scholarly journals CLINICAL APPLICATION OF PLASMA PROTEIN C DETERMINATION

2021 ◽  
Author(s):  
George Zhu ◽  
AW Broekmans ◽  
RM Bertina
Keyword(s):  
Peer Review ◽  
Plasma Protein ◽  
Protein C ◽  
Quantitative Estimation ◽  
Iron Status ◽  
Activated Protein C ◽  
Coagulation Factor ◽  
Protein S ◽  
Healthy Individuals ◽  
Acute Leukemias

 Objective: Protein C, a vitamin K-dependent coagulation factor, is involved in blood coagulation. Activated protein C inactivates Va and VIIIa and stimulates fibrinolysis. In this process, protein S serve as an important factor for activated protein C. Furthermore, excess protein S drives cancer cell proliferation and cell survival through oncogenic receptor Axl(Anexelekto). We determined ranges of protein C both in healthy individuals and distinct hospitalized patients. Methods: A total of 100 patients with different diagnostic diseases and 50 healthy individuals were included in their plasma protein C determination. A rabbit antibody against human protein C was used for the quantitative estimation of plasma protein C antigen by using rocket immunoassay. Results: In healthy individuals protein C antigen (PC:Ag) ranges o.6439- 1.4752 µ/ml. The mean coefficient of variation (CV) of length of rocket was calculated to be 12.45%. PC:Ag within laboratory variation was 11.47%. Plasma protein C antigen was destroyed at 56℃ for 30 minutes, whereas no significant decrease of protein C was found at 4℃ refrigerator for one week. Conclusion:  The results showed that plasma protein C antigen was considerably high in 22 diabetes mellitus. On the other hand, the PC:Ag was significantly decreased in 19 liver cirrhosis(p< 0.001) and was positively correlation with serum albumin levels(p< 0.05). In 20 acute leukemias, on the average,there was slightly lower values in PC:Ag, and accompanied with significant decrease of PC:Ag in 5 M5 subtype and in 9 hyper- leukocytes acute leukemias. However, the 3 acute promyelocytic leukemia (APL) with overt laboratory picture of DIC(disseminated intravascular coagulation) had protein C concentration no lower than the remaining 2 patients with infectious DIC, which suggested the coagulopathy in APL might be due to mechanisms different from other forms of DIC.                     Peer Review History: Received 17 November  2020; Revised 12 Decembe; Accepted 1 January, Available online 15 January 2021 UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file:                           Comments of reviewer(s):         Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewer(s) detail: Dr. Idoko Alexander, Caritas University, Enugu, Nigeria, [email protected] Dr. Rawaa Souhil Al-Kayali, Aleppo University, Syria, [email protected] Similar Articles: THE ASSOCIATION BETWEEN LEVELS OF HEPCIDIN, IRON STATUS AND MICRO-INFLAMMATION MARKERS AMONG HAEMODIALYSIS COUMARIN ANALOGUES AS A POTENTIAL INHIBITOR OF LEISHMANIASIS: A MULTI-TARGETING PROTEIN INHIBITION APPROACH BY MOLECULAR DOCKING VITAMIN A, RETINOIC ACID AND TAMIBAROTENE, A FRONT TOWARD ITS ADVANCES: A REVIEW

Determination of Protein C Antigen Levels in Hospitalized Patients with Blood Coagulative Defects

2021 ◽  
Vol 2 (1) ◽  
pp. 1-04
Author(s):  
George Zhu
Keyword(s):  
Plasma Protein ◽  
Protein C ◽  
Activated Protein C ◽  
Protein S ◽  
Promyelocytic Leukemia ◽  
Hospitalized Patients ◽  
Cancer Cell Proliferation ◽  
Healthy Individuals ◽  
Acute Leukemias

Protein C, a vitamin K-dependent anticoagulant serine protease, is involved in blood coagulation. Activated protein C inactivates Va and VIIIa in purified protein systems and stimulates fibrinolysis by indirectly increasing the level of circulating plasminogen activator. In this process, protein S serve as an important factor for activated protein C. In recent years, excess protein S drives cancer cell proliferation and cell survival through oncogenic receptor Axl (Anexelekto). We determined changes of plasma protein C antigen by using rocket immunoassay both in 50 healthy individuals and 103 distinct hospitalized patients. In healthy individuals protein C antigen(PC:Ag) ranges o.6439- 1.4752 µ/ml. The results showed that plasma protein C antigen was considerably high in 22 diabetes mellitus. In contrast, the PC:Ag was significantly decreased in 19 liver cirrhosis(p< 0.001) and in closely line with serum albumin levels(p< 0.05). In 31 acute leukemias, on the average, there was slightly lower values in PC:Ag, and accompanied with the distribution of significant decrease of PC:Ag values in 5 FAB M5 subtype and in 9 hyperleukocytic leukemias. However, the 3 acute promyelocytic leukemia (APL) with overt laboratory criteria of disseminated intravascular coagulation (DIC) had protein C concentration no lower than the remaining 2 patients with infectious DIC, which suggested the coagulopathy in APL might be due to mechanisms different from other forms of DIC.

