .001). No correlation of pre- or posttransplant hepcidin with pretransplant ferritin was found. HFE genotype did not influence hepcidin. Conclusions. Hepcidin is elevated in AML patients pre- and post-HCT due to transfusional iron-loading suggesting that hepcidin synthesis remains intact despite chemotherapy and HCT.
PMCID: PMC3112503  PMID: 21687645
7.  Streptococcus iniae Phosphoglucomutase Is a Virulence Factor and a Target for Vaccine Development  
Infection and Immunity  2005;73(10):6935-6944.
Streptococcus iniae represents a major health and economic problem in fish species worldwide. Random Tn917 mutagenesis and high-throughput screening in a hybrid striped bass (HSB) model of meningoencephalitis identified attenuated S. iniae mutants. The Tn917 insertion in one mutant disrupted an S. iniae homologue of a phosphoglucomutase (pgm) gene. Electron microscopy revealed a decrease in capsule thickness and cell wall rigidity, with ΔPGM mutant cells reaching sizes ∼3-fold larger than those of the wild type (WT). The ΔPGM mutant was cleared more rapidly in HSB blood and was more sensitive to killing by cationic antimicrobial peptides including moronecidin from HSB. In vivo, the ΔPGM mutant was severely attenuated in HSB, as intraperitoneal challenge with 1,000 times the WT lethal dose produced only 2.5% mortality. Reintroduction of an intact copy of the S. iniae pgm gene on a plasmid vector restored antimicrobial peptide resistance and virulence to the ΔPGM mutant. In analysis of the aborted infectious process, we found that ΔPGM mutant organisms initially disseminated to the blood, brain, and spleen but were eliminated by 24 h without end organ damage. Ninety to 100% of fish injected with the ΔPGM mutant and later challenged with a lethal dose of WT S. iniae survived. We conclude that the pgm gene is required for virulence in S. iniae, playing a role in normal cell wall morphology, surface capsule expression, and resistance to innate immune clearance mechanisms. An S. iniae ΔPGM mutant is able to stimulate a protective immune response and may have value as a live attenuated vaccine for aquaculture.
PMCID: PMC1230984  PMID: 16177373

Results 1-7 (7)