Plasma sphingosine-1-phosphate measurement in healthy subjects: close correlation with red blood cel
June 29th, 2008 | by admin |Plasma sphingosine-1-phosphate measurement in healthy subjects: close correlation with red blood cell parameters.
BACKGROUND: Since sphingosine-1-phosphate (Sph-1-P) plays an important role as an extracellular mediator through interaction with specific cell surface receptors, especially in the area of vascular biology and immunology/haematology, determination of its plasma concentration may become important from the clinical viewpoint. Thus, we attempted to develop a method of measuring the plasma Sph-1-P concentration for use in the clinical laboratory setting. METHODS: After two-step lipid extraction, Sph-1-P was coupled with o-phthaldialdehyde, and the resultant fluorescent derivative was separated by high-performance liquid chromatography. C(17)-Sph-1-P was used as the internal standard, instead of dihydrosphingosine-1-phosphate, which had been used previously for the same purpose but was actually detected in plasma. RESULTS: Our procedures for preparing the plasma samples and assay Sph-1-P were found to be satisfactory for clinical laboratory testing. The plasma Sph-1-P concentrations were significantly higher in men (413.1 +/- 52.0 nmol/L; mean +/- SD) than in women (352.4 +/- 39.7 nmol/L). Unexpectedly, strong positive correlations were found between the plasma Sph-1-P concentration and red blood cell (RBC)-related parameters, rather than platelet-related parameters. CONCLUSIONS: Our present study confirmed the possibility of the clinical introduction of plasma Sph-1-P measurement, and in addition, suggested that RBCs may be involved in the regulation of plasma Sph-1-P concentrations.
Ohkawa R, Nakamura K, Okubo S, Hosogaya S, Ozaki Y, Tozuka M, Osima N, Yokota H, Ikeda H, Yatomi Y.
Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan.