Homeostasis of iron and hepcidin in erythropoietic protoporphyria.

BACKGROUND: Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are genetic abnormalities of heme synthesis that result in excess production of protoporphyrin and that manifest as severe photosensitivity. These disorders are often associated with iron deficiency anaemia (IDA). Our aim was to determine whether hepcidin is increased in EPP/XLP patients, resulting in decreased enteral iron absorption and IDA. MATERIAL AND METHODS: Eight subjects with EPP, one with XLP and nine controls had baseline blood and urine samples collected, and thereafter were given oral ferrous sulphate (660 mg). Post-iron blood and urine samples were collected at 2, 4, 6 and 8 h. Blood counts, serum cytokines, ferritin and iron studies were analysed at baseline. Serum iron studies, serum and urine hepcidin, and erythropoietin (Epo) were analysed at baseline and subsequent time points. RESULTS: At baseline, EPP-XLP subjects had lower mean blood haemoglobin (13·9/15·3 g/dL) and serum ferritin (31·6/115 ng/mL) than controls. Serum iron levels increased markedly in both cohorts. Mean serum and urine hepcidin levels were significantly lower in the EPP-XLP group at 4 and 8 h post-iron (serum - 4 h, 3·79/26·6, 8 h, 5·79/34·6 nM; urine - 4 h, 0·85/2·50, 8 h, 1·44/6·63 nM/mM creatinine). Serum cytokines and Epo were normal and not different between groups. CONCLUSIONS: We conclude that serum and urine hepcidin are not inappropriately increased in EPP/XLP subjects at baseline and do not increase over time as serum iron increases after oral ferrous sulphate. Levels of serum cytokines and Epo are normal in EPP/XLP. The molecular basis for the iron-deficient phenotype in EPP/XLP remains unknown.

Circadian rhythms in acute intermittent porphyria--a pilot study.

BACKGROUND: Acute intermittent porphyria (AIP) is an inherited disorder of haem synthesis wherein a partial deficiency of porphobilinogen (PBG) deaminase (PBGD) with other factors may give rise to biochemical and clinical manifestations of disease. The biochemical hallmarks of active AIP are relative hepatic haem deficiency and uncontrolled up-regulation of hepatic 5-aminolevulinic acid (ALA) synthase-1 (ALAS1) with over-production of ALA and PBG. The treatment of choice is intravenous haem, which restores the deficient regulatory haem pool of the liver and represses ALAS1. Recently, haem has been shown to influence circadian rhythms by controlling their negative feedback loops. We evaluated whether subjects with AIP exhibited an altered circadian profile. MATERIALS AND METHODS: Over a 21-h period, we measured levels of serum cortisol, melatonin, ALA, PBG and mRNA levels (in peripheral blood mononuclear cells) of selected clock-controlled genes and genes involved in haem synthesis in 10 Caucasian (European-American) women who were either postmenopausal or had been receiving female hormone therapy, six of whom have AIP and four do not and are considered controls. RESULTS: Four AIP subjects with biochemical activity exhibited higher levels of PBG and lower levels and dampened oscillation of serum cortisol, and a trend for lower levels of serum melatonin, than controls or AIP subjects without biochemical activity. Levels of clock-controlled gene mRNAs showed significant increases over baseline in all subjects at 5 a.m. and 11 p.m., whereas mRNA levels of ALAS1, ALAS2 and PBGD were increased only at 11 p.m. in subjects with active AIP. CONCLUSIONS: This pilot study provides evidence for disturbances of circadian markers in women with active AIP that may trigger or sustain some common clinical features of AIP.

Discovery of putative pancreatic cancer biomarkers using subcellular proteomics.

Pancreatic cancer (PC) is a highly aggressive disease that frequently remains undetected until it has progressed to an advanced, systemic stage. Successful treatment of PC is hindered by the lack of early detection. The application of proteomic analysis to PC combined with subcellular fractionation has introduced new possibilities in the field of biomarker discovery. We utilized matched pairs of pancreas tumor and non-tumor pancreas from patients undergoing tumor resection. The tissues were treated to obtain cellular protein fractions corresponding to cytosol, membrane, nucleus and cytoskeleton. The fractions were then separated by molecular weight and digested with trypsin, followed by liquid chromatography and tandem mass spectrometry. The spectra obtained were searched using Sequest engine and combined into a single analysis file to obtain a semi-quantitative number, spectral count, using Scaffold software. We identified 2393 unique proteins in non-tumor and cancer pancreas. Utilizing PLGEM statistical analysis we determined 104 proteins were significantly changed in cancer. From these, we further validated four secreted proteins that are up-regulated in cancer and have potential for development as minimally-invasive diagnostic markers. We conclude that subcellular fractionation followed by gel electrophoresis and tandem mass spectrometry is a powerful strategy for identification of differentially expressed proteins in pancreatic cancer.