Revisiting the effect of cholesteryl sulfate on clotting and fibrinolysis: Inhibition of human thrombin and other human blood proteases
Research article published in Heliyon (2024)
Abstract
Cholesteryl sulfate (CS) was quantitatively synthesized by microwave-assisted sulfonation of cholesterol followed by sodium exchange chromatography. In vitro effects of CS on human thrombin and other serine proteases of the coagulation and fibrinolysis processes were investigated using a series of biochemical and biophysical techniques. CS was found to inhibit thrombin with an IC50 value of 140.8 ± 21.8 μM at pH 7.4 and 25 ○C. Michaelis-Menten kinetics indicated that thrombin inhibition by CS is non-competitive (allosteric) in nature. Fluorescence-based binding studies indicated that CS binds to thrombin with a KD value of 180.9 ± 18.9 μM. Given the lack of competition with heparins and a hirudin peptide in competitive inhibition assays, it appears that CS does not bind to thrombin's exosites 1 or 2 and it rather recognizes a different allosteric exosite. CS was found to partially inhibit thrombin-mediated fibrinogen activation with an IC50 value of 175.5 ± 17.5 μM and efficacy of ∼26.0 ± 6.6%. Likewise, CS selectively doubled the activated partial thromboplastin time with EC2x of 521 μM. Interestingly, CS was found to also inhibit factors Xa and XIa as well as plasmin with IC50 values of ∼85-250 μM and efficacy of 94-100%. Nevertheless, CS most potently inhibited factor XIIa with an IC50 Value of ∼17 μM and efficacy of 60%. Surprisingly, CS did not inhibit factor IXa. These results encourage further in vitro and in vivo investigation of CS to better understand its (patho-) physiological roles in coagulation and hemostasis.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Cholesteryl sulfate (CS) was quantitatively synthesized by microwave-assisted sulfonation of cholesterol followed by sodium exchange chromatography.
Por qué esto importa para la hirudoterapia
Este estudio in vitro sintetizó sulfato de colesterilo (SC) y caracterizó sus efectos inhibidores sobre la trombina humana y otras proteasas de la coagulación/fibrinólisis. El SC inhibió la trombina (IC50 ~140,8 μM) mediante unión no competitiva (alostérica), inhibió parcialmente la activación del fibrinógeno y prolongó el aPTT; también inhibió los factores Xa, XIa, XIIa y la plasmina, pero no el factor IXa. Los ensayos de inhibición competitiva no mostraron competencia con heparinas ni con un péptido de hirudina, lo que indica que el SC se une a un exositio alostérico distinto de la trombina. Para el ámbito de la ASH, la conexión es indirecta: se utiliza un péptido de hirudina como herramienta para mapear la unión al exositio-1 de la trombina, confirmando que el SC actúa en otro sitio, pero la hirudina no es el agente investigado. El estudio se refiere a un sulfato de esterol sintético, no a la terapia con sanguijuelas ni al secretoma de la sanguijuela; la relevancia se limita a proporcionar contexto mecanístico sobre la inhibición de la trombina distinta del modo de acción de la hirudina.
Citación
Revisiting the effect of cholesteryl sulfate on clotting and fibrinolysis: Inhibition of human thrombin and other human blood proteases
Al-Horani RA · Heliyon, 2024
Contexto clínico relacionado
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026