Fluvastatin suppresses hemin-induced cell death, reactive oxygen species generation, and elevated labile iron pool.

Background: In transfusion-related iron overload, macrophage/reticuloendothelial cells are the first site of haem-derived iron accumulation. The prevention of haem-induced cytotoxicity in macrophages may represent a target for iron overload treatment. Deferasirox, an oral iron chelator, has been used to treat transfusion-related iron overload however, low adherence to the therapy is an issue.

Deferasirox, an iron-chelating agent, alleviates acute lung inflammation by inhibiting neutrophil activation and extracellular trap formation.

Objective: Reactive oxygen species (ROS) production by neutrophils induces pulmonary endothelial cell damage and results in acute lung injury (ALI). We previously reported that deferasirox (DFS), an iron-chelating agent, inhibits the ROS production and neutrophil extracellular trap (NET) formation induced by phorbol myristate acetate and formylmethionylleucylphenylalanine . In the present study, we investigated the effects of DFS using a mouse model of lipopolysaccharide (LPS)-induced ALI.

After haemin treatment intracellular non-haem iron increases prior to haem oxygenase-1 induction: A study in human monocytic cell line THP-1.

Background: Iron overload is a major health concern for transfusion-dependent patients. Repeated transfusions result in the loading of large amounts of haem-derived iron on macrophages, in turn, inducing cell death. We previously demonstrated that haemin-induced cell death in human monocytic THP-1 cells is consistent with ferroptosis, an iron-dependent cell death regulation mechanism.

Detection of activated neutrophils by reactive oxygen species production using a hematology analyzer.

Neutrophils are recruited to infection sites and kill bacteria by phagocytosis and reactive oxygen species (ROS) production. It has been reported that vacuoles are present in neutrophils that produce ROS and are present in large numbers in blood smears of patients with bacterial infections. The leukocyte differentiation function on the Sysmex automated hematology analyzer classifies leukocytes by flow cytometry.

Haemin-induced cell death in human monocytic cells is consistent with ferroptosis.

Background: Iron overload is a major issue for transfusion-dependent patients. Repeated transfusions result in the loading of large amounts of haem-derived iron on macrophages, and the haemin in turn induces cell death and the generation of reactive oxygen species (ROS) in both murine macrophages and human monocytic THP-1 cells. This haemin-induced cell death process has been shown to be iron-dependent.

Quantitative analysis of hemin-induced neutrophil extracellular trap formation and effects of hydrogen peroxide on this phenomenon.

Formation of neutrophil extracellular traps (NETs) can perpetuate sterile inflammation; thus, it is important to clarify their pathophysiological characteristics. Free heme, derived via hemolysis, is a major contributor to organ damage, and reportedly induces neutrophil activation as well as reactive oxygen species (ROS) production and NET formation. For this study, we examined hemin (Fe -protoporphyrin IX)-induced NET formation quantitatively in vitro as well as the effects of oxidative stress.

Iron-chelating agent, deferasirox, inhibits neutrophil activation and extracellular trap formation.

Iron-chelating agents, which are frequently prescribed to transfusion-dependent patients, have various useful biological effects in addition to chelation. Reactive oxygen species (ROS) produced by neutrophils can cause pulmonary endothelial cell damage, which can lead to acute lung injury (ALI). We previously reported that deferasirox (DFS), an iron-chelating agent, inhibits phorbol myristate acetate (PMA) or formyl-methionyl-leucyl-phenylalanine (fMLP)-induced ROS production in neutrophils, in vitro.

Heme-related molecules induce rapid production of neutrophil extracellular traps.

Background: Pulmonary endothelial cell damages caused by neutrophil overactivation could result in acute lung injuries including transfusion-related acute lung injury (TRALI). We previously reported that heme-related molecules derived from hemolysis induced the production of reactive oxygen species from neutrophils. Recently, neutrophil extracellular traps (NETs) have been demonstrated to associate with the onset of TRALI.

[Effects of four bisphosphonates on macrophage phagocytosis: quantitative measurement by flow cytometry using high-fluorescence particles and human monocytic cell line THP-1].

Impairment of macrophage phagocytosis is a major cause of chronic inflammation. Bisphosphonates (BPs) are widely used as anti-osteoclastic agents. The effects of BPs on monocyte-macrophage lineage cells are being increasingly reported; however, the detailed effects of BPs on macrophage phagocytic activity are still unclear.

Deferasirox reduces oxidative stress in patients with transfusion dependency.

Background: Iron chelation therapy is useful against the over-accumulation of iron and is expected to reduce oxidative stress resulting from the Fenton reaction and Haber-Weiss reaction. We monitored oxidative status and serum ferritin levels after in vivo administration of deferasirox (DFS) and studied the in vitro effects of iron chelators on neutrophil function.

Methods: Nine patients suffering from transfusion dependency were recruited for this study, and derivatives of reactive oxygen metabolite (dROM) tests to detect serum hydroperoxide levels were evaluated in addition to serum ferritin levels.

Comparative analysis of remission induction therapy for high-risk MDS and AML progressed from MDS in the MDS200 study of Japan Adult Leukemia Study Group.

A total of 120 patients with high-risk myelodysplastic syndrome (MDS) and AML progressed from MDS (MDS-AML) were registered in a randomized controlled study of the Japan Adult Leukemia Study Group (JALSG). Untreated adult patients with high-risk MDS and MDS-AML were randomly assigned to receive either idarubicin and cytosine arabinoside (IDR/Ara-C) (Group A) or low-dose cytosine arabinoside and aclarubicin (CA) (Group B). The remission rates were 64.

