Discovery of potential pharmacodynamic ingredients of Dang-Gui-Si-Ni decoction based on absorbed ingredients and molecular docking.

ETHNOPHARMACOLOGICAL RELEVANCE: The Dang-Gui-Si-Ni (DGSN) decoction as a classic prescription has been widely used for thousands of years in the clinical practice of traditional Chinese medicine (TCM). Especially in recent years, the potential efficacy of TCM for the treatment of Raynaud's syndrome has attracted great attention as there are still no specific remedies for this disease. However, the active constituents and underlying mechanisms responsible for the therapeutic benefits are not well understood, which makes it difficult to ensure quality control or to design research and drug development strategies. To identify the potential pharmacodynamic ingredients (PPIs) of TCM will help to achieve suitable process control procedures for industrial production and large-scale manufacturing. AIM OF THE STUDY: In the present study, we propose a multi-dimensional qualitative analysis method combining water-decoction spectra, in-vitro intestinal absorption spectra, in-vivo plasma spectra, and molecular docking of components to quickly identify the PPIs for the DGSN decoction of TCM. MATERIALS AND METHODS: Water-based decoctions of DGSN were prepared in accordance with the clinical use registered in ancient books. Ultra-high-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q/TOF-MS) coupled with computerized modelling activity screening was used to quickly identify the PPIs of the DGSN decoction. Bioactive compounds absorbed in vitro were identified using the everted intestinal sac model from rats and compounds absorbed in vivo were confirmed in portal vein blood samples obtained following oral administration in rats. Molecular docking validation experiments were adopted to predict the binding activity to coagulation factors I, II, VII, X, and IX. The active components were further confirmed by pharmacodynamics analysis. The anticoagulant activity of the DGSN decoction was verified using rat models. RESULTS: Thirty-one compounds were identified in the DGSN decoction. According to the in vivo experiments, 22 compounds that could be absorbed in vivo were detected by the everted intestinal sac model in rats. This model greatly reduces the scope of PPIs and is easy to perform. Ten compounds were detected in the portal vein blood in rats. The compounds detected in plasma provide stronger evidence supporting the PPIs. Molecular docking in vitro experiments indicated that 7 compounds exhibited better binding activity with coagulation factors I, II, VII, X, and IX. The animal experiments confirmed that the DGSN decoction could improve the microcirculation, providing indirect proof of anticoagulant activity suggested by the molecular docking studies. Finally, based on the multi-dimensional methods, 9 potential compounds present in the DGSN decoction were identified as PPIs (i.e., ferulic acid, paeoniflorin, albiflorin, chlorogenic acid, cryptochlorogenic acid, liquiritin, liquiritin apioside, cinnamaldehyde and glycyrrhizic acid). CONCLUSION: Overall, this study combined the water-decoction spectra, intestinal absorption spectra in vitro, plasma spectra in vivo, and molecular docking studies to establish a multi-dimensional qualitative analysis method of the DGSN decoction. Meanwhile, 9 compounds in DGSN decoction were identified as PPIs using this method, and are proposed for application as quality standards for complex TCM prescriptions.

Analysis of protein missense alterations by combining sequence- and structure-based methods.

BACKGROUND: Different types of in silico approaches can be used to predict the phenotypic consequence of missense variants. Such algorithms are often categorized as sequence based or structure based, when they necessitate 3D structural information. In addition, many other in silico tools, not dedicated to the analysis of variants, can be used to gain additional insights about the possible mechanisms at play. METHODS: Here we applied different computational approaches to a set of 20 known missense variants present on different proteins (CYP, complement factor B, antithrombin and blood coagulation factor VIII). The tools that were used include fast computational approaches and web servers such as PolyPhen-2, PopMusic, DUET, MaestroWeb, SAAFEC, Missense3D, VarSite, FlexPred, PredyFlexy, Clustal Omega, meta-PPISP, FTMap, ClusPro, pyDock, PPM, RING, Cytoscape, and ChannelsDB. RESULTS: We observe some conflicting results among the methods but, most of the time, the combination of several engines helped to clarify the potential impacts of the amino acid substitutions. CONCLUSION: Combining different computational approaches including some that were not developed to investigate missense variants help to predict the possible impact of the amino acid substitutions. Yet, when the modified residues are involved in a salt-bridge, the tools tend to fail, even when the analysis is performed in 3D. Thus, interactive structural analysis with molecular graphics packages such as Chimera or PyMol or others are still needed to clarify automatic prediction.

