Scientists may have found a way that obesity directly damages the arteries and contributes to heart disease – a discovery that they say may eventually lead to new treatments.
British researchers found that in obese patients who are overweight, body fat surrounding the arteries tends to secrete large amounts of a protein called WNT5A. The protein, in turn, appears to have "toxic" effects in the blood vessels.
The results, published in September 18 of Science Translational Medicine are an early step.
But they suggest that WNT5A is a good target for new drugs aimed at treating or preventing heart disease, according to leading researcher Dr. Charalambos Antoniades.
"If we develop a treatment to" turn off "production of WNT5A from fat cells or block its effects on the wall [blood vessel]we might be able to" neutralize "obesity and prevent heart attacks and strokes," said Antoniades, a professor of cardiovascular medicine at the University of Oxford.
Many studies have shown that obese people have a higher risk of developing heart disease compared to thinner people. The American College of Cardiology (ACC) says it's partly due to "indirect" reasons: Obesity promotes conditions that can lead to heart problems – such as type 2 diabetes, high blood pressure and sleep apnea.
The new results, Antoniades said, highlight how obesity directly damages blood vessels.
For the study, he and his colleagues analyzed blood and tissue samples from approximately 1,000 heart disease patients who had undergone heart surgery. Overall, they found that obese patients had much higher levels of WNT5A in their blood.
The protein was specifically released in large amounts from fat around the blood vessels, Antoniades said.
In addition, patients with higher WNT5A levels tended to show faster development of "plaque" buildup in their arteries over the next three to five years. Plaques are deposits of fat, calcium and other substances that clog the arteries and can trigger a heart attack or stroke.
These findings alone do not point to WNT5A as a culprit for causing heart disease. But researchers found more direct evidence in the lab, according to Antoniades. It turns out that when blood vessel cells are exposed to the protein, they secrete more "toxic products" and enter a state that promotes plaque buildup.
Two American cardiologists reviewed the results of the study.
"This protein is not only significantly elevated in obese patients but also exerts blood vessel damage," Dr. Benjamin Hirsh, Head of Preventive Cardiology at Northwell Health Sandra Atlas Bass Heart Hospital in Manhasset, NY
Hirsh said WNT5A "pathway" is probably just one way in which obesity damages blood vessels. He called the results an "important step forward in improving our understanding of the specific mechanisms for which obesity is harmful."
Dr. Salim Virani is a cardiologist at the Michael E. DeBakey VA Medical Center in Houston and head of the ACC's Prevention Department and Leadership Council.
Virani agreed that it is important to understand the mechanisms that link obesity and heart disease, as it can lead to new, more targeted treatments. That said, no medicine will replace a healthy lifestyle, he stressed.
"Diet and exercise will always come first," Virani said.
Even a modest weight loss can benefit heart health, he pointed out. In addition, Virani added, obesity is also related to increased risks for other conditions, including some cancers. So aiming for a healthier weight will always be important.
And no matter how much weight you lose, Virani said, a healthier lifestyle that includes regular exercise can increase your physical and mental well-being.
"Being overweight and physically active is better than being overweight and sedentary," he said.
The "biggest challenge", according to Hirsh, is to convince people to make healthier choices and, in the first place, avoid obesity. But he handled it, he said, "will provide much greater benefits" than any medicine can provide.
Exercise also makes the "still overweight" healthier: the study
I. Akoumianakis et al., "Adipose tissue-derived WNT5A regulates vascular redox signaling in obesity via USP17 / RAC1-mediated activation of NADPH oxidases," Science Translational Medicine (2019). stm.sciencemag.org/lookup/doi/ … scitranslmed.aav5055
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Scientists discover new way that fat damages your arteries (2019, September 19)
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