Engineering vascularized inner ear organoids: Challenges and advances in recapitulating the cochlear microenvironment

Area of Science:

• Biomedical Engineering
• Stem Cell Biology
• Otolaryngology

Background:

• The inner ear's complex structure and limited human tissue access hinder auditory and vestibular research.
• Inner ear organoids (IEOs) and organoid-on-a-chip systems offer promising alternatives for studying hearing loss.
• Developing functional models of the inner ear is crucial for understanding its intricate functions.

Purpose of the Study:

• To review recent advancements in generating human inner ear organoids (IEOs) from pluripotent stem cells.
• To highlight progress in reconstructing the blood-labyrinth barrier (BLB) within organoid models.
• To explore strategies for enhancing vascularization in IEOs for improved disease modeling and therapeutic applications.

Main Methods:

• Generation of IEOs from human pluripotent stem cells, differentiating into hair cells and spiral ganglion neurons.
• 3D culture, co-culture, and microfluidic techniques for IEO development.
• Strategies for vascularizing organoids, inspired by brain and kidney organoid models, focusing on microfluidic integration.

Main Results:

• Successful differentiation of stem cells into key inner ear cell types within organoids.
• Progress in reconstructing the blood-labyrinth barrier (BLB) and assessing its integrity.
• Identification of microfluidic approaches to improve vascularization and recapitulate the cochlear microenvironment.

Conclusions:

• Vascularized IEOs hold significant potential for advancing hearing loss research and treatment.
• These organoid models can facilitate drug screening and the development of regenerative therapies.
• Improved vascularization is key to creating more accurate and functional inner ear models for future studies.