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The human endolymphatic sac expresses natriuretic peptides
Author(s) -
Møller Martin Nue,
Kirkeby Svend,
Vikeså Jonas,
Nielsen Finn Cilius,
CayéThomasen Per
Publication year - 2017
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.26074
Subject(s) - endolymphatic sac , medicine , microbiology and biotechnology , chemistry , biology , anatomy , inner ear
Objectives/Hypothesis The function of the human endolymphatic sac (ES) has been enigmatic for decades. Hypotheses include controlling endolymphatic fluid homeostasis and inner ear immunological defense. Additionally, several studies indicate a possible endocrine capacity and a yet undefined role in intracranial pressure homeostasis. However, no direct evidence of such capacity exists. This study aims to explore and identify the hypothesized endocrine capacity of the human ES. Study Design DNA microarrays and immunohistochemistry were used for analyses of fresh human ES tissue samples. Methods Twelve tissue samples from the human ES were obtained during translabyrinthine surgery for vestibular schwannoma. Microarray technology was used to investigate tissue sample gene expression. Genes specific for an endocrine function were determined, and results were verified by immunohistochemistry. Results Several natriuretic peptides were found expressed significantly in the ES, including uroguanylin and brain natriuretic peptide, but also peptides regulating vascular tone, including adrenomedullin 2. In addition, both neurophysin and oxytocin (OXT) were found significantly expressed. All peptides were verified by immunohistochemistry. Conclusion The present data support the hypothesis that the human ES may have an endocrine/paracrine capacity through expression of several peptides with potent natriuretic activity. Furthermore, the ES may influence the hypothalamo‐pituitary‐adrenal axis and may regulate vasopressin receptors and aquaporin‐2 channels in the inner ear via OXT expression. We hypothesize that the ES is likely to regulate inner ear endolymphatic homeostasis, possibly through secretion of several peptides, but it may also influence systemic and/or intracranial blood pressure through direct and indirect action on the vascular system and the kidney. Level of Evidence NA. Laryngoscope , 127:E201–E208, 2017