scholarly journals Normalization of markers of coagulation activation with a purified protein C concentrate in adults with homozygous protein C deficiency

Blood ◽  
1993 ◽  
Vol 82 (4) ◽  
pp. 1159-1164 ◽  
Author(s):  
J Conard ◽  
KA Bauer ◽  
A Gruber ◽  
JH Griffin ◽  
HP Schwarz ◽  
...  

Homozygous or double heterozygous protein-C deficiency can present at birth with purpura fulminans or later in life with venous thrombosis. Two homozygous patients who had previously sustained thrombotic episodes were investigated at a time when they were asymptomatic and not receiving antithrombotic therapy. The plasma levels of protein-C antigen and activity in both individuals were approximately 20% of normal. We administered a highly purified plasma-derived protein C concentrate to these individuals and monitored levels of several markers of in vivo coagulation activation. Assays for protein-C activation (activated protein C and protein C activation peptide) showed a sustained increase from reduced baseline levels, whereas thrombin generation (as measured by prothrombin fragment F1 + 2) gradually decreased over about 24 hours into the normal range. These investigations provide direct evidence that protein C is converted to activated protein C in vivo, and that the protein-C anticoagulant pathway is a tonically active mechanism in the regulation of hemostatic system activation in humans.

Blood ◽  
1993 ◽  
Vol 82 (4) ◽  
pp. 1159-1164 ◽  
Author(s):  
J Conard ◽  
KA Bauer ◽  
A Gruber ◽  
JH Griffin ◽  
HP Schwarz ◽  
...  

Abstract Homozygous or double heterozygous protein-C deficiency can present at birth with purpura fulminans or later in life with venous thrombosis. Two homozygous patients who had previously sustained thrombotic episodes were investigated at a time when they were asymptomatic and not receiving antithrombotic therapy. The plasma levels of protein-C antigen and activity in both individuals were approximately 20% of normal. We administered a highly purified plasma-derived protein C concentrate to these individuals and monitored levels of several markers of in vivo coagulation activation. Assays for protein-C activation (activated protein C and protein C activation peptide) showed a sustained increase from reduced baseline levels, whereas thrombin generation (as measured by prothrombin fragment F1 + 2) gradually decreased over about 24 hours into the normal range. These investigations provide direct evidence that protein C is converted to activated protein C in vivo, and that the protein-C anticoagulant pathway is a tonically active mechanism in the regulation of hemostatic system activation in humans.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 61-61
Author(s):  
M. Anna Kowalska ◽  
Michele P. Lambert ◽  
Lubica Rauova ◽  
William J. Smith ◽  
Shawn A. Mahmud ◽  
...  

Abstract Infusion of activated protein C (APC) improves survival in sepsis. PF4 is a CXC chemokine predominantly expressed during megakaryopoiesis and stored in platelet alpha-granules whose biological function(s) are not well understood. We have shown that recombinant PF4 enhances APC generation by thrombin/thrombomodulin complexes both in vitro and in vivo. Would endogenous PF4 released from platelets activated during an inflammatory state similarly affect APC production? We addressed this issue using mice that were either completely devoid of PF4 (mPF4−/−) or had a 6-fold excess of human PF4 (hPF4+). Using a lethal LPS challenge model (O111:B4, 40 mg/kg IP), we examined whether platelets become activated and release PF4 during endotoxemia. Two hours after LPS injection, the platelet count in mice decreased to ~70% of baseline levels (p=0.006). Serum PF4, as measured by ELISA, also dropped to ~60% of baseline from 47±5 kU/ml to 30±5 kU/ml (p=0.002). At the same time, plasma PF4 level was increased by 20%, consistent with LPS resulting in PF4 release. The smaller increase than expected suggests that much of the released PF4 binds immediately to the surface of vascular cells. Consistent with this, we have observed higher accumulation of PF4 in mouse lungs after LPS injection compared to uninjected mice (990±220 and 660±120 U/mg, respectively, p=0.017). APC generation was assessed 10 min after thrombin infusion (80 U/kg. IV) as a measure of endogenous platelet PF4’s effect in an inflammatory/procoagulant state. In mPF4−/− mice APC levels were 72% of that in wild type (WT) mice (p=0.0006) while in hPF4+ mice APC formation increased to 178% (p=0.003). Survival of mice 24 hrs after LPS (25 mg/kg) challenge was then examined. hPF4+ mice had a mortality rate of 9% compared to ~40% in both WT and mPF4−/− (p< 0.001). To examine the role of APC in this improved survival, we performed similar experiments with mice heterozygous for protein C deficiency (PC+/−). More PC+/− mice died 16 hrs after injection of 40 mg/kg LPS than WT mice (61% vs. 29% mortality respectively, p=0.005), while mortality for hPF4+/PC+/− mice was significantly lower (14%, p< 0.001 compared to PC+/− mice), supporting the hypothesis that the protective effect of PF4 is at least in part due to increased APC generation. Next we asked if infusion of platelets with high PF4 is protective in the LPS model. We injected either vehicle buffer or mPF4−/− or hPF4+ platelets (3×108 per 20 g mouse) into WT mice prior to treatment with LPS. Mortality of mice at 24 hrs after LPS injection with mPF4−/−platelet infusion was not significantly different than mice with buffer infusion (86% vs. 96% respectively, p=0.4), but mortality was significantly lower when hPF4+ platelets were infused (58% vs. 96%, p=0.01). Our results suggest that PF4 is released from platelets after an inflammatory stimulus and that this may have a positive physiological role by enhancing APC generation. High endogenous platelet PF4 levels may have a survival advantage after exposure to endotoxins. Infusion of platelets containing high levels of PF4 in sepsis may be a novel therapeutic strategy that warrants further investigation.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3816-3816
Author(s):  
Paul Knoebl ◽  
Michael Sasse ◽  
Maria Pia De Carolis ◽  
Jacqueline A Dyck-Jones ◽  
Sandra Ehrle ◽  
...  

