Mutations in antithrombin (SERPINC1) lead to the hereditary antithrombin deficiency. Conventional therapies for hereditary antithrombin deficiency are prophylactic or on-demand oral anticoagulants, which have poor compliance and side effects. This study explored the therapeutic efficacy of adeno-associated virus serotype 8 (AAV8)-mediated human SERPINC1 gene (AAV8-hSERPINC1) in AT (antithrombin)-deficiency mice. AAV8-hSERPINC1 carrying luciferase was injected into AT+/- mice via tail vein injection at low, medium, and high doses. The biodistribution and expression of the carrier were visualized by in vivo bioimaging technology. Plasma AT levels were serially monitored by ELISA, and an inferior vena cava model was established to evaluate thrombotic propensity. Safety was evaluated by monitoring hepatic, renal, and cardiac function parameters and employing flow cytometry. A dose-dependent increase in AT expression was observed in AT+/- mice after AAV8-hSERPINC1 injection. Compared with the untreated mice, medium-dose treatment restored plasma AT activity and antigen in AT+/- mice to normal levels by week 8, with maintenance within the normal reference range for 40 weeks. In the venous thrombosis model, the rate of thrombosis in mice treated with medium-dose AAV8-hSERPINC1, rivaroxaban, low-molecular-weight-heparin, and wild-type mice were 60%, 60%, 70% and 60%, respectively. After AAV injection, transient elevations in hepatic transaminases and cytokines were observed in mice during a short-term period. Our study demonstrates that AAV8-hSERPINC1 gene delivery resulted in durable AT expression, sustained blood hypercoagulation state correction, thereby rescuing thrombophilia in AT-deficient male mice. These data support the long-term efficacy and safety of AAV gene therapy for hereditary antithrombin deficiency.

Longitudinal assessment of hemostatic adaptations in pregnant mares: Evidence of a physiological hypercoagulable state.

High-pressure excursions (HPE) during cardiopulmonary bypass (CPB) are rare but potentially life-threatening events linked to coagulation activation, inflammation. Known risk factors include male sex, large body surface area (BSA), elevated hematocrit (Htc), prior stroke and urgent surgery. Recommended management follows a stepwise approach involving haemodilution, heparin and antithrombin (AT), albumin or epoprostenol depending on Htc and pressure thresholds. We report a 69-year-old man undergoing urgent complex cardiac surgery who developed rising pre-oxygenator pressures 10 min after CPB initiation. Despite initial haemodilution and AT, pressures improved only partially. Administration of 100 mL of 20% albumin led to rapid normalization of pre-oxygenator and delta pressures, allowing safe continuation of CPB. The postoperative course was uneventful. Subsequent review of the oxygenator transmembrane resistance (R) showed a progressive decline following the administration of AT and albumin. This case suggests that AT, administered alongside albumin, may reduce blood viscosity and improve oxygenator performance. Further research is needed to clarify mechanisms and standardize management of HPE during CPB.

Novel SERPINC1 variants in hereditary antithrombin deficiency: first pathogenic deep-intronic variant, revealed by multiple genomic and transcriptomic approaches.

Post-hepatectomy liver failure (PHLF) remains a serious complication following liver resection, yet early prediction is an unmet clinical need. This prospective study enrolled 151 patients at elevated risk of PHLF (major hepatectomy, thrombocytopenia, or hyperbilirubinemia) and evaluated serum antithrombin III (ATIII) activity, measured preoperatively and on postoperative days (PODs) 1, 2, 3, and 5, as an early predictive marker. PHLF, diagnosed according to the International Study Group of Liver Surgery criteria, occurred in 35 patients (23.2%). ATIII activity was evaluated as raw values and as the percentage change from the preoperative baseline. Raw ATIII activity was significantly lower in the PHLF group at all time points (P < 0.001). The POD 3 ATIII decrease was significantly greater in the PHLF group (36% vs. 29%, P = 0.041). Multivariable logistic regression identified ATIII change from baseline ≥ 30% at POD 3 (odds ratio 3.04, P = 0.021), ALBI grade B (OR 2.77, P = 0.031), and ICG R-15 ≥ 15% (OR 3.50, P = 0.034) as independent risk factors for PHLF. The multivariable model demonstrated acceptable discriminative performance (apparent AUC 0.750; bootstrap-corrected AUC 0.730). These findings suggest that early postoperative decline in ATIII activity could serve as an early biomarker for identifying patients at increased risk of PHLF, potentially enabling timely intervention.

