Immunohistochemical studies of angiogenin in the skin of patients with amyotrophic lateral sclerosis

Angiogenin (ANG) is a member of the ribonuclease superfamily which is implicated in angiogenesis. ANG maintains normal vasculature and thereby protects motor neurons from various stress conditions. It is suggested that ANG may play a role in pathomechanism of amyotrophic lateral sclerosis (ALS). However, there have been no studies of ANG in ALS skin. We made a quantitative immunohistochemical study of the expression of ANG in the skin from 20 patients with sporadic ALS, 20 patients with other neurologic or muscular disorders (control group A), and 20 patients without neurologic or muscular disorders (control group B). The nuclei of the epidermal cells showed a weak ANG immunoreactivity in ALS patients. These findings became more marked as ALS progressed. The optical density for ANG immunoreactivity of the nucleus in the epidermal cells in ALS patients was significantly lower (p < 0.001) than in control groups A and B. There was a significant negative relationship (r = − 0.82, p < 0.001) between the optical density for ANG immunoreactivity of the nucleus and duration of illness in ALS patients. These data suggest that changes of ANG in ALS skin are related to the disease process and that metabolic alterations of ANG may take place in the skin of ALS patients.