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Background. Molecular mechanisms involved in the pathogenesis of severe Plasmodium falciparum malaria—specifically, cerebral malaria—are still unclear. Transforming growth factor b (TGF-b) family members are important regulators of inflammation that influence malaria pathogenesis. The soluble form of the auxiliary receptor endoglin (sEng) may play a role in malaria pathogenesis. Methods. Serum levels of sEng were measured using enzyme-linked immunosorbent-assay in Gabonese children with cerebral malaria (n = 7), severe malaria (n = 43), or uncomplicated malaria (n = 43) and were compared with levels in healthy control subjects (n = 25) and in another infectious disease group (n = 8). Results. Serum sEng levels were higher in patients with cerebral malaria and all patients with severe malaria when compared with levels in patients in the other infection group and the healthy control group. Furthermore, sEng correlated significantly with disease severity. Only 7% of patients with uncomplicated malaria and none of the control patients (patients in the other infection group or the healthy control group) had serum levels higher than 12 ng/mL, whereas this was found in 85.7% of patients with cerebral malaria and 46.5% of patients with severe malaria. Conclusions. High sEng levels may attenuate anti-inflammatory response resulting in clinical deterioration of patients with P. falciparum malaria. Our results further corroborate the role of the vascular compartment, especially the endothelium, in severe malaria pathogenesis. [ABSTRACT FROM AUTHOR]

Background: Molecular mechanisms involved in the pathogenesis of severe Plasmodium falciparum malaria (SM), are not yet fully understood. Both endothelin-1 (ET-1) and C-type natriuretic peptide (CNP) are produced by vascular endothelium and act locally as paracrine regulators of vascular tone, ET-1 being a potent vasoconstrictor and CNP having strong vasorelaxant properties., Methods: Plasma levels of ET-1 and N-terminal fragments of CNP (NT-proCNP) were studied on admission and after 24 hours of treatment, using enzyme-linked-immunosorbent-assay (ELISA) technique, in Gabonese children with severe falciparum malaria (SM, n = 50), with uncomplicated malaria (UM, n = 39) and healthy controls (HC, n = 25)., Results: Compared to HC, malaria patients had significantly higher plasma levels of ET-1 and significantly lower levels of NT-proCNP (p < 0.001 and p < 0.024 respectively). Plasma levels of NT-proCNP were additionally decreased in SM patients compared to HC (p = 0.034), whereas UM was not significantly different to HC. In the SM group we found a trend towards lower ET-1 levels compared to UM (p = 0.085)., Conclusion: In the present study, an imbalance between the vasoconstricitve and vasorelaxant endothelium-derived substances ET-1 and CNP in the plasma of children with falciparum malaria is demonstrated, presumably in favor of vasoconstrictive and pro-inflammatory effects. These results may indicate involvement of ET-1 and CNP in malaria pathogenesis. Furthermore, results of lower ET-1 and CNP levels in SM may reflect endothelial cell damage.

Background: Molecular mechanisms involved in the pathogenesis of severe malaria caused by Plasmodium falciparum are not fully understood. Matrix metalloproteinases (MMPs) are enzymes that proteolytically degrade both the extracellular matrix and nonmatrix substances with various functions in the modulation of immune response. The key inhibitors of MMPs are the tissue inhibitors of metalloproteinases (TIMPs)., Methods: We studied levels of MMP-8, MMP-9, TIMP-1, and TIMP-2 on admission and after 24 h, using an enzyme-linked immunosorbent assay, in serum specimens from 50 Gabonese children with severe malaria, 43 children with uncomplicated malaria, and 27 healthy control children., Results: Serum MMP-8 and TIMP-1 levels were significantly higher in the severe malaria and uncomplicated malaria groups, compared with those in the control group (P < .001). TIMP-1 levels were significantly higher in patients with severe malaria, compared with those in patients with uncomplicated malaria (P < .001). High TIMP-1 levels were significantly correlated with malaria severity, as determined by the simplified multiorgan dysfunction score (Spearman rank-correlation coefficient, 0.55; P < .001)., Conclusions: TIMP-1 is associated with signs and symptoms of severe malaria. MMP-8 levels are elevated in patients with severe or uncomplicated P. falciparum malaria. MMPs and TIMPs may be relevant in the pathogenesis of severe malaria, either as proteolytic enzymes that degrade the extracellular matrix or as effectors and regulators of the immune response.