Analysis of gene expression from human breastmilk cells: a comparison between low and high producers, and the influence of anxiety and depression on milk production, gene expression and bacterial production.

Breastmilk is considered the gold standard of infant nutrition. Many mothers have difficulty with breastfeeding and over 50% of women stop due to perceived low production, which can exacerbate anxiety and depression. Our study set out to compare gene expression and bacterial populations in 8 total samples of low (4) and high (4) milk producers. Methods: All subjected were at mature lactation, administered GAD and PHQ-9 questionnaires and milk RNA was extracted. Total RNA was isolated and examined using the Agilent 4200 TapeStation System. Libraries for RNA-Seq were constructed to generate strand-specific RNA-seq libraries. Results: Low-producers were all found to have higher depression and anxiety scores on the PHQ-9 and GAD respectively, compared to high-producers. We did not find significant differences between gene expression between low and high milk producers. We did not find a significant difference in the amount of bacterial between low and high milk producers. Only 5 of 8 samples contained a significant number of human cells and further deconvolution of the data revealed a variety of hematopoietic stem cells, non-hematopoietic stem cells and white blood cells across all 5 samples. Conclusion: Even though low milk producers showed higher anxiety and depression scores, the myriad of cells, and the diversity of bacteria present (proteobacteria, Actinobacteria and firmicutes phylla) in milk samples of all subjected strongly reinforces that infants will receive numerous benefeits even from a small amount of milk.