Use of protein C concentrate in neonatal period

Levels of protein C, low at birth, physiologically Increase until six months of age and achieve the adult range after puberty. Protein C deficiency may be congenital or acquired. Severe protein C deficiency is a rare autosomal recessive disorder that usually presents in neonatal period with purpura fulminans. Acquired protein C deficiency may be caused by increased consumption (e.g., asphyxia, overt DIC, severe infection without overt DIC, acute VTE) or by decreased synthesis of the active carboxylated protein (e.g. administration of vitamin K antagonists, severe hepatic synthetic disfunction). Two different formulations of protein C are available: recombinant human activated protein C (rhAPC) and human plasma-derived viral-inactivated protein C. It is known that in septic patients replacement therapy with rhAPC reduces mortality but is associated with an increased risk of bleeding. During the neonatal period, when a higher risk of bleeding exists, the human plasma-derived viral-inactivated protein C concentrate may represent an effective therapeutic option. In fact, its administration results effective both in severe congenital and acquired forms of protein C deficiency.

Hereditary protein C deficiency caused by the Ala267Thr mutation in the protein C gene is associated with symptomatic and asymptomatic venous thrombosis

INTRODUCTION

Protein C (PC) is a key anticoagulant that regulates hemostasis, and inherited deficiency of PC is an established risk factor for venous thrombosis (VT). The factor V Leiden mutation causing activated PC (APC) resistance is an additional risk factor for VT. Reduced PC levels in the circulation and/or APC resistance do not necessarily lead to thrombotic disease. In the present study we describe and characterize an ethnic Lebanese family in which individuals with reduced PC levels and APC resistance have various clinical symptoms.

METHODS

PC activity and antigen levels and APC resistance in the family members were quantified with commercial kits. Sequencing of PC DNA and mRNA was performed with BigDye Terminator Cycle Sequencing kit on the ABI 3730 Genetic Analyzer.

RESULTS

PC antigen and anticoagulant activity in the plasma of the proband and family members ranged from 9% to 69% and 3% to 63%, respectively, compared to levels measured in pooled normal plasma. Sequencing analysis of the PC gene of family members revealed that they were either homozygous or heterozygous for the Ala267Thr mutation. In addition, three of them exhibited APC resistance. None of the family members, except the proband, have had a history of VT despite that two of them have two genetic risk factors for thrombosis.

High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin

Hereditary deficiencies of protein S, protein C and antithrombin are known risk factors for first venous thromboembolism. We assessed the absolute risk of recurrence, and the contribution of concomitant thrombophilic defects in a large cohort of families with these deficiencies. Annual incidence of recurrence was estimated in 130 deficient patients, with separate estimates for those with each of protein S, protein C, and antithrombin deficiency, and in eight non-deficient patients with prior venous thromboembolism. All patients were also tested for factor V Leiden, prothrombin G20210A, high levels of factors VIII, IX and XI, and hyperhomocysteinemia. There were 81 recurrent events among 130 deficient patients. Median follow-up was 4.6 years. Annual incidences (95% confidence interval) of recurrent venous thromboembolism were 8.4% (5.8-11.7) for protein S deficiency, 6.0% (3.9-8.7) for protein C deficiency, 10.0% (6.1-15.4) for antithrombin deficiency, and overall 7.7% (6.1-9.5). Relative risk of recurrence in patients with a spontaneous versus provoked first event was 1.5 (0.95-2.3). Cumulative recurrence rates at 1, 5 and 10 years were 15%, 38% and 53%. Relative risk of recurrence with concomitant defects was 1.4 (0.7-2.6) (1 defect) and 1.4 (0.8-2.7) (> or =2 defects). Annual incidence was 1.0% (0.03-5.5) in eight non-deficient patients. Annual incidence of major bleeding in deficient patients on oral anticoagulant treatment was 0.5% (0.2-1.0). We conclude that patients with a hereditary protein S, protein C or antithrombin deficiency appear to have a high absolute risk of recurrence. This risk is increased after a first spontaneous event, and by concomitance of other thrombophilic defects.

