PROCEEDINGS OF THE XXI CONGRESS OF THE ITALIAN ASSOCIATION OF MYOLOGY: Digital EditionDecember 01-04, 2021 Neurofilament light chain and Profilin-1 in adult SMA patients under nusinersen treatment: 26-months follow-up

As an update of our study in 30 adult SMA type 3 patients we tested as potential biomarkers Neurofilament light chain (NfL) and Profilin-1 (PFN-1) during a 26 months follow-up (timepoint M6). PFN-1 is a small actin-binding protein required in both the presynaptic and the postsynaptic compartment with a role in regulating cytoskeletal architecture and dynamics of neurons (Witke, 2004). CSF NfL was tested with an enzyme-linked immunosorbent assay (ELISA) kit (UmanDiagnostics, Sweden). PFN-1 was measured with a commercial manual ELISA kit (Cusabio, China) in CSF samples of 6 patients (3 sitters 3 walkers) at time points L1, L3 and M2 and in every available serum sample from time point L1 to time point M6; 19 serum samples of healthy donors as a control group. Mean NfL at M6 was 381.83 ± 455.71 ng/l, slightly higher than baseline but not significantly different from M3. PFN-1 concentration in all 18 CSF samples was below the lower limit of quantification (< 31.25 ng/l). Serum PFN-1 at baseline was higher in SMA group than in healthy controls (mean 1016 vs 608 ng/l, p = 0.001 Student’s t test). PFN-1 showed a complex dynamic during loading phase, with a significant reduction at L4 compared to baseline. No correlation was found with NfL and motor scores at each time point. PFN-1 as an exploratory cytoskeletal biomarker changed significantly during the first two months of treatment. To our knowledge this is the first report of PFN-1 determination in serum of SMA patients.