In vivo thrombin activity in the diatom Phaeodactylum tricornutum: biotechnological insights.

Diatoms are responsible for 20% of global carbon dioxide fixation and have significant potential in various biotechnological and industrial applications. Recently, the pennate diatom Phaeodactylum tricornutum has emerged as a prominent platform organism for metabolic engineering and synthetic biology. The availability of its genome sequence has facilitated the development of new bioengineering tools. In this study, we used in silico analyses to identify sequences potentially encoding thrombin-like proteins, which are involved in recognizing and cleaving the thrombin sequence LVPRGS in P. tricornutum. Protein structure prediction and docking studies indicated a similar active site and ligand positioning compared to characterized human and bovine thrombin. The evidence and efficiency of the cleavage were determined in vivo using two fusion-protein constructs that included YFP to measure expression, protein accumulation, and cleavage. Western blot analysis revealed 50-100% cleavage between YFP and N-terminal fusion proteins. Our findings suggest the existence of a novel thrombin-like protease in P. tricornutum. This study advances the application of diatoms for the synthesis and production of complex proteins and enhances our understanding of the functional role of these putative thrombin sequences in diatom physiology. KEY POINTS: • Protein structure predictions reveal thrombin-like active sites in P. tricornutum. • Validated cleavage efficiency of thrombin-like protease on fusion proteins in vivo. • Study advances bioengineering tools for diatom-based biotechnological applications.

Structure-based virtual screening towards the discovery of novel thrombin inhibitors with Anti-HCC activities.

Introduction: Hepatic carcinoma (HCC) is one of the most lethal malignant tumors in the world, and new treatment regimens for this disease are urgently needed. Studies have shown that thrombin stimulates tumor progression by forming fibrin and activating platelets. Dabigatran etexilate, a thrombin inhibitor, can inhibit the activity of thrombin and prevent the proliferation and metastasis of HCC in cells and nude mice. Methods: The present study was designed to find thrombin inhibitors with novel skeletons, and further confirm the correlation between thrombin inhibition and HCC prevention to identify potential anti-HCC drug leads. Results and Discussion: The potential thrombin inhibitors were firstly screened in the Topscience Database, and 20 potential active molecules were found by molecular docking. The effect of these molecules on thrombin inhibition, coagulation and tumor proliferation were evaluated, and the definite activity of ZXX-4 was identified. Further in vivo assays in nude mice showed that ZXX-4 inhibited tumor proliferation in nude mice, reduced tumor metastasis, and enhanced the clinical efficacy of first-line drug sorafenib for the treatment of HCC. ZXX-4 can be further explored as an anti-tumor lead compound with a novel skeleton, and inhibition of thrombin can serve as a potential treatment strategy for HCC.

Bivalirudin as an anticoagulation strategy for acute hemodialysis in children: Two cases with a summary of recent literature.

Unfractionated heparin is the most used anticoagulative agent for extracorporeal settings in children, including acute hemodialysis modalities. In certain situations, such as heparin-induced thrombocytopenia, alternatives must be applied. The direct thrombin inhibitor bivalirudin has come forth as an attractive substitute. Bivalirudin is currently only approved for adult use in specific percutaneous coronary intervention settings. However, it has a growing off-label popularity in different contexts for both adult and pediatric patients. Experience with bivalirudin in children is mainly limited to extracorporeal membrane oxygenation, ventricular assist devices and during cardiopulmonary bypass surgery. Literature about its use as anticoagulation strategy for pediatric hemodialysis is very scarce. Here, we present two pediatric cases where bivalirudin was used during acute hemodialysis, followed by a short summary of recent literature.

Application of fibrin-based biomaterial for human ovarian tissue encapsulation and cryopreservation as alternative approach for fertility preservation.

