Overview

• The peer‑reviewed findings, led by MDI Biological Laboratory’s Hermann Haller, M.D., and first author Yannic Becker, Ph.D., were published August 21, 2025, in Arteriosclerosis, Thrombosis, and Vascular Biology.
• In zebrafish, loss of Hpa2 increased vascular permeability, while recombinant Hpa2 restored barrier function and blocked VEGF‑induced leakiness in mouse kidneys and human endothelial cell cultures.
• The study shows Hpa2 competes with VEGF and other growth factors for heparan sulfate binding sites on endothelial cells, dampening pro‑permeability signaling.
• Hpa2 is conserved across vertebrates and circulates in the bloodstream, indicating it is a naturally occurring regulator of endothelial integrity.
• Authors highlight pharmaceutical potential for diseases driven by vascular leak, while emphasizing that evidence is experimental and remains at the preclinical stage.