Solitude may be fatal for stroke-hit individuals

Washington, March 26: A study by Ohio University researchers suggests that solitude can elevate death risk in the event of a stroke, by increasing inflammation in the brain.

Study lead Kate Karelina, along with her research colleagues at Ohio State University, conducted experiments on male mice and figured that mice with a female partner fared better after a stroke, living almost up to seven days, whereas isolated mice responded quite poorly, with just 40 percent of stroke-hit mice surviving for seven days.

"Under nearly every measure, it seems there was something about living together that protected the mice by reducing the damaging inflammatory response," Karelina, a doctoral student in neuroscience at the University, said.

The team of researchers induced experimental strokes in male mice, wherein some of the mice were already living with a female partner while others were kept isolated throughout the study. Another controlled group of mice were operated upon for brain surgeries, though no stroke was induced.

Brain tissues of these mice were studied 12 hours, one day, three days and seven days after the stroke to assess the neural damage. It was found that tissue damage among mice living with partners was much slower than the isolated group, making them survive for a longer period after the stroke.

Courtney DeVries, associate professor of psychology and neuroscience at Ohio State University, said, "We confirmed that social isolation contributes to the extent of neuronal damage in the brain as early as 24 hours after the stroke. The number of neurons dying is significantly decreased in the pair-housed mice." DeVries is a member of the Institute of Behavioral Medicine Research at the University.

Rate of tissue damage was observed to be four times greater in the lonely set of mice compared to their partnered counterparts. Social mice had less amount of excess water in the brain, referred to as edema, as compared to the solitary mice.

"In clinical stroke, edema is a major concern because it can lead to additional neuronal damage, so it is significant that pair housing reduced edema," noted Karelina. The study will be published soon in the 'Proceedings of the National Academy of Sciences'.

Researchers believe that two genesdefine are responsible for the brain inflammation during stroke that damages the tissues. One is MAC-1 and the other is GFAP, glial fibrillary acidic protein. Both of these had diminishing signs of activity in the socially active mice.

Partnered mice exhibited good levels of a cytokine in the brain, known as interleukin-6 (IL-6), having an anti-inflammatory reaction in the brain which scales down the extent of damage in the event of stroke.