Objective: To investigate the human milk oligosaccharides (HMOs) levels in breast milk of mothers delivering preterm infants and their effects on the early growth and development of infants. Methods: In this prospective cohort study, full-term and preterm newborns whose parents decided to breastfeed were recruited from Peking University Third Hospital between December 1, 2017 and November 30, 2018. The preterm infants were divided based on their gestational ages into extremely preterm (<28 weeks), very preterm (28-31+6 weeks) and moderate to late preterm (32-36+6 weeks) groups. Breast milk was collected from mothers at 7, 14, 28 and 120d postpartum. 368 breast milk samples were collected from 125 mothers in this study, including 54 mothers of full-term infants, 23 mothers of moderate to late preterm infants, 39 mothers of very preterm infants, and 9 mothers of extremely preterm infants. Ultra-performance liquid chromatography-mass spectrometer (UPLC-MS/MS) was used to determine the concentration of 2'-fucosyllactose (2'FL), 3-fucosyllactose (3FL), 3'-sialyllactose (3'SL), A-tetrasaccharide (P1), lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), lacto-N-fucopentaose Ⅱ (LNFP-Ⅱ) and lacto-N-fucopentaose Ⅴ (LNFP-Ⅴ). Secretor status of mothers was defined as 2'-fucosyllactose (2'FL) concentration in colostrum and transitional milk greater than 200 μg/mL. Weight gain and the occurrence of allergic diseases of infants were collected at 120 d(4 months) postpartum. The chi-square test or the Fisher's exact test was used for the comparison of categorical data between groups; Kruskal-Wallis test and Wilcoxon rank sum test were used for comparison of continuous data between groups. Nemenyi test was used for multiple comparison. Results: 79.2% (99/125) of the mothers were secretor. There were no statistical differences between groups in the secretor status of mothers (χ²=1.31,P>0.05). The total concentration of HMOs peaked at 1-2 weeks postpartum. Compared to the preterm milk, the HMOs from the term milk was trending downwards at an earlier time. In the breast milk of secretor mothers on 28 d, total concentration of HMOs significant differed among the three groups of preterm milk and the term milk, with the median value of 4 587.09,4 615.25,5 277.44,5 476.03 μg/mL, respectively (Kruskal-Wallis χ²=8.1234,P=0.044). When analyzed by the median weight gain of the infants (low vs high weight gain) at 4 months postpartum, 2'FL was significantly lower in the high weight gain group at 7 d (1 818.04 μg/mL vs 2 181.67 μg/mL, W=1 386,P=0.018), while LNT & LNnT were significantly higher (1 182.36 μg/mL vs 1 053.62 μg/mL, W=816,P=0.044). The level of 3FL at 120 d was significantly affected by presence of allergic disease in infants, breast milk from mothers of infants with allergic disease had lower 3FL than those from mothers of infants without allergic disease (256.17 μg/mL vs 286.18 μg/mL, W=564,P=0.026). Conclusions: The overall profiles of HMOs in breast milk of mothers delivering preterm infants was basically the same as that of mothers delivering term infants; individual HMOs play a role in weight gain and the development of allergic diseases in preterm infants, but the mechanism is unclear and needs further study.
目的: 探讨不同胎龄早产儿母乳中母乳低聚糖(human milk oligosaccharides,HMOs)水平及其对婴儿早期生长发育的影响。 方法: 采用前瞻性队列研究,选取2017年12月1日至2018年11月30日期间在北京大学第三医院出生并母乳喂养的新生儿,分为足月儿组和早产儿组。早产儿组分为超早产儿组(<28周)、极早产儿(28~31+6周)组和晚期早产儿(32~36+6周)组。分别在母亲分娩后7、14、28和120 d收集母乳。本研究共收集到125名产妇的368份母乳样品,其中足月儿母亲54名,晚期早产儿母亲23名,极早产儿母亲39名,超早产儿母亲9名;采用超高效液相色谱-质谱仪测定2-岩藻糖乳糖(2′FL),3-岩藻糖乳糖(3FL),3-唾液酸乳糖(3′SL),α-四糖(P1),乳糖-N-四糖(LNT),乳糖-N-新四糖(LNnT),乳糖-N-五糖Ⅱ(LNFP-Ⅱ),乳糖-N-五糖Ⅴ(LNFP-Ⅴ)8种HMOs浓度。以初乳和过渡乳中2-岩藻糖乳糖(2′FL)浓度大于200 μg/mL定义为分泌型母乳。收集婴儿出生后4个月时的体重增长和过敏性疾病发生情况。计数资料组间比较采用χ²检验或Fisher精确检验;计量资料采用Kruskal-Wallis检验和Wilcoxon秩和检验进行组间比较,多组间两两比较采用Nemenyi检验。 结果: 所有产妇中分泌型占79.2%(99/125),不同出生胎龄新生儿母亲分泌型与非分泌型在组间差异无统计学意义(χ²=1.31,P>0.05)。HMOs总浓度在产后1~2周达到峰值,与足月儿相比,早产儿母乳HMOs下降趋势出现较晚,在分泌型分娩后28 d母乳中,晚期早产儿、极早产儿、超早产儿与足月儿组之间HMOs总浓度差异有统计学意义,中位数分别为4587.09、4615.25、5277.44、5476.03 μg/mL(Kruskal-Wallis χ²=8.1234,P=0.044)。按照各组在生后4个月的体重增长中位数,分为低体重增长组和高体重增长组,与低体重增长组相比,高体重增长组分娩后7 d时母乳中2-岩藻糖乳糖(2′FL)偏低(1 818.04 μg/mL vs 2 181.67 μg/mL,W=1386,P=0.018),而乳糖-N-四糖和乳糖-N-新四糖(LNT & LNnT)偏高(1 182.36 μg/mL vs 1 053.62 μg/mL,W=816,P=0.044)。患有过敏性疾病的婴儿母亲分娩后120 d时母乳中3FL含量低于未患有过敏性疾病的婴儿,差异有统计学意义(256.17 μg/mL vs 286.18 μg/mL,W=564,P=0.026)。 结论: 早产儿母乳中HMOs总体分布概况与足月儿基本一致;早产儿母乳中部分HMO在新生儿体重增长及过敏性疾病的发生发展中可能发挥一定的作用。.