RIMMED VACUOLES WITH BETA-AMYLOID AND UBIQUITINATED FILAMENTOUS DEPOSITS IN THE MUSCLES OF PATIENTS WITH LONG-STANDING DENERVATION (POSTPOLIOMYELITIS MUSCULAR-ATROPHY) - SIMILARITIES WITH INCLUSION-BODY MYOSITIS

In the chronically denervated muscles of patients with prior paralytic poliomyelitis, there are secondary myopathic features, including endo mysial inflammation and rare vacuolated fibers. To assess the frequenc y and characteristics of the vacuoles and their similarities with thos e seen in inclusion body myositis (IBM), we examined 58 muscle biopsy specimens from patients with prior paralytic poliomyelitis for (1) the presence of rimmed vacuoles; (2) acid-phosphatase reactivity; (3) Con go-red-positive amyloid deposits; (4) electron microscopy, searching f or tubulofilaments; and (5) immunoelectron microscopy, using antibodie s against beta-amyloid and ubiquitin. We found vacuolated muscle fiber s in 18 of 58 (31%) biopsies, with a mean frequency of 2.06 +/- 0.42 f ibers per specimen. The vacuoles contained acid phosphatase-positive m aterial in 6 of the 18 (33.30%) specimens and stained positive for Con go red in five (27.80%). By immunoelectron microscopy, the vacuoles co ntained 5.17 +/- 0.13 nm fibrils and 14.9 +/- 0.31 nm filaments that i mmunoreacted with antibodies to beta-amyloid and ubiquitin in a patter n identical to the one seen in IBM. We conclude that vacuolated muscle fibers containing filamentous inclusions positive for amyloid and ubi quitin are not unique to IBM and the other vacuolar myopathies but can also occur in a chronic neurogenic condition, such as postpoliomyelit is. The chronicity of the underlying disease, rather than the cause, m ay lead to vacuolar formation, amyloid deposition, and accumulation of ubiquitinated filaments. Copyright (C) 1998 by W.B. Saunders Company.