Lymphedema, or swelling because of the impaired flow of lymph fluid, can occur as a consequence of cancer or cancer treatment. Chemotherapy can damage lymph ducts, and often surgeons remove lymph nodes that may be affected by cancer metastasis. Lymphedema can result in painful swelling, impaired mobility and changes in appearance.
Emory scientists, led by cardiologist and stem cell biologist Young-sup Yoon, have shown that they can isolate progenitor cells for the lining of lymph ducts. This finding could lead to doctors being able to regenerate and repair lymph ducts using a patientâ€™s own cells.Â The results are described in a paper published recently in the journal Circulation.
The authors used the cell surface marker podoplanin as a handle for isolating the progenitor cells from bone marrow. Previous research has demonstrated that podoplanin is essential for the development of the lymphatic system.
In the paper, the authors use several animal models to show that the progenitor cells could contribute to the formation of new lymph ducts, both by becoming part of the lymph ducts and by stimulating the growth of nearby cells.
â€œThis lymphatic vesselâ€“forming capability can be used for the treatment of lymphedema or chronic unhealed wounds,â€ Yoon says.
The authors also show that mice with tumors show an increase in the number of this type of circulating progenitor cells. This suggests that tumors send out signals that encourage lymph duct growth â€“ a parallel to the well-known ability of tumors to drive growth of blood vessels nearby. Yoon says the presence of these cells could be a marker for tumor growth and metastasis.Â Because tumors often metastasize along lymph ducts and into lymph nodes, studying this type of cells could lead to new targets for blocking tumor metastasis.
A recent review in the journal Genes & Development summarizes additional functions of the lymphatic system in fat metabolism, obesity, inflammation, and the regulation of salt storage in hypertension.