Role of recombinant factor VIIa in the clinical management of severe postpartum hemorrhage: consensus among European experts.

OBJECTIVES: There have been significant advances in the medical management of severe postpartum hemorrhage (sPPH) over recent decades, which is reflected in numerous published guidelines. To date, many of the currently available national and international guidelines recommend recombinant factor VIIa (rFVIIa) to be used only at a very late stage in the course of sPPH, as a "last resort", before or after hysterectomy. Based on new safety data, rFVIIa has recently been approved by the European Medicines Agency (EMA) and Swissmedic for use in sPPH, if uterotonics are insufficient to achieve hemostasis, which in fact is significantly earlier in the course of postpartum hemorrhage (PPH). We therefore aimed to develop expert consensus guidance as a step toward standardizing care with the use of rFVIIa for clinicians managing women experiencing life-threatening sPPH. METHODS: The consensus process consisted of one face-to-face meeting with a group of nine experts, including eight obstetrician-gynecologists and a hematologist highly experienced in sPPH care in tertiary care perinatal centers. The panel was representative of multidisciplinary expertise in the European obstetrics community and provided consensus opinion in answer to pre-defined questions around clinical practice with rFVIIa in the management of sPPH. Recommendations have been based on current national and international guidelines, extensive clinical experience, and consensus opinion, as well as the availability of efficacy and new safety data. RESULTS: The expert panel developed 17 consensus statements in response to the 13 pre-defined questions on the use of rFVIIa in the management of sPPH including: available efficacy and safety data and the need for interdisciplinary expertise between obstetricians, anesthesiologists, and hematologists in the management of sPPH. Based on novel data, the experts recommend: (1) earlier administration of rFVIIa in patients with sPPH who do not respond to uterotonic administration to optimize the efficacy of rFVIIa; (2) the importance of hematological parameter prerequisites prior to the administration of rFVIIa to maximize efficacy; and (3) continued evaluation or initiation of further invasive procedures according to standard practice. Furthermore, recommendations on the timing of rFVIIa treatment within the sPPH management algorithm are outlined in a range of specified clinical scenarios and settings, including vaginal delivery, cesarean section, and smaller birthing units before transfer to a tertiary care center. The panel agreed that according to available, and new data, as well as real-world experience, there is no evidence that the use of rFVIIa in patients with sPPH increases the risk of thromboembolism. The authors acknowledge that there is still limited clinical effectiveness data, as well as pharmacoeconomic data, on the use of rFVIIa in sPPH, and recommend further clinical trials and efficacy investigation. CONCLUSIONS: This expert panel provides consensus guidance based on recently available data, clinical experience, and expert opinion, augmented by the recent approval of rFVIIa for use in sPPH by the EMA. These consensus statements are intended to support clinical care for sPPH and may help to provide the impetus and a starting point for updates to existing clinical practice guidelines.

Levels of procoagulant factors and peak thrombin generation in relation to dementia risk in older adults: The Cardiovascular Health Study.

INTRODUCTION: Markers of hemostasis such as procoagulant factors and peak thrombin generation are associated with cardiovascular outcomes, but their associations with dementia risk are unclear. We aimed to evaluate prospective associations of selected procoagulant factors and peak thrombin generation with dementia risk. METHODS: We measured levels of 7 hemostatic factors (fibrinogen, factor VII coagulant activity [FVIIc], activated factor VII [FVIIa], factor VIIa-antithrombin [FVIIa-AT], factor XI antigen [FXI], peak thrombin generation, and platelet count) among participants in the Cardiovascular Health Study, a cohort of older adults free of dementia in 1992/1993 (n = 3185). Dementia was adjudicated and classified by DSM-IV criteria through 1998/1999. Cox proportional hazards models estimated hazard ratios (HRs) for any dementia associated with 1-standard deviation (SD) differences, adjusting for sociodemographic and clinical factors and APOE genotype. Secondary analyses separately evaluated the risk of vascular dementia, Alzheimer's disease, and mixed dementia. RESULTS: At baseline, participants had a median age of 73 years. Over 5.4 years of follow-up, we identified 448 dementia cases. There was no evidence of linear associations between levels of these hemostatic factors with any dementia risk (HRs per 1-SD difference ranged from 1.0 to 1.1; 95 % confidence intervals included 1.0). Results of secondary analyses by dementia subtype were similar. CONCLUSIONS: In this prospective study, there was no strong evidence of linear associations between levels of fibrinogen, FVIIc, FVIIa, FVIIa-AT, FXI, peak thrombin generation, or platelet count with dementia risk. Despite their associations with cardiovascular disease, higher levels of these biomarkers measured among older adults may not reflect dementia risk.

TF-FVIIa PAR2-ß-Arrestin Signaling Sustains Organ Dysfunction in Coxsackievirus B3 Infection of Mice.

BACKGROUND: Accumulating evidence implicates the activation of G-protein-coupled PARs (protease-activated receptors) by coagulation proteases in the regulation of innate immune responses. METHODS: Using mouse models with genetic alterations of the PAR2 signaling platform, we have explored contributions of PAR2 signaling to infection with coxsackievirus B3, a single-stranded RNA virus provoking multiorgan tissue damage, including the heart. RESULTS: We show that PAR2 activation sustains correlates of severe morbidity-hemodynamic compromise, aggravated hypothermia, and hypoglycemia-despite intact control of the virus. Following acute viral liver injury, canonical PAR2 signaling impairs the restoration process associated with exaggerated type I IFN (interferon) signatures in response to viral RNA recognition. Metabolic profiling in combination with proteomics of liver tissue shows PAR2-dependent reprogramming of liver metabolism, increased lipid droplet storage, and gluconeogenesis. PAR2-sustained hypodynamic compromise, reprograming of liver metabolism, as well as imbalanced IFN responses are prevented in ß-arrestin coupling-deficient PAR2 C-terminal phosphorylation mutant mice. Thus, wiring between upstream proteases and immune-metabolic responses results from biased PAR2 signaling mediated by intracellular recruitment of ß-arrestin. Importantly, blockade of the TF (tissue factor)-FVIIa (coagulation factor VIIa) complex capable of PAR2 proteolysis with the NAPc2 (nematode anticoagulant protein c2) mitigated virus-triggered pathology, recapitulating effects seen in protease cleavage-resistant PAR2 mice. CONCLUSIONS: These data provide insights into a TF-FVIIa signaling axis through PAR2-ß-arrestin coupling that is a regulator of inflammation-triggered tissue repair and hemodynamic compromise in coxsackievirus B3 infection and can potentially be targeted with selective coagulation inhibitors.

Eptacog beta for the management of patients with haemophilia A and B with inhibitors: A European perspective.

Eptacog beta (activated), a recombinant human factor VIIa (rFVIIa), was approved by the US Food and Drug Administration (FDA) in 2020 (SEVENFACT®, LFB & HEMA Biologics) and the European Medicines Agency (EMA) in 2022 (CEVENFACTA®, LFB). In Europe, eptacog beta is indicated for the treatment of bleeds and the prevention of bleeds during surgery or invasive procedures in adults and adolescents (≥12 years old) with congenital haemophilia A or B with high-titre inhibitors (≥5 BU) or with low-titre inhibitors who are expected to have a high anamnestic response to factor VIII or factor IX, or to be refractory to increased dosing of these factors. The efficacy and safety of eptacog beta were evaluated in three Phase III clinical studies, PERSEPT 1, 2 and 3. For the EMA filing dossier, the analysis of data from PERSEPT 1 and 2 differed from the analysis used to support the filing in the US. In this review, we summarise current data regarding the mode of action, clinical efficacy and safety of eptacog beta for the management of haemophilia A and B in patients with inhibitors from a European perspective. In addition to providing a valuable summary of the analyses of the clinical data for eptacog beta conducted for the EMA, our review summarises the potential differentiators for eptacog beta compared with other current bypassing agents.

