A new study reported in Nature Communications has shown how the body might use fat as fuel in the battle against a Salmonella infection. According to the Centers for Disease Control and Prevention, Salmonella bacteria cause an estimated 1.35 million infections every year in the United States alone. The symptoms include vomiting, abdominal pain, or fever, and may lead to sepsis. Although most of the time, people recover within about a week on their own, the infection leads to the hospitalization of about 26,500 people and the deaths of 420 Americans every year.
The bone marrow is home to hematopoietic stem cells (HSCs), which generate blood cells, including some that fight infection. A bacterial infection is known to stimulate activity in the HSCs.
In this study, the researchers found that when a Salmonella infection occurs, HSCs begin to take up free fatty acids. Those fatty acids are released by fat cells, or adipocytes, which are stimulated by signals from the bone marrow, After being powered by the fatty acids, the HSCs are free to produce plenty of white blood cells that can go fight the bacterial infection. The study also indicated that a molecule called CD36 was necessary for stem cells in there bone marrow to take up the free fatty acids.
The study authors are hopeful that this work will improve treatment options for people who are dealing with bacterial infections, particularly as more pathogenic bacteria develop resistance to common antibiotics. It may be possible to use a strategy based on this data to bolster the immune response to a bacterial infection.
"Our results provide insight into how the blood and immune system is able to respond to infection. Fighting infection takes a lot of energy and fat stores are huge energy deposits, which provide the fuel for the blood stem cells to power up the immune response," said co-corresponding study author Dr. Stuart Rushworth of the University of East Anglia's Norwich Medical School.
"Working out the mechanism through which this fuel boost works gives us new ideas on how to strengthen the bodies fight against infection in the future," added Rushworth.