Variants of two genes in the inflammatory system appear to protect patients from a decline in mental function following heart surgery, according to Duke University Medical Center researchers.
The investigators selected known variations in 37 genes that previous studies had implicated in various impairments of cognitive and mental function. When they looked at heart surgery patients and correlated cognitive decline with the patient’s genetic makeup, they discovered that those with variants in genes for C-reactive protein and P-selectin were less likely to suffer cognitive decline.
C-reactive protein plays a role in the body’s initial response to injury. Studies have shown that high levels of the protein puts patients at higher risk for cardiovascular disease and stroke. P-selectin is helps recruit circulating white blood cells to the site of an injury.
For their analysis, the researchers gave 513 heart patients a battery of cognitive exams before heart surgery and then six weeks later. They found that patients with the variation of the C-reactive protein gene were 20.6% less likely to suffer mental decline and those with the P-selectin variant had a 15.2% risk reduction. The incidence of deficit in patients with both gene variants was 17% compared to 43% in patients who had neither variant.Furthermore, patients with the two gene variants had significantly lower levels of C-reactive protein in their bloodstream and lower P-selectin expression. The investigators say this factor may provide a biological basis for the protective effect they observed.
The results were reported online Tuesday, May 1, in the Journal of the American College of Cardiology.