Safety of recombinant activated factor VII for treatment of breakthrough bleeds in patients with congenital haemophilia A and inhibitors receiving emicizumab prophylaxis: Review of the real-world evidence.

BACKGROUND: Emicizumab is used as a subcutaneous prophylaxis for prevention of bleeding episodes in patients with haemophilia A (HA) with and without inhibitors. While low bleeding rates were observed in clinical trials, patients still experience breakthrough bleeds (BTBs) with emicizumab in the real-world. Current guidelines recommend use of recombinant activated factor VII (rFVIIa) for treatment of BTBs in patients with inhibitors. Due to thrombotic events observed in the HAVEN 1 study, activated prothrombin complex concentrate (aPCC) should be used with caution. OBJECTIVES: The objective of this review is to identify and discuss real-world data on the frequency of BTBs and the safety of concomitant rFVIIa use in patients with inhibitors on emicizumab prophylaxis. METHODS: A search of the following databases was conducted on 15 July 2022: BIOSIS Previews® , Current Contents Search® , Embase® , MEDLINE® . Search terms included 'real world', 'haemophilia A', and 'emicizumab'. RESULTS AND CONCLUSIONS: Eleven relevant publications were identified (seven original research articles and four congress abstracts). The frequency of BTBs specifically for HA patients with inhibitors was described in three publications with 5%-56% patients on emicizumab reporting ≥1 bleeding episode. Treatment of these BTBs appeared to be managed according to relevant guidelines. Importantly, no thrombotic complications occurred during concomitant rFVIIa use. Due to the nature of real-world studies, direct comparison of the results between studies is limited. However, real-world data show that BTBs in inhibitor patients during emicizumab prophylaxis can be safely treated with rFVIIa.

Trends in the Use of Recombinant Activated Factor VII and Prothrombin Complex Concentrate in Heart Transplant Patients in Virginia.

OBJECTIVES: To explore trends in intraoperative procoagulant factor concentrate use in patients undergoing heart transplantation (HTx) in Virginia. Secondarily, to evaluate their association with postoperative thrombosis. DESIGN: Patients who underwent HTx were identified using a statewide database. Trends in off-label recombinant activated factor VII (rFVIIa) use and on-label and off-label prothrombin complex concentrate (PCC) use were tested using the Mantel-Haenszel test. Multivariate logistic regression was used to test for an association between procoagulant factor concentrate administration and thrombosis. SETTING: Virginia hospitals performing HTx. PARTICIPANTS: Adults undergoing HTx between 2012 and 2022. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 899 patients who required HTx, 100 (11.1%) received off-label rFVIIa, 69 (7.7%) received on-label PCC, and 80 (8.9%) received off-label PCC. There was a downward trend in the use of rFVIIa over the 10-year period (p = 0.04). There was no trend in on-label PCC use (p = 0.12); however, there was an increase in off-label PCC use (p < 0.001). Patients who received rFVIIa were transfused more and had longer cardiopulmonary bypass time (p < 0.001). Receipt of rFVIIa was associated with increased thrombotic risk (odds ratio [OR] 1.92; 95% CI 1.12-3.29; p = 0.02), whereas on-label and off-label PCC use had no association with thrombosis (OR 0.98, 95% CI 0.49-1.96, p = 0.96 for on-label use; and OR 0.61, 95% CI 0.29-1.30, p = 0.20 for off-label use). CONCLUSIONS: Use of rFVIIa in HTx decreased over the past decade, whereas off-label PCC use increased. Receipt of rFVIIa was associated with thrombosis; however, patients who received rFVIIa were more severely ill, and risk adjustment may have been incomplete.

Subcutaneous Marzeptacog Alfa (Activated) for On-Demand Treatment of Bleeding Events in Subjects With Hemophilia A or B With Inhibitors.

