Levels of Cytokines (IL-1β, IL-2, IL-6, IL-8, TNF-α) and Trace Elements (Zn, Cu) in Breast Milk From Mothers of Preterm and Term Infants

摘要

It has been well documented that human milk contains severalimmunomodulator components which are important during infantperiod when the newborn's immune system is still underdevelopment. In this study, we aim at examining levels ofcytokines, zinc (Zn), and copper (Cu) in milk frommothers of premature and mature infants, and comparing changesduring lactation periods consequently. Milk was collected fromtotal of 40 mothers (group M: mothers of mature infants,n=20;group PM: mothers of premature infants,n=20) from fourlactation stages: colostrum (0–7 days), transitional (7–14days), mature milk (21 days), and mature milk (2nd month). Levelsof cytokines (interleukin [IL]-lβ, IL-2, IL-6, IL-8, tumornecrosis factor-alpha [TNF-α]) were determined bychemiluminesence method, whereas atomic absorptionspectrophotometer was used for the determination of Zn andCu levels. Cytokine levels were determined to behigh in colostrum and transient milk from mothers of full-terminfants, whereas their levels were reduced drastically in the 21stday and the 2nd month milk (P<.01,P<.001). Similartrends were observed in milk from mothers of premature infants,but cytokine levels were significantly lower in colostrum comparedto colostrum from mothers of mature infants (P<.01). Thedifferences in cytokine levels were continuous in transient milk(P<.05) and mature milk (21 days) (P<.05), whereas there wasno statistically significant differences between milk from bothgroups of mothers in the 2nd month (P>.05). Zn levels inmilk from mothers of premature infants were significantly lowercompared to the ones from mothers of mature infants (P<.01) andthese differences continued through the 2nd month. AlthoughCu levels were lower in milk from mothers of prematureinfants, there was no statistically significant difference exceptcolostrum (P>.05). Our results clearly demonstrate that thelevel of immunomodulating agents such as cytokines and traceelements in milk from mothers of premature infants is less thanthe level of the same agents in milk from mothers of full-terminfants. Although there are commercially available products forinfant feeding, human milk is still the best natural nutrient fornewborns. Therefore, when premature infants are breastfed,necessary precautions such as supplemantary diets must beconsidered for possible infections and risks related with immunesystem deficiency.