Sepsis is caused by immune cells (blue) overreacting to an infection and damaging the body. Image credit: Courtesy of NIAID NIH BIOART (CC0)
Newborn babies, especially those born prematurely, are highly vulnerable to infections. This can then lead to sepsis, a life-threatening condition where the immune system overreacts to an infection and damages organs. Immune cells are fueled by nutrients, especially glucose (sugar), when they help defend the body against dangerous microorganisms. Therefore, high blood glucose levels can heighten the risk that these infection responses become too powerful and harm the body. However, too little glucose can also result in low blood sugar levels which can cause brain damage. This represents a key challenge in neonatal care, especially for babies which cannot be fed by mouth and therefore require nutrients to be delivered directly to their bloodstream (parenteral nutrition). Infants also struggle to regulate blood sugar levels on their own, which affects their response to infection.
The liver plays a major role in both immune responses and in converting nutrients into energy forms that our body can use. Adjusting glucose intake may influence how the liver generates energy and, in turn, prevent premature babies from developing sepsis.
To address this question, Bæk, Muk et al. infused premature piglets with parenteral nutrition containing different levels of glucose, starting shortly after birth. The health of the animals was then monitored before and after being infected with a bacterium Staphylococcus epidermidis, a common causative agent of infection in very preterm infants. The experiments showed that pigs that received lower levels of glucose were more likely to survive the infection than those that were given higher doses.
Despite receiving less glucose, the pigs managed to maintain their blood sugar levels within a safe range. This is because their livers compensated by shifting to using other sources of energy instead, and by manufacturing their own glucose. Further experiments found that adjusting glucose intake only protected against sepsis if the change was made early during infection, before the individual developed symptoms.
These findings suggest that adjusting the levels of glucose given to premature babies in hospital could be a simple, clinically relevant strategy to prevent sepsis. Further research is needed to explore how the liver uses alternative sources of energy to manufacture glucose and, in turn, to maintain normal blood sugar levels in infants.
