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Adipose tissue helps arteries with stress relaxation
While deposits within arteries increase the risk of a heart attack, fat that builds up around the arteries can play an important role in keeping these blood vessels healthy, according to a recent study.
Researchers at Michigan State University are providing new evidence that so-called perivascular fat helps the arteries to relax. This finding could affect the way plaque buildup, hypertension, or atherosclerosis is diagnosed. The results were presented in the renowned scientific reports.
What is perivascular adipose tissue?
Perivascular fat (PVAT) is adipose tissue that surrounds arteries or blood vessels. This fat is different from other adipose tissue. It is unclear whether it is harmful to health or benefits. While previous studies in mice suspected a harmful effect, a current study now shows that PVAT contributes to stress relaxation of arteries.
The interplay between pressure and relaxation
Blood vessels are under constant pressure. Much like the bladder, they occasionally need to expand to hold more fluid while maintaining tension to prevent the fluid from running away in an uncontrolled manner. PVAT seems to play a crucial role in this interplay.
Relaxation through fat deposits
"In our study, perivascular fat reduced the tension that the blood vessels experience during stretching," reports Stephanie Watts, professor of pharmacology and toxicology. This is good for the vessels in that it reduces energy expenditure. According to the study, the arteries are less stressed by PVAT.
Does the structure of blood vessels need to be redefined?
According to Watts, this task of fat has so far been largely ignored in research. The current findings can now contribute to the need to re-examine blood vessels. Because blood vessels are currently only divided into three parts: the innermost layer (Tunica Intima), the middle layer (Tunica Media) and the outermost layer (Tunica Adventitia).
The Watts team now wants the PVAT layer to be recognized as the fourth layer of blood vessels. This layer should be called "tunica adiposa".
The shift was ignored for decades
“We ignored this layer for years - it was thrown away in the laboratory; it was not shown in the clinic, ”Watts emphasizes. The findings now indicate that the fat layer could be an integral part of our blood vessels. Watts points out that this basis could have massive consequences in research: "Our findings redefine the functional blood vessels and are part of what can be disrupted in diseases that affect us, such as high blood pressure."
More attention to PVAT
"We need to pay more attention to this shift because it does far more than we originally thought," Watts says. Previous studies have shown that PVAT secretes both substances that relax the blood vessels and substances that can cause contraction of the vessels.
A newly discovered general phenomenon?
The Watts team tested the function of PVAT in rats. The researchers found that the thoracic aorta shows greater stress relaxation when the PVAT is intact than when it is not. Watts and her colleagues also tested other arteries and were able to duplicate the same answer. "So this tells us that it is not just a one-off appearance," sums up the professor. It could be a general phenomenon. (vb)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Graduate editor (FH) Volker Blasek
- Stephanie W. Watts, Emma D. Flood, Hannah Garver, et al .: A New Function for Perivascular Adipose Tissue (PVAT): Assistance of Arterial Stress Relaxation; in: Scientific Reports, 2020, nature.com
- Michigan State University: The Fat around your Arteries may actuakky keeo them healthy (published: February 20th, 2020), msutoday.msu.edu