Journal Club: Analysis of blood vessels and auditory neurons in the human inner ear with Ménière’s disease

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Today's journal article

Curry SD, Lopez IA, Ishiyama G, Ishiyama A. Changes in the Neurovascular Unit in Meniere's Disease. 

Why I picked this article

Endolymphatic hydrops is the classic histology finding in Ménière’s disease (MD). But the hydrops alone do not fully explain symptoms. The cause of Ménière’s disease remains unclear; however, some evidence from MRI suggests changes to the barrier function of the blood vessels in the inner ear. 

Inner ear blood vessels have a very special barrier called the "blood–labyrinth barrier". This barrier is similar to the blood-brain barrier and is thought to have important roles in protecting the delicate balance inside the inner ear. 

This research uses human inner ear tissue from Ménière’s disease patient to understand any changes in the small vessels and neurons of the inner ear associated with this disease. 

Some of the research findings

Methodology:
  • Human temporal bones: MD n = 8 (age 51–88; 4 male/4 female) and age‑similar normal controls n = 5 (age 47–63; 1 male/4 female). 
  • Human temporal bones were made available through National Institute of Health-funded Human Temporal Bone Consortium for Research Resource Enhancement through the National Institute on Deafness and Other Communication Disorders.
  • Histology: hematoxylin and eosin for cochlear sections. 
  • Fluorescent confocal microscopy: spiral ganglion neurons (SGNs) labelled with acetylated‑3‑tubulin; blood vessels labelled with glucose transporter‑1 (GLUT1). 
  • Outcome measures: SGN counts per cochlea; qualitative/comparative assessment of microvasculature in Rosenthal’s canal regions.
Finding: 
  • SGN loss: MD cochleae showed about 50% fewer SGNs than age‑matched normal controls (P < 0.05).
  • Side comparison: relative to the contralateral, clinically unaffected ear, MD ears still showed ~35% SGN decrease. 
  • Vascular changes: immunofluorescence revealed a marked reduction in GLUT1‑positive microvessels in MD cases, spatially corresponding to SGN loss. 
  • Patterns of reduced vessels alongside neuronal loss support an NVU component in MD beyond endolymphatic hydrops. 

From Figure 2A. Blood vessel cells (green) and neurons and neuronal fibers (red) in the human cochlea. Curry et al. (2025)

Haruna's takeaway

Another publication on blood vessels! It's very exciting to see more focus on the vasculatures of the inner ear as we are also very interested in the area. What we can do with the knowledge is another thing; however, if blood vessel pathology is relevant to inner ear diseases, there is a huge bulk of vascular research done in other systems that we can perhaps learn from. This, in turn, may speed up our understanding of vascular pathophysiology and therapeutic implications. 
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This is Haruna's 91/100 of the 100-day challenge to post a science blog article every day! I love inner ear biology & cochlear physiology.