White matter (WM) abnormalities have been observed in a variety of neurological conditions, including those suffering from cerebral malaria (CM). CM is a serious complication of Plasmodium falciparum infection, and has a profoundly devastating effect especially on children, non-immune travelers and military personnel. Clinically, CM can result in several neurological problems, including impaired consciousness, seizures and reversible coma. CM is associated with a high mortality of up to 30%, with the highest rate in children. In CM survivors, such as African children and non-immune travelers, persistent neurologic deficits may occur. The hallmark of CM pathology is the intra-vascular sequestration of parasitized red blood cells (PRBC) inside high endothelial venules throughout the brain. PRBC bind to the blood brain barrier (BBB) endothelium in both white matter (WM) and gray matter (GM). Interestingly, PRBC do not invade into the brain and their sequestration in blood vessels leads to a distinctly different pathology in the brain's WM versus GM. Postmortem studies reveal a clear hemorrhagic pathology within WM. Our previous data showed highly inflammatory responses associated with GM endothelium. Yet, little is known of the factors that cause these differences of the brain endothelium residing in GM versus WM and how any potential differences could relate to divergent functional responses in CM. Therefore, we hypothesize that, due to differences in the direct physiological environment of GM and WM (e.g. astrocyte, pericyte- or oligodendrocyte), the vessel endothelium in these different brain tissues exhibit differing functional properties. These differential endothelial properties in combination with specific PRBC binding patterns (due to the expression of alternating var- genes), result in the observed diverging CM pathologies in WM versus GM. In this proposal, we intend to study the differences in functional responses of WM versus GM endothelium to PRBC, using a combination of in vitro BBB models of human brain GM and WM endothelium, and compare these differences to in situ vessels in human brain samples. We will test for selective binding of PRBC and differing host responses with respect to inflammation, barrier response and coagulation markers. For future studies, we will validate our results by analyzing vessels from CM patient samples. This application is an exploratory R21 that combines the analysis and in vitro BBB model for HUMAN CM with analysis of blood vessels derived from human WM and GM brain tissue. These studies will provide an improved understanding of the BBB and could provide new understandings of the molecular mechanisms of the brain vessels differentiation in WM versus GM that may also be implicated in other neurological diseases.
White matter (WM) abnormalities are evident in several neurological diseases, especially in cerebral malaria (CM). Little is known of the differences between GM & WM blood vessels. In this exploratory R21 we propose to study this gap in knowledge, potential leading to novel information on brain function and novel therapeutic targets.
| Noumbissi, Midrelle E; Galasso, Bianca; Stins, Monique F (2018) Brain vascular heterogeneity: implications for disease pathogenesis and design of in vitro blood-brain barrier models. Fluids Barriers CNS 15:12 |
