Natural Anticoagulant Proteins Research Articles

Protein S antibody as an adjunct therapy for hemophilia B

AbstractHemophilia B (HB) is caused by an inherited deficiency of plasma coagulation factor IX (FIX). Approximately 60% of pediatric patients with HB possess a severe form of FIX deficiency (<1% FIX activity). Treatment typically requires replacement therapy through the administration of FIX. However, exogenous FIX has a limited functional half-life, and the natural anticoagulant protein S (PS) inhibits activated FIX (FIXa). PS ultimately limits thrombin formation, which limits plasma coagulation. This regulation of FIXa activity by PS led us to test whether inhibiting PS would extend the functional half-life of FIX and thereby prolong FIX-based HB therapy. We assayed clotting times and thrombin generation to measure the efficacy of a PS antibody for increasing FIX activity in commercially obtained plasma and plasma from pediatric patients with HB. We included 11 pediatric patients who lacked additional comorbidities and coagulopathies. In vivo, we assessed thrombus formation in HB mice in the presence of the FIXa ± PS antibody. We found an accelerated rate of clotting in the presence of PS antibody. Similarly, the peak thrombin formed was significantly greater in the presence of the PS antibody, even in plasma from patients with severe HB. Furthermore, HB mice injected with PS antibody and FIX had a 4.5-fold higher accumulation of fibrin at the thrombus induction site compared with mice injected with FIX alone. Our findings imply that a PS antibody would be a valuable adjunct to increase the effectiveness of FIX replacement therapy in pediatric patients who have mild, moderate, and severe HB.

Antithrombin, Protein C, and Protein S: Genome and Transcriptome-Wide Association Studies Identify 7 Novel Loci Regulating Plasma Levels.

Antithrombin, PC (protein C), and PS (protein S) are circulating natural anticoagulant proteins that regulate hemostasis and of which partial deficiencies are causes of venous thromboembolism. Previous genetic association studies involving antithrombin, PC, and PS were limited by modest sample sizes or by being restricted to candidate genes. In the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium, we meta-analyzed across ancestries the results from 10 genome-wide association studies of plasma levels of antithrombin, PC, PS free, and PS total. Study participants were of European and African ancestries, and genotype data were imputed to TOPMed, a dense multiancestry reference panel. Each of the 10 studies conducted a genome-wide association studies for each phenotype and summary results were meta-analyzed, stratified by ancestry. Analysis of antithrombin included 25 243 European ancestry and 2688 African ancestry participants, PC analysis included 16 597 European ancestry and 2688 African ancestry participants, PSF and PST analysis included 4113 and 6409 European ancestry participants. We also conducted transcriptome-wide association analyses and multiphenotype analysis to discover additional associations. Novel genome-wide association studies and transcriptome-wide association analyses findings were validated by in vitro functional experiments. Mendelian randomization was performed to assess the causal relationship between these proteins and cardiovascular outcomes. Genome-wide association studies meta-analyses identified 4 newly associated loci: 3 with antithrombin levels (GCKR, BAZ1B, and HP-TXNL4B) and 1 with PS levels (ORM1-ORM2). transcriptome-wide association analyses identified 3 newly associated genes: 1 with antithrombin level (FCGRT), 1 with PC (GOLM2), and 1 with PS (MYL7). In addition, we replicated 7 independent loci reported in previous studies. Functional experiments provided evidence for the involvement of GCKR, SNX17, and HP genes in antithrombin regulation. The use of larger sample sizes, diverse populations, and a denser imputation reference panel allowed the detection of 7 novel genomic loci associated with plasma antithrombin, PC, and PS levels.

