Brain: amazing! Complement system disorder even participate in multiple sclerosis resulting in vision loss!

November 4, 2019 / Biovalley / recently, according to a study from Johns Hopkins University School of medicine, scientists have identified three so-called "complement system" genes, which seem to play a role in MS induced vision loss By analyzing the DNA of multiple sclerosis (MS) patients and using high-tech retinal scanning technology, the researchers finally screened out the pathogenic genes If the findings are confirmed by subsequent studies, they could serve as indicators for monitoring and predicting MS progress and severity, the researchers said In MS, over time, neurocommunication between the brain and the rest of the body is disrupted, leading to chronic and / or intermittent muscle spasms, tremors, imbalances, pain, numbness, depression, loss of bladder or bowel control and vision problems MS is more common in women, and symptoms vary widely (image source: www Pixabay Com) "although we can provide treatment for sudden onset of multiple sclerosis, we have no way to prevent the occurrence and deterioration of progressive multiple sclerosis", by Peter, Professor of Neurology and neuroscience, Johns Hopkins University School of Medicine Dr Calabresi said: "we believe that our research has opened up a new research route for complement gene, which is a potential method to treat disease progress and nerve cell death." In their study, the researchers used optical coherence tomography to look at the back of the eyes of patients and to assess the extent of retinal nerve cell damage in 374 patients with various Ms The average age of the patients was 43 years old, most of them were female (78%) The researchers recruited and imaged these patients every few years from 2010 to 2017, with an average of 4.6 scans per participant during the study Scanning is used to measure the thinning of the layer of nerve cells (called ganglion cells) in the retina over time The results showed that in terms of average deterioration rate, each patient lost 0.32 μ m per year The researchers then used blood samples from patients to collect their DNA and looked for mutations in the subgroup with the fastest degradation rate, identifying 23 DNA variants related to the complement gene C3 Next, in order to find out the genes related to vision loss, they conducted an existing clinical trial group analysis of another 835 MS patients, 74% of whom were women, with an average age of 40 years Each participant received a contrast test about their ability to distinguish each year The test requires people to read five consecutive lines of letters and use a separate vision chart with low contrast letters to simulate the visual effect in low light (dusk or darkness) From top to bottom, the subtitles in each line of the alphabet will get darker and darker Using DNA from blood samples from the 835 participants, the researchers identified specific genetic changes in two complement genes, C1qA and CR1 Among them, patients with genetic change of C1qA gene are 71% more likely to have difficulty in visual contrast recognition than those with normal population, while those with genetic change of CR1 gene are 40% more likely to have difficulty in visual contrast recognition Therefore, these complement genes were found to be related to the severity of vision loss caused by MS "Traditionally, complement proteins are thought to be part of the immune system by binding to antibodies and helping kill infected cells in the body," the authors said Ten years ago, however, other researchers found that complement proteins bind to connections between neurons and help them grow in specific directions Too much complement can damage nerve cells and cause them to die " "Our next step will be to repeat these studies in a larger population," said Kathryn Fitzgerald, first author and assistant professor of Neurology at Johns Hopkins University School of medicine Animal studies are also needed to reveal the function of complement proteins, so that we can find out the mechanism behind their role in killing neurons in MS patients and design targeted therapies " Sources of information: potential genetic markers of multiple sciences severity original sources: Kathryn C Fitzgerald, kitchen Kim, Matthew D Smith, Sean a Aston, Nicholas Fioravante, Alissa m Rothman, Stephen Krieger, stage s cofield, dorlan J kimbrough, pavan Bhargava, SHIV saidha, Katharine a whartenby, ARI J green, Ellen m Mowry, Gary r cutter, Fred D Lublin, Sergio E Baranzini, Philip L De Jager, Peter A Calabresi Early complement genes are associated with visual system degeneration in multiple sclerosis Brain , 2019; 142 (9): 2722 DOI: 10.1093/brain/awz188