Diabetic retinopathy is the leading cause of blindness in working-age adults. The dominant therapeutic target for decades has been VEGF — vascular endothelial growth factor — which drives the abnormal blood vessel growth that eventually destroys the retina. Anti-VEGF injections work for about half of patients and rarely reverse existing damage.
Researchers at UCL found that a different protein, LRG1, initiates retinal damage before VEGF is even induced. In diabetic mice, LRG1 levels rose first. It modified TGF-beta signaling in pericytes — the contractile cells that wrap around capillaries — driving them toward a fibrotic phenotype. The pericytes contracted. Capillaries narrowed. Basement membranes thickened. Oxygen delivery dropped. The retina began starving before VEGF entered the picture.
By the time anti-VEGF therapy is administered, the damage initiated by LRG1 has been accumulating for years. The treatment targets the consequence, not the cause. It addresses the fire while ignoring the spark.
The researchers have already developed an LRG1-targeting antibody. In preclinical models, blocking LRG1 halted the earliest vascular changes. It prevented the cascade rather than managing it downstream.
The through-claim: the search criterion excluded the answer. Decades of retinopathy research focused on VEGF because VEGF drives the visible pathology — the hemorrhages, the neovascularization, the edema. But the visible stage is not the first stage. Defining the disease by its late symptoms directed the search to a late target. The earlier trigger was upstream of the spotlight, which is exactly where the spotlight doesn't reach.