Postganglionic sudomotor denervation in patients with multiple system atrophy

Area of Science:

• Neurology
• Autonomic Neuroscience
• Pathology

Background:

• Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic dysfunction.
• The precise mechanisms underlying dysautonomia in MSA, particularly the involvement of peripheral autonomic nerves, require further elucidation.

Purpose of the Study:

• To investigate postganglionic autonomic nervous system involvement in multiple system atrophy (MSA).
• To quantify sudomotor innervation in skin biopsies of MSA patients and compare it with healthy controls.

Main Methods:

• Skin biopsies were obtained from the thigh, leg, and fingertip of 29 MSA patients and 29 healthy controls.
• Sudomotor innervation was assessed using immunofluorescence and morphometric analysis of nerve density.
• Autonomic symptoms were evaluated using the SCOPA-AUT questionnaire and sudomotor function by the silastic imprint test.

Main Results:

• Sudomotor nerve density was significantly lower in MSA patients compared to controls across all examined skin sites (fingertip, thigh, and leg).
• Measurements of nerve density showed good correlation with unbiased stereologic methods.
• A trend towards lower sudomotor function and higher dysautonomic complaints was observed in MSA patients.

Conclusions:

• The findings support the hypothesis of postganglionic autonomic impairment in MSA.
• This peripheral nerve involvement, alongside central degeneration, likely contributes to the development of dysautonomic disorders in MSA.