Iron deficiency may induce heart failure

Iron deficiency is one of the most prevalent nutritional deficiencies in the world, affecting an estimated two billion people, according to the World Health Organization. It is commonly associated with anaemia, but new research in mice suggests that iron deficiency in the heart can lead to heart failure, even in patients who are not anaemic and have otherwise normal levels of iron in their body. 

Research by Dr Samira Lakhal-Littleton and her team at the University of Oxford has shown that iron deficiency in the cells of specific organs is enough to affect the function of those organs, even if the patient is not anaemic and has normal iron levels in other tissues. Lakhal-Littleton’s new research shows that iron deficiency in the cells of the heart and the arteries which carry blood from the heart to the lungs, known as the “pulmonary arteries”, can lead to cardiovascular dysfunction.

The pulmonary arteries carry blood from the right ventricle of the heart to the lungs for oxygenation. Lakhal-Littleton’s new research shows that iron deficiency in the cells of the pulmonary arteries induces “pulmonary arterial hypertension” in mice. The pulmonary arteries of patients with this condition are constricted and the pressure in them is increased as a consequence. This in turn increases the pressure of the right side of the heart, and according to Lakhal-Littleton "over time this can lead to right heart failure and heart disease."

The team were able to genetically modify mice in order to isolate iron deficiency to within the heart and the pulmonary arteries, such that the mice were otherwise healthy and, crucially, did not have anaemia. The only thing wrong with the mice was that the cells of the heart and the pulmonary arteries were unable to retain iron within the cells, and so the cells became iron deficient over time. They were surprised to find that the mice went on to develop heart failure and cardiovascular dysfunction. The team then went on to confirm many of their findings in human studies.

At the moment patients with pulmonary arterial hypertension are given drugs which try to reduce the constriction within the blood vessels of the lungs. Lakhal-Littleton thinks that this new research could change the way in which the patients are treated: “a consensus ... is gathering that maybe giving these patients iron could be beneficial”.