Iron chelators as anti-infectives; malaria as a paradigm

Malaria is the major life threatening parasitic disease and the cause of a global public health problem. The failure of vector eradication programs and the appearance and spread of drug resistant parasites have posed the urgent challenge of developing effective, safe and affordable anti-malarial drugs. The design of such drugs is largely based on the targeting of agents to the parasite-based machinery for host digestion and to the products of hemoglobin catabolism. Iron chelators, by depriving intracellular parasites from essential iron, lead to selective suppression of parasite growth. However, by acting on parasite-impaired macrophages, chelators can also expedite resumption of phagocytosis and elimination of parasites. In order to be clinically effective, chelators need to be maintained in the blood for extensive time periods. Therapeutic doses can be attained with appropriate drug combinations and formulations or delivery devices and these must be presented in a form well tolerated by the host. The early documentation that chelation therapy has activity against human malaria has paved the road for the design of novel and more efficient remedies based on short-term iron deprivation.