-
American Journal of Veterinary Research Jul 2023To establish normal values for pre- and post-prandial bile acids and protein C in Pacific harbor seal (Phoca vitulina richardsi) pups.
OBJECTIVE
To establish normal values for pre- and post-prandial bile acids and protein C in Pacific harbor seal (Phoca vitulina richardsi) pups.
ANIMALS
45 harbor seals undergoing rehabilitation at the Vancouver Aquarium Marine Mammal Rescue Centre, 0 to 16 weeks, and deemed healthy aside from malnutrition or maternal separation.
PROCEDURES
Venous blood was collected from the intervertebral extradural sinus in fasted seals and again 2 hours after a fish meal.
RESULTS
The reference interval (90% CL, confidence limit) for pre-prandial (fasting) bile acids was 17.2 μmol/L to 25.4 μmol/L, post-prandial bile acids were 36.9 μmol/L to 46.4 μmol/L, and protein C was 72.3% to 85.4%, across ages. For comparison between developmental ages, pups were grouped into 3 age classes: < 14 days, 5 to 8 weeks, and 10 to 16 weeks. Age affected pre- and post-prandial bile acids; pups < 14 days had significantly higher pre-prandial bile acids (36.0 μmol/L ± 16.5 μmol/L; P < .0001) than other age groups and pups 5 to 8 weeks had significantly higher post-prandial bile acids (50.4 μmol/L ± 21.9 μmol/L; P < .001). Protein C was also affected by age, with seals < 14 days having significantly lower values (mean, 51.8% ± 16.7%; P < .0001).
CLINICAL RELEVANCE
This study established normal reference intervals for bile acids in harbor seal pups and offered a preliminary investigation into protein C in pinnipeds. The bile acid values from 0- to 16-week-old seal pups were well above established normal ranges for domestic species, highlighting the utility of age- and species-specific reference ranges. The values presented here and the differences across age classes will aid clinicians in accurately diagnosing hepatobiliary disease in harbor seal pups.
Topics: Animals; Phoca; Protein C; Maternal Deprivation
PubMed: 37187459
DOI: 10.2460/ajvr.23.03.0057 -
Current Opinion in Hematology Sep 2017Hemophilia is a debilitating disease, marked by frequent, painful bleeding events, joint deterioration and early death. All current treatments consist of i.v. infusions... (Review)
Review
PURPOSE OF REVIEW
Hemophilia is a debilitating disease, marked by frequent, painful bleeding events, joint deterioration and early death. All current treatments consist of i.v. infusions of replacement factor or other procoagulant factors, and are incompletely effective, due in part to the short half-lives of the proteins. An alternative approach is to rebalance hemostasis by inhibiting natural anticoagulant mechanisms. In this article, we explain why activated protein C (APC) is an appropriate and safe target for the treatment of hemophilia.
RECENT FINDINGS
A serpin (serine protease inhibitor) was engineered to specifically inhibit APC and was found to rescue hemostasis in a hemophilia mouse model, even after a severe tail clip injury. However, APC is also anti-inflammatory and has cytoprotective activities, raising safety concerns over the use of an APC inhibitor to treat hemophilia. We summarize the molecular basis of the anticoagulant and signaling activities of APC to assess the potential impact of targeting APC.
SUMMARY
We conclude that the signaling and anticoagulant functions of APC are in spatially and kinetically distinct compartments, and that it is possible to specifically inhibit the anticoagulant activity of APC. Targeting APC with a serpin is remarkably effective and may be safe for long-term prophylactic use in the treatment of hemophilia.
Topics: Animals; Disease Models, Animal; Drug Delivery Systems; Hemophilia A; Humans; Mice; Protein C; Serpins
PubMed: 28632502
DOI: 10.1097/MOH.0000000000000364 -
Scientific Reports Apr 2022Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective activities which make it an attractive target for diagnostic and therapeutic...
Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective activities which make it an attractive target for diagnostic and therapeutic applications. In this work, we present one-step activation of APC from a commercial source of protein C (PC, Ceprotin) followed by rapid and efficient purification using an APC-specific aptamer, HS02-52G, loaded on MyOne superparamagnetic beads. Due to the Ca-dependent binding of APC to HS02-52G, an efficient capturing of APC was applied in the presence of Ca ions, while a gentle release of captured APC was achieved in the elution buffer containing low EDTA concentration (5 mM). The captured and eluted APC showed more than 95% purity according to SDS-PAGE gel analysis and an enzyme-linked fluorescent assay (VIDAS Protein C). The purification yield of 45% was calculated when 4.2 µg APC was used, however this yield reduced to 21% if the starting amount of APC increased to 28.5 µg. Altogether, this method is recommended for rapid and efficient PC activation and APC purification. The purified APC can be used directly for downstream processes where high concentration of pure and active APC is needed.
