Affiliations: [a] Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| [b] Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| [c] Assistive Technology Department, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| [d] Department of Biological Chemistry & Pharmacology, The Ohio State University, Columbus, OH, USA
Correspondence to: Stephen J. Kolb, MD, PhD (SJK), Rightmire Hall, Rm 226A, 1060 Carmack Road, Columbus, OH 43210, USA. Tel.: +1 614 292 3545; Fax: +1 614 292 4118; E-mail: [email protected].
Abstract: Objective:To retrospectively evaluate the utility of serum and cerebrospinal fluid (CSF) levels of neurofilament light chain (NfL) and phosphorylated neurofilament heavy chain (pNfH) as biomarkers for spinal muscular atrophy (SMA) progression and response to nusinersen treatment. Methods:NfL and pNfH levels were quantified using single molecular array (SIMOA) in CSF of 33 adult SMA patients (SMN copy number 3–5) before and in response to nusinersen treatment. In 11 of the patients, blood serum samples were also collected. CSF NfL and pNfH from patients were compared to CSF Nfs from age-matched controls without neurological disease (n = 6). For patients, pearson correlation coefficients (r) were calculated to investigate associations between Nf levels and other functional outcome measures. Results:Nf levels were similar between SMA and control adults and showed no change in response to nusinersen treatment in CSF or serum. Cross-sectional analyses showed an increase in CSF NfL and pNfH with age in patients (NfL p = 0.0013; pNfH p = 0.0035) and an increase in CSF NfL in controls (p = 0.002). In non-ambulatory patients, baseline serum pNfH showed a negative correlation with multiple strength and functional assessment metrics including Revised Upper Limb Module (r = –0.822, p = 0.04), upper extremity strength (r = –0.828, p = 0.042), lower extremity strength (r = –0.860, p = 0.028), and total strength (r = –0.870, p = 0.024). Conclusions:Nf levels did not change in response to nusinersen in adults with SMA and were not different from controls. In patients and controls, we detected an age-related increase in baseline CSF NfL and pNfH levels. Though some associations were identified, our results suggest Nf levels are not preditive or prognostic biomarkers in this population.