Articles on Lymphedema Nature Published online: 27 July ; doi Phyllida Brown reports. Circulation warWe are all familiar with the blood circulatory system. But its 'twin', the lymphatic system has been neglected in the past. Not now though, as cancer biologists, developmental biologists and even palaeontologists begin to show that it has many vital functions Sometimes it's hard to be a scientist.
Just five years ago, Mihaela Skobe, a molecular biologist now at Mount Sinai School of Medicine in New York, and her team were struggling to publish their work on the lymphatic system. Editors and reviewers thought it boring. The polite but yawning rejection letters came. Once dismissed as a mere drainage network, the body's 'second circulation' system see Graphic, below is emerging as a crucial player in numerous diseases from cancer to asthma, and as a vital part of the normal immune system.
As a result of these discoveries, researchers are trying to intervene in its activities, for example to reduce the spread of tumours, to boost the efficiency of vaccines, or to treat the painful and disfiguring swelling known as lymphoedema. These days, he says, many laboratories are switching from the study of blood vessels to the lymphatic system. Detmar is one of several researchers showing how important the lymphatic system is for tumour spread. Other groups are finding it plays a key role in inflammatory diseases such as asthma or transplant rejection.
Lymphatic vessels may be drains, but they are pretty sophisticated ones. Not only do they collect fluid that has leaked into tissues from the bloodstream and return it to the blood; they also process that fluid, sending it through lymph nodes where key cells of the immune system, called dendritic cells, present fragments of foreign molecules to other cells to mount an immune response. But the fact is that the lymphatic system has played second fiddle to the blood system for centuries.
Only properly discovered in the s see A brief history of our second circulation , it faded into obscurity and, apart from a brief flurry of interest around , was largely neglected until about ten years ago.
