Analysis of smoking and LPO in ALS

Smoking has been suggested as one of the risk factor for amyotrophic lateral sclerosis (ALS) development. In order to investigate whether adverse effects of cigarette smoke in ALS have any association with increase in oxidative stress, disease severity, lipid hydroperoxides (LPO) and superoxide dismutase-1 (SOD1) levels were measured in biofluids of smoker and never smoker ALS patients and clinically correlated. Serum and CSF from sporadic ALS patients (n=50) diagnosed with El Escorial criteria were collected in the study. Serum (n=50) and CSF (n=42) were also collected from normal healthy controls. The LPO levels were estimated using commercially available kits. Enzyme-linked immunosorbent assays (ELISAs) were used to quantitate SOD1. Their levels were further analyzed among smoker and never smoker subjects. Significantly elevated LPO in sera and CSF of ALS patients were observed (p<0.05). There was considerably increased LPO in sera and CSF of smoker ALS subjects matched with disease severity as compared to never smoker ALS (p<0.05). ALS group did not show any alteration in SOD1 when compared to controls (p>0.05). In addition, no change has been observed in SOD1 levels in ALS subjects who smoke (p>0.05). Increased LPO and unaltered SOD1 in ALS patients may suggest the neuro-pathological association of LPO with ALS disease independent of SOD1. With current findings, it may be proposed that LPO levels might constitute as probable biomarker for smoker ALS patients, however, it cannot be concluded without larger gender matched studies. Additional investigations are needed to determine whether LPO upregulation is primary or secondary to motor neuron degeneration in ALS.