Oral Activated Charcoal Prevents Experimental Cerebral Malaria in Mice and in a Randomized Controlled Clinical Trial in Man Did Not Interfere with the Pharmacokinetics of Parenteral Artesunate

Background: Safe, cheap and effective adjunct therapies preventing the development of, or reducing the mortality from, severe malaria could have considerable and rapid public health impact. Oral activated charcoal (oAC) is a safe and well tolerated treatment for acute poisoning, more recently shown to have significant immunomodulatory effects in man. In preparation for possible efficacy trials in human malaria, we sought to determine whether oAC would i) reduce mortality due to experimental cerebral malaria (ECM) in mice, ii) modulate immune and inflammatory responses associated with ECM, and iii) affect the pharmacokinetics of parenteral artesunate in human volunteers.Methods/Principal Findings: We found that oAC provided significant protection against P. berghei ANKA-induced ECM, increasing overall survival time compared to untreated mice (p<0.0001; hazard ratio 16.4; 95% CI 6.73 to 40.1). Protection from ECM by oAC was associated with reduced numbers of splenic TNF+ CD4(+) T cells and multifunctional IFN gamma(+) TNF+ CD4(+) and CD8(+) T cells. Furthermore, we identified a whole blood gene expression signature (68 genes) associated with protection from ECM. To evaluate whether oAC might affect current best available anti-malarial treatment, we conducted a randomized controlled open label trial in 52 human volunteers (ISRCTN NR. 64793756), administering artesunate ( AS) in the presence or absence of oAC. We demonstrated that co-administration of oAC was safe and well-tolerated. In the 26 subjects further analyzed, we found no interference with the pharmacokinetics of parenteral AS or its pharmacologically active metabolite dihydroartemisinin.Conclusions/Significance: oAC protects against ECM in mice, and does not interfere with the pharmacokinetics of parenteral artesunate. If future studies succeed in establishing the efficacy of oAC in human malaria, then the characteristics of being inexpensive, well-tolerated at high doses and requiring no sophisticated storage would make oAC a relevant candidate for adjunct therapy to reduce mortality from severe malaria, or for immediate treatment of suspected severe malaria in a rural setting

TNFα-induced macrophage chemokine secretion is more dependent on NF-κB expression than lipopolysaccharides-induced macrophage chemokine secretion

The transcription factor NF-κB is a pivotal intracellular regulator of many inflammatory responses and it has been proposed that it represents a potential therapeutic target. As chemokines are important for the progress of an inflammatory response by the recruitment of immuno-competent cells, the role NF-κB plays in TNFα- or lipopolysaccharides (LPS)-induced chemokine secretion by human monocyte-derived macrophages was examined. Secretion of the CXC chemokines IL-8, GROα and ENA-78, induced by TNFα, was significantly suppressed by inhibiting NF-κB, using overexpression of IκBα. However, when induced by LPS the expression of these chemokines was unaffected. In contrast, expression of the CC chemokines MIP-1α, MCP-1 and RANTES induced by TNFα or LPS was significantly inhibited by the overexpression of IκBα. Therefore, there appear to be different mechanisms regulating CC and CXC chemokine secretion by macrophages, depending on the stimulus and that TNFα and LPS can use different signaling mechanisms in macrophages to regulate chemokine synthesis

NF-κB-inducing kinase is dispensable for activation of NF-κB in inflammatory settings but essential for lymphotoxin β receptor activation of NF-κB in primary human fibroblasts

The transcription factor NF-κB is of major importance in the biology of pro-inflammatory cytokines, such as TNF-α and IL-1α, and thereby is intimately involved in the process of inflammation. Understanding the mechanisms by which NF-κB is activated in response to inflammatory stimuli has become a major goal of inflammation research. The discovery of NF-κB-inducing kinase (NIK) as a TNFR-associated factor-interacting enzyme and a potential activator of the IκBα-kinase complex appeared to have identified an important element of the NF-κB activition pathway, a view that was supported by several subsequent studies. However, recent experiments in the alymphoplasia (aly/aly) mouse, which has missense point mutation (G885R) in NIK, has challenged that view. The reasons for the discrepancy between the different studies is unclear and could be due to multiple factors, such as cell type, species of cell, or primary vs transformed cell lines. One system that has not been investigated is primary human cells. Using an adenoviral vector encoding kinase-deficient NIK, we have investigated the role of NIK in LPS, IL-1, TNF-α, and lymphotoxin (LT) βR signaling in primary human cells and TNF-α expression from rheumatoid tissue. These data show that, in the primary systems tested, NIK has a restricted role in LTβR signaling and is not required by the other stimuli tested. Also, there is no apparent role for NIK in the process of TNF-α production in human rheumatoid arthritis. These data also highlight the potential problems in extrapolating the function of signaling pathways between primary and transfected cell lines

NF-κB-inducing kinase is dispensable for activation of NF-κB in inflammatory settings but essential for lymphotoxin β receptor activation of NF-κB in primary human fibroblasts

The transcription factor NF-κB is of major importance in the biology of pro-inflammatory cytokines, such as TNF-α and IL-1α, and thereby is intimately involved in the process of inflammation. Understanding the mechanisms by which NF-κB is activated in response to inflammatory stimuli has become a major goal of inflammation research. The discovery of NF-κB-inducing kinase (NIK) as a TNFR-associated factor-interacting enzyme and a potential activator of the IκBα-kinase complex appeared to have identified an important element of the NF-κB activition pathway, a view that was supported by several subsequent studies. However, recent experiments in the alymphoplasia (aly/aly) mouse, which has missense point mutation (G885R) in NIK, has challenged that view. The reasons for the discrepancy between the different studies is unclear and could be due to multiple factors, such as cell type, species of cell, or primary vs transformed cell lines. One system that has not been investigated is primary human cells. Using an adenoviral vector encoding kinase-deficient NIK, we have investigated the role of NIK in LPS, IL-1, TNF-α, and lymphotoxin (LT) βR signaling in primary human cells and TNF-α expression from rheumatoid tissue. These data show that, in the primary systems tested, NIK has a restricted role in LTβR signaling and is not required by the other stimuli tested. Also, there is no apparent role for NIK in the process of TNF-α production in human rheumatoid arthritis. These data also highlight the potential problems in extrapolating the function of signaling pathways between primary and transfected cell lines