What actually is the hormone erythropoietin (EPO) and what role does it play in connection with kidney disease?
What exactly is EPO anyway?
EPO has become famous mainly because of its use in doping for cyclists. EPO is actually a natural hormone that is formed in the kidney and subsequently controls the production of your red blood cells. In the case of kidney insufficiency, there is often less production of EPO, which can subsequently lead to anemia. In this article you can find out which medications can help here.
Anemia in kidney disease
Many people with kidney disease have anemia. Anemia is a lack of red blood cells. In chronic kidney disease, with a glomerular filtration rate (eGFR) between 30 and 59 ml/min, anemia affects as many as 20 to 40% of people. With an eGFR of less than 30 ml/min including dialysis requirement, this figure already rises to over 70%. This deficiency often manifests itself in a drop in the hemoglobin (Hb) value. But this is no reason to worry! You will learn later in this article what you can do about it.
Hemoglobin is a protein and makes up about 90% of the dry mass of your red blood cells (=erythrocytes). It gives your blood, together with the iron it contains, its typical red color. Its action is extremely important for your body. In your red blood cells it absorbs oxygen (=O2) from the air you breathe in the vessels of your lungs and transports it to the various organs of your body. Once there, it then absorbs carbon dioxide (=CO2) and transports it back to the lungs, where it is exhaled.
Renal anemia & human blood formation
To prevent your body from becoming anemic, it is extremely important that new blood is produced. Over the course of a month, your body produces more than a liter of new blood. This blood formation takes place mainly in the bone marrow. Old red blood cells that no longer fulfill their function properly are sorted out and replaced. A red blood cell usually has a life span of about 120 days. When this lifespan is over, the iron they contain is recycled to form new red blood cells.
This blood formation is driven and regulated by hormones. One of them is erythropoietin (EPO), which is produced in the kidney. In chronic kidney failure, your kidney, in addition to losing its ability to filter the blood, also loses its ability to make enough EPO. This leads to anemia. In order to prevent this so-called renal anemia, it is extremely important that you take the right therapeutic measures with the support of your doctor. Before we go through these measures together, let's first take a look at the range in which your Hb values should ideally be.
Target value for hemoglobin (Hb)
In healthy people, anemia is defined by the World Health Organization (WHO) when Hb levels are below 13 g/dL for men and 12 g/dL, for women. The most common causes of anemia in the population are not EPO deficiency, but iron deficiency which accounts for almost 80% of cases. Worldwide, it is estimated that about 2 billion people are affected by iron deficiency. In Europe, just under 10% of women of childbearing age are affected.
In people with kidney disease, there is sometimes no iron deficiency, because the stores are often relatively full. However, the available iron is difficult to mobilize and use for blood formation. This is why we also speak of a functional iron deficiency. Therefore, iron administration of "mobile iron" via your bloodstream or in tablet form can also be useful in kidney disease.
The KDIGO guidelines recommend a target Hb value between 10 and 11.5 g/dl for chronic renal impairment if EPO therapy is necessary. An Hb value of 13 g/dl should not be exceeded by the administration of EPO.
Therapy of renal anemia
So now you know in which range your Hb value should be. Now the question remains how you can improve your EPO and iron levels:
1. EPO therapy
If your Hb level is below 10 g/dL, you should start with drugs that have a stimulating effect on blood formation (Erythropoesis-Stimulating Agent; ESA). The best known ESA is the hormone EPO, which you already know. For many years now, EPO can be produced by genetic engineering.
It helps to stimulate blood formation in an artificial way if the patient's own production of the hormone is lacking. Most preparations are based on the body's own EPO, have the same effect and are administered to your body via an injection. In the meantime, modified active ingredients, which work like EPO, but have a longer duration of action, are also on the market.
According to information from the manufacturers, most EPO preparations can be injected under the skin or into a vein. The effect is often better with an injection under the skin. The injections can also be performed independently with a little practice. Please do not worry about this. Your attending physician will accompany you throughout the entire therapy and will adequately clarify all your questions.
All medications should be stored in a cool place and placed in a cooler bag for transport. At the beginning of EPO therapy, your blood pressure may also rise, which is why it is necessary to monitor your blood pressure closely.
2. Iron therapy
Together with EPO, iron should also be replaced. Iron substitution in renal failure can be done either by tablets or by vein. Before EPO preparations are given, iron stores should be filled. Iron can be given in the form of capsules or via the vein.
Iron is needed for the formation of new red blood cells. Absorption in the form of capsules is often' not sufficient on its own, which is why administration via the vein is necessary. This can usually be done via an infusion at your doctor's office. This also reduces the flood of tablets in kidney disease a little. Iron can be administered during dialysis. Here, too, your attending physician is available to answer any questions you may have and will advise you in advance on the best solution for you. It is important that you always report to your physician immediately if any side effects occur in connection with iron therapy. This is especially true for gastrointestinal disorders and constipation caused by taking iron capsules or allergic reactions after iron is administered by vein. These can occur when the iron runs into your blood too quickly. Signs include nausea, vomiting, flushing, or circulation problems. These symptoms can be counteracted by adjusting the iron administration.
So you see there are ways to manage your EPO and iron levels. Together with your medical team you can find out the most suitable therapy for you, so that your body can produce new blood.
Note: This article is for educational and knowledge purposes only. This article is in no way intended to recommend or evaluate specific classes of medications. If you have any questions about taking medications, you should always contact your medical team.