Marzeptacog alfa (MarzAA) is under development for subcutaneous treatment of episodic bleeds in patients with hemophilia A/B and was studied in a phase III trial evaluating MarzAA compared with standard-of-care (SoC) for on-demand use. The work presented here aimed to evaluate MarzAA and SoC treatment of bleeding events on a standardized four-point efficacy scale (poor, fair, good, and excellent). Two continuous-time Markov modeling approaches were explored; a four-state model analyzing all four categories of bleeding improvement and a two-state model analyzing a binarized outcome (treatment failure (poor/fair), and treatment success (good/excellent)). Different covariates impacting improvement of bleeding episodes as well as a putative relationship between MarzAA exposure and improvement of bleeding episodes were evaluated. In the final four-state model, higher baseline diastolic blood pressure and higher age (> 33 years of age) were found to negatively and positively impact improvement of bleeding condition, respectively. Bleeding events occurring in knees and ankles were found to improve faster than bleeding events at other locations. The covariate effects had most impact on early treatment success (≤ 3 hours) whereas at later timepoints (> 12 hours), treatment success was similar for all patients indicating that these covariates might be clinically relevant for early treatment response. A statistically significant relationship between MarzAA zero-order absorption and improvement of bleedings (P < 0.05) were identified albeit with low precision. No statistically significant difference in treatment response between MarzAA and intravenous SoC was identified, indicating the potential of MarzAA for treatment of episodic bleeding events with a favorable subcutaneous administration route.

CT-001, a novel fast-clearing factor VIIa, enhanced the hemostatic activity in postpartum samples.

ABSTRACT: The hemostatic system is upregulated to protect pregnant mothers from hemorrhage during childbirth. Studies of the details just before and after delivery, however, are lacking. Recombinant factor VIIa (rFVIIa) has recently been granted approval by the European Medicines Agency for the treatment of postpartum hemorrhage (PPH). A next-generation molecule, CT-001, is being developed as a potentially safer and more efficacious rFVIIa-based therapy. We sought to evaluate the peripartum hemostatic status of pregnant women and assess the ex vivo hemostatic activity of rFVIIa and CT-001 in peripartum blood samples. Pregnant women from 2 study sites were enrolled in this prospective observational study. Baseline blood samples were collected up to 3 days before delivery. Postdelivery samples were collected 45 (±15) minutes after delivery. Between the 2 time points, soluble fibrin monomer and D-dimer increased whereas tissue factor, FVIII, FV, and fibrinogen decreased. Interestingly, the postdelivery lag time and time to peak in the thrombin generation assay were shortened, and the peak thrombin generation capacity was maintained despite the reduced levels of coagulation proteins after delivery. Furthermore, both rFVIIa and CT-001 were effective in enhancing clotting activity of postdelivery samples in activated partial thromboplastin time, prothrombin time, thrombin generation, and viscoelastic hemostatic assays, with CT-001 demonstrating greater activity. In conclusion, despite apparent ongoing consumption of coagulation factors at the time of delivery, thrombin output was maintained. Both rFVIIa and CT-001 enhanced the upregulated hemostatic activity in postdelivery samples, and consistent with previous studies comparing CT-001 and rFVIIa in vitro and in in vivo, CT-001 demonstrated greater activity than rFVIIa.

Recombinant Activated Factor VII (rFVIIa) for Bleeding After Thoracic Aortic Surgery: A Scoping Review of Current Literature.

