Lou Gehrig’s disease, the common name for amyotrophic lateral sclerosis (ALS), is caused by nerve degeneration resulting in loss of voluntary control over muscle movement. But in its early stages, it can be easily confused with other ailments with similar symptoms.
“The disease has to progress far enough so that the patient begins to experience significant muscle weakness, so that a physician can identify the problem,” said James Connor, distinguished professor and vice chair of neurosurgery at Penn State University at Hershey. “If we had a biomarker, we could start treatments earlier and perhaps save more nerve cells and slow the disease.”
Connor, together with colleagues at the Hershey Medical Center, zeroed in on the smallest inflammation-related proteins in the spinal fluid. They reasoned that this should be their focus because the disease is associated with nerve-cell inflammation and because small proteins are likely to be missed in large-scale protein studies.
The research team studied two groups of patients – one of 41 people with ALS, and a second of 31 who merely complained of muscle problems, such as weakness and cramps. The scientists drew spinal fluid samples and tested them for inflammation-linked proteins.
“We found a set of 11 proteins that were significantly higher in the spinal fluid of ALS patients,” said Connor. “Two proteins were significantly higher in the control group, suggesting that ALS is associated with an increase in some proteins, and a decrease in other proteins.”
Armed with the protein assay, the research team was able to accurately identify spinal fluid from ALS patients 92 percent of the time. The team concluded that ALS is an inflammatory disease of the spinal cord, and that therefore therapy should be targeted at that site, instead of treating cells throughout the body and hoping for a benefit to the brain and spinal cord.
The protein markers, Connor said, could help save time otherwise lost in diagnosing ALS. For instance, a person with leg or grip-strength weakness could be tested for the biomarkers. If the test shows possible ALS, treatment could continue.