Mitogenic activity and epidermal growth factor content in human milk

Area of Science:

• Human milk composition and infant nutrition
• Biochemistry and molecular biology of growth factors

Background:

• Epidermal Growth Factor (EGF) is a vital signaling protein.
• Human milk composition changes significantly from colostrum to mature milk.
• EGF's role in infant development and gut health is increasingly recognized.

Purpose of the Study:

• To quantify and compare epidermal growth factor (EGF) concentrations in human colostral and mature milk.
• To assess the growth-promoting activity of human milk, particularly EGF's contribution.
• To investigate the stability of EGF in mature milk post-pasteurization.

Main Methods:

• Radioimmunoassay (RIA) was employed to determine EGF concentrations.
• 3H-thymidine incorporation assay was used to measure growth-promoting activity in human fibroblasts.
• Analysis included both colostral and mature human milk samples, with and without pasteurization.

Main Results:

• Colostral milk exhibited significantly higher EGF concentrations (25-38 ng/ml) compared to mature milk (5.2-11.5 ng/ml).
• Growth-promoting activity was more pronounced in colostral milk (8.7-fold stimulation) than in mature milk (approx. 7-fold stimulation).
• EGF levels in mature milk were unaffected by pasteurization, and EGF was present in human milk protein preparations.

Conclusions:

• Human colostrum is a richer source of EGF than mature milk, suggesting a critical role in early infant development.
• The high growth-promoting activity in colostrum is partly attributable to its elevated EGF content.
• EGF in mature human milk is stable and retains biological activity even after pasteurization.