From the article:
In a Y-shaped maze with three arms to explore, uninfected mice tended to explore all three arms, while mice with UTIs [urinary tract infection] kept returning to the same one, suggesting a lapse in short-term memory, another feature of delirium.
The investigators also observed structural changes in the brains of mice with UTIs.
In a previous study led by Lahiri, published in February in the American Journal of Respiratory Cell and Molecular Biology, investigators found a connection between ventilator-induced lung injury and delirium. Lahiri and colleagues theorized that in both cases this was because of the reaction of IL-6, which helps regulate immune response, to the lung injury or the UTI.
“Occasionally, when the response of IL-6 is excessive, our research indicates that there can be brain injury,” Lahiri said. “IL-6 induces changes within the neurons that our studies connected with delirium-like behavior. This is the first time this type of structural and functional change has been demonstrated. We’ve now shown two distinct models of this connection, one non-infectious and one infectious.”
In the current study, when investigators treated some of the infected mice with antibodies that blocked the effects of IL-6, the delirium-like behavior of those animals resolved. “Treatment with anti-IL-6 antibody in the UTI group normalized all the brain changes, both structural and functional,” Lahiri said. “A wealth of studies have shown a link between IL-6 and delirium, but only this study and our previous study have shown that IL-6 may play a direct pathological role in delirium.”
If symptoms are treated early, he added, full recovery is possible, and the next step is to design clinical trials with anti-IL-6 antibodies as a treatment for patients with UTI-induced delirium.