Multi-organ distribution of phosphorylated alpha-synuclein histopathology in subjects with Lewy body disorders

Abstract

A sensitive immunohistochemical method for phosphorylated alpha-synuclein was used to stain sets of sections of spinal cord and tissue from 41 different sites in the bodies of 92 subjects, including 23 normal elderly, 7 with incidental Lewy body disease (ILBD), 17 with Parkinson's disease (PD), 9 with dementia with Lewy bodies (DLB), 19 with Alzheimer's disease with Lewy bodies (ADLB) and 17 with Alzheimer's disease with no Lewy bodies (ADNLB). The relative densities and frequencies of occurrence of phosphorylated alpha-synuclein histopathology (PASH) were tabulated and correlated with diagnostic category. The greatest densities and frequencies of PASH occurred in the spinal cord, followed by the paraspinal sympathetic ganglia, the vagus nerve, the gastrointestinal tract and endocrine organs. The frequency of PASH within other organs and tissue types was much lower. Spinal cord and peripheral PASH was most common in subjects with PD and DLB, where it appears likely that it is universally widespread. Subjects with ILBD had lesser densities of PASH within all regions, but had frequent involvement of the spinal cord and paraspinal sympathetic ganglia, with less-frequent involvement of end-organs. Subjects with ADLB had infrequent involvement of the spinal cord and paraspinal sympathetic ganglia with rare involvement of end-organs. Within the gastrointestinal tract, there was a rostrocaudal gradient of decreasing PASH frequency and density, with the lower esophagus and submandibular gland having the greatest involvement and the colon and rectum the lowest.

Fig. 1

Photomicrographs of slides of immunohistochemical staining for phosphorylated α-synuclein histopathology (PASH) in paraffin sections of the spinal cord, sympathetic ganglia and vagus nerve. Positive staining is black, the counterstain is neutral red. a The intermediolateral horn of the thoracic spinal cord of a subject with PD, showing immunoreactive fibers, puncta and perikaryal cytoplasmic inclusions. Calibration bar 80 µm. b, c Low and higher magnification images of the posterior root entry into the sacral spinal cord of a subject with DLB, showing immunoreactive neuronal perikaryal staining. Calibration bar in b 0.3 mm; in c 80 µm. d, e Low and higher magnification images of the anterior horn of the sacral spinal cord in a subject with PD, showing diffuse cytoplasmic perikaryal immunoreactivity of a large motorneuron. Calibration bar in d 0.5 mm; in e 60 µm. f Sacral spinal cord adjacent to the central canal of a subject with PD, showing immunoreactive swollen degenerating neurons or neurites. Calibration bar 80 µm. g, h Low and higher magnification images of a middle cervical sympathetic ganglion of a subject with DLB, showing frequent immunoreactive dystrophic neurites, puncta and neuronal perikaryal cytoplasmic inclusions. Calibration bar in g 0.1 mm; calibration bar in h 100 µm. i Small branch of the vagus nerve in a subject with PD, showing several immunoreactive nerve fibers. Calibration bar 60 µm

Fig. 2

Photomicrographs of immunohistochemical staining for phosphorylated α-synuclein in paraffin sections of bodily organs and tissue. Positive staining is black, the counterstain is neutral red. a, b Low and higher magnification images of the submandibular gland in two subjects with PD, showing immunoreactive nerve fibers within the stroma of the gland. Calibration bar in a 0.2 mm; in b 100 µm. c The submucosa of the lower esophagus of a subject with PD, showing immunoreactive puncta, fibers and perikaryal cytoplasmic inclusions in ganglion cells. d Immunostaining of fibers in the duodenal submucosa of a subjects with DLB. Calibration bar 20 µm. e A single immunoreactive fiber in the stroma of the pancreas from a subject with PD. Calibration bar 40 µm. f A single immunoreactive fiber in the submucosa of a primary bronchus of a subject with PD. Calibration bar 40 µm. g A few immunoreactive fibers in the submucosa of the larynx of a subject with PD. Calibration bar 20 µm. h Several immunoreactive fibers in an epicardial nerve twig entering the myocardium in a subject with DLB. Calibration bar 100 µm. i A single immunoreactive fiber in the intermyenteric plexus of the urinary bladder of a subject with DLB. Calibration bar 20 µm. j Frequent immunoreactive fibers, puncta as well as cells with diffusely stained perikaryal cytoplasm in the adrenal medulla of a subject with PD. Calibration bar 100 µm. k A single immunoreactive fiber in the stroma of the parathyroid gland of a subject with PD. Calibration bar 10 µm. l The ovary of a woman with PD showing diffuse perikaryal immunostaining of a neuron-like cell with adjacent immunoreactive fibers and puncta. Calibration bar 10 µm

Fig. 3

Photomicrographs of immunohistochemical staining for phosphorylated α-synuclein in 80-µm thick frozen sections of formalin-fixed, cryoprotected tissue blocks of submandibular gland and lower esophagus. Positive staining is black. There is no counterstain. Submandibular gland from subjects with DLB (a–c) and PD (d) showing frequent immunoreactive fibers in the gland parenchyma (a), stroma (b) and around a small artery (d), while frequent immunoreactive puncta are seen in c. Lower esophagus from subjects with PD (e, g, h) and DLB (f) showing immunoreactive nerve fibers in e, nerve fibers and puncta in f, a thickened nerve fiber adherent to a bundle of smooth muscle fibers in g and a ganglion cell with diffuse perikaryal cytoplasmic staining in h

Fig. 4

Relative frequency of PASH by diagnostic group for phosphorylated α-synuclein in different body regions including spinal cord, sympathetic ganglia, vagus nerve, sciatic nerve and multiple organs and tissues. Relative frequency is the percentage of subjects that showed immunoreactive tissue elements of any kind (fibers, puncta, perikaryal diffuse staining, perikaryal cytoplasmic inclusions) in single slides from each of the sites evaluated. For list of individual sites within each body region or organ system, see Table 1 and supplementary online table. Frequency was investigated further for some sites (see text)

Fig. 5

Relative frequency and density of PASH by diagnostic group in different spinal cord regions and sympathetic nervous system subdivisions. Relative frequency is the percentage of subjects that showed immunoreactive tissue elements of any kind (fibers, puncta, perikaryal diffuse staining, perikaryal cytoplasmic inclusions) in single slides taken from each of the sites evaluated. Density was calculated only for sites with immunoreactivity, negative or “zero” scores were not included