Obesity Weekend Roundup, November 8, 2013 | Dr. Sharma's …

As not everyone may have a chance during the week to read every post, here’s a roundup of last week’s posts:

Have a great Sunday! (or what is left of it)

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DNA flaw boosts cancer risk from diabetes—study

In this Friday, March 2, 2012, file photo, DNA samples are processed at the New York State Police Forensic Investigation Center in Albany, New York. A DNA flaw may explain why people with Type 2 diabetes are more prone to blood cancers than the rest of the population, a study said Sunday, July 14, 2013. AP PHOTO/MIKE GROLL

PARIS—A DNA flaw may explain why people with Type 2 diabetes are more prone to blood cancers than the rest of the population, a study said Sunday.

Doctors have long known that Type 2 diabetes is associated with leukemia and lymphoma, but the reasons for this have been unclear.

Researchers in France and Britain, looking at blood samples from nearly 7,500 people, including 2,200 patients with Type 2 diabetes, suggest the answer lies in cellular mutations called clonal mosaic events (CMEs).

These are defects that result in some cells having extra copies—or, alternatively, missing copies—of large stretches of genetic code.

Reporting in the journal Nature Genetics, the researchers said that in the general population, CMEs are usually very rare in young people but become more common with aging.

Among people aged over 70, around two percent have these mutations, which gives them a tenfold higher risk of developing blood cancer, previous research has found.

Obesity-Cancer Link Explained By 'Gut Bug' Changes, New …

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Changes in the gut microbiome could help explain why obese mice are more likely to develop liver tumors (inset).
Credit: Eiji Hara/Japanese Foundation for Cancer Research

A long-standing question in medical science has been explaining the obesity-cancer link in humans; previous studies have shown that obesity increases the risk for many illnesses such as diabetes and cancer. But the exact biological mechanism that underlies this link has been elusive.

But now, a new study of mice microbiomes (the communities of trillions of microbes that live in the digestive tract) has revealed a DNA-damaging acid that seems to be the key molecule linking excess weight to cancer.

Researchers at the Cancer Institute at the Japanese Foundation for Cancer Research in Tokyo discovered that obesity in mice alters their microbiota — their intestinal “bug” population — which in turn leads to the unregulated production of an acid molecule called deoxycholic that can cause damage to a cells DNA and eventually cancer (e.g., liver cancer).

To uncover the elusive link, the team — led by Eiji Hara — studied two groups of mice: one lean group that was fed a normal diet, and a second group fed a fat-heavy diet (making them obese). To induce cancer in the mice (which normally don’t get much cancer) they exposed both groups to a cancer causing chemical shortly after birth.

Results of these experiments revealed the identical obesity-cancer link noted in humans: only 5% of the mice in the lean group developed cancer later in life, whereas all the obese mice did. But this result does not mean that diet itself is the primary trigger; when the team reproduced the experiment with mice that were genetically altered to become obese (though fed a normal diet), they found that these mice had an increased incidence of cancer. This seems a clear indication that it is obesity, rather than diet, that made the difference.

Pinning Down the Causal Mechanisms

The researchers found that the obese mice were more prone to live cancer and analysis of their tumors showed increased levels of key signaling molecules called pro-inflammatory cytokines which, as the name suggests, promote inflammation (note: Inflammation has been strongly correlated with tumorogenesis in many studies, but whether it is the cause, or effect, of cancer is still debated).

The team also observed that the obese mice had higher levels of deoxycholic acid (DCA), which is a cellular by-product that results when gut microbes break down bile acid (which is manufactured in the liver). The DCA has been shown previously to damage DNA and is associated with some human cancers.

With the confirmation of these two indicators (the elevated DCA and cytokine levels), the researchers next analyzed the mice intestinal tracts. Intriguingly, they observed that the obese mice were host to a different mixture of gut bugs. Specifically, they found that a type of bacteria known as gram-positive bacteria (which have a single, thick cell wall) were far more prevalent in the fatter mice.