BACKGROUND: Bleeding after surgery on the thoracic aorta is a frequent complication, and can be associated with a significant increase in morbidity and mortality. Recombinant activated factor VII (rFVIIa) was developed initially for treating patients with hemophilia; however, it has been used increasingly "off-label" to achieve hemostasis after thoracic aortic procedures. OBJECTIVE: This scoping review aimed to present the available literature on the role of rFVIIa in the management of refractory postoperative bleeding after thoracic aortic surgery. METHODS/RESULTS: An electronic database search was conducted using Medline, Embase, Cochrane Library, and Google Scholar in June 2023. The authors included studies that reported the use of rFVIIa in patients undergoing surgical repair of ascending or descending aortic aneurysm or dissection. Single-case reports were excluded. Ten publications with a pooled number of 649 patients (319 patients received rFVIIa and 330 in the control groups) were identified: 3 case series, 6 retrospective studies, and 1 nonrandomized clinical trial. All studies reported the potential role of rFVIIa in correcting coagulopathy and reducing postoperative blood loss in this group of patients. Overall, there was not enough evidence to suggest that rFVIIa was associated with higher rates of thromboembolic complications or mortality. CONCLUSION: Limited evidence suggests that rFVIIa may be useful in managing postoperative refractory bleeding in patients undergoing thoracic aortic surgery. However, the impact of rFVIIa on thromboembolic complications and mortality rates remains unclear.

MicroRNA-10a enrichment in factor VIIa-released endothelial extracellular vesicles: potential mechanisms.

BACKGROUND: Factor VIIa induces the release of extracellular vesicles (EVs) from endothelial cells (EEVs). Factor VIIa-released EEVs are enriched with microRNA-10a (miR10a) and elicit miR10a-dependent cytoprotective responses. OBJECTIVES: To investigate mechanisms by which FVIIa induces miR10a expression in endothelial cells and sorts miR10a into the EVs. METHODS: Activation of Elk-1 and TWIST1 expression was analyzed by immunofluorescence microscopy and immunoblot analysis. Small interfering RNA silencing approach was used to knock down the expression of specific genes in endothelial cells. EVs secreted from endothelial cells or released into circulation in mice were isolated by centrifugation and quantified by nanoparticle tracking analysis. Factor VIIa or EVs were injected into mice; mice were challenged with lipopolysaccharides to assess the cytoprotective effects of FVIIa or EVs. RESULTS: FVIIa activation of ERK1/2 triggered the activation of Elk-1, which led to the induction of TWIST1, a key transcription factor involved in miR10a expression. Factor VIIa also induced the expression of La, a small RNA-binding protein. Factor VIIa-driven acid sphingomyelinase (ASM) activation and the subsequent activation of the S1P receptor pathway were responsible for the induction of La. Silencing of ASM or La significantly reduced miR10a levels in FVIIa-released EEVs without affecting the cellular expression of miR10a. Factor VIIa-EEVs from ASM knocked-down cells failed to provide cytoprotective responses in cell and murine model systems. Administration of FVIIa protected wild-type but not ASM-/- mice against lipopolysaccharide-induced inflammation and vascular leakage. CONCLUSION: Our data suggest that enhanced cellular expression of miR10a coupled with La-dependent sorting of miR10a is responsible for enriching FVIIa-released EVs with miR10a.

Rapid clearing CT-001 restored hemostasis in mice with coagulopathy induced by activated protein C.

