PDPN/CLEC-2 axis modulates megakaryocyte subtypes in a hematopoietic stem cell-regulating megakaryocyte-dominant manner.

Introduction: Megakaryocytes are classified into several subtypes including LSP1-positive immune-skewed, MYLK4-positive hematopoietic stem cell (HSC)-regulating, and BMAL1-positive platelet-producing megakaryocytes. Podoplanin (PDPN)-expressing stromal cells generate a microenvironment that promotes megakaryopoiesis in the bone marrow. In this context, PDPN interacts with C-type lectin-like receptor-2 (CLEC-2) on megakaryocyte progenitors, which induces megakaryocyte proliferation.

Misleading antigenic von Willebrand factor levels in acquired von Willebrand syndrome secondary to monoclonal gammopathy of undetermined significance.

In the diagnosis and treatment of acquired von Willebrand syndrome (AVWS), von Willebrand factor (VWF) antigen levels (VWF:Ag) are helpful for quantifying blood VWF-protein levels. Most clinical laboratories measure VWF:Ag by latex immunoassay (LIA), but underlying diseases of AVWS may influence LIA results. A 60 year-old AVWS patient with immunoglobulin G (IgG) kappa-type monoclonal gammopathy of undetermined significance (MGUS) showed reduced VWF activity but normal levels of VWF:Ag.

Newly diagnosed multiple myeloma with bleeding and coagulation abnormalities caused by a thrombin-inhibiting substance.

Approximately 7% of patients with newly diagnosed multiple myeloma (MM) experience bleeding complications with varying causes, but few reports have described these complications. Here we report the case of a patient with newly diagnosed MM who presented with a bleeding tendency and various coagulation abnormalities. Chromogenic assays, thrombin time, and reptilase time revealed the presence of a thrombin-inhibiting substance that inhibited release of fibrinopeptide A from fibrinogen.

Variability in combinations of APTT reagent and substrate plasma for a one-stage clotting assay to measure factor VIII products.

Introduction: An investigation of the suitability of reagents for measuring FVIII products in a one-stage clotting assay (OSA) showed variations in their FVIII activity (FVIII:C). Most studies have focused on the activated partial thromboplastin time (APTT) reagent rather than FVIII-deficient plasma (F8DP), even though the APTT-based OSA is comprised of APTT reagents and factor-deficient plasma.

Aim: A single-centre study was conducted to clarify variations in measurements of FVIII products in an OSA using a total of 12 reagent combinations, including four APTT reagents and three types of F8DP.

Basement membrane extract potentiates the endochondral ossification phenotype of bone marrow-derived mesenchymal stem cell-based cartilage organoids.

Endochondral ossification is a developmental process in the skeletal system and bone marrow of vertebrates. During endochondral ossification, primitive cartilaginous anlages derived from mesenchymal stem cells (MSCs) undergo vascular invasion and ossification. In vitro regeneration of endochondral ossification is beneficial for research on the skeletal system and bone marrow development as well as their clinical aspects.

Real-world data of MDS and CMML in Japan: results of JALSG clinical observational study-11 (JALSG-CS-11).

We conducted a multicenter, prospective observational study of acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia (CMML) in Japan. From August 2011 to January 2016, we enrolled 6568 patients. Herein, we report the results for MDS (n = 2747) and CMML (n = 182).

Real-world data of AML in Japan: results of JALSG clinical observational study-11 (JALSG-CS-11).

This report covers acute myeloid leukemia (AML) results from a multicenter, prospective observational study of AML, myelodysplastic syndromes, and chronic myelomonocytic leukemia in Japan. From August 2011 to January 2016, 3728 AML patients were registered. Among them, 42% were younger than 65, and the male-to-female ratio was 1.

Prolonged COVID-19 Infection in a Patient with Complete Remission from Follicular Lymphoma with Hyperosmolar Hyperglycemic Syndrome.

