Gut bacteria from wild mice boost health in lab mice

Laboratory mice that are given the gut bacteria of wild mice can survive a deadly flu virus infection and fight colorectal cancer dramatically better than laboratory mice with their own gut bacteria; researchers report (October 19, 2017) in the journal Cell.

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The immunological benefits from the wild mice’s gut bacteria may, in part, explain a persistent problem in disease research: Why disease experiments in lab mice, such as vaccine studies, turn out very differently in humans or other animals. “We think that by restoring the natural ‘microbial identity’ of laboratory mice, we will improve the modeling of complex diseases of free-living mammals, which includes humans and their diseases,” said Barbara Rehermann, M.D., senior author of the paper. Rehermann is chief of the Immunology Section, Liver Diseases Branch, of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “By being so different, natural microbiota will help us to discover protective mechanisms that are relevant in the natural world and absent in the laboratory,” said Stephan Rosshart, M.D., first author of the paper and NIDDK postdoctoral fellow.

Mammals, humans included, depend on their microbiota, the collection of microorganisms they host in and on their bodies. Evolution shapes each animal’s microbiota, favoring populations of organisms that help the animal survive their environment and diseases they encounter. However, laboratory mice are not random house mice plucked from a field or basement. Laboratory mice are carefully bred, fed, and raised in tightly controlled conditions so that each mouse has predictable traits and genetics. This is an excellent advantage in basic biology research, but creating that predictability means that a controlled environment, and not the survival pressures of the outside world, shaped the microbiotas of laboratory mice.

“We hypothesized that this might explain why laboratory mice, while paramount for understanding basic biological phenomena are limited in their predictive utility for modeling complex diseases of humans and other free-living mammals,” said Rosshart. Therefore, the researchers tried to give laboratory mice back what they have lost: A naturally co-evolved wild mouse gut microbiota. The researchers trapped more than 800 wild mice from eight locations across Maryland and the District of Columbia to find healthy, suitable candidates for a gut microbiota donation. They then tested and compared the gut microbiomes (collective genomes of the gut microbiota) of the wild mice (Mus musculus domesticus) and a standard strain of laboratory mice, called C57BL/6, from multiple sources. The researchers confirmed that C57BL/6 mice had distinct gut microbiomes from wild mice.

Researchers then introduced (engrafted) the microbiota of wild mice to pregnant, germ-free C57BL/6 mice. Germ-free mice are raised in a sterile environment and don’t have microbiomes of their own. For a control group comparison, the researchers also engrafted microbiota from regular C57BL/6 mice into a separate group of pregnant, germ-free mice. Four generations later, the mice still carried either the wild microbiomes or the control laboratory microbiomes passed down from their foremothers.

When exposed to a high dose of influenza virus, 92 percent of the laboratory mice with wild microbiomes survived, whereas only 17 percent of laboratory mice and mice in the control group survived. In other experiments, the laboratory mice with wild microbiomes had better outcomes in the face of induced colorectal tumors, whereas the other mice had a higher number of tumors and more severe disease. The beneficial effects of the wild microbiota were associated with reduced inflammation in both models.

The researchers note that more work and evaluation is needed for definitive results, and they hope to improve and expand upon the method of using natural microbiomes in laboratory mice. “We are planning to create a complete microbiological fingerprint of natural microbiota and its potential trans-kingdom interaction by describing all components of the microbiome — for example, viruses and fungi — in parallel and at various body sites,” Rehermann said.

So, it’s ok not to be a germaphobe and let the little critters run free, every now and then!

Adapted from: Rosshart et al. Wild Mouse Gut Microbiota Promotes Host Fitness and Improves Disease ResistanceCell, 2017 DOI: 10.1016/j.cell.2017.09.016

Nutrition Nugget

Use A Vegetable Substitute! Love spaghetti? Try spaghetti squash. Sure it’s not pasta but just try it, you may like it! Love mashed potatoes? Try mashed cauliflower (OMG it’s heavenly! You will never go back to potatoes). Mix in some Greek yogurt to give it a thick, creamy texture like regular mashed potatoes. While vegetables most likely won’t be the carbs you know and love, they’re a good way to make your favorite meals healthier!

