Plasma cardiac troponin T complements neurofilament light chain by reflecting disease phase and phenotypic variation in amyotrophic lateral sclerosis

BACKGROUND: Neurofilament light chain (NfL) is an established marker of neuronal injury and disease aggressiveness in amyotrophic lateral sclerosis (ALS). In contrast, the clinical and biological significance of cardiac troponin T (cTnT) in ALS is not fully understood. We aimed to evaluate the relationship between plasma cTnT and disease aggressiveness, progression stage, and clinical phenotype in comparison with NfL. METHODS: Plasma cTnT and cerebrospinal fluid (CSF) NfL were analysed at diagnosis in a population-based cohort of 526 patients with ALS. Disease aggressiveness was modelled using the D50 framework, which quantifies the time taken to lose 50% of functional capacity (ALSFRS-R) and normalises individual disease trajectories. Biomarker associations with disease aggressiveness, phase, and clinical variables were assessed through group comparisons, logistic and linear regression, and receiver operating characteristic analyses. RESULTS: Neurofilament light chain in CSF was strongly associated with disease aggressiveness, with higher levels in patients with more aggressive disease. In contrast, plasma hs-cTnT did not correlate with D50. Across disease phases, CSF NfL remained relatively stable, whereas plasma hs-cTnT increased with advancing rD50, suggesting accumulation with disease progression. Plasma hs-cTnT levels were higher in patients with spinal compared to bulbar onset. Combined biomarker models improved sensitivity and negative predictive value for identifying less aggressive disease. CONCLUSION: Plasma hs-cTnT and CSF NfL capture distinct but complementary dimensions of ALS pathology. While NfL reflects disease aggressiveness, hs-cTnT aligns with disease phase and clinical phenotype, supporting its use as a complementary biomarker for ALS characterisation and monitoring.