The protein’s levels in ALS patients and controls were measured in blood samples in the study.
The researchers note that the lack of disease markers in ALS, also known as Lou Gehrig’s disease, is holding back progress in the understanding of disease mechanisms and the development of treatments for the disease. They call for a large clinical study to confirm NAIP’s potential as a disease marker and predictive tool.
The study, titled “Neuronal apoptosis inhibitory protein is implicated in amyot rophic lateral sclerosis symptoms,” was published in the journal Scientific Reports.
The study included 18 Japanese patients with ALS and 12 healthy controls. A sample of patients with Parkinson’s disease was also tested to see if the low levels of NAIP seen in ALS patients are specific to ALS, and not common to other neurological disorders. The Parkinson’s patients had similar levels of NAIP in their blood as the healthy control subjects.
NAIP levels and degree of functional impairment were assessed at baseline and every four months for one year. The ALS Functional Rating Scale-Revised (ALSFRS-R) was used to evaluate functional impairment. It is based on physicians’ assessments of patients and can be used periodically to track progression of disease or any response to treatment.
The NAIP level in ALS patients was almost half that of healthy controls. Comparisons of NAIP levels and ALSFRS-R scores showed that a higher amount of NAIP coincided with a smaller change in ALSFRS-R scores at one year. The researchers suggest that continuous increases in NAIP lead to slower disease progression.
“The lack of a reliable biomarker in ALS is hampering the delineation of molecular pathogenesis and the development of therapeutics for ALS,” the researchers wrote.
“These findings implying a role for NAIP as an ALS prognostic biomarker should be braced up by further large scale clinical study. Thus, our present study provides novel insights into the molecular pathogenesis of ALS. The development of strategies targeting the NAIP alteration in ALS patients may be useful as an evaluation and monitoring system for identifying novel ALS therapy,” they added.
“Our present report implies that NAIP will have broad implications for ALS symptoms as a risk factor and a promising prognostic biomarker,” they concluded.