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Quantification of myelinated endings and mechanoreceptors in human digital skin.

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Quantification of Myelinated Endings and
Mechanoreceptors in Human Digital Skin
Maria Nolano, MD,1 Vincenzo Provitera, MD,1 Claudio Crisci, MD,1
Annamaria Stancanelli, Technician of Neurophysiopatology,1 Gwen Wendelschafer-Crabb, MS,2
William Robert Kennedy, MD,2 and Lucio Santoro, MD3
We used immunohistochemistry and confocal microscopy applied to fingertip punch biopsy to study glabrous skin
innervation in 14 healthy subjects. In addition to epidermal nerve fibers, we quantified mechanoreceptors and their
myelinated afferents. Using digital images and dedicated software, we calculated caliber, internodal and nodal length, and
G-ratio of the last four internodes of the myelinated endings. In our skin samples, we found a mean density of 59.0 ⴞ
29.3 myelinated endings per square millimeter with a mean diameter of 3.3 ⴞ 0.5␮m and an internodal length of
79.1 ⴞ 13.8␮m. These findings indicate that A␤ fibers undergo drastic changes in their course from the nerve trunk to
the target organ, with repeated branching and consequent tapering and shortening of internodal length. Our work
demonstrates that skin biopsy can give information on the status of large myelinated endings as well as unmyelinated
sensory and autonomic nerves. Since distal endings are primarily involved in distal axonopathy, skin biopsy can be more
suitable than sural nerve biopsy to detect early abnormalities. In addition to diagnostic applications, this technique
allows clarification of the mode of termination of A␤ fibers and their relationship with mechanoreceptors, leading to
relevant electrophysiological speculations.
Ann Neurol 2003;54:197–205
Quantification of epidermal nerve fibers (ENFs) by immunohistochemical study of skin biopsies has been
used in the last decade as a tool to diagnose and monitor small fiber neuropathies.1–9 Biopsies usually are acquired from hairy skin (thigh, leg, foot), which contains a rich supply of unmyelinated nerves plus a few
myelinated nerves to hair follicles or to sparse Merkel
complexes (MkCs). Glabrous skin has a different pattern of innervation. In addition to the unmyelinated
nerve fibers, there is a larger population of myelinated
nerve fibers; some enter dermal papillae, regularly
reaching the apex to furnish Meissner corpuscles
(MCs); others terminate at the base of the dermal papillae and innervate Merkel cells. Quantification of the
myelinated endings and mechanoreceptors in glabrous
skin of normal subjects can expand the diagnostic role
of skin biopsy to include all distal sensory axonopathies. This is especially valuable in the early stage,
when the distal impairment of receptors and nerve
endings cannot be detected by standard evaluation of
sensory nerve conduction.
We examined punch biopsies from digital skin of
normal subjects using immunohistochemistry and confocal microscopy and calculated the density of ENFs,
MCs, MkCs and myelinated nerve endings and described the morphology of myelinated nerve fibers and
receptor corpuscles.
From the 1Salvatore Maugeri Foundation, IRCCS, Center of Telese
Terme, Italy; 2Department of Neurology University of Minnesota,
Minneapolis, MN; and 3Department of Neurological Sciences, University of Naples, Federico II, Naples, Italy.
Address correspondence to Dr Nolano, Department of Neurology,
Salvatore Maugeri Foundation, IRCCS, Via Bagni Vecchi, 82037
Telese, Terme (BN), Italy. E-mail: mnolano@fsm.it
Subjects and Methods
Subjects
The subjects were 14 healthy volunteers, 6 men and 8
women, aged 22 to 53 years (mean, 33.7 ⫾ 9.2), without
symptoms or signs of neurological disease. Subjects with a
history of excessive use of tobacco10,11 or alcohol12 were excluded. Informed consent was obtained.
Skin Biopsies and Immunohistochemistry
A 3mm punch skin biopsy was taken from the fingertip of
digit III of each subject after intradermal injection of 1%
xylocaine. A second specimen was removed from digit V of
one subject.
After previously described procedures,1 samples were fixed
in Zamboni’s solution and cryoprotected in 20% sucrose in
phosphate-buffered saline. Thick, 80␮m sections were cut
Received Feb 10, 2003, and in revised form Apr 1. Accepted for
publication Apr 1, 2003.
