HSC Section 6 Nov2016 Green Book

Otolaryngology–Head and Neck Surgery 152(2)

Figure 5. Vocal folds. (A) Control group: collagen IV staining the vessel endothelium (arrow). (B, C) Elderly groups: collagen IV staining the vessel endothelium and the basement membrane (arrows). Immunohistochemical reaction, 20 3 .

Figure 6. Vocal folds. (A) Control group: collagen V staining the vessel endothelium (arrow). (B, C) Elderly groups: collagen V staining the vessel endothelium and the basement membrane (arrows). Immunohistochemical reaction, 20 3 .

Figure 7. Vocal folds. (A) Control group: uniform elastin antibody staining the lamina propria. (B, C) Elderly groups: sparse distribution of elastin in the lamina propria. Imunohistochemical reaction, 20 3 .

lamina propria collagen modulation, opening new perspec- tives for presbyphonia and vocal fold atrophy treatments. 25,28 The basement membrane and the vessels endothelium having a structural function, they also contain collagen types IV and V, which contribute to support the lamina pro- pria. 29 As in our results, it was observed that these antibo- dies, when quantified in said locations, also increased with age ( Table 2 ). Similar results have been reported in lar- ynges with chronic inflammation in morphological studies. 30 The increase of said collagens is probably related to the simultaneous increase of blood vessels, which is observed with both persistent inflammation and aging. Elastic fibers in the elderly larynx not only are found in lower amounts but also present structural alterations. Sato and Hirano 15 observed that with aging, these fibers lose elasticity because of an increase in amorphous sub- stance, a decrease in microfibrils, and their metabolic alteration. Thus, we can infer that synchronicity of the phonatory system can depend on biomechanic changes,

due to the physiological remodeling of the extracellular matrix. 31 We can therefore stress that the vibration mechanism of vocal folds is governed by the laryngeal tissue biomecha- nics. The observed alterations in the elderly larynx lamina propria components are interpreted in the endoscopic exami- nations as vocal fold atrophy and spindle chink, giving the voice different degrees of hoarseness, asthenia, and breathi- ness. 32 These ‘‘new’’ micro- and macroanatomic configura- tions present in the elderly larynx may mirror age-dependent physiological remodeling; that is, the structural changes in the vocal folds lamina propria that occur with aging make it necessary for the extracellular matrix and its components to be remodeled to remain functional.

Conclusions In our methodological conditions, we observed in the vocal folds lamina propria a clear increase of collagens I and III,

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