BACKGROUND: Activated protein C (APC) is one of the mechanisms contributing to coagulopathy, which is associated with high mortality. The counteraction of the APC pathway could help ameliorate bleeding. However, patients also transform frequently from a hemorrhagic state to a prothrombotic state at a later time. Therefore, a prohemostatic therapeutic intervention should take this thrombotic risk into consideration. OBJECTIVES: CT-001 is a novel factor VIIa (FVIIa) with enhanced activity and desialylated N-glycans for rapid clearance. We assessed CT-001 clearance in multiple species and its ability to reverse APC-mediated coagulopathic blood loss. METHODS: The N-glycans on CT-001 were characterized by liquid chromatography-mass spectrometry. Three species were used to evaluate the pharmacokinetics of the molecule. The potency and efficacy of CT-001 under APC pathway-induced coagulopathic conditions were assessed by coagulation assays and bleeding models. RESULTS: The N-glycosylation sites of CT-001 had high occupancy of desialylated N-glycans. CT-001 exhibited 5 to 16 times higher plasma clearance in human tissue factor knockin mice, rats, and cynomolgus monkeys than wildtype FVIIa. CT-001 corrected the activated partial thromboplastin time and thrombin generation of coagulopathic plasma to normal in in vitro studies. In an APC-mediated saphenous vein bleeding model, 3 mg/kg of CT-001 reduced bleeding time in comparison with wildtype FVIIa. The correction of bleeding by CT-001 was also observed in a coagulopathic tail amputation severe hemorrhage mouse model. The efficacy of CT-001 is independent of the presence of tranexamic acid, and the combination of CT-001 and tranexamic acid does not lead to increased thrombogenicity. CONCLUSION: CT-001 corrected APC pathway-mediated coagulopathic conditions in preclinical studies and could be a potentially safe and effective procoagulant agent for addressing APC-mediated bleeding.

Thrombin generation on vascular cells in the presence of factor VIII and/or emicizumab.

BACKGROUND: The effect of factor VIII (FVIII) or emicizumab on thrombin generation is usually assessed in assays using synthetic phospholipids. Here, we assessed thrombin generation at the surface of human arterial cells (aortic endothelial cells [hAECs] and aortic vascular smooth muscle cells [hVSMCs]). OBJECTIVES: To explore the capacity of hAECs (resting or stimulated) and hVSMCs to support thrombin generation by FVIII or emicizumab. METHODS: Primary hVSMCs and hAECs were analyzed for tissue factor (TF)-activity and antigen, phosphatidylserine (PS)-exposure, tissue factor pathway inhibitor (TFPI)-content and thrombomodulin expression. Cells were incubated with FVIII-deficient plasma spiked with FVIII, emicizumab, activated prothrombin complex concentrate (APCC) or combinations thereof. RESULTS: TF activity and PS-exposure were present on both hVSMCs and hAECs. In contrast, thrombomodulin and TFPI were expressed on hAECs, while virtually lacking on hVSMCs, confirming the procoagulant nature of hVSMCs. Tumor necrosis factor α-mediated stimulation of hAECs increased not only TF antigen, TF activity, and PS-exposure but also TFPI and thrombomodulin expression. As expected, FVIII and emicizumab promoted thrombin generation on nonstimulated hAECs and hVSMCs, with more thrombin being generated on hVSMCs. Unexpectedly, FVIII and emicizumab increased thrombin generation to a lesser extent on stimulated hAECs compared with nonstimulated hAECs. Finally, adding emicizumab to FVIII did not further increase thrombin generation, whereas the addition of emicizumab to APCC resulted in exaggerated thrombin generation. CONCLUSION: Tumor necrosis factor stimulation of hAECs increases both pro- and anticoagulant activity. Unexpectedly, the increased anticoagulant activity is sufficient to limit both FVIII- and emicizumab-induced thrombin generation. This protective effect disappears when emicizumab is combined with APCC.

Retrospective Comparison of Recombinant Activated Factor VII Versus 4-Factor Prothrombin Complex Concentrate in Cardiac Surgical Patients.

