Measurement of plasma sphingosine 1-phosphate

尽管1-磷酸鞘氨醇(sph-1-P)被报道参与多种细胞过程，并且这种具有生物活性的鞘磷脂的生理作用已被强烈地提出，但很少有研究揭示在生理条件下在人体样本中存在sph-1-P，包括体液和细胞。在本研究中，我们鉴定了sph-1-P是人体血浆和血清的正常成分。血浆和血清中SPH-1-P水平分别为191(Sy.+-)。[)79和484()SY+-。[)82pmol/ml(平均值(]SY+-.[SD，n=8]。此外，对6名健康成人的配对血浆和血清标本进行Sph-1-P测定，发现血清Sph-1-P/血浆Sph-1-P的比值为2.65(SY+-)。[)1.26(平均值(]正数+-[)SD)。凝血过程中释放Sph-1-P的来源很可能是血小板，因为与其他血细胞相比，血小板大量储存Sph-1-P，并在刺激时释放部分储存的Sph-1-P。我们还研究了SPH-1-P在血浆中的相关代谢。[&lt；@D13@&gt；D1H]Sph很稳定，在血浆中完全不代谢，但能迅速进入血小板，在富含血小板的血浆中主要代谢为Sph-1-P。[&lt；@D13@&gt；D1H][&lt；@d13@&gt；D1H][&lt；@d13@&gt；D1H]sph在血浆中没有变化，表明血浆中不含有降解sph-1-P所需的酶。总之，血小板可以将Sph转化为Sph-1-P，并且是后者在血液中的储存位置。鉴于Sph-1-P具有多种生物学效应，活化的血小板释放Sph-1-P可能参与多种生理和病理生理过程，包括血栓形成、止血、动脉粥样硬化和伤口愈合。

Although sphingosine 1-phosphate (Sph-1-P) is reportedly involved in diverse cellular processes and the physiological roles of this bioactive sphingolipid have been strongly suggested, few studies have revealed the presence of Sph-1-P in human samples, including body fluids and cells, under physiological conditions. In this study, we identified Sph-1-P as a normal constituent of human plasma and serum. The Sph-1-P levels in plasma and serum were 191 (]SY.+-。[) 79 and 484 (]SY.+-。[) 82 pmol/ml (mean (]SY.+-。[) SD,n=8), respectively. Furthermore, when Sph-1-P was measured in paired plasma and serum samples obtained from 6 healthy adults, the serum Sph-1-P/plasma Sph-1-P ratio was found to be 2.65 (]SY.+-。[) 1.26 (mean (]SY.+-。[) SD). It is most likely that the source of discharged Sph-1-P during blood clotting is platelets, because platelets abundantly store Sph-1-P compared with other blood cells, and release part of their stored Sph-1-P extracellularly upon stimulation. We also studied Sph-1-P-related metabolism in plasma. [<@D13@>D1H] Sph was stable and not metabolized at all in plasma, but was rapidly incorporated into platelets and metabolized mainly to Sph-1-P in platelet-rich plasma. [<@D13@>D1H] Sph was found to be unchanged in plasma, revealing that plasma does not contain the enzymes needed for Sph-1-P degradation. In summary platelets can convert Sph into Sph-1-P,and are storage sites for the latter in the blood. In view of the diverse biological effects of Sph-1-P,the release of Sph-1-P from activated platelets may be involved in a variety of physiological and pathophysiological processes, including thrombosis, hemostasis, atherosclerosis and wound healing.