This study aimed to investigate the effects of fibrin-based hydrogel encapsulation, with or without vascular endothelial growth factor (VEGF), on follicle quality and cell survival signaling pathways after ovarian tissue cryopreservation. Ovarian cortex donated by seven patients (ages 44-47 years old) was divided into four groups: I) fresh control, II) ovarian tissue without encapsulation (non-FT), III) fibrin (10 mg/mL fibrinogen plus 50 IU/mL thrombin; 10FT) encapsulated tissue without VEGF, and IV) encapsulated tissue with 0.1 µg/mL VEGF (10FT-VEGF), followed by a slow freezing process. Evaluation criteria included normal follicle morphology, density, cell proliferation, apoptosis, and metabolism signaling pathways (BAX/BCL-2 ratio, CASPASE-3 and 9, ATP-6 genes, VEGF-A, and ERK-1/2 protein expression levels). Major outcomes revealed that the percentages of morphologically normal follicles and density were significantly decreased by cryopreservation. Ovarian tissue encapsulation using the 10FT formulation (with or without VEGF) could maintain the ERK-signaling cascade, which was comparable to the fresh control. Among the frozen-thawed cohorts, the BAX/BCL-2 ratio, CASPASE-3, CASPASE-9, and ATP-6 expression levels were unfavorable in the non-FT group. However, statistically different results, including VEGF-A expression levels, were not detected. Collectively, our present data demonstrated the first applicable biomaterial matrix for human ovarian tissue encapsulation which might create an optimal intra-ovarian cortex environment during cryopreservation. Further studies to optimize hydrogel polymerization should be expanded, given the potential benefits for cancer patients who wish to preserve fertility through ovarian tissue cryopreservation.

Aptamer biosensors for thrombin.

Thrombin, a key factor in the coagulation cascade, is a valuable biomarker of great importance for the prognosis, diagnosis, and monitoring of various diseases, including cancer and heart disease. Due to the increasing attention to the development of point-of-care testing (POCT) options, various types of biosensors have been invented to enhance the accuracy and speed of detection of important biomarkers such as thrombin. Implementation of aptamers in biosensors (aptasensors) improves the target recognition capacity due to the high-affinity binding nature of aptamers. Herein, this review presents recent studies of aptasensors for thrombin detection based on different detection mechanisms encompassing optical biosensors, surface-enhanced Raman spectroscopy (SERS), electrochemical detection, piezoelectric detection, and lateral flow assay.

Decreased Protein C Pathway Activity in COVID-19 Compared to Non-COVID Sepsis: An Observational and Comparative Cohort Study.

Sepsis-associated coagulopathy increases risk of mortality. Impairment of the anticoagulant protein C (PC) pathway may contribute to the thrombotic phenotype in coronavirus disease 2019 (COVID-19) sepsis. This study assessed the functionality of this pathway in COVID-19 and non-COVID sepsis by measuring its key enzymes, thrombin and activated PC (APC). The study population included 30 patients with COVID-19, 47 patients with non-COVID sepsis, and 40 healthy controls. In healthy controls, coagulation activation and subsequent APC formation was induced by 15 µg/kg recombinant activated factor VII one hour before blood sampling. APC and thrombin in plasma were measured using oligonucleotide-based enzyme capture assays. The indirect thrombin markers prothrombin-fragment 1+2 (F1+2) and thrombin-antithrombin complex (TAT) were also measured. Compared with stimulated healthy controls, median thrombin, F1+2, and TAT levels were higher in patients with COVID-19 (up to 6-fold, p < 2 × 10-6) and non-COVID sepsis (up to 4.7-fold, p < 0.010). APC levels were 2.4-fold higher in patients with COVID-19 (7.44 pmol/L, p = 0.011) and 3.4-fold higher in non-COVID sepsis patients (10.45 pmol/L, p = 2 × 10-4) than in controls (3.08 pmol/L). Thrombin markers and APC showed correlation in both COVID-19 (r = 0.364-0.661) and non-COVID sepsis patients (r = 0.535-0.711). After adjustment for PC levels, median APC/thrombin, APC/F1+2, and APC/TAT ratios were 2-fold (p = 0.036), 6-fold (p = 3 × 10-7) and 3-fold (p = 8 × 10-4) lower in the COVID-19 group than in the non-COVID sepsis group, and the latter two were also lower in the COVID-19 group than in stimulated healthy controls. In conclusion, it was found that a comparatively lower anticoagulant APC response in COVID-19 patients as compared to non-COVID sepsis patients, potentially linked to endothelial dysfunction, contributes to the prothrombotic phenotype of COVID-19 sepsis.