[Activation of human neutrophils by hemin].

Activation of neutrophils by free heme is considered as one of the mechanisms for cellular dysfunction under the conditions of hemorrhage or tissue damage. We studied about the effects of hemin, ferriprotoporphyrin IX, on human neutrophil activation by measurements of adhesion molecule expression and reactive oxygen species (ROS) production. Human neutrophils purified from heparinized blood of healthy volunteers were stimulated with hemin.

[Neutrophil function tests and oxidative stress detection as clinical examinations].

We herein introduce several clinically available methods to detect neutrophil function and oxidative stress. The flowcytometric detection of adhesive protein expression, such as CD11b(Mac-1), assessment of phagocytosis activity, and measurement of reactive oxygen species (ROS) production are relatively easy to apply as tools for laboratory medicine. A new device to simultaneously detect superoxide and calcium ion influx is also introduced.

[Laboratory medicine for blood transfusion and transplantation medicine].

We discussed the usefulness of routine technologies of laboratory medicine in blood transfusion and transplantation medicine. New parameters that can be measured by automated hematology analyzers have been clinically evaluated and proven to be useful so far. Based on our experience, detection systems for fragmented red cells (FRC), immature platelets (immature platelet function, IPF), and hematopoietic progenitor cells (HPC) are useful for the diagnosis of thrombotic microangiopathy, differential diagnosis of thrombocytopenia, and decision regarding the optimal timing to collect peripheral stem cells, respectively.

Albumin attenuates neutrophil activation induced by stimulators including antibodies against neutrophil-specific antigens.

As neutrophil activation is related to several adverse transfusion reactions, we studied about the activation induced by anti-neutrophil antibodies and the stabilizing effects of albumin pretreatment by means of flow cytometry. Anti-neutrophil monoclonal antibody (anti-HNA-1a, 1b, 2a) alone induced CD11b expression and shedding of L-selectin, and anti-HNA-1a reinforced reactive oxygen species (ROS) production. Albumin pretreatment significantly reduced CD11b expression and L-selectin shedding induced by fMLP and ROS production induced by PMA, G-CSF combined with PMA or LPS-fMLP, or anti-HNA-1a combined with PMA.

Usefulness of sequential automated analysis of fragmented red blood cells for the differential diagnosis of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome following allogeneic hematopoietic cell transplantation.

Differentiating thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) from other complications following allogeneic hematopoietic cell transplantation (HPCT) requires objective, reliable markers. To this purpose, we assessed the clinical usefulness of sequential quantified analysis of fragmented red blood cells (FRC) with the Sysmex XE-2100 automated hematology analyzer. The correlation between manual and automated counting was significant (r = 0.

Usefulness of particle image analyzer for evaluation of fragmented red cells.

Quantitative determination of fragmented red cells (FRCs) in peripheral blood is useful in various clinical fields. We have previously reported an automatic detection method using a hematology analyzer essentially based on detection of small red cells. We then tried to use another instrument, the FPIA 2100, to reflect the characteristic morphology of red cells.

Von Willebrand factor-cleaving protease activity remains at the intermediate level in thrombotic thrombocytopenic purpura.

A 59-year-old woman, diagnosed with chronic myelogenous leukemia (chronic phase) and treated with interferon-alpha for 13 years, developed renal failure. Renal biopsy showed thrombotic thrombocytopenic purpura, but intensive therapy including plasma exchange and steroid administration was not effective. The activity of von Willebrand factor-cleaving protease was detectable at the intermediate level (15-46%) during the clinical course, suggesting that this case was not compatible with the previously reported pattern of idiopathic or drug-induced thrombotic thrombocytopenic purpura, but with the pattern associated with malignant disease or immunological disorders.

Cyclosporin neurotoxicity with Epstein-Barr virus-associated hemophagocytic syndrome.

In September 2000, a 22-year-old female was admitted to our hospital due to high grade fever, liver enzymes elevation and pancytopenia. Bone marrow aspiration was performed, and hemophagocytosis was present. Epstein-Barr virus (EBV) DNA was positive in her peripheral blood, and we diagnosed the case as EBV-associated hemophagocytic syndrome (EB-VAHS) after excluding other malignancies.

Second case of CML with aberrant BCR-ABL fusion transcript (e8/a2) with insertion of an inverted ABL intron 1b sequence.

We found a case of Ph-positive chronic myelogenous leukemia (CML) patient with an atypical BCR-ABL transcript that was undetectable by a routine reverse transcription polymerase chain reaction (RT-PCR) for major BCR-ABL. Additional RT-PCR and sequence analyses have demonstrated that the aberrant transcript consists of a fusion of BCR exon 8 (e8) and ABL exon 2 (a2) with an insertion of a 55-bp inverted sequence of intron 1b between them. The nucleotide sequences of the aberrant transcript were identical to those of a previously reported CML patient.

Noninvasive monitoring of hemoglobin. The effects of WBC counts on measurement.

The efficacy of a noninvasive hemoglobin monitoring device (Astrin, Sysmex, Kobe, Japan) was evaluated for healthy volunteers and for patients with hematologic disorders. At the same time, the effects of WBC counts on noninvasive monitoring were studied by clinical evaluation and in ex vivo experiments. The hemoglobin levels determined by the device (Ast-Hb) and a conventional analyzer (T-Hb) were compared.