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. C17-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
Ryunosuke
R
Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan.
Nakamura
Kazuhiro
K
Okubo
Shigeo
S
Hosogaya
Shigemi
S
Ozaki
Yukio
Y
Tozuka
Minoru
M
Osima
Noriko
N
Yokota
Hiromitsu
H
Ikeda
Hitoshi
H
Yatomi
Yutaka
Y
D001774:Blood Chemical Analysis / Q000379:methods*; D004912:Erythrocytes / Q000378:metabolism*; D006262:Health; D006801:Humans; D008246:Lysophospholipids / Q000097:blood*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000097:blood
D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D013110:Sphingosine