Oxidative stress in malaria; implications for prevention and therapy

Abstract

Malaria affects world-wide more than 200 million people, of which 1-2 million die every year. New drugs and treatment strategies are needed to face the rapidly increasing problems of drug resistance. During a malaria infection, both host and parasite are under oxidative stress. Increased production levels of reactive oxygen species (ROS, e.g superoxide anion and the hydroxyl radical) are produced by activated neutrophils in the host and during degradation of haemoglobin in the parasite. The effects of ROS in malaria can be both beneficial and pathological, depending on the amount and place of production. Enhanced ROS production after the administration of pro-oxidants, which is directed against the intra-erythrocytic parasite, inhibits the infection both in vitro and in vivo. However, ROS are also involved in pathological changes in host tissue like damage of the vascular endothelial lining during a malaria infection (cerebral malaria). Pro-oxidants support the host defense against the parasite when working in or near the infected cell but potentially cause vascular damage when working on or near the vascular lining. Examples of pro-oxidants are found among xenobiotics and food components. Important new drugs belonging to the class of pro-oxidants are artemisinin and its derivatives. Anti-oxidants potentially counteract these agents. Treatment with anti-oxidants or chelators of metals to prevent their catalytic function in the generation of ROS may prevent vascular pathology. In addition, the iron chelator desferrioxamine, exhibits an antiparasitic activity, because iron is also essential for the proliferation of the parasite. Cytokines play an important role in ROS-related pathology of malaria, though their mechanism of action is not completely elucidated. This field might bring up new treatment concepts and drugs. Drugs which prevent host pathology, such as the cerebral complications might be life saving.

Plasmodium bergheiResists Killing by Reactive Oxygen Species

“…Because (i) macrophages during malaria produce high levels of NO and superoxide (11,18,19,26,28), which react to form peroxynitrite (4), and (ii) superoxide and peroxynitrite reportedly kill the P. falciparum parasite in vitro (16), SIN-1 treatment was used to determine whether superoxide, nitric oxide, and peroxynitrite collectively have an effect on parasite viability. Parasitized RBCs were treated with 1 mM SIN-1 for 1 h in room air and at room temperature and then injected into mice.…”

Evaluation of oxidative stress and antioxidant status of pregnant women suffering from malaria in Cameroon

“…The decrease of plasma total antioxidant capacity in malaria patients compared to the controls is in agreement with the brief "momentous" increase in oxidative stress. Due to their synergistic functioning, the non enzymatic antioxidants depresses in concert with the brief "momentous" increase in total lipid peroxides (35). Then, the antioxidants degraded by malarial parasites to derive amino acids and other vital molecules, can not be replenished by red blood cells due to lack of protein synthesis which might be one of the reasons behind overall decrease of the body antioxidant compounds (36).…”

The Antimalaria Agent Artemisinin Exerts Antiangiogenic Effects in Mouse Embryonic Stem Cell-Derived Embryoid Bodies

“…However, it has been recently suggested that ROS are also involved in pathologic changes in host tissue-like damage of the vascular endothelial lining during a malaria infection (cerebral malaria). Pro-oxidants support the host defense against the parasite when working in or near the infected cell but potentially cause vascular damage when working on or near the vascular lining (Postma et al, 1996).…”