scholarly journals Increased prothrombin activation in protein S-deficient plasma under flow conditions on endothelial cell matrix: an independent anticoagulant function of protein S in plasma

Blood ◽  
1995 ◽  
Vol 85 (7) ◽  
pp. 1815-1821 ◽  
Author(s):  
C van't Veer ◽  
TM Hackeng ◽  
D Biesbroeck ◽  
JJ Sixma ◽  
BN Bouma
Keyword(s):  
Endothelial Cell ◽  
Tissue Factor ◽  
Protein C ◽  
Activated Protein C ◽  
Coagulation Factor ◽  
Protein S ◽  
Flow Conditions ◽  
Cell Matrix ◽  
Anticoagulant Function ◽  
Prothrombin Activation

Protein S is a vitamin K-dependent nonenzymatic coagulation factor involved in the regulation of activated protein C (aPC). In this study, we report an aPC-independent anticoagulant function of protein S in plasma under flow conditions. Plasma, anticoagulated with low-molecular-weight heparin allowing tissue factor-dependent prothrombin activation, was perfused at a wall shear rate of 100 s-1 over tissue factor containing matrices of stimulated endothelial cells placed in a perfusion chamber. Fractions were collected in time at the outlet and prothrombin activation was determined by measuring the activation fragment F1+2 of prothrombin. In normal plasma, a time-dependent prothrombin activation was detected by the generation of fragment1+2. Prothrombin activation had ceased after 12 minutes perfusion, independent of the amount of tissue factor present in the matrix. Depletion of protein S from plasma or inhibition of protein S in plasma by monoclonal antibodies induced a 5- to 25-fold increase of prothrombin activation on the procoagulant endothelial cell matrix. A prolonged prothrombin activation was detected in protein S-depleted plasma up to 20 minutes after onset of the thrombin generation. The increased prothrombin activation in protein S-depleted plasma could not be explained by the absence of the cofactor function of protein S for aPC because depletion of protein C from plasma did not result in increased prothrombin activation. These data provide further evidence for a strong anticoagulant function of protein S in plasma independent from activated protein C.

The anticoagulant function of coagulation factor V

2012 ◽  
Vol 107 (01) ◽  
pp. 15-21 ◽  
Author(s):  
Thomas J. Cramer ◽  
Andrew J. Gale
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Coagulation Factor ◽  
Protein S ◽  
Factor V ◽  
Phospholipid Membrane ◽  
Terminal Part ◽  
Coagulation Factor V ◽  
Cofactor Activity ◽  
Anticoagulant Function

SummaryAlmost two decades ago an anticoagulant function of factor V (FV) was discovered, as an anticoagulant cofactor for activated protein C (APC). A natural mutant of FV in which the R506 inactivation site was mutated to Gln (FVLeiden) was inactivated slower by APC, but also could not function as anticoagulant cofactor for APC in the inactivation of activated factor VIII (FVIIIa). This mutation is prevalent in populations of Caucasian descent, and increases the chance of thrombotic events in carriers. Characterisation of the FV anticoagulant effect has elucidated multiple properties of the anticoagulant function of FV: 1) Cleavage of FV at position 506 by APC is required for anticoagulant function. 2) The C-terminal part of the FV B domain is required and the B domain must have an intact connection with the A3 domain of FV. 3) FV must be bound to a negatively charged phospholipid membrane. 4) Protein S also needs to be present. 5) FV acts as a cofactor for inactivation of both FVa and FVIIIa. 6) The prothrombotic function of FVLeiden is a function of both reduced APC cofactor activity and resistance of FVa to APC inactivation. However, detailed structural and mechanistic properties remain to be further explored.

Protein S Released From Stimulated Platelets Has Anticoagulant Activity Independent of Activated Protein C and Tissue Factor Pathway Inhibitor (TFPI).