Protease activated receptor-1 regulates mixed lineage kinase-3 to drive triple-negative breast cancer tumorigenesis.

Triple-negative breast cancer (TNBC) is difficult to treat breast cancer subtype due to lack or insignificant expressions of targetable estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2). Therefore, finding a targetable protein or signaling pathway in TNBC would impact patient care. Here, we report that a member of the Mixed Lineage Kinase (MLK) family, MLK3, is an effector of G-protein-coupled protease-activated receptors 1 (PAR1) and targeting MLK3 by a small-molecule inhibitor prevented PAR1-mediated TNBC tumorigenesis. In silico and immunohistochemistry analysis of human breast tumors showed overexpression of PAR1 and MLK3 in TNBC tumors. Treating α-thrombin and PAR1 agonist increased MLK3 and JNK activities and induced cell migration in TNBC cells. The PAR1 positive/high (PAR1+/hi) population of TNBC cells showed aggressive tumor phenotype with increased MLK3 signaling. Moreover, combined inhibition of the PAR1 and MLK3 mitigated the TNBC tumor burden in preclinical TNBC models. Our data suggests that activation of the PAR1-MLK3 axis promotes TNBC tumorigenesis. Therefore, combinatorial therapy targeting MLK3 and PAR1 could effectively reduce TNBC tumor burden.

ErpY-like Protein Interaction with Host Thrombin and Fibrinogen Intervenes the Plasma Coagulation through Extrinsic and Intrinsic Pathways.

The survival and proliferation of pathogenic Leptospira within a host are complex phenomena that require careful consideration. The ErpY-like lipoprotein, found on the outer membrane surface of Leptospira, plays a crucial role in enhancing the bacterium's pathogenicity. The rErpY-like protein, in its recombinant form, contributes significantly to spirochete virulence by interacting with various host factors, including host complement regulators. This interaction facilitates the bacterium's evasion of the host complement system, thereby augmenting its overall pathogenicity. The rErpY-like protein exhibits a robust binding affinity to soluble fibrinogen, a vital component of the host coagulation system. In this study, we demonstrate that the rErpY-like protein intervenes in the clotting process of the platelet-poor citrated plasma of bovines and humans in a concentration-dependent manner. It significantly reduces clot density, alters the viscoelastic properties of the clot, and diminishes the average clotting rate in plasma. Furthermore, the ErpY-like protein inhibits thrombin-catalyzed fibrin formation in a dose-dependent manner and exhibits saturable binding to thrombin, suggesting its significant role in leptospiral infection. These findings provide compelling evidence for the anticoagulant effect of the ErpY-like lipoprotein and its significant role in leptospiral infection.

The Contrasting Effects of Bothrops lanceolatus and Bothrops atrox Venom on Procoagulant Activity and Thrombus Stability under Blood Flow Conditions.

BACKGROUND: Consumption coagulopathy and hemorrhagic syndrome are the typical features of Bothrops sp. snake envenoming. In contrast, B. lanceolatus envenoming can induce thrombotic complications. Our aim was to test whether crude B. lanceolatus and B. atrox venoms would display procoagulant activity and induce thrombus formation under flow conditions. METHODS AND PRINCIPAL FINDINGS: Fibrin formation in human plasma was observed for B. lanceolatus venom at 250-1000 ng/mL concentrations, which also induced clot formation in purified human fibrinogen, indicating thrombin-like activity. The degradation of fibrinogen confirmed the fibrinogenolytic activity of B. lanceolatus venom. B. lanceolatus venom displayed consistent thrombin-like and kallikrein-like activity increases in plasma conditions. The well-known procoagulant B. atrox venom activated plasmatic coagulation factors in vitro and induced firm thrombus formation under high shear rate conditions. In contrast, B. lanceolatus venom induced the formation of fragile thrombi that could not resist shear stress. CONCLUSIONS: Our results suggest that crude B. lanceolatus venom displays amidolytic activity and can activate the coagulation cascade, leading to prothrombin activation. B. lanceolatus venom induces the formation of an unstable thrombus under flow conditions, which can be prevented by the specific monovalent antivenom Bothrofav®.

