Many molecular components in human milk (HM), such as human milk oligosaccharides (HMOs), assist in the healthy development of infants. It has been hypothesized that the functional benefits of HM may be highly dependent on the abundance and individual fine structures of contained HMOs and that distinctive HM groups can be defined by their HMO profiles. However, the structural diversity and abundances of individual HMOs may also vary between milk donors and at different stages of lactations. Improvements in efficiency and selectivity of quantitative HMO analysis are essential to further expand our understanding about the impact of HMO variations on healthy early life development. Hence, we applied here a targeted, highly selective, and semi-quantitative LC-ESI-MS² approach by analyzing 2 × 30 mature human milk samples collected at 6 and 16 weeks post-partum. The analytical approach covered the most abundant HMOs up to hexasaccharides and, for the first time, also assigned blood group A and B tetrasaccharides. Principal component analysis (PCA) was employed and allowed for automatic grouping and assignment of human milk samples to four human milk groups which are related to the maternal Secretor (Se) and Lewis (Le) genotypes. We found that HMO diversity varied significantly between these four HM groups. Variations were driven by HMOs being either dependent or independent of maternal genetic Se and Le status. We found preliminary evidence for an additional HM subgroup within the Se- and Le-positive HM group I. Furthermore, the abundances of 6 distinct HMO structures (including 6′-SL and 3-FL) changed significantly with progression of lactation.

母乳 (HM) 中的许多分子成分，例如母乳低聚糖 (HMO)，有助于婴儿的健康发育。据推测，HM 的功能优势可能高度依赖于所含 HMO 的丰度和个体精细结构，并且独特的 HM 组可以通过它们的 HMO 配置文件来定义。然而，个体 HMO 的结构多样性和丰度也可能因牛奶捐赠者和不同泌乳阶段而异。定量 HMO 分析的效率和选择性的改进对于进一步扩展我们对 HMO 变异对健康早期生命发展影响的理解至关重要。因此，我们在这里应用了一种有针对性、高选择性和半定量的 LC-ESI-MS ²通过分析在产后 6 周和 16 周收集的 2 × 30 成熟人乳样品的方法。分析方法涵盖了最丰富的 HMO，直至六糖，并且首次还指定了血型 A 和 B 四糖。采用主成分分析 (PCA) 并允许将人乳样品自动分组和分配到与母体分泌 (Se) 和路易斯 (Le) 基因型相关的四个人乳组。我们发现这四个 HM 组之间的 HMO 多样性差异很大。变异是由 HMO 依赖或独立于母体遗传 Se 和 Le 状态所驱动的。我们在 Se 和 Le 阳性 HM 组 I 中发现了一个额外的 HM 亚组的初步证据。此外，