A Hormone is Key to the Lymphatic System

A hormone secreted by cells through the body that plays a role heart disease is also key for proper formation of the lymphatic system, a U.S. study found.

Researchers at the University of North Carolina at Chapel Hill School of Medicine said that targeting the hormone adrenomedullin they may treat the more than 100 million people worldwide affected by lymphedema, a condition that causes painful swelling in arms and legs.

The study, published in the Journal of Clinical Investigation, demonstrated in mice that adrenomedullin peptide is necessary for the lymphatic system — an important part of the body’s immune system.

Senior author Kathleen M. Caron said adrenomedullin is a powerful vascular peptide that can widen existing blood vessels and even promote the growth of new ones, but also controls metabolism, heart rate, thirst and appetite, stress response, antibacterial activity and nerve signal transmission.

The lymphatic system includes lymph nodes and a network of thin tubes that transport fluid and immune cells that have leached out of tissues back into the circulatory system. Between two and three liters of the almost colorless fluid called lymph go through the lymphatic system in a day.

If this system fails, excess fluid collects and swells in tissue, causing lymphedema.