LAUSR

ABSTRACT Objective: Amyotrophic lateral sclerosis (ALS) is a progressive and fatal motor neuron disease. Hypoxic stress is suspected as the pathogenesis of ALS, however, no positron emission tomography (PET) study for hypoxic stress has been conducted in the spinal cord of ALS patients. Methods: In the present study, we examined cervical spinal hypoxic stress of nineALS patients with upper extremity (U/E) atrophy by18F-fluoromisonidazole (FMISO) PET. Results: On the ipsilateral side of C1 and C5 levels, 18F-FMISO uptake increased significantly compared with the contralateral side (*p < 0.05) and the control subject (**p < 0.01). In addition, a strong correlation was found between 18F-FMISO uptake of the C5 level and the rate of progression of the ALS FRS-R score (R = 0.781, *p = 0.013). Conclusion: These results indicate that hypoxic stress increased in the spinal cord of ALS patients with a close link to ALS progression. Both hypoxic stress and a compromised response to hypoxia, which may lead to subsequent motor neuron death, could be a potential therapeutic target for ALS.