New High-Affinity Thrombin Aptamers for Advancing Coagulation Therapy: Balancing Thrombin Inhibition for Clot Prevention and Effective Bleeding Management with Antidote

Abstract

Thrombin is a key enzyme involved in blood clotting, and its dysregulation can lead to thrombotic diseases such as stroke, myocardial infarction, and deep vein thrombosis. Thrombin aptamers have the potential to be used as therapeutic agents to prevent or treat thrombotic diseases. Thrombin DNA aptamers developed in our laboratory exhibit high affinity and specificity to thrombin. In vitro assays have demonstrated their efficacy by significantly decreasing Factor II activity and increasing PT and APTT times in both plasma and whole blood. Aptamers AYA1809002 and AYA1809004, the two most potent aptamers, exhibit high affinity for their target, with affinity constants (Kd) of 10 nM and 13 nM, respectively. Furthermore, the in vitro activity of these aptamers displays dose-dependent behavior, highlighting their efficacy in a concentration-dependent manner. In vitro stability assessments reveal that the aptamers remain stable in plasma and whole blood for up to 24 h. This finding is crucial for their potential application in clinical settings. Importantly, the thrombin inhibitory activity of the aptamers can be reversed by employing reverse complement sequences, providing a mechanism to counteract their anticoagulant effects when necessary to avoid excessive bleeding. These thrombin aptamers have been determined to be safe, with no observed mutagenic or immunogenic effects. Overall, these findings highlight the promising characteristics of these newly developed thrombin DNA aptamers, emphasizing their potential for therapeutic applications in the field of anticoagulation therapy. Moreover, the inclusion of an antidote in the coagulation therapy regimen can improve patient safety, ensure greater therapeutic efficacy, and minimize risk during emergency situations.

The impact of gender differences on the clinical characteristics of critically ill patients with venous thromboembolism: A retrospective, observational study

“…Reduced APTT is associated with increased risk of VTE occurrence, [ 26 , 27 ] the data of this study also shows that the PT ( P = .041), APTT ( P = .040) is significantly higher than that of female patients, indicating that the coagulation levels of these male patients are significantly higher than those of female patients, may be related to the use of anticoagulants. [ 28 , 29 ] The clinical use of D-dimer testing in anticoagulated patients is very limited, [ 30 ] but D-dimer enhances thrombus risk in cancer patients, [ 31 ] blood biochemical analysis data showed that female patients had higher but not significant D-dimer than male patients ( P = .739), and C-reactive protein was significantly less than male patients ( P = .032). Creatinine and urea level can serve as an indicator of renal function, [ 32 ] and an increase in blood urea nitrogen/creativity ratio may be related to an increased risk of VTE, [ 33 ] the data of this study showed that male patients had higher creatinine( P < .001) and urea ( P < .005) level than female patients, data from blood gas analysis showed that PaO 2 ( P = .034) and K + ( P = .010) was significantly higher in male patients than in female patients, considering the preventive effect of non-vitamin K antagonist oral anticoagulants on VTE, [ 34 , 35 ] we speculate that higher blood potassium levels in males are also one of the reasons for their higher incidence of VTE.…”