ADCYAP1 and diabetes mellitus: Based mainly on the cytoprotective functions of PACAP, there are several promising data for its potential future therapeutic use, such as in diabetes (117), multiple sclerosis (118), the intranasal administration in neurodegenerative diseases, cognitive impairment and stroke (119–121), in form of eye drops in corneal and retinal lesions (122, 123) and dry eye disease (124).