Microbe overhaul. Gastric bypass surgery changes the community of microbes in the gut, and a study suggests the new population might drive weight loss.
Credit: Life in View/Science Source
Posted on 03/27/2013 9:31:31 PM PDT by neverdem
Usually, science starts in the lab and then moves to patients. Gastric bypass surgery has taken the opposite path. Originally offered as a radical treatment for severe obesity, the surgery's effects on the digestive system and metabolism have turned out to be far more mysterious and fascinating than anyone expected. Now, a new study probes another of the surgery's effects: its impact on microbes in the gut and how changing these microscopic communities might drive weight loss.
The most popular type of gastric bypass surgery is called Roux-en-Y. Surgeons make a small pouch from the top of the stomach and separate it from the rest of the organ, then connect that directly to the middle of the small intestine. Originally, doctors believed that patients who underwent gastric bypass lost weight for a simple reason: Their stomach couldn't hold as much food, and they couldn't absorb as many nutrients.
But quickly, the picture got more complicated. In many people with type 2 diabetes, the disease vanishes almost immediately after surgery, too quickly to be explained by the gradual weight loss that happens later. Patients also describe not being as hungry, or craving foods like salad that they hadn't liked much before. "Food doesn't call out to them anymore," says Lee Kaplan, a molecular biologist and gastroenterologist at Harvard Medical School and Massachusetts General Hospital, both in Boston.
There are likely many mechanisms at work. Some may stem directly from how the altered digestive system works—secreting different levels of hormones, for example—or changes in nerve cells that communicate with the gut. Kaplan and Harvard University microbiologist Peter Turnbaugh, who had been studying gut microbes in obese and lean animals, were intrigued by other work suggesting that in both humans and rats, the microbial balance in fecal samples changed after gastric bypass. Along with a postdoc in Kaplan's lab, Alice Liou, they decided to test whether the surgery itself caused the changes in the population of gut microbes—known as the microbiota.
The researchers' colleagues divvied mice into three groups: those getting gastric bypass surgery; those given sham surgery; and those given sham surgery whose diet was restricted, to match what the bypass group weighed after the operation. In this way, the scientists could separate out the effects of surgery itself on microbial communities from the effects of losing weight or consuming less food. For 23 animals overall, they analyzed fecal samples before surgery and then weekly for 3 months. The result: Although the balance of microbes changed in both the dieting animals and those given bypass surgery, the difference was more dramatic in the surgery group. Those mice displayed specific patterns in their gut, the team reports today in Science Translational Medicine, including a boost in three types of bacteria called Bacteroidetes, Verrucomicrobia, and Proteobacteria. All are common in the guts of healthy people.
In a sense, the postop bacterial changes are not surprising, says endocrinologist David Cummings at the University of Washington, Seattle, (although he notes it's a "herculean feat" to manage gastric bypass surgery in animals as tiny as mice). Because it bypasses part of the stomach and small intestine, the surgery alters the intestinal environment, changing elements such as pH and bile concentrations.
The big step forward, Cummings says, is what the researchers did next: They performed a series of gut microbe transplants. Animals in each of the three groups—gastric bypass, sham surgery, and restricted diets—were killed and samples of their gut microbe communities diluted. Those were infused into the stomachs of mice raised in a germ-free environment and, therefore, without a gut microbiome of their own. The animals that got microbes from the gastric bypass donors lost about 5% of their body weight in 2 weeks—even though they weren't eating any less than controls. Microbes transplanted from the dieting animals that had had sham surgery didn't lead to any notable weight loss in the recipients.
"Something about the surgery changes the way this whole process is regulated," Kaplan says. He suspects microbial modifications linked to the bypass surgery—if they apply to humans—could help explain shifts in metabolism that doctors have long observed. The experiments were partially funded by Ethicon, a subsidiary of Johnson & Johnson, and Liou, Turnbaugh, and Kaplan have filed a patent application related to the research.
"It's now worth figuring out" how and why certain bacteria could lead to weight loss, Cummings says. Another important question, Turnbaugh says, is whether the transplants will have the same effect in animals who weren't raised in a sterile environment and who already have their own gut microbiome. These animals would more closely mimic people undergoing gastric bypass surgery. It's something he, Kaplan, and their colleagues are keen to learn more about.
I’ve been thinking.
Where would all the fat go?
Transcendental dieting...
Is There a Surgical Cure for Diabetes?
http://www.thedailybeast.com/newsweek/2008/08/24/is-there-a-surgical-cure-for-diabetes.html
Can stomach surgery cure diabetes?
http://www.webmd.boots.com/diabetes/news/20090403/can_stomach_surgery_cure_diabetes#
Gastric Bypass Surgery Can Reverse Diabetes
http://abcnews.go.com/Health/diabetes-organization-recommends-surgery-treatment-option/story?id=13241219
FReepmail me if you want on or off my combined microbiology/immunology ping list.
its a billion dollar industry and of course they're going to push it on people...
Thanks for the kinks.
Burned for energy.
“Where would all the fat go?”
Making soap or explosives.
I can get it for free from the VA hospital but am holding back.