Clotting factors: Clinical biochemistry and their roles as plasma enzymes.

The purpose of this review is to describe structure and function of the multiple proteins of the coagulation system and their subcomponent domains. Coagulation is the process by which flowing liquid blood plasma is converted to a soft, viscous gel entrapping the cellular components of blood including red cells and platelets and thereby preventing extravasation of blood. This process is triggered by the minimal proteolysis of plasma fibrinogen. This transforms the latter to sticky fibrin monomers which polymerize into a network. The proteolysis of fibrinogen is a function of the trypsin-like enzyme termed thrombin. Thrombin in turn is activated by a cascade of trypsin-like enzymes that we term coagulation factors. In this review we examine the mechanics of the coagulation cascade with a view to the structure-function relationships of the proteins. We also note that two of the factors have no trypsin like protease domain but are essential cofactors or catalysts for the proteases. This review does not discuss the major role of platelets except to highlight their membrane function with respect to the factors. Coagulation testing is a major part of routine diagnostic clinical pathology. Testing is performed on specimens from individuals either with bleeding or with thrombotic disorders and those on anticoagulant medications. We examine the basic in-vitro laboratory coagulation tests and review the literature comparing the in vitro and in vivo processes. In vitro clinical testing typically utilizes plasma specimens and non-physiological or supraphysiological activators. Because the review focuses on coagulation factor structure, a brief overview of the evolutionary origins of the coagulation system is included.

Sensitivity and reproducibility improvements in a human plasma immunoassay with removal of clotting factors.

Interferences in human plasma immunoassay are severe challenge that affects the sensitivity and reproducibility of the assay. The clotting factor fibrinogen is a negatively charged protein and is one of the most common sources of interference in immunoassays, and its removal increases the sensitivity and reproducibility. Here, we present a highly sensitive and reproducible method for the detection of prostate specific antigen (PSA) in human plasma immunoassays. Protamine sulfate, a highly positively charged protein, was used to precipitate fibrinogen via ionic interaction to improve the sensitivity and reproducibility of human plasma immunoassay. In a sandwich ELISA for PSA using plasma and protamine-treated plasma samples, the limit of detection was improved from 413 pg/mL in plasma to 235 pg/mL in protamine-treated plasma samples, and the coefficient of variation known as a measure of reproducibility was significantly lowered by protamine treatment. The use of protamine sulfate in human plasma immunoassays for detection of PSA using quartz crystal microbalance (QCM) biosensors resulted in increased sensitivity and reproducibility by about 2-fold and 3-fold, respectively, relative to when not using protamine sulfate. Based on these results, protamine sulfate was the best choice to increase the sensitivity and reproducibility in immunoassays using plasma samples.

Maturation of coagulation factor IX during Xase formation as deduced using factor VIII-derived peptides.

Blood coagulation involves extrinsic and intrinsic pathways, which merge at the activation step of blood coagulation factor X to factor Xa. This step is catalysed by the extrinsic or intrinsic Xase, which consists of a complex of factor VIIa and its cofactor tissue factor or factor IXa (FIXa) and its cofactor coagulation factor VIIIa (FVIIIa). Upon complex formation with FVIIIa, FIXa is conformationally activated to the Xase complex. However, the mechanistic understanding of this molecular recognition is limited. Here, we examined FVIIIa-FIXa binding in the context of FIXa's activation status. Given the complexity and the labile nature of FVIIIa, we decided to employ two FVIII-derived peptides (558-loop, a2 peptide) to model the cofactor binding of FIX(a) using biosensor chip technology. These two FVIII peptides are known to mediate the key interactions between FVIIIa and FIXa. We found both of these cofactor mimetics as well as full-length FVIIIa bind more tightly to zymogenic FIX than to proteolytically activated FIXa. Consequently and surprisingly, we observed that the catalytically inactive FIX zymogen can outcompete the activated FIXa from the complex with FVIIIa, resulting in an inactive, zymogenic Xase complex. By contrast, the thrombophilic Padua mutant FIXa-R170 in complex with the protein-substrate analogue BPTI bound tighter to FVIIIa than to the zymogen form FIX-R170L, suggesting that the active Xase complex preferentially forms in the Padua variant. Together, these results provide a mechanistic basis for the thrombophilic nature of the FIX-R170L mutant and suggest the existence of a newly discovered safety measure within the coagulation cascade.

