Development of Antithrombotic Aptamers: From Recognizing Elements to Drugs.

Blood hemostasis is attained with two sophisticated interconnected network systems, a coagulation cascade and a platelet activation system. Multiple inhibitors were developed to various components of both systems to prevent thrombosis-related morbid events that are of extremely high frequency in the human population. Antithrombotic inhibitors possess both positive and negative aspects. One of the essential modern requirements is a controllable mode of action for both anticoagulants and antiplatelets that could be achieved due to the high affinity and specificity of the inhibitor, as well as a possibility to apply an antidote, which quickly annihilates activity of the inhibitor and restores the proper hemostasis. Aptamers are DNA or RNA oligonucleotides with particular tertiary structure, such as DNA guanine quadruplex. Besides antibodies and other peptides/proteins, aptamers are one more example of the molecular recognizing elements that specifically bind to the target. Therefore, aptamers could be developed into a promising novel class of the drugs with high affinity, specificity, innate low toxicity, and rational antidote. Several aptamers with prospective antithrombotic activity have been reviewed; some of them are in preclinical and clinical trials.