Topics: Anticoagulants; Blood Coagulation Tests; Magnetic Iron Oxide Nanoparticles; Oligonucleotides; Protein C
PubMed: 35490167
DOI: 10.1038/s41598-022-11198-5 -
Chinese Journal of Traumatology =... 2015Acute coagulopathy of trauma-shock (ACoTS) occurs in 25% of patients with severe trauma in the early phase, and the mortality of those patients is four-fold higher than... (Review)
Review
Acute coagulopathy of trauma-shock (ACoTS) occurs in 25% of patients with severe trauma in the early phase, and the mortality of those patients is four-fold higher than patients without coagulopathy. The pathophysiology of this complicated phenomenon has been focused on in recent years. Tissue injury and hypoperfusion, activated protein C and Complements play important roles in the early phase after trauma. While the use of blood products, hypothermia, acidosis and inflammation are the main mechanism in late phase. Supplementing coagulation factors and platelets to improve ACoTS are inefficient. Only positive resuscitation from shock and improving tissue hypoperfusion have expected benefits.
Topics: Blood Coagulation Disorders; Complement System Proteins; Disseminated Intravascular Coagulation; Humans; Hypothermia; Inflammation; Protein C; Shock, Traumatic
PubMed: 26511301
DOI: 10.1016/j.cjtee.2015.01.003 -
Chinese Journal of Traumatology =... Dec 2018Trauma-induced coagulopathy is classified into primary and secondary coagulopathy, with the former elicited by trauma and traumatic shock itself and the latter being... (Review)
Review
Trauma-induced coagulopathy is classified into primary and secondary coagulopathy, with the former elicited by trauma and traumatic shock itself and the latter being acquired coagulopathy induced by anemia, hypothermia, acidosis, and dilution. Primary coagulopathy consists of disseminated intravascular coagulation and acute coagulopathy of trauma shock (ACOTS). The pathophysiology of ACOTS is the suppression of thrombin generation and neutralization of plasminogen activator inhibitor-1 mediated by activated protein C that leads to hypocoagulation and hyperfibrinolysis in the circulation. This review tried to clarify the validity of activated protein C hypothesis that constitutes the main pathophysiology of the ACOTS in experimental trauma models.
Topics: Acute Disease; Animals; Blood Coagulation Disorders; Disease Models, Animal; Disseminated Intravascular Coagulation; Humans; Mice; Plasminogen Activator Inhibitor 1; Protein C; Thrombin; Wounds and Injuries
PubMed: 30594428
DOI: 10.1016/j.cjtee.2018.07.005 -
FEBS Letters Jun 2005The anticoagulant protein C system regulates the activity of coagulation factors VIIIa and Va, cofactors in the activation of factor X and prothrombin, respectively.... (Review)
Review
The anticoagulant protein C system regulates the activity of coagulation factors VIIIa and Va, cofactors in the activation of factor X and prothrombin, respectively. Protein C is activated on endothelium by the thrombin-thrombomodulin-EPCR (endothelial protein C receptor) complex. Activated protein C (APC)-mediated cleavages of factors VIIIa and Va occur on negatively charged phospholipid membranes and involve protein cofactors, protein S and factor V. APC also has anti-inflammatory and anti-apoptotic activities that involve binding of APC to EPCR and cleavage of PAR-1 (protease-activated receptor-1). Genetic defects affecting the protein C system are the most common risk factors of venous thrombosis. The protein C system contains multi-domain proteins, the molecular recognition of which will be reviewed.
Topics: Animals; Anticoagulants; Blood Coagulation; Endothelium; Humans; Protein C; Protein S; Vitamin K
PubMed: 15943976
DOI: 10.1016/j.febslet.2005.03.001 -
International Journal of Molecular... Feb 2019Independent of its well-known anticoagulation effects, activated protein C (APC) exhibits pleiotropic cytoprotective properties. These include anti-inflammatory actions,... (Review)
Review
Independent of its well-known anticoagulation effects, activated protein C (APC) exhibits pleiotropic cytoprotective properties. These include anti-inflammatory actions, anti-apoptosis, and endothelial and epithelial barrier stabilisation. Such beneficial effects have made APC an attractive target of research in a plethora of physiological and pathophysiological processes. Of note, the past decade or so has seen the emergence of its roles in cutaneous wound healing-a complex process involving inflammation, proliferation and remodelling. This review will highlight APC's functions and mechanisms, and detail its pre-clinical and clinical studies on cutaneous wound healing.
