Splenectomy prevents brain orexin, ghrelin, or oxytocin but not GLP-1-induced improvement of intestinal barrier function in rats.

BACKGROUND: Accumulating evidence has suggested that neuropeptides such as orexin, ghrelin, or oxytocin act centrally in the brain to regulate intestinal barrier function through the vagus nerve. It has been reported that the vagal cholinergic anti-inflammatory pathway was blocked by splenectomy. In the present study, we therefore examined the effect of splenectomy on neuropeptides-induced improvement of increased intestinal permeability. METHODS: Colonic permeability was determined in vivo by quantifying the absorbed Evans blue in colonic tissue for 15 min spectrophotometrically in rats. RESULTS: Splenectomy increased colonic permeability. The increased permeability by splenectomy was significantly blocked by vagal activation induced by carbachol or 2-deoxy-d-glucose which was prevented by atropine, suggesting vagal activation could prevent colonic hyperpermeability in splenectomized rats. In the splenectomized rats, intracisternal injection of orexin, ghrelin, oxytocin, or butyrate failed to inhibit increased colonic permeability while intracisternal glucagon-like peptide-1 (GLP-1) analogue, liraglutide, potently blocked the increased colonic permeability in a dose-dependent manner. The liraglutide-induced improvement of increased colonic permeability was blocked by atropine in splenectomized rats. Intracisternal injection of GLP-1 receptor antagonist attenuated 2-deoxy-d-glucose-induced improvement of colonic hyperpermeability in splenectomized rats. CONCLUSION: The present results suggested that the spleen is important in the improvement of intestinal barrier function by brain orexin, ghrelin or oxytocin, and butyrate. On the other hand, GLP-1 acts centrally in the brain to improve colonic hyperpermeability in a spleen-independent manner. All these results suggest that dual mechanisms (spleen dependent or independent) may exist for the brain-gut regulation in intestinal barrier function.

Monitoring mutant KRAS in plasma cell-free DNA can predict disease progression in a patient with multiple myeloma: A case report.

BACKGROUND AND AIMS: Multiple myeloma (MM), a neoplasm of plasma cells (PCs), is a highly heterogeneous disease with multifocal dissemination throughout the body. Minimal residual disease (MRD) detected using PCs in bone marrow (BM) is important for MM management; however, frequent invasive examinations impose a significant burden on patients. METHODS: Analysis using plasma cell-free DNA (cfDNA) might represent an alternative tool for disease monitoring. In this study, we observed the disease status in a patient with MM by examining the KRAS mutation allele frequency (MAF) in plasma cfDNA using digital PCR. RESULTS: During treatment, the MAF was correlated with serum immunoglobulin A and free light chain-kappa levels. After the second autologous peripheral blood stem cell transplantation, the KRAS MAF became immediately positive after confirming MRD negativity using PCs from BM. Shortly thereafter, the patient experienced clinical relapse primarily involving bone lesions. CONCLUSION: Mutant KRAS monitoring in cfDNA using serial blood collection might reflect the disease status more accurately than invasive BM examinations, especially in patients with MM whose primary lesions have extra-BM locations. It could also help predict treatment responses and outcomes.

Ghrelin prevents lethality in a rat endotoxemic model through central effects on the vagal pathway and adenosine A2B signaling : Brain ghrelin and anti-septic action.

