INSULIN-LIKE AND FIBROBLAST GROWTH-FACTORS IN SPINAL-CORDS, NERVE ROOTS AND SKELETAL-MUSCLE OF HUMAN CONTROLS AND PATIENTS WITH AMYOTROPHIC-LATERAL-SCLEROSIS

Insulin-like growth factors (IGF-I and IGF-II) and fibroblast growth f actors [acidic FGF (aFGF) and basic FGF (bFGF)] are trophic for motor neurones in vitro and (in laboratory animals) in vivo. An immunohistoc hemical investigation was performed on the distribution of these facto rs in the neuromuscular system of control patients and patients with a myotrophic lateral sclerosis (ALS). Comparisons were made with rat tis sue. IGF-I immunoreactivity (IGF-1-IR) was seen in motor neurone cell bodies and axons, astroglia and Schwann cells, and in muscle fibres. I GF-II-IR was weak in all these cells. aFGF-IR was present in motor neu rone cell bodies and axons, oligodendroglia and muscle fibres, but was not demonstrable in Schwann cells. bFGF-IR was present in motor neuro ne cell bodies and axons, and in astroglia, but was not seen in Schwan n cells or muscle fibres. The distribution of the IGFs and FGFs in mat erial from motor neurone disease (MND) and controls was similar. A rol e for any of these factors in the etiology of MND is, therefore, unlik ely. IGF-1-IR and aFGF-IR were stronger in type II than in type I musc le fibres and were increased in denervated fibres. Species differences were found for IGF-I and bFGE The function of these factors is appare ntly not entirely similar in humans and rats.