Three-factor prothrombin complex concentrates for refractory bleeding after cardiovascular surgery within an algorithmic approach to haemostasis.

BACKGROUND/OBJECTIVES: Prothrombin complex concentrates (PCC) are increasingly administered off-label in the United States to treat bleeding in cardiovascular surgical patients and carry the potential risk for acquired thromboembolic side-effects after surgery. Therefore, we hypothesized that the use of low-dose 3-factor (3F) PCC (20-30 IU/kg), as part of a transfusion algorithm, reduces bleeding without increasing postoperative thrombotic/thromboembolic complications. MATERIALS/METHODS: After IRB approval, we retrospectively analysed 114 consecutive, complex cardiovascular surgical patients (age > 18 years), between February 2014 and June 2015, that received low-dose 3F-PCC (Profilnine® ), of which seven patients met established exclusion criteria. PCC was dosed according to an institutional perioperative algorithm. Allogeneic transfusions were recorded before and after PCC administration (n = 107). The incidence of postoperative thromboembolic events was determined within 30 days of surgery, and Factor II levels were measured in a subset of patients (n = 20) as a quality control measure to avoid excessive PCC dosing. RESULTS: Total allogeneic blood product transfusion reached a mean of 12·4 ± 9·9 units before PCC and 5·0 ± 6·3 units after PCC administration (P < 0·001). The mean PCC dose was 15·8 ± 7·1 IU/kg. Four patients (3·8%) each experienced an ischaemic stroke on postoperative day 1, 2, 4 and 27. Seven patients (6·5%) had acquired venous thromboembolic disease within 10 days of surgery. Median factor II level after transfusion algorithm adherence and PCC administration was 87%. CONCLUSIONS: 3F-PCC use for refractory bleeding after cardiovascular surgery resulted in reduced transfusion of allogeneic blood and blood products. Adherence to this algorithmic approach was associated with an acceptable incidence of postoperative thrombotic/thromboembolic complications.

Gold nano-urchin integrated label-free amperometric aptasensing human blood clotting factor IX: A prognosticative approach for "Royal disease".

This article is clearly presenting the development of a biosensor for human factor IX (FIX) to diagnose the blood clotting deficiency, a so-called 'Royal disease' using an interdigitated electrode (IDE) with the zinc oxide surface modification. Gold nano-urchins (GNUs) with 60 nm in diameter was integrated into a streptavidin-biotinylated aptamer strategy to enhance the active surface area. Two different comparative studies have been done to validate the system to be practiced in the current work holds with a higher capability for the high-performance sense. Whereby, the presence and absence of GNUs in the aptasensing system for FIX interaction were investigated using the amperometric measurement, using a linear sweep voltage of 0-2 V at 0.01 V step voltage. The detection limit was 6 pM based on 3σ calculation when GNUs integrated aptamer assay was utilized for FIX detection, which shows 8 folds sensitivity enhancement comparing the condition in the absence of GNU and 50 folds higher than sensitive radio-isotope and surface plasmon resonance assays. Albeit, the surface and molecular characterizations were well demonstrated by scanning electron microscopy, atomic force microscopy, 3D nano-profilometry and further supports were rendered by UV-Vis spectroscopy and Enzyme-linked apta-sorbent assay (ELASA). Furthermore, the spiking experiment was done by FIX-spikes in human blood serum in order to demonstrate the stability with a higher non-fouling.

Stability of plasma proteins and factors in Chinese universal pooled plasma.