Topics: Animals; Biomarkers; Clinical Trials as Topic; Disease Models, Animal; Genetic Engineering; Humans; Protein C; Recombinant Proteins; Signal Transduction; Skin; Skin Ulcer; Translational Research, Biomedical; Wound Healing
PubMed: 30791425
DOI: 10.3390/ijms20040903 -
Journal of Thrombosis and Haemostasis :... Apr 2023The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of... (Review)
Review
The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of the natural anticoagulants has greatly increased and we have also learned about antiinflammatory and cytoprotective activities expressed by antithrombin and activated protein C (APC). Some coagulation proteins have also been found to function as anticoagulants; e.g., thrombin when bound to thrombomodulin activates protein C. Another example is factor V (FV), which in addition to being a procofactor to FVa has emerged as an anticoagulant. The discovery of APC resistance, caused by FVLeiden, as a thrombosis risk factor resulted in the identification of FV as an APC cofactor working in synergy with protein S in the regulation of FVIIIa in the Xase complex. More recently, a natural anticoagulant FV splice isoform (FV-Short) was discovered when investigating the East Texas bleeding disorder. In FV-Short, the truncated B domain exposes a high-affinity binding site for tissue factor pathway inhibitor alpha (TFPIα), and together with protein S a high-affinity trimolecular complex is generated. The FXa-inhibitory activity of TFPIα is synergistically stimulated by FV-Short and protein S. The circulating FV-Short/protein S/TFPIα complex concentration is normally low (≈0.2 nM) but provides an anticoagulant threshold. In the East Texas bleeding, the concentration of the complex, and thus the threshold, is increased 10-fold, which results in bleeding manifestations. The anticoagulant properties of FV were discovered during investigations of individual patients and follow the great tradition of bed-to-bench and bench-to-bed research in the coagulation field.
Topics: Humans; Anticoagulants; Protein C; Factor V; Protein S; Blood Coagulation
PubMed: 36746318
DOI: 10.1016/j.jtha.2023.01.033 -
American Journal of Hematology Jun 2010Hereditary protein C deficiency is a hypercoagulable state associated with an increased risk for venous thrombosis. The recommended initial test for protein C is an... (Review)
Review
Hereditary protein C deficiency is a hypercoagulable state associated with an increased risk for venous thrombosis. The recommended initial test for protein C is an activity (functional) assay, which may be clotting time based or chromogenic. The advantages and disadvantages of the various testing options are presented. The causes of acquired protein C deficiency are much more common than hereditary deficiency. Therefore, this article describes the appropriate steps to take when protein C activity is low, to confirm or exclude a hereditary deficiency. The causes of falsely normal results are also described, including lupus anticoagulants and direct thrombin inhibitors.
Topics: Algorithms; Artifacts; Blood Coagulation Tests; Blood Proteins; Chromogenic Compounds; False Negative Reactions; False Positive Reactions; Humans; Immunoassay; Partial Thromboplastin Time; Protein C; Protein C Deficiency; Prothrombin Time; Reagent Kits, Diagnostic; Sensitivity and Specificity; Thrombophilia
PubMed: 20309856
DOI: 10.1002/ajh.21679 -
Blood Jul 2012Protein C is activated by thrombin with a value of k(cat)/K(m) = 0.11mM(-1)s(-1) that increases 1700-fold in the presence of the cofactor thrombomodulin. The molecular...
Protein C is activated by thrombin with a value of k(cat)/K(m) = 0.11mM(-1)s(-1) that increases 1700-fold in the presence of the cofactor thrombomodulin. The molecular origin of this effect triggering an important feedback loop in the coagulation cascade remains elusive. Acidic residues in the activation domain of protein C are thought to electrostatically clash with the active site of thrombin. However, functional and structural data reported here support an alternative scenario. The thrombin precursor prethrombin-2 has R15 at the site of activation in ionic interaction with E14e, D14l, and E18, instead of being exposed to solvent for proteolytic attack. Residues E160, D167, and D172 around the site of activation at R169 of protein C occupy the same positions as E14e, D14l, and E18 in prethrombin-2. Caging of R169 by E160, D167, and D172 is responsible for much of the poor activity of thrombin toward protein C. The E160A/D167A/D172A mutant is activated by thrombin 63-fold faster than wild-type in the absence of thrombomodulin and, over a slower time scale, spontaneously converts to activated protein C. These findings establish a new paradigm for cofactor-assisted reactions in the coagulation cascade.
Topics: Blood Coagulation; Catalytic Domain; Crystallography, X-Ray; Feedback, Physiological; Humans; Point Mutation; Protein C; Protein Interaction Domains and Motifs; Protein Structure, Tertiary; Prothrombin; Thrombin; Thrombomodulin
PubMed: 22535660
DOI: 10.1182/blood-2012-03-415323