When the team treated the obese mice with an antibiotic (vancomycin) that targets gram-positive bacteria, the result was reduced levels of DCA and a reduced incidence of cancer. Further, when they directly targeted the DCA — by slowing bile acid breakdown or stimulating more bile acid secretion into the gut — they again found a reduced incidence of cancer (and giving them increased doses of DCA brought the cancer risk back up).

“I was very surprised by the process,” Hara says. “We never expected that changes in the gut microbiota could cause the higher risk of cancer.” [source]

The gut microbiota has been the focus of intense research just in the past two years and researchers have noted many links between the composition and activity of our microbiomes and various diseases (such as inflammatory bowel disease, certain allergies, and heart disease).

These recent findings by Hara et al lend additional support to the once controversial ‘germ theory” of cancer causation: that bacteria can be primary contributors to the development of cancer (note: the helicobacter pylori bacterium was  shown to cause stomach cancer nearly a decade ago). These results may help doctors better predict — and even prevent — the disease.

However, more research is needed to demonstrate that the same mechanisms are at work in humans, who possess different cellular “micro-environments” than mice.

Results of the experiments were reported on-line June 26, 2013, in the journal in Nature.

Some source material for this post cam from the Science NOW article:‘Gut Bugs Could Explain Obesity-Cancer Link’ by Gisela Telis



Michael Ricciardi (362 Posts)

Michael Ricciardi is a well-published writer of science/nature/technology articles and essays, poetry and short fiction. Michael has interviewed dozen of scientists from many scientific fields, including Brain Greene, Paul Steinhardt, and Nobel Laureate Ilya Progogine (deceased).
Michael was trained as a naturalist and taught ecology and natural science on Cape Cod, Mass. from 1986-1991. His first arts grant was for production of the environmental (video) documentary ‘The Jones River – A Natural History’, 1987-88 (Kingston, Mass.).
Michael is also an award winning, internationally screened video artist. Two of his more recent short videos; ‘A Time of Water Bountiful’ and ‘My Name is HAM’ (an “imagined memoir” about the first chimp in space), and several other short videos, can be viewed on his website (http://www.chaosmosis.net).
Michael currently lives in Seattle, Washington.

Type 2 Diabetes: The Search For An Epigenetic Fix

Type 2 diabetes has a strong hereditary component, and while we can’t change the genes we were born with, if epigenetics says a father eating a Twinkie before conception can lead to bad grades for the child in high school, why can’t we modify the function of the genes through the epigenetic changes that take place in the course of life?

Perhaps we can, according to a study from Lund University in Sweden. Epigenetic changes are usually described as a link between heredity and environment and come about as a result of factors like medication, diet and drugs and the researchers from Lund have now demonstrated that half of the known genetic risk variants for type 2 diabetes can be influenced by epigenetic changes that in turn influence the function of the insulin-producing cells.

The epigenetic factor that has been studied is a chemical change on the DNA strand following a certain pattern – DNA methylation. 

“This means that we gain a tool to influence the function of the risk genes, improve insulin release and thereby reduce the risk of diabetes”, says Charlotte Ling at Lund University Diabetes Centre. “We have shown that 19 of 40 known genetic risk variants for type 2 diabetes are affected by DNA methylation, which in turn changes the function of the insulin-producing cells. This is important. Many researchers have put a lot of time and resources into mapping our genome and finding genetic risk markers for diabetes and other diseases. We know that there are genetic variants that increase the risk of type 2 diabetes, but in most cases the reasons why this happens are still not known.

“The next step is to find this out and after this study of the genetic risk variants, we can say that in some cases the increased risk is probably due to varying degrees of DNA methylation.”

The research group has studied insulin-producing cells from 84 deceased donors, the first epigenetic study to be carried out on the 40 risk markers for type 2 diabetes.

The present study shows that DNA methylation of genetic risk variants for diabetes influence the insulin-producing cells in various different ways, such as the amount of insulin they contain and the amount they are able to release into the blood stream.

