Platelet-activating factor and lipid metabolism in acute malaria.
Platelet-activating factor (PAF) contributes to a range of pathophysiological responses in severe illness. To examine PAF metabolism in acute malaria, venous blood was drawn from 10 untreated adults with falciparum malaria, from 8 with untreated vivax malaria, and from 10 controls. Plasma lyso-PAF, produced from PAF through the enzyme acetylhydrolase (AH), was bioassayed, after acetylation to PAF, by platelet [14C]-serotonin release. AH activity was measured by hydrolysis of [3H]-acetyl-PAF. Amounts of plasma lyso-PAF were lower in falciparum (median [range] 24 [9-221] ng/ml) and vivax (35 [7-236] ng/ml) infected patients than in controls (399 [212-504] ng/ml; P < 0.01), and correlated significantly with serum total and HDL-cholesterol (P < 0.001). Plasma AH activities were similar in the control, falciparum and vivax malaria groups. These data suggest that in malaria plasma lyso-PAF values fall together with other blood lipids, but independently of changes in AH activity. This may reflect a generalised decrease in lipid and phospholipid synthesis. However, the reduction of plasma lyso-PAF concentrations in our patients was much greater than that of serum lipoproteins. This is consistent with conversion of lyso-PAF to PAF or with increased PAF-receptor interactions. These two possibilities would have pathophysiological implications.
Davis
T M
TM
University of Western Australia, Department of Medicine, Fremantle Hospital.
Sturm
M
M
Zhang
Y R
YR
Spencer
J L
JL
Graham
R M
RM
Li
G Q
GQ
Taylor
R R
RR
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D002648:Child; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D016778:Malaria, Falciparum / Q000097:blood*; D016780:Malaria, Vivax / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010972:Platelet Activating Factor / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D008055:Lipids; D010972:Platelet Activating Factor; D014280:Triglycerides; D002784:Cholesterol