Accumulating evidence suggest that ghrelin plays a role as an antiseptic peptide. The present study aimed to clarify whether the brain may be implicated ghrelin's antiseptic action. We examined the effect of brain ghrelin on survival in a novel endotoxemic model achieved by treating rats with lipopolysaccharide (LPS) and colchicine. The observation of survival stopped three days after chemicals' injection or at death. Intracisternal ghrelin dose-dependently reduced lethality in the endotoxemic model; meanwhile, neither intraperitoneal injection of ghrelin nor intracisternal des-acyl-ghrelin injection affected the mortality rate. The brain ghrelin-induced lethality reduction was significantly blocked by surgical vagotomy. Moreover, intracisternal injection of a ghrelin receptor antagonist blocked the improved survival achieved by intracisternal ghrelin injection or intravenous 2-deoxy-d-glucose administration. Intracisternal injection of an adenosine A2B receptor agonist reduced the lethality and the ghrelin-induced improvement of survival was blocked by adenosine A2B receptor antagonist. I addition, intracisternal ghrelin significantly blocked the colonic hyperpermeability produced by LPS and colchicine. These results suggest that ghrelin acts centrally to reduce endotoxemic lethality. Accordingly, activation of the vagal pathway and adenosine A2B receptors in the brain may be implicated in the ghrelin-induced increased survival. Since the efferent vagus nerve mediates anti-inflammatory mechanisms, we speculate that the vagal cholinergic anti-inflammatory pathway is implicated in the decreased septic lethality caused by brain ghrelin.

Centrally administered GLP-1 analogue improves intestinal barrier function through the brain orexin and the vagal pathway in rats.

Leaky gut, an altered intestinal barrier function, has been described in many diseases such as irritable bowel syndrome (IBS). We have recently demonstrated that orexin in the brain blocked leaky gut in rats, suggesting that the brain plays a role in regulation of intestinal barrier function. In the present study, we tried to clarify whether GLP-1 acts centrally in the brain to regulate intestinal barrier function and its mechanism. Colonic permeability was estimated in vivo by quantifying the absorbed Evans blue in colonic tissue in rats. Intracisternal injection of GLP-1 analogue, liraglutide dose-dependently abolished increased colonic permeability in response to lipopolysaccharide. Either atropine or surgical vagotomy blocked the central GLP-1-induced improvement of colonic hyperpermeability. Intracisternal GLP-1 receptor antagonist, exendin (9-39) prevented the central GLP-1-induced blockade of colonic hyperpermeability. In addition, intracisternal injection of orexin receptor antagonist, SB-334867 blocked the GLP-1-induced improvement of intestinal barrier function. On the other hand, subcutaneous liraglutide also improved leaky gut but larger doses of liraglutide were needed to block it. In addition, neither atropine nor vagotomy blocked subcutaneous liraglutide-induced improvement of leaky gut, suggesting that central or peripheral GLP-1 system works separately to improve leaky gut in a vagal-dependent or independent manner, respectively. These results suggest that GLP-1 acts centrally in the brain to reduce colonic hyperpermeability. Brain orexin signaling and the vagal cholinergic pathway play a vital role in the process. We would therefore suggest that activation of central GLP-1 signaling may be useful for leaky gut-related diseases such as IBS.

[Successful rituximab treatment of TAFRO syndrome refractory to glucocorticoids and tocilizumab].

A 53-year-old man was presented with fever, eyelid edema, and thrombocytopenia. Based on examination outcomes, he was diagnosed with immune thrombocytopenia. He was prescribed prednisolone (PSL) at 0.5 mg/kg/day; subsequently, his platelet count improved and fever improved. PSL dose was tapered and stopped without relapse. However, 1 month later, the patient presented to our hospital with fever, generalized edema, thrombocytopenia, and acute renal failure. Computed tomography revealed multiple lymphadenopathies, hepatomegaly, pleural effusion, and ascites. Bone marrow biopsy indicated reticulin fibrosis, and lymph node biopsy revealed mixed-type Castleman disease. Based on these findings, he was diagnosed with grade 5 TAFRO syndrome (very severe). Steroid pulse therapy and tocilizumab were ineffective in improving his condition. Therefore, rituximab was administered instead of tocilizumab, and his condition eventually improved. The optimal treatment for TAFRO syndrome is yet to be established. If tocilizumab is ineffective as the second-line treatment, then rituximab might be effective.

Late-onset posttransplant Epstein-Barr virusrelated lymphoproliferative disease after cord blood transplantation for chronic active Epstein Barr virus infection: A case report.

INTRODUCTION: Posttransplant lymphoproliferative disease (PTLD) is a critical complication of hematopoietic stem cell transplantation (HSCT). PTLD is classified into early and late-onset PTLDs. In post-HSCT patients, late-onset PTLD is rare, particularly PTLD after HSCT for Epstein-Barr virus (EBV)-related lymphoproliferative disease. Here, we report the case of a patient diagnosed with late-onset EBV-related hemophagocytic lymphohistiocytosis (HLH), that of PTLD, after HSCT for chronic active EBV infection (CAEBV), that of EBV related lymphoproliferative disease, probably because of EBV reactivation. PATIENT CONCERNS AND DIAGNOSIS: A 22-year-old woman with abdominal fullness visited our hospital. Blood examination showed pancytopenia with atypical lymphocytes, liver dysfunction, and elevated lactate dehydrogenase level. In contrast, bone marrow aspiration showed slight hemophagocytosis with increased natural-killer cells (NK cells). As serum antibodies against EBV were atypical, we calculated the EBV-DNA level in peripheral blood and this level was significantly high. EBV was infected with NK cells, and EBV's monoclonality in NK cells was confirmed. Thus, the patient was diagnosed with CAEBV. INTERVENTIONS AND OUTCOMES: The patient received chemotherapy and cord blood cell transplantation (CBT); CAEBV was well controlled. Approximately 6years from CBT for CAEBV, she visited our hospital because of fever. Blood examination revealed pancytopenia with atypical lymphocytes, liver dysfunction, and elevated lactate dehydrogenase level. In contrast, bone marrow aspiration showed hemophagocytosis with increased B and T cell counts without increased NK cell count. Additionally, serum antibody titers against EBV were atypical, and the EBV-DNA level in the peripheral blood was high. EBV was infected with only B cells, and EBV's monoclonality was confirmed. A more detailed analysis indicated that EBV-specific cytotoxic T lymphocytes were inactive. Therefore, she was diagnosed with late-onset EBV-related HLH. She received extensive treatment, but EBV-related HLH did not improve. Finally, she died about 3 weeks after diagnosis. CONCLUSION: PTLD, including HLH, is a life-threatening complication after transplantation, including HSCT. To our knowledge, this is the first case of late-onset EBV-related HLH after CBT for CAEBV. Late-onset PTLD has an indolent clinical course, but our patient's disease course was extremely aggressive. Therefore, late-onset EBV-related PTLD may be life-threatening.

Acquired hemophilia A associated with Epstein-Barr-virus-associated T/natural killer-cell lymphoproliferative disease: A case report.

INTRODUCTION: Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against factor VIII (FVIII). Hematological malignancies, especially lymphoid malignancies, are known to be underlying causes of AHA; however, thus far, there is no report of AHA associated with Epstein-Barr-virus-associated T/natural killer-cell lymphoproliferative disease (EBV-T/NK-LPD). Here, we present a case of AHA that developed during treatment for EBV-T/NK-LPD. HISTORY: A 69-year-old man visited our hospital because of general fatigue. Blood examination showed pancytopenia, and computed tomography revealed whole-body lymphadenopathy, but there were no findings indicating hematological malignancy from bone marrow aspiration and cervical lymph node biopsy. The level of EBV DNA in peripheral blood was extremely high, and he was diagnosed with EBV-T/NK-LPD. EBV-T/NK-LPD improved with prednisolone (PSL) administration. Seventeen months after starting treatment, the patient complained of back and right leg pain. At that time, he had been treated with low-dose PSL, and EBV-T/NK-LPD was well controlled. Imaging revealed hematoma of the right iliopsoas muscle. Prolonged activated partial thromboplastin time (APTT) was the only abnormal finding in a screening coagulation test. FVIII coagulant activity was below detection limit, and FVIII inhibitor level was increased. From these results, he was diagnosed with AHA.A higher dose of PSL was administered, and, after 1 month of treatment, FVIII activity gradually increased, and FVIII inhibitor level became undetectable. APTT also normalized, and complete remission was achieved and maintained for 13 months with low-dose PSL. During treatment, EBV-T/NK-LPD was well controlled. CONCLUSION: It is speculated that proliferating lymphocytes interfere with normal immune functions and that abnormal autoantibodies are produced from those lymphocytes in patients with LPD. Therefore, we speculate that EBV-infected and proliferating monoclonal NK cells might have modulated the immune system and produced autoantibodies against FVIII, thus causing AHA in this patient with EBV-T/NK-LPD.

