Iron chelators are substances or medicines designed to remove excess iron from the body. These compounds act like a “molecular claw” or “magnet” that seeks out and binds to free iron atoms. Once bound, the iron is no longer able to cause harm, and the combined molecule can then be safely removed from the body. This process is known as chelation therapy.
The Role of Iron and Iron Overload
Iron is an essential mineral that plays a central role in numerous bodily functions, including oxygen transport and energy production. It is a component of hemoglobin, the protein in red blood cells responsible for carrying oxygen from the lungs to tissues throughout the body. While iron is necessary for life, the body has no efficient way to excrete excess iron, making it prone to accumulation.
When too much iron accumulates, a condition known as iron overload or hemochromatosis occurs. This excess iron can deposit in organs like the liver, heart, and pancreas, leading to cellular damage and serious health complications such as liver cirrhosis, heart failure, and diabetes.
Iron overload can stem from genetic conditions, such as hereditary hemochromatosis, where the body absorbs too much iron from the diet. It also commonly develops in individuals who receive frequent red blood cell transfusions, as seen in conditions like thalassemia or sickle cell disease. Each transfusion introduces additional iron, which can build up and exceed the body’s storage capacity.
How Iron Chelators Work
Iron chelators function by forming a stable complex with excess iron atoms in the body. These specialized molecules are designed with specific binding sites that strongly attract and hold onto iron ions. Once the iron is bound, it becomes chemically inert, meaning it can no longer participate in harmful reactions that generate damaging free radicals.
The newly formed iron-chelator complex is water-soluble. This property allows the complex to circulate in the bloodstream and then be filtered out by the kidneys for excretion in urine or by the liver for removal in feces. This process effectively removes accumulated iron from tissues and organs, preventing or reducing further iron-mediated damage. Different chelators target iron in various cellular compartments, such as non-transferrin bound iron or iron within ferritin.
Types of Prescription Iron Chelators
Prescription iron chelators are the primary medical treatment for systemic iron overload, differing in administration and mechanisms. Deferoxamine, also known as Desferal, has been a standard treatment for many years.
Deferoxamine is not absorbed orally, so it must be administered parenterally, through slow subcutaneous or intravenous infusion. Patients often use a portable pump for 8 to 12 hours daily, which can be a significant time commitment. This chelator primarily binds to non-transferrin bound iron and iron found in ferritin, with the resulting complex excreted via the kidneys and bile.
Deferasirox, also known as Exjade and Jadenu, represents a newer oral option for iron chelation therapy. It is an oral chelator taken once daily as a dispersible or film-coated tablet. This medication scavenges labile plasma iron, the form responsible for tissue damage, and its complexes are primarily excreted in the stool.
Deferiprone, also known as Ferriprox, is another oral iron chelator, often taken multiple times daily, though some newer formulations allow twice-daily dosing. It is particularly noted for its efficiency in reducing cardiac iron overload. Deferiprone chelates cytosolic labile iron, with its complexes mainly excreted through urine. The choice among these chelators depends on the patient’s condition, severity of iron accumulation, and individual tolerance.
Natural Compounds with Chelating Properties
Certain natural compounds can bind to iron, a characteristic known as chelation. These are found in various foods and plants. Examples include polyphenols and tannins, abundant in beverages like tea and coffee. Phytic acid, another natural chelator, is present in grains, legumes, and nuts.
These compounds primarily affect the absorption of dietary iron from the gut, reducing the amount the body takes in from food. For instance, they form complexes with iron in the digestive tract, making it less available for absorption into the bloodstream. However, their chelating effect is significantly weaker than prescription medications used in chelation therapy. They are not effective treatments for systemic iron overload, where iron has already accumulated in organs and tissues. Their role is limited to influencing dietary iron uptake and they cannot remove stored iron.