In vivo generation of thrombin in patients with liver disease without apparent evidence of activation of the intrinsic or extrinsic pathway of coagulation

BackgroundPatients with liver diseases are in a hypercoagulable state, as evidenced by enhanced in vitro thrombin generating capacity and elevated plasma levels of markers of in vivo thrombin generation. However, it is unknown by which mechanism in vivo activation of coagulation occurs. ObjectivesWe aimed to clarify the mechanisms underlying enhanced in vivo thrombin generation to provide a rationale for targeted anticoagulant therapy. Patients/MethodsOverall, 191 patients diagnosed with stable or acutely decompensated cirrhosis, acute liver failure or injury, acute-on-chronic liver failure, or sepsis without underlying chronic liver disease were recruited from King’s College Hospital, London, from 2017 to 2021 and compared with reference values of 41 healthy controls. We measured levels of markers of in vivo activation of coagulation and activation of the intrinsic and extrinsic pathways, their respective zymogens, and natural anticoagulants. ResultsThrombin-antithrombin complexes, prothrombin fragment 1+2 (F1+2), and D-dimer levels were increased in acute and chronic liver disease, proportional to disease severity. Plasma levels of free activated factor XII (FXIIa), C1-esterase-inhibitor (C1inh)-FXIIa, C1inh-factor XI, C1inh-plasma kallikrein, factor-VIIa-antithrombin-complexes, and activated FVII were reduced in acute and chronic liver disease, even after adjusting for zymogen levels, which were also substantially reduced. Natural anticoagulants antithrombin and protein C were profoundly reduced in liver patients. ConclusionsThis study provides evidence of enhanced thrombin generation in liver disease without detectable activation of the intrinsic or extrinsic pathway. We propose that defective anticoagulant mechanisms highly amplify the low-grade activation of coagulation by either pathway.

The Assessment of Anticoagulative System: Two Natural Anticoagulants Protein C and Antithrombin III

The Assessment of Anticoagulative System: Two Natural Anticoagulants Protein C and Antithrombin III

Maternal and Neonatal Hemostasis.

Hemostasis is a dynamic process that begins at early stages of fetal development. The hemostatic system comprises procoagulant, natural anticoagulant, and fibrinolytic proteins that interact with each other, as well as with the endothelial wall and blood cells in a complex, yet balanced manner, aiming to avoid either bleeding or thrombosis. Pregnancy is a unique physiological state in which natural biologic alterations predispose both mothers and their offspring to higher risk of hypercoagulability and bleeding. This special issue of Seminars in Thrombosis and Hemostasis is dedicated to maternal and neonatal hemostasis.

AN OVERVIEW ON HEREDITARY AND ACQUIRED HYPERCOAGULABILITY

A typical definition of hypercoagulability is the predisposition to develop venous thromboembolism due to an underlying hypercoagulable state caused by hereditary or acquired blood coagulation or fibrinolysis problems. Clinical signs of hypercoagulability can be fatal or extremely damaging. About 80% to 90% of patients can have hypercoagulability diseases accurately recognised. Determining the origin of hypercoagulability may influence the kind and length of treatment for the accompanying thrombosis. As a result, hypercoagulability is not a single, unified disease process but rather a collection of risk factors that may or may not lead to thrombosis, depending on the severity and number of risk variables as well as environmental exposures. The former includes prothrombotic polymorphisms in the genes encoding for factor V (i.e., factor V Leiden) and prothrombin, as well as shortages of natural anticoagulants such antithrombin, protein C, and protein S. It also includes elevated values of clotting factors (particularly factor VIII). The latter problems mostly include hyperhomocysteinemia, acquired elevations of coagulation factors or acquired reductions of natural inhibitors, malignancy, and antiphospholipid antibody syndrome.