© 2003 American Neurological Association
Published by Wiley-Liss, Inc., through Wiley Subscription Services
197
Table 1. Name, Source, and Dilution of Primary Antibodies
Antibody
Rabbit
Rabbit
Rabbit
Rabbit
Rabbit
Mouse
Mouse
Mouse
Abbreviation
Source
Dilution
r-PGP
r-SubP
r-CGRP
r-S100
r-VIP
m-PGP
m-Col IV
m-MBP
Biogenesis
Incstar
Amersham
Maxim Biotech
Incstar
Biogenesis
Chemicon
Ultraclone
1:1,000
1:1,000
1:1,000
1:10
1:1,000
1:800
1:800
1:800
anti–protein gene product 9.5
anti–substance p
anti–calcitonin gene–related peptide
anti–s100
anti–vasoactive intestinal peptide
anti–protein gene product 9.5
anti–collagen IV
anti–myelin basic protein
vertical to the skin surface, transversing the fingerprint ridges
at 90 degrees, using a freezing sliding microtome (Leica
2000R, Deerfield, IL). Free floating sections were incubated
overnight with a panel of primary antibodies (Table 1)
against neural and vascular antigens and then with secondary
antibodies labeled with cyanine 3.18 and 5.18 fluorophores
(Jackson ImmunoResearch, West Grove, PA). Ulex europaeus agglutinin I (UEA-I) was used to visualize the endothelium. Specificity controls were run for each biopsy.
Thick sections double stained for protein gene product
(PGP) and type IV collagen (Col IV) were imaged in a
CARV confocal microscope system (ATTO Biosciences,
Rockville, MD) connected to an Axioskop 2 Mot Zeiss
(Jena, Germany) microscope with a ⫻20 plan apochromat
objective. Digital confocal images (usually 16) were collected
at 2␮m increments at the appropriate wavelengths for cyanine 2 and 3 fluorphores. Images were projected together (a
z series) for viewing and quantification. ENF density (number of unmyelinated nerve fibers penetrating the basement
membrane per millimeter linear length of epidermis) was calculated as previously described2,13 from the stack of z-series
images with dedicated software (Neurolucida; MicroBrightField, Colchester, VT).
Quantification of MCs and their myelinated afferent
nerves was performed on an epifluorescent microscope. MCs
were counted on every other PGP-stained section, and their
afferent nerves, the intrapapillary myelinated endings (IMEs),
were counted on all the myelin basic protein (MBP)–stained
sections (five for each biopsy). The total surface of skin in
which MCs and IMEs were counted was measured
(length ⫻ depth of the sections) using an image analysis system (VIDAS; Zeiss), to calculate MC and IME density
(number of structures per square millimeter). To verify our
method of quantification, we counted myelinated nerve endings and mechanoreceptors in an entire fingertip specimen in
which all the sections were MBP/PGP double stained and
compared the results with the values obtained counting MCs
on alternate sections and IMEs on 5 of 20 sections. Two
specimens, one from the fifth and one from the third finger
were cut transversally (parallel to the epidermis), and all sections were double stained with MBP and PGP, to have a
better view of corpuscle distribution and neural plexus organization. The transverse cut allowed a reliable count of
MkCs that is difficult to perform in vertical sections because
of the size and shape of these complexes. The density of
MkCs and MCs on horizontal sections was calculated on
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two consecutive 80␮m superimposed sections to include all
the receptors.
Morphometric evaluation was performed on MBP-PGP
double-stained images acquired with the CARV system using
a ⫻20 plan apochromat objective. The length of IME of the
last four internodes and of the relative nodes of Ranvier was
measured in the stack of z-series images using Neurolucida
software. For each internode, the nerve diameter was measured at four different sites. The G-ratio (axon diameter/fiber
diameter) of cutaneous myelinated fibers was calculated using
higher magnification confocal images (⫻100 Plan Apochromat objective) and ScionImage (Scion Corporation, Frederick, MD) software (Fig 1). Digital images of MCs and MkCs
taken at ⫻100 magnification were acquired to better understand the structural features of these receptors.
