Serotonin metabolism in patients undergoing hemodialysis

To determine the pathogenic role of serotonin (5-HT), we investigated 5-HT metabolism in undergoing hemodialysis (HD). Mean value of platelet 5-HT in patients undergoing HD was significantly lower than that of normal controls (0.22 +/- 0.16 pmol/10(5) platelets versus 0.35 +/- 0.13 pmol/10(5) platelets, p <0.02). While platelet uptake of 5-HT in normal controls reached a plateau in each experiment after incubation with authentic 5-HT for 60 min, platelet uptake of 5-HT in patients undergoing HD reached various levels. We found significantly lower platelet 5-HT levels in patients with diabetes mellitus (DM) after HD compared with those in patients with chronic glomerulonephritis (p <0.05). The pathogenic role of serotonergic amplifying mechanism especially in patients with DM should be investigated. Second, we investigated plasma 11-dehydro-thromboxane B-2 (11-DTXB(2)) levels in patients undergoing HD. Mean level of plasma 11-DTXB(2) concentration in patients after HD was significantly higher than in patients before HD (32.8 +/- 17.0 pg/ml versus 23.7 +/- 7.2 pg/ml, p <0.02). Increased plasma levels of 11-DTXB(2) after HD were regarded as an indication of hypercoagulation. Our results provide evidence that several factors such as hypercoagulation, heparin, 5-HT uptake of platelet, or causal diseases of renal failure could be responsible for the lower platelet 5-HT levels in patients undergoing HD.