Ferritin

File:Ferritin 3foldchannel.png

Ferritin 3foldchannel

Ferritin is a protein that stores iron and releases it in a controlled fashion. Hence, the body has a way to sequester iron, both for protection against excess iron, which can be harmful, and to make it available when needed. Ferritin is found in most tissues as a cytosolic protein, but small amounts are secreted into the serum where it functions as an iron carrier. Serum ferritin levels are a reflection of the total amount of iron stored in the body, making it a crucial marker in the diagnosis of iron-related disorders.

Structure

Ferritin is a hollow, globular protein composed of 24 subunits. These subunits are of two types: light (L) and heavy (H) chains, which vary among different organisms and tissues, affecting the protein's iron uptake and release characteristics. The structure allows for the storage of up to 4500 iron atoms in a ferric form, within its central cavity, making it an efficient iron storage molecule.

Function

The primary function of ferritin is to store iron in a soluble, non-toxic form, and to release it in a controlled fashion. The protein plays a critical role in iron homeostasis, ensuring that iron is available for processes such as hemoglobin synthesis, while also preventing damage from iron-induced oxidative stress. Ferritin that is located in the cell cytoplasm stores iron for intracellular use, whereas serum ferritin functions to transport iron to various tissues.

Clinical Significance

1. 1. 1. Iron Deficiency and Anemia

Low serum ferritin levels are indicative of iron deficiency, which can lead to anemia. This condition is characterized by a reduced number of red blood cells or a decreased amount of hemoglobin in the blood, leading to fatigue, weakness, and shortness of breath among other symptoms.

1. 1. 1. Iron Overload

Conversely, high levels of ferritin can indicate iron overload, which can be hereditary, as in hemochromatosis, or acquired, through conditions such as chronic hemolytic anemia or excessive dietary iron intake. Iron overload can lead to damage to organs including the liver, heart, and pancreas.

1. 1. 1. Inflammation

Ferritin levels can also be elevated in the context of inflammation, infection, or chronic disease, as it is an acute-phase reactant. Thus, elevated ferritin levels must be interpreted in conjunction with other clinical findings and laboratory tests.

Diagnostic Use

Measurement of serum ferritin is a common and cost-effective laboratory test used to assess iron stores in the body. It is often used in conjunction with other tests, such as the complete blood count (CBC) and serum iron and total iron-binding capacity (TIBC) tests, to diagnose iron deficiency or overload.

Treatment

Treatment for abnormalities in ferritin levels depends on the underlying cause. Iron deficiency may be treated with iron supplements or dietary changes, while iron overload might require phlebotomy (blood removal) or chelation therapy, which involves the use of agents to remove excess iron from the body.

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