From each 3mm skin biopsy, we obtained 20 (80␮mthick) sections with a maximum length of 2.4mm, because of
tissue shrinkage occurring during fixation, freezing, cutting,
and staining processes. We therefore calculated that, to extrapolate the density of myelinated nerve endings and mechanoreceptors in vital skin, we should correct all our counts
using a correction factor of 0.45. This value was calculated as
the ratio between the sum of the areas (length ⫻ 80␮m) of
all 20 sections from a processed biopsy (3.154mm2) and the
area of the vital tissue (7.065mm2).
We used Student’s t test for unpaired data to evaluate gender differences in morphological findings and simple regression line to correlate density of nervous structures and skin
area.
Results
Digital images of glabrous skin showed a rich subepidermal neural plexus with a regular distribution of
MCs at the apex, and an uneven presence of MkCs at
the base of dermal papillae (Fig 2A). One or two
MCs, approximately 30 by 80␮m with their long axis
vertically oriented, usually were located at the apex of
the dermal papillae, just below the basement membrane (see Fig 2B). Sometimes more than two MCs
in the same papilla were observed. The mean density
of corpuscles per square millimeter in the fingertip of
digit III was 33.02 ⫾ 13.2. In the only subject in
which we calculated MC density in both III and V
Fig 1. Protein gene product (PGP) (green) and myelin basic protein (MBP) (red) double-stained ⫻20 confocal images (A) have
been used for morphometric evaluation. Fiber diameter has been measured, evaluating the MBP staining (B), along each of the last
internodes (one internode in the outlined square in B is magnified in C) in four randomly selected points of the outlined image
(arrowheads in D). The G-ratio was calculated on ⫻100 micrographs (E), by outlining separately MBP (red) and PGP (green)
stainings (square in E) and measuring the respective calibers.
Nolano et al: Human Digital Skin Innervation
199
Fig 2. Confocal digital images of human glabrous skin showing morphology and distribution of nerve fibers and receptors in fingertip. In green, skin innervation (S100 in A and protein gene product [PGP] in B–I). In red, myelinated fibers (myelin basic protein) in B, G, and H; Meissner corpuscle capsula (Col IV) in C; peptidergic fibers in D (calcitonin gene-related peptide) and E
(substance P); vessels and epidermis (UEA-I) in F; Schwann cells (S100) in I. In blue, vessels and epidermis (UEA-I) in A and B.
Meissner corpuscles are regularly distributed at the apex of dermal papillae (arrows in A and B), whereas Merkel complexes (arrowheads in A, B, and F) are less represented and observed at the base close to sweat ducts. Large myelinated fibers innervate Meissner
corpuscles (B) and Merkel complexes (B, G, and H). Once myelinated fibers enter Meissner corpuscle, they lose myelin sheet and
branch repeatedly, assuming a ribbon-like shape with bulbous expansions (C). In addition to myelinated fibers, unmyelinated nerve
fibers that are calcitonin gene-related peptide (D) and substance P (E) immunoreactive enter Meissner corpuscles. The Merkel complex appears to be a long and thin structure whose density can be reliably evaluated on horizontal sections of skin (F). Its myelinated afferent assumes a typical sigmoidal aspect, and, once myelin is lost, it gives several branches, each branch ending with neural
expansions (I) that make close contact with vasoactive intestinal peptide-immunoreactive Merkel cells present in the basal layer of
the epidermis.
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digit fingertip, values were 33.6 and 45.0, respectively.
Fascicles of myelinated nerve fibers ran through the
deep dermis to the superficial dermis to give origin to
a subepidermal nerve plexus (SNP) located approximately 400␮m below the basement membrane at the
apex of the papillae. Small bundles of nerve separated
from the SNP and progressed a straight path in the
dermal papillae before reaching the MC. A single MC
frequently was furnished by more than one fiber (see
Fig 2B). From the SNP, some fibers ran for approximately 350␮m before reaching the corpuscle, usually at
its lower pole. Often a second fiber entered the same
corpuscle from the side (see Fig 2B) or bordered it to
reach its upper portion. Usually, fibers assumed a
coiled course before entering the corpuscle, then, after
losing the myelinated sheet, repeatedly branched and
terminated assuming a ribbon-like shape with bulbous
expansions (see Figs 2C and 3B, B’). The largest of
these formed a single flattened disc occupying the entire diameter of the corpuscle (see Fig 3A’, A“, B”).