“The next step in our work is to test whether we can reduce the risk of type 2 diabetes by changing the degree of DNA methylation in the genetic risk variants for the disease.”

Published in Diabetologia.

Diabetes reduces sperm count, damages DNA in men: Study

MUMBAI: Diabetic men are twice as likely to suffer from DNA damage to sperms than healthy individuals, an ongoing study by Jaslok Hospital and Research Centre has revealed. The study also showed that diabetes significantly reduced sperm count and affected the movement and appearance of sperm.

Doctors said the findings are worrying, especially when India has emerged as the diabetes capital of the world. Also, with diabetes affecting more and more young people in the country, the study has sent alarm bells ringing.

The study found that diabetic men were nearly three times more likely to suffer from sperm apoptosis— self-destruction of a cell due to break-up of the DNA—than healthy individuals.

Fragmented or broken DNA may not only lead to fertility issues but also higher miscarriage rates in couples.

Dr Firuza Parikh, director of the Jaslok Hospital’s IVF and genetics centre, said the findings were in conjunction with global observations that diabetes could contribute to changing the morphology or the look of sperm. The study showed that in diabetic men, 92% sperm looked abnormal whereas only 11% healthy donors showed abnormality.

Diabetic men also fared poorly in sperm count and motility—the agility of a sperm to fertilize an egg. In diabetic men, sperm motility hovered around 22% while it was more than double in case of those who did not suffer from the disease. Sperm count in diabetic men was found to be less than half of that of healthy individuals.

The study, initiated about three years ago by the Pedder Road hospital’s assisted reproduction and genetics department, compared the sperm quality in 120 diabetic and non-diabetic men in the 24-45 age group. Smokers were excluded to avoid any interference in the findings.

Dr Arundhati Athalye and Dr Meenal Khandeparkar, the main investigators, said the study underlined the need to perform routine DNA fragmentation testing in every diabetic patient seeking infertility treatment as that could be the underlying cause.

Dr Prochi Madon, head of genetics, pointed out that early diagnosis was the key to beat diabetes and associated health problems. “The diabetic men chosen for the study had come to the clinic seeking treatment for infertility.”

In a recent seminar at Jaslok Hospital, Dr Craig Niederberger, head of urology at the University of Illinois in Chicago, stressed that in addition to sperm function tests, it was important to thoroughly evaluate men suffering from infertility. He said the link between low testosterone, male infertility and the risk of prostatic cancer later in life was already established.

But it is not all bad news for young men with diabetes. Parikh said some couples grappling with infertility managed to conceive naturally after working on ways to de-stress. “Lifestyle modification or simple things like taking a vacation have worked for many.”

Excessive alcohol consumption could lead to cancer

A recent study has revealed that abuse of excessive amounts of alcohol may lead to cancer and premature aging. According to www.news.health.com, a decrease in telomeres can be held responsible for several health problems including cancer. Telomeres are the DNA regions found at the end of chromosomes which help maintain the stability of the genes. The research study has found that alcohol consumption drastically affects the length of telomere.

As per www.news.yahoo.com, the team of researchers examined DNA serum of a group of adult alcohol drinkers, all in the same age group with similar lifestyles including diet and stress levels. They were divided into two groups depending on the amount of alcohol consumption. While one group had a routine alcohol consumption of four to five drinks, the other group indulged in more alcohol consumption.

The findings of the research revealed that the group which consumed excessive amount of alcohol had drastically shortened telomere as compared to the other group. Excessive abuse of alcohol is also linked to inflammation and oxidative stress which also lead to telomere shortening. “The decrease we found in telomere length is very sharp, and we were surprised to find such a strong effect at the cellular level,” explained Andrea Baccarelli, lead researcher.

Celebrities who have battled cancer include Rod StewartLance ArmstrongBob Marley and Robert DeNiro.

