Like people, mice sometimes show signs of general confusion and memory loss after surgery. Common major (noncardiac) procedures, such as orthopedic operations, can lead to postsurgical cognitive decline in some seven to 26 percent of patients. And though it's usually temporary, this mental fogginess has been linked to worse overall recovery and long-term cognitive problems.
This phenomenon has come to the attention of some researchers working in the field of immunology. Surgery, like acute infection, has been shown to spur the immune system's inflammatory response, producing a spike in cytokine levels (including that of interleukin-1 beta), which are involved in cellular communication. A surge of inflammation, as detected by increases in interleukin-1 beta, has also been linked to cognitive dysfunction of the ilk often seen after surgery. And a study published in Neurology also found that Alzheimer's patients with persistent inflammation had quadruple the memory loss over six months compare to those without signs of inflammation.
In hopes of dialing down passing postoperative dementia, researchers have been exploring the use of common cytokine inhibitors, such as those used to treat rheumatoid arthritis.
A new study found that giving mice a dose of anti-tumor necrosis factor (TNF) antibody before orthopedic surgery decreased the animals' dementia-like behaviors.
"This finding suggests a pivotal role for systemic inflammation in producing neuroinflammation and cognitive decline," the researchers noted in the new study, which was published online November 1 in Proceedings of the National Academy of Sciences.
The prophylactic could be as simple as a single pre-operative shot, and researchers hope to move into human clinical testing of this use for the drugs within a year.
Beyond this postsurgical forgetfulness, "cytokines are potential therapeutic targets in a wider range of diseases," Sir Marc Feldmann, of the Kennedy Institute of Rheumatology at Imperial College London and study collaborator, said in a prepared statement. Systemic inflammation has also been linked to depression and other neurological ills. "Moreover," Feldmann said, "effective therapeutics already are available, with a known safety profile and modest cost."
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