Two such structures were identifiable in MCs innervated by two myelinated endings. Both bulbous and
disciform expansions appeared to fit perfectly in S100
immunoreactive lamellar structure (see Fig 3B, B’, B“).
When observed at high magnification, they were
clearly distinguishable from the dense contiguous helical network formed by thinner unmyelinated fibers.
These unmyelinated fibers appeared to be calcitonin
gene-related peptide and substance P immunoreactive
(see Fig 2D, E), the former being more represented
and more widely distributed inside the corpuscle and
showing a more varicose aspect compared with the latter. They entered the MCs together with the myelinated fibers forming loose loops in circumscribed, usually apical or basal, portions.
The density of intrapapillary myelinated nerve endings was 59.0 ⫾ 29.3 per square millimeter and their
diameter was 3.3 ⫾ 0.5␮m. The internodal length of
the last four internodes was 79.1 ⫾ 13.8␮m, with a
node length of 3.5 ⫾ 0.8␮m. The last value is higher
than expected based on electron microscopy studies.14
This is probably because the paranodal part of myelin
sheet reacts poorly to anti–MBP antibodies.
Only a few Merkel cells were present in most vertical
sections of the same specimen; an entire structure (or
almost entire structure) appeared to be a fortuitous
finding. A reliable count of MkCs was possible only in
the two specimens cut transversally where we found a
density of 4.1 and 3.9 complexes per square millimeter,
respectively. MkCs were long, thin structures (see Fig
2G, F) of approximately 30 ⫻ 250␮m and often were
in close proximity to sweat ducts, at the base of dermal
papillae (see Fig 2A, B). Their myelinated afferents assumed a typical sigmoidal aspect (see Fig 2G, H) repeatedly bending on themselves. After losing their my-
elin, they gave off several branches. Each branch,
accompanied by Schwann cells, ended with neural expansions of varying shapes and sizes, giving the whole
structure an hederiform aspect (see Fig 2I). These expansions made close contact with the VIPimmunoreactive Merkel cells present in the basal layer
of the epidermis.
ENFs were longer than in hairy skin, reflecting the
thicker epidermis, and rarely branched. They were unevenly distributed but were more often present in the
epidermis close to the apex of Meissner corpuscles. The
ENF mean density per linear millimeter was 11.1 ⫾
3.0. All quantitative and morphometric findings are reported in Table 2.
The density of MCs, IMEs, and ENFs was significantly higher ( p ⬍ 0.01) in female compared with
male subjects (see Table 2), but the fingertip surface of
the men was significantly larger ( p ⬍ 0.01).
An inverse correlation between fingertip surface
(whole volar aspect of distal phalanx) and MC, IME,
and ENF density (r2 ⫽ 0.71, 0.42, and 0.67, respectively) was present in all subjects independent of gender.
Discussion
In the past,15–18 punch biopsy of glabrous skin was
used to quantify MCs in normal subjects and in patients with hereditary neuropathies. The diagnostic
potential of skin biopsy was then neglected for several
decades. More recently, the ability to constantly visualize unmyelinated nerves using the effective panneuronal marker PGP 9.519 has enabled demonstration of the diagnostic capabilities of punch biopsy
(from hairy skin) in small fiber neuropathies. Although the function of myelinated fibers, unlike small
fibers, can be evaluated by routine electrophysiological tests, these technique fail to detect abnormalities
when the neuropathic process is limited to the most
distal part of nerve fibers or to receptors. Using a
3mm specimen from glabrous skin, we were able to
obtain information about receptors and myelinated fibers (large sensory fibers) as well as epidermal nerves
(unmyelinated sensory fibers) and sudomotor and vasomotor nerves (unmyelinated autonomic fibers).