[Cerebral sinovenous thrombosis and acquired antithrombin, protein C and S deficiency during chemotherapy in a young man: report of a case]

L-asparaginase is commonly used in the chemotherapy regimens for acute lymphoblastic leukaemia. Its use is associated with thrombotic complications in 1 to 14 % of the cases. The pathogenesis of this complication is still unclear. However, the decrease of antithrombin seems to play an important role. We report a case of a 17-year old man with a acute lymphoblastic leukaemia, who developed a cerebral sinovenous thrombosis due to an acquired deficiency of antithrombin and protein C and S following L-asparaginase chemotherapy. We discuss the use of prophylactic supplements of antithrombin and the value of screening of thrombophilia based on the recent medical literature.

Mesenteric vein thrombosis associated with primary cytomegalovirus infection: a case report

In the past few years several studies have supported an interplay between cytomegalovirus infections and a prothrombotic state. We describe a case of primary cytomegalovirus infection in an immunocompetent adult that was complicated with mesenteric vein thrombosis. Transient protein C deficiency, lupus anticoagulant and activated protein C resistance were found, in combination with a heterozygous prothrombin G20210A mutation. We discuss the possible mechanisms of cytomegalovirus-related venous thrombosis.

Exclusion of the alpha2 subunit of platelet-activating factor acetylhydrolase 1b (PAFAH1B2) as a prothrombotic gene in a protein C-deficient kindred and population-based case-control sample

Protein C deficiency increases the risk of venous thromboembolic disease among members of Kindred Vermont II, but fails to fully account for the inheritance pattern. A genome scan of the pedigree supported the presence of a prothrombotic gene on chromosome 11q23 (107-119 Mb, nominal P < 0.0001), with weaker support on chromosomes 10p12 (11-25 Mb, P < 0.0003) and 18p11.2-q11 (12-24 Mb, P < 0.0007). The 11q23 region contains the alpha(2) subunit (gene name PAFAH1B2) of platelet-activating factor acetylhydrolase 1b, a candidate prothrombotic gene. Re-sequencing of the PAFAH1B2 regulatory region in 137 pedigree members, including 25 thrombosis cases, revealed 12 variants; eight were present in only 0-2 affected individuals; the other four assorted into three haplotypes and included three variants predicted to destroy transcription factor-binding sites. More extensive re-sequencing of the PAFAH1B2 gene in 11 affected and five unaffected pedigree members revealed an additional 13 variants that assorted into the same three haplotypes. We rejected as thrombosis risk factors each of the three presumed destructive variants as well as each of the three haplotypes. We also rejected (odds ratio = 1.31 CI: 0.91-1.88) one of the three variants in 469 cases and 472 controls from the Leiden Thrombophilia Study (LETS). Therefore, PAFAH1B2 is not the gene responsible for the linkage evidence on chromosome 11q23.

Hirudin treatment for multiple thromboses in a preterm infant with inherited thrombophilia

Thromboembolic events in preterm infants constitute a serious problem in neonatal intensive care. In most cases, treatment with low-molecular-weight heparin offers a sufficient therapy of thrombotic events. We report the case of a severely sick male preterm infant with a heterozygous factor V Leiden mutation and protein C deficiency. The infant developed multiple thromboses despite adequate anticoagulation with enoxaparin and was in a life-threatening situation. Treatment with hirudin prevented the occurrence of new thromboses without causing bleeding complications. After 2 weeks hirudin was discontinued and low-molecular-weight heparin therapy was started again. A successive recanalization of the vast majority of affected vessels was observed within the following 6 months. Despite some minor neurologic sequelae and a slight delay in neuro-motor development, the 2.5-year-old boy is in a healthy condition. This case demonstrates that hirudin can be an effective alternative anticoagulant in neonates and infants refractory to heparin treatment. Efficacy and safety issues of hirudin treatment, however, need to be evaluated in randomized trials.

