Researchers at the Federal University of São Carlos (UFSCar) in Sorocaba (state of São Paulo, Brazil) have developed a technique to diagnose early-stage multiple sclerosis and distinguish it from neuromyelitis optica.
The immune system of a person with these diseases produces antibodies that attack and damage part of the myelin sheath, an insulating layer that protects nerves, including those in the brain and spinal cord, and aids the transmission of electrical impulses. Permanent lesions form in brain regions over time.
Using a nanobiosensor originally developed to detect herbicides, heavy metals and other pollutants, the UFSCar group created a method for observing myelin basic protein (MBP) peptides interacting with antibodies in samples from patients under an atomic force microscope (AFM), a media release from Fundação de Amparo à Pesquisa do Estado de São Paulo explains.
“Atomic force spectroscopy can detect the presence of specific antibodies for each of these two diseases in cerebrospinal fluid and blood serum. If the antibodies are attracted by the peptides deposited on the sensor during the test, this is a sign that the patient has the disease. The device is highly sensitive and can detect a small amount of antibodies, so the method can diagnose the disease at an early stage,” says Fabio de Lima Leite, a researcher in UFSCar’s Science and Technology for Sustainability Center and last author of an article on the method published in UltraMicroscopy.
In the study, the researchers used serum and cerebrospinal fluid from patients who were at different stages of multiple sclerosis and receiving treatment at the hospital run by São Paulo State University’s Botucatu Medical School (FMB-UNESP) under the responsibility of Doralina Guimarães Brum, a researcher at the school, and Paulo Diniz da Gama, a neurologist affiliated with the Pontifical Catholic University of São Paulo (PUC-SP) in Sorocaba.
“The cerebrospinal fluid and serum were purified, leaving only antibodies in each sample. This enabled us to detect specific antibodies for multiple sclerosis, such as anti-MBP 85-99. If these antibodies are circulating in a patient, they probably have multiple sclerosis. Our next step in the study is to produce a sensor that doesn’t require purified samples,” Leite says, the release continues.
In another study published recently in Scientific Reports, UFSCar researchers identified patients with neuromyelitis optica and distinguished them from patients with multiple sclerosis.
“A biomarker for the disease exists, so it was possible to detect the anti-aquaporin 4 antibody in patient samples by the same method as that used to detect multiple sclerosis,” says Ariana de Souza Moraes, a researcher at UFSCar and a coauthor of the article.
Neuromyelitis optica can currently be diagnosed by ELISA (enzyme-linked immunosorbent assay), a widely available method that is inexpensive and hence affordable for most patients.
“However, this method isn’t as sensitive as the nanoimmunosensor and can’t detect the disease in its early stages,” Moraes adds.
Another advantage of the sensor is that it can distinguish the two diseases, avoiding a common diagnostic error.
“The two disorders have similar symptoms but different action mechanisms and treatments,” Moraes comments.
“An immunomodulator is recommended for one and an immunosuppressant for the other. An incorrect diagnosis can aggravate the disease. If a patient with neuromyelitis optica is treated for multiple sclerosis, optic nerve inflammation is accelerated and can’t be reversed. The sensor is expected to represent a major advance for patients with demyelinating disorders.”
[Source(s): Fundação de Amparo à Pesquisa do Estado de São Paulo, EurekAlert]