This technique proved reliable because, compared
with normal findings, we found a completely different pattern of innervation and a marked loss of MCs,
IMEs, and ENFs in a population of patients with acquired or congenital sensory neuropathies.20 Comparable findings were described by other researchers,16
but their techniques did not allow such thorough visualization of distal afferents and receptors, or detection of early abnormalities of these structures. The
possibility of obtaining quantitative data about myelinated as well as unmyelinated nerve fibers leads us
to consider a biopsy from glabrous skin as a valid
Nolano et al: Human Digital Skin Innervation
201
Fig 3. Digital confocal images (A, B) at high magnification (⫻100) of Meissner corpuscles from fingertip (horizontal cut) obtained
from the projection of 60 1␮m-thick optical sections. Two single optical sections for each image are shown in A’, A”, and B’, B”,
respectively. In green, nerve fibers (PGP); in red: epidermis (UEA-I) in A, A’, and A” and corpuscle capsula (S100) in B, B’, and
B”. Once large myelinated fibers enter the corpuscle, they lose myelin sheet and the axon continues in large bulbous expansions that
perfectly fit in the S100-immunoreactive lamellar structure (B, B’, B”). One of these expansions appears disciform (A’, A”, B”) and
occupies the entire section of the corpuscle; it may play a major role in the mechanic-electric transduction process.
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Table 2. Normal Glabrous Skin Innervation: Quantitative Data and Morphometry
Subject
Initials
D.L.
D.I.
D.N.
G.C.
I.M.
I.V.
L.F.
M.I.
N.M.
N.S.
P.L.a
P.V.
R.C.
U.R.
Mean (SD)
a
Age
(yr)
Gender
M
F
F
F
F
F
M
F
F
M
F
M
M
M
22
31
25
30
35
25
40
25
41
53
48
36
33
28
33.7 (9.2)
ENF
Density
(no. of fibers/mm)a
MC
Density
(mm2)
IME
Density
(mm2)
IME
Diameter
(␮m)
14.1
11.9
12.8
10.8
13.3
12.0
6.9
14.8
15.6
9.1
32.4
38.8
36.3
32.4
51.9
66.7
31.6
31.1
33.6
20.7
27.2
20.0
16.4
23.1
33.0 (13.2)
39.1
100.0
76.8
37.7
71.0
113.0
55.9
48.0
96.2
32.6
3.82
3.21
3.41
3.21
3.01
3.57
3.15
3.36
4.54
3.38
2.84
2.61
3.09
3.00
3.30 (0.50)
7.4
7.4
10.4
11.3 (2.9)
26.3
35.4
34.8
59.0 (29.3)
Internode
(␮m)
G-ratio
100.1
89.8
66.3
78.8
79.9
89.2
56.3
73.9
95.6
76.8
0.73
0.78
0.71
0.71
0.67
0.76
0.73
0.73
0.78
0.72
0.71
77.2
0.79
63.0
0.73
81.6
0.64
79.1 (13.8) 0.73 (0.04)
In 50␮m-thick sections.
Specimen cut horizontally.
b
ENF ⫽ epidermal nerve fiber; MC ⫽ Meissner corpuscle; IME ⫽ intrapapillary myelinated ending; SD ⫽ standard deviation.
alternative to sural nerve biopsy to study sensory neuropathies. Skin biopsy has the relevant advantages of
being less invasive and repeatable over time thus allowing possible monitoring of a neuropathic process.
Moreover, because nerve endings and receptors are
the first structures to be involved in dying-back neuropathies, this technique can show abnormalities in
an early stage. In fact, we have observed involvement
of glabrous skin innervation in subjects with diabetes
in the absence of symptoms or clinical or electrophysiological signs of neuropathy.21
IMEs to MCs represent the more relevant population of myelinated endings in glabrous skin, the others being the afferents to MkCs. The density per
square millimeter of MCs is more than five times
higher than MkC density, and each MC is furnished
by one or more myelinated endings that follow a long
and linear course since they separate from the SNP.
Moreover MCs, and consequently their afferents, are
regularly and widely distributed at the apex of the
dermal papillae, allowing an easy and reliable count
in our 80␮m-thick sections. Therefore, we identified
the IME density as the most suitable parameter to
define the status of myelinated nerve fibers in glabrous skin.
The density of MCs and their afferents in our study
was significantly higher in female compared with male
subjects. However, as suggested,17 this finding does not
appear to be a gender characteristic but is the result of
the larger fingertip surface in men. This hypothesis is
corroborated by the observation that MC density was
higher in the fifth than in the third fingertip of the
only subject in which biopsies had been performed on
both sites. ENF density was similarly different between
male and female subjects. These findings suggest that
spatial distribution of receptors and nerve endings in
the skin is strongly affected by body growth. Several
previous studies22–25 described the morphology and
quantification of MCs in glabrous skin of normal subjects of different age, occupation, and gender and in
various body sites. In comparison with these reports,
we found density of MCs to be less variable and unrelated to subject age, but we performed our study with
subjects who were relatively homogeneous for age
(23–53 years) and occupation (students and physicians).
Morphological evaluation of MCs using highmagnification (⫻100) confocal images of horizontal
sections allowed us to clearly identify, among the neural expansions of myelinated endings, a disciform expansion occupying virtually the entire corpuscle section. Disagreement exists in the literature about the
number of such discs.26,27 Our high-magnification
confocal images allowed the identification of several
such expansions for each corpuscle related to the number of myelinated afferents. The peculiar features of
this disciform expansion suggest a primary role in the
mechanical-electrical transduction process.
We also identified the previously described unmyelinated fibers outside and inside MCs.23,28 These were
calcitonin gene-related peptide and substance P immunoreactive. The intracorpuscular unmyelinated fibers
occupy circumscribed areas contiguous to the disciform
expansion, suggesting their possible modulatory role on
Nolano et al: Human Digital Skin Innervation
203
mechanoreception. The complex innervation of these
receptors, as recently studied by Paré29 in primates using a wide panel of antibodies, led to speculation of a
polymodal role of MCs that includes a nociceptive
function.
Morphometric evaluation of cutaneous myelinated
fibers (caliber and internode length) is particularly important for making pathophysiological implications.
Several researchers have performed morphometric evaluations of sensory nerves along their course,30 –33 but
these fail to identify the terminal nerve segments and
the mode of termination in the target organ. In a previous study of correlation between nerve morphometry,
electrophysiological findings, and body growth, we
could not find any significant variation of fiber diameter along nerves between proximal and distal limb segments, against the hypothesis of a distal tapering of
nerve fibers. We had found, instead, a significant
proximal-distal reduction of internodal length along
nerve trunks, correlated with the finding of a reduced
elongation of distal limb segments in human body
growth. In particular along the median nerve, A␤ fiber
mean internodal length was 601.2 ⫾ 116.8␮m at digit
III and 927.1 ⫾ 187.4␮m at elbow.34 In our skin
samples, A␤ fiber endings showed a diameter of approximately 3.5␮m with an internodal length of
77.5 ⫾ 14.2␮m, demonstrating that this population of
fibers undergo drastic morphological changes in their
cutaneous segments. Moreover, we found a mean IME
density of 59.0 per mm2 (corresponding to 26.5 per
mm2 in the vital tissue) with a mean fingertip surface
of 848mm2. Extrapolating that approximately 22,500
(26.5 ⫻ 848) total nerve endings are present in the
distal phalanx, each of the approximately 1,500 large
myelinated fibers in the digital nerves34 should branch
several times to produce at least 15 endings. This is a
conservative evaluation taking into account that we
quantified the afferents of only one population of
mechanoreceptors. A repeated branching may explain
the marked reduction in diameter and the shortening
of internodal length of A␤ fibers when they reach the
skin. Our values are consistent with the findings of
Halata and Munger35 who observed a fiber diameter
reduction in terminal myelinated segments to mechanoreceptors in fortuitous observations on human prepuce (two samples) and opossum digital skin (one sample). In agreement with Halata’s findings, we observed
also a reduction of myelin thickness with a G-ratio
higher than the 0.6 value observed constantly along the
median nerve from elbow to digit III. Based on the
well-known correlations between internodal length, fiber diameter, and nerve conduction, the expected impulse velocity along the distal part of the mechanoreceptive pathway should be approximately 12m/sec;
much slower than hypothesized on the basis of digital
nerve morphometric data.34 In previous studies36,37 on
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conduction of sensory potentials along the median and
ulnar nerves evoked by mechanical or electrical stimuli,
we found a slower conduction in distal nerve segments
for tactile stimulation, hypothesizing that this finding
was because of mechanical-electrical transduction. The
results of this study lead us to reconsider the causes of
the discrepancy between electrical and tactile sensory
nerve conduction in the distal nerve segments, and to
attribute a preeminent role to the distal slowing of
nerve conduction along the thin endings of mechanoreceptor myelinated afferents.
