Molecular Mechanisms of Iron Metabolism and Overload

Iron represents an essential element required for normal physiologic processes throughout organ systems. A vast network of transporters is involved not only in uptake of this element but in processing, oxidation, and recycling to maintain it in a tight balance to avoid excess storage. This complex network of transporters, including heme and ferroportin, among many others, are responsible for facilitating inter-organ tissue iron exchange and availability, contributing to overall heme homeostasis. However, exposure to high levels of iron can overwhelm compensatory mechanisms that result in its accumulation and toxicity. This is the case of patients with genetic diseases such as hemoglobinopathies who suffer from chronic anemia and require, in most instances, a lifetime of red blood cell transfusions to overcome disease crises. Thus, in light of the extensive role of iron in the body, the aim of this review is to present important metabolic pathways involved in iron homeostasis across the cardiovascular, reproductive, hematopoietic, urinary, respiratory, endocrine, and central nervous systems while contrasting these against negative effects caused by iron excess.