OBJECTIVES: To compare the incidences of postoperative thrombotic complications, transfusion of blood products, and chest tube output in congenital cardiac surgical patients who received either recombinant activated factor VII (rFVIIa) or 4-factor prothrombin complex concentrate (4F-PCC). DESIGN: We performed a retrospective study. SETTING: Patients who underwent surgery at a tertiary academic hospital. PARTICIPANTS: Pediatric patients who underwent cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data were obtained from the Society of Thoracic Surgeons and the Pediatric Cardiac Critical Care Consortium databases, as well as from manual chart review. Adjusted p values were obtained from multivariate regression using age (days), surgeon (number), cardiopulmonary bypass time (minutes), and need for deep hypothermic circulatory arrest (yes/no). A total of 55 patients were included in the 4F-PCC group, and 89 in the rFVIIa group. The median dose of rFVIIa was 77 mcg/kg (46-88), and the median dose of 4F-PCC was 31 IU/kg (24-43). The incidences of thrombotic complications were 8% in the 4F-PCC group and 30% in the rFVIIa group (adjusted p = 0.023). No difference was reported between the groups regarding chest tube output on days 1 and 2 or transfusion of blood products. Using a sensitivity analysis with propensity matching, the incidence of thrombosis was 10% in the 4F-PCC group (n = 38), and 31% in the rFVIIa group (n = 39) (p = 0.036). No difference was reported in terms of bleeding or transfusion. CONCLUSIONS: This retrospective study suggested that the administration of rFVIIa was associated with a higher risk of thrombotic complications when compared to 4F-PCC, without benefits in terms of bleeding and transfusions.

The role of proteolytic cleavage at Arg336 and Arg372 of the A1 domain in factor VIIa/tissue factor-catalyzed reactions of B domain-deleted factor VIII.

BACKGROUND: We previously demonstrated that factor (F)VIII was rapidly activated through proteolytic cleavage at Arg372 and Arg740 by activated FVII (FVIIa)/tissue factor (TF) in very early coagulation phase, followed by inactivation by cleavage at Arg336. The influence of the absence of FVIII B domain in this series of FVIIa/TF-catalyzed reaction remains unclear, however. AIM: To examine the FVIIa/TF-catalyzed reaction of B domain-deleted (BDD-)FVIII. METHODS AND RESULTS: The FVIII activity (FVIII:C) of commercial full-length (FL-)FVIII and BDD-FVIII increased by ∼1.7-fold within 0.5 min after addition of FVIIa/TF (1 nM/0.1 nM). FVIII: C decreased to initial levels with inactivation rate constant (k; ∼0.035) within 15 min of FL-FVIII activation, but decreased gradually to initial levels (k; ∼0.017) within 30 min of BDD-FVIII activation. SDS-PAGE analyses demonstrated that the FVIIa/TF-catalyzed cleavage of BDD-FVIII occurred at Arg336 within 0.5 min in parallel with elevation of FVIII:C, but cleavage at Arg372 was not evident. FVIIa/TF-catalyzed activation of both recombinant BDD-FVIII R336A and R372A mutants that were prepared, were similar to that of wild-type (WT) BDD-FVIII. However, FVIII:C returned to initial levels (k; ∼0.046) within 30 min of R336A mutant activation, but little reduction of FVIII:C was observed with R372A mutant (k; ∼0.0046). SDS-PAGE analysis indicated that FVIIa/TF-catalyzed cleavage of WT and R372A mutant was predominant at Arg336, whereas that of R336A mutant was observed at Arg372. CONCLUSIONS: FVIIa/TF-catalyzed activation of BDD-FVIII was initiated by cleavage at Arg336, and the FVIII B domain appeared to control FVIIa/TF-catalyzed reactions by altering pattern of cleavage at Arg336 and Arg372.

COMPARING THE EFFECTIVENESS OF CONCENTRATE OF ALL PROTHROMBIN COMPLEX FACTORS WITH RECOMBINANT HUMAN COAGULATION FACTOR VIIa IN THE TREATMENT OF BLEEDING AFTER CARDIAC SURGERY.

