Study author: “My mind was blown. I made every single person in my lab come and look and I asked, ‘Tell me if I’m hallucinating…do you think this is real?'”
EAST LANSING, Mich. — Fat, when it’s located around an artery, may actually be a good thing, believe it or not. That’s the surprising conclusion of a recent Michigan State University study that focused on blood vessel health. If true, this discovery could conceivably change how medical professionals and researchers alike test for treatments related to plaque buildup in arteries (atherosclerosis).
Atherosclerosis is usually a precursor to a heart attack, which is among the leading causes of death in the United States.
This fat, referred to as perivascular adipose tissue (PVAT), helps arteries “stress relax,” or release muscular tension while under stress. Researchers compare this action to the bladder, which naturally expands as a person produces more urine.
“In our study, PVAT reduced the tension that blood vessels experience when stretched,” explains Stephanie Watts, MSU professor of pharmacology and toxicology in the College of Osteopathic Medicine, in a release. “And that’s a good thing, because the vessel then expends less energy. It’s not under as much stress.”
According to Watts, these findings are especially noteworthy because PVAT has really never been studied extensively by scientists as it was always assumed to primarily store lipids and nothing else. This study, in combination with other recent pieces of research, may prove to change how scientists see blood vessels in general.
Today, blood vessels are currently divided into three sections; the inner most layer (tunica intima), the middle layer (tunica media), and the outer layer (tunica adventitia). Watts believes PVAT should be officially recognized as a fourth layer.
“For years, we ignored this layer – in the lab it was thrown out; in the clinic it wasn’t imaged. But now we’re discovering it may be integral to our blood vessels,” Watts comments. “Our finding redefines what the functional blood vessels are and is part of what can be dysfunctional in diseases that afflict us, including hypertension. We need to pay attention to this layer of a blood vessel because it does far more than we originally thought.”
Previous studies had found PVAT helps maintain overall blood vessel functioning by secreting substances that help the vessels relax, as well as other substances that help the vessels contract. However, Watts and her team were more interested in determining if PVAT itself, not any substances it produces, influence blood vessel health. To that end, they tested PVAT’s ability to provide structural support to arteries via stress relaxation.
This was accomplished by testing the the thoracic aorta in a group of test rats. Surprisingly, the rats with PVAT had more stress relaxation.
“My mind was blown,” Watts says. “I made every single person in my lab come and look and I asked, ‘Tell me if I’m hallucinating…do you think this is real?’”
Just to be sure, researchers duplicated their test on other arteries and had the same results.
“So, this tells us, it’s not just a one off,” Watts concludes. “It’s not something you see only in this particular vessel or this particular species or this particular strain. But that maybe it’s a general phenomenon.”
The study is published in Scientific Reports.