Postganglionic sudomotor denervation in patients with multiple system atrophy

To evaluate postganglionic autonomic involvement in multiple system atrophy (MSA).

We quantified sudomotor innervation in skin biopsy of 29 patients with MSA (19 male and 10 female; age 60.0 ± 7.7 years) and 29 age- and sex-matched healthy subjects. Samples were obtained from thigh and leg and, in 20 out of the 29 cases, also from fingertip. Dysautonomic complaints were evaluated by SCOPA-AUT, a self-administered questionnaire. Sudomotor function was evaluated in a subgroup of patients by the silastic imprint test. Skin samples were processed by indirect immunofluorescence using pan-neuronal and selective cholinergic markers. Total length of sudomotor nerves was measured on digital confocal images using a semiautomated morphometric approach.

Measurements of sudomotor nerve density (total length of nerve per volume of glandular tissue) favorably correlated to values obtained using a stereologic unbiased method. Sudomotor nerve density was lower in patients compared to controls in all the examined sites (0.9 ± 0.2 vs 1.9 ± 0.4 nm/μm(3), p < 0.001, in fingertip; 0.7 ± 0.2 vs 1.9 ± 0.5 nm/µm(3), p < 0.001, in thigh; 0.6 ± 0.2 vs 1.8 ± 0.4 nm/µm(3), p < 0.001, in leg).

Our data support the hypothesis that postganglionic impairment occurs in MSA and may contribute with the coexisting degeneration of central structures to the development of dysautonomic disorders in this condition.