Dual role of vascular endothelial growth factor-C in post-stroke recovery.

Cerebrospinal fluid (CSF), antigens, and antigen-presenting cells drain from the central nervous system (CNS) into lymphatic vessels near the cribriform plate and dura, yet the role of these vessels during stroke is unclear. Using a mouse model of ischemic stroke, transient middle cerebral artery occlusion (tMCAO), we demonstrate stroke-induced lymphangiogenesis near the cribriform plate, peaking at day 7 and regressing by day 14. Lymphangiogenesis is restricted to the cribriform plate and deep cervical lymph nodes and is regulated by VEGF-C/VEGFR-3 signaling. The use of a VEGFR-3 inhibitor prevented lymphangiogenesis and led to improved stroke outcomes at earlier time points, with no effects at later time points. VEGF-C delivery after tMCAO did not further increase post-stroke lymphangiogenesis, but instead induced larger brain infarcts. Our data support the damaging role of VEGF-C acutely and a pro-angiogenic role chronically. This nuanced understanding of VEGFR-3 and VEGF-C in stroke pathology advises caution regarding therapeutic VEGF-C use in stroke.