Blocking a single brain enzyme helped short-circuit a key hunger signal in mice and made them eat less, lose weight and have better blood sugar control, U.S. researchers said on Tuesday.
While much more research lies ahead, they said the finding may lead to new treatments for obesity and diabetes in humans.
"We believe we have identified an important drug development target that could potentially turn into a metabolic triple play: appetite control, weight loss and blood sugar management," said Tony Means of Duke University Medical Center in Durham, North Carolina, whose study appears in the journal Cell Metabolism.
Dr. Means's team focused on the enzyme CaMKK2, which plays a role in appetite stimulation in mice and in humans. Found in a region of the brain known as the hypothalamus, it takes its orders from a hormone released in the gut known as ghrelin, which is released when the stomach is empty.
Ghrelin is already linked to appetite control.
In a separate brain imaging study in the same journal, researchers at the Neurological Institute at McGill University in Montreal showed that ghrelin not only makes people feel hungry, but it makes food look more appealing by activating pleasure signals in the brain.
Dr. Means's idea is to find a way to interrupt ghrelin's activity by toning down the CaMKK2 enzyme's response to the hunger signal.
His team found that mice genetically engineered to lack the enzyme CaMKK2 stayed slim regardless of whether they were on a low-fat or high-fat diet...
Sunday, September 26, 2010
Virus 'link' to childhood obesity
A virus which causes respiratory infections has been linked to childhood obesity, in a study that is likely to reignite a controversial debate.
Previous animal research has implicated common viruses in weight gain, but the evidence has been disputed.
The latest study, in Pediatrics, found that obese children with antibodies specific to a certain virus weighed 35lbs (15.8kg) more than those without.
Nothing has yet been proven on this theory, say UK experts.
Previous research has shown that chicken or mice injected with similar types of viruses showed a statistically significant weight gain...
Previous animal research has implicated common viruses in weight gain, but the evidence has been disputed.
The latest study, in Pediatrics, found that obese children with antibodies specific to a certain virus weighed 35lbs (15.8kg) more than those without.
Nothing has yet been proven on this theory, say UK experts.
Previous research has shown that chicken or mice injected with similar types of viruses showed a statistically significant weight gain...
Study Clarifies Obesity-Infertility Link
Being obese has long been linked to infertility in females, but researchers may have been wrong about how the link was forged, a new study suggests.
Doctors and scientists have thought that the fertility problems were caused by resistance to the hormone insulin. Chronically high levels of insulin often accompany obesity, eventually making muscles and other tissues impervious to the hormone’s signals.
A new study in mice shows that the pituitary gland, which helps regulate the release of fertility-associated hormones, remains sensitive to insulin. But in obese mice, insulin’s constant signaling to release the fertility hormones leads to an overabundance of those hormones, and consequently infertility, researchers report in the Sept. 8 Cell Metabolism.
The discovery firmly ties metabolism to fertility in an unexpected way and may have implications for treating women with a condition known as polycystic ovary syndrome, which is characterized by abnormal menstrual cycles and is often associated with obesity and type 2 diabetes...
Doctors and scientists have thought that the fertility problems were caused by resistance to the hormone insulin. Chronically high levels of insulin often accompany obesity, eventually making muscles and other tissues impervious to the hormone’s signals.
A new study in mice shows that the pituitary gland, which helps regulate the release of fertility-associated hormones, remains sensitive to insulin. But in obese mice, insulin’s constant signaling to release the fertility hormones leads to an overabundance of those hormones, and consequently infertility, researchers report in the Sept. 8 Cell Metabolism.
The discovery firmly ties metabolism to fertility in an unexpected way and may have implications for treating women with a condition known as polycystic ovary syndrome, which is characterized by abnormal menstrual cycles and is often associated with obesity and type 2 diabetes...
Poor biological clock leads to obesity
UC San Diego biologists have discovered biological clocks of mammals are related to development of obesity and diabetes.
It also raises the possibility that some of the rise in diabetes could be a consequence of disturbances in sleep-wake cycles from our increasingly around-the-clock lifestyles.
"We know that mice that don't have good biological clocks tend to develop diabetes and obesity. And we know that mice that have developed diabetes and obesity tend not to have very good biological clocks," Nature quoted Steve Kay at UC San Diego, as saying.
"But what we found that's so significant is that a particular biological clock protein, cryptochrome, is actually regulating how the hormone that regulates glucose production in the liver works in a very specific way," he added.
The study also indicates why shift workers, whose biological clocks are often out of step, also have a greater risk of developing obesity and insulin resistance...
It also raises the possibility that some of the rise in diabetes could be a consequence of disturbances in sleep-wake cycles from our increasingly around-the-clock lifestyles.