Conclusions
Biopsy from glabrous skin allows for quantification of
cutaneous sensory myelinated fibers and mechanoreceptors as well as epidermal unmyelinated fibers.
Therefore, this technique is a reliable, minimally invasive, diagnostic tool to detect and monitor a sensory neuropathic process, especially in its earlier
stages.
Morphometric evaluation of myelinated endings in
glabrous skin clarifies the mode of termination of A␤
fibers and their relationship with mechanoreceptors resulting in relevant electrophysiological speculations.
This paper is dedicated to Prof. G Caruso, an unforgettable teacher.
It answers several questions that stimulated his life as a researcher.
We are grateful to F. Giuliano and F. Lullo for their technical assistance and to M. Selim and K. Wabner for revising the manuscript.
References
1. Kennedy WR, Wendelschafer-Crabb G. The innervation of human epidermis. J Neurol Sci 1993;115:184 –190.
2. Kennedy WR, Wendelschafer-Crabb G, Johnson T. Quantitation of epidermal nerves in diabetic neuropathy. Neurology
1996;47:1042–1048.
3. Wang L, Hilliges M, Jernberg T, et al. Protein gene product
9.5-immunoreactive nerve fibers and cell in human skin. Cell
Tissue Res 1990;261:25–33.
4. McCarthy BG, Hsieh ST, Stocks MA, et al. Cutaneous innervation in sensory neuropathies: evaluation by skin biopsy. Neurology 1995;45:1848 –1855.
5. Holland NR, Crawford TO, Hauer P, et al. Small-fiber sensory
neuropathies: clinical course and neuropathology of idiopathic
cases. Ann Neurol 1998;44:47–59.
6. Periquet MI, Novak V, Collins MP, et al. Painful sensory
neuropathy: prospective evaluation using skin biopsy. Neurology 1999;53:1641–1647.
7. Holland NR, Stocks MA, Hauer P, et al. Intraepidermal nerve
fiber density in patients with painful sensory neuropathy. Neurology 1997;48:708 –711.
8. Polydefkis M, Yiannoutsos CT, Cohen BA, et al. Reduced intraepidermal nerve fiber density in HIV-associated sensory neuropathy. Neurology 2002;58:115–119.
9. Scott LJ, Griffin JW, Luciano C, et al. Quantitative analysis of
epidermal innervation in Fabry disease. Neurology 1999;52:
1249 –1254.
10. Faden A, Mendoza E, Flynn F. Subclinical neuropathy associated with chronic obstructive pulmonary disease: possible
pathophysiologic role of smoking. Arch Neurol 1981;38:
639 – 642.
11. Barnouin J, Perez Cristia R, Chassagne M, et al. Vitamin and
nutritional status in Cuban smokers and nonsmokers in the
context of an emerging epidemic neuropathy. Int J Vitam Nutr
Res 2000;70:126 –138.
12. Vittadini G, Buonocore M, Colli G, et al. Alcoholic
polyneuropathy: a clinical and epidemiological study. Alcohol
Alcohol 2001;36:393– 400.
13. Nolano M, Provitera V, Crisci C, et al. Small fibers involvement in Friedreich’s ataxia. Ann Neurol 2001;50:17–25.
14. Thomas PK, Berthold CH, Ochoa J. Microscopic anatomy of
the peripheral nervous system. In: Dick PJ, Thomas PK, eds.
Peripheral neuropathy. 3rd ed. Philadelphia: Saunders, 1993:
28 –91.
15. Marolda M, Filla A, Giordano-Lanza G, et al. Diagnostic significance of pacinian corpuscle degeneration in Friedreich’s
ataxia. Acta Neurol 1980;5:373–381.
