Molecular Classification
Barrier, Endothelium, Epithelium, Tight Junction
Disease Roles
Diabetic retinopathyAge-related macular degenerationUveitis

Blood-Retinal Barrier Overview

The blood-retinal barrier (BRB) is a critical physiological structure that maintains the specialized environment of the retina, essential for proper visual function. It acts as a selective barrier, regulating the movement of solutes, nutrients, and fluids between the bloodstream and retinal tissue while preventing potentially harmful substances from entering the retina. The BRB consists of two main components: the inner blood-retinal barrier (iBRB), formed by non-fenestrated endothelial cells lining retinal capillaries, and the outer blood-retinal barrier (oBRB), composed of retinal pigment epithelial (RPE) cells joined by tight junctions. Disruption or breakdown of either component leads to increased vascular permeability—an underlying factor in several sight-threatening diseases.

Mechanism of Action

Therapeutic strategies often target pathways involved in barrier breakdown to restore integrity or modulate it for drug delivery purposes, e.g., by inhibiting VEGF.

Biological Functions

Homeostasis maintenance
Selective permeability
Nutrient/waste exchange regulation
Protection against toxins/pathogens

Disease Associations

Diabetic retinopathy
Age-related macular degeneration
Uveitis
Retinal vein occlusion
Macular edema

Safety Considerations

  • Modulation of barrier function for drug delivery must be carefully controlled to avoid unintended consequences.