OBJECTIVE: This study aimed to determine the precision dose of Chinese universal pooled plasma (CUPP) developed by our laboratory, and the stability of plasma proteins and factors. METHODS: A total of 100 single fresh-frozen plasma (FFP) units were selected to test plasma proteins, including total protein, albumin, fibrinogen, factor V, factor VIII, antithrombin-III, and protein C. Different pooling protocols with 20, 40, 60, 80, and 100 units were used to optimize the number of pooled units. The pooled plasma was then used to further evaluate the optimal storage conditions and duration at 22°C, 4°C, and -20°C. RESULTS: There were considerable differences in plasma protein levels among single units of FFP. After different pooling protocols, the mean value of plasma proteins did not significantly change. However, with a larger number of pooled samples, plasma proteins were more stable with a smaller standard deviation. Acceptable storage for CUPP was achieved with storage for 1 day at 22°C, 4 days at 4°C, and 3 months at -20°C. CONCLUSION: A uniform level of plasma proteins and factors in CUPP appears to support establishment of a precise dose of plasma.

Phosphatidylcholine in the groove of endothelial cell protein C receptor (EPCR) regulates EPCR conformation and protein C recognition.

Endothelial cell protein C receptor (EPCR), the cellular receptor for protein C (PC), facilitates PC activation through the thrombin/thrombomodulin complex and regulates thrombin generation. Under pathophysiological conditions like sepsis, the interactions between EPCR and PC become impaired. Previous studies have demonstrated that the EPCR contains a phospholipid in the antigen-binding groove that is responsible for the structural stability of the EPCR and for PC recognition. However, an understanding at the atomic level during ligand recognition is not fully developed. Molecular dynamics simulations along with potential of mean force (PMF) calculations were carried out in order to provide molecular insight into the dynamics and free energies of EPCR-PC in the absence/presence of phospholipid, namely lysophosphatidylcholine (lysoPCh) and phosphatidylcholine (PCh) in the antigen-binding groove of the EPCR. Our data reveal that the presence of lipid maintains the optimal conformation of the EPCR for PC binding. PMF data further suggest that the PCh system is the most stable in comparison with the other systems (lysoPCh and no lipid). With regards to the two hydrophobic tails of PCh, one lipid tail regulates EPCR conformation while the other promotes ligand recognition by interacting with the keel residue (Phe-4) of PC. Due to the lack of one hydrophobic tail for the lysoPCh system, the EPCR conformation is retained but the affinity of the EPCR towards the ligand (PC) is reduced. Our studies for the first time explore the possible mode of ligand recognition by the EPCR via the involvement of phosphatidylcholine within its hydrophobic groove. The present work provides insight into PCh-dependent ligand recognition and hence regulation of the protein C/EPCR complex formation.

Anticoagulant mechanism, pharmacological activity, and assessment of preclinical safety of a novel fibrin(ogen)olytic serine protease from leaves of Leucas indica.

The harnessing of medicinal plants containing a plethora of bioactive molecules may lead to the discovery of novel, potent and safe therapeutic agents to treat thrombosis-associated cardiovascular diseases. A 35 kDa (m/z 34747.5230) serine protease (lunathrombase) showing fibrin(ogen)olytic activity and devoid of N- and O- linked oligosaccharides was purified from an extract of aqueous leaves from L. indica. The LC-MS/MS analysis, de novo sequencing, secondary structure, and amino acid composition determination suggested the enzyme's novel characteristic. Lunathrombase is an αß-fibrinogenase, demonstrating anticoagulant activity with its dual inhibition of thrombin and FXa by a non-enzymatic mechanism. Spectrofluorometric and isothermal calorimetric analyses revealed the binding of lunathrombase to fibrinogen, thrombin, and/or FXa with the generation of endothermic heat. It inhibited collagen/ADP/arachidonic acid-induced mammalian platelet aggregation, and demonstrated antiplatelet activity via COX-1 inhibition and the upregulation of the cAMP level. Lunathrombase showed in vitro thrombolytic activity and was not inhibited by endogenous protease inhibitors α2 macroglobulin and antiplasmin. Lunathrombase was non-cytotoxic to mammalian cells, non-hemolytic, and demonstrated dose-dependent (0.125-0.5 mg/kg) in vivo anticoagulant and plasma defibrinogenation activities in a rodent model. Lunathrombase (10 mg/kg) did not show toxicity or adverse pharmacological effects in treated animals.

Comparison of 3-Factor Versus 4-Factor Prothrombin Complex Concentrate With Regard to Warfarin Reversal, Blood Product Use, and Costs.