An 81-year-old woman undergoing B-cell depletion therapy developed COVID-19 and a hyperglycemic hyperosmotic state. She had a history of multiple vaccinations against coronaviruses but had persistent antigen positivity. Strategies to prevent the development of COVID-19 in immunosuppressed patients have not been established.

Outcomes of transplant-eligible patients with myelodysplastic syndrome with excess blasts registered in an observational study: The JALSG-CS11-MDS-SCT.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is the sole curative therapy for myelodysplastic syndrome (MDS). However, whether bridging therapy (BRT) including azacitidine (AZA) and combination chemotherapy (CCT) prior to allo-SCT should be performed is unclear. We analyzed BRT and the outcomes of patients with myelodysplastic syndrome with excess blasts (MDS-EB) who were ≤ 70 years old at the time of registration for a prospective observational study to clarify the optimal allo-SCT strategy for high-risk MDS.

The usefulness of tranexamic acid for bleeding symptoms of chronic consumptive coagulopathy complicated by aortic disease: a single-institute, retrospective study of 14 patients.

Background: Tranexamic acid (TXA) is an antifibrinolytic drug that blocks lysine-binding sites on the profibrinolytic enzyme plasminogen. Aortic diseases with chronic consumption coagulopathy may lead to disseminated intravascular coagulation (DIC) and cause fatal bleeding. Although the use of antifibrinolytic agents in DIC is generally not recommended due to enhanced fibrin deposition risking thrombotic symptoms, the efficacy of TXA has been reported in several cases of DIC with aortic diseases.

VWF-Gly2752Ser, a novel non-cysteine substitution variant in the CK domain, exhibits severe secretory impairment by hampering C-terminal dimer formation.

Background: Von Willebrand factor (VWF) is a multimeric glycoprotein that plays important roles in hemostasis and thrombosis. C-terminal interchain-disulfide bonds in the cystine knot (CK) domain are essential for VWF dimerization. Previous studies have reported that missense variants of cysteine in the CK domain disrupt the intrachain-disulfide bond and cause type 3 von Willebrand disease (VWD).

F9 mRNA splicing aberration due to a deep Intronic structural variation in a patient with moderate hemophilia B.

Introduction: Hemophilia B (HB) is a hereditary bleeding disorder caused by the genetic variation of the coagulation factor IX (FIX) gene (F9). Several F9 structural abnormalities, including large deletion and/or insertion, have been observed to cause HB development. However, there is limited information available on F9 deep intronic variations.

Periosteum-derived podoplanin-expressing stromal cells regulate nascent vascularization during epiphyseal marrow development.

Bone marrow development and endochondral bone formation occur simultaneously. During endochondral ossification, periosteal vasculatures and stromal progenitors invade the primary avascular cartilaginous anlage, which induces primitive marrow development. We previously determined that bone marrow podoplanin (PDPN)-expressing stromal cells exist in the perivascular microenvironment and promote megakaryopoiesis and erythropoiesis.

Development and validation of a novel qualitative test for plasma fibrinogen utilizing clot waveform analysis.

Plasma fibrinogen is commonly examined by Clauss fibrinogen assay, which cannot distinguish between quantitative and qualitative fibrinogen anomalies. However, our previously reported Clauss fibrinogen assay utilizing clot waveform analysis (Clauss-CWA) provides additional information that contributes to the classification of fibrinogen anomalies. In this study, we adopted the Clauss-CWA method for an autoanalyzer to automatically measure the antigenic estimate (eAg) of fibrinogen in addition to the functional amount (Ac), and to thus provide the Ac/eAg ratio as a qualitative indicator.

Protein S-Leu17Pro disrupts the hydrophobicity of its signal peptide causing a proteasome-dependent degradation.

Introduction: Protein S is a vitamin K-dependent glycoprotein with important anticoagulant, fibrinolytic, anti-inflammatory, anti-apoptotic, and cytoprotective functions. Congenital protein S deficiency is an autosomal dominant thrombophilia due to protein S gene (PROS1) variations. Our group identified a variation in PROS1 that translates into protein S deficiency: c.

