A literature review on lactopontin and its roles in early life

An expert panel on the adequacy of safety data and physiological roles of dietary bovine osteopontin in infancy

Human milk, due to its unique composition, is the optimal standard for infant nutrition. Osteopontin (OPN) is abundant in human milk but not bovine milk. The addition of bovine milk osteopontin (bmOPN) to formula may replicate OPN's concentration and function in human milk. To address safety concerns, we convened an expert panel to assess the adequacy of safety data and physiological roles of dietary bmOPN in infancy. The exposure of breastfed infants to human milk OPN (hmOPN) has been well-characterized and decreases markedly over the first 6 months of lactation. Dietary bmOPN is resistant to gastric and intestinal digestion, absorbed and cleared from circulation within 8-24 h, and represents a small portion (<5%) of total plasma OPN. Label studies on hmOPN suggest that after 3 h, intact or digested OPN is absorbed into carcass (62%), small intestine (23%), stomach (5%), and small intestinal perfusate (4%), with <2% each found in the cecum, liver, brain, heart, and spleen. Although the results are heterogenous with respect to bmOPN's physiologic impact, no adverse impacts have been reported across growth, gastrointestinal, immune, or brain-related outcomes. Recombinant bovine and human forms demonstrate similar absorption in plasma as bmOPN, as well as effects on cognition and immunity. The panel recommended prioritization of trials measuring a comprehensive set of clinically relevant outcomes on immunity and cognition to confirm the safety of bmOPN over that of further research on its absorption, distribution, metabolism, and excretion. This review offers expert consensus on the adequacy of data available to assess the safety of bmOPN for use in infant formula, aiding evidence-based decisions on the formulation of infant formula.

Gastro-Intestinal Digested Bovine Milk Osteopontin Modulates Gut Barrier Biomarkers In Vitro

SCOPE

Osteopontin (OPN) is a multifunctional protein naturally present in mammals' milk, associated with immune homeostasis and intestinal maturation. This study aims to investigate the protein digestion pattern and the cellular bioactivity of bovine milk OPN digesta in vitro.

METHODS AND RESULTS

A modified INFOGEST static in vitro infant digestion protocol and a Caco-2/HT-29 co-culture cell model are employed to evaluate the digestion properties and the anti-inflammatory effects of OPN. OPN is resistant to gastric hydrolysis but degraded into large peptides during intestinal digestion. Its 10 kDa digesta permeate with predicted extensive bioactivities protects the co-culture cell model from the inflammation-induced dysfunction by dose-dependently recovering the expression of occludin, claudin-3, and ZO-1. Low dosage of OPN significantly decreases the production of IL-8 and IL-6, and downregulates the mRNA and protein expression of MyD88, NF-κB p65, and IκB-α, whereas a high dose evokes a mild pro-inflammatory response. Interestingly, anti-inflammatory effect of OPN digesta is stronger than lactoferrin and whey protein concentrate counterparts.

CONCLUSION

The findings demonstrate that the bioactive peptides released from in vitro infant gastrointestinal digestion of bovine milk OPN alleviates intestinal epithelial cell inflammation by inhibiting NF-κB pathway activation and potentiates the barrier function of the intestinal epithelium.

Milk Osteopontin and Human Health

Osteopontin (OPN) is a multifunctional protein found in all vertebrates. OPN is expressed in many different cell types, and is consequently found in most tissues and physiological secretions. OPN is involved in a multitude of biological processes, such as activation and regulation of the immune system; biomineralization; tissue-transformative processes, including growth and development of the gut and brain; interaction with bacteria; and many more. OPN is found in the highest concentrations in milk, where it is believed to initiate and regulate developmental, immunological and physiological processes in infants who consume milk. Processes for the isolation of bovine OPN for use in infant formula have been developed, and in recent years, many studies have investigated the effects of the intake of milk OPN. The purpose of this article is to review and compare existing knowledge about the structure and function of milk OPN, with a particular focus on the effects of milk OPN on human health and disease.