The effect of immunosuppressive agent FTY-720 on coagulation, nitroxidergic lung activity and water balance in experimental antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic acquired autoimmune thrombophilia that leads to impaired non-respiratory lung functions due to the circulation of antiphospholipid antibodies, shifting the balance between the coagulation link of hemostasis and the anti-coagulation system towards hypercoagulation. The research examines the modulating effect of FTY-720 on the water balance, coagulation and NO-activity of the lungs under conditions of experimental APS. The functional activity of FTY-720 is largely due to its ability to bind to S1P1 receptors and block signaling pathways mediated by the interaction of the mediator sphingosine-1-phosphate with them. The main effect of FTY-720 is immunosuppression, which develops as a result of the drug’s receptor interaction predominantly with S1P1 receptors, resulting in the retention of autoreactive lymphocytes in lymph nodes, and prevents further spread of inflammation and damage. The experiments were conducted on 85 male rats, divided into groups as follows: The first group of animals (n = 30) was injected with cardiolipin antigen every other day for three weeks for APS modeling; the rats of the second group (n = 25), which served as a control group, were similarly injected with 0.9% NaCl; APS modeling and FTY-720 injection were combined on the remaining animals (n = 30). Three weeks later, arterial (art) and venous (ven) blood was taken, in which APTT and PT were determined using a hemocoagulometer CGL 2110 “Solar” and the corresponding coefficients of APPT of ven/art, PT of ven/ art were calculated. NO-activity was assessed by the content of plasma NO and NO bronchoalveolar lavage obtained by washing the extraction of the bronchopulmonary complex in anesthetized animals. To study the water balance of the lungs, the mass of moist and dried lungs was measured, were determined the total, extra- and intravascular fluid of the lungs. In APS, an increase in APTT and PT of arterial and venous blood was observed, an increase in the level of NO in bronchoalveolar lavages against the background of worsening nitroxidergic activity of the lungs – the NO index of ven/art decreased. There was a positive effect of FTY- 720 on the restoration of non-respiratory lung functions in APS.