Anne Saaristo

Primary human lymphedema (Milroy's disease), characterized by a chronic and disfiguring swelling of the extremities, is associated with heterozygous inactivating missense mutations of the gene encoding vascular endothelial growth factor C/D receptor (VEGFR-3). Here, we describe a mouse model and a possible treatment for primary lymphedema. Like the human patients, the lymphedema (Chy) mice have an inactivating Vegfr3 mutation in their germ line, and swelling of the limbs because of hypoplastic cutaneous, but not visceral, lymphatic vessels. Neuropilin (NRP)-2 bound VEGF-C and was expressed in the visceral, but not in the cutaneous, lymphatic endothelia, suggesting that it may participate in the pathogenesis of lymphedema. By using virus-mediated VEGF-C gene therapy, we were able to generate functional lymphatic vessels in the lymphedema mice. Our results suggest that growth factor gene therapy is applicable to human lymphedema and provide a paradigm for other diseases associated with mutant receptors.

ABSTRACT Recently, vascular endothelial growth factor receptor 3 (VEGFR‐3) has been shown to provide a specific marker for lymphatic endothelia in certain human tissues. In this study, we have investigated the expression of VEGFR‐3 and its ligands VEGF‐C and VEGF‐D in fetal and adult tissues. VEGFR‐3 was consistently detected in the endothelium of lymphatic vessels such as the thoracic duct, but fenestrated capillaries of several organs including the bone marrow, splenic and hepatic sinusoids, kidney glomeruli and endocrine glands also expressed this receptor. VEGF‐C and VEGF‐D, which bind both VEGFR‐2 and VEGFR‐3 were expressed in vascular smooth muscle cells. In addition, intense cytoplasmic staining for VEGF‐C was observed in neuroendocrine cells such as the α cells of the islets of Langerhans, prolactin secreting cells of the anterior pituitary, adrenal medullary cells, and dispersed neuroendocrine cells of the gastrointestinal tract. VEGF‐D was observed in the innermost zone of the adrenal cortex and in certain dispersed neuroendocrine cells. These results suggest that VEGF‐C and VEGF‐D have a paracrine function and perhaps a role in peptide release from secretory granules of certain neuroendocrine cells to surrounding capillaries.—Partanen, T. A., Arola, J., Saaristo, A., Jussila, L., Ora, A., Miettinen, M., Stacker, S. A., Achen, M. G., Alitalo, K. VEGF‐C and VEGF‐D expression in neuroendocrine cells and their receptor, VEGFR‐3, in fenestrated blood vessels in human tissues. FASEB J. 14, 2087–2096 (2000)

OBJECTIVE: Postoperative lymphedema after breast cancer surgery is a challenging problem. Recently, a novel microvascular lymph node transfer technique provided a fresh hope for patients with lymphedema. We aimed to combine this new method with the standard breast reconstruction. METHODS: During 2008-2010, we performed free lower abdominal flap breast reconstruction in 87 patients. For all patients with lymphedema symptoms (n = 9), we used a modified lower abdominal reconstruction flap containing lymph nodes and lymphatic vessels surrounding the superficial circumflex vessel pedicle. Operation time, donor site morbidity, and postoperative recovery between the 2 groups (lymphedema breast reconstruction and breast reconstruction) were compared. The effect on the postoperative lymphatic vessel function was examined. RESULTS: The average operation time was 426 minutes in the lymphedema breast reconstruction group and 391 minutes in the breast reconstruction group. The postoperative abdominal seroma formation was increased in patients with lymphedema. Postoperative lymphoscintigraphy demonstrated at least some improvement in lymphatic vessel function in 5 of 6 patients with lymphedema. The upper limb perimeter decreased in 7 of 9 patients. Physiotherapy and compression was no longer needed in 3 of 9 patients. Importantly, we found that human lymph nodes express high levels of endogenous lymphatic vessel growth factors. Transfer of the lymph nodes and the resulting endogenous growth factor expression may thereby induce the regrowth of lymphatic network in the axilla. No edema problems were detected in the lymph node donor area. CONCLUSION: Simultaneous breast and lymphatic reconstruction is an ideal option for patients who suffer from lymphedema after mastectomy and axillary dissection.