In a study published by the leading multidisciplinary science journal Nature, an international team of scientists led by the University of South Australia have made a major discovery revealing that lymphatic vessels can produce red and white blood cells.
Until now, it was believed that blood cells were derived solely from stem cells found in the bone marrow.
Researchers made the connection when studying lymphoedema, which causes a blockage in the lymphatic system resulting in swelling of the arm or leg, which is challenging to treat.
Lymphatic vessels are a vital component of the cardiovascular system responsible for returning excessive tissue fluid and protein back into the bloodstream and forming a major part of the immune system that defends the body against harmful bacteria and viruses.
Developmental biologist and Centre for Cancer Biology Director Professor Natasha Harvey and colleagues traced defects in the lymphatic vessels to cells being incorrectly programmed during development.
“We discovered a site in DNA important for controlling genes that program the identity and development of lymphatic vessels,” Prof Harvey says.
“If these genes aren’t switched on at the correct time and place, lymphatic vessels don’t form properly, causing lymph fluid to leak back into the tissues, leading to swelling (lymphoedema). In an unexpected discovery, we identified that the same gene that controls the development of lymphatic vessels also controls the production of blood cells.
“This exciting discovery suggests that lymphatic vessels may be a previously unrecognised source of blood cells both during development and in disease.”
The ability of the lymphatic vessels to produce blood cells could be important for fighting infection and may play a role in some blood cancers. However, the researchers will not target what triggers the lymphatic vessels to produce different types of blood cells and when this occurs.
