Increased lipid peroxidation in sera of ALS patients: A potential biomarker of disease burden

Background: Markers of oxidative stress and immune activation are significantly elevated in postmortem ALS CNS tissue, although the relevance to pathogenesis is unclear. Objective: To determine the degree and distribution of oxidative stress and immune activation in living ALS patients and whether these levels correlate with the rate of progression or extent of disease. Method: Serum and CSF samples from sporadic ALS (sALS) patients were assayed for 4-hydroxy-2,3-nonenal (HNE), a lipid peroxidation product, and monocyte chemoattractant protein-1α (MCP-1α), a β-chemokine, by high-performance liquid chromatography and ELISA and compared with levels measured in disease and normal control subjects by one-way analysis of variance. SALS serum levels were analyzed in relation to rate of progression, stage of disease, and drug therapy. Results: HNE levels were significantly elevated in the sera and spinal fluid of sALS patients compared with control populations and positively correlated with extent of disease but not rate of progression. MCP-1α levels were also elevated in the sera of sALS patients, with the exception of the neurodegenerative disease control subjects, but decreased with advancing disease. CSF MCP-1α levels were not different between the sampled populations. There was no correlation between serum HNE and MCP-1α levels in sALS patients and extent of disease. However, an inverse relationship between HNE and MCP-1α was demonstrable in vitro. Low levels of HNE stimulated release of MCP-1α from cultured human macrophages, whereas high levels inhibited release of MCP-1α. Conclusions: These data confirm the presence of increased oxidative stress and immune activation in ALS patients. HNE is also suggested as a possible biomarker of disease.