Purpose To review para‐inflammatory responses in the ageing retina, and the role of dysregulated para‐inflammation in age‐related retinal degeneration.
Methods Published and unpublished data from personal study in in vivo models and literature review.
Results Para‐inflammation is an immune response to chronic noxious stimuli at a low magnitude that lies between the basal homeostatic state and overt inflammation. The physiological role is to maintain tissue homeostasis and functionality. The retina, particularly the macula, is constantly subjected to a low‐level of insult mediated by oxidized molecules such as unsaturated fatty acid, and the insult accumulates with age. Retinal homeostasis in the ageing eye is maintained by a para‐inflammatory response executed by resident microglia, retinal pigment epithelial (RPE) cells and the complement system. A dysregulated para‐inflammation may not be able to maintain retinal homeostasis, and age‐related retinal degeneration may occur. The presentation will discuss how microglial activation is controlled in the retina, and the potential contribution of uncontrolled microglial activation to age‐related retinal degeneration.
Conclusion Para‐inflammation is important to retinal homeostasis in the ageing eye. Uncontrolled or dysregulated para‐inflammation may contribute to the pathogenesis of age‐related retinal degeneration.