A Mini-Review Towards the Assessment of two Natural Anticoagulants Protein C And Antithrombin III

A Mini-Review Towards the Assessment of two Natural Anticoagulants Protein C And Antithrombin III

Antithrombin-Specific RNA Aptamers As a Potential Therapy to Restore Hemostatic Balance in Hemophilia Patients

Hemophilia A and B are inherited blood bleeding disorders due to insufficient blood coagulation factors. Individuals with hemophilia A have a deficiency in factor VIII, while individuals with hemophilia B have a deficiency in factor IXa. Both of these factors are important in the intrinsic pathway of blood coagulation. In the absence of these factors, hemophilia patients are prone to bleeding. Thrombin, the primary factor in the blood coagulation pathway, promotes blood clotting and prevents bleeding. Hemophilia patients develop insufficient thrombin, resulting in an imbalance between the procoagulant and anticoagulant systems. Thus, generating more thrombin activity in these patients is an ideal therapeutic approach. We propose to increase thrombin's activity by inhibiting the primary inhibitor of thrombin and the natural anticoagulant protein, antithrombin (AT), using RNA molecules (aptamers) that bind to their target protein with high affinity and specificity. Several aptamers are evaluated in clinical trials as therapies for various blood diseases. We hypothesized that AT-specific aptamers could inhibit AT activity by preventing AT from forming a high molecular weight complex with thrombin, resulting in an overall increase in thrombin activity and restoring hemostatic equilibrium. The main goal is to design novel therapeutic molecules that promote thrombus formation in hemophilia patients. Using Systematic evolution of ligands by exponential enrichment (SELEX), we developed a library of RNA aptamers molecules that bind to AT with high to moderate affinity. We assessed the individual aptamers' ability to inhibit AT and increase thrombin activity using various in vitro methods. Three individual aptamers inhibited AT activity by preventing AT from forming a complex with thrombin in the presence and absence of heparin, resulting in a significant increase in thrombin activity. We also showed a decrease in thrombin generation using an ex vivo thrombin generation assay in the presence of aptamers. Our data illustrate that AT-specific RNA aptamers can inhibit AT activity and increase thrombin activity. Thus, these molecules could potentially be used to treat patients with both hemophilia A and B. Additional studies are being conducted to assess their ability to increase thrombin activity in a pre-clinical model.

Perioperative Coagulation Profile in Major Liver Resection for Cancer: A Prospective Observational Study

Hepatectomy-induced coagulation disturbances have been well studied over the past decade. Cumulative evidence supports the superiority of global coagulation analysis compared with conventional coagulation tests (i.e., prothrombin time or activated partial thromboplastin time) for clinical decision making. Cancer, however, represents an acquired prothrombotic state and liver resection for cancer deserves a more thorough investigation. This prospective observational study was conducted to assess the perioperative coagulation status of patients undergoing major hepatectomies for primary or metastatic hepatic malignancy. Patients were followed up to the 10th post-operative day by serial measurements of conventional coagulation tests, plasma levels of coagulation factors, and thrombin generation assay parameters. An abnormal coagulation profile was detected at presentation and included elevated FVIII levels, decreased levels of antithrombin, and lag time prolongation in thrombin generation. Serial hematological data demonstrated increased Von Willebrand factor, FVIII, D-dimer, fibrinogen and decreased levels of natural anticoagulant proteins in the early post-operative period predisposing to a hyper-coagulable state. The ratio of the anticoagulant protein C to the procoagulant FVIII was low at baseline and further declined post-operatively, indicating a prothrombotic state. Though no bleeding complications were reported, one patient experienced pulmonary embolism while under thromboprophylaxis. Overall, patients with hepatic carcinoma presenting for elective major hepatectomy may have baseline malignancy-associated coagulation disturbances, aggravating the hyper-coagulable state documented in the early post-operative period.

Global hemostatic profiling in patients with decompensated cirrhosis and bacterial infections