Assessment of Platelet Aggregation and Thrombin Generation in Patients with Familial Chylomicronemia Syndrome Treated with Volanesorsen: A Cross-Sectional Study.

BACKGROUND: The antisense oligonucleotide against APOC3 mRNA volanesorsen was recently introduced to treat Familial Chylomicronemia Syndrome (FCS). Cases of decreased platelet count are reported among patients treated with volanesorsen. The aim of the study was to evaluate platelet function and thrombin generation (TG) assessment in FCS patients receiving volanesorsen. We performed a cross-sectional study on FCS patients treated with volanesorsen. METHODS: Changes in platelet count PLC were assessed from baseline to Tw12 and Tw36. To assess TG, samples were processed by CAT (with PPP-reagent LOW). The results were expressed by the thrombogram graphic (thrombin variation over time); LagTime; endogenous thrombin potential (ETP); peak; time to reach peak (ttpeak), StartTail and Velocity Index. Platelet aggregation was assessed by testing different agonists using the turbidimetry method. RESULTS: Four FCS patients and four matched healthy controls were included in the present study. Changes in PLC were 30% at Tw12 and 34% at Tw36. Thrombin generation results showed values in the normal range (for patients and controls, respectively, LagTime:10.42 ± 4.40 and 9.25 ± 0.99; ttPeak:14.33 ± 4.01 and 13.10 ± 0.67; StartTail: 32.13 ± 3.54 and 29.46 ± 1.69; Velocity Index: 20.21 ± 3.63 and 33.05 ± 13.21; ETP: 599.80 ± 73.47 and 900.2 ± 210.99; peak value: 76.84 ± 1.07 and 123.30 ± 39.45) and no significant difference between cases and controls. Platelet aggregation test showed values in range, with no significant difference compared to healthy controls. CONCLUSIONS: Our study showed for the first time that no significant changes in general hemostasis assessed by TG and in platelet function were observed in FCS patients receiving volanesorsen.

Heparin resistance management during cardiac surgery: a literature review and future directions.

INTRODUCTION: Heparin, a commonly used anticoagulant in cardiac surgery, binds to antithrombin III (ATIII) to prevent clot formation. However, heparin resistance (HR) can complicate surgical procedures, leading to increased thromboembolic risks and bleeding complications. Proper diagnosis and management of HR are essential for optimizing surgical outcomes. METHODOLOGY: Diagnosis of HR involves assessing activated clotting time (ACT) and HR assays. Management strategies were identified through a comprehensive review of the literature, including studies exploring heparin dosage adjustments, antithrombin supplementation, and alternative anticoagulants in cardiac surgery patients with HR. A thorough search of relevant studies on HR was conducted using multiple scholarly databases and relevant keywords, resulting in 59 studies that met the inclusion criteria. DISCUSSION: HR occurs when patients do not respond adequately to heparin therapy, requiring higher doses or alternative anticoagulants. Mechanisms of HR include AT III deficiency, PF4 interference, and accelerated heparin clearance. Diagnosis involves assessing ACT and HR assays. HR in cardiac surgery can lead to thromboembolic events, increased bleeding, prolonged hospital stays, and elevated healthcare costs. Management strategies include adjusting heparin dosage, supplementing antithrombin levels, and considering alternative anticoagulants. Multidisciplinary management of HR involves collaboration among various specialities. Strategies include additional heparin doses, fresh frozen plasma (FFP) administration, and antithrombin concentrate supplementation. Emerging alternatives to heparin, such as direct thrombin inhibitors and nafamostat mesilate, are also being explored. CONCLUSION: Optimizing the management of HR is crucial for improving surgical outcomes and reducing complications in cardiac surgery patients. Multidisciplinary approaches and emerging anticoagulation strategies hold promise for addressing this challenge effectively.