Risk stratification according to genotype and effect of thromboprophylaxis on obstetric outcomes in women with antithrombin deficiency

The interplay between inflammation and coagulation is a central driver of thrombotic risk across various diseases. While mathematical models of blood coagulation are well established, there remains a critical gap in quantitative frameworks that capture inflammation-induced hypercoagulability. In this study, we develop a mathematical model that explicitly simulates the interaction between pro-inflammatory cytokines and the coagulation cascade. The model incorporates key mechanisms, including: (i) upregulation of tissue factor (TF) by IL-1β, IL-6, and TNF-α; (ii) suppression of natural anticoagulants, namely antithrombin III (ATIII) and tissue factor pathway inhibitor (TFPI), by IL-6 and TNF-α; and (iii) feedback amplification of proinflammatory cytokines by thrombin. By encoding the bidirectional feedback between inflammatory and coagulation pathways, the model captures essential features of inflammation-driven hypercoagulability and enables systematic quantification of how variability in inflammatory extent and duration results in heterogeneous thrombin generation (TG) dynamics. To evaluate its effectiveness, we integrate the model with TG assays and apply it to virtual patient cohorts representing four clinically distinct conditions: COVID-19, sickle cell disease (SCD), type 2 diabetes mellitus (T2DM) and Hemophilia A. Model simulations predict that disease-specific inflammatory environments induce distinct shifts in TG dynamics. In COVID-19 and T2DM, elevated cytokine levels lead to shortened lag times and increased thrombin peak, whereas in SCD, shortened lag times are accompanied by a reduced thrombin peak. These effects are strongly modulated by both cytokine concentration and duration of exposure. These results demonstrate that the proposed computational model augments conventional TG assays by mechanistically linking inflammatory signaling to disease-specific coagulation responses. Collectively, the proposed computational framework extends conventional TG assays by considering the interplay between inflammation and coagulation, thereby providing a potential tool for predicting disease progression and identifying disease-specific therapeutic targets to advance personalized management strategies in thrombo-inflammatory disorders.

Antithrombin (AT) circulates as two distinct isoforms, alpha- and beta-AT, which differ in their glycosylation profiles; alpha-AT is fully glycosylated at positions Asn128, Asn167, Asn187, and Asn224, whereas beta-AT lacks Asn167 glycosylation. The ratio of alpha-AT/beta-AT is approximately 9:1 in plasma, with beta-AT being a stronger inhibitor due to its increased affinity for heparin. Post-transcriptional silencing of AT via fitusiran has been shown to efficiently ameliorate the hemostatic balance in hemophilia. In this study, we analyzed if and how fitusiran affected the distribution of alpha-AT and beta-AT. Using different experimental approaches (isoform-specific activity, antigen, and immunoprecipitation assays), we were able to distinguish beta-AT and alpha-AT. Fitusiran treatment reduced the total AT activity to less than 20% of normal in both F8 -/--mice and hemophilia A patients. Compared to controls, a 3.8- and 3.3-fold increase in the amount of beta-AT activity relative to residual total AT activity was detected in F8 -/--mice and fitusiran-treated patients, respectively (P < 0.0001). Furthermore, the ratio of beta-AT/total AT antigen levels increased 1.8-fold in the human patient samples (from 0.09 ± 0.03 to 0.16 ± 0.01; P = 0.003), which coincided with an increased intensity of the beta-AT band detected in immunoprecipitation assays. It is noteworthy that this increase in the beta-AT/total AT ratio significantly increased its anticoagulant potential. Finally, we measured beta-AT/total AT ratios also in unrelated pathologies: congenital AT deficiency and advanced liver cirrhosis. Both conditions were also associated with an up to twofold higher ratio of beta-AT/total AT. Altogether, our results demonstrate that reduced AT production modulates the ratio between beta-AT and alpha-AT.

Bridging laboratory assays, genetics, and clinical phenotypes in antithrombin deficiency: Rethinking the diagnostic paradigm.