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1137-1137
Author(s):  
Mary J. Heeb ◽  
Erning Duan
Keyword(s):  
Plasma Protein ◽  
Neutralizing Antibodies ◽  
Protein C ◽  
Thrombin Generation ◽  
Conflicts Of Interest ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Protein S ◽  
Platelet Protein ◽  
Presence And Absence

Abstract Abstract 1137 Background: Platelets contain in their alpha granules ∼2.5% of the protein S in blood. It has been suggested that this protein S supports the anticoagulant activity of exogenous activated protein C (APC), but it is not known whether protein S that is released from stimulated platelets can exert anticoagulant activity that is independent of APC and TFPI. We recently showed that at least some of the anticoagulant activity of plasma protein S is independent of APC and TFPI, although data suggested that plasma protein S may also have TFPI-dependent activity. Objective and methods: To determine if platelet protein S has anticoagulant activity that is independent of APC and TFPI, prothrombinase and extrinsic FXase reactions were initiated on the surface of fresh stimulated or unstimulated washed platelets in the presence and absence of blocking antibodies against APC, TFPI, and/or protein S, or in the presence and absence of purified plasma-derived protein S. Platelets were adjusted to a concentration of 0.7 to 2 × 10e8/ml, which contained 2.3–6.5 nM total platelet protein S. The last platelet wash contained negligible amounts of plasma protein S. Results: Neutralizing anti-protein S antibodies allowed up to 5.7-fold (mean: 2.1 ± 1.5 –fold, n=13) more thrombin generation on calcium ionophore-stimulated platelets following supplementation with 50–500 pM FXa and 600 nM prothrombin, and allowed up to 2.5-fold (mean: 1.7 ± 0.7 –fold, n=11) more thrombin generation on platelets that were not ionophore-stimulated but were gradually stimulated following FXa and prothrombin supplementation. Anti-protein S antibodies had no effect on thrombin generation on platelets that were treated with prostaglandin E1 (PGE1) to suppress platelet activation and then supplemented with procoagulants. This implies that platelet protein S is released from stimulated platelets and downregulates thrombin generation on platelets, and that neutralizing anti-protein S antibodies block this activity of protein S. Anti-protein S antibodies allowed up to 1.8-fold (mean 1.5 ± 0.2 –fold, n=8) more FXa generation on the surface of stimulated platelets supplemented with 5 pM TF, 100 pM FVIIa, and 160 nM FX, but anti-protein S antibodies had no effect on FXa generation on platelets treated with PGE1. Most of these experiments were performed in the presence of neutralizing antibodies against TFPI and APC, but thrombin and FXa generation on platelets under the varying conditions described were unaffected by the presence of these neutralizing antibodies. Purified plasma-derived zinc-containing protein S downregulated thrombin and FXa generation on platelets (IC50 = 6–18 nM PS) and in plasma >10-fold more potently than zinc-deficient protein S. We could not demonstrate a synergistic anticoagulant effect when TFPI was combined with zinc-deficient protein S in the presence of stimulated platelets and procoagulant proteins. Conclusion: Protein S that is released from stimulated platelets exerts anticoagulant activity that is independent of TFPI and APC. Disclosures: No relevant conflicts of interest to declare.

Defects in the protein C pathway

1987 ◽  
Author(s):  
P C Comp ◽  
C T Esmon
Keyword(s):  
Plasminogen Activator ◽  
Plasma Protein ◽  
Skin Necrosis ◽  
Protein C ◽  
Binding Protein ◽  
Active Form ◽  
Activated Protein C ◽  
Protein S ◽  
Receptor Protein ◽  
Protein C Deficiency