Long-term phlebotomy successfully alleviated hepatic iron accumulation in a ferroportin disease patient with a mutation in SLC40A1: a case report.

BACKGROUND: Hereditary hemochromatosis is a heterogenous group of inherited iron-overload conditions that is characterized by increased intestinal absorption and deposition in vital organs. Hepcidin is a soluble regulator that acts to attenuate both intestinal iron absorption and iron release from reticuloendothelial macrophages through internalization of ferroportin-1, an iron exporter. Ferroportin disease is hereditary hemochromatosis which is affected by SLC40A1, a gene coding ferroportin-1, and phenotypically classified into two forms (classical and nonclassical). In nonclassical form, ferroportin mutations are responsible for a gain of function with full iron export capability but insensitivity to downregulation by hepcidin. Here, we report a case of nonclassical ferroportin disease. CASE PRESENTATION: A 46-year-old Japanese man showed elevated serum iron (284 µg/dl), ferritin (1722 ng/ml), transferrin saturation ratio (91.3%), and hepcidin-25 level (139.6 ng/ml). Magnetic resonance imaging (MRI) demonstrated a marked reduction in the signal intensity of the liver in T1- and T2-weighted images. The liver histology exhibited a large amount of iron that had accumulated predominantly in hepatocytes. We identified a heterozygous 1520A > G (p.H507R) mutation in the SLC40A1 gene. Phlebotomy (400 ml at a time) was monthly performed for 3 years in this patient. Importantly, the serum hepcidin level (1.0 ng/ml) was normal when the serum ferritin level was normal and hepatic iron accumulation was remarkably reduced after 3 years of phlebotomy. CONCLUSIONS: The present case demonstrated for the first time that there was a correlation between hepatic iron levels as measured by MRI and serum hepcidin levels through long-term phlebotomy in a patient with ferroportin disease with the p.H507R mutation of in SLC40A1.

Type 4B hereditary hemochromatosis due to heterozygous p.D157A mutation in SLC40A1 complicated with hypopituitarism.

Hemochromatosis is a clinical syndrome characterized by iron overload in various organs. We present here a case of type 4 hereditary hemochromatosis due to heterozygous mutation in SLC40A1 gene (p.D157A). SLC40A1 encodes ferroportin, a macromolecule only known as iron exporter from mammalian cells. He first presented symptoms correlated with hypopituitarism. Furthermore, marked hyperferritinemia and high transferrin saturation were revealed in combination with the findings of iron overload in the liver, spleen and pituitary gland by computed tomography and magnetic resonance imaging. Liver biopsy revealed iron deposition in both hepatocytes and Kupffer cells. SLC40A1 mutations are considered to cause wide heterogeneity by various ferroportin mutations. Thus, clinicopathological examinations seem to be very important for diagnosing phenotype of type 4 hemochromatosis in addition to the gene analysis. We diagnosed him as type 4B hereditary hemochromatosis (ferroportin-associated hemochromatosis) by the findings of high transferrin saturation and iron deposition in hepatocytes, and then started iron chelating treatment. We should suspect the possibility of hereditary hemochromatosis even in Japanese with severe iron overload. Although the same mutation in SLC40A1 gene (p.D157A) had been reported to cause "loss of function" phenotype, we considered that the mutation of our case caused "gain of function" phenotype.