[Molecular mechanisms of protein C deficiency caused by C64W and F139V mutations]

OBJECTIVE

To study the molecular mechanisms of protein C (PC) deficiency caused by PC gene mutations of C64W, F139V and K150 deletion (K150d).

METHODS

Wild-type and mutant PC cDNA expression plasmids (PCwt, PC C64W, PC F139V, PC K150d) were constructed and transfected into COS-7 cells or CHO cells respectively for in vitro expression study and immunofluorescent assay. Fluorescent real-time PCR was used to detect the expression of PC mRNA, protein degradation inhibition and endo-beta-N-acetylglucosaminidase H (Endo H) digestion experiments to explain the mutant protein degradation pathway and its localizations inside the cells.

RESULTS

PC C64W was not secreted from the cells and was gradually degraded inside the cells. There was partial secretion of PC F139V, most of the protein molecule was not secreted and degraded intracellularly. Mutant PC K150d was secreted normally from the cells. Fluorescent realtime PCR analysis of total mRNA from transfected cells showed no reduction of the mutant PC mRNA expression compared with that of wild-type PC mRNA. Protein degradation inhibition experiments showed that mutants PC C64W and PC F139V were degraded intracellularly through the proteasome pathway. Endo H digestion experiments and immunofluorescence results suggested that mutant PC molecules were located mainly in pre-Golgi apparatus.

CONCLUSIONS

Impaired secretion and degradation intracellularly of the mutants might be the molecular mechanisms of PC deficiency caused by C64W and F139V mutations. K150 deletion mutation might not affect the secretion of the mutant.

[Analysis of phenotype and genotype in two Chinese pedigrees with hereditary protein C deficiency]

OBJECTIVE

To identify the phenotype and gene mutation in two Chinese pedigrees with hereditary protein C deficiency.

METHODS

The plasma level of protein C activity (PC: A) , protein C antigen (PC: Ag), protein S activity (PS: A), and antithrombin activity (AT: A) of the probands and their family members were detected using chromogenic assay and ELISA, respectively. All of the nine exons and intron-exon boundaries of protein C gene were amplified by PCR and analyzed by direct sequencing of the probands. Restriction enzyme site analysis was used to confirm the mutation.

RESULTS

The plasma PC: A and PC: Ag for proband 1 was 1.2% and 0, respectively. Compound heterozygous mutations, C(TGC)64W (TGG) and F(TTC) 139V(GTC) , were identified in her, the former being inherited from the maternal side and the later the paternal side. Further genetic analysis showed that her husband ( II 8) had the heterozygous deletion mutation (K150 or 151 Del) in exon 7, her daughter had the same heterozygous deletion mutation and a F139V. The plasma PC: A and PC: Ag for proband 2 was 50. 3% and 1.9 mg/L, respectively. He had the heterozygous Lys150 or Lys151 deletion mutation, which was inherited from his father. Polymorphisms of C/T at position - 1654, A/G at - 1641 , and A/T at - 1476A/T in the promoter region of protein C were confirmed in all members of the two pedigrees, of which, proband 2 had homozygous CC/GG/TT. The F139V mutation was confirmed by restriction enzyme site analysis and polymorphism for this mutation was excluded. PS: A and AT: A were in normal range for all members.

CONCLUSION

Compound heterozygous mutation C64W and F139V of protein C gene lead to type I hereditary protein C deficiency for proband 1. K150 or 151 deletion mutation and polymorphism of CC/GG/TT might lead to type I hereditary protein C deficiency for proband 2. C64W is a novel mutation for protein C gene. F139V and K150 or 151 deletion mutation are reported for the first time in China.

