Root canals, which treat endodontic infections, are one of the most common dental procedures. Yet, up to 15% of root canals fail, and patients require retreatment, or tooth replacement. Susan Rittling is trying to understand why these infections are so difficult to treat and to ultimately help develop more effective treatment options.
Rittling specifically studies the role of a protein called osteopontin (OPN), which has multiple effects on the body’s response to injury and inflammation. Rittling and her colleagues have shown that mice that lack osteopontin have an exaggerated inflammatory response to endodontic infections resulting in greater bone loss. She is also studying the effect of molecules that interact with OPN, its integrin binding partners, in endodontic infections and the general host response to infections.
“By studying the role of OPN and associated integrins, I hope that ultimately we will develop a new therapy to treat endodontic and other bacterial infections,” said Rittling. “A treatment developed from the body’s own response to infection would be less invasive and a better alternative to costly dental surgeries, which often don’t work.”
OPN’s role in the body is clearly important and also has implications in cancer. Many tumor types, including breast cancers, express high levels of OPN and this expression is associated with worse tumor outcomes. The Rittling lab also studies the mechanism by which OPN regulates tumor growth. She has recently found that OPN, which is normally found at high levels in milk, paradoxically suppresses the growth of certain tumors when fed to tumor-bearing mice. It appears that the orally administered protein is acting to regulate blood vessel development in tumors. While the mechanism of this effect is complex, it seems that peptide fragments of the orally administered protein reach the circulatory system and affect the cells that form blood vessels. This exciting result may lead to a new line of therapy for cancer treatment, as well as a natural product, purified milk OPN, for cancer prevention.
Rice University, BA, 1978, Biochemistry
University of Vermont, PhD, 1983, Biochemistry