16. Dyck PJ, Winkelmann RK, Bolton CF. Quantitation of Meissner corpuscles in hereditary neurologic disorders. Neurology
1966;16:10 –17.
17. Bolton CF, Winkelmann RK, Dyck PJ. A quantitative study of
Meissner’s corpuscles in man. Neurology 1966;16:1–9.
18. Dickens NW, Winkelmann RK, Mulder DW. Cholinesterase
demonstration of dermal nerve endings in patients with impaired sensation. Neurology 1962;13:91–100.
19. Thompson RJ, Day INH. Protein gene product (PGP) 9.5 a
new neuronal and neuroendocrine marker. In: Marangos PJ,
Campbell IC, Cohen RM, eds. Neurobiological research. Vol 2.
Neuronal and glial proteins: structure, function and clinical application. San Diego: Academic Press, 1988:209 –228.
20. Nolano M, Provitera V, Lullo F, et al. Meissner corpuscles and
myelinated nerve fibers in human digital skin: a correlation
with electrophysiological findings. J Peripher Nerv Syst 2001;
6:165.
21. Nolano M, Provitera V, Lullo F, et al. Tactile stimulation and
mechanoreceptors in sensory neuropathies. Neurol Sci 2001;22:
S31–S36.
22. Ronge H. Alterveränderungen der Meissnerschen körperchen in
der fingerhaut. Z Mikrosk Anat Forsch 1943:54:167.
23. Cauna N. Nerve supply and nerve endings in Meissner corpuscles. Am J Anat 1956;99:315.
24. Cauna N. The mode of termination of the sensory nerves and
its significance. J Comp Neurol 1959;113:169 –209.
25. Winkelmann RK. Cutaneous sensory nerves. Semin Dermatol
1988;7:236 –268.
26. Castano P, Rumio C, Morini L, et al. Three-dimensional reconstruction of the Meissner’s corpuscles of man after silver impregnation and immunofluorescence with PGP 9.5 antibodies
using confocal scanning laser microscopy. J Anat 1995;186:
261–270.
27. Guinard D, Usson Y, Guillermet C, et al. PS-100 and NF 70200 double immunolabeling for human digital skin Meissner
corpuscles 3d imaging. J Histochem Cytochem 2000;48:
295–302.
28. Johansson O, Fantini F, Hu H. Neuronal structural proteins,
transmitters, transmitter enzymes and neuropeptides in human
Meissner’s corpuscles: a reappraisal using immunohistochemistry. Arch Dermatol Res 1999;291:419 – 424.
29. Paré M, Elde R, Mazurkiewicz JE, et al. The Meissner corpuscle revised: a multiafferented mechanoreceptor with nociceptor
immunochemical properties. J Neurosci 2001;21:7236 –7246.
30. Behse F. Morphometric studies on the human sural nerve. Acta
Neurol Scand Suppl 1990;82:1–38.
31. Sherrington CS. On the anatomical constitution of nerves of
skeletal muscles; with remarks on recurrent fibers in the ventral
spinal root. J Physiol (Lond) 1894;17:211–258.
32. Sunderland S, Lavarack JO, Ray LJ. The caliber of nerve fibers
in human cutaneous nerves. J Comp Neurol 1949;91:87–101.
33. Ochoa J, Mair WPG. The normal sural nerve in man. I. Ultrastructure and numbers of fibres and cells. Acta Neuropathol
(Berlin) 1969;13:197–216.
34. Caruso G, Massini R, Crisci C, et al. The relationship between
electrophysiological findings, upper limb growth and histological features of median and ulnar nerves in man. Brain 1992;
115:1925–1945.
35. Halata Z, Munger BL. The terminal myelin segments of afferent axons to cutaneous mechanoreceptors. Brain Res 1985;347:
177–182.
36. Caruso G, Nilsson J, Crisci C, et al. Sensory nerve findings by
tactile stimulation of median and ulnar nerves in healthy subjects of different ages. Electroenceph Clin Neurophysiol 1993;
89:392–398.
37. Caruso G, Nolano M, Lullo F, et al. Median nerve sensory
responses evoked by tactile stimulation of the finger proximal
and distal phalanx in normal subjects. Muscle Nerve 1994;17:
269 –275.
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