Submitted by Clark Pinyan
A Model to Study Myelinated Fiber Degeneration and Regeneration in Human Skin
Provitera V et al. Ann Neurol 2020;87:456-465
The authors sought to describe changes with degeneration and regeneration of large myelinated fibers and Meissner corpuscles (MC) in a cohort of patients with median nerve compression at the wrist, pre and post surgery. 30 patients with moderate median nerve compression scheduled for surgery underwent clinical assessment, qualitative sensory testing, electrodiagnostic (EDX) testing, and a 2mm biopsy from the third digit fingertip. Biopsies were compared to 30 matched controls. Clinical and EDX assessments were repeated in the study group at 12 month follow up, and 15 patients underwent repeat biopsy. Presurgical patients demonstrated a decreased density of intraepidermal nerve fibers and intrapapillary myelinated endings. Myelinated fibers showed caliber reduction and nodal elongation. MC had normal density but were smaller, located deeper in the dermis and capsule appeared partially empty. In follow up, the caliber of intrapapillary myelinated endings was increased, MC appeared more filled, but remained deeper in the dermis. Vasoactive intestinal peptide-reactive fibers were more superficial. At onset, clinical symptom severity correlated with myelinated fiber nodal gap length, MC size, density, and depth.
Comments: This study describes changes in large, myelinated fibers in a naturally occurring degenerative and regenerative model, using changes that can be seen in glabrous skin (as opposed to small intraepidermal fibers in a hairy skin biopsy).