BACKGROUND: Prothrombin complex concentrates (PCCs) are drug products containing varying amounts of vitamin K-dependent coagulation factors II, VII, IX, and X. The evidence comparing 3-factor PCC (3-PCC) versus 4-factor PCC (4-PCC) for warfarin reversal is conflicting. It has been hypothesized that 3-PCC may be less effective than 4-PCC because of relatively lower factor VII content. STUDY QUESTION: The primary objective of this study was to compare international normalized ratio (INR) reversal between 3-PCC and 4-factor PCC (4-PCC) in warfarin-treated patients. The secondary objectives include comparing blood product use, total reversal costs, and cost-effectiveness between the groups. STUDY DESIGN: This was a retrospective cohort study conducted in 2 affiliated, academic institutions in the United States. Consecutive adult patients who received 3-PCC or 4-PCC for warfarin reversal were included. MEASURES AND OUTCOMES: The primary outcome was adequate INR reversal defined as a final INR ≤1.5. Secondary outcomes were the utilization of plasma, red blood cells and platelets, reversal costs, and the cost-effectiveness ratio. RESULTS: There were 89 patients who were included in the overall cohort (3-PCC = 57, 4-PCC = 32). Adequate INR reversal occurred less commonly with 3-PCC (45.6%) compared with 4-PCC (87.5%) (P < 0.001). There was no significant difference in the proportion of patients who received plasma (32% vs. 28%, P = 0.813), red blood cells (37% vs. 47%, P = 0.377), or platelets (16% vs. 28%, P = 0.180) between the 3-PCC and 4-PCC groups, respectively. The median reversal cost of 3-PCC ($3663) was lower than 4-PCC ($5105) (P = 0.001). The cost-effective ratio favored 4-PCC ($5105/87.5% = $5834) compared with 3-PCC ($3663/45.6% = $8033). CONCLUSIONS: Four-PCC was more effective than 3-PCC with regard to INR reversal in patients taking warfarin, but blood product use was similar. Although 4-PCC is associated with increased reversal costs, it may be cost-effective in terms of INR reversal.

Coagulation factor and protease pathways in thrombosis and cardiovascular disease.

The biochemical characterisation of the proteolytic pathways that constitute blood coagulation was one of the most relevant achievements in biomedical research during the second half of the 20th century. Understanding these pathways was of crucial importance for improving global health through application in haemostasis and thrombosis pathologies. Immediately after the cloning of the genes corresponding to these proteins, mutations were discovered in them that were associated with imbalances in haemostasis. Later, the importance of coagulation pathways in other pathological processes was demonstrated, such as in atherosclerosis and inflammation, both essential processes involved in vascular disease. In the present review we evaluate the concepts that have allowed us to reach the integrated vision on coagulation that we have today. The thrombo-inflammation model encompassing these aspects includes a pivotal role for the proteases of the coagulation pathway as well as the regulatory proteins thereof. These concepts illustrate the importance of the coagulation cascade in cardiovascular pathology, not only in thrombotic processes, but also in atherosclerotic processes and in the response to ischaemia-reperfusion injury, making it a central mechanism in cardiovascular disease.

Peptides derived from MARCKS block coagulation complex assembly on phosphatidylserine.

Blood coagulation involves activation of platelets and coagulation factors. At the interface of these two processes resides the lipid phosphatidylserine. Activated platelets expose phosphatidylserine on their outer membrane leaflet and activated clotting factors assemble into enzymatically active complexes on the exposed lipid, ultimately leading to the formation of fibrin. Here, we describe how small peptide and peptidomimetic probes derived from the lipid binding domain of the protein myristoylated alanine-rich C-kinase substrate (MARCKS) bind to phosphatidylserine exposed on activated platelets and thereby inhibit fibrin formation. The MARCKS peptides antagonize the binding of factor Xa to phosphatidylserine and inhibit the enzymatic activity of prothrombinase. In whole blood under flow, the MARCKS peptides colocalize with, and inhibit fibrin cross-linking, of adherent platelets. In vivo, we find that the MARCKS peptides circulate to remote injuries and bind to activated platelets in the inner core of developing thrombi.

Adaptive release of heparin from anticoagulant hydrogels triggered by different blood coagulation factors.