Activated protein C functions as an anticoagulant by enzymatically degrading factors Va and Villa in the clotting cascade. Protein C may be converted to its enzymatically active form bythrombin. The rate at which thrombin cleavage of the zymogen occurs is greatly enhanced when thrombin is bound to an endothelial cell receptor protein, thrombomodulin. Activated proteinC has a relatively long half-life in vivo and the formation of activated protein C in response to low level thrombin infusion suggests that the protein C system may provide a feedback mechanism to limit blood clotting. Clinical support for such a physiologic role for activated protein C includes an increased incidence of thrombophlebitis and pulmonary emboli in heterozygous deficient individuals, and severe, often fatal, cutaneous thrombosis in homozygous deficient newborns. A third thrombotic condition associated with protein C deficiency is coumarin induced skin (tissue) necrosis. This localized skin necrosis occurs shortly after the initiation of coumarin therapy and is hypothesized to bedue to the rapid disappearance of protein C activity in the plasma beforean adequate intensity of anticoagulation is achieved. Recent estimates of heterozygous protein C deficiency range as high as 1 in 300 individuals in the general population. Since coumarin compounds are in routine clinical use throughout the world and skin necrosis remains a relatively rare clinical finding, this suggests that factors other than protein C deficiency alone may be involved in the pathogenesis of the skin necrosis.The anticoagulant properties of activated protein C are greatly enhanced by another vitamin K-dependent plasma protein, protein S. Protein S functions by increasing the affinity of activated protein C for cell surfaces.Protein S is found in two forms in plasma: free and in complex with C4b-binding protein, "an inhibitor of the complement system. Free protein S is functionally active and the complexed protein S is not active. Individuals congenitally deficient in protein S ae subject to recurrent thromboembolicevents. At least two classes of protin S deficiency occur.Some patienshavedecreased levels of protein S antigen and reduced protein S functional activity. A second group of deficient individuals have normal levels of protein S antigen but most or all their protein S is complexed to C4b-binding protein and they have little or no functional protein S activity. Such a protein S distribution could result from abnormal forms of protein S or C4b-binding protein or some other abnormal plasma or cellular component. Patients with functionally inactive forms of protein S have yet to be identified. Identification of protein S deficient individuals is complicated by thepossible effect of sex hormones on plasma protein S levels. Total protein S antigen is reduced during pregnancyand during oral contraceptive administration. This finding is of practicalclinical importance since the decrease in protein S which occurs during pregnancy may be an added risk factor for congenitally protein S deficient women and may explain why some proteinS deficient women experience their first episode of thrombosis during pregnancy.In addition to having anticoagulant properties, activated protein C enhances fibrinolysis, at least in part,by inhibiting the inhibitor of tissueplasminogen activator. This profibrinolytic effect is enhanced by protein S and cell surfaces. This protection of plasminogen activator activity suggests that the combination of tissue plasminogen activator and activated protein C may be useful in the treatment of coronary artery thrombi. Tissueplasminogen activator would promote clot lysis while activated protein C protected the plasminogen activatorfrom inhibition and also prevented further clot deposition. There is no evidence at present that fibrinolytic activity is reduced in protein C deficient individuals. The possible clinical relevance of this aspect of protein Cfunction in the predisposition of protein C deficient individuals to thrombosis remains to be defined.

Protein S levels modulate the activated protein C resistance phenotype induced by elevated prothrombin levels

2006 ◽  
Vol 95 (02) ◽  
pp. 236-242 ◽  
Author(s):  
Jeroen Brugge ◽  
Guido Tans ◽  
Jan Rosing ◽  
Elisabetta Castoldi
Keyword(s):  
Protein C ◽  
Thrombin Generation ◽  
Activated Protein C ◽  
Protein S ◽  
Healthy Individuals ◽  
Resistance Phenotype ◽  
Apc Resistance ◽  
Thrombosis Risk ◽  
Highly Correlated

SummaryElevated plasma prothrombin levels, due to the prothrombin 20210 G/A mutation or to acquired causes, area risk factor for venous thrombosis,partly because of prothrombin-mediated inhibition of the protein C anticoagulant pathway and consequent activated proteinC (APC) resistance. We determined the effect of plasma prothrombin concentration on the APC resistance phenotype and evaluated the role of protein S levels asa modulating variable. The effect of prothrombin and protein S levels on APC resistance was investigated in reconstituted plasma systems and in a population of healthy individuals using both the aPTT-based and the thrombin generation-based APC resistance tests. In reconstituted plasma, APC resistance increased at increasing prothrombin concentration in both assays. Enhanced APC resistance was caused by the effect of prothrombin on the clotting time in the absence of APC in the aPTT-based test, and on thrombin formation in the presence of APC in the thrombin generation-based test. In plasma from healthy individuals prothrombin levels were highly correlated to protein S levels. Since prothrombin and proteinS had opposite effects on the APC resistance phenotype, the prothrombin/protein S ratio was a better predictor of APC resistance than the levels of either protein alone. Prothrombin titrations in plasmas containing different amounts of proteinS confirmed that proteinS levels modulate the ability of prothrombin to induce APC resistance. These findings suggest that carriers of the prothrombin 20210 G/A mutation, who have a high prothrombin/protein S ratio, may experience a higher thrombosis risk than non-carriers with comparable prothrombin levels.

