Co-authors of the study are DMS professors Dr. Bruce Stanton of physiology, who heads the laboratory where Moreau-Marquis works, and Dr. George O'Toole of microbiology and immunology.
The research combines two results: "We were first to show iron is definitive for biofilms forming on live human airway cells. And the highest concentration of tobramycin that can reach CF lungs is below what we've shown to be barely enough to eradicate biofilms on airway cells," Moreau-Marquis said.
The team used two FDA-approved iron chelators, deferoxamine and deferasirox, that can remove excess iron from the system by binding to the metal in a process called chelation. To mimic the clinical environment, they stuck to the maximum possible tobramycin dose of 1,000 micrograms per milliliter, mixed with a chelator.
The combination had a dramatic effect: it disrupted the mass of established and highly resistant bacteria in human airway cells by 90 percent and it also prevented formation of damaging biofilms. In contrast, neither an iron chelator nor tobramycin alone had such success.
"We built on the idea that if more iron helps bacteria to grow, maybe taking iron away will help kill them," said O'Toole. "The concept is to reformulate one of these iron chelators to be inhaled with tobramycin, which is already inhalable, to treat the bacteria locally in the lungs."
Still, the team found evidence that a chelator can get into lungs from the bloodstream. Using a permeable support in the lab, they mimicked giving tobramycin to the lung side and a chelator to the blood side and showed tha
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