Centrally administered orexin prevents lipopolysaccharide and colchicine induced lethality via the vagal cholinergic pathway in a sepsis model in rats.

Orexins are neuropeptides implicated in several physiological functions. Accumulating findings suggest a relationship between orexin and sepsis. A recent study demonstrated that orexin acts centrally to improve conditions in sepsis. The present study aims to clarify the precise mechanisms by which central orexin could induce a protective action against septic conditions. We established a new septic model by treating rats with lipopolysaccharide (LPS) and colchicine and used this to examine the effect of brain orexin on survival. Observation of survival was stopped three days after the chemicals injection or at death. We established a lethal model (rats died within 24 h) by injecting subcutaneously a combination of 1 mg/kg LPS and 1 mg/kg colchicine. A Toll-like receptor 4 (TLR4) inhibitor completely blocked lethality, suggesting a vital role of LPS-TLR4 signaling in the process. Intracisternal orexin-A dose-dependently reduced lethality in the sepsis model while neither intracisternal orexin-B nor intraperitoneal orexin-A changed the mortality rate. Vagal stimulation with carbachol or 2-deoxy-D-glucose improved survival and atropine potently blocked the protection by carbachol or 2-deoxy-D-glucose. The orexin-A-induced reduction of lethality was significantly blocked by atropine or surgical vagotomy. Intracisternal injection of an OX1 receptor antagonist blocked the improvement of survival by intracisternal injection of orexin-A, carbachol, or 2-deoxy-D-glucose. These results suggest that orexin acts centrally to reduce the lethality in our septic model treated (LPS and colchicine). Activation of the vagal cholinergic pathway may mediate the action of orexin, and the OX1 receptor in the brain might play a role in the process. Since the efferent vagus nerve mediates anti-inflammatory mechanisms, we speculate that the vagal cholinergic anti-inflammatory pathway is implicated in the mechanisms of septic lethality reduction by brain orexin.

Juvenile Hemochromatosis: A Case Report and Review of the Literature.

Juvenile hemochromatosis (JH), type 2A hemochromatosis, is a rare autosomal recessive disorder of systemic iron overload due to homozygous mutations of HJV (HFE2), which encodes hemojuvelin, an essential regulator of the hepcidin expression, causing liver fibrosis, diabetes, and heart failure before 30 years of age, often with fatal outcomes. We report two Japanese sisters of 37 and 52 years of age, with JH, who showed the same homozygous HJV I281T mutation and hepcidin deficiency and who both responded well to phlebotomy on an outpatient basis. When all reported cases of JH with homozygous HJV mutations in the relevant literature were reviewed, we found-for the first time-that JH developed in females and males at a ratio of 3:2, with no age difference in the two groups. Furthermore, we found that the age of onset of JH may depend on the types of HJV mutations. In comparison to patients with the most common G320V/G320V mutation, JH developed earlier in patients with L101P/L101P or R385X/R385X mutations and later in patients with I281T/I281T mutations.

Identification of heterozygous p.Y150C and p.V274M mutations in the HJV gene in a Japanese patient with a mild phenotype of juvenile hemochromatosis: A case report.

