Tyrosine Kinase Receptors, Inhibition, and Potential Role in the Pharmacotherapy of Retinal Disorders

Over the past two decades, impressive gains in the restoration and maintenance of visual acuity have been made in patients with, otherwise blinding, chronic retinal diseases such as neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME) using intravitreal pharmacotherapy against vascular endothelial growth factor (VEGF). However, there is serious economic burden, continued potential for risks, and potential drug resistance owing to the necessity of repeated injections so as to sustain the initial gains of therapy. Although efforts such as intravitreal treatment with dual pathway inhibitors and sustained drug release implants have been introduced to address such concerns, they do not seem to be the ideal approaches. Consequently researchers continue to explore more plausible solutions, among which tyrosine kinase inhibition seems to have a strong potential to reduce the treatment burden. In this review, the nature of protein kinases and tyrosine kinases, their receptors, and their downstream signaling effects are discussed, followed by the role of receptor tyrosine kinases (RTK) and their inhibitors in the treatment of retinal diseases such as nAMD and DME.