Procoagulant Effects of Isothiazolinone Biocides, Benzisothiazolinone and Octylisothiazolinone in Platelets

Isothiazolinones are commonly used biocides that are extensively used in industrial areas and household products. The extensive usage of isothiazolinones raises concerns regarding their adverse human health effects. Isothiazolinones are readily absorbed and enter circulation. However, the potential systemic effects of isothiazolinones on the circulatory system remain unclear. Here, we examined whether the isothiazolinones, benzisothiazolinone (BIT) and octylisothiazolinone (OIT) affected platelets. In isolated platelets, BIT and OIT depleted intracellular glutathione, which led to mitochondrial reactive oxygen species (ROS) accumulation. Excessive mitochondrial ROS led to mitochondrial dysfunction, altering intracellular calcium and adenosine triphosphate homeostasis. These intracellular events activated phospholipid scramblase, externalizing phosphatidylserine, thereby enhancing procoagulant activity, as evidenced by thrombin generation. Overall, OIT showed a more potent effect than BIT. Notably, supplementation with N-acetyl-L-cysteine mitigated BIT- and OIT-induced effects, suggesting a thiol-dependent mechanism. Taken together, BIT and OIT stimulated the platelet-mediated coagulation pathway, which may increase prothrombotic risk and contribute to cardiovascular disease. These results could improve our understanding of the systemic adverse effects after isothiazolinone exposure.