Background & AimsBacterial infections in cirrhosis are associated with increased bleeding risk. To assess the factors responsible for bleeding tendency in patients with bacterial infections, we conducted a prospective study comparing all 3 aspects of hemostasis (platelets, coagulation, and fibrinolysis) in hospitalized patients with decompensated cirrhosis with vs. without bacterial infections.MethodsPrimary hemostasis assessment included whole blood platelet aggregation and von Willebrand factor (VWF). Coagulation assessment included procoagulant factors (fibrinogen, factor II, V, VII, VIII, IX, X, XI, XII, XIII), natural anticoagulants (protein C, protein S, antithrombin) and thrombomodulin-modified thrombin generation test. Fibrinolysis assessment included fibrinolytic factors (plasminogen, t-PA, PAI-1, α2-AP, TAFIa/ai) and plasmin-antiplasmin complex (PAP).ResultsEighty patients with decompensated cirrhosis were included (40 with and 40 without bacterial infections). Severity of cirrhosis and platelet count were comparable between groups. At baseline, patients with cirrhosis and bacterial infections had significantly lower whole blood platelet aggregation, without significant differences in VWF. Regarding coagulation, bacterial infections were associated with reduced procoagulant factors VII and XII, and a significant reduction of all natural anticoagulants. However, thrombomodulin-modified thrombin generation was comparable between the study groups. Finally, although mixed potentially hypo-fibrinolytic (lower plasminogen) and hyper-fibrinolytic (higher t-PA) changes were present in bacterial infections, a comparable level of PAP was detected in both groups. Upon resolution of infection (n = 29/40), platelet aggregation further deteriorated whereas coagulation and fibrinolysis factors returned to levels observed in patients without bacterial infections.ConclusionIn hospitalized patients with decompensated cirrhosis, bacterial infections are associated with reduced whole blood platelet aggregation and a significant decrease of all natural anticoagulants, which may unbalance hemostasis and potentially increase the risk of both bleeding and thrombosis.Lay summaryBacterial infections are a common issue in hospitalized patients with decompensated cirrhosis (i.e. patients hospitalized due to severe complications of advanced chronic liver disease). Patients with decompensated cirrhosis who acquire infections may be at increased risk of bleeding complications following invasive procedures (that is a procedure in which the body is penetrated or entered, for instance by a needle or a tube). As bleeding complications in decompensated cirrhosis are associated with a high risk of further decompensation and death, there is an urgent need to understand the factors responsible for such increased bleeding tendency. Herein, we investigated the alterations of hemostasis (that is the physiological process responsible for clot formation and stability) in patients with decompensated cirrhosis and bacterial infections. We found that development of bacterial infections in these patients is associated with alterations of hemostasis (particularly of platelets and clotting cascade) that may increase the risk of both bleeding and thrombotic complications.

Inherited Thrombophilia in the Era of Direct Oral Anticoagulants.

Severe inherited thrombophilia includes rare deficiencies of natural anticoagulants (antithrombin and proteins C and S) and homozygous or combined factor V Leiden and FII G20210A variants. They are associated with a high thrombosis risk and can impact the duration of anticoagulation therapy for patients with a venous thromboembolism (VTE) event. Therefore, it is important to diagnose thrombophilia and to use adapted anticoagulant therapy. The widespread use of direct anticoagulants (DOACs) for VTE has raised new issues concerning inherited thrombophilia. Concerning inherited thrombophilia diagnosis, DOACs are directed toward either FIIa or FXa and can therefore interfere with coagulation assays. This paper reports DOAC interference in several thrombophilia tests, including the assessment of antithrombin, protein S, and protein C activities. Antithrombin activity and clot-based assays used for proteins C and S can be overestimated, with a risk of missing a deficiency. The use of a device to remove DOACs should be considered to minimize the risk of false-negative results. The place of DOACs in the treatment of VTE in thrombophilia patients is also discussed. Available data are encouraging, but given the variability in thrombosis risk within natural anticoagulant deficiencies, evidence in patients with well-characterized thrombophilia would be useful.

Reference interval of antithrombin, protein C, and protein S activities in healthy adults in Iran, the effect of age, sex, oral contraceptive intake, and menopause.

