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Only a high-fat meal is the perfect stage for heart disease



(from left) Julia E. Brittain, dr. Neal L. Weintraub, Tyler W. Benson, dr. Ryan A. Harris and dr. Ha Won Kim photo taken at the Vascular Biology Center Lab of the Medical College of Georgia. Credit: Phil Jones, Senior Photographer, Augusta University

A single high-fat fat and calorie milkshake that resembles a tantalizing restaurant experience can quickly turn our healthy red blood cells into tiny, spiky cells that cause chaos in our blood vessels and the perfect stage for doing so , scientists report.

Just four hours after consuming a milkshake with whole milk, thick whipped cream and ice cream, healthy young men also had blood vessels that could relax less and provoke an immune reaction similar to one caused by infection, the team from the Medical College Georgia scientists report in the Journal Laboratory Investigation .

While the dramatic, unhealthy shift in these healthy individuals was likely to be transient, scientists say that there is a definitive cumulative toll on this type of food, their study could help provide isolated reports of death and / or heart attack just after to explain the food of a super fat meal.

"We hope to see this as a public service to get people to think twice," says Dr Neal L. Weintraub, cardiologist, Georgia Research Alliance Herbert S. Kupperman Eminent scholar in cardiovascular medicine and deputy director of the MCG Vascular Biology Center

"The message from home is that your bo dy can handle this normally if you do not repeat it at the next meal and the next and next," Dr. Julia E. Brittain, vascular biologist at the MCG Vascular Biology Center and corresponding author of the study. [1

9659005] As a practicing cardiologist, Weintraub, also a correspondent author, has patients with cardiovascular disease who continue to eat high-fat foods and in any case think twice: "Is this food worth your life?"

While none of the scientists recommend going beyond calories and sugars, the healthy men in the study who instead consumed a meal with the same number of calories but no fat – three large bowls of sugar-coated flakes with non-fat milk experience the same harmful changes to blood, red blood cells and blood vessels.

"They look at what a high-fat meal does to the health of blood vessels," says Dr. Ryan A. Harris, clinical exercise and vascular physiologist at MCG Georgia Prevention Institute and st udy co-author.

Her study of 10 young men was the first to specifically look at red blood cells, the most abundant cell in our blood. Red cells are best known for transporting oxygen and are incredibly flexible, allowing them to flow through blood vessels essentially unnoticed, says Brittain. But with a single high-fat meal, they essentially grow spikes and spew poison.

"They changed size, they changed shape, they got smaller," Harris says of the rapid changes in the shape and function of red blood cells.

There was evidence of myeloperoxidase or MPO, both in the cells and in the blood, an enzyme expressed by a type of white blood cell that is associated with stiff blood vessels, oxidative stress, and heart at high levels in the blood. Attack on humans ,

MPO is associated with a disturbed ability of blood vessels to expand, even an oxidation of HDL cholesterol, which converts this normally cardioprotective cholesterol into a contributor to cardiovascular disease. If it is taken up by a diseased artery, it may even help destabilize plaque formation, which can lead to a stroke or heart attack.

"Myeloperoxidase levels in the blood are directly involved in a heart attack," notes Weintraub. "This is a really powerful finding."

Using flow cytometry to study red blood cells, they found an increase in reactive oxygen species, a natural by-product of oxygen utilization that is destructive at high concentrations. An effect of their elevated levels permanently alters the function of proteins, including those that help the red blood cells maintain their normal negative charge.

MPO also influences the cytoskeleton, the physical infrastructure of normally bulging red cells, giving them "function and flex," says Tyler W. Benson, a graduate student at the Augusta University Graduate School and first author of the thesis. [19659005] "Again, your red blood cells are usually beautiful and smooth and beautiful, and the cells, after eating a high-fat meal, you should apply those spikes to them," says Brittain. "Like giant chunks of ice into a river, these physical changes affect the blood

Poor changes occur rapidly in these cells, which are "extremely sensitive" to their environment, says Brittain

Changes in white blood cells, called monocytes, that have themselves become fat to the excess fat Their earlier studies have shown that these so-called foamy monocytes promote inflammation and become athero show sclerotic plaques. Monocytes typically circulate and look for red blood cells that need to be eliminated because they are old and / or sick.

The fluid part of the blood, called the plasma, also looked different. When turning and separating various components of the blood to get to the red blood cells, they usually get a clear yellowish plasma above, says Benson. But after a single, high-fat load, the liquid part of the blood was already thick, out-of-round and filled with lipids.

Her blood also contained the expected high levels of fat and cholesterol.

At least in mice studies and in some of Brittain's other human studies, which also quickly resolve unhealthy changes by about eight hours, unless the greasy festivities continue. The researchers found that they only tested their participants after four hours, which roughly corresponds to the duration of the digestion.

Studies to measure longer-term effects on humans would be problematic, especially because healthy young people do not want to undergo the risk, Weintraub notes.

However, the MCG team has also shown that mice who are continually fed a high-fat diet experience lasting changes to their red blood cells and blood similar to those experienced temporarily by the young men. The changes include triggering a significant immune response that can contribute to vascular disease.

Further studies are needed to determine if changes in the shape of red blood cells affect vascular health, the researchers write. However, they suspect that the remodeled red cells themselves may be suitable for elimination by monocytes. In mice chronically fed a high-fat diet, they have seen red blood cells actively being consumed by macrophages, immune cells that eat cell debris, and resultant inflammation.

Weintraub says primary prevention is the wisest course for a healthy cardiovascular system to eat healthy, exercise regularly and keep track of vitamins like cholesterol and blood pressure. Even patients with a high genetic risk for cardiovascular disease can dramatically reduce this risk with these positive changes, he says.

Harris & # 39; s research team has conducted studies demonstrating that a single aerobic exercise session of young healthy people can counteract this unhealthy after discharge by four hours and the associated reduction in the ability to dilate blood vessels.

Participants in the new study were 10 physically active men with good medical history who did not take any prescription drugs and had good cholesterol and lipid levels

The researchers performed two thorough cardiovascular disease risk assessments at least seven days apart. Participants were encouraged to avoid caffeine and strenuous physical activity for 24 hours prior to each test and vitamin supplements for 72 hours. When they went to the doctor to get blood, they were also asked to fast overnight.

Half of the men got the milkshakes, which contained about 80 grams of fat and 1,000 calories. The cereal flour also contained about 1,000 calories, but very little fat. Meals were individually tailored to make sure everyone had the same amount of fat relative to their body weight, says Harris.

Since estrogen is considered cardioprotective in non-obese premenopausal women, the researchers chose to limit the study to men.

Blood cells, probably best known for transporting oxygen, are the most common cell type circulating in our blood. "They have 25 billion red blood cells and they affect every other cell in your body," says Brittain. They also carry the energy molecule ATP and Nitric Oxide, which helps to relax blood vessels, as well as cholesterol.

A healthy red blood cell has a negative charge that keeps it away from other cells and moves more towards the outer edge of blood vessels. In the arterial system, they move quickly, says Brittain.

The cells last about 120 days, but like many of us they become less efficient as we grow older, when they consume their energy or ATP storage, says Benson [19659005] The American Heart Association recommends that healthy adults stop fat intake Limit 20 to 35 percent of your daily calorie intake. The research was funded by the National Institutes of Health.


Further information:
New insights into why patients have a higher risk of having a heart attack in the morning

Provided by:
Medical University of Georgia at Augusta University


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