Changes in platelet calcium concentration by thromboxane A2 stimulation in patients with nephrotic syndrome of...

In order to examine the intracellular thromboxane A2 (TXA2) signal transduction system in platelets of patients with nephrotic syndrome, we measured the levels of TXA2 metabolites in urine and blood and platelet calcium ion level as a result of STA2, an analog of STA2 (9,11-dimethylmethano-11,12-methano-TXA2) stimulation, and obtained the following results: (1) In pediatric patients with nephrotic syndrome, urinary thromboxane B2 (TXB2) and 11-dehydro-TXB2 excretion were signficantly higher in the onset and relapse groups compared to the remission and control groups. (2) The blood 11-dehydro-TXB2 level in the onset group was significantly higher than those in the remission and control groups. (3) Platelet calcium concentrations due to STA2 stimulation were significantly increased in the onset, relapse and remission groups compared to the control group. These findings suggest activation of the TXA2 signal transduction system in platelets of pediatric patients with nephrotic syndrome.