The link between the gut microbiome and obesity seems clear, but just how changes to gut bacteria can cause weight gain is not.
A new study in mice shows that drug-induced changes to the gut microbiome can cause obesity by reducing the resting metabolic rate - the calories burned while sleeping or resting. The findings, published in the journal eBiomedicine, highlight the critical role of gut microbes in energy balance and suggest that unhealthy microbiome shifts can lead to weight gain and obesity by altering resting metabolism.
Researchers focused on the effects of risperidone, an antipsychotic drug that causes significant weight gain in patients. Risperidone is used to treat various psychiatric disorders in adults and children, including autism, bipolar disorder, and schizophrenia, and prescribing rates for children have increased nearly eight-fold over the last two decades.
In an earlier study, researchers compared patients taking risperidone long-term to patients who were not on the drug. They found that weight gain was correlated with a significant shift in the composition of the patients' gut microbiomes. These results were published in Translational Psychiatry.
In the new eBiomedicine study, researchers wanted to find out how this risperidone-induced microbiome shift causes weight gain. Mirroring the human studies, the researchers showed that risperidone causes weight gain in mice (an extra 2.5 grams, or approximately 10 percent of the total body mass, over two months compared to controls) and significantly alters the bacterial composition of the mouse microbiome. They then showed that the altered microbiome causes a reduction in resting metabolic rate that is entirely responsible for the excess weight gain.
The researchers discovered there was no change in aerobic (oxygen-dependent) resting metabolic rate for mice fed risperidone compared to control mice, but there was a significant decrease in non-aerobic resting metabolic rate sufficient to account for the animals' weight gain.
"It's about a 16 percent change in resting metabolic rate, which is enormous," author says. "It would be 29 pounds of fat gained every year for an average human."
"That is the equivalent of eating one additional cheeseburger every single day," adds author.
To prove that it was the "shifted" microbiome that was responsible for this metabolic change and the weight gain, the researchers transferred the microbiome from risperidone-fed mice into control mice and saw the same effect: decreased resting metabolic rate and increased weight gain. Moreover, they found it wasn't just the bacteria that could produce this effect. Transferring just the bacteriophage (phage) - viruses that infect the microbiome bacteria -- was sufficient to reduce resting metabolic rate and cause weight gain in control mice.
The results may suggest that manipulating resting metabolic rate, specifically by targeting the gut microbiome, could represent a new approach to treating obesity. Alternatively, preventing unhealthy changes to the microbiome may prove beneficial for patients undergoing risperidone treatment.
http://www.ebiomedicine.com/article/S2352-3964(15)30181-X/abstract
Edited
Latest News
Men with gene mutations are…
By newseditor
Posted 17 May
B cell oxidative phosphoryl…
By newseditor
Posted 17 May
Human brain gene therapy us…
By newseditor
Posted 16 May
Small-molecular mimic of a…
By newseditor
Posted 16 May
Centromere structure and ch…
By newseditor
Posted 16 May
Other Top Stories
How fish brain responds to beta-amyloid challenge?
Read more
Delivering synthetic nanomaterial to prevent the scarring after hea…
Read more
Tooth enamel damage from mutation of a gene
Read more
Brain's emotional center contributes to eating for pleasure!
Read more
Disrupting protein-RNA interaction prevents neurotoxicity in ALS
Read more
Protocols
Breast cancer-on-chip for p…
By newseditor
Posted 16 May
Methods for making and obse…
By newseditor
Posted 15 May
Mime-seq 2.0: a method to s…
By newseditor
Posted 13 May
Improved detection of DNA r…
By newseditor
Posted 09 May
Single-cell adhesive profil…
By newseditor
Posted 07 May
Publications
Obesity-induced blood-brain…
By newseditor
Posted 18 May
CRISPR/Cas9 model of prosta…
By newseditor
Posted 17 May
Modulation of host immunity…
By newseditor
Posted 17 May
Variability in cell divisio…
By newseditor
Posted 17 May
Biallelic BORCS8 variants c…
By newseditor
Posted 17 May
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar