Pathology of the inferior olivary nucleus in patients with multiple system atrophy.

The inferior olivary nucleus (ION) from nine patients with multiple system atrophy was examined with antibodies against alpha-synuclein, ubiquitin, synaptophysin, glial fibrillary acidic protein, the Golgi apparatus (GA)-trans-Golgi network (TGN), and microglia/macrophages. As previously reported, there were neuronal loss, gliosis, and alpha-synuclein-positive cytoplasmic inclusions in neurons and glia. In addition, all neurons with alpha-synuclein-positive cytoplasmic inclusions contained abnormal profiles of the GA and TGN, which were reduced in size and numbers. This finding suggests a relationship between the pathogenetic mechanisms causing inclusion body formation and abnormalities of the GA-TGN. This study is also consistent with the conclusion that lesions of the ION may not always reflect changes of transsynaptic degeneration secondary to Purkinje cell loss.