Want healthy joints? Maybe put down that glass of milk.
A study from the University of Central Florida suggests that a bacterium easily acquired by consuming dairy products, beef, or produce grown in cow manure may trigger development of rheumatoid arthritis (RA) in those who are genetically predisposed to the disease.
The research was based on past findings indicating that irregularities in two related genes called PTPN2/22 increase the risk of the autoimmune disorders Crohn’s disease, Type 1 Diabetes (T1D), and RA. These chronic conditions arise when the body’s defensive cells mistakenly attack its own tissue due to unknown genetic and environmental cues.
"If mutations occur in these genes, the PTPN2/22 protein will not function correctly, thus leading to an overactive immune system that leads to autoimmune disorders," lead author Robert C. Sharp told IFLScience.
Recently, team leader Dr Saleh Naser uncovered a link between the bacteria in question, Mycobacterium avium paratuberculosis (MAP), and both Crohn’s disease and T1D. It appears that the presence of MAP can act like an “on switch” for the abnormal PTPN2/22 in these patients, sending their cell recognition and inflammatory signaling systems into overdrive and cueing the emergence of symptoms.
Knowing that RA is also affected by the PTPN2/22 genes, Naser and his co-authors hypothesized that MAP plays a role in this mysterious disease as well.
“To our knowledge, this is the first study designed to elucidate the molecular cause of inflammation in RA in association with environmental triggers such as MAP,” the authors wrote in Frontiers in Cellular and Infection Microbiology.
They began by analyzing the DNA from blood samples of 70 RA patients and 48 healthy volunteers. Traces of MAP DNA were detected in 34.3 percent of subjects with any type of RA, whereas only 8.3 percent of people without rheumatoid arthritis showed evidence of past exposure to the bacteria.