[Thyroid crisis and protein C deficiency in a case of superior sagittal sinus thrombosis]

We report the case of a 28-year-old woman who presented simultaneously with superior sagittal sinus thrombosis and thyroid crisis, and was subsequently found to have protein C deficiency. February 3, 2003, she admitted complaining of abdominal pain. The diagnosis of appendicitis was made, and she was operated on under lumbar anaesthesia. Day 7, she developed acute headache and distal weakness of the left lower limb. On examination she was alert, with a temperature of 38 degrees C, a sinus tachycardia of 124/min and blood pressure 164/84 mmHg. Neurological examination revealed neck stiffness and left hemiparesis, predominantly in her lower limb. Gadlinium-enhanced brain MRI revealed extensive superior sagittal sinus thrombosis. CT scan demonstrated infarction in the right frontal cortex, and subarachnoid hemorrhage adjacent to the right cerebellar tentorium. The patient was treated with a free radical scavenger edarabon, and glycerin. No anticoagulant therapy was instituted. Over the next 24 hours, her condition worsened. She became comatose, as well as developing a generalized tonic-clonic seizure. Day 12, laboratory examinations revealed an undetectable TSH-level CTSH (thyroid stimulating hormone) <0.005 mcIU/ml), with a level of free thyroxin 7.77 ng/dl (0.9-1.7), free triiodothyronin 29.6 pg/ml (2.3-4.3), and positive anti-TSH receptor antibodies determined subsequently. Coagulation factor VIII activity was 155% (normal range 60-150). Protein C deficiency (antigen 59%, activity 49%) was also present, suggesting a congenital type I heterozygous deficiency. A diagnosis of thyroid crisis on the basis of Graves' disease was made. The patient remained comatose and died on Day 16, with renal failure. The patient had protein C deficiency, a well-established risk factor for cerebral venous thrombosis (CVT). However, additional risk factors are required in most cases to precipitate CVT. In our case, this trigger was most likely thyroid crisis, suggesting that thyrotoxicosis, probably through hypercoagulability, may be a predisposing factor for the development of CVT.

[Inherited thrombophilia and arterial diseases]

Thrombophilia may be defined as an acquired or congenital abnormality of hemostasis predisposing to thrombosis. Some of the inherited abnormalities such as factor V Leiden mutation, factor II G20210A mutation as well as deficiencies in antithrombin, protein C and protein S, are already known to be risk factors for venous thromboembolism. This review focuses on the link between these abnormalities and arterial thrombosis. Routine screening for these disorders is not indicated in most cases of arterial complications, but could be useful in some sub-groups of patients, such as young patients, smokers, patients on oral contraception, or those with premature occlusion after revascularization procedures. Anticoagulation rather than antiplatelet therapy may be preferable for these patients.

Type II protein C deficiency in a 16-year-old girl with central retinal vein occlusion

PURPOSE

To report a case of central retinal vein occlusion in the setting of type II protein C deficiency, and to describe the appropriate tests for detecting this clotting abnormality.

DESIGN

Observational case report.

METHODS

Retrospective review of clinical examination and laboratory findings.

RESULTS

A 16-year-old girl was evaluated for progressive monocular vision loss occurring over a period of one month. Dilated fundus examination and fluorescein angiography revealed the presence of a central retinal vein occlusion. Hypercoagulable work-up demonstrated normal protein C antigen levels, but a marked reduction in protein C function, confirming a type II protein C deficiency.

CONCLUSIONS

Central retinal vein occlusion may be associated with type II protein C deficiency. Testing for protein C antigen levels and function is necessary for detection of both type I and type II protein C deficiency.

Negative pressure dressing for promoting wound healing of purpura fulminans in a newborn with homozygous protein C deficiency

A negative pressure dressing to promote wound healing of purpura fulminans in a girl aged 35 days with homozygous protein C deficiency is reported. Two wounds of 11 x 11 cm2 at the abdominal wall and 14 x 14 cm2 at the left trunk were covered with sterile sponges embedded with a multiple-hole drain tube and transparent plastic film. The exposed end of the drain was then connected to the wall suction apparatus to create negative pressure at -120 mmHg. The dressing was changed every 2 days. Within 4-6 weeks, the wounds were completely healed and skin grafting was not required.

