Anti-thrombotic Therapies: Targeting Novel Approaches to Improve the Treatment of Cardiovascular Disease

Abstract

Cardiovascular disease is the leading cause of death globally. Platelets are a well-established target in the treatment of thrombosis; however, current therapies continue to target a core group of proteins in the platelet, and many patients remain at risk for cardiovascular events. As a result, the development of novel anti-thrombotic therapeutics remains an important goal in the cardiovascular field. This dissertation focuses on three novel anti-thrombotic mechanisms and their potential as therapeutic agents. CS585, a novel prostacyclin receptor (IP) agonist, targets a well-known inhibitory pathway in the platelet that has had limited success with pharmacological intervention in the past. Sotagliflozin, a sodium-glucose cotransporter (SGLT)1/2 inhibitor developed to treat diabetes, has been observed to decrease cardiovascular risk and demonstrates an inhibitory effect on platelet activity. CS014, a novel histone deacetylase (HDAC) inhibitor, reduces thrombus formation in vivo. The work outlined in this dissertation sought to assess the viability of the three compounds as potential anti-thrombotic therapeutics. We evaluated the effects of CS585, sotagliflozin, and CS014 on platelet activation and thrombus formation in numerous in vivo and ex vivo models of thrombosis. Additionally, each compound was evaluated for a potential impact on hemostasis, a key limitation of many anti-thrombotic medications.

CS585 was developed as an analogue of the omega-6 polyunsaturated fatty acid (PUFA) metabolite 12(S)-HETrE. PUFAs have long been considered to have a cardiovascular protective effect. We conducted a clinical trial in which post-menopausal women were supplemented with PUFAs and assessed changes in their platelet activity, confirming an anti-platelet effect of PUFAs. Subsequent work in the lab determined that 12(S)-HETrE exhibited anti-platelet activity through activation of the IP receptor. Previous attempts to develop an IP analogue had limited efficacy in the blood due to low selectivity and stability; as a 12(S)-HETrE analogue, CS585 demonstrated higher selectivity and stability compared to existing IP receptor agonists, with no impact in hemostatic assessments.

In the SCORED clinical trial conducted in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD), sotagliflozin demonstrated a reduction in both myocardial infarction (MI) and stroke. We established the presence of SGLT1 and 2 in the platelet and demonstrated that sotagliflozin decreases platelet activation and thrombus formation. To determine whether this property is unique to sotagliflozin or if specific SGLT2 inhibitors exhibit similar inhibition, we compared sotagliflozin to empagliflozin, a highly selective SGLT2 inhibitor. Empagliflozin did not inhibit platelet activation or thrombus formation, while sotagliflozin demonstrated distinguishable anti-thrombotic potential with no effect on coagulation or bleeding.

CS014 was developed as a valproic acid (VPA) analogue with the intention of decreasing the hepatotoxic effects associated with VPA. VPA has previously demonstrated the ability to decrease the risk of stroke, but its use is limited due to the risk of hepatotoxicity. We demonstrated that CS014 does not result in the production of the metabolites associated with VPA toxicity. Additionally, while CS014 did not exhibit any direct anti-platelet effects, when mice were dosed with CS014, we observed an apparent anti-thrombotic effect. CS014 also had no impact on coagulation or bleeding.

CS585, sotagliflozin and CS014 demonstrate the ability to decrease thrombus formation in vivo, albeit through three distinctly different mechanisms. The work presented in this dissertation demonstrates the anti-thrombotic effects of each compound and highlights their potential to reduce the risk of a cardiovascular event in patients at high risk.