Understanding a rare disease is the first step in treating it. How can you combat the underlying mechanisms of a disorder if you do not know what they are? A team of medical professionals is trying to do just this in regard to myasthenia gravis (MG), a rare neuromuscular disorder.
They have created a cellular model of the neuromuscular junction (NMJ), which will provide a better comprehension of neuromuscular diseases as a whole. Their hope is to use this model to aid in the diagnosis and development of treatments for MG. You can read their complete research here, where it was published in Biomaterials.
About Myasthenia Gravis
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.
About the New Model
Because we are in desperate need of new therapies for neuromuscular disorders, this recent innovation is very exciting for doctors and patients alike.
Before we can understand why it is such a positive, we must first understand what the NMJ is. Like the name suggests, it is where the neurons come into contact with the muscle cells. Messages from the brain to the muscles must pass through this junction.
In those with MG, the immune system attacks parts of the NMJ. Specifically, self-reactive antibodies target proteins necessary for communication between the brain and muscles. Medical professionals have used animal models to illustrate this process and MG in the past, but these models have missed some important components that are only present in humans.
In order to solve this problem, the researchers took human nerve and muscle cells and utilized them so that they mimic a human NMJ. After the model was created, optogenetics was used to study it. The researchers programmed it so that the neurons would send signals to the muscle cells after being exposed to blue light. All of these interactions were recorded so that they could be further analyzed.
They then exposed the model to serum (the noncellular part of blood) of MG patients. The antibodies within the serum blocked communication between the neurons and muscles, just as they do within human MG patients. This result was very positive, as it means that this model could be used in MG research in the future, whether that is for diagnosis or treatments.
In the end, this model will be extremely useful for research purposes, not just for MG, but for a number of neuromuscular disorders.
You can find the source article here.
