Brown fat was found in adults
Good fat warms the neck thinPyotr Smirnov, "Newspaper.
Ru»
Scientists have finally been able to find the elusive brown fat in adults - a "good option" of adipose tissue, whose cells, instead of storing energy, burn nutrients in large quantities. Activated brown fat can protect mice and rats from both obesity and diabetes. Of the people in this regard, the elderly, overweight and hypertensive are the least lucky.
It would seem that all anatomical discoveries were made in the distant past, when dissecting corpses was more of an art, rather than routine preparation for regular classes with students. But modern physiologists with the help of X-ray, magnetic resonance and positron emission tomography prove the opposite: over the past 20 years they have managed to study the features of our vessels, bones and even the distribution of adipose tissue in the body.
The latter became the subject of close attention of Ronald Kahn from the Joslin Center for the Study of Diabetes: after examining in detail several thousand images taken over the past three years, scientists were able to say with confidence: "good" brown fat in adults is located mainly in the neck and shoulder blades and behaves quite actively.
The figure shows the spread and activity of brown adipose tissue according to positron emission and computed X-ray tomography. The black areas on the left image in the area highlighted by the red line are islands of brown adipose tissue. They are in the right picture – in the form of red-yellow areas. // C. Ronald Kahn, The New England Journal of Medicine 2009.
This is a powerful impetus to the development of numerous projects dedicated to the role of brown adipose tissue in the prevention of obesity and the following metabolic syndrome. These studies cannot be called unpromising: unlike the more common counterpart, which is deposited under the skin, in the omentums and capsules of internal organs, brown fat instead of storing energy burns it in large quantities, releasing heat.
This is especially noticeable in infants with still underdeveloped muscles responsible for thermoregulation in an adult. In the first year of life, it is brown fat that is responsible for warming the body. Gradually, this function passes to the muscles, and the "good" adipose tissue that has a lot in common with them disappears, remaining in the form of small, unstable islands, the presence of which was the exception rather than the rule.
Kahn and co-authors of a publication in the New England Journal of Medicine for the first time conducted a study of brown fat of this scale, which involved 1972 people. They did not dissect their wards, limiting themselves to analyzing images of individual areas and the whole body.
Significant deposits of brown fat were found in 3% of men and 7.5% of women. In the weaker sex, he not only met more often, but also behaved more actively.
Among the common differences is the constitution of the body of "happy owners of brown fat". As expected, the thin ones had six times more of it than the obese ones. Other factors associated with low brown fat content include high glucose levels, old age (over 64 years old) and the use of beta–blockers, traditionally used in the treatment of hypertension.
Perhaps Kahn would have been able to find more features if not for the retrospective nature of the study: scientists analyzed images taken for different indications for the diagnosis of various diseases. The scale of the sample, however, does not allow us to call these data one–sided - even despite the fact that most of the subjects were examined due to some kind of disease.
And the second publication of researchers from the Maastricht University Medical Center, based on the analysis of data on 24 healthy volunteers, partially confirms Kahn's conclusions, but differs from her in numbers – the activity of brown adipose tissue with a slight cooling was detected in 23 out of 24 people. 96% is much more than the mentioned 3% and 7.5%. Perhaps this is due to the age and criteria for the selection of participants and the "significance" of the islands of tissue encountered.
As for the causal relationship between the designated features and the amount of brown fat, there is still work to be done on the myths: it is not yet possible to say exactly what is primary and what is secondary.
On the one hand, the constitution of the body and diet can affect the deposits of brown fat, on the other – a large amount of the latter can be the cause of a slim figure and normal blood glucose levels. A third option is also possible: both the constitution and the amount of brown fat depend on an unknown third factor.
Logic and medical education incline scientists to the second option, especially since earlier the same research team showed how brown cells embedded between muscle fibers protect against obesity and resulting metabolic disorders.
The direction of further research is quite understandable, and socially justified: if scientists manage to find a way to selectively stimulate the development of brown adipose tissue, then there will simply be no end from obese customers: all the extra calories will instantly turn into heat. In rodents, a similar effect has already been reproduced even without the involvement of gene therapy.
Portal "Eternal youth" www.vechnayamolodost.ru10.04.2009