Hypertension is a major risk factor for coronary artery disease (CAD) and contributes to a prothrombotic state. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) offer cardiovascular and renal benefits, but their effects on hypertension-related coagulation dysfunction remain unclear. This study assessed whether SGLT2is are associated with coagulation function in hypertensive CAD patients. This retrospective cohort study included 243 CAD patients, divided into four groups based on hypertension and SGLT2i treatment: HTN-SGLT2i (n = 56), HTN-non-SGLT2i (n = 74), non-HTN-SGLT2i (n = 50), and non-HTN-non-SGLT2i (n = 63). Coagulation markers were evaluated at baseline and after 1month. Two-way repeated measures ANOVAs and Scheirer-Ray-Hare tests were used to assess treatment-time interactions. Among hypertensive patients, SGLT2i use was associated with significant changes in coagulation parameters, including increased antithrombin III (AT-III) (p = 0.032), shortened prothrombin time (PT, p = 0.028), higher prothrombin activity (PTA, p = 0.004), reduced international normalized ratio (INR, p = 0.028), and decreased in D-dimer levels (p = 0.032). No significant changes observed in non-hypertensive patients. Significant interactions for AT-III, D-dimer, PT, PTA, and INR (all p < 0.05) support a hypertension-dependent effect. SGLT2is are associated with changes in coagulation profiles, including enhanced AT-III and reduced D-dimer levels, which may contribute to a lower thrombotic risk. Their lack of effect in normotensive individuals suggests a hypertension-specific mechanism, supporting further investigation into the antithrombotic benefits of SGLT2is in this population.

This study investigated the clinical significance of fetal umbilical artery (UA) and middle cerebral artery (MCA) Color Doppler parameters in the prenatal diagnosis of hypertensive disorder complicating pregnancy (HDCP) in pregnant women of advanced maternal age (AMA). AMA women with HDCP (245 gestational hypertension cases, 193 mild preeclampsia, 152 severe preeclampsia) and 80 healthy AMA pregnant women (control) in the late stage of singleton pregnancy were enrolled. Fetal UA and MCA Color Doppler parameters (systolic-to-diastolic ratio [S/D], pulsatility index [PI], and resistance index [RI]) were recorded. Influencing factors, and diagnostic and predictive value of these color Doppler parameters for HDCP and disease severity were assessed by logistic regression models and receiver operating characteristic curves. Total bilirubin, total protein (TP), creatinine, Cl-, and antithrombin III (AT-III) closely correlated with HDCP severity. Fetal UA S/D, PI, and RI values increased while MCA S/D, PI, and RI values decreased with the worsening of HDCP. Fetal UA S/D, MCA S/D, and MCA RI were independent influencing factors for HDCP occurrence, while fetal UA RI, MCA S/D, and MCA PI were independent influencing factors for HDCP severity. The combined detection of these parameters demonstrated superior predictive value for HDCP occurrence and severity than individual parameter detection. This study identifies several fetal UA and fetal MCA Color Doppler ultrasound parameters as potential influencing factors for HDCP occurrence and severity. The combined detection of these parameters may provide a reference for early recognizing HDCP and evaluating severity in women of AMA.

Traditional haemophilia therapies act to replace the relevant missing clotting factor, are not interchangeable between haemophilia A and B and cannot be used in patients with high titre inhibitors. Novel non-replacement factor therapies (NFT) target other endogenous coagulation proteins or anticoagulants such as antithrombin (AT) and tissue factor pathway inhibitor (TFPI) to rebalance haemostasis. As such, pharmaceutical clinical trials of these molecules have enrolled patients with haemophilia A or B, with and without inhibitors. The requirement for monitoring the efficacy of NFTs is greatly reduced compared to replacement therapy and global assays such as thrombin generation assay (TGA) have been used extensively in clinical trials to indicate improvement to haemostasis. Comprehensive haemophilia care, including access to and laboratory monitoring of replacement and NFTs, is well established in high income countries, but there are profound global inequities in the diagnosis and treatment of haemophilia which still need to be remedied. The authors examine the challenges of haemophilia and von Willebrand diagnosis and monitoring of NFTs using conventional and global assays of haemostasis.

Antithrombin III as a potentially predictive biomarker for post-stroke depression.

Identification of new molecular mechanisms of antithrombin deficiency: six new SERPINC1 variants in a Polish cohort.

