Immunohistochemistry of Displaced Sensory Neurons in the Trigeminal Nerve Root

Abstract

The aim of this study was to examine the morphology and the immunohistochemical features of displaced ganglion cells in the trigeminal nerve root (TNR). Forty human TNRs of 20 persons, obtained during routine autopsy in accordance with the Declaration of Helsinki, were examined following Klüver-Barrera and azan trichrome histological staining, and immunohistochemical reactions against certain neuronal markers, neuropeptides and neurotransmitters. A total number of 61 displaced neurons were investigated, which were present in 80% of individuals studied. Displaced neurons were found in 55.0% of the TNRs, either in the sensory portion (22.5%), motor portion (22.5%) or both (10.0%). Neuronal diameter varied from 12.5 × 25.0 to 45.0 × 63.7 (mean 27.6 × 41.6) µm, and in area between 245 and 2,065 (mean 927) µm². Each neuron was surrounded by 2–17 elongated satellite cells per slice. The immune reaction was positive in all the neurons studied for neuron-specific enolase, protein gene product 9.5, neurofilament protein and synaptophysin, and in some neurons for calcitonin gene-related peptide (CGRP; 24.4%), cholecystokinin (CCK; 13.3%), somatostatin (SST; 17.8%), substance P (SP; 15.6%), vasoactive intestinal polypeptide (4.4%), neuropeptide Y (8.9%), and serotonin (11.1%). The immune reactions were most frequent against the CGRP, SP, CCK and SST. We concluded that displaced neurons in the TNR morphologically and immunohistochemically resembled the sensory neurons in the trigeminal ganglion.

Longitudinal alterations of the cisternal segment of trigeminal nerve and brain pain-matrix regions in patients with trigeminal neuralgia before and after treatment

“…Our study also demonstrated that patients with TN not only had lower FA but also had higher AD, RD, and MD values at the affected REZ. Consistent with a prior study [ 24 ], our findings suggested that the increased MD and RD may be linked to NVC-induced focal demyelination in the trigeminal nerve REZ [ 25 ], neuroinflammatory processes, and/or edema [ 26 ] that affected the trigeminal system. Therefore, DTI can detect subtle pathological features at the trigeminal nerve REZ supporting a role for this regional involvement in TN pathophysiology.…”

Longitudinal Alterations of the Cisternal Segment of Trigeminal Nerve and Brain Pain-matrix Regions in Patients with Trigeminal Neuralgia Before and After Treatment

“…Our study also demonstrated that patients with TN not only had lower FA but also had higher AD, RD, and MD values at the affected REZ. Consistent with a prior study [24], our ndings suggested that the increased MD and RD may be linked to NVC-induced focal demyelination in the trigeminal nerve REZ [25], neuroin ammatory processes, and/or edema [26] that affected the trigeminal system. Therefore, DTI can detect subtle pathological features at the trigeminal nerve REZ supporting a role for this regional involvement in TN pathophysiology.…”

Structural Magnetic Resonance Imaging Can Identify Trigeminal System Abnormalities in Classical Trigeminal Neuralgia

“…Recently, we assessed all four of these described diffusion metrics at the trigeminal REZ and demonstrated that TN patients not only have lower FA at their affected REZ, but also higher AD, RD and MD (DeSouza et al, 2014 ; Figure 3 ). Our finding of increased MD and RD may be linked to NVC-induced focal demyelination of the trigeminal REZ (Marinković et al, 2010 ), neuroinflammatory processes, and/or edema (Beaulieu, 2002 ) affecting the trigeminal system, since these increases were also observed at the unaffected REZ. Therefore, DTI can detect subtle pathological features at the trigeminal REZ supporting a role for this region’s involvement in TN pathophysiology.…”