"We know that mice that don't have good biological clocks tend to develop diabetes and obesity. And we know that mice that have developed diabetes and obesity tend not to have very good biological clocks," Nature quoted Steve Kay at UC San Diego, as saying.
"But what we found that's so significant is that a particular biological clock protein, cryptochrome, is actually regulating how the hormone that regulates glucose production in the liver works in a very specific way," he added.
The study also indicates why shift workers, whose biological clocks are often out of step, also have a greater risk of developing obesity and insulin resistance...
U.S. animal study shows vitamin D protects against obesity-induced endometrial cancer
Findings from an animal study suggest that obese women can reduce their increased risk of endometrial disease if they take vitamin D supplements, say researchers at the Georgetown University Lombardi Comprehensive Cancer Center.
The scientists report in Cancer Prevention Research published online Tuesday that 25 percent of obese mice fed a vitamin D supplemented diet developed endometrial cancer, while 67 percent of obese mice not treated with the vitamin developed cancer. They also report that vitamin D offered no protective effects for normal weight mice; whether or not they used the vitamin, about 60 percent of these mice developed cancer.
All of the mice were genetically predisposed to develop endometrial cancer, because they were missing one of their two PTEN tumor suppressor genes, loss of which is strongly linked to development of human endometrial cancer. Obesity is also a strong known risk factor, researchers say.
"Vitamin D has been shown to be helpful in a number of cancers, but for endometrial cancer, our study suggests it protects only against cancer that develops due to obesity," says the study's lead investigator, Leena Hilakivi-Clarke, a professor of Oncology. "Still, if these results are confirmed in women, use of vitamin D may be a wonderfully simple way to reduce endometrial cancer risk...
The scientists report in Cancer Prevention Research published online Tuesday that 25 percent of obese mice fed a vitamin D supplemented diet developed endometrial cancer, while 67 percent of obese mice not treated with the vitamin developed cancer. They also report that vitamin D offered no protective effects for normal weight mice; whether or not they used the vitamin, about 60 percent of these mice developed cancer.
All of the mice were genetically predisposed to develop endometrial cancer, because they were missing one of their two PTEN tumor suppressor genes, loss of which is strongly linked to development of human endometrial cancer. Obesity is also a strong known risk factor, researchers say.
"Vitamin D has been shown to be helpful in a number of cancers, but for endometrial cancer, our study suggests it protects only against cancer that develops due to obesity," says the study's lead investigator, Leena Hilakivi-Clarke, a professor of Oncology. "Still, if these results are confirmed in women, use of vitamin D may be a wonderfully simple way to reduce endometrial cancer risk...
Sunday, September 05, 2010
Reset your body clock? Maybe, new study suggests
Scientists have used experimental drugs being developed by Pfizer to reset and restart the body clock of mice in a lab and say their work may offer clues on a range of human disorders, from jetlag to bipolar disorder.
The drugs, which are not yet available in a form suitable for humans and could take many years to develop into human medicines, work by altering the activity of an enzyme which helps set the speed of the body clock.
Researchers say they could potentially restore rhythms in people whose body clocks are messed up by shift work, or in psychiatric disorders like depression, and may even have implications for metabolic problems such as obesity...
The drugs, which are not yet available in a form suitable for humans and could take many years to develop into human medicines, work by altering the activity of an enzyme which helps set the speed of the body clock.
Researchers say they could potentially restore rhythms in people whose body clocks are messed up by shift work, or in psychiatric disorders like depression, and may even have implications for metabolic problems such as obesity...
'Sprouty' protein could be a therapeutic target for obesity, osteoporosis
A newly discovered protein termed as 'sprouty' protein could be the answer to obesity and/or osteoporosis, as well as diabetes, osteoarthritis and heart disease.
Scientists from Maine report findings on the protein that could regulate body fat and bone mass.
They found that the more of this protein that the transgenic mice expressed, the leaner and stronger they became, and when mice with low levels of the Sprouty protein were made to express more of it, they lost weight and increased bone density.
Results showed that the mice with the deleted Sprouty gene had increased body fat and loss of bone mass similar to osteoporosis as compared to normal mice. Adding more Sprouty protein then reversed bone loss. The group with excess Sprouty expression produced lean mice with increased bone mass...
Scientists from Maine report findings on the protein that could regulate body fat and bone mass.
They found that the more of this protein that the transgenic mice expressed, the leaner and stronger they became, and when mice with low levels of the Sprouty protein were made to express more of it, they lost weight and increased bone density.
Results showed that the mice with the deleted Sprouty gene had increased body fat and loss of bone mass similar to osteoporosis as compared to normal mice. Adding more Sprouty protein then reversed bone loss. The group with excess Sprouty expression produced lean mice with increased bone mass...
Eating at right time a must to keep obesity at bay
Eating less and exercising more to keep obesity at bay might not be enough. Now there is new evidence to show that eating at the right time is also a must for weight loss.
