Erythropoietin

The function of EPO

EPO is mainly produced in the kidneys and released into the blood. There it binds to special receptors on the precursor cells of the red blood cells in the bone marrow and stimulates their growth and maturation. The amount of EPO in the blood is regulated by the oxygen content in the tissue: If the oxygen level is too low, for example in the case of blood loss, anemia or altitude adaptation, more EPO is released to increase the production of red blood cells. If the oxygen level is normal or too high, less EPO is released to prevent overproduction of red blood cells.

The diseases of EPO

There are several diseases that can be associated with impaired EPO production or action. The most common are

• Chronic kidney disease: the kidneys are the main source of EPO for most dogs. When kidney function is impaired by a chronic disease such as diabetes, high blood pressure, inflammation or stones, EPO deficiency can occur. This leads to a reduced formation of red blood cells and anemia, i.e. a lack of red blood cells in the blood. Anemia can cause symptoms such as fatigue, weakness, loss of appetite, weight loss, pale mucous membranes and palpitations.
• Polycythemia: This is a condition in which there are too many red blood cells in the blood. This can have various causes, for example increased EPO production due to a tumor in the kidney or other organs, a reduced oxygen supply due to heart or lung disease or a genetic predisposition. Polycythemia can make the blood thicker and increase the risk of thrombosis and strokes. Symptoms can vary depending on the severity, but typically include reddening of the mucous membranes, shortness of breath, sluggishness, cyanosis (blue coloration) and seizures.

The treatment of EPO

The treatment of EPO disorders depends on the underlying cause and the severity of the symptoms. The most important treatment options are

• EPO substitution: if the kidneys can no longer produce enough EPO, artificial administration of EPO can help to correct the anemia and improve the dog's quality of life and vitality. To do this, the dog is regularly injected with synthetic EPO under the skin. The dosage must be adjusted individually and depends on the haemoglobin level in the blood. EPO therapy can have side effects such as an overproduction of red blood cells, the formation of antibodies against the synthetic EPO or an allergic reaction. The dog must therefore be closely monitored.
• Phlebotomy: If the dog has too many red blood cells, a blood sample can help to thin the blood and reduce the risk of thrombosis. This involves taking a certain amount of blood from the dog and replacing it with a saline solution. The phlebotomy must be repeated as necessary and can have side effects such as anemia, infections or circulatory problems.
• Treatment of the underlying disease: The best way to prevent or treat EPO disorders is to tackle the cause. This includes, for example, appropriate treatment of diabetes, high blood pressure, inflammation or tumors that can impair kidney function. A change in diet, adequate fluid intake, iron or vitamin D supplementation or oxygen therapy can also be helpful, depending on the case.