Juvenile hemochromatosis (JH) is known as a progressive iron-storage disease, and causes severe organ impairments, including cardiomyopathy and liver cirrhosis. However, JH is a rare genetic disorder, and information for genetic mutations and phenotypes is limited. Here, we report a case of JH with heterozygous p.Y150C and p.V274M mutations in the HJV gene. A 39-year-old Japanese man was referred to Kurume University Hospital, Kurume, Japan, for fatigue and liver injury, which first appeared at the age of 25 years. There was no history of alcohol abuse and medication, and viral hepatitis, autoimmune liver diseases, and Wilson's disease were absent. However, transferrin saturation, serum ferritin, and fasting serum hepcidin levels were 98.4%, 6421 ng/mL, and 7.4 ng/mL, respectively. Furthermore, a marked reduction in signal intensity of the liver in T1/T2-weighted magnetic resonance images was seen and the R2* maps showed hepatic iron overload. Family history of hemochromatosis and severe organ impairment, such as cardiac dysfunction and diabetes mellitus, were negative. In addition, the HFE and HAMP genes did not show any mutation. However, we identified novel heterozygous p.Y150C and p.V274M mutations in the HJV gene in the patient. The p.Y150C and p.V274M mutations were seen in his mother and father, respectively. After phlebotomy, fatigue disappeared and serum transaminase levels were normalized. Furthermore, R2* maps showed a reduction of hepatic iron concentration. We first demonstrated heterozygous p.Y150C and p.V274M mutations in the HJV gene of patients with a mild JH phenotype. Thus, genetic testing should be considered even in patients with a mild phenotype of hemochromatosis.

Pseudogout Attack after Pegfilgrastim Administration in Anaplastic Large Cell Lymphoma.

A 67-year-old man with relapsed anaplastic large cell lymphoma received salvage chemotherapy, and pegfilgrastim was used to prevent febrile neutropenia. On day 18 of chemotherapy, he developed a pseudogout attack. Although the first symptoms improved, another pseudogout attack occurred when he received the second course of chemotherapy and pegfilgrastim. Filgrastim was then used for the third course of chemotherapy, and a pseudogout attack did not occur. The serum granulocyte-stimulating factor (G-CSF) level was extremely elevated only when pegfilgrastim was used, suggesting a relationship between pseudogout and G-CSF. Pseudogout should be recognized as an adverse effect of pegfilgrastim.

Angioimmunoblastic T-cell lymphoma and hypereosinophilic syndrome with FIP1L1/PDGFRA fusion gene effectively treated with imatinib: A case report.

RATIONALE: Hypereosinophilic syndrome (HES) is a rare disorder characterized by hypereosinophilia and organ damage. Some cases of HES are caused by the FIP1L1/PDGFRA fusion gene and respond to imatinib. FIP1L1/PDGFRA-positive HES occasionally evolves into chronic eosinophilic leukemia or into another form of myeloproliferative neoplasm; however, the development of a malignant lymphoma is very rare. We present a rare case of angioimmunoblastic T-cell lymphoma (AITL) and HES with the FIP1L1/PDGFRA gene rearrangement. PATIENT CONCERNS: A man in his 30s presented to our hospital with fever, hypereosinophilia, widespread lymphadenopathy, and splenomegaly. Laboratory tests showed hypereosinophilia, increased soluble interleukin-2 receptor, and increased vitamin B12. Positron-emission tomography with F fluorodeoxyglucose (FDG) showed positive FDG uptake in multiple enlarged lymph nodes throughout the body and the red bone marrow. A bone-marrow biopsy showed hypereosinophilia without dysplasia and an increased number of blasts. The FIP1L1/PDGFRA fusion gene was positive upon fluorescence in situ hybridization (FISH) analysis of the peripheral blood. Furthermore, biopsy of a lymph node from the neck revealed restiform hyperplasia of capillary vessels, with small lymphoma cells arranged around the capillaries. Lymphoma cells were positive for CD3, CD4, and CD10, and negative for CD20. Lymphoma cells were also positive for the FIP1L1/PDGFRA fusion gene by FISH analysis. DIAGNOSES: From these findings, the patient was diagnosed with HES and AITL with FIP1L1/PDGFRA. INTERVENTIONS: After the diagnosis, corticosteroid was administered but was ineffective. Imatinib was then administered. OUTCOMES: Imatinib was very effective for treating HES and AITL, and complete remission was achieved in both. LESSONS: This report presents the first case in which the FIP1L1/PDGFRA fusion gene was positive both in peripheral blood and lymph nodes, implying the possibility that the tumor cells acquired the FIP1L1/PDGFRA fusion gene in the early stage of hematopoietic progenitor cell developments. Imatinib was very effective in treating both HES and lymphoma, suggesting that the FIP1L1/PDGFRA fusion gene plays a key role in the pathogenesis of both HES and lymphoma.