Modulating Coagulation via Bioinspired Mesoporous Calcium-Decorated Silica Nanoparticles for Efficient Fibrin Clot Formation.

Blood clotting is vital for preventing bleeding after an injury. Hemostasis is a complex cascade involving numerous plasma proteins. Uncontrolled bleeding leads to mortality. The presence of Ca (calcium) activates and promotes the different phases in the coagulation cascade. Even nonbiological surfaces such as silicates may activate coagulation factor XII (FXII). This causes the clotting of the blood. The exceptional hemostatic ability of the mesoporous calcium-decorated silica nanoparticles (MCSNs) is achieved by stimulating the factors needed to form fibrin mesh, a durable clot, thereby establishing hemostasis. This may be used as a hemostatic agent during an accident surgical procedure and other bleeding-related trauma conditions. This study investigates the mechanistic activation of the coagulation cascade by MCSN through blood coagulation index, clotting time, and coagulation activation studies like PT and aPTT. Our finding demonstrates that MCSN induces platelet adhesion and RBC aggregation and activates thrombin generation through distinct pathways.

Pseudoaneurysm in the Axillary Tail of the Breast After A Core Needle Biopsy.

We present the case of a forty-year-old asymptomatic female with no personal or family history of breast cancer, who underwent a core needle biopsy (CNB) following the identification of a focal asymmetry in the right breast on screening mammography. Eight months later, a prominent adjacent vascular structure with a round outpouching was detected on breast ultrasound, confirmed as a post-biopsy pseudoaneurysm. Breast pseudoaneurysms, although exceedingly rare, result from inadvertent vessel puncture during core needle biopsies, particularly when larger gauge needles are used. They present as palpable, throbbing lumps in the breast and are well-defined heterogeneous structures that exhibit turbulent flow with a feeding artery on color Doppler imaging. This swirling sign showing a to-and-fro waveform is also known as the "yin-yang" sign on Doppler ultrasound. Post-CNB pseudoaneurysms in the breast, while rare, should be considered as potential complications following core need biopsy. Understanding their characteristic imaging features, risk factors, and available management options is essential for early diagnosis and appropriate treatment. This case underscores the importance of vigilance in biopsy procedures and the need for prompt recognition and intervention in case of such complications.

UPLC-Q-TOF-MS.

INTRODUCTION: Peach kernel (PK), one of the medicinal and edible plants, has been widely used in the treatment of clinical thrombotic diseases and exhibited great therapeutic effects. However, the effective substances and targets are still obscure. METHODS: A method consisting of affinity ultrafiltration (AUF) coupled with ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectroscopy (UPLC-Q-TOF-MS) was established to rapidly screen active components that inhibit thrombin, a key mediator in coagulation cascade. The binding energy and sites were analyzed by molecular docking to evaluate the binding capacity of thrombin-ligand complexes, and the thrombin inhibitory activity of screened ligands was further validated via in vitro and in vivo tests. RESULTS: two potential thrombin ligands (L-arginine and cytidine) were screened by AUF-HPLC and identified by UPLC-Q-TOF-MS. The ligands with anti-thrombin structure exhibited great affinity with thrombin. The anticoagulant bioactivity of ligands was validated by a significant reduction in thrombosis in zebrafish tails and the potential mechanism could be related to direct inhibition of thrombin. CONCLUSION: The systematic screening of anti-thrombin active components in PK based on AUF-UPLC-Q-TOF-MS is a feasible and effective method, providing valuable information for the future development of direct thrombin inhibitors.