ABSTRACTObjective:To evaluate the predictive value and clinical utility of thrombelastography (TEG) combined with coagulation parameters for adverse pregnancy outcomes(APOs).Methodology:A retrospective analysis was conducted on the clinical data of 186 pregnant women admitted to the Department of Obstetrics in Affiliated Hospital of Chengde Medical College between January 2022 and June 2025. Based on pregnancy outcomes, patients were classified into the APO group and the normal pregnancy outcome group. Baseline characteristics, TEG parameters, and coagulation parameters were compared between groups. Pearson correlation analysis was performed to assess associations between TEG and coagulation parameters in the APO group.Results:No significant differences were observed between the two groups in baseline characteristics such as age, gravidity, parity, and gestational weight gain (all P > 0.05), indicating comparability. Regarding TEG parameters, the APO group showed lower R values and higher maximum amplitude (MA) and coagulation index (CI) values compared with the normal outcome group (P < 0.05, respectively). For coagulation parameters, fibrinogen (FIB) and D-dimer (D-D) levels were significantly elevated, while antithrombin III (AT-III) levels were decreased in the APO group (P < 0.05, respectively).Conclusion:The combination of TEG and coagulation parameters demonstrates higher predictive efficiency for APOs than either method alone, providing a reliable basis for the early identification of high-risk populations and guiding clinical intervention strategies.

Congenital antithrombin (AT) deficiency, primarily caused by SERPINC1 variants, is a major risk factor for venous thromboembolism (VTE). We previously reported the SERPINC1 p.M313T variant in three VTE probands with normal AT activity and antigen levels. This study aims to elucidate its pathogenetic mechanism.Thrombin generation test (TGT), thermal stability, native-urea PAGE, in vitro protein expression, and enzymatic assays were performed. Glycosylation analysis was conducted using glycosidase treatment, and structural analysis was performed through molecular dynamics simulation.AT in probands' plasma samples exhibited reduced thermostability and increased proportions of denatured and latent forms compared with normal pooled plasma. The recombinant AT-M313T protein exhibited increased inhibitory activity, consistent with findings in proband plasma based on AT activity and TGT. Despite this enhanced activity, the mutant protein demonstrated reduced thermostability and a marked tendency to transition into the latent form, potentially predisposing carriers to thrombosis under stress conditions. These characteristics may result from the introduction of abnormal O-linked glycosylation within the breach region, confirmed in both plasma-derived and recombinant AT. Molecular dynamics simulation revealed a less compact structure, with increased spacing in the shutter region and enhanced flexibility of the reactive center loop.The SERPINC1 p.M313T variant exhibits dual characteristics of high inhibitory activity and low structural stability, which together contribute to the transient AT deficiency. These findings suggest that AT deficiency may be underdiagnosed and highlight the importance of integrating techniques such as native-urea PAGE into standard diagnostic workflows to identify variants associated with structural abnormalities.

BACKGROUND: Inherited antithrombin deficiency (ATD), a rare autosomal dominant disorder due to SERPINC1 gene mutations, is the most severe inherited thrombophilia. Limited literature exists that focuses on ATD and its mutations in the Chinese population. This study aimed to characterize SERPINC1 gene mutations in a Chinese cohort and to explore their relationship with thrombophilia. METHODS: Coagulation screening results and clinical data were meticulously collected from 23 unrelated probands with ATD and their family members. Genomic DNA was extracted and subjected to PCR amplification and direct sequencing. Putative mutations were analyzed using in silico bioinformatic tools. Mutant antithrombin (AT) proteins were expressed in HEK293 cells, and ELISA was used to detect wild-type and mutant AT. RT-qPCR was used to measure AT mRNA expression in transfected cells. RESULTS: Among the 23 probands, 15 (65.2%) exhibited concurrent reductions in both AT: A and AT: Ag (type I defects), while the remaining 8 (34.8%) had normal AT: Ag levels (type II defects). Genetic analysis revealed a spectrum of 21 distinct mutations across 87.0% (20/23) of the probands. Most were point mutations predicted to be deleterious and were primarily located in exons 5 and 3. Among the 20 mutation carriers, 15 (75%) were heterozygous and most of them experienced thrombosis with identifiable triggers. The other 5 (25%) were compound heterozygous and primarily presented with spontaneous thrombosis. Notably, the missense mutations c.1346T > A and c.442T > C were recurrent. These mutations exhibited high heterogeneity, with no ethnic-specific mutations observed. In vitro expression confirmed that synthesis and/or secretion defects in the mutant proteins are the primary mechanism underlying the antithrombin deficiency. CONCLUSIONS: SERPINC1 gene analysis benefits asymptomatic family members, especially child-bearing women, by informing venous thromboembolism prevention strategies and guiding anticoagulant choice in cases involving heparin-binding site mutations. This underscores the essential role of genetic diagnosis in ATD management.

