Possible role of PGD_2 in malaria infections

Objective:To preliminarily investigate the possible role of prostaglandin D_2(PGD_2) in malaria infections.Methods:Blood and urinary samples(n=120 each) were collected from Thai patients with Plasmodium falciparum(P.falciparum) with moderate(n=26) and high(n=4) parasitemia,patients with Plasmodium vivax(P.vivax)(n=30),patients with fever associated with other infections(n=30),and healthy subjects(n=30).PGD_2 concentrations in plasma and urinary samples of healthy subjects,patients with fever associated with other infections and patients with malaria were determined using Prostaglandin D2-MOX express EIA kit(Cayman Chemical,USA).Results:The possible association between PGD_2 and malaria infections is clearly demonstrated with PGD_2 concentration in urine.The urinary PGD_2 concentrations were relatively high(about 5-fold) in patients with P.falciparum with moderate parasitemia and P.vivax infections compared with other groups.Furthermore,the concentration in patients with P.falciparum with moderate parasitemia and P.vivax infection were significantly higher than that in healthy subjects and patients with fever associated with other infections.Conclusions:Urinary PGD_2 concentrations may offer a more dependable and useful tool for predicting malaria severity.Confirmation is this preliminary finding is required with a larger sample size.

The role of heme-oxygenase-1 in pathogenesis of cerebral malaria in the co-culture model of human brain microvascular endothelial cell and ITG Plasmodium falciparum-infected red blood cells

Objective: To investigate the role of human host heme-oxygenase-1(HO-1) in pathogenesis of cerebral malaria in the in vitro model,Methods: The effect of human host HO-1 [human brain microvascular endothelial cell(HBMEC)] on hemoglobin degradation in the co-culture model of HBMEC and ITG Plasmodium falciparum-infected red cells(i RBC) through measurement of the enzymatic products iron and bilirubin,Results: Following exposure to the HO-1 inducer Co PPIX at all concentrations,the HBMEC cells apoptosis occurred,which could be prominently observed at 15 μM of 3 h exposure,In contrast,there was no significant change in the morphology in the non-exposed i RBC at all concentrations and exposure time,This observation was in agreement with the levels of the enzymatic degradation products iron and bilirubin,of which the highest levels(106.03 and 1 753.54% of baseline level,respectively) were observed at 15 μM vs,20 μM at 3 h vs,24 h exposure,For the effect of the HO-1 inhibitor Zn PPIX,HBMEC cell morphology was mostly unchanged,but significant inhibitory effect on cell apoptosis was seen at 10 μM for the exposure period of 3 h(37.17% of baseline level),The degree of the inhibitory effect as reflected by the level of iron produced was not clearly observed(highest effect at 10 μM and 3 h exposure),Conclusions: Results provide at least in part,insight into the contribution of HO-1 on CM pathogenesis and need to be confirmed in animal model.