OBJECTIVE: Aim: The authors evaluated the effectiveness of treatment with recombinant human coagulation factor VIIa and concentrate of all prothrombin complex factors in patients with massive postoperative bleeding that could not be controlled with traditional therapy. PATIENTS AND METHODS: Materials and Methods: In the period from 2020 to 2021, recombinant human coagulation factor VIIa was administered to 18 patients after cardiac surgery (group I), while the concentrate of all prothrombin complex factors was administered to 16 patients postoperatively (group II). During this period, 647 patients were operated on. The patients had normal coagulation screening tests (APTT, INR, TT, fibrinogen level, and PLT level) before surgery. Mean blood loss before and after administration of eptacog alfa and the total prothrombin complex concentrate was assessed. The mean dose of eptacog alfa was 30.95 mcg/kg b.w., and the total prothrombin complex factor concentrate dose was 14.17 mcg/kg b.w. After transfusion with red blood cell concentrate, fresh frozen plasma, and platelet concentrate, in the absence of improvement in the dynamics of postoperative drainage, it was decided to include recombinant human coagulation factor VIIa or a concentrate of all prothrombin complex factors in the treatment. RESULTS: Results: After administration of recombinant human coagulation factor VIIa at a dose of 30.95 mcg/kg b.w., bleeding stopped in 12 patients, but the remaining 6 patients required reoperation due to persistently high drainage. The decision to perform a rethoracotomy was made by a team of cardiothoracic surgeons and anesthesiologists, taking into account the dynamics of drainage (bleeding) and the hemodynamic stability of the patient. After the administration of concentrate of all prothrombin complex factors at a dose of 14.17 U/kg b.w., bleeding stopped in 12 patients. Four patients required reoperation due to persistent bleeding. CONCLUSION: Conclusions: Treatment with recombinant human coagulation factor VIIa and concentrate of all prothrombin complex factors is effective and safe for cardiac surgery patients.

Acquired factor VII deficiency in pediatric inflammatory bowel disease: Report of three cases.

Bleeding disorders can exacerbate gastrointestinal bleeding in inflammatory bowel disease (IBD) at the time of diagnosis or flares. Factor VII (FVII) deficiency is a life-threatening rare congenital bleeding disorder in childhood. This study describes three adolescent patients with IBD accompanied by acquired FVII deficiency. This is the first case series of patients with IBD accompanied by FVII deficiency. We hypothesized that inflammation, accelerated consumption, disease severity, and weight loss can cause decreased FVII activity in patients diagnosed with IBD. To control intestinal bleeding, we must keep in mind factor deficiencies in IBD.

Factor VIIa releases phosphatidylserine-enriched extracellular vesicles from endothelial cells by activating acid sphingomyelinase.

BACKGROUND: Our recent studies showed that activated factor (F) VII (FVIIa) releases extracellular vesicles (EVs) from the endothelium. FVIIa-released EVs were found to be enriched with phosphatidylserine (PS) and contribute to the hemostatic effect of FVIIa in thrombocytopenia and hemophilia. OBJECTIVE: To investigate mechanisms by which FVIIa induces EV biogenesis and enriches EVs with PS. METHODS: FVIIa activation of acid sphingomyelinase (aSMase) was evaluated by its translocation to the cell surface. The role of aSMase in the biogenesis of FVIIa-induced EVs and their enrichment with PS was investigated using specific siRNAs and inhibitors of aSMase and its downstream metabolites. Wild-type and aSMase-/- mice were injected with a control vehicle or FVIIa. EVs released into circulation were quantified by nanoparticle tracking analysis. EVs hemostatic potential was assessed in a murine thrombocytopenia model. RESULTS: FVIIa activation of aSMase is responsible for both the externalization of PS and the release of EVs in endothelial cells. FVIIa-induced aSMase activation led to ceramide generation and de novo expression of transmembrane protein 16F. Inhibitors of ceramidases, sphingosine kinase, or sphingosine-1-phosphate receptor modulator blocked FVIIa-induced expression of transmembrane protein 16F and PS externalization without interfering with FVIIa release of EVs. In vivo, FVIIa release of EVs was markedly impaired in aSMase-/- mice compared with wild-type mice. Administration of a low dose of FVIIa, sufficient to induce EVs release, corrected bleeding associated with thrombocytopenia in wild-type mice but not in aSMase-/- mice. CONCLUSION: Our study identifies a novel mechanism by which FVIIa induces PS externalization and releases PS-enriched EVs.