Comparison of Colony-forming Efficiency between Breast Milk Stem/progenitor Cells of Mothers with Preterm and Full-term Delivery

Background: The beneficial effect of breastfeeding for the health of mothers and infants are well recognized. Breast milk is a novel source of the stem cells forming during pregnancy and lactation. In the present study, the colony forming efficiency (CFE) of breast milk-derived stem/progenitor cells in the breast milk of mothers with preterm delivery (gestational age of fewer than 37 weeks) was compared with that of mothers with full-term delivery (gestational age of more than 37 weeks). Methods: Fresh-pumped breast milk of 30 healthy mothers with full-term delivery and 30 mothers with preterm delivery who had no underlying illness and drug intake were collected on days 5 and 15 after delivery, and then immediately assessed. For the purpose of the study, 10 ml fresh breast milk was gently mixed with equal amount of phosphate buffer saline, centrifuged at 1,380 rpm for 20 min, cultivated in 1 ml MethoCult H4435 medium (Stem Cell Technologies), and incubated at 37°C with 5% CO2 and 80% humidity for 14 days. Results: The CFE is significantly lower in the 25 to 35-year-old mothers on day 15 after delivery than in 35 to 45-year-old mothers (P=0.01). In both groups of mothers, the CFE was higher on day 5 than on day 15. Moreover, a significant correlation was observed between the CFE of breast milk stem/progenitor cells obtained on days 5 and 15 with the infants weighing 3,000-4,000 g (130±62, P=0.03 and 105±26, P=0.021), respectively. Furthermore, CFE increased in the breast milk of mothers aged 35 > years in comparison to that of younger mothers. Conclusion: According to our analysis, breast milk stem/progenitor cells CFE was higher in mothers with preterm delivery than in mothers with full-term delivery. These observations may uncover the compensatory mechanisms illustrated in the mothers' breast milk to improve the preterm infants' tissues development and organ formation in which various factors were involved, such as mothers' age and infants' weight.