The secret relationship between belly fat and heart disease

Until now everyone knows that overweight people are at risk of heart disease, stroke and some problems arise from very high arterial obstruction. And those who have excessive weight in the waist with big beer belly or " apple " belly are the most at risk.

Although it has a great influence on human health, scientists still have not explained the relationship between heart disease and abdominal obesity. There is now a new study done on mice that provides the first evidence to explain the existence of this relationship, while providing the first knowledge to prevent it.

The University of Michigan Cardiovascular Group team of scientists has demonstrated the existence of a relationship between redness around cells accumulating abdominal fat and arteriosclerosis causing atherosclerosis. They also said that diabetes medicine may be used to limit this swelling, and prevent future artery damage.

Although scientists also warn that it is too early to apply to abdominal obesity patients, they hope further studies on humans and animals will reveal many things: this dangerous relationship occurs How it is, why it is, how to reverse it, and how to diagnose it from an early stage through a blood test.

Until then, the most useful advice for people who are overweight to reduce the risk of heart disease or stroke is still: reducing excess weight in the abdomen, losing excess weight throughout the body by applying a diet. Balance, ensure along with regular workouts.

The research leader is a doctor and a cardiologist - Daniel Eitzman, a scientist and associate professor of cardiology at VA Ann Arbor Healthcare System.

Part of the research results happened very casually. He and his colleagues are working on a defective mouse that regulates leptin (a hormone produced by high-fat cells that plays an important role in causing cravings, metabolism as well as birth). product) . In an effort to force obese mice to produce leptin, the team developed the technique of transplanting a group of fat-rich cells from normal mice that resemble leptin-deficient mice.

Normal mice (left) and obese mice with leptin-producing genes (right) helped the University of Michigan research team detect redness in the peri-abdominal fat area associated with atherosclerosis.(Photo: Image courtesy of University of Michigan Health System).

And the results surprised them, Eitzman said: 'Instead of producing leptin and preventing obesity, the cells that were transplanted should have attracted macrophage immune cells. Because these mice are genetically identical except for leptin-producing genes, this phenomenon should not have occurred. But the cells were red and it was repeated. '

Redness occurs around high-fat cells or adipocyte cells . Subsequent experiments demonstrated that the phenomenon is governed by factors that control redness occurring in the area of ​​natural fat accumulation in obese mice, namely a type of chemokine called MCP. -first. But because fat is transplanted, redness is directly related to fat, not because of overeating or metabolic disorders caused by excessive eating and obesity.

Along with this finding, scientists have been investigating what caused redness, and what effect it has. The team consisted of Miina Öhman - postdoctoral, doctoral and doctorate in philosophy, Professor UM Daniel Lawrence - a doctor of philosophy, and members of Eitzman and Lawrence's teams.

They are particularly interested in whether there is a link between redness and atherosclerosis - a name that indicates the process of blood vessels becoming stiff, narrow and wrinkled by plaque. show blood clots.

This phenomenon occurs throughout the blood vessels in the body causing heart attacks and strokes. Scientists and physicians have realized the cause is due to redness - this is an abnormal immune system response to tissues in the body. Immune cells and molecules may have caused this damage.

Because normal mice do not suffer from atherosclerosis, the team must switch to a special strain that is at high risk of arteriosclerosis and high cholesterol. The mice called ApoE-negative were divided into three groups: two high-fat cell transplants from normal mice, and one that was not transplanted but underwent a surgery to transplant the fat to the animals. other mouse.

Some fat ApoE-negative mice received fat from the abdomen surrounding some key organs, while others received fat from the skin under the body. Mice that received abdominal fat soon developed atherosclerosis, which was similar to the redness of mice leptin deficient. Meanwhile, those who received subcutaneous fat did not have atherosclerosis even though they were also red. And the fake surgery mice did not experience redness or atherosclerosis .

Eitzman, who said blood vessels far from the transplanted fat site had atherosclerosis, said: 'There seems to be an interaction between macrophage immune cells that causes swelling in the abdominal fat area. and atherosclerosis process'.

Finally, the team restricted the swelling and atherosclerosis caused by pioglitazone treatment - this is one of the thiazolidinedione (TZD) drugs commonly used to treat diabetes . TZD works with metabolic processes, so it is very effective in treating diabetes. They are also found to be effective at treating swelling.

In fact, this drug has just reduced the density of macrophages and MCP-1, while limiting atherosclerosis in mice with abdominal fat transplants; but it doesn't work in other mice.

Currently, scientists have proved the connection between abdominal fat, swelling and arteriosclerosis phenomenon. At the same time they discovered a potential method to reverse this phenomenon. The group is still exploring other aspects of the problem.

They are looking for factors that cause macrophage cells to enter the fat region and cause swelling. Blood cell-producing molecules can be used as a means of recognizing the initial warning signs of atherosclerosis. Scientists are also studying other pharmaceutical groups to find out if they have any positive effects, since TZD affects many organ systems in the body and causes some side effects.

The study was published online in Circulation on January 22, 2008 and will be published in February.

Joining the research group with Eitzman, O'man and Lawrence, Dr. Yuechen Shen, Chinyere Obimba, a University of Michigan alumni currently studying at Harvard Medical School, Andrew P. Wright, UM alumni and now Michigan medical school student, and Mark Warnock. The study was funded by the National Heart, Lung, and Blood Institute.