Did you know that after breast feeding, the cells that help to produce the mother’s milk start a process of auto-cannibalism? The “big clean” is carried out by the protein Rac1 also known as the “Pac-Man protein”. We will explain further.
When a woman has just given birth, her breasts are filled with milk 24 hours per day. On the contrary, when she stops breastfeeding her breasts return to normal. In September 2016, the journal Developmental Cell revealed a study led by Nasreen Akhtar and his team from the University of Sheffield, which described how a woman’s breast returned to normal after the breastfeeding stage.
The research, which helps us to better understand breast cancer, has highlighted a rather incredible process. In fact, the cells which contribute to producing the mother’s milk transforms into “a cleaner” after the period of breastfeeding so that it can carry out a big clean up so that the breasts can return to normal. This auto-cannibalism of the breasts is carried out by the protein Rac1, nicknamed the Pac-Man protein in reference to the famous video game where the main character is incredible greedy out of necessity.
When a woman is not pregnant or breastfeeding, her breasts are made up of a network of channels surrounded by fat. However, during pregnancy, a multitude of hormonal signals create an increasing number of epithelial cells (found in the channel walls), while ephemeral cells form where milk will be stored. This is why breasts often double in size during pregnancy. When the breastfeeding phase ends, the lady’s breasts return to their normal size. The structures mentioned above self-destruct, which generates a significant amount of debris.
This kind of “big clean” is usually carried out by the immune system, via the phagocytion process. However, this process is synonymous with inflammation, pain and tissue damage, a host of events that do not appear after breastfeeding. In fact, it is the Rac1 protein, which is involved both in the context of phagocytion and in milk production, which carries out this process.
However after breastfeeding, the Rac1 protein acts as a regulator, calling epithelial cells to work alongside them, without using many white blood cells which are usually very active during inflammation.
This study will help us better understand the development process that leads to breast cancer, while this self-cannibalism post breastfeeding could reduce the risks.