Why are women less likely to experience brain inflammation than men?
(HINT: It’s NOT estrogen.)
A new study published in the journal Diabetes seems to indicate why women appear less likely to experience brain inflammation than men, and it’s not simply due to hormones.
“When people think about protection [against brain inflammation] in women, their first thought is estrogen,” says study author Dr. Alexis Stranahan, who works as a neuroscientist at the Medical College of Georgia at Augusta University. “But we need to get beyond the kind of simplistic idea that every sex difference involves hormone differences and hormone exposure. We need to really think more deeply about the underlying mechanisms for sex differences so that we can treat them and acknowledge the role that sex plays in different clinical outcomes.”
So, if estrogen isn’t what’s protecting women’s brains from brain inflammation, what is?
What the study found
For the research study, scientists fed male and female mice a high-fat diet to induce obesity. While the male mice had an increase in both inflammation in the adipose (fat) tissue and the brain, the female mice were less susceptible to the pro-inflammatory effects of the diet. More specifically, the researchers found:
• The male mice showed greater susceptibility to obesity-related metabolic and cardiovascular comorbidities
• As with humans, the male mice tended to store a greater amount of fat as visceral fat around the abdomen, while the females stored their excess energy in fat deposits under the skin (“subcutaneous fat”).
It’s worth noting that although the female mice showed a “superior ability” to regulate glucose metabolism at 24 weeks, there was no difference from the male mice in this ability at 48 weeks.
To determine if the subcutaneous fat was what might be protecting the female mice from the brain inflammation associated with obesity, the research team surgically removed it in both male and female mice. Then they fed the mice a high-fat diet. This time, the scientists saw an increase in inflammation in the females, similar to what they saw in the obese males. But even with the lipectomy, male mice fed a high-fat diet showed a higher level of inflammation.
Removing the subcutaneous fat showed that it had protected the female mice—but not male mice—from the inflammatory effects associated with obesity.
Wendy Burt-Thomas writes about the brain, mental health and parenting.
Check out the original research: