The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier (oBRB) and is the prime target of early age-related macular degeneration (AMD). C-reactive protein (CRP), a serum biomarker for chronic inflammation and AMD, presents two different isoforms, monomeric (mCRP) and pentameric (pCRP) that may have a different effect on inflammation and barrier function in the RPE. The results reported in this study suggest that mCRP but not pCRP impairs RPE functionality by increasing paracellular permeability and disrupting the tight junction proteins ZO-1 and occludin in RPE cells. Additionally, we evaluated the effect of drugs commonly used in the clinical setting over the mCRP-induced barrier dysfunction. We found that corticosteroids (methylprednisolone) and anti-VEGF agents (bevacizumab) prevented mCRP-induced ARPE-19 barrier disruption and IL-8 production. Furthermore, bevacizumab was also able to revert mCRP-induced IL-8 increase after mCRP stimulation. In conclusion, the presence of mCRP within retinal tissue may lead to disruption of the oBRB, effect that may be modified in the presence of corticosteroids or anti-VEGF drugs.
- blood-retinal barrier
- C-reactive protein
- tight junctions
- macular degeneration
- Copyright © 2016, American Journal of Physiology-Cell Physiology