Newly discovered species of bacteria in the microbiome may be a culprit behind rheumatoid arthritis
By Meagan Chriswell, University of Colorado Anschutz Medical Campus
Aurora (The Conversation)(PTI): Rheumatoid arthritis affects 1 in 100 people worldwide. It causes inflamed, painful and swollen joints, often in the hands and wrists, and can lead to loss of joint function as well as chronic pain and joint deformities and damage.
What causes this condition has been unknown.
In our recently published study, my colleagues and I found an important clue to a potential culprit behind this disease: the bacteria in your gut.
What causes rheumatoid arthritis?
Rheumatoid arthritis is an autoimmune condition, meaning it develops when the body's immune system starts to attack itself. Proteins called antibodies, which usually help fight off viruses and bacteria, begin to attack the joints instead.
The origins of the antibodies that cause rheumatoid arthritis have been an area of study for many years.
Some research has shown that these antibodies can start forming at sites like the mouth, lung and intestines over 10 years before symptoms arise.
But until now, it was unclear why researchers were finding these antibodies in these particular areas.
We wanted to investigate what could trigger the formation of these antibodies. Specifically, we wondered if bacteria in the microbiome, a community of microorganisms that live in the intestines, might be the ones activating the immune response that leads to rheumatoid arthritis.
Since microbes commonly live at the same sites as the antibodies driving rheumatoid arthritis, we hypothesised that these bacteria could be triggering the production of these antibodies.
We reasoned that though these antibodies were meant to attack the bacteria, rheumatoid arthritis develops when they spread beyond the intestines to attack the joints.
First, we sought to identify the intestinal bacteria targeted by these antibodies. To do this, we exposed the bacteria in the feces of a subset of people at risk for developing rheumatoid arthritis to these antibodies, allowing us to isolate just the bacterial species that reacted and bound to the antibodies.
We found that one previously unknown species of bacteria was present in the intestines of around 20 per cent of people who were either diagnosed with rheumatoid arthritis or produce the antibodies that cause the disease.
As a member of the Cherokee Nation of Oklahoma, I suggested we name this species Subdoligranulum didolesgii ( didolesgii means arthritis or rheumatism in Cherokee) as a nod to the contributions that other Indigenous scholars have made to science as well as the fact that rheumatoid arthritis affects Indigenous people at a higher rate than other populations.
Subdoligranulum didolesgii has not been detected in the feces of healthy people before, and it is currently unknown how prevalent this bacteria is in the general population.
We also found that these bacteria can activate specialised immune cells called T cells in people with rheumatoid arthritis.
T cells drive inflammatory responses in the body, and have been linked to the development of different autoimmune diseases.
These findings suggest that these gut bacteria may be activating the immune systems of people with rheumatoid arthritis. But instead of attacking the bacteria, their immune system attacks the joints.
Why this bacteria?
It is still unknown why people with rheumatoid arthritis develop an immune response to Subdoligranulum didolesgii.
But we think it may be the culprit when it comes to rheumatoid arthritis because this bacteria is found only in the intestines of people with rheumatoid arthritis, and not in the intestines of healthy people.
While many immune responses happen in the intestines, they are usually self-contained and do not spread to other areas of the body.
However, we believe that a particularly strong intestinal immune response against Subdoligranulum didolesgii could allow antibodies to bypass the intestinal firewall and spread to the joints.
To confirm our hypothesis, we gave mice an oral dose of Subdoligranulum didolesgii and monitored their reaction.
Within 14 days, the mice began to develop joint swelling and antibodies that attacked their joints.
The future of rheumatoid arthritis treatment
My colleagues and I hope this research can shed light on the origins of rheumatoid arthritis.
Our next goal is to discover how common these bacteria are in the general population and test whether the presence of these bacteria in the gut may lead to the development of rheumatoid arthritis in people.
It's important to note that antibiotics are unlikely to be helpful treatment for the microbiomes of patients with rheumatoid arthritis.
Although Subdoligranulum didolesgii may be triggering an autoimmune response for some people with rheumatoid arthritis, antibiotics eliminate both helpful and harmful bacteria in the gut.
Additionally, removing the bacteria won't necessarily stop the immune system from attacking the joints once it has started.
Nevertheless, we believe that these bacteria can be used as tools to develop treatments for rheumatoid arthritis and hopefully ways to prevent disease from happening in the first place.
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Trouble ‘Miyas’ everywhere only then they will leave Assam: Himanta Biswa Sarma
Says “Himanta Biswa Sarma, BJP are openly against them, we are saying it openly
New Delhi: Assam Chief Minister Himanta Biswa Sarma on Tuesday said that four to five lakh “Miya voters” would be removed from the electoral rolls in the state once the Special Intensive Revision (SIR) of voter lists is carried out. He also made a series of controversial remarks openly targeting the Miya community, a term commonly used in Assam in a derogatory sense to refer to Bengali-speaking Muslims.
Speaking to reporters on the sidelines of an official programme in Digboi in Tinsukia district, Sarma said it was his responsibility to create difficulties for the Miya community and claimed that both he and the BJP were “directly against Miyas”.
“Four to five lakh Miya votes will have to be deleted in Assam when the SIR happens,” Sarma said, adding that such voters “should ideally not be allowed to vote in Assam, but in Bangladesh”. He asserted that the government was ensuring that they would not be able to vote in the state.
The chief minister was responding to questions about notices issued to thousands of Bengali-speaking Muslims during the claims and objections phase of the ongoing Special Revision (SR) of electoral rolls in Assam. While the Election Commission is conducting SIR exercises in 12 states and Union Territories, Assam is currently undergoing an SR, which is usually meant for routine updates.
Calling the current SR “preliminary”, Sarma said that a full-fledged SIR in Assam would lead to large-scale deletion of Miya voters. He said he was unconcerned about criticism from opposition parties over the issue.
“Let the Congress abuse me as much as they want. My job is to make the Miya people suffer,” Sarma said. He claimed that complaints filed against members of the community were done on his instructions and that he had encouraged BJP workers to keep filing complaints.
“I have told people wherever possible they should fill Form 7 so that they have to run around a little and are troubled,” he said, adding that such actions were meant to send a message that “the Assamese people are still living”.
In remarks that drew further outrage, Sarma urged people to trouble members of the Miya community in everyday life, claiming that “only if they face troubles will they leave Assam”. He also accused the media of sympathising with the community and warned journalists against such coverage.
“So you all should also trouble, and you should not do news that sympathise with them. There will be love jihad in your own house.” He said.
The comments triggered reactions from opposition leaders. Raijor Dal president and MLA Akhil Gogoi said the people of Assam had not elected Sarma to keep one community under constant pressure. Congress leader Aman Wadud accused the chief minister of rendering the Constitution meaningless in the state, saying his remarks showed a complete disregard for constitutional values.
According to the draft electoral rolls published on December 27, Assam currently has 2.51 crore voters. Election officials said 4.78 lakh names were marked as deceased, 5.23 lakh as having shifted, and 53,619 duplicate entries were removed during the revision process. Authorities also claimed that verification had been completed for over 61 lakh households.
On January 25, six opposition parties the Congress, Raijor Dal, Assam Jatiya Parishad, CPI, CPI(M) and CPI(M-L) submitted a memorandum to the state’s chief electoral officer. They alleged widespread legal violations, political interference and selective targeting of genuine voters during the SR exercise, describing it as arbitrary, unlawful and unconstitutional.
