New research combines two of my big interests: looking at ways to manipulate the biome to help reduce today’s epidemic of obesity AND using bacteriophages in a productive way.
You’ll all remember that a bacteriophage is a virus that attacks a specific bacteria. (I’ve written about these many times, like here and here.) Our bodies naturally house trillions of them: nature’s way of keeping our bacterial microbiome in check. Like everything, there’s good and bad: alterations to these viruses, which constitute the virome, is now associated with disease. (You can read about that here and here.) On the other hand, research is progressing toward using naturally-occurring phages in lieu of antibiotics: they are harmless, have no side effects, and are targeted to only the pathogen that’s being treated, sparing all the good bacteria.
Scientists at University of Copenhagen in Denmark just published a fascinating animal study. They isolated the virome from lean mice and transplanted it into obese animals. The result: the treated obese mice put on much less weight than their untreated, control peers.[i]
It’s interesting to note that germ-free mice do not develop obesity from a high-calorie diet; but if given the fecal microbiota of humans, they much more rapidly gain weight if the donation is from obese humans, not lean ones
They also noted that the phages protect the mice against glucose intolerance, seen in metabolic syndrome and type 2 diabetes: the body becomes resistant to its own insulin, making it hard for it to lower blood sugar levels appropriately. When given a shot of glucose, the treated mice had the same metabolic response to the sugar as the lean mice. The lead researcher on the study points out that they managed to influence the gut microbiome “…in such a way that the mice with unhealthy lifestyles do not develop some of the common diseases triggered by poor diet…” Of course he is not suggesting that getting onto a good die is not key to treatment – the scientists emphasize that this is not a stand-alone solution and to be effective, should be paired with a healthy and calorie-appropriate diet. [ii]
Fecal transplant is, as you know from reading my blog, being investigated as a treatment for a wide variety of diseases, including obesity. It’s most commonly used to treat recurring clostridim difficile infections. What I find particularly fascinating about this is that the bacteria were not transferred – only the phages, in concentrated form, which modulate the bacterial microbiome – and the treatment was equally as effective. In fact, the paper points out that FVT (fecal virome transplant) has also proved effective for the treatment of c.difficile infections as well! Of course much more research needs to be done, and we don’t yet know if FVT will prove effective in humans, or how long it will last. (That’s where diet and lifestyle changes are likely to play a huge role.)
[i] Torben Sølbeck Rasmussen, Caroline Märta Junker Mentzel, Witold Kot, Josué Leonardo Castro-Mejía, Simone Zuffa, Jonathan Richard Swann, Lars Hestbjerg Hansen, Finn Kvist Vogensen, Axel Kornerup Hansen, Dennis Sandris Nielsen. Faecal virome transplantation decreases symptoms of type 2 diabetes and obesity in a murine model. Gut, 2020; gutjnl-2019-320005 DOI: 10.1136/gutjnl-2019-320005