Reticulocyte hemoglobin equivalent as a potential marker for diagnosis of iron deficiency.

Evaluation of parameters relating to serum ferritin and iron is critically important in the diagnosis of iron deficiency anemia (IDA). The recent development of automated systems for hematology analysis has made it possible to measure reticulocyte hemoglobin equivalent (RET-He), which is thought to reflect iron content in reticulocytes, in the same sample used for complete blood count tests. If RET-He is, indeed, capable of evaluating iron deficiency (ID), it would be useful for immediate diagnosis of IDA. In the present study, we examined the usefulness of RET-He for diagnosis of ID. Blood samples were obtained from 211 patients. Anemia was defined as hemoglobin (Hb) level of <12 g/dL. Iron deficiency was defined as serum ferritin level of <12 ng/mL. Patients were classified into four groups: IDA, ID, control, and non-ID with anemia. Patients in the IDA group had significantly lower RET-He levels than those in the control group. RET-He correlated with serum ferritin in the IDA and ID groups. The area under the curve for RET-He was 0.902, indicating that RET-He facilitates the diagnosis of ID with high accuracy. RET-He changed in parallel with changes in Hb during iron administration for 21 IDA patients. Our results indicate that RET-He may be a clinically useful marker for determining ID in the general population.

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.

A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines.

Hepcidin is a main regulator of iron metabolism, of which abnormal expression affects intestinal absorption and reticuloendothelial sequestration of iron by interacting with ferroportin. It is also noted that abnormal iron accumulation is one of the key factors to facilitate promotion and progression of cancer including hepatoma. By RT-PCR/agarose gel electrophoresis of hepcidin mRNA in a hepatocellular carcinoma cell line HLF, a smaller mRNA band was shown in addition to the wild-type hepcidin mRNA. From sequencing analysis, this additional band was a selective splicing variant of hepcidin mRNA lacking exon 2 of HAMP gene, producing the transcript that encodes truncated peptide lacking 20 amino acids at the middle of preprohepcidin. In the present study, we used the digital PCR, because such a small amount of variant mRNA was difficult to quantitate by the conventional RT-PCR amplification. Among seven hepatoma-derived cell lines, six cell lines have significant copy numbers of this variant mRNA, but not in one cell line. In the transient transfection analysis of variant-type hepcidin cDNA, truncated preprohepcidin has a different character comparing with native preprohepcidin: its product is insensitive to digestion, and secreted into the medium as a whole preprohepcidin form without maturation. Loss or reduction of function of HAMP gene by aberrantly splicing may be a suitable phenomenon to obtain the proliferating advantage of hepatoma cells.

In vivo behavior of NTBI revealed by automated quantification system.

Non-Tf-bound iron (NTBI), which appears in serum in iron overload, is thought to contribute to organ damage; the monitoring of serum NTBI levels may therefore be clinically useful in iron-overloaded patients. However, NTBI quantification methods remain complex, limiting their use in clinical practice. To overcome the technical difficulties often encountered, we recently developed a novel automated NTBI quantification system capable of measuring large numbers of samples. In the present study, we investigated the in vivo behavior of NTBI in human and animal serum using this newly established automated system. Average NTBI in healthy volunteers was 0.44 ± 0.076 µM (median 0.45 µM, range 0.28-0.66 µM), with no significant difference between sexes. Additionally, serum NTBI rapidly increased after iron loading, followed by a sudden disappearance. NTBI levels also decreased in inflammation. The results indicate that NTBI is a unique marker of iron metabolism, unlike other markers of iron metabolism, such as serum ferritin. Our new automated NTBI quantification method may help to reveal the clinical significance of NTBI and contribute to our understanding of iron overload.