Pituitary adenylate cyclase-activating polypeptide (PACAP) is an endogenous peptide with neuroprotective effects on retinal neurons. Cheng 2018 A remarkable number of studies suggest its importance in the etiology of neurodegenerative disorders, particularly in relation to retinal metabolic disorders. Gábriel 2019
Several studies discussed its neuroprotective effects in neurodegenerative diseases such as in stroke, brain ischemic injuries, Alzheimer’s diseases and in Parkinsonism (Wang et al., 2008; Atlasz et al., 2010; Han et al., 2014; Matsumoto et al., 2016). Gábriel 2019
PACAP "exerts neuroprotective and trophic actions by regulating cell survival and death, not only during the development and maturation of the nervous system but also in pathological conditions." Gábriel 2019
- PACAP has a protective effect during retinal inflammation.
- PACAP contributes to maintaining the biochemical balance within neurons and glial cells.
- in the absence of PACAP aging may accelerate compared to animals with normal PACAP levels.
- PACAP1-38 protects not only neurons, but also the retinal pigmented epithelium both in vivo and in vitro.
- PACAP has a retinoprotective effect in glutamate induced injuries by reducing the pro-apoptotic pathways, while inducing anti-apoptotic signaling.
- and much more
Interestingly, an enriched environment surrounding the experimental animals has also been shown to provide strong protective effect. A combination of enriched environment and PACAP treatment, however, did not further improve the protective effect, suggesting that these two treatments may utilize the same pathway for protection. Gábriel 2019
What are the problems with PACAP?
One of the difficulties of using natural peptides as protective agents is their relatively short half-life. Another potential problem using peptides as therapeutic agents is their limited passage through the blood brain barrier (Banks et al., 1993; Banks and Kastin, 1996) Gábriel 2019
Gábriel 2019 suggests that the challenges can be overcome and that PACAP provides an inexpensive new treatment option.