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zoom RSS 妊娠中の高脂肪食が胎児脳に肥満となる原因を作る

<<   作成日時 : 2008/11/20 20:33   >>

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 妊婦が高脂肪食をとると、胎児脳が変化し肥満を引きおこす。
 ロックフェラー大学チームのラットを使った実験で、高脂肪食を与えられた親から生まれると食欲を刺激する蛋白を生成する脳細胞が増加するという。
 前の研究で、血中トリグリセリドが脳内で食欲促進蛋白産生を刺激して、食欲を刺激するとわかっていた。
 最新の研究で、母親の食事からのトリグリセリドが胎児発育脳に同じ影響を及ぼし、その効果は終生続く。また、思春期も早く始まった。出生時に血中トリグリセリドが高く、成長してからの脳内の食欲促進蛋白orexigenic peptidesが高値だった。胎児脳の検索で食欲増進ペプチドを産生する脳細胞の増加が見られ、生涯にわたって続いていた。体内で高脂肪に曝されると、それに耐えられるように胎児脳がプログラムされると考えられる。
 しかし、実験でラットに与えられた食事は極めて不自然なものなので、結果をそのまま性急に人間に当てはめるわけにはいかない。
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Page last updated at 00:03 GMT, Monday, 17 November 2008
Obesity 'programmed before birth'
http://news.bbc.co.uk/2/hi/health/7721438.stm

画像Pregnant woman
Diet in pregnancy may have a lasting impact

Eating a high-fat diet in pregnancy may cause changes in the foetal brain that lead to over-eating and obesity early in life, research suggests.

Tests on rats showed those born to mothers fed a high-fat diet had many more brain cells specialised to produce appetite-stimulating proteins.

The Rockefeller University team say the finding may help explain why obesity rates have soared in recent years.

The study appears in the Journal of Neuroscience.

Previous research on adult animals had shown that when fats known as triglycerides circulate in the blood they stimulate the production of proteins in the brain known as orexigenic peptides, which in turn stimulate the appetite.

We are programming our children to be fat
Dr Sarah Leibowitz
Rockefeller University

The latest study suggests exposure to triglycerides from the mother's diet has the same effect on the developing foetal brain - and that the effect then lasts throughout the offspring's life.

The researchers compared the offspring of rats fed a high-fat diet for two weeks with those whose mothers ate a moderate amount of fat.

They found that the pups born to the high-fat diet mothers ate more, weighed more throughout life, and began puberty earlier than those born to mothers who ate a normal diet.

They also had higher levels of triglycerides in the blood at birth, and as adults, and a greater production of orexigenic peptides in their brains.

Brain cells

More detailed analysis showed that, even before the birth, the high-fat pups had a much larger number of brain cells that produce orexigenic peptides - and they kept them throughout their lives.


The time to start feeding your child a healthy diet is right at the beginning of pregnancy
Dr Ian Campbell
Weight Concern

Their mothers' high-fat diet appeared to stimulate production of the cells, and their subsequent migration to parts of the brain linked to obesity.

In contrast, rats whose mothers had a balanced diet had far fewer of these specialised cells, and they appeared much later after birth.

Lead researcher Dr Sarah Leibowitz said: "We believe the high levels of triglycerides that the foetuses are exposed to during pregnancy cause the growth of the neurons earlier and much more than is normal.

"This work provides the first evidence for a foetal program that links high levels of fats circulating in the mother's blood during pregnancy to the overeating and increased weight gain of offspring after weaning."

The researchers suggest that the foetal brain is programmed so that the offspring can survive on the same diet as their mother - and they believe a similar mechanism may be operating in humans.

Dr Leibowitz said: "We are programming our children to be fat."

Dr Ian Campbell, medical director of the charity Weight Concern, said it had already been known that a high-fat diet in pregnancy made a child prone to a preference for fatty foods - but it had not been clear why.

He said: "The message is clear. We are not just 'what we eat'; we are also to some extent 'what our mothers eat'.

"The time to start feeding your child a healthy diet is right at the beginning of pregnancy."

Professor Ian MacDonald, an expert in the biology of obesity at the University of Nottingham, said there was clear evidence that nutrition before and soon after birth had an on-going impact on the genes.

But he warned against extrapolating too readily from animal studies, particularly as the rats in the latest study were fed a very unnatural diet.

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The Journal of Neuroscience, November 12, 2008, 28(46):12107-12119; doi:10.1523/JNEUROSCI.2642-08.2008

Maternal High-Fat Diet and Fetal Programming: Increased Proliferation of Hypothalamic Peptide-Producing Neurons That Increase Risk for Overeating and Obesity

Guo-Qing Chang, Valeriya Gaysinskaya, Olga Karatayev, and Sarah F. Leibowitz

The Rockefeller University, New York, New York 10065

Correspondence should be addressed to Sarah F. Leibowitz, The Rockefeller University, 1230 York Avenue, New York, NY 10065. Email: leibow@rockefeller.edu

Recent studies in adult and weanling rats show that dietary fat, in close association with circulating lipids, can stimulate expression of hypothalamic peptides involved in controlling food intake and body weight. In the present study, we examined the possibility that a fat-rich diet during pregnancy alters the development of these peptide systems in utero, producing neuronal changes in the offspring that persist postnatally in the absence of the diet and have long-term consequences. The offspring of dams on a high-fat diet (HFD) versus balanced diet (BD), from embryonic day 6 to postnatal day 15 (P15), showed increased expression of orexigenic peptides, galanin, enkephalin, and dynorphin, in the paraventricular nucleus and orexin and melanin-concentrating hormone in the perifornical lateral hypothalamus. The increased density of these peptide-expressing neurons, evident in newborn offspring as well as P15 offspring cross-fostered at birth to dams on the BD, led us to examine events that might be occurring in utero. During gestation, the HFD stimulated the proliferation of neuroepithelial and neuronal precursor cells of the embryonic hypothalamic third ventricle. It also stimulated the proliferation and differentiation of neurons and their migration toward hypothalamic areas where ultimately a greater proportion of the new neurons expressed the orexigenic peptides. This increase in neurogenesis, closely associated with a marked increase in lipids in the blood, may have a role in producing the long-term behavioral and physiological changes observed in offspring after weaning, including an increase in food intake, preference for fat, hyperlipidemia, and higher body weight.

Key words: maternal high-fat diet; lipids; hypothalamus; orexigenic peptides; neurogenesis; food intake

Received June 10, 2008; revised Oct. 3, 2008; accepted Oct. 14, 2008.

Correspondence should be addressed to Sarah F. Leibowitz, The Rockefeller University, 1230 York Avenue, New York, NY 10065. Email: leibow@rockefeller.edu

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妊娠中の高脂肪食が胎児脳に肥満となる原因を作る 医師の一分/BIGLOBEウェブリブログ
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