What are alarmins in breast milk

The intestinal mucosa interacts with the bacteria in the environment, thereby giving rise to a bacterial diversity that lasts a lifetime. This is how the intestinal immune system matures in the first place.

Researcher in the RESIST cluster found that alarmins, a class of proteins responsible for stimulating an immune response, are the star component of breast milk.

The researchers found higher quantities of two compounds—S100A8 and S100A9—in the poo of infants who were born after full-term and who were breastfed compared with preterm babies and babies who had been weaned.

After following the babies for 2.5 years, they reported: "High fecal levels of S100 proteins, from 30 days to 1 year of age, were associated with higher abundance of Actinobacteria and Bifidobacteriaceae, and lower abundance of Gammaproteobacteria—particularly opportunistic Enterobacteriaceae. A low level of S100 proteins in infants’ fecal samples associated with development of sepsis and obesity by age 2 years."

Hence these compounds were seen to protect children from infections as well as conditions like obesity.

Alarmins prevent intestinal colonisation and infections in infants by facilitating this process of adaptation. Research has also revealed that these peptides and proteins come from breast milk and also arise in the child's intestinal tract.

Another interesting thing found in the research is that infants born via planned C-section exhibit lower levels of alarmins than vaginally born infants, which means that the process of labour plays a role in the production of alarmins in the human body.

Additionally, premature infants are less capable of producing alarmins themselves than full-term infants, which makes them more prone to suffering from chronic inflammatory diseases. However, providing the infant supplements of this protein could prevent a range of long-term conditions linked to intestinal colonization disorders.

The lead authors of this research, Maike Willers of the MHH (Medizinische Hochschule Hannover) and Dr Thomas Ulas of the University of Bonn are now building upon their findings. The RESIST researchers are planning further preclinical work, as well as clinical study at a later stage.