Selective reduction of serotonin storage and ATP release in chronic renal failure patients platelets

Hemorrhagic complications, as monitored by skin bleeding times, occur in a significant number of chronic renal failure (CRF) patients. The etiology of hemostatic defects in these patients is complex and ill defined. Our studies demonstrate, for the first time, that activated platelets, derived from CRF patients, release significantly (P less than .001) less ATP than controls while the percent of releasable serotonin (5HT), assumed to be co-stored with ATP, is unaltered. Analysis of the CRF-derived platelets reflects a selective acquired storage pool defect with significantly (P less than .001) reduced 5HT levels while their dense granule contents of ATP and ADP are normal. The comparison of ATP release from platelets derived from CRF patients whose bleeding times were less than 9 min to those with bleeding times of 9 min or greater was significantly different (P less than .02). This report demonstrates for the first time that there is a statistically significant correlation of ATP release and 5HT content to bleeding times (P less than .001). The perturbation of platelet 5HT uptake, 5HT dense granule content, and ATP release appears to result from newly described altered plasma factors, detected by our in vitro mixing studies. It is proposed that the reduced level of releasable platelet 5HT and ATP contributes to bleeding disorders commonly encountered in CRF patients.