Antithrombin (AT), protein C (PC), and protein S (PS) are natural anticoagulant proteins that deficiency in each of them is associated with an increased risk of venous thromboembolism.The overlapping of plasma levels of AT, PC, and PS between healthy individuals and heterozygote carriers poses significant challenges in precise diagnosis. This study aimed to evaluate the effect of most influencing variables on plasma levels of these proteins and propose specific reference intervals to improve the interpretation of the laboratory results. This study was conducted on 1464 individuals who were referred to Massoud medical laboratory, Tehran, Iran, from 2019 to 2020. AT and PC were measured through chromogenic assay and PS plasma level with the clot-based assay. A multivariable linear regression model was performed to evaluate the effect of sex, age, oral contraceptive (OCP) intake, and menopause state. Normal deviate z value was used for different subgroups to justify the need for a separate reference interval. 1200 verified healthy individuals (434males and 766 females), aged between 18 and 69years were included in the study. The mean±SD age of the participants was 39.78±11.79years. The age-related effects for AT were found in men. In females, increasing age was associated with a rise in AT, PC, and PS plasma levels. No sex difference was found in AT plasma level. OCP-taking is associated with a decrease in AT and an increase in PC plasma levels. This is the largest study ever conducted on healthy individuals in the Iranian population, using specific reference interval results in accurate diagnosis of true AT, PC, and PS deficiency.

P-8 PRESERVATION OF THROMBIN GENERATION IN CIRRHOSIS DESPITE ABNORMAL RESULTS OF INTERNATIONAL NORMALIZED RATIO: IMPLICATIONS FOR INVASIVE PROCEDURES

Thrombin generation (TG) is normal or elevated in patients with cirrhosis when tested in the presence of thrombomodulin (TM), the activator of the main natural anticoagulant protein C. However, the relationship between TG with bleeding has been little explored in literature. To assess the relation among TG potential, measured without and in presence of TM, INR and the occurrence of bleeding after endoscopic band ligation of esophageal varices. 97 consecutive patients with cirrhosis were prospectively included (58 men; 54±10 years) and divided into two groups INR< 1.5 (n=72) or INR ≥1.5 (n=25). 46 healthy individuals were tested as controls. Endogenous thrombin potential (ETP) was measured without and with the addition of TM. ETP measured without TM was reduced in patients with cirrhosis when compared to controls, but no significant difference was found between the INR< 1.5 and INR ≥1.5 groups (1,250±315.7 versus 1,186±238 nmol/L x min; p= 0.3572). After addition of TM, both groups generated thrombin comparable to controls (INR ≥1.5: 965.9±232.3; INR<1.5: 893.0±368.6; controls: 915.0±458 nmol/L x min). 80% of patients had high ETP without/with TM ratio, indicating trend to hypercoagulability, which was more marked in the INR ≥1.5 group (0.81±0.1 versus 0.69±0.2; p=0.0042). Post-EVL bleeding occurred in 5.2% of the patients (INR<1.5, n=3; INR ≥1.5, n=2), all of them with ETP. without/with TM ratio ranging from 0.72 to 0.90 (controls 0.57±0.21). This study shows that TG in the presence of TM was normal in most patients with cirrhosis, including those with high INR value, but did not correlate with post-EVL bleeding. INR values and RETP values according to Child-Pugh class.

Dynamics of hemostasiological parameters in cows during pregnancy, after birth and in obstetric, gynecological and orthopedic pathology

