Elevated Cell-Specific Microparticles Are a Biological Marker for Cerebral Dysfunctions in Human Severe Malaria

Cerebral malaria (CM) and severe anemia (SA) are the most severe complications of Plasmodium falciparum infections. Although increased release of endothelial microparticles (MP) correlates with malaria severity, the full extent of vascular cell vesiculation remains unknown. Here, we characterize the pattern of cell-specific MP in patients with severe malaria. We tested the hypothesis that systemic vascular activation contributes to CM by examining origins and levels of plasma MP in relation to clinical syndromes, disease severity and outcome. Patients recruited in Douala, Cameroon, were assigned to clinical groups following WHO criteria. MP quantitation and phenotyping were carried out using cell-specific markers by flow cytometry using antibodies recognizing cell-specific surface markers. Platelet, erythrocytic, endothelial and leukocytic MP levels were elevated in patients with cerebral dysfunctions and returned to normal by discharge. In CM patients, platelet MP were the most abundant and their levels significantly correlated with coma depth and thrombocytopenia. This study shows for the first time a widespread enhancement of vesiculation in the vascular compartment appears to be a feature of CM but not of SA. Our data underpin the role of MP as a biomarker of neurological involvement in severe malaria. Therefore, intervention to block MP production in severe malaria may provide a new therapeutic pathway

Predictors of childhood severe malaria in a densely populated area: Douala, Cameroon

The physiopathology of malaria is complex. More understanding would be useful for a better management of the disease. This study was undertaken to describe clinical presentation and some biochemical parameters in childhood malaria in order to identify some factors of disease severity. Eighty six (86) children (0 to 15 years old) were recruited in Douala, clinical data recorded and blood sample collected. Thirty one (31) healthy children were also targeted to serve as control. Blood glucose, hemoglobin, transaminases and nitric oxide were determined by spectrophotometry. C reactive protein (CRP) was also investigated. The results confirmed that severe malaria significantly affects children under 5 years. Severe malaria was associated with hyperpyrexia and prostration. Coma, convulsions and unconsciousness were more indicative of cerebral malaria. Hemoglobin and blood glucose levels decreased significantly in severe malaria patients compared with uncomplicated malaria patients or controls (P < 0.001). On the contrary, blood transaminases and CRP levels increased significantly in malaria patients compared to controls (P < 0.001). From these results, it is clear that childhood severe malaria is associated with prostration, coma, unconsciousness, convulsions and hyperpyrexia. Low levels of haemoglobin and glycemia, as well as high levels of transaminases and CRP has been identified as predictor of malaria severity.Keywords: Childhood malaria, clinical presentation, physiopatholog

Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.

Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses

Predictors of childhood severe malaria in a densely populated area: Douala, Cameroon

The physiopathology of malaria is complex. More understanding would be useful for a better management of the disease. This study was undertaken to describe clinical presentation and some biochemical parameters in childhood malaria in order to identify some factors of disease severity. Eighty six (86) children (0 to 15 years old) were recruited in Douala, clinical data recorded and blood sample collected. Thirty one (31) healthy children were also targeted to serve as control. Blood glucose, hemoglobin, transaminases and nitric oxide were determined by spectrophotometry. C reactive protein (CRP) was also investigated. The results confirmed that severe malaria significantly affects children under 5 years. Severe malaria was associated with hyperpyrexia and prostration. Coma, convulsions and unconsciousness were more indicative of cerebral malaria. Hemoglobin and blood glucose levels decreased significantly in severe malaria patients compared with uncomplicated malaria patients or controls (P < 0.001). On the contrary, blood transaminases and CRP levels increased significantly in malaria patients compared to controls (P < 0.001). From these results, it is clear that childhood severe malaria is associated with prostration, coma, unconsciousness, convulsions and hyperpyrexia. Low levels of haemoglobin and glycemia, as well as high levels of transaminases and CRP has been identified as predictor of malaria severity

Correlations between MP and some clinical/biological parameters.

<p>A to E: correlations between P-MP numbers and temperature, fever resolution time (FRT), Blantyre coma score (BCS), coma resolution time (CRT) and platelet counts, respectively. F: correlation between R-MP and hemoglobin levels (Hgb).</p

Total and cellular MP levels per µl of plasma at follow-up/discharge (7 days after admission:

<p><i>A</i>) versus levels on admission. (<b>A</b>): T-MP:annexin V⁺; (<b>B</b>): P-MP:CD41⁺; (<b>C</b>): E-MP:CD105⁺; (<b>D</b>): R-MP:CD235a⁺; (<b>E</b>): M-MP:CD11b⁺; (<b>F</b>): L-MP:CD3⁺. Dot plot representations showing how in most of the cases, MP levels decreases in patients with CM at discharge (<i>D</i>). Control group is represented to show that patient levels are returning to control levels. C: Controls; SA: severe malaria anemia patients on admission; CM: cerebral malaria patients on admission; CM+SA: patients with the combine symptoms of CM and SMA on admission; SA(D): severe malaria anemia patients at discharge; CM(D): cerebral malaria patients at discharge; CM+SA(D): patients with the combine symptoms of CM and SMA at discharge; MP levels are given in MP/µl of plasma. The values of the deceased patients are presented as black stars on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013415#pone-0013415-g003" target="_blank">Figure 3</a>. *: p<0.05, **: p<0.001, ***: p<0.0001.</p

Flow cytometry analysis details and representative cytograms in a CM patient.

<p>MP were discriminated by their size and structures (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013415#pone-0013415-g001" target="_blank">Fig. <b>1A</b></a>). And events in MP gate were further analyzed to differentiate Annexin V⁺ MP from the background signal. An internal standard, constituted of fluorosphere beads of a known size and at a known concentration was used to help set the MP gate and calculate the MP level. Representative cytograms: <b>1B</b> to <b>1H</b> Illustrations of the differences in MP positive events in cytograms representing total MP and cell-derived MP in a CM patient. (<b>B</b>): T-MP:annexin V⁺; (<b>C</b>): P-MP:CD41⁺; (<b>D</b>): E-MP:CD105⁺; (<b>E</b>): R-MP:CD235a⁺; (<b>F</b>): E-MP:CD51⁺; (<b>G</b>): M-MP:CD11b⁺; (<b>H</b>): L-MP:CD3⁺.These MP positive events were used in the calculations of the number of MP/µl of plasma (see the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013415#s2" target="_blank">methods</a> section).</p