The human endolymphatic sac expresses natriuretic peptides

TY - JOUR

T1 - The human endolymphatic sac expresses natriuretic peptides

AU - Møller, Martin Nue

AU - Kirkeby, Svend

AU - Vikeså, Jonas

AU - Nielsen, Finn Cilius

AU - Cayé-Thomasen, Per

N1 - © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

PY - 2017/6

Y1 - 2017/6

N2 - 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.

AB - 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.

KW - Journal Article

U2 - 10.1002/lary.26074

DO - 10.1002/lary.26074

M3 - Journal article

C2 - 28295370

SN - 0023-852X

VL - 127

SP - E201-E208

JO - The Laryngoscope

JF - The Laryngoscope

IS - 6

ER -