Researchers believe that they may have found the cause of myasthenia gravis (MG), according to an article in Myasthenia Gravis News. A study found that issues with mitophagy in immune cells could be the root of MG, and it also identified an antibiotic that could be a treatment.
About Myasthenia Gravis (MG)
Myasthenia gravis (MG) is the most common autoimmune neuromuscular disorder. Those affected experience weakness in the voluntarily controlled muscles. Physical activity worsens the symptoms, whereas periods of rest can improve them. Throughout the world, about 20 of every 100,000 people have MG. It is an autoimmune condition, meaning the body attacks itself, specifically the proteins that are necessary for communication between the brain and muscles. This causes symptoms like drooping eyelids, issues with chewing and swallowing, fatigue and weakness in the skeletal muscles, slurred speech, double vision, and a changed gait. For a small percentage of those with MG, weakness in the chest could lead to life-threatening respiratory issues.
Doctors diagnose this condition through a physical exam, evaluation of patient history, blood tests, and EMGs. Like many rare disorders, a diagnosis is not always easy to obtain. The similarity of symptoms to other conditions often results in a misdiagnosis. After doctors have confirmed that one has MG, treatment consists of steroids, plasmapheresis, or surgery to remove the thymus gland. While there is no cure, some medications can greatly improve symptoms or even induce remission.
The Cause of MG
Researchers at the Hubei University of Medicine in China have identified mitophagy, a form of autophagy, as a possible cause of MG. They found that issues with this process lead to the malfunction and death of T-cells. These cells are needed to control the activity of other immune cells, so when they are damaged, the entire immune system is affected.
They did so by utilizing blood samples from 30 participants, 15 with MG and 15 healthy. Using two pharmacological agents, rapamycin and 3-methyladenine, researchers were able to promote and block mitophagy. Flow cytometry was then utilized to assess mitochondrial function and regulatory T-cell’s function.
Results showed that mitophagy levels were lower in patient-derived regulatory T-cells when compared to the healthy control group. Additionally, rapamycin led to heightened mitophagy levels. Further investigation revealed that MG patients had mitochondria with lower membrane potential, but fortunately could be improved with rapamycin.
More research needs to be done in order to better understand this process and rapamycin’s effects on cells, but researchers are very excited by these findings.
