Estatin B

For years the mainstay of antiphospholipid syndrome treatment has been anticoagulation and antiplatelet therapy, but the autoimmune nature of the disease, and complications of these therapies, created the need to develop new therapeutic strategies. New therapeutic alternatives inhibit at different levels, the cascade of events leading to the pro-thrombotic state characteristic of the antiphospholipid syndrome. We conducted a literature review of these new treatments, focusing on the pathophysiological bases that support them and their possible clinical applications.

New thiol protease inhibitors, estatins A and B, were isolated from the culture filtrate of Myceliophthora thermophila M4323. The basic, water-soluble inhibitors were characterized as having an agmatine, trans-epoxysuccinic acid and L-phenylalanine or L-tyrosine moieties in the structure. The molecular formulas C18H25N5O5 and C18H25N5O6 for A and B were indicated by elemental analysis and fast atom bombardment MS. Estatins were specific inhibitors against thiol proteases such as papain, ficin and bromelain. They suppressed IgE antibody production in mice, but not IgG.