Yeah, was non-diabetic for about five years. Now, back to diabetes.
However, since I can’t and don’t eat the caloric intake (assuming my carb intake was too large) I can say that it truly isn’t how much you eat, but WHAT you eat when you are diabetic.
Are you still svelt? (If I may ask?) That's gotta be better for joints, blood pressure, cholesterol, general energy and mood.
(s) nully who is contemplating bypass surgery for himself...
This study shows that it keeps working for the vast majority of patients after 5 years.
Surg Obes Relat Dis. 2012 Aug 7. pii: S1550-7289(12)00278-X. doi: 10.1016/j.soard.2012.07.017. [Epub ahead of print]
Roux-en-Y gastric bypass stands the test of time: 5-year results in low body mass index (30-35 kg/m(2)) Indian patients with type 2 diabetes mellitus.
Lakdawala M, Shaikh S, Bandukwala S, Remedios C, Shah M, Bhasker AG.
Source
Center for Obesity and Diabetes Surgery, Mumbai, India; Department of Minimal Access and Bariatric Surgery, Saifee Hospital, Mumbai, India; Lilavati Hospital and Research Center, Mumbai, India.
Abstract
BACKGROUND:
Our objective was to evaluate the long-term results of laparoscopic Roux-en-Y gastric bypass on excess weight loss, remission of the metabolic syndrome, and complications in Indian patients with uncontrolled type 2 diabetes mellitus (T2DM) with a body mass index of 30-35 kg/m(2). The setting was a corporate hospital in Mumbai, India.
METHODS:
The present prospective observational study was begun in January 2006. A total of 52 patients with uncontrolled T2DM and a body mass index of 30-35 kg/m(2) elected to undergo laparoscopic Roux-en-Y gastric bypass. The duration of T2DM was 3.5-14.5 years (median 8.4). Of the 52 patients, 61.5% had hypertension and 59.6% had dyslipidemia. Remission of T2DM and other components of the metabolic syndrome were assessed. All patients were followed up for 5 years.
RESULTS:
The median percentage of excess weight loss was 72.2% at 1 year and 67.8% at 5 years. Of the 52 patients, 84.6% had achieved euglycemia and 73.1% had achieved complete remission, 23.1% partial remission, and 3.84% no remission at 1 year. Weight regain occurred in 8 patients. They required antihypertensive drugs and statins, decreasing the complete remission rate to 57.7% and partial remission rate to 38.5% at 5 years. However, 96.2% improvement in metabolic status was found at the end of 5 years.
CONCLUSION:
Laparoscopic Roux-en-Y gastric bypass is a safe, efficacious, and cost-effective treatment for uncontrolled T2DM in patients with a body mass index of 30-35 kg/m(2). Early-onset T2DM, better weight loss, and greater C-peptide levels were predictors of success after surgery. The improvement after surgery in hyperglycemia, hypertension, and dyslipidemia could help in controlling the occurrence of micro- and macrovascular complications and decrease the morbidity and mortality associated with T2DM.
Copyright © 2012 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.
I’m not super thin, but I am certainly not what I was. I have stagnated at about 40 lbs overweight, but kept this weight for nearly 9 years now. That has got to be better thank yo yoing.
But I can also fit into booths, amusement park rides, shop for normal clothes, etc...
I’d have to lose three times that to be merely overweight.
I think the people who make the charts are in collusion with the same people who think an anorexic 12 year old is a perfect fashion model.
Oh, that BMI index is ridiculous and I believe padded to make insurance companies get more premiums.
I’m glad you showed up on my other thread. Your screen name is a bit much otherwise.
I wonder if the resultant gut microbiome is the same with gastric banding when compared with a Roux-en-Y bypass, and are the effects on metabolism the same, all other differences notwithstanding?
A good question for which they may not be an answer right now. Intestinal flora is just getting started as a study, and so far it is pretty limited to bacteria, and some parasites.
Not only have they not even begun serious research about viruses, clearly the dominant form in the flora, but now it turns out there’s another *domain* involved (of Archaea)!
That startled me, because like most, I associate them as being extremophiles, living near ocean trench volcanic vents, for example.
In perspective, I suppose that humans have more in common with plants, than Archaea have in common with bacteria.
There was an interesting paper in one of the bigs (Nature or Science) a few months back, that suggested (especially in press writeups) that a Chinese team had produced dramatic weight loss by resetting fat folks’ gut flora with traditional Chinese remedies.
I read it with interest, and wound up wondering how they ever published the paper. The experimental group as an N of 1 (the one experimental subject was a single 278 lb. man) and the control group appeared to have an N of 0. (i.e., there was no control group).
That’s many things, but it ain’t science. It doesn’t disprove the thesis either, and there are a number of things in this new paper that suggest there might actually be something to flora as either a cause or a consequence of obesity. You can’t see which way the arrow of causation points... yet.
The beauty of science is that they keep plugging till they understand. It’s brought us many wonders in these recent decades, and if the gov. doesn’t make a complete botch of it, it will bring us more wonders at an accelerating rate.
Still, most overweight Americans are overweight as a result of too little activity and too much intake... simple thermodynamics, not advanced biology.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.