Inflammatory modulation effects of human milk oligosaccharides: from screening in-vitro to application in the milk powders

Human milk oligosaccharides (HMOs) are significant constituents of breast milk and have potential anti-inflammatory bioactivities. We compared the immunomodulatory effects of lacto-N-biose I (LNB), lacto-N-triose II (LNT II), galacto-oligosaccharides (GOS), and their combinations (GOS+LNB, GOS+LNT II, LNB+LNT II, m/m=1:1) in lipopolysaccharide-induced RAW264.7 macrophages. LNT II and LNB+LNT II efficiently inhibited inflammation-related gene expression and enhanced phagocytosis and anti-inflammatory ability, which may be attributed to their N-acetylglucosamine structure. Three milk powder prototypes (control, LNT II, and LNB+LNT II) were formulated and characterized, exhibiting favorable physicochemical properties. In-vitro simulated digestion coupled with caucasian colon adenocarcinoma (Caco-2) inflammation model demonstrated that the milk powder digestives inhibited tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) release while promoting interleukin-10 (IL-10) production. The digestives of the three milk powders could also inhibit the decrease in transmembrane electrical resistance and the increase in intestinal permeability, playing a crucial role in maintaining intestinal homeostasis. This study will contribute to the functional evaluation and product development of HMOs and inform milk powder design.