Increased expression of insulin-like growth factor I in skin in amyotrophic lateral sclerosis

OBJECTIVES Insulin-like growth factor I (IGF-I) has potent effects on motor neuron survival and is being studied as a possible therapeutic agent for ALS. However, little is known concerning IGF-I in the skin of patients with amyotrophic lateral sclerosis (ALS). The aim was to evaluate IGF-I immunoreactivity of skin in patients with ALS. METHODS IGF-I immunoreactivity of skin from 18 patients with ALS and 16 controls was examined. RESULTS IGF-I immunoreactivity was markedly positive in the epidermis and dermal blood vessels and glands and was moderately positive in the reticular dermis in all patients with ALS. On the other hand, the epidermis and dermal blood vessels and glands and the reticular dermis showed a weak IGF-I immunoreactivity in controls. The optical density for IGF-I immunoreactivity of the epidermis and dermal blood vessels and glands, and the reticular dermis in patients with ALS was significantly higher than in diseased controls, and was significantly increased with duration of illness. CONCLUSIONS These data suggest that a metabolic alteration of IGF-I may take place in the skin of patients with ALS.