Elevated red blood cell distribution width is associated with poor outcome in osteoporotic vertebral fracture.

Introduction: Red blood cell distribution width (RDW) has been evaluated as a potential screening marker for cancer and prognostic marker in heart failure and coronary heart disease. Recent studies have been suggested the association of RDW with mortality in patients with hip fracture and arthroplasty. Objective of this study was to investigate whether RDW as a prognostic marker is significant in patients with osteoporotic vertebral fracture (OVF).

Anemia in older adults as a geriatric syndrome: A review.

Anemia, a frequently occurring condition in older patients, has no standard definition; however, in most studies, it is defined as hemoglobin level <12 and <13 g/dL in women and men, respectively. Approximately 10% of older adults living in the community have anemia. The prevalence of anemia is significantly correlated with advanced age and male sex.

R702C is associated with erythroid abnormality with splenomegaly in mice.

disorders are characterized by giant platelets, thrombocytopenia, and Döhle body-like cytoplasmic inclusion bodies in granulocytes. However, whether these disorders cause any changes in erythroid cells has yet to be determined. This study analyzed the influence of R702C, as one of the most commonly detected disorders, on erythroid cells in a mouse model.

Essential role of a carboxyl-terminal α-helix motif in the secretion of coagulation factor XI.

Background: Coagulation factor XI (FXI) is a plasma serine protease zymogen that contributes to hemostasis. However, the mechanism of its secretion remains unclear.

Objective: To determine the molecular mechanism of FXI secretion by characterizing a novel FXI mutant identified in a FXI-deficient Japanese patient.

Impact of variation in reagent combinations for one-stage clotting assay on assay discrepancy in nonsevere haemophilia A.

Introduction: Factor VIII activity (FVIII:C) is measured by one-stage clotting assay (OSA) or chromogenic substrate assay (CSA). Significant differences in FVIII:C between OSA (FVIII:C ) and CSA (FVIII:C ) are described as assay discrepancy in nonsevere haemophilia A (HA). A large number of reagent combinations (APTT reagent and FVIII-deficient plasma) are used for OSA, but the impact of variations in reagent combinations on assay discrepancy has not been fully characterized.

Aberrant X chromosomal rearrangement through multi-step template switching during sister chromatid formation in a patient with severe hemophilia A.

Background: Hemophilia A (HA) is an X-linked recessive bleeding disorder caused by pathogenic variants of the coagulation factor VIII gene (F8). Half of the patients with severe HA have a recurrent inversion in the X chromosome, that is, F8 intron 22 or intron 1 inversion. Here, we characterized an abnormal F8 due to atypical complex X chromosome rearrangements in a Japanese patient with severe HA.

Apparent synonymous mutation F9 c.87A>G causes secretion failure by in-frame mutation with aberrant splicing.

Introduction: Hemophilia B is an X-linked recessive bleeding disorder caused by coagulation factor IX (FIX) gene (F9) mutations. Several F9 synonymous mutations have been known to cause hemophilia B; however, the deleterious mechanisms underlying the development of hemophilia B have not been completely understood. To elucidate the molecular pathogenesis causing hemophilia B, we investigated the synonymous F9 mutation: c.

Molecular basis of SERPINC1 mutations in Japanese patients with antithrombin deficiency.

Background: Congenital antithrombin (AT) deficiency, which arises from various SERPINC1 defects, is an autosomal-dominant thrombophilic disorder associated with a high risk of recurrent venous thromboembolism.

Patients/methods: We investigated SERPINC1 defects in Japanese patients with congenital AT deficiency who developed venous thromboembolism or had a family history of deep vein thrombosis. We analyzed the full DNA sequences of SERPINC1 exons and exon-intron junctions by PCR-mediated direct sequencing.