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Original Research—Laryngology and Neurolaryngology
Alterations in Extracellular Matrix
Composition in the Aging Larynx
Otolaryngology–
Head and Neck Surgery
2015, Vol. 152(2) 302–307
!
American Academy of
Otolaryngology—Head and Neck
Surgery Foundation 2014
Reprints and permission:
sagepub.com/journalsPermissions.navDOI: 10.1177/0194599814562727
http://otojournal.orgAnete Branco, SLP, PhD
1
, Alexandre Todorovic Fabro, MD, PhD
2
,
Tatiana Maria Gonc
x
alves, MD
1
, and
Regina Helena Garcia Martins, MD, PhD
1
Sponsorships or competing interests that may be relevant to content are dis-
closed at the end of this article.
Abstract
Objective.
To study by immunohistochemistry the alterations
of collagens I, III, IV, and V and elastin in the aging process of
the human larynx.
Study Design.
Cadaver study.
Setting.
Universidade Estadual Paulista, Botucatu Medical
School, Sa˜o Paulo State University (UNESP), Brazil.
Subjects and Methods.
Thirty vocal folds were obtained at
autopsy from 10 adult men (aged 30 to 50 years) and 20
geriatric men (10 aged 60 to 75 years and 10 aged
.
75
years). Mid membranous vocal fold slides were subjected to
immunohistochemical reactions. Digital imaging software
(ImageJ) was used to quantify the increase in brownish stain-
ing of the lamina propria structures of vocal folds, from
superficial to deep layers.
Results.
There was an increase of collagen I and III immu-
noexpression in the elderly larynges, in both layers.
Collagens IV and V were immunoexpressed in the vessels
endothelium of the lamina propria and in the basement
membrane. The immunoexpression of elastin decreased in
the elderly larynges, in both lamina propria layers of the
vocal folds.
Conclusion.
A clear increase of collagens I and III and a
decrease of elastic fibers were observed in the lamina pro-
pria of vocal folds. The concentration of collagens IV and V
was the same across age groups. These findings suggest that
as men age, the density of the extracellular matrix increases,
brought about by an increase in collagen, while the loss of
elastin results in decreased viscoelasticity.
Keywords
collagen, elastin, aged, lamina propria, vocal folds, larynx,
immunohistochemistry
Received May 15, 2014; revised October 28, 2014; accepted
November 14, 2014.
T
he physiology of voice production is intimately con-
nected with the characteristics of the vocal fold lamina
propria,
1,2
the vocal fold being the main vibrating
structure during phonation.
3
In the pursuit to understand the
vocal properties typical of age groups, sexes, and diseases,
researchers have gone deeper in their morphological studies,
trying to elucidate the mechanisms involving the lamina pro-
pria microstructures of vocal folds, mainly relating to elastic,
collagen, and protein fibers.
Collagen fibers are found across the whole lamina pro-
pria, from its superficial to its deepest layers,
4,5
supporting
tissue structure through enhanced stability and resistance,
relevant to vocal physiology. Gray et al
6
confirmed that col-
lagen and elastic fibers are involved in vocal fold biomecha-
nics, in which the former allow tension and stretching while
the latter allow deformation and a quick return to the initial
shape.
The composition of the vocal folds extracellular matrix
varies significantly between sexes and age groups, implying
biomechanical differences that directly influence the vocal
properties.
7
The lamina propria trilaminar structure in the
adult larynx described by Hirano
8
is not present in the new-
born.
3,9,10
It starts to organize only in childhood, from 6
years of age onward. In aging people, anatomical and func-
tional changes occur in the vocal tract, especially in the
vocal folds. At this stage of life, structural and functional
changes take place in the epithelial covering, the muscle,
and the lamina propria of vocal folds, notably, the atrophy
of epithelial layers and the vocal muscle, as well as density
alterations in collagen and elastic fibers and in hyaluronic
acid.
11-13
Elastic fibers change morphologically in elderly people,
relative to adults. Their remodeling with age is reflected by
1
Ophthalmology, Otorhinolaryngology, Head and Neck Surgery Depart-
ment, Botucatu Medical School, UNESP–Univ Estadual Paulista, Sa˜o Paulo,
Brazil
2
Department of Pathology, Botucatu Medical School, UNESP–Univ Estadual
Paulista, Sa˜o Paulo, Brazil
Corresponding Author:
Regina Helena Garcia Martins, SLP, PhD, Botucatu Medical School/UNESP,
Ophthalmology, Otorhinolaryngology, Head and Neck Surgery Department,
Distrito de Rubia˜o Jr, CEP 18618-970, Botucatu, Sa˜o Paulo, Brazil.
Email:
rmartins@fmb.unesp.brReprinted by permission of Otolaryngol Head Neck Surg. 2015; 152(2):302-307.
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