The capsule of human Meissner corpuscles: immunohistochemical evidence

Abstract

Meissner corpuscles are cutaneous mechanoreceptors that are usually located in the dermal papillae of human glabrous skin. Structurally, these sensory corpuscles consist of a mechanoreceptive sensory neuron surrounded by non-myelinating lamellar Schwann-like cells. Some authors have described a partially developed fibroblastic capsule of endoneurial or perineurial origin around Meissner corpuscles; however, others have noted that these structures are non-encapsulated. As there is continuity between the periaxonic cells forming the sensory corpuscles and the cells of the nerve trunks, we used immunohistochemistry to examine the expression of endoneurial (CD34 antigen) or perineurial [Glucose transporter 1 (Glut1)] markers in human cutaneous Meissner corpuscles. We also investigated the immunohistochemical patterns of nestin and vimentin (the main intermediate filaments of the cytoskeleton of endoneurial and perineurial cells, respectively) in Meissner corpuscles. The most important finding from this study was that CD34-positive cells formed a partial/complete capsule of endoneurial origin around most Meissner corpuscles, without signs of other perineurial Glut1positive elements. However, the cytoskeletal proteins of the capsular CD34-positive cells did not include either nestin or vimentin, so the cytoskeletal composition of these cells remains to be established. Finally, the intensity of the immunoreactivity for CD34 in the capsule decreased with ageing, sometimes becoming completely absent in the oldest individuals. In conclusion, we report the first immunohistochemical evidence of the capsule of Meissner corpuscles in humans and demonstrate the endoneurial origin of the capsule.

Telocytes in the Normal and Pathological Peripheral Nervous System

“…In Meissner corpuscles, TCs (TCs/CD34+SCs) form a complete or incomplete capsule ( Figure 2 A). Glut-1+perineurial cells do not participate in this capsule [ 62 ]. The intensity of immunoreactivity for TCs/CD34+SCs can decrease or disappear with ageing [ 62 ].…”

Peripheral Mechanobiology of Touch—Studies on Vertebrate Cutaneous Sensory Corpuscles

“…Structurally, cutaneous sensory corpuscles consist of a central axon, surrounded by non-myelinating Schwann-like cells variably arranged, and a capsule of endoneurial and/or perineurial derivation [ 6 , 17 , 28 , 29 ]. It must be emphasized that although the term central axon is widely used to denominate the neuronal component of sensory corpuscles, it actually represents the peripheral process of a pseudo-unipolar neuron, localized in dorsal root ganglia (DRG) or the sensory ganglia of the cranial nerves.…”

“…Meissner’s corpuscles’ size and morphology are varied, but often they present an ellipsoid morphology being 80–150 μm in length and 20–40 μm in diameter [ 5 , 6 ]. They consist of an axon from an Aβ nerve fiber, non-myelinating lamellar Schwann-related cells, and a more or less developed capsule of endoneurial origin [ 29 , 44 ].…”

The Glial Cell of Human Cutaneous Sensory Corpuscles: Origin, Characterization, and Putative Roles

“…The organization of the lamellar has a typical flattened appearance due to the horizontal lamelation that form stacks of lamellae separated by axon branches [8,58]. Habitually the nuclei of the cells are at the periphery of the corpuscle and are total or partially covered by a CD34-positive capsule of endoneurial origin [13] (Figure 1).…”

“…The peripheral processes of Aβ axons contact in the skin with specialized epithelial cells, i.e., Merkel cells to form Merkel cell-neurite complexes, or with glial Schwann-like cells to form a part of the sensory corpuscles, i.e., Meissner corpuscles, Ruffini's corpuscles, and Pacinian corpuscles [1,3,8,9]. Structurally, the cutaneous sensory corpuscles consists of a dendritic zone (the extreme tip of the peripheral process of an Aβ LTMR), surrounded by nonmyelinating glial cells variably arranged, and both are surrounded by a more or less developed capsule of endoneurial/perineurial cells [9][10][11][12][13]. Filling the spaces among cells, there is a chemically complex extracellular matrix, sometimes organized as a basal lamina [14][15][16][17].…”