It is established that the physiological course of the gestational process occurs with the intensification of coagulation processes in the hemostasis system with thrombophilia, which has a two–phase nature – from the first month of pregnancy to the seventh and in the period of 2–3 days to calving with a peak of hypercoagulation by 2–5 that day after birth. The activation of hemostasis components is correlated with a high level of natural anticoagulant protein C and increased fibrinolysis activity through tissue plasminogen activator, which is controlled by a high level of its type I inhibitor. The main hemostasiological criteria are the levels: in phase I – fibrinogen 4,9–6,1 g/l, soluble fibrin about 0,04 g/l, activated partial thromboplastin time 38,1–39,7 s, functionally inactive forms prothrombin 0,88 ± 0,2 mg/ml in the first month of pregnancy; in phase II – fibrinogen 5,1–7,0 g/l, soluble fibrin about 0,01 g/l, functionally inactive forms of prothrombin 0,17 ± 0,05 mg/ml and protein C 72,0 ± 1,4 % after childbirth. In obstetric and gynecological pathology, the hypercoagulable state is aggravated to consumption coagulopathy, which is reflected in high plasma levels of soluble fibrin – 0,064 ± 0,005 g/l, fibrin / fibrinogen cleavage products – 7,5 ± 0,4 μg/ml, functionally inactive forms of prothrombi. – 1,90 ± 0,34 mg/ml and inhibitor of tissue plasminogen activator type I – 45,8 ± 0,9 IU/ml at the lowest level of tissue plasminogen activator – 0,38 ± 0,08 IU/ml (according to the norms 1,1–1,3 IU/ml) and protein C deficiency – &lt;70%. Hypercoagulation in pregnant cows with purulent– necrotic lesions of the extremities is exacerbated by more pronounced hyperfibrinogenemia, an increase in its metabolites by 2,7 times (p&lt;0,05) and a decrease in the activity of F XIII by 1,3 times (p&lt;0,05) and the amount in the blood of proteinase inhibitor α2–M – 1,6 times (p&lt;0,05). At the same time, the hypercoagulation syndrome in cows with obstetric and gynecological pathology due to its comorbidity with orthopedic not only intensifies, which is expressed in an increase in the level of hyperfibrinogenemia by 1,2 times (p&lt;0,05), reduction of general coagulation tests by 1,3–2,1 times (p&lt;0,001) and a decrease in the activity of FXIII in 1,2–1,3 (p&lt;0,05), but is complicated by a decrease in the antiproteinase potential of the blood in 1,6–1,8 times. Key words: cows, pregnancy, obstetric, gynecological pathology, purulent-necrotic lesions in the area of fingers, hemostasiological indicators.

The Impact of Anticoagulant Activity of Tissue Factor Pathway Inhibitor Measured by a Novel Functional Assay for Predicting Deep Venous Thrombosis in Trauma Patients: A Prospective Nested Case-Control Study.

ObjectiveDeep venous thrombosis (DVT) is a common complication in patients with traumatic injury. Tissue factor pathway inhibitor (TFPI) is a natural anticoagulant protein in the extrinsic coagulation pathway. However, the relationship between DVT after trauma and the anticoagulant activity of TFPI remains unclear. In this prospective study, we investigated the role of TFPI in trauma patients with DVT to evaluate whether the anticoagulant activity of TFPI measured by a new functional assay can be used to help predict the risk of DVT. Patients and methods: This prospective nested case-control study enrolled trauma patients and healthy volunteers. Forty-eight trauma patients diagnosed with DVT and forty-eight matched trauma patients without DVT were included in the study. 120 healthy volunteers were also included as controls. Blood samples and case information were collected at admission. Patients accepted angiography before surgery to diagnose DVT. The parameters examined included TFPI anticoagulant activity, free-TFPI antigen, blood cell counts, and routine clinical coagulation tests. Results: For the parameters of TFPI anticoagulant activity, three were markedly increased in the DVT group compared to the non-DVT group (TFPI initial anticoagulant time ratio, P  =  .022; TFPI whole anticoagulant time ratio, P  =  .048; and TFPI anticoagulant rate, P  =  .034). The free-TFPI antigen concentration also showed a significant increasing trend in trauma patients with DVT compared with trauma patients without DVT (P  =  .035). Multivariate logistic regression analysis identified four independent factors for the development of DVT (TFPI initial anticoagulant time ratio, free-TFPI antigen, prothrombin time, and red blood cell count). We calculated the TFPI correlation coefficient and found that the area under the receiver operating characteristic curve was .821. Conclusions: A novel functional assay was developed to measure the anticoagulant activity of TFPI. The anticoagulant activity of TFPI can be used as a potential biomarker for diagnosing DVT in trauma patients.

Preservation of thrombin generation in cirrhosis despite abnormal results of international normalized ratio: implications for invasive procedures.

