MedicalResearch.com Interview with:
Esther Bullitt, Ph.D.
Dept. of Physiology & Biophysics
Boston University School of Medicine
Boston, MA 02118-2526
MedicalResearch.com: What is the background for this study?
Response: We know that saliva has properties that allow us to swallow easily, and to help prevent gum disease and infections in the mouth. But is that really the only use for the 1-2 liters (1-2 quarts) of saliva we produce every day? We decided to test whether a component of saliva, Histatin-5, can help prevent diarrheal disease (Traveler’s Diarrhea by Enterotoxigenic Escherichia coli (ETEC)) that is caused by bacteria commonly found in contaminated food and water.
ETEC are bacteria that have hundreds of thin hair-like fibers on their surface, called pili. These bacteria bind specifically to the surface of the gut using these pili, and the bacteria need to stay bound long enough to initiate disease. Studies by Mike Levine’s group in the 1970’s showed that pili are necessary for enterotoxigenic Escherichia coli (ETEC) to cause disease. No adhesion, no disease.
One aid to remaining bound is the unwinding and rewinding of the pili. These helical fibers can unwind up to 8 times their original length, acting as shock absorbers during fluid flow.
MedicalResearch.com: What are the main findings?
Response: After adding the saliva peptide Histatin-5 to ETEC bacteria, binding of the bacteria to organoids grown from a section cut out of a person’s gut small intestine is significantly reduced. We also see, using an electron microscope, that the pili become more rigid in the presence of the saliva peptide. Without the ability of pili to unwind and rewind, bacteria may still bind briefly in the gut, but without their natural shock absorbers (pili) they cannot stay bound. When bacteria are washed away, they cannot cause disease.
MedicalResearch.com: What should readers take away from your report?
Response: Saliva has a much bigger role in preventing disease than has been known – the saliva peptide Histatin-5 reduces binding to gut tissue by bacteria that cause Traveler’s Diarrhea. Without adhesion there is no disease, so we have a new path forward for therapeutics to help prevent getting sick from eating contaminated food.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: Our group has investigated one component from saliva (Histatin-5), against one type of bacteria that causes disease (ETEC that cause Traveler’s Diarrhea). Saliva has many other components that might work against other disease-causing bacteria, and we hope that there will be future research to test these possibilities.
MedicalResearch.com: Is there anything else you would like to add?
Response: We already produce and swallow Histatin-5 every day in our saliva. Therefore, the potential for using Histatin-5 to develop a non-toxic therapeutic is high. We anticipate that added Histatin-5 can increase the number of bacteria that can’t bind, after eating contaminated food. No adhesion, no disease!
This work was funded primarily by the NIH, Boston University School of Medicine, and Washington University; no authors have any conflicts of interest.
A Role for Salivary Peptides in the Innate Defense Against Enterotoxigenic Escherichia coli
Jeffrey W Brown Arwa Badahdah Micah Iticovici Tim J VickersDavid M Alvarado Eva J Helmerhorst Frank G Oppenheim Jason C MillsMatthew A Ciorba James M Fleckenstein Esther Bullitt
The Journal of Infectious Diseases, jiy032, https://doi.org/10.1093/infdis/jiy032
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