What does hepcidin do in the body?

            The human body system consists of numerous systems which play a variety of roles in allowing humans to live and survive. One of the systems called the blood circulatory system plays a role in providing oxygen and nutrients for the cell in the body. It also eliminates waste products from the body metabolism. The blood circulatory system in humans is rather complex as it does not only involve the blood vessels, but also the heart in allowing pumping of the blood. In this article, we will be talking more about a substance called hepcidin that exists in the human body which helps the body regulate iron that affects the blood.

            Hepcidin is a hormone produced by the liver and is secreted into the blood system. It is known as the master regulator of systemic iron homeostasis that influences production of the red blood cells. It helps maintain the iron balance in the body by controlling the body on how to efficiently use the iron supply. Iron is needed for production of haemoglobin, a protein in red blood cells. Haemoglobin is vital for enabling red blood cells to transport oxygen in the blood from the lungs to the tissue.

            Thus, what does hepcidin do in the body? Hepcidin regulates the iron in the body by preventing processes that allow the body to absorb iron. Hepcidin acts on a protein called ferroportin. Ferroportin is also known as an iron exporter. An iron exporter works by acquisition and transferring iron between cells. When hepcidin acts on ferroportin, it induces its degradation or breakdown, thus preventing iron entry into the bloodstream from being absorbed in the small intestine.

            This mechanism makes hepcidin the iron regulator. Aside from regulating iron absorption, it also functions as releasing the stored iron from the liver cells (hepatocytes) and small intestines (enterocytes). For instance, when a person experiences low oxygen levels (hypoxia), the body needs oxygen to recover from this condition. Low oxygen triggers the hepcidin to be decreased. This causes ferroportin to transport more iron to the bloodstream to make haemoglobin. When haemoglobin increases, transport of the oxygen also increases. This also prevents the body from absorbing too much iron. Excessive iron may lead to life-threatening conditions such as heart and liver problems.

       Another function of hepcidin is to recycle the iron in macrophages. Macrophages are white blood cells that work by eliminating the old red blood cells. The macrophages bind with iron from the haemoglobin of the old red blood cells and destroy it. After about four months, iron is recycled from the dying red blood cells by the, ready to be reused. Apart from macrophages, the spleen and liver also are involved with recycling iron. Role of hepcidin is significant for conservation of iron because dietary iron is merely enough to make up for small losses of iron. Lost iron can be found in the skin cells (epithelial) and the red blood cells are then eliminated into the urine or faeces.

       By knowing what hepcidin does to the body, it helps us understand medical conditions affected by the hormone. Low levels of hepcidin are commonly associated with iron-deficiency anaemia as it shows that the body does not absorb enough iron. High levels of hepcidin are associated with non-iron deficiency anaemia such as anaemia of chronic disease like those with chronic infections or chronic kidney disease. Inflammation and infection also increase the level of hepcidin. In these conditions, hepcidin production is not regulated by the iron status of the body, but is affected by the stimulation of a chemical called cytokines. Cytokines are a product from the body’s immune response, causing changes of the cells.