Feedback-controlled anticoagulant hydrogels were formed by crosslinking the anticoagulant heparin with star-shaped poly(ethylene glycol) using peptide linkers, which are selectively cleaved by different activated blood coagulation factors acting as proteolytic enzymes. Various cleavable peptide units, differing either in their thrombin turnover rates or in their responsiveness to factors activated earlier in the course of blood coagulation, were used for the formation of the biohybrid materials. Release triggered by the early coagulation factors Xa (FXa) or FXIIa/kallikrein was shown to enhance the efficiency of the released anticoagulant. Furthermore, FXa-cleavable gels enabled a faster release of heparin, which was attributed to the lower affinity of the factor for heparin. Combining early and fast responses, FXa-cleavable gels were shown to provide anticoagulant protection of biomaterial surfaces at low levels of released heparin in human whole-blood incubation experiments. The results demonstrate the potential for employing biomolecular circuits in the design of functional biomaterials to tailor the adaptive delivery of bioactive molecules.

Serum Amyloid P Component (SAP) Interactome in Human Plasma Containing Physiological Calcium Levels.

The pentraxin serum amyloid P component (SAP) is secreted by the liver and found in plasma at a concentration of approximately 30 mg/L. SAP is a 25 kDa homopentamer known to bind both protein and nonprotein ligands, all in a calcium-dependent manner. The function of SAP is unclear but likely involves the humoral innate immune system spanning the complement system, inflammation, and coagulation. Also, SAP is known to bind to the generic structure of amyloid deposits and possibly to protect them against proteolysis. In this study, we have characterized the SAP interactome in human plasma containing the physiological Ca2+ concentration using SAP affinity pull-down and co-immunoprecipitation experiments followed by mass spectrometry analyses. The analyses resulted in the identification of 33 proteins, of which 24 were direct or indirect interaction partners not previously reported. The SAP interactome can be divided into categories that include apolipoproteins, the complement system, coagulation, and proteolytic regulation.

A new manufacturing process to remove thrombogenic factors (II, VII, IX, X, and XI) from intravenous immunoglobulin gamma preparations.

Coagulation factors (II, VII, IX, X, and particularly XIa) remaining in high concentrations in intravenous immunoglobulin (IVIG) preparations can form thrombi, causing thromboembolic events, and in serious cases, result in death. Therefore, manufacturers of biological products must investigate the ability of their production processes to remove procoagulant activities. Previously, we were able to remove coagulation factors II, VII, IX, and X from our IVIG preparation through ethanol precipitation, but factor XIa, which plays an important role in thrombosis, remained in the intermediate products. Here, we used a chromatographic process using a new resin that binds with high capacity to IgG and removes procoagulant activities. The procoagulant activities were reduced to low levels as determined by the thrombin generation assay: <1.56 mIU/mL, chromogenic FXIa assay: <0.16 mIU/mL, non-activated partial thromboplastin time (NaPTT): >250 s, FXI/FXIa ELISA: <0.31 ng/mL. Even after spiking with FXIa at a concentration 32.5 times higher than the concentration in normal specimens, the procoagulant activities were below the detection limit (<0.31 ng/mL). These results demonstrate the ability of our manufacturing process to remove procoagulant activities to below the detection limit (except by NaPTT), suggesting a reduced risk of thromboembolic events that maybe potentially caused by our IVIG preparation.

3-Factor Versus 4-Factor Prothrombin Complex Concentrate for Warfarin Reversal in Severe Bleeding: A Multicenter, Retrospective, Propensity-Matched Pilot Study.

Current guidelines recommend 4-factor prothrombin complex concentrate (4PCC) for emergent reversal of bleeding secondary to warfarin. While current research has demonstrated superiority of 4PCC over plasma, direct comparisons with 3-factor PCC (3PCC) are lacking. The purpose of this study is to compare the efficacy and safety of 3PCC and 4PCC. We conducted a retrospective analysis of patients who received PCC at one of four medical centers. All patients in the 3PCC group were treated at one center that utilizes a fixed, weight-based dosing protocol. After evaluation of all patients meeting inclusion criteria, propensity-score matching was used to adjust for differences in treatment characteristics. There was no difference in the primary outcome of INR ≤ 1.4 between 3PCC and 4PCC in both the unmatched (85.7 vs. 90.6 %; p = 0.37) and matched (84.2 vs. 92.1 %; p = 0.48) analyses. There was a significant difference in goal INR achieved favoring 4PCC (56.3 vs 90.0 %; p < 0.02) when baseline INR > 4.0. A total of three thrombotic events were documented, all in the 4PCC group. We found no difference in the rate of INR reversal in those treated with 3PCC and 4PCC. However, those with a baseline INR > 4.0 may experience more successful INR reversal with 4PCC.

