Endothelin

What is endothelin?

Endothelin (ET) is a peptide (small protein) that helps regulate your blood pressure by constricting (tightening) your blood vessels. Peptides are small proteins made up of short chains of amino acids (organic compounds). Your endothelium (the cells lining the inside of your blood vessels) makes endothelin. This smaller protein serves as a building block for larger proteins in your body.

What is the endothelium?

Your endothelium is a thin layer of endothelial cells that line the inside of your blood vessels. It is your body’s largest organ. Endothelial cells release substances that control vascular tone, or the opening (dilation) and closing (constriction) of arteries. Vascular tone determines how hard your heart works to pump blood and circulate it through your body.

The endothelium and endothelin also:

• Aid blood clotting.
• Control fluid and electrolyte levels in your blood.
• Regulate inflammation by keeping toxins out of tissues.

What does endothelin do?

Endothelins are your body’s most powerful vasoconstrictor. Vasoconstriction increases your blood pressure. To break it down:

• Vaso refers to blood vessels in your cardiovascular system.
• Constrictor (or constriction) refers to the narrowing of blood vessels, which slows or stops blood flow.

How does endothelin affect your body?

Elevated levels of endothelin can cause conditions that damage your heart and lungs. These conditions include:

• Atherosclerosis (arterial disease).
• Broken heart syndrome.
• Cancer.
• Cardiomyopathy.
• Cardiovascular (heart) disease and heart failure.
• Coronary artery disease, including endothelial dysfunction.
• High blood pressure and preeclampsia.
• Kidney disease and kidney failure.
• Pulmonary fibrosis and pulmonary hypertension.
• Scleroderma.

What are the types of endothelin?

Medical researchers first identified endothelins in 1987. Four different amino acid peptides make up three types of endothelins, which are all vasoconstrictors. The most common and strongest endothelin in your body is endothelin-1 (ET-1). Researchers are still learning how the ET-2 and ET-3 types affect your body.

What are endothelin receptors?

All tissues have endothelin receptors. These receptors bind to endothelins, helping them communicate with cells throughout your body.

How do healthcare providers measure endothelin levels?

A blood test measures ET-1 in plasma. Plasma is the liquid part of your blood that remains after a lab removes platelets and white and red blood cells. A blood test may take place in your healthcare provider’s office, a hospital or a lab. Blood tests are unable to detect the other types of endothelins.

Healthcare providers measure endothelin in picograms per milliliter (pg/mL). In adults, a normal ET-1 plasma level is 1 pg/mL to 2 pg/mL. ET-1 levels are higher in children. These levels also vary among different races.

Elevated ET-1 levels are found in certain heart or lung conditions such as pulmonary arterial hypertension. Certain heart procedures like balloon angioplasty can raise endothelin levels.

What do endothelin receptor antagonists do?

Endothelin receptor antagonists (ERA) are medications that lower the amount of endothelin in your body. They’re a type of targeted therapy, which means they identify and attack certain problem cells without damaging healthy ones. ERAs are used in the treatment of certain types of pulmonary arterial hypertension.

What are the side effects of endothelin receptor antagonists?

Females who are pregnant or planning to become pregnant shouldn’t take ERAs because the drugs can cause birth defects.

In rare instances, the medications can damage your liver. Your healthcare provider may order more frequent blood tests to monitor the health of your liver.

Other potential side effects of ERAs include:

• Constipation.
• Facial swelling (edema) or flushing.
• Headaches.
• Nausea and vomiting.
• Rapid pulse and heart rate.

A note from Cleveland Clinic

Endothelin helps regulate your blood pressure by constricting your blood vessels. When your endothelin levels get too high, your blood vessels constrict more than they should. This can lead to blood pressure problems, as well as heart and lung conditions. You may need to take endothelin receptor antagonists (ERAs) to lower the amount of endothelin in your blood. A blood test checks endothelin levels in plasma.