Hemostatic balance between pro- and anticoagulant is maintained during glucocorticoid treatment.

BACKGROUND: Glucocorticoids are associated with an increased risk of venous thrombosis. Glucocorticoid treatment increases coagulation factor and anticoagulant levels; however, its effect on hemostatic function remains unclear. This study aimed to investigate the changes in comprehensive coagulation profiles after glucocorticoid treatment in noninflammatory diseases to elucidate the direct contribution of glucocorticoids to hemostatic function. PROCEDURE: Patients diagnosed with primary immune thrombocytopenia requiring glucocorticoid treatment were prospectively enrolled in this study. Changes in coagulation factors and anticoagulants during glucocorticoid treatment and changes in thrombin generation potential were determined in the absence and presence of soluble thrombomodulin (sTM). RESULTS: Seven treatment cases (four for steroid pulse therapy and three for oral glucocorticoid therapy) in six patients with immune thrombocytopenia were examined. After glucocorticoid treatment, activated partial thromboplastin time significantly shortened, and activities of factor VIII, IX, XI, and XII significantly increased, except for von Willebrand factor antigen. Moreover, antithrombin and protein C (PC) activities significantly increased after glucocorticoid treatment. Two major parameters of thrombin generation potential, endogenous thrombin potential (ETP) and peak thrombin (Peak), significantly increased in the absence of sTM after glucocorticoid treatment. However, no significant increases in either parameter were observed in the presence of sTM. ETP-TM and Peak-TM ratios, which represent resistance to the anticoagulant effect of the PC pathway, significantly decreased after glucocorticoid treatment, suggesting that anticoagulant function via the PC pathway is elevated after glucocorticoid treatment. CONCLUSIONS: As glucocorticoids increase intrinsic coagulation factor and anticoagulant levels, hemostatic balance between pro- and anticoagulant functions is maintained.

C-terminal residues of activated protein C light chain contribute to its anticoagulant and cytoprotective activities.

BACKGROUND: Activated protein C (APC) is an important homeostatic blood coagulation protease that conveys anticoagulant and cytoprotective activities. Proteolytic inactivation of factors Va and VIIIa facilitated by cofactor protein S is responsible for APC's anticoagulant effects, whereas cytoprotective effects of APC involve primarily the endothelial protein C receptor (EPCR), protease activated receptor (PAR)1 and PAR3. OBJECTIVE: To date, several binding exosites in the protease domain of APC have been identified that contribute to APC's interaction with its substrates but potential contributions of the C-terminus of the light chain have not been studied in detail. METHODS: Site-directed Ala-scanning mutagenesis of six positively charged residues within G142-L155 was used to characterize their contributions to APC's anticoagulant and cytoprotective activities. RESULTS AND CONCLUSIONS: K151 was involved in protein S dependent-anticoagulant activity of APC with some contribution of K150. 3D structural analysis supported that these two residues were exposed in an extended protein S binding site on one face of APC. Both K150 and K151 were important for PAR1 and PAR3 cleavage by APC, suggesting that this region may also mediate interactions with PARs. Accordingly, APC's cytoprotective activity as determined by endothelial barrier protection was impaired by Ala substitutions of these residues. Thus, both K150 and K151 are involved in APC's anticoagulant and cytoprotective activities. The differential contribution of K150 relative to K151 for protein S-dependent anticoagulant activity and PAR cleavage highlights that binding exosites for protein S binding and for PAR cleavage in the C-terminal region of APC's light chain overlap.

Cerebral cavernous malformations form an anticoagulant vascular domain in humans and mice.

Cerebral cavernous malformations (CCMs) are common brain vascular dysplasias that are prone to acute and chronic hemorrhage with significant clinical sequelae. The pathogenesis of recurrent bleeding in CCM is incompletely understood. Here, we show that central nervous system hemorrhage in CCMs is associated with locally elevated expression of the anticoagulant endothelial receptors thrombomodulin (TM) and endothelial protein C receptor (EPCR). TM levels are increased in human CCM lesions, as well as in the plasma of patients with CCMs. In mice, endothelial-specific genetic inactivation of Krit1 (Krit1 ECKO ) or Pdcd10 (Pdcd10 ECKO ), which cause CCM formation, results in increased levels of vascular TM and EPCR, as well as in enhanced generation of activated protein C (APC) on endothelial cells. Increased TM expression is due to upregulation of transcription factors KLF2 and KLF4 consequent to the loss of KRIT1 or PDCD10. Increased TM expression contributes to CCM hemorrhage, because genetic inactivation of 1 or 2 copies of the Thbd gene decreases brain hemorrhage in Pdcd10 ECKO mice. Moreover, administration of blocking antibodies against TM and EPCR significantly reduced CCM hemorrhage in Pdcd10 ECKO mice. Thus, a local increase in the endothelial cofactors that generate anticoagulant APC can contribute to bleeding in CCMs, and plasma soluble TM may represent a biomarker for hemorrhagic risk in CCMs.

First case report of hemophilia B Leyden in Japan.

Hemophilia B Leyden is a unique subtype of hemophilia B, characterized by increasing factor IX activity (FIX:C) after puberty and a lower normal range of FIX:C throughout adulthood. However, to date, no Japanese case has been reported. Here, we report a case of hemophilia B Leyden in a 22-year-old male. He suffered from subgaleal hematoma, and was subsequently diagnosed with hemophilia B (FIX:C 0.2%) in the neonatal period. Both his parents are Japanese. There was no history of hemophilia in his family. FIX:C gradually increased with age (8% at age = 1; 14% at age = 7; 19% at age = 12; 32% at age = 18). FIX:C is within the range 30-40% in recent several years. He once required administration of FIX concentrate against traumatic tongue bleeding at 7 years of age. Genotyping analysis of FIX was performed after informed consent at 21 years of age, and a point mutation (c.-35G>A) was detected. This mutation has been reported previously as the Leyden mutation. Although it has been reported that hemophilia B Leyden is seen in 1.9% of patients with hemophilia B, the present case is the first report of hemophilia B Leyden from Japan.

A cohort study of the usefulness of primary prophylaxis in patients with severe haemophilia A.

Primary prophylaxis is a method of haemostatic management to prevent bleeding and arthropathy in patients with severe haemophilia. The aim of this study was to evaluate the usefulness of primary prophylaxis in patients with severe haemophilia A. This study included 15 patients with haemophilia A who received primary prophylaxis at our institution for a minimum of 5 years. We evaluated the annualized bleeding ratio of joints or other sites, current joint function, and X-ray images and MRI scans taken when patients were 6 years old. The range of patients' ages at the end of the study was 6.2-16.8 years, and at the start of primary prophylaxis it was 0.8-2.4 years. Factor VIII concentrates (25-40 units kg(-1) dose(-1)) were administered 3 times/week or every other day, according to the Swedish protocol. Mean joint and non-joint annualized bleeding ratios were 0.49 ± 0.5 and 1.54 ± 1.69, respectively. At the final evaluation, all patients displayed a normal range of motion for both elbows, knees, and ankles. The radiography and MRI findings at the age of 6 were unremarkable in all patients. Overall, primary prophylaxis for patients with severe haemophilia A was performed safely, reduced the number of bleeding events, and prevented progression to arthropathy.

[Efficacy of chemotherapy combined with bortezomib for two cases of relapsed/refractory acute lymphoblastic leukemia].

Bortezomib (BZM), a proteasome inhibitor, was recently reported to be effective against acute lymphoblastic leukemia (ALL). We report two cases of relapsed/refractory ALL, who were treated with BZM (1.3 mg/m2/dose, 2 doses/week for 2 weeks) in combination with vincristine, doxorubicin, dexamethasone, and L-asparaginase (L-ASP). The first patient was a 16-year-old girl who developed a bone marrow relapse 8 months after the initial diagnosis during consolidation chemotherapy. She received BZM-combined chemotherapy without L-ASP considering her previous history of an allergic reaction to L-ASP. The BZM-combined regimen was discontinued due to interstitial pneumonia development on day 13, and the interstitial pneumonia was successfully treated with steroid pulse therapy. Although her elevated serum LDH transiently normalized on day 16, blasts in peripheral blood did not disappear, and she died of leukemia without achieving remission. The second patient was a 17-year-old girl who developed a third bone marrow relapse after cord blood transplantation. She was given the same BZM combined regimen. Although the BZM-combined regimen was discontinued due to acute pancreatitis development on day 12, complete remission without platelet recovery was confirmed on day 62. Our experience suggests not only the effectiveness of BZM-combined chemotherapy but also the importance of controlling its toxicities when administered as a salvage therapy for advanced ALL patients.