Iron overload patients with unknown etiology from national survey in Japan.

Transfusion is believed to be the main cause of iron overload in Japan. A nationwide survey on post-transfusional iron overload subsequently led to the establishment of guidelines for iron chelation therapy in this country. To date, however, detailed clinical information on the entire iron overload population in Japan has not been fully investigated. In the present study, we obtained and studied detailed clinical information on the iron overload patient population in Japan. Of 1109 iron overload cases, 93.1% were considered to have occurred post-transfusion. There were, however, 76 cases of iron overload of unknown origin, which suggest that many clinicians in Japan may encounter some difficulty in correctly diagnosing and treating iron overload. Further clinical data were obtained for 32 cases of iron overload of unknown origin; median of serum ferritin was 1860.5 ng/mL. As occurs in post-transfusional iron overload, liver dysfunction was found to be as high as 95.7% when serum ferritin levels exceeded 1000 ng/mL in these patients. Gene mutation analysis of the iron metabolism-related genes in 27 cases of iron overload with unknown etiology revealed mutations in the gene coding hemojuvelin, transferrin receptor 2, and ferroportin; this indicates that although rare, hereditary hemochromatosis does occur in Japan.

Iron-induced epigenetic abnormalities of mouse bone marrow through aberrant activation of aconitase and isocitrate dehydrogenase.

Iron overload remains a concern in myelodysplastic syndrome (MDS) patients. Iron chelation therapy (ICT) thus plays an integral role in the management of these patients. Moreover, ICT has been shown to prolong leukemia-free survival in MDS patients; however, the mechanisms responsible for this effect are unclear. Iron is a key molecule for regulating cytosolic aconitase 1 (ACO1). Additionally, the mutation of isocitrate dehydrogenase (IDH), the enzyme downstream of ACO1 in the TCA cycle, is associated with epigenetic abnormalities secondary to 2-hydroxyglutarate (2-HG) and DNA methylation. However, epigenetic abnormalities observed in many MDS patients occur without IDH mutation. We hypothesized that iron itself activates the ACO1-IDH pathway, which may increase 2-HG and DNA methylation, and eventually contribute to leukemogenesis without IDH mutation. Using whole RNA sequencing of bone marrow cells in iron-overloaded mice, we observed that the enzymes, phosphoglucomutase 1, glycogen debranching enzyme, and isocitrate dehydrogenase 1 (Idh1), which are involved in glycogen and glucose metabolism, were increased. Digital PCR further showed that Idh1 and Aco1, enzymes involved in the TCA cycle, were also elevated. Additionally, enzymatic activities of TCA cycle and methylated DNA were increased. Iron chelation reversed these phenomena. In conclusion, iron activation of glucose metabolism causes an increase of 2-HG and DNA methylation.

[Evaluation of Basic Performance of "Point Strip ferritin-3000" for Simple and Rapid Quantification of Serum Ferritin].

Serum ferritin is an excellent marker for total iron content in the body and is essential for the diagnosis of iron deficiency or iron overload. Recently, a simple and rapid method, which utilizes immunochromatography for the quantification of serum ferritin, was developed. However, the range of measurement in previous reagents was limited (10-500 ng/mL). This range is rather narrow and is not fully helpful for the diagnosis of iron overload which sometimes occurs as a result of prolonged transfusions, or for monitoring iron contents during iron chelation therapy against iron overload. In the present study we evaluated the basic performance of the newly developed "Point Strip ferritin-3000", which can measure serum ferritin in the range of 300-3,000 ng/mL. Coefficient of variation (CV) s of within and inter-day assays were in the ranges of 7.3-11.1% and 2.1-5.2%, respectively. Using 87 serum samples obtained from the patients with written informed consents, the correlation coefficient was calculated to be 0.93 compared to the control method. In addition, the quantification of serum ferritin by "Point Strip ferritin-3000" was not influenced by bilirubin, hemoglobin, chyle, rheumatoid factor, or ascorbic acid. From our data, "Point Strip ferritin-3000" is reliable reagent in the range of 300-3,000 ng/mL, and is therefore considered to be useful for the diagnosis of iron overload, as well as for monitoring iron contents during iron chelation therapy. In addition, this quantification method can be easily performed using a small desktop equipment without any special technique, making this system applicable for epidemiological surveys and clinical studies.