Ultrasound-guided percutaneous thrombin injection for the management of upper extremity pseudoaneurysms: 20 years of tertiary care center experience.

PURPOSE: To evaluate the safety and efficacy of ultrasound-guided percutaneous thrombin injection for the treatment of upper extremity pseudoaneurysms. METHODS: An institutional database containing 8,316,467 radiology reports was searched for suitable cases over a 241-month period. Fourteen female and 10 male patients, average age of 69.7 years (range 29-93) underwent a total of 26 procedures for the management of upper extremity pseudoaneurysms, involving the radial (n = 9), brachial (n = 9) or other upper extremity arteries (n = 6). Baseline demographic and pseudoaneurysm characteristics were documented, together with primary and secondary success, failures, and complications. All procedures were performed with real-time ultrasound guidance. RESULTS: The mean pseudoaneurysm volume was 9.93 cm3 (range 0.06-111.62 cm3). Twelve cases were related to central line placement or arterial access. Primary success was obtained in 50% (n = 12) after a single ultrasound-guided thrombin injection, and secondary success was achieved in an additional six (for a total success of 75%). Success was highest for the treatment of brachial artery pseudoaneurysms (87.5%), and in those who were diagnosed within 7 days of the inciting event, findings that were statistically significant (p-value 0.046 and 0.002, respectively). CONCLUSIONS: Ultrasound-guided percutaneous thrombin injection is safe and effective for managing upper extremity pseudoaneurysms.

Newly diagnosed multiple myeloma with bleeding and coagulation abnormalities caused by a thrombin-inhibiting substance.

Approximately 7% of patients with newly diagnosed multiple myeloma (MM) experience bleeding complications with varying causes, but few reports have described these complications. Here we report the case of a patient with newly diagnosed MM who presented with a bleeding tendency and various coagulation abnormalities. Chromogenic assays, thrombin time, and reptilase time revealed the presence of a thrombin-inhibiting substance that inhibited release of fibrinopeptide A from fibrinogen. The coagulation abnormalities improved after treatment with daratumumab, lenalidomide, and dexamethasone. As the thrombin inhibition mechanism remains unclear, no previous studies have reported recent treatment outcomes in older patients producing thrombin-inhibiting substances, which can hinder clinical treatment. Therefore, we believe that the diagnosis and the treatment course of this case provide valuable information. Moreover, such case reports provide significant insights into the pathophysiology of bleeding complications associated with MM.

A highly sensitive and specific fluorescent probe for thrombin detection and high-throughput screening of thrombin inhibitors in complex matrices.

Thrombin plays a critical role in hemostasis and hemolysis, and is a significant biomarker for blood-related diseases. Detection and inhibitors screening of thrombin are essential in medical research. In this study, we developed a fluorescent sensor based on the interaction between quantum dots (QDs) and fibrinogen (Fib) for thrombin detection and its inhibitors screening. Upon the presence of thrombin, the fibrinogen of soluble QDs-Fib were converted into insoluble fibrin precipitate, causing a change of fluorescence intensity in the supernatant. Under optimized conditions, our method exhibited an excellent linearity (R2 ≥0.99) over the range of 2∼100 U/L with a limit of detection (LOD) as low as 0.29 U/L. Moreover, we employed this method to screen for thrombin inhibitors using dabigatran as an exemplary direct thrombin inhibitor (DTI), even at concentrations as low as 1 nM. Finally, the established method was successfully used to screen thrombin inhibitors in 23 different extracts from Eupolyphaga sinensis walker. The method provided not only a sensitive, specific and high throughput assay for the detection of thrombin activity in biological samples, but also a reliable strategy for the screening of thrombin inhibitors in complex matrices.

A single-center study of reference intervals for TAT, PIC, TM and t-PAIC in healthy older Chinese adults.

