Inhibition of neutrophil infiltration by a malleable protein matrix of lactic acid bacteria-fermented whey proteins in vivo

Objective:  A novel nutraceutical ingredient, the Malleable Protein Matrix (MPM), has previously demonstrated a significant anti-inflammatory effect in a systemic inflammatory disease model, comparable to conventional drugs. The objective of this study was to investigate the potential anti-inflammatory effects of MPM on neutrophil infiltration in vivo, phagocytosis activity as well as cytokine and chemokine production. Methods:  Groups of ten C57BL\6J mice received water or MPM per os for a period of 2 weeks prior to the creation of a murine air pouch. The subsequent neutrophil recruitment and activities were characterized following lipopolysaccharide injection. Results:  In the water control group, the number of recruited cells was 1.8X10⁷ cells/pouch, which was reduced to 9X10⁶ cells/pouch with oral MPM consumption, representing an inhibition of 50% of infiltrating leukocytes. A considerable reduction in the cytokine and chemokine production, mostly TNFα, IL-1β and IL-6 production in the MPM-treated group, suggested an inhibition of the mediators responsible for leukocyte extravasation. On the other hand, MPM consumption had no effect on neutrophil phagocytosis activity. Conclusion:  MPM administration demonstrates a significant reduction of neutrophil infiltration associated with an inhibition of cytokine and chemokine production. The air pouch model shares similarities with in vivo characteristics of rheumatoid arthritis and neutrophilic diseases, both of which would benefit from this 50% inhibition of neutrophil infiltration induced by MPM. Received 14 May 2007; returned for revision 7 October 2007; received from final revision 25 April 2008; accepted by S. Stimpson 27 June 2008