Ischemia of the endolymphatic sac

Area of Science:

• Otolaryngology
• Pathophysiology
• Vascular Biology

Background:

• Meniere's disease is characterized by endolymphatic hydrops.
• A decrease in vascular density within the endolymphatic sac has been hypothesized to contribute to its pathogenesis.

Purpose of the Study:

• To investigate the role of vascular changes in the endolymphatic sac in the development of endolymphatic hydrops.
• To explore the potential link between vascular compromise and Meniere's disease pathology.

Main Methods:

• Surgical intervention in 18 guinea pigs, including ablation of the posterior meningeal artery and sigmoid sinus or dural incision.
• Induction of vascular lesions in the endolymphatic sac.
• Histopathological examination of the endolymphatic sac epithelia and inner ear structures.

Main Results:

• Segmental ablation of the artery and sinus led to significant lesions in the endolymphatic sac and consistent development of endolymphatic hydrops.
• The intermediate portion of the endolymphatic sac showed the most severe epithelial changes, including reduced rugosity and cellular flattening.
• Sac luminal precipitates, often increased in human Meniere's disease, were decreased or absent in this model.

Conclusions:

• Vascular compromise of the endolymphatic sac, particularly its intermediate portion, plays a critical role in the pathogenesis of endolymphatic hydrops.
• The findings support the hypothesis that substances accumulating in the sac lumen are secreted by the endolymphatic sac itself.
• Observed sensory cell lesions in the cochlea and saccule are likely secondary to transient vascular ischemia and hydrops.