Abstract The objective of this non-interventional, international registry was to collect and assess data on the indications, safety, and the outcomes of treatment of patients with acquired protein C deficiency with a plasma-derived, human non-activated protein C concentrate (Ceprotin, Baxalta/Shire). Any patient who received treatment with protein C concentrate was eligible for the study; there were no exclusion criteria. This was an observational study with no required predefined visits, medical or laboratory tests, procedures or interventions either at enrollment or during the study. The study was conducted from June 2010 to June 2015. Management of patients was according to the discretion of the investigator. The primary endpoints were the medical diagnoses associated with protein C concentrate treatment, the protein C concentrate treatment regimens (dose, frequency), treatment outcomes and safety information. Here we report the results from 18 patients with severe acquired protein C deficiency (SAPCD - as judged by the treating physician) from 4 European (EU) investigative sites. Protein C concentrate is not currently approved for treatment of acquired protein C deficiency in the EU. The median age at study entry was 1.9 years (range: birth to 73.1 years); 5 [27.8%] patients were <1 month, 4 (22%) from 1 month to <2 years of age, 2 (11.1%) from 2 to <12 years, 2 (11.1%) from 12 to <18 and 5 (27.8%) ≥18 years of age. Eighteen patients were treated with protein C concentrate. At clinical presentation, 15/18 (83.3%) of these patients had sepsis, 2 had necrotizing enterocolitis and 1 had hemolytic uremic syndrome. Thromboembolic disease was present in 8/18 (25.8%) patients, all of whom had purpura fulminans. Of these 8 patients, 2 had disseminated intravascular coagulation (DIC) in addition to other conditions; 1 patient also had arterial thrombosis, and the other patient had macrovascular thrombosis and skin necrosis. The remaining 10 (74.2%) patients had no evidence of thromboembolic disease: of these, 7 patients had sepsis, 2 necrotizing enterocolitis and 1 hemolytic uremic syndrome. Dose level and frequency were variable: the most common dosage was 100 IU/kg and the most common interval between doses was 6 hours. There were no infusions administered for surgical interventions or for prophylaxis. At the time of final analysis 17/18 (94.4%) of patients had at least one follow-up visit. The median duration of study participation was 17.8 months (range 0.4-39.6 months). The mortality rate was 2/18 (11%) patients, including one case of fatal peritonitis, coinciding with protein C concentrate treatment in a 44 day-old, very low birthweight preterm infant and a case of multi-organ failure in a 19 year-old patient. Both deaths were considered not related to protein C concentrate. Ten patients received anticoagulation therapies in addition to protein C including: 4 treatments with antithrombin concentrates, 1 with clopidogrel, 6 with low molecular weight heparin and 7 with unfractionated heparin. Data from historical protein C concentrate treatments which occurred prior to enrollment in the study were collected from 3 patients upon their enrollment into the study (all 3 treatments resulted in halting/reversal of coagulopathy). During the entire study period, 13 adverse events (AEs) were reported in 5 patients with acquired deficiency; among these, 4 were serious adverse events (SAEs). During the period of treatment with protein C concentrate, there were 2 AEs including an SAE of gastroenteritis; neither were considered related AEs. The results of this registry demonstrate that in current clinical practice in the EU, treatment with protein C concentrate was safe with a mortality rate of 11% in patients with acute SAPCD and thrombotic episodes observed in association with sepsis and/or purpura fulminans in this study. Disclosures Knoebl: Baxalta, now part of Shire: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sasse:Baxter/Baxalta/Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding. De Carolis:Baxalta/Baxter: Other: Baxter Investigator for CEPROTIN Registry. Dyck-Jones:Baxter/Baxalta/Shire: Employment, Equity Ownership. Ehrle:Baxter/Baxalta/Shire: Employment, Equity Ownership. Finnerty:Baxalta/Baxter: Employment. Gelmont:Baxter/Baxalta/Shire: Employment, Equity Ownership. Yel:Baxter/Baxalta/Shire: Employment, Equity Ownership. Loghman-Adham:Baxter/Baxalta/Shire: Employment, Equity Ownership. Fischer:Baxter/Baxalta GmBH: Honoraria, Other: 'Weimarer Sepsis Update 2013'; Baxter/Baxalta GmBH: Consultancy, Other: Co-Authorship for E- Book-Preparing (Importance of the Protein C pathway in coagulation disorders and intensive care medicine / Treatment of congenital and acquired protein C deficiency.


1997 ◽  
Vol 77 (06) ◽  
pp. 1223-1224 ◽  
Author(s):  
Mitsuhiko Sugimoto ◽  
Yoshiyuki Maruhashi ◽  
Atsushi Kobayashi ◽  
Nobuhiro Narita ◽  
Akira Yoshioka

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