“We have shown that milk changes throughout lactation, even after years of milk production,” says lead author and former postdoc Brittany Goods, PhD ’17, assistant professor of engineering at Dartmouth.
The most abundant cells they found were lactocytes, which expressed many genes for proteins found in breast milk as well as transporters needed to secrete proteins, micronutrients, fats and other components. Over time, the researchers found that the proportion of lactocytes involved in milk production decreased, while the proportion involved in the structural support of the mammary gland increased. At the same time, genes involved in the response to the hormone prolactin became more active in milk-producing lactocytes but decreased in structural lactocytes. These changes may be related to the changing nutritional needs of infants as they grow.
The study “Paving the way for mapping and better understanding some of the pathways these cells use to accomplish the enormous amount of work they do,” Goods says.
“It not only gives us a way to understand lactation, but it also gives us a set of data and tools to be able to design better solutions to improve the quality of life of mothers.”