A Northwestern University study has found that eating at irregular times, especially when the body wants to sleep, influences weight gain.
"How or why a person gains weight is very complicated, but it clearly is not just calories in and calories out," said Fred Turek, neurobiology and physiology professor at the Weinberg College of Arts and Sciences and director of the Centre for Sleep and Circadian Biology.
The findings could have implications for developing strategies to combat obesity in humans, as the US and the world battle what has been called an "obesity epidemic". More than 300 million adults worldwide are obese, including more than a third of American adults.
"Their schedules force them to eat at times that conflict with their natural body rhythms. This was one piece of evidence that got us thinking -- eating at the wrong time might be contributing to weight gain," says Arble.
Simply modifying the time of feeding alone can greatly affect body weight, the researchers found, says a university statement.
Mice that were fed a high-fat diet during normal sleeping hours gained significantly more weight (a 48 percent increase) than mice eating the same type and amount of food during naturally wakeful hours (a 20 percent increase).
A Northwestern University study has found that eating at irregular times, especially when the body wants to sleep, influences weight gain.
"How or why a person gains weight is very complicated, but it clearly is not just calories in and calories out," said Fred Turek, neurobiology and physiology professor at the Weinberg College of Arts and Sciences and director of the Centre for Sleep and Circadian Biology.
The findings could have implications for developing strategies to combat obesity in humans, as the US and the world battle what has been called an "obesity epidemic". More than 300 million adults worldwide are obese, including more than a third of American adults.
"Their schedules force them to eat at times that conflict with their natural body rhythms. This was one piece of evidence that got us thinking -- eating at the wrong time might be contributing to weight gain," says Arble.
Simply modifying the time of feeding alone can greatly affect body weight, the researchers found, says a university statement.
Mice that were fed a high-fat diet during normal sleeping hours gained significantly more weight (a 48 percent increase) than mice eating the same type and amount of food during naturally wakeful hours (a 20 percent increase).
Mouse Study May Help Explain Fish Oil's Benefits
Feeding obese mice omega-3 fatty acids reduced inflammation that can lead to diabetes, a new study finds.
Fish oil supplements that contain high levels of omega-3 fatty acids are one of the most popular dietary supplements in the United States. While omega-3 fatty acids are widely believed to be beneficial, exactly how they work hasn't been well understood, said study co-author Saswata Talukdar, a post-doctoral fellow at University of California, San Diego.
By studying fat tissue in the mice consuming fish oil, researchers found omega-3 fatty acids seem to act on a particular receptor on cells, GPR120, which, when activated, blocks inflammatory processes.
Chronic inflammation can lead to insulin resistance, a precursor to diabetes.
Therefore, "if we can fix the inflammation part, it's possible that we could prevent insulin resistance or even ameliorate diabetes," Talukdar explained.
The study was published in the Sept. 3 issue of the journal Cell...
Fish oil supplements that contain high levels of omega-3 fatty acids are one of the most popular dietary supplements in the United States. While omega-3 fatty acids are widely believed to be beneficial, exactly how they work hasn't been well understood, said study co-author Saswata Talukdar, a post-doctoral fellow at University of California, San Diego.
By studying fat tissue in the mice consuming fish oil, researchers found omega-3 fatty acids seem to act on a particular receptor on cells, GPR120, which, when activated, blocks inflammatory processes.
Chronic inflammation can lead to insulin resistance, a precursor to diabetes.
Therefore, "if we can fix the inflammation part, it's possible that we could prevent insulin resistance or even ameliorate diabetes," Talukdar explained.
The study was published in the Sept. 3 issue of the journal Cell...
Born lazy: how genes dictate our love of exercise
Researchers discovered that the love of wanting to keep fit is in your genes and can be passed on from generation to generation.
Conversely, the same is true about being a couch potato.
In the future, people who suffer from laziness could be treated with medicine that targets the genes that specifically promote activity.
Scientists from the University of California found that on laboratory mice activity levels could be enhanced by selective breeding – the process of breeding animals for particular genetic traits.
Their study showed that mice bred to enjoy running produce offspring that also like it, showing that the baby mice had inherited the trait of high activity.
Professor Theodore Garland Jr, a biologist and lead author, said: "Our findings have implications for human health...
Conversely, the same is true about being a couch potato.
In the future, people who suffer from laziness could be treated with medicine that targets the genes that specifically promote activity.
Scientists from the University of California found that on laboratory mice activity levels could be enhanced by selective breeding – the process of breeding animals for particular genetic traits.
Their study showed that mice bred to enjoy running produce offspring that also like it, showing that the baby mice had inherited the trait of high activity.
Professor Theodore Garland Jr, a biologist and lead author, said: "Our findings have implications for human health...
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