Thick polar bears with high cholesterol healthy

Iron bears lead a healthy life despite thick layers of fat and a lot of cholesterol in the blood

09/05/2014

Polar bears are all the more fitter for people who are anything but healthy: high cholesterol levels and thick layers of fat under the skin do not hurt polar bears in the least. The animals even need a lot of fat, as the lipid decomposition produces metabolic water, which they rely on because they rarely have access to fresh water in their habitat. A gene should be responsible for ensuring that high cholesterol levels in polar bears do not pose a health risk.

Removal of brown bears caused polar bears to adapt to high-fat foods
Polar bears have a very high cholesterol level and a five to ten centimeter thick layer of fat under the skin. While people with high blood lipids are at an increased risk for cardiovascular diseases such as atherosclerosis, high blood pressure, and heart attacks, which can result in death, polar bears may even be high in fat. The animals have a special genetic equipment, such as a research team around the biologist Rasmus Nielsen in the journal „Cell“ reported.

The researchers analyzed the genome of 79 polar bears from Greenland and ten brown bears from Canada, Alaska and Scandinavia and came to the conclusion that ice and brown bears went far later separate ways than experts have previously assumed. Accordingly, they separated only 343,000 to 479,000 years ago as estimated until 600,000 to five million years ago. After this split, it had come to a nutritional adjustment of the polar bears to a very high-fat diet, the researchers write. „The life of the polar bear is about fat, "said Eline Lorenzen of the University of California at Berkeley, co-author of the study, told the news agency „dpa“. „Polar bears live in the polar desert and have no access to fresh water most of the year. Therefore, they rely on metabolic water, which is a by-product of fat splitting. "Thus, fat does not only seem to be an energy source for the animals, but a vital part of their metabolism.

Gene ensures good tolerance of fat and cholesterol in polar bears
The researchers found in their investigations on significant differences in the genome of polar bears and brown bears. „We found that the genes of the polar bear lineage were more strongly selected than those of the brown bears“, it says in the journal. „Nine of the 16 highly selected genes were associated with cardiomyopathy and vascular disease.“ In particular, one gene appears to be responsible for the transport of cholesterol from the blood into the body's cells, reducing the risk of cardiovascular disease.„One of the genes that provides the most important evidence for selection, APOB, encodes the primary lipoprotein component of low-density lipoprotein (LDL); Functional mutations of APOB may explain why polar bears are capable of living with increased LDL levels in their lifetime, in people at high risk of developing heart disease“, the researchers write. (Ag)