Protein C deficiency in a family with thromboembolism and identified gene mutations

Protein C is the central component of the major anti-thrombotic regulatory system, and individuals with hereditary protein C deficiency tend to have an increased risk of thromboembolism. During the last several years, mutations causing protein C deficiency have been identified. In the present study, we report familial cases with three nucleotide substitutions: One is a missense mutation Arg169Trp, which was previously reported. The other two are C-154T promoter polymorphism (rs1799808 on dbSNP database), the function of which is unknown and Ser99Ser synonymous polymorphism (rs5936). All three mutations were found in a 24-year-old patient with pulmonary thromboembolism and his 54-year-old father who also had pulmonary thromboembolism. C-154T promoter polymorphism (rs1799808 on dbSNP database) and Ser99Ser synonymous polymorphism (rs5936) were found in the patient's mother.

Acute inflammation is exacerbated in mice genetically predisposed to a severe protein C deficiency

The anticoagulant, activated protein C (aPC), possesses antithrombotic, profibrinolytic, anti-inflammatory, and antiapoptotic properties, and the level of this protein is an important marker of acute inflammatory responses. Although infusion of aPC improves survival in a subset of patients with severe sepsis, evidence as to how aPC decreases mortality in these cases is limited. Because a total deficiency of PC shows complete neonatal lethality, no animal model currently exists to address the mechanistic relationships between very low endogenous aPC levels and inflammatory diseases. Here, we show for the first time that novel genetic dosing of PC strongly correlates with survival outcomes following endotoxin (LPS) challenge in mice. The data provide evidence that very low endogenous levels of PC predispose mice to early-onset disseminated intravascular coagulation, thrombocytopenia, hypotension, organ damage, and reduced survival after LPS challenge. Furthermore, evidence of an exacerbated inflammatory response is observed in very low PC mice but is greatly reduced in wild-type cohorts. Reconstitution of low-PC mice with recombinant human aPC improves hypotension and extends survival after LPS challenge. This study directly links host endogenous levels of PC with various coagulation, inflammation, and hemodynamic end points following a severe acute inflammatory challenge.

The relationship between pregnancy induced hypertension and congenital thrombophilia

OBJECTIVE

To investigate the relationship between some thrombophilic parameters and pregnancy induced hypertension (PIH).

METHODS

The study took place at the Department of Obstetrics and Gynecology, Perinatology Unit, Faculty of Medicine, Cukurova University, Turkey, between January 2002 and December 2002. We evaluated 202 patients. Patients were divided into 2 groups: control group comprised 102 normotensive patients >20 weeks of pregnancy without any medical or pregnancy related pathologies and the study group comprised 100 patients over 20 weeks of pregnancy with PIH. These hypertensive patients were divided into 6 sub-groups as follows: eclampsia, severe preeclampsia, preeclampsia, chronic hypertension plus superimposed preeclampsia, eclampsia, and hemolysis elevated liver enzymes and thrombocytopenia (HELLP) syndrome.

RESULTS

In all cases, complete blood count, antithrombin III, protein S levels, factor V Leiden mutation, prothrombin 20210 mutation, methylenetetrahydrofolate reductase (MTHFR) 677 mutation and homocysteine levels were studied. Statistical analysis of the data was carried out using SPSS version 11.0 program. In comparing the 2 groups we used Mann-Whitney U tests. In comparing the PIH subgroups we used Kruskal-Wallis tests. The levels of p<0.05 were accepted as statistically significant.

CONCLUSION

Antithrombin III deficiency, protein C deficiency, hyperhomocysteinanemia were found to be associated with PIH groups. But protein S deficiency, and homozygote factor V Leiden mutation, prothrombin 20210, MTHFR 677 mutation were not found to be related with PIH.

Management of neonatal purpura fulminans with severe protein C deficiency

Neonatal purpura fulminans is a life threatening clinical entity characterized by extensive subcutaneous thrombosis and disseminated intravascular coagulation usually manifesting shortly after birth. We report an autosomal recessive form of the disease in a neonate who was diagnosed with compound heterozygosity for mutations in his protein C gene as the molecular basis of his disorder.