Human Endolymphatic Duct: An Ultrastructural Study

Friberg, Ulla; Rask‐Andersen, Helge; Bagger‐Sjöbäck, Dan

doi:10.1001/archotol.1984.00800330003001

Cited by 45 publications

(49 citation statements)

References 14 publications

(1 reference statement)

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“…The exact border between endolymphatic duct and sac is not clearly defined and is the subject of discussion. Recently, the endolymphatic duct has been suggested to be a short single lumen tubule only 2 mm long (24,30). The endolymphatic sac is variable in size and irregular in outline.…”

Section: Discussionmentioning

confidence: 99%

Effects of VHL Deficiency on Endolymphatic Duct and Sac

et al. 2005

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The von Hippel-Lindau (VHL) disease is caused by VHL germ line mutation. Inactivation of the wild-type copy of the VHL gene leads to up-regulation of hypoxic response and tumor formation within central nervous system (CNS), kidneys, pancreas, adrenal glands, epididymis, broad ligament, and the endolymphatic sac/petrous bone. Endolymphatic sac tumors (ELST) have been proposed to be derived from endolymphatic sac epithelium, but other possible structures of origin have been implicated. To clarify the anatomic and cellular origin of ELSTs, we did a morphologic and molecular pathologic analysis of 16 tumors. In addition, we investigated effects of VHL deficiency on ''tumor-free'' endolymphatic duct and sac of VHL patients. Several tumors included in this study were <1 cm in size, and their origin could be placed in the intraosseous portion of the endolymphatic duct/sac. Furthermore, by analysis of clinically uninvolved ''tumor-free'' endolymphatic duct and sac tissues of VHL patients, we discovered a variety of VHL-deficient microscopic abnormalities with morphologic similarities to ELSTs. We conclude that most, if not all, ELSTs arise within the intraosseous portion of the endolymphatic duct/sac, the vestibular aqueduct. In analogy to renal parenchyma and selected topographical sites within the CNS, endolymphatic duct/sac epithelia are preferentially and multifocally targeted in VHL disease. The primary effect of VHL deficiency on human endolymphatic duct/sac epithelium seems to be the generation of multifocal sites of VHL-deficient cell proliferations from which tumorigenesis may or may not occur. Therefore, inactivation of the VHL wild-type allele seems necessary but not sufficient for the formation of tumor. (Cancer Res 2005; 65(23): 10847-53)

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Section: Discussionmentioning

confidence: 99%

Effects of VHL Deficiency on Endolymphatic Duct and Sac

et al. 2005

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“…The ED forms a narrow tubule with a single layer epithelium leading to the endolymphatic sac (ES) through the vestibular aqueduct (VA) of the petrous bone. The ED is surrounded by a loose interstitial connective tissue (CT) also filling up numerous bone cavities parallel to the aqueduct (Friberg et al 1984). The interstitial cells are organized in a tissue network structure with prominent intercellular and cell-extracellular matrix (ECM) contacts (Hultgard-Ekwall et al 2003).…”

Section: Introductionmentioning

confidence: 99%

An Interstitial Network of Podoplanin-Expressing Cells in the Human Endolymphatic Duct

Ekwall

Mayerl

Rubin

et al. 2006

JARO

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The human endolymphatic duct (ED) with encompassing interstitial connective tissue (CT) is believed to be important for endolymph resorption and fluid pressure regulation of the inner ear. The periductal CT cells are interconnected via numerous cellular extensions, but do not form vessel structures. Here we report that the periductal CT is populated by two distinct cell phenotypes; one expressing podoplanin, a protein otherwise found on lymph endothelia and on epithelia involved in fluid fluxes, and a second expressing a fibroblast marker. A majority of the interstitial cells expressed podoplanin but not the lymphatic endothelial cell markers hyaluronan receptor (LYVE-1) or vascular endothelial growth factor receptor-3 (VEGFR-3). The fibroblast marker positive cells were found close to the ED epithelium. In the mid-and distal parts of the ED, these cells were enriched under folded epithelia. Furthermore, subepithelial CT cells were found to express activated platelet derived growth factor (PDGF)-" receptors. Cultured CT cells from human inner ear periductal and perisaccular explant tissues were identified as fibroblasts. These cells compacted a three-dimensional collagen lattice by a process that could be promoted by PDGF-BB, a factor involved in interstitial fluid pressure regulation. Our results are compatible with the notion that the periductal CT cells are involved in the regulation of inner ear fluid pressure. By active compaction of the periductal CT and by the formation of villous structures, the CT cells could modulate fluid fluxes over the ED epithelium as well as the longitudinal flow of endolymph in the ED.

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“…Waste products from the rest of the inner ear are believed to be transported to the ES by the longitudinal flow of endolymph [1]. Studies on the human ES with transmission electron microscopy (TEM) have revealed degenerated cell products [11], red blood corpuscles, discarded otoconia and collagen fibres [12] in the lumen. TEM studies on ES from patients with Ménière's disease (MD) and acoustic neuroma showed that luminal contents often included degenerated cell products originating mainly from the ES itself [13,14].…”

Section: Introductionmentioning

confidence: 99%

Stereocilia-Like Structures in the Endolymphatic Sac in Ménière’s Disease and Acoustic Neuroma

Danckwardt-Lillieström

Friberg²,

Kinnefors³

et al. 1998

ORL

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The vestibular aqueduct was surgically removed in 3 patients undergoing labyrinthectomy due to severe Ménière’s disease (MD). Stereocilia-like structures were found in the luminal contents of the endolymphatic sac (ES) in all of these patients. The ES from 18 patients with acoustic neuroma were used as controls. In 1 of these, numerous stereocilia-like structures were found in the ES and in 3 additional patients, a few isolated cilia-like structures were disclosed. The findings may suggest an ongoing hair cell degeneration in the inner ear that is more advanced in patients with MD. The data also suggest that the endolymphatic duct is patent and that a longitudinal flow of endolymph also occurs in patients with MD.

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Human Endolymphatic Duct: An Ultrastructural Study

Cited by 45 publications

References 14 publications

Effects of VHL Deficiency on Endolymphatic Duct and Sac

Effects of VHL Deficiency on Endolymphatic Duct and Sac

An Interstitial Network of Podoplanin-Expressing Cells in the Human Endolymphatic Duct

Stereocilia-Like Structures in the Endolymphatic Sac in Ménière’s Disease and Acoustic Neuroma

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