Inspirational Nugget

Even when things seem hopeless, life has a way of defying the odds, overcoming the obstacles and coming back strong. So never give up, regardless of how hopeless things may seem. There is ALWAYS a way.

 

 

Whole food diet may help prevent colon cancer, other chronic conditions

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A diet that includes plenty of colorful vegetables and fruits may contain compounds that can stop colon cancer and inflammatory bowel diseases in pigs, according to an international team of researchers. Understanding how these compounds work on a molecular level could be an initial step toward finding treatments for people with cancer, they added. “What we are learning is that food is a double-edge sword — it may promote disease, but it may also help prevent chronic diseases, like colon cancer,” said Jairam K.P. Vanamala, associate professor of food sciences, Penn State. “What we don’t know is, ‘how does this food work on the molecular level?’ This study is a step in that direction.”

In the study, pigs that were served a high calorie diet supplemented with purple-fleshed potatoes had less colonic mucosal interleukin-6 — IL-6 — compared to a control group. IL-6 is a protein that is important in inflammation, and elevated IL-6 levels are correlated with proteins, such as Ki-67, that are linked to the spread and growth of cancer cells, said Vanamala, who also is a faculty member at the Penn State Hershey Cancer Institute. According to the researchers, who reported their findings in a recent issue of the Journal of Nutritional Biochemistry, eating whole foods that contain macronutrients, substances that humans need in large amounts, such as proteins, as well as micro and phytonutrients, such as vitamins, carotenoids and flavonoids, may be effective in altering the IL-6 pathway.

Vanamala said these findings reinforce recent research that suggests cultures with plant-based diets tend to have lower colon cancer rates than cultures with meat-based diets. Colon cancer is the second leading cause of cancer related deaths in the United States and a leading killer in many other Western countries, which tend to include more meat and less fruits and vegetables, he added. While the researchers used purple potatoes in this study, Vanamala said other colorful fruits and vegetables could prompt similar effects. Colorful plants, including the purple potato, contain bioactive compounds, such as anthocyanins and phenolic acids, that have been linked to cancer prevention.

“For example, white potatoes may have helpful compounds, but the purple potatoes have much greater concentrations of these anti-inflammatory, anti-oxidant compounds,” said Vanamala. “We use the purple potato as a model and hope to investigate how other plants can be used in the future.” Another advantage of using whole foods for cancer treatment is that it would benefit the agriculture industry and likely help small farmers around the world. “If this model works, we can see what works in other countries,” Vanamala said. “Instead of promoting a pill, we can promote fruits and vegetables that are very rich in anti-inflammatory compounds to counter the growing problem of chronic disease.”

The researchers fed the animals three different diets: a standard diet with 5 percent fat; a high-calorie diet, with 17 percent added dry fat and 3 to 4 percent added endogenous fat; and a high fat diet supplemented with purple-fleshed potatoes. The expression of IL-6 was six times lower in pigs that ate the purple potato-enhanced feed compared to the control group. Researchers used both uncooked and baked potatoes and found similar effects. Currently, anti-IL-6 drugs are used against certain type of rheumatoid arthritis and are being considered to treat other inflammation-promoted chronic diseases, such as colon cancer. However, these drugs are expensive and can cause side-effects, including drug tolerance.

Vanamala said that the pig model was used because the digestive system is very similar to the human digestive system, more so than in mice. The diet approach to cancer treatment has also shown similar promise in mice, however, he added.

Adapted from: Penn State. (2017, September 21). Whole food diet may help prevent colon cancer, other chronic conditions. ScienceDaily. Retrieved December 13, 2017 from http://www.sciencedaily.com/releases/2017/09/170921101727.htm

Nutrition Tip of the Day

Have a superfood! Most superfoods can be found in the produce aisle, they’re not fancy and they don’t even wear food labels. Add a fruit or veggie to each meal.

Daily Inspiration 

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