OBJECTIVE: To explore the distribution of thrombin-antithrombin complex (TAT), plasmin-α2-antiplasmin inhibitor complex (PIC), thrombomodulin (TM), and tissue plasminogen activator-inhibitor complex (t-PAIC) in healthy older Chinese adults, and establish the reference intervals (RIs). METHODS: The Biotech Shine i2900 chemiluminescence immune assay was used to measure the plasma concentrations of TAT, PIC, TM, and t-PAIC in 1628 adults ≥ 60 years. The RIs were established using the 2.5th and 97.5th percentiles of the distribution. RESULTS: TAT levels were lower in males than females across all ages. Differences between the ages of 60-79 and ≥ 80 in both sex groups were statistically significant, with an upward trend with age. PIC levels showed no difference between the sexes but increased with age in both groups. TM levels did not differ between the sex groups, with slight fluctuation with age. The level in females aged 60-69 was slightly higher than that in the other groups; the difference was statistically significant. T-PAIC levels were not significantly different between the sex groups, with less fluctuation with sex and age. The level in males ≥ 80 years old was slightly lower than that in the other groups; the difference was statistically significant. The RIs for all markers in healthy older Chinese adults were determined and statistically reported by age and sex. For TAT, the RIs for males aged 60-79 and ≥ 80 are 0.51-2.30 ng/mL and 0.88-3.72 ng/mL, respectively, whereas for females aged 60-79 and ≥ 80, the RIs are 0.68-2.82 ng/mL and 1.02-3.67 ng/mL, respectively. For PIC, the RIs for the age groups 60-69, 70-79, and ≥ 80 are 0.10-0.89 µg/mL, 0.12-1.00 µg/mL, and 0.21-1.04 µg/mL, respectively. The RI of TM for females aged 60-69 is 3.32-13.22 TU/mL, whereas it is 2.96-13.26 TU/mL for the other groups. The RI of t-PAIC for males aged ≥ 80 is 1.63-10.68 ng/mL, whereas it is 2.33-11.34 ng/mL for the other groups. CONCLUSIONS: Discrepancies exist in thrombus markers among different sex and age groups. The RIs of TAT, PIC, TM and t-PAIC for healthy older Chinese adults were successfully established.

Spontaneous bleeding in chronic kidney disease: global coagulation assays may predict bleeding risk.

Background: Chronic kidney disease (CKD) is associated with increased bleeding and thrombotic risks. Standard blood tests do not sufficiently quantify these risks. Global coagulation assays (GCAs) provide a more comprehensive assessment of coagulation. Objectives: We aimed to evaluate if GCAs are predictive of spontaneous major bleeding (sMB) in CKD. Methods: Adult patients with CKD (estimated glomerular filtration rate, <30 mL/min/1.73m2) were recruited to this pilot prospective observational study. Testing with GCAs (thromboelastography, overall hemostatic potential, calibrated automated thrombogram, and plasminogen activator inhibitor-1) was performed, and the results were correlated to sMB events. Results: Eighty-seven CKD patients (median age, 67 years; 67.8% male) were included, with median follow-up of 3.1 years. CKD patients demonstrated elevated fibrinogen, factor VIII, and von Willebrand factor antigen levels, while other conventional coagulation test results were within reference intervals. Ten episodes of sMB (11.5%) were captured (3.0/100 person-years), with no significant association demonstrated between sMB and antiplatelet use (P = .36), platelet count (P = .14), or renal function (urea, P = .27; estimated glomerular filtration rate, P = .09). CKD patients with sMB had more hypocoagulable GCA parameters compared with those without sMB. The lowest quartiles of endogenous thrombin potential (subhazard ratio [sHR], 7.11; 95% CI, 1.84-27.45), overall hemostatic potential (sHR, 6.81; 95% CI, 1.77-26.16), and plasminogen activator inhibitor-1 (sHR, 5.26; 95% CI, 1.55-17.91) were associated with sMB. Conclusion: This pilot study demonstrates that GCAs such as thrombin and fibrin generation may predict sMB risk in patients with CKD, which has potential to be practice-changing. Larger studies are required to validate these findings.