BackgroundHigh hyperbaric pressure treatment of whey protein isolate (WPI) causes changes in the protein structure that enhances the anti-oxidant and anti-inflammatory effects of WPI.ObjectiveThe aim of this study was to compare the anti-oxidant and anti-inflammatory effects of pressurized whey protein isolate (pWPI) vs. native WPI (nWPI) hydrolysates in Caco-2 cells exposed to hydrogen peroxide (H2O2).DesignCells were cultured with different concentrations of pWPI or nWPI hydrolysates either 1 h before or 1 h after H2O2. Cell viability, IL-8 secretion, intracellular reactive oxygen species (ROS), and the medium anti-oxidant capacity (FRAP assay) were measured.ResultsPrior to and after H2O2 exposure, pWPI and nWPI hydrolysates inhibited IL-8 secretion and ROS generation, and increased FRAP activity in a dose-dependent manner. The maximal inhibition of H2O2-induced IL-8 secretion was greater with 2000 µg mL−1 of pWPI (50%) vs. nWPI (30%) hydrolysates. At the latter concentration, inhibition of H2O2-induced ROS formation reached 76% for pWPI, which was greater than for nWPI hydrolysates (32.5%).ConclusionsThese results suggest that WPI hydrolysates can alleviate inflammation and oxidative stress in intestinal cells exposed to oxidative injury, which is further enhanced by hyperbaric pressure pre-treatment of WPI.

Whey proteins (WP) exert anti-inflammatory and antioxidant effects. Hyperbaric pressurisation of whey increases its digestibility and changes the spectrum of peptides released during digestion. We have shown that dietary supplementation with pressurised whey improves nutritional status and systemic inflammation in patients with cystic fibrosis (CF). Both clinical indices are largely affected by airway processes, to which respiratory epithelial cells actively contribute. Here, we tested whether peptides released from the digestion of pressurised whey can attenuate the inflammatory responses of CF respiratory epithelial cells. Hydrolysates of pressurised WP (pWP) and native WP (nWP, control) were generated in vitro and tested for anti-inflammatory properties judged by the suppression of IL-8 production in CF and non-CF respiratory epithelial cell lines (CFTE29o-and 1HAEo-, respectively). We observed that, in both cell lines, pWP hydrolysate suppressed IL-8 production stimulated by lipopolysaccharide (LPS) to a greater magnitude compared with nWP hydrolysate. Neither hydrolysate suppressed IL-8 production induced by TNF-a or IL-1b, suggesting an effect on the Toll-like receptor (TLR) 4 pathway, the cellular sensor for LPS. Further, neither hydrolysate affected TLR4 expression or neutralised LPS. Both pWP and nWP hydrolysates similarly reduced LPS binding to surface TLR4, while pWP tended to more potently increase extracellular antioxidant capacity. In conclusion: (1) anti-inflammatory properties of whey are enhanced by pressurisation; (2) suppression of IL-8 production may contribute to the clinical effects of pressurised whey supplementation on CF; (3) this effect may be partly explained by a combination of reduced LPS binding to TLR4 and enhanced extracellular antioxidant capacity.

Background: High-dose ibuprofen is clinically effective in cystic fibrosis (CF); however, its molecular mechanisms are poorly understood. Objective: To test the hypothesis that clinically relevant concentrations of ibuprofen suppress activation of nuclear factor (NF)-ĸB and thus down-regulate stimulated interleukin (IL)-8 production in CF respiratory epithelial cells. Methods: The majority of experiments were conducted in CFTE29o– cells (F508del-mutated CF transmembrane regulator, CFTR). Key experiments were confirmed in CFBE41o– cells (F508del-mutated CFTR) and 1HAEo– cells (wild-type CFTR). NF-ĸB and IL-8 were stimulated with tumour necrosis factor (TNF)-α or IL-1β. NF-ĸB and IL-8 suppression by ibuprofen (480 µM) was compared to dexamethasone (5 nM). Results: Both TNF-α and IL-1β activated NF-ĸB and stimulated IL-8 production. Both ibuprofen and dexamethasone demonstrated comparably modest suppression of NF-ĸB transcriptional activity. However, ibuprofen had no effect on stimulated IL-8 mRNA and protein. By contrast, dexamethasone significantly down-regulated stimulated IL-8 mRNA and protein. Conclusions: The present data do not support the hypothesis that ibuprofen down-regulates IL-8 production in response to TNF-α and IL-1β in CF respiratory epithelium. Suppression of NF-ĸB transcriptional activity does not discriminate between anti-inflammatory drugs with or without effects on IL-8 production. We speculate that NF-ĸB-independent mechanisms may be responsible for anti-IL-8 effects of dexamethasone.

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