Circulating Serum Cell-Free Mitochondrial DNA in Amyotrophic Lateral Sclerosis

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Mitochondrial dysfunction is a known hallmark of amyotrophic lateral sclerosis (ALS).
• The utility of circulating cell-free mitochondrial DNA (Cf-mtDNA) as a biomarker in ALS is not well-established.
• Previous studies have yielded conflicting results regarding Cf-mtDNA levels in ALS patients.

Purpose of the Study:

• To investigate serum Cf-mtDNA levels in ALS patients compared to healthy controls.
• To explore associations between Cf-mtDNA levels and disease biomarkers, clinical progression, and survival in ALS.
• To determine the diagnostic and prognostic potential of Cf-mtDNA in ALS.

Main Methods:

• A case-control study was conducted with 54 ALS patients and 36 healthy controls.
• Serum Cf-mtDNA levels were quantified using quantitative droplet digital PCR.
• Correlations with clinical features, neurofilaments, inflammatory indices, and survival were analyzed.

Main Results:

• Average serum Cf-mtDNA levels did not significantly differ between ALS patients and healthy controls (p = 0.308).
• Receiver operating characteristic (ROC) analysis showed limited discriminant ability (AUC = 0.595).
• Cf-mtDNA levels showed an inverse correlation with serum creatinine (p = 0.018) but no significant associations with other clinical parameters or survival.

Conclusions:

• Serum Cf-mtDNA does not appear to be a reliable standalone diagnostic or prognostic biomarker for amyotrophic lateral sclerosis in this cohort.
• Discrepancies with prior research may be due to methodological differences, cohort composition, or genetic heterogeneity.
• Further large-scale, longitudinal studies with genetic stratification are needed to clarify the role of Cf-mtDNA in ALS pathophysiology.