Different Heparin Contents in Prothrombin Complex Concentrates May Impair Blood Clotting in Outpatients With Ventricular Assist Devices Receiving Phenprocoumon.

OBJECTIVES: Prothrombin complex concentrates (PCCs) are used to rapidly reverse anticoagulation by oral vitamin K antagonists. They differ in the content of clotting factors, endogenous anticoagulants, and heparin. The authors hypothesized that PCCs' specific heparin content may compromise the hemostatic effect. DESIGN: Prospective ex-vivo investigation. SETTING: University hospital. PARTICIPANTS: Venous blood samples were obtained from 8 patients with implanted ventricular assist devices who also were receiving phenprocoumon. INTERVENTIONS: Four different 4-factor PCCs were added to patient blood to attain a calculated increase in prothrombin time by 20%, 40%, and 60% greater than baseline in paired experiments. MEASUREMENTS AND MAIN RESULTS: Clotting was measured using thromboelastometry and endogenous thrombin potential. Two heparin-containing PCCs prolonged the clotting times in a concentration-dependent manner compared with baseline (p<0.01) and compared with PCCs containing significantly less or no heparin (p<0.01). The PCCs containing low or no heparin enhanced the area under the curve of thrombin generation and peak thrombin several fold relative to the heparin-containing PCCs (p<0.01). One of the PCCs containing heparin even decreased peak thrombin generation by ~90% compared with baseline (p<0.01). PCC with low or no heparin shortened the lag phase (p<0.01), whereas 1 heparin containing PCC prolonged the lag phase by 66% (p<0.01). CONCLUSIONS: Physicians should be aware of the differences in heparin contents. Extrapolation of results from one agent to other PCC preparations may be difficult. Patients with an implanted left ventricular assist device and anticoagulated with vitamin-K antagonists could benefit from the use of PCC with low heparin content when surgery or bleeding requires emergency reversal. Further clinical studies are warranted.

Current structural biology of the heparin interactome.

Heparin is the best known therapeutically active carbohydrate. It can bind and regulate multiple functional proteins such as coagulation cofactors, chemokines, and growth factors. This versatility has led to the recently developed concept of the heparin interactome--a group of proteins that, as the name implies, interact with heparin. The heparin interactome is structurally and functionally diverse. Though natural ligands of this class of proteins may be any of the glycosaminoglycans however, their structural biology is generally studied using heparin as a model compound. NMR spectroscopy contributes significantly to structural investigations of the resultant complexes in solution. This review aims therefore at discussing the current status in structural biology of the molecular complexes formed between heparin and its protein partners through the current concept of the heparin interactome.

Biochemical characterization of prothrombin complex concentrates in China.

Despite increasing use of prothrombin complex concentrates (PCCs), there is little knowledge about the biochemical characterization of Chinese PCCs. Six Chinese PCCs were investigated and compared with PCCs (Octaplex®) from Europe. The levels of coagulation factors and inhibitors were detected. The presence of activated coagulation factors was assessed. Furthermore, their thrombin inhibitory capacities, specific activity and purity were assayed. All above parameters of biochemical properties were statistically analyzed. Chinese PCCs contained FⅡ, Ⅶ, Ⅸ and Ⅹ, protein C, S and Z, heparin and extremely low level antithrombin, as well as Octaplex®. The measured FⅨ activities were similar to those declared, however the measured potency of FⅡ, Ⅶ and Ⅹ greatly exceeded the labeled. Though all preparations were negative for activated coagulation factors in non-activated partial thromboplastin time test, the activated coagulation factor Ⅶ (FⅦa) remained in all PCCs and its content differed greatly. Overall, FⅦa content of Chinese PCCs was higher than that of Octaplex®. Further, Chinese PCCs were inferior to Octaplex® in the thrombin inhibitory capacities, specific activity and purity. In summary, compared with Octaplex®, Chinese PCCs' errors about the labeled activity of coagulation factors and probably high risks of thrombosis should be considered.