A bstract Cerebral venous sinus thrombosis (CVST) is an uncommon but potentially life-threatening cause of pediatric stroke. Inherited thrombophilias play a significant role in children with CVST, particularly in severe or recurrent cases. Antithrombin III (AT-III) deficiency, most often caused by mutations in SERPINC1 gene, is a rare but highly thrombogenic condition, with cerebral venous thrombosis being an infrequent presentation. Here, we report a case of a 16-year-old previously healthy male who presented with progressive headache and generalized tonic–clonic seizures, followed by rapid neurological deterioration. Neuroimaging revealed hemorrhagic venous infarction with extensive sinus thrombosis. Thrombophilia evaluation demonstrated mildly reduced antithrombin activity. Despite decompressive craniectomy and anticoagulation, the patient developed recurrent, extensive CVST during perioperative interruption of anticoagulation, with new hemorrhagic infarcts. Genetic testing identified heterozygous SERPINC1 mutation classified as a variant of uncertain significance, in the setting of reduced antithrombin activity and recurrent thrombosis. The patient was stabilized on long-term anticoagulant and discharged with plans for lifelong anticoagulation and genetic counseling. CVST due to AT-III deficiency is rare, and recurrent, malignant CVST requiring neurosurgical intervention is exceedingly uncommon. This case highlights the aggressive thrombotic phenotype associated with SERPINC1 mutations and underscores the importance of early thrombophilia screening and genetic confirmation in pediatric patients with severe or recurrent CVST. Identification of AT-III deficiency has critical therapeutic implications, including anticoagulation strategy, potential heparin resistance, and the need for long-term management and family screening. Inherited AT-III deficiency should be considered in adolescents with recurrent or extensive CVST. Early diagnosis and tailored anticoagulation can improve outcomes and prevent recurrence.

AT and PC are key components of the anticoagulant system. Mutations in their encoding genes, SERPINC1 and PROC, can lead to insufficient protein levels or impaired function, thereby increasing an individual's susceptibility to venous thromboembolism (VTE). In this study, we describe the clinical characteristics and functional effects of compound heterozygous mutations in SERPINC1 and PROC in two pedigrees. Anticoagulant protein activity and antigen levels were evaluated in family members. Targeted sequencing was performed using next-generation sequencing (NGS) and CNVplex technology. The identified variants were assessed for evolutionary conservation, pathogenic potential, and their impact on protein structure. Thrombin generation was measured using the calibrated automated thrombogram (CAT) assay. The PC:A and PC:Ag of proband 1 were decreased to 57% and 59.2%, and PC:A of proband 2 was decreased to 68%. The SERPINC1 (OMIM#:613118) and PROC (OMIM#:176860) gene analysis indicated that there were c.400+5G>A and c.883G>A in proband 1, c.811C>T and c.880C>T in proband 2, respectively. These mutation sites are highly conserved across homologous species. Bioinformatics analysis predicts their potential pathogenicity, suggesting that they may alter the three-dimensional structures of both AT and PC proteins, thereby compromising their functional integrity. Thrombin generation assays revealed that two AT mutation carriers exhibited varying degrees of elevated ETP. In the presence of sTM, two PC mutation carriers showed significantly impaired plasma anticoagulant function without a significant reduction in thrombin generation. In both pedigrees, we identified two distinct mutations in AT and PC. Dual mutations in SERPINC1 and PROC confer markedly increased VTE susceptibility.

Thrombosis underlies many life-threatening cardio-cerebrovascular diseases. Although existing anticoagulants are effective in treating thrombotic diseases, their application is limited due to the concern of bleeding. New anticoagulants that preserve hemostasis have significant clinical importance. Herein, a novel galactosylated glycosaminoglycan, with unique sequence and sulfate substitutions, was isolated from the snail Camaena cicatricose (CCG). Administration of CCG effectively inhibited thrombus formation in a rat venous thrombosis model, which is positively correlated with its ex vivo anticoagulant activity (APTT prolongation), with much lower bleeding risk compared with heparins. It is also effective in preventing thrombosis in the rat arterial-venous shunt model and endotoxin-treated mice. CCG inhibited coagulation by selectively targeting iFXase enzyme complex (FIXa-FVIIIa), in an antithrombin (AT)-independent manner. CCG can bind to FIXa with high affinity and decrease the affinity of FIXa-FVIIIa, with no effect on the FIXa activity. Compared with heparins, it cannot bind to AT and exhibits high selectivity for iFXase inhibition, consistent with its absence of the specific heparin pentasaccharide sequence. Overall, the snail galactosed glycosaminoglycan inhibits thrombosis without affecting hemostasis via disrupting iFXase (FIXa-FVIIIa). CCG may represent a promising candidate for thrombosis treatment without increased bleeding risk.