Images: http://www.sxc.hu/photo/866534, http://www.sxc.hu/photo/937586

Dog slobber could help treat cancer

Recently conducted research has revealed that DNA found on the tongue of a dog could prove out to be an essential breakthrough cure for rare type of cancers affecting both dogs and humans. According to www.foxnews.com, the study has been conducted by the researchers at the Van Andel Research Institute (VARI) and the Translational Genomics Research Institute (TGen).

During the study, samples of the blood, saliva and tumour were used by the researchers to test the prospective treatment for the cancer in dogs. This study was approved by Morris Animal Foundation and American Kennel Club.

As per www.ushour.com, these cancer types were essentially found in human beings and lately have been showing signs in dogs too. The team of researchers are hopeful of finding some success in determining the real genomic cause of the diseases. The DNA samples have helped the scientists better understand the disease and to work on its prospective treatment.

“We’re proud to be part of such an innovative approach that fully supports our mission of providing total lifetime care for pets, and one that will offer hope to people and dogs who are suffering from these illnesses,” remarked Phil Francis, Executive chairman, PetSmart.

Celebrities who have suffered from breast cancer include Christine ApplegateBetty FordKylie Minogue and Melissa Etheridge.

Jade Goody lost her battle to cervical cancer in 2009.

Patrick Swayze is just one celebrity who died of pancreatic cancer.

Images: http://www.sxc.hu/photo/1240498, http://www.sxc.hu/photo/1019247

New blood test could revolutionize cancer treatment

Personalized blood tests on patients with cancer can tell whether treatment is working, or whether disease has returned. A sample of the tumor is used to identify the unique cancer gene sequence, meaning the blood test identifies tumor “rearrangements” of the DNA. This method of “fingerprinting” the cancer can reportedly track the development of the cancer in the specific individual’s body.

“[This technique] will allow us to measure the amount of cancer in any clinical specimen as soon as the cancer is identified by biopsy,” study co-author Dr. Luis Diaz explains to Business Weekly. “This can then be scanned for gene rearrangements, which will then be used as a template to track that particular cancer.”

While the testing is still expensive at the moment, doctors are hoping the price will fall over time to make it more affordable to more people fighting cancer.

“This is a great tool towards made-to-measure cancer care,” Professor Victor Velculescu of the Johns Hopkins University in Baltimore told the Telegraph.co.uk. “This will be a step towards cancer becoming a manageable chronic disease rather than an acute terminal disease,” he continued.  “People will be able to manage their own cancer.”

The study will be published in next week’s issue of Science Translational Medicine.

Image: http://commons.wikimedia.org/wiki/File:Gel_electrophoresis_2.jpg;

DNA mutation linked to childhood obesity, study finds

A study conducted on 300 children (most weighing over 200 pounds at the age of 10), specifically targetting their DNA. The research has found that some children who are obese could have a part of their DNA missing, which causes overeating, therefore causing weight gain.

The Chicago Tribune reports that the researches looked at the DNA of the obese children, and found that in some, there were sections of DNA missing. This deletion of DNA causes a large problem because it removes a gene that the brain needs to respond to an appetite-controlling hormone.

The Daily Mirror reports that co-leader of the study, Dr. Sadaf Farooqi of Cambridge University, said children with a chromosome 16 DNA deletion “have a very strong drive to eat.

“They’re very, very hungry, they always want to eat.”

According to Dr. Farooqi, the research findings come as a blessing to many families affected by obese children.

“It’s been an emotional rollercoaster for them,” she said.

“This study shows that severe obesity is a serious medical issue that deserves scientific investigation.

“It adds to the growing weight of evidence that a wide range of genetic variants can produce a strong drive to eat.”

Obesity has become a health problem in developed nations across the globe, with cases of childhood obesity unfortunately becoming more and more common.

Obesity is one of the most serious health conditions of the 21st century, and a leading cause of death. Obesity may simply be defined as too much body fat – so much so, that is has a serious effect on a person’s health.

Image: http://commons.wikimedia.org/wiki/File:Obesity6.JPG;
Author: Central_Obesity_008.jpgFatM1ke