Microbiome Bites May 9th: The Roles of the Microbiome in Weight Loss and Osteoarthritis
1. Sleep Affects Metabolism and the Microbiome
In a study published in the American Journal of Obstetrics and Gynecology, scientists show that changing the circadian clock in mice can alter how the body responds to diet.
Researchers genetically disrupted the Npas2 gene in the liver, which controls circadian rhythms. They then put the mice on a diet (restricted feeding) and limited their feeding time to a 4-hour window (instead of the usual 12 hours).
The scientists found that changing the circadian clock in the liver altered the gut microbiome. Two groups of mice ate the same amount of food and both groups lost weight. However, the mice lacking the Npas2 gene lost less weight than the control mice.
The team thinks that their research will have lead to new solutions for people who struggle to lose weight through caloric restriction (dieting).
2. Osteoarthritis Pain and the Microbiome are Linked
Researchers from the Netherlands have discovered a link between the gut microbiome and pain in patients with osteoarthritis.
Obesity is a well-known risk factor for osteoarthritis and microbiome alterations are clear in obese individuals.
Obesity leads to increased intestinal permeability (leaky gut), which means that things like bacterial endotoxins can more-easily enter the bloodstream.
The researchers hypothesized that these bacterial endotoxins (toxins produced within some bacteria that are only released when the bacteria disintegrate), which are increased in obese individuals, can activate the immune system. This activation leads to low-grade inflammation, which in-turn increases the severity and risk of osteoarthritis.
The team analyzed the gut microbiomes of 1444 participants.
They found no overall association between variations in the gut microbiome and osteoarthritis.
However, when they adjusted for BMI, age and gender they that the Streptococcus species of bacteria was associated with knee osteoarthritis.
The researchers speculate that little fragments of membrane (vesicles) from the bacteria can get from the gut into the bloodstream and activate cells of the immune system. These activated cells in-turn cause inflammation within the joint.