Low levels of plasma protein S, protein C and coagulation factor XII during early pregnancy and adverse pregnancy outcome

2015 ◽  
Vol 114 (07) ◽  
pp. 65-69 ◽  
Author(s):  
Yasuhiko Ebina ◽  
Masahiro Ieko ◽  
Sumiyoshi Naito ◽  
Gen Kobashi ◽  
Masashi Deguchi ◽  
...  
Keyword(s):  
Risk Factors ◽  
Plasma Protein ◽  
Early Pregnancy ◽  
Protein C ◽  
Coagulation Factor ◽  
Protein S ◽  
Factor Xii ◽  
Independent Risk Factors ◽  
Low Levels ◽  
Adverse Pregnancy

SummaryIt was the study objective to evaluate whether low levels of plasma protein S (PS) activity, free PS, protein C (PC) activity and coagulation factor XII (FXII) during early pregnancy are related to adverse pregnancy outcomes. Peripheral blood samples were obtained at 8–14 gestational weeks (GW) from a consecutive series of 1,220 women. The levels of plasma PS activity, free PS, PC activity, and FXII were measured. Cut-off values were defined as < 1st, < 5th, and < 10th percentiles of values obtained from 933 women whose pregnancies ended in normal deliveries without complications. PS activity of < 10th percentile yielded risks of pregnancy-induced hypertension (PIH) and severe PIH, while free PS level of < 5th percentile yielded a risk of preeclampsia. FXII level of < 1st percentile yielded a risk of premature delivery (PD) at < 34 GW. None was associated with PD at < 37 GW, fetal growth restriction or fetal loss. A multivariate analysis demonstrated that PS activity of < 10th percentile (odds ratio 5.9, 95 % confidence interval 1.7–18.1) and body mass index (BMI) ≥ 25 kg/m2 (4.3, 1.1–13.3) were independent risk factors for severe PIH. Similarly, free PS level of < 5th percentile (4.4, 1.0–14.3) and BMI ≥ 25 kg/m2 (4.0, 1.3–10.9) were independent risk factors for pre-eclampsia. In conclusion, women with low levels of plasma PS activity and free PS during early pregnancy might have increased risks of PIH, severe PIH or pre-eclampsia. Women with low FXII level might have an increased risk of PD at < 34 GW.

Comparison of Activated Protein C Resistance With Factor V Leiden Testing by Molecular Assay

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S5-S5
Author(s):  
William R Perry ◽  
Steven W Pipe ◽  
Shih-Hon Li
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Coagulation Factor ◽  
Protein S ◽  
European Ancestry ◽  
Variant Form ◽  
Factor V ◽  
Low Protein ◽  
Protein C Activity

Abstract Factor V Leiden (FVL) is a variant form of coagulation factor V that is the most common inherited risk factor for venous thromboembolism in people of European ancestry. FVL is associated with the missense mutation, p.R506Q, which encodes a FV protein resistant to cleavage by activated protein C (APC). Laboratory testing for FVL includes both phenotypic assays that assess APC resistance (APCR) and molecular assays that evaluate FVL genotype (FVLM) directly. Although APCR results are typically highly concordant with FVL genotype, discrepancies are known to occur and may result in inference of an incorrect FV genotype if only APCR testing is used. The objective of this study was to compare the results of these two testing methodologies and to identify potential explanations for discrepancies in results. Data were obtained by searching the electronic medical record of a large academic hospital for patients who underwent both APCR and FVLM testing from 2013 to 2018. APCR was evaluated using the ratio between two dilute Russell Viper Venom Time (DRVVT) tests, one preincubated with a protein C activator derived from A contortrix contortrix venom and the other with vehicle; the validated normal APCR ratio is ≥1.7. FVLM was performed by invader analysis utilizing fluorescence resonance energy transfer (FRET). In total, 424 patients underwent testing with both assays. Of 21 patients who had APCR assay clot times that exceeded the measurement range, all were FVLM negative, and 15 were anticoagulated during APCR testing. Of the 403 patients with reportable results for both tests, 385 (95.5%) patients had normal APCR and were FVLM negative. Of the 18 (4.5%) patients with discrepant results, 15 (3.7%) had an abnormally low APCR but were FVLM negative, and 3 (0.8%) had a normal APCR but were FVLM heterozygous. Among the 15 FVLM-negative patients with abnormal APCR <1.7, 11 (73.3%) were on warfarin with/out enoxaparin and had low protein S activity and/or low protein C activity. Of the 3 FVLM heterozygous patients with normal APCR, 1 was on apixaban. Our results demonstrated a high concordance between APCR phenotype and FVLM genotype. The concordance of APCR and FVLM may be limited in patients with low protein S or low protein C activity and those on a range of anticoagulant therapy.

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