1. Association of innervation-adjusted alpha-synuclein in arrector pili muscles with cardiac noradrenergic deficiency in autonomic synucleinopathies.
- Author
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Isonaka R, Gibbons CH, Wang N, Freeman R, and Goldstein DS
- Subjects
- Aged, Biopsy, Female, Heart Ventricles diagnostic imaging, Humans, Male, Multiple System Atrophy diagnosis, Positron-Emission Tomography methods, Shy-Drager Syndrome diagnosis, Skin innervation, Muscle, Smooth innervation, Sympathetic Fibers, Postganglionic pathology, Synucleinopathies diagnosis, alpha-Synuclein analysis
- Abstract
Background: Autonomic synucleinopathies feature deposition of the protein alpha-synuclein (AS) in neurons [e.g., Lewy body neurogenic orthostatic hypotension (nOH)] or glial cells (multiple system atrophy, MSA). AS in skin biopsies might provide biomarkers of these diseases; however, this approach would be complicated or invalidated if there were substantial loss of AS-containing nerves. We report AS content in arrector pili muscles in skin biopsies after adjustment for local innervation in patients with Lewy body nOH or MSA. Cardiac sympathetic neuroimaging by myocardial
18 F-dopamine positron emission tomography (PET) was done to examine pathophysiological correlates of innervation-adjusted AS., Methods: Thirty-one patients (19 Lewy body nOH, 12 MSA) underwent thoracic18 F-dopamine PET and skin biopsies. AS signal intensity analyzed by immunofluorescence microscopy was adjusted for innervation by the ratio of AS to protein gene product (PGP) 9.5, a pan-axonal marker (Harvard lab site), or the ratio of AS to tyrosine hydroxylase (TH), an indicator of catecholaminergic neurons (NIH lab site)., Results: The Lewy body nOH group had higher ratios of AS/PGP 9.5 or log AS/TH than did the MSA group (0.89 ± 0.05 vs. 0.66 ± 0.04, -0.13 ± 0.05 vs. -1.60 ± 0.33; p < 0.00001 each). All 19 Lewy body patients had AS/PGP 9.5 > 0.8 or log AS/TH > 1.2 and had myocardial18 F-dopamine-derived radioactivity < 6000 nCi-kg/cc-mCi, the lower limit of normal. Two MSA patients (17%) had increased AS/PGP or log AS/TH, and two (17%) had low18 F-dopamine-derived radioactivity., Conclusions: Lewy body forms of nOH are associated with increased innervation-adjusted AS in arrector pili muscles and neuroimaging evidence of myocardial noradrenergic deficiency.- Published
- 2019
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