Angiopoietin-2 levels are associated with retinopathy and predict mortality in Malawian children with cerebral malaria

Objective: To investigate the relationship among the angiopoietin–Tie-2 system, retinopathy, and mortality in children with cerebral malaria.

Design: A case–control study of retinopathy-positive vs. retinopathy-negative children with clinically defined cerebral malaria.

Setting: Queen Elizabeth Central Hospital in Blantyre, Malawi.

Subjects: One hundred fifty-five children presenting with severe malaria and meeting a strict definition of clinical cerebral malaria (Blantyre Coma Score <=2, Plasmodium falciparum parasitemia, no other identifiable cause for coma) were included in the study.

Interventions: None.

Measurements and Main Results: Clinical and laboratory parameters were recorded at admission and funduscopic examinations were performed. Admission levels of angiopoietin-1, angiopoietin-2, and a soluble version of their cognate receptor were measured by enzyme-linked immunosorbent assay. We show that angiopoietin-1 levels are decreased and angiopoietin-2 and soluble Tie-2 levels are increased in children with cerebral malaria who had retinopathy compared with those who did not. Angiopoietin-2 and soluble Tie-2 were independent predictors of retinopathy (adjusted odds ratio [95% CI], angiopoietin-2, 4.3 [1.3–14.6], p = .019; soluble Tie-2, 9.7 [2.1–45.8], p = .004). Angiopoietin-2 and soluble Tie-2 were positively correlated with the number of hemorrhages, the severity or retinal whitening, and the extent of capillary whitening observed on funduscopic examination (p < .05 after adjustment for multiple comparisons). Angiopoietin-2 and soluble Tie-2 levels were elevated in children with cerebral malaria who subsequently died and angiopoetin-2 was an independent predictor of death (adjusted odds ratio: 3.9 [1.2–12.7], p = .024). When combined with clinical parameters, angiopoetin-2 improved prediction of mortality using logistic regression models and classification trees.

Conclusions: These results provide insights into mechanisms of endothelial activation in cerebral malaria and indicate that the angiopoietin–Tie-2 axis is associated with retinopathy and mortality in pediatric cerebral malaria.