Blood tests can allow a more accurate diagnosis of ALS at an early stage of the disease. As described in a study by researchers from the University of Gothenburg and Umeå University, it involves measuring the blood level of a substance which, as they have also shown, varies in concentration depending on the variant of ALS from which the patient suffers.
The study, published in Scientific reports, include Fani Pujol-Calderón, postdoctoral fellow at Sahlgrenska Academy, University of Gothenburg, and Arvin Behzadi, PhD student at Umeå University and medical intern at Örnsköldsvik Hospital, as shared first authors.
Currently, it is difficult to diagnose amyotrophic lateral sclerosis (ALS), the most common form of motor neuron disease, early in the disease course. Even after prolonged investigation, there is a risk of misdiagnosis due to other illnesses that may resemble ALS in its early stages. Much could be gained from a correct diagnosis earlier, and according to the researchers, the current results look promising.
Neurofilaments, proteins playing a special role in cells and nerve fibers, are the substances of interest. When the nervous system is damaged, neurofilaments leak into the cerebrospinal fluid (CSF) and in lower concentrations into the blood compared to CSF. In their study, scientists from Umeå University and Umeå University Hospital, as well as Gothenburg University and Sahlgrenska University Hospital in Gothenburg, demonstrated that CSF and blood levels neurofilaments can differentiate ALS from other diseases that may resemble early ALS.
More sensitive analytical methods
Compared to several other neurological diseases, previous studies have shown higher concentrations of CSF neurofilaments in ALS. Measuring levels of neurofilaments in blood used to be difficult because they occur at much lower concentrations compared to CSF. In recent years, however, new, more sensitive methods of analysis have created new possibilities for doing so.
The current study shows a strong association, in patients with ALS, between the amount of neurofilaments in the blood and in the CSF. The study is based on blood and CSF samples taken from 287 patients who had been referred to the Department of Neurology at Umeå University Hospital for investigation of possible motor neuron disease. After a thorough investigation, 234 of these patients were diagnosed with ALS. These had significantly higher levels of neurofilaments in CSF and blood compared to patients who had not been diagnosed with ALS.
Differences between various ALS subgroups were also studied and detected. Patients whose disease symptoms began in the head and neck region had higher blood neurofilament concentrations and poorer survival than patients whose disease began in an arm or leg. The study was also able to quantify differences in blood levels of neurofilaments and survival for the two most common mutations associated with ALS.
“Discovering suspected cases of ALS by blood test opens up entirely new opportunities for the screening and measurement of neurofilaments in longitudinally drawn blood, allowing easier quantification of treatment effects in clinical drug trials compared to to longitudinal CSF collection. Detecting ALS early in the course of the disease can facilitate early administration of pharmaceutical treatment, before the muscles atrophy,” says Arvin Behzadi.
ALS is a neurodegenerative syndrome that results in the loss of nerve cells in the brain and spinal cord, leading to muscle weakness and atrophy. Most of these patients die within two to four years of the onset of symptoms, but about one in ten survive more than ten years after the first symptoms appear. Several genetic mutations have been linked to ALS. Currently, there is no curative treatment. Nevertheless, the currently available drug has been shown to prolong the survival of some ALS patients if given in time.
Source of the story:
Material provided by University of Gothenburg. Note: Content may be edited for style and length.