Biological roles of milk osteopontin.

PURPOSE OF REVIEW

Osteopontin (OPN) is an extensively phosphorylated acidic glycoprotein that is present at high concentration in human milk. Bovine milk OPN has recently become commercially available, and can thus be added to infant formula as well as other food products. Studies in experimental animals as well as a clinical trial in human infants reveal important biological roles for milk OPN.

RECENT FINDINGS

Newborn wild-type mice nursing knock-out dams lacking milk OPN showed impaired cognitive development, reduced brain OPN and myelin-related proteins as compared with pups nursing wild-type dams. Transcriptomic analysis of intestinal biopsies from infant rhesus monkeys fed formula with added bovine milk OPN showed that OPN positively regulated intestinal proliferation, cell migration, and cellular chemotaxis via binding to integrin receptors. A clinical trial on human infants fed formula with added bovine milk OPN showed significantly reduced levels of serum tumor necrosis factor a and fewer days of fever as compared with infants fed regular formula. Further, their immune cell profile was more similar to that of breast-fed infants.

SUMMARY

Milk OPN affects immune functions, and intestinal development in the newborn as well as brain development in a mouse model. Addition of bovine milk OPN to infant formula may improve the performance of formula-fed infants and make them more similar to breast-fed infants. Due to its multiple functions, milk OPN is also used for various adult applications.