Center for the Study of Complex Malaria in India

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PROJECT 3: SUMMARY Plasmodium falciparum malaria is a major cause of mortality and morbidity in the developing world and cerebral malaria (CM), its most severe form, accounts for the majority of malaria-associated deaths. The pathophysiology and the molecular mechanisms underlying this complex neurologic syndrome are still poorly understood. CM predominantly affects adults in lower transmission settings (Asia) and children in high- transmission settings (Africa). Clinical presentations differ between the two age groups, suggesting that pathologies may be dissimilar. Rigorous comparisons of the pathophysiology of CM between the two geographically distinct areas have, however, never been performed. Project 3 will use magnetic resonance imaging (MRI) techniques to study CM pathogenesis in the first comprehensive comparative analysis of its kind between patients in Raurkela, India and Blantyre, Malaŵi. The study will leverage the presence of MRI scanners at both sites, as well as the use of mirroring clinical protocols, which include retinal examinations, serial MRI scans, and a follow-up visit. The higher magnetic field strength of the MRI scanner in Raurkela will also allow us to assess the respective roles of cytogenic vs. vasogenic edema in CM patients with cerebral swelling. In parallel, we will carry out an exhaustive and complementary characterization of the cerebral pathologies in different categories of fatal adult CM cases, identified through ophthalmologic and MRI examinations. We will use a technique that renders full autopsies unnecessary by sampling brain tissue through the supraorbital plate of deceased patients. We will then assess the potential links between blood- brain barrier impairment, retinopathies, and brain swelling in adult CM. Findings will be compared with those recently obtained in a similarly well-defined cohort in Malaŵi, using identical techniques and read-out parameters. Lastly, we will investigate how parasite virulence factors and host molecular determinants drive CM pathophysiology in patients from India and Malaŵi. For this, we will apply advanced machine-learning models of CM disease causation in both populations, informed by clinical (neuroimaging, fundus examination, coagulation factors, etc.) and laboratory (parasite var gene transcript analysis, plasma biomarkers, etc.) investigations. As part of investigating parasite virulence factors, we will test the hypothesis that severe brain swelling and retinopathies are linked to high levels of endothelium protein C receptor (EPCR)-binding parasites with strong blockade activity for activated protein C (APC)-EPCR protective pathways. The primary outcome of this project will be a better understanding of the different pathogenetic processes involved in pediatric and adult CM, which will guide the development of new adjunct therapies.