The quality control of stroma-free hemoglobin: lysophosphatidylcholine, a component of stromal phospholipids, as candidate vasoconstrictive factor.
We characterized stromal phospholipids in stroma-free hemoglobin (SFH) by normal-phase and cation-exchange HPLCs, and found that SFH contained not only four phospholipids which were the major constituent classes in membrane, but also several peaks which were not yet identified. The residual amounts of these lipids in SFH were changed with storage of red cell concentrates. The four major phospholipids decreased concomitantly with storage, whereas the unidentified peaks increased after 21 days and then decreased after 48 days. We also found that SFH contained lysophosphatidylcholine (LPC) at 5.71 micrograms/ml, which was the deacylated metabolite of phosphatidylcholine (PC). These results suggest that stromal phospholipids are degradable. Since LPC is known to be capable of producing a defect in endothelium-dependent arterial relaxation, we next examined the effect of stromal lipids on vascular tone in rabbit thoracic aortic strips. Preincubation with the crude lipid extract or the LPC purified from SFH by TLC significantly inhibited acetylcholine (ACh)-induced relaxation in phenylephrine (PhE)-precontracted tissues. These observations have led to the proposal that LPC, a component of stromal phospholipids, induces vasoconstriction as a result of inhibition of endothelium-dependent vasorelaxation.
Matsuda
N
N
Hokkaido Red Cross Blood Center, Sapporo, Japan.
Nakai
K
K
Amano
M
M
Takahashi
T A
TA
Ohta
T
T
Sakuma
I
I
Kitabatake
A
A
Nakazato
Y
Y
Sekiguchi
S
S
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001802:Blood Substitutes / Q000737:chemistry* / Q000592:standards* / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D004340:Drug Contamination; D005260:Female; D006454:Hemoglobins / Q000737:chemistry* / Q000592:standards* / Q000633:toxicity; D006801:Humans; D066298:In Vitro Techniques; D008244:Lysophosphatidylcholines / Q000032:analysis* / Q000633:toxicity; D008297:Male; D010743:Phospholipids / Q000737:chemistry; D011786:Quality Control; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000032:analysis* / Q000633:toxicity
D001802:Blood Substitutes; D006454:Hemoglobins; D008244:Lysophosphatidylcholines; D010743:Phospholipids; D014662:Vasoconstrictor Agents; C016484:hemoglobin, stroma free