Thrombin generation is normal or elevated in patients with cirrhosis when tested in the presence of thrombomodulin, the activator of the main natural anticoagulant protein C. However, the relationship between thrombin generation with bleeding has been little explored in literature. 97 Consecutive patients with cirrhosis were prospectively included (58 men; 54 ± 10 years) and divided into two groups international normalized ratio (INR) less than 1.5 (n = 72) or INR at least 1.5 (n = 25). 46 Healthy individuals were tested as controls. Endogenous thrombin potential (ETP) was measured without and with the addition of thrombomodulin. ETP measured without thrombomodulin was reduced in patients with cirrhosis when compared with controls, but no significant difference was found between the INR less than 1.5 and INR at least 1.5 groups (1250 ± 315.7 versus 1186 ± 238 nmol/l × min; P = 0.3572). After the addition of thrombomodulin, both groups generated thrombin comparable with controls (INR ≥ 1.5: 965.9 ± 232.3; INR < 1.5: 893.0 ± 368.6; controls: 915.0 ± 458 nmol/l × min). 80% of patients had high ETP without/with thrombomodulin ratio, demonstrating the resistance to the anticoagulant action of thrombomodulin for both groups. This was more marked in the INR at least 1.5 group (0.81 ± 0.1 versus 0.69 ± 0.2; P = 0.0042). Postligation of esophageal varices bleeding occurred in 5.2% of patients (INR < 1.5, n = 3; INR ≥ 1.5, n = 2), all of them with ETP without/with thrombomodulin ratio ranging from 0.72 to 0.90 (controls 0.57 ± 0.21). This study confirms that thrombin generation in the presence of thrombomodulin was normal in most patients with cirrhosis, including those with high INR value, but did not correlate with postligation of esophageal varices bleeding.

Diet-Dependent and Diet-Independent Hemorheological Alterations in Celiac Disease: A Case-Control Study.

INTRODUCTION:Hemorheology is the study of the flow properties of the blood and its elements, which, together with natural anticoagulants, are important determinants of cardiovascular events. This study aimed to assess hemorheological and natural anticoagulant profiles of patients with celiac disease (CeD) comprehensively.METHODS:Our study is a case-control study (registered under ISRCTN49677481) comparing patients with CeD with age- and sex-matched control subjects (1:1). We measured erythrocyte deformability (ED) at high (3–30 Pa) and low shears (0.3–3 Pa), erythrocyte aggregation, whole blood viscosity, plasma viscosity, and natural anticoagulants (protein C, protein S, and antithrombin activity). Adherence to gluten-free diet was estimated through dietary interview and urine gluten immunogenic peptide (urine GIP) detection.RESULTS:After matching, we analyzed the data of 100 study participants. ED at high shears was impaired in CeD (P < 0.05 for all shears, confirmed by random forest analysis) independently of findings on CeD-specific serological assessment and urine GIP detection but slightly dependently on dietary adherence (P = 0.025 for 30 Pa shear). ED at low shears seemed to be impaired only in urine GIP+ CeD patients (P < 0.05 for all comparisons with urine GIP− CeD patients and control subjects). All parameters describing erythrocyte aggregation and whole blood viscosity were shifted toward a prothrombotic direction in patients with CeD with poor dietary adherence compared with those with good dietary adherence. Plasma viscosity and activity of natural anticoagulants did not differ across groups.DISCUSSION:We observed diet-dependent and diet-independent prothrombotic hemorheological alterations in CeD, which can contribute to the elevated cardiovascular risk. The untoward metabolic changes during gluten-free diet, which can further aggravate hemorheological status, may indicate the implementation of prevention strategies.

POSTPARTUM CEREBRAL VENOUS THROMBOSIS ASSOCIATED WITH PROTEIN S DEFICIENCY: A CASE REPORT

There is a decline in the levels of protein S during pregnancy due to an increase in its binding protein. Thus, protein S deficiency increases the risk of thrombosis and may lead to poor pregnancy outcomes. In the setting of a hypercoagulable state during pregnancy, it is difficult to interpret protein S levels when measured with other tests of thrombophilia in pregnancy. The rate of developing thrombotic events is higher in those pregnant females with a deficiency of any natural anticoagulant like protein S. We report the case of a recently delivered female with multiple intracranial hemorrhages and cerebral venous thrombosis associated with protein S deficiency. This case highlights the need to extensively identify all risk factors of thrombosis in newly delivered females for the early and effective management of postpartum thrombosis.

Plasma Protein Signatures of a Murine Venous Thrombosis Model and Slc44a2 Knockout Mice Using Quantitative-Targeted Proteomics.

The plasma compartment of the blood holds important information on the risk to develop cardiovascular diseases such as venous thrombosis (VT). Mass spectrometry-based targeted proteomics with internal standards quantifies proteins in multiplex allowing generation of signatures associated with a disease or a condition. Here, to demonstrate the method, we investigate the plasma protein signatures in mice following the onset of VT, which was induced by RNA interference targeting the natural anticoagulants antithrombin and protein C. We then study mice lacking Slc44a2, which was recently characterized as a VT-susceptibility gene in human genome-wide association studies. We use a recently developed panel of 375 multiplexed mouse protein assays measured by mass spectrometry. A strong plasma protein siganture was observed when VT was induced. Discriminators included acute phase response proteins, and proteins related to erythrocyte function. In mice lacking Slc44a2, protein signature was primarily overruled by the difference between sexes and not by the absent gene. Upon separate analyses for males and females, we were able to establish a signature for Slc44a2 deficiency, in which glycosylation-dependent cell adhesion molecule-1 and thrombospondin-1 were shared by both sexes. The minimal impact of Slc44a2 deficiency on the measured plasma proteins suggests that the main effect of Slc44a2 on VT does not lay ultimately in the plasma compartment. This suggests further investigation into the role of this VT-susceptibility gene should perhaps also question the possible involvement in cellular mechanisms.

Clinical Features of Visual Disturbances in Leiden Thrombophilia

The hereditary thrombophilias is a well-recognized important risk factor for a systemic and local thromboembolic events development. The case of Leiden thrombophilia family inheritance concomitant by the visual disturbances development are shown in this аrticle. Most commonly in hereditary thrombophilias, venous thrombembolias occur, arterial occlusions which have been reported in the recent literature only as individual clinical cases occur more rarely. In the European population hereditary thrombophilias are associated with a prothrombotic mutation in the coagulation factor V gene (Leiden factor) in a greater degree; herewith the risk of thrombotic complications is increasing significantly in homozygous polymorphism forms. Presence of combined mutations in several clotting factors also leads to risk of thrombembolias increase. Consequence of the Leiden mutation is a V activator resistance to the resolving action of the activated protein C which is a natural endogenous anticoagulant protein. Resistance development leads to a deceleration of V factor inactivation and to increasing of the thrombin amount. In the work presented here, development of the consistent bilateral occlusion of the central retinal artery (CRA) in a middle-aged patient with a heterozygous form of Leiden thrombophilia is the subject of interest. Along with the hereditary hemostatic system abnormality, the patient also had cardiovascular risk factors (hypertensive disease, atherosclerosis) which had a potentiating effect on the occlusion development. Taking into account the autosomal dominant nature of the Leiden mutation inheritance, the patient’s only daughter was examined; brief episodes of amaurosis fugax against the background of headaches similar to migraine were detected due to ophthalmological abnormalities. For verification of the Leiden thrombophilia diagnosis, both patients underwent molecular genetic diagnostics. Currently there are no large prospective studies showing the optimal and economically viable approach for identification of thrombophilia genetic polymorphisms in patients with retinal vascular occlusions in daily clinical experience. Possible additional risk factors for thrombembolias development, prevention services for manifest and recurrent vascular occlusions in patients with hereditary blood coagulation system abnormalities and their relatives are discussed in this article.