This Happy Hormone Can Protect You From Gastrointestinal Infections, Study Reveals

Happy hormones can help reduce the ability of some intestinal pathogens to cause deadly infections, revealed a new study.

Serotonin- a chemical which plays a vital role in producing feelings of happiness and well-being in the brain can influence intestinal pathogens from causing infections.

The experts at the UT Southwestern found a new way to fight infections for which very few effective treatments exist currently.

Even though the major part of the research has centered on the effects of serotonin in the brain, the researchers explained that about 90% of the neurotransmitter is produced in the gastrointestinal (GI) tract.

In human beings, trillions of bacteria live in the GI tract. While most of them are beneficial, there are some pathogenic bacteria that can colonize the GI tract and lead to serious and potentially fatal infections.

Since gut bacteria are significantly affected by their environment, the researchers sought to find out whether the serotonin secreted in the gut might affect the virulence of pathogenic bacteria infecting the GI tract.

The Study:

The research team studied a species of bacteria- Escherichia coli 0157 that causes periodic outbreaks of deadly foodborne infection. They grew these pathogenic bacteria in Petri dishes and then exposed them to serotonin.

Gene expression tests revealed that exposure to serotonin hormone significantly reduced the expression of a group of genes used by these pathogenic bacteria to cause infections.

Further experiments using human cells revealed that bacteria could no longer cause infection-associated lesions on the cells when these bacteria were exposed to serotonin.

They also examined how serotonin affected virulence in living hosts. Using mice models, they studied how the hormone might influence the ability of a mouse gut bacterium called Citrobacter rodentium to infect and sicken their hosts.

The mice were genetically modified to over or underproduce serotonin in their GI tracts.

Key findings:

• Those that overproduced serotonin were less likely to become colonized by C.rodentium after being exposed to the bacterium
• Treating mice with fluoxetine/Prozac to increase serotonin levels prevented these mice from getting sick from the bacterium
• But the mice that underproduced serotonin got much sicker upon exposure to the bacterium and often died from an illness

In the future, the researchers plan to study the feasibility of manipulating serotonin levels as a way of fighting bacterial infections in the GI tract.

"Treating bacterial infections, especially in the gut, can be very difficult. If we could repurpose Prozac or other drugs in the same class, it could give us a new weapon to fight these challenging infections," study leader Vanessa Sperandio, Ph.D., a professor of microbiology and biochemistry at UT Southwestern Medical Center told MedicalXpress.