The Kiwifruit Peptide Kissper Displays Anti-Inflammatory and Antioxidant Effects in In Vitro And Ex Vivo Human Intestinal Models

BACKGROUND: Literature reports describe kiwifruit as a food with significant effects on human health, including antioxidant and anti-inflammatory activity. Fresh fruit or raw kiwifruit extracts have been used so far to investigate these effects, but the molecule(s) responsible for these health-promoting activities have not yet been identified. Kissper is a kiwifruit peptide displaying pore-forming activity in synthetic lipid bilayers, the composition of which is similar to that found in intestinal cells. OBJECTIVE: To investigate the kissper influence on intestinal inflammation using cultured cells and of ex vivo tissues from healthy subjects and Crohn's disease (CrD) patients. METHODS: The antioxidant and anti-inflammatory properties of kissper were tested on Caco-2 cells and the colonic mucosa from 23 patients with CrD, by challenging with the lipopolysaccharide from Escherichia Coli (EC-LPS) and monitoring the appropriate markers, western blot and immunofluorescence. RESULTS: EC-LPS challenge determined an increase in the intracellular concentration of calcium and the reactive oxygen species (ROS). The peptide kissper was highly effective in preventing the increase of ROS levels LPS-induced in both the Caco-2 cells and CrD colonic mucosa. Moreover, it controls the calcium increase, p65-NF-kB induction and TG2 activation inflammatory response in Caco-2 cells and CrD colonic mucosa. CONCLUSIONS: Kissper efficiently counteract the oxidative stress and inflammatory response in valuable model systems consisting of intestinal cells and CrD colonic mucosa. This study reports the first evidence supporting a possible correlation between some beneficial effects of kiwifruit and a specific protein molecule rather than generic nutrients.