A role for hepcidin in the anemia caused by Trypanosoma brucei infection

Trypanosomiasis is a parasitic disease, affecting both humans and animals, in the form of Human African Trypanosomiasis and Nagana disease, respectively. Anemia is one of the most common symptoms of trypanosomiasis, and if left unchecked, can cause severe complications and even death. Several factors have been associated with the development of this anemia, including dysregulation of iron homeostasis, but little is known about the molecular mechanisms involved. Here, using murine models, we study the involvement of hepcidin, the key regulator of iron metabolism and an important player in the development of anemia of inflammation. Our data shows two stages for the progression of anemia, to which hepcidin contributes: a first stage, when anemia develops, with a likely cytokine-mediated stimulation of hepcidin and subsequent limitation in iron availability and erythropoiesis, and a second stage, of recovery, where hepcidin elevation declines due to the decreased inflammatory signal and increased production of erythroid regulators by the kidney, spleen and bone marrow, thus leading to an increase in iron release and availability and enhanced erythropoiesis. In agreement, in hepcidin knockout mice, anaemia is much milder and its recovery is complete, in contrast to wild-type animals which do not fully recover from anaemia after 21 days. Aside from all other factors known to be involved in the development of anemia during trypanosomiasis, there clearly is an important contribution of hepcidin for both its development and recovery.