First-in-human intracochlear application of human stromal cell-derived extracellular vesicles

J Extracell Vesicles, 2021 · DOI: 10.1002/jev2.12094 · Published: April 22, 2021

Simple Explanation

Hearing loss affects millions worldwide, often due to hair cell damage. Cochlear implants bypass these cells to restore hearing, but have limitations, including difficulty hearing in noisy environments and potential damage to the inner ear during implantation. This study explores a new approach to reduce inflammation after cochlear implantation. Mesenchymal stromal cells (MSCs) can release factors that reduce inflammation. This study explores using extracellular vesicles (EVs) derived from umbilical cord MSCs (UC-MSC-EVs) to attenuate inflammation associated with cochlear implantation. This report details the first-in-human application of UC-MSC-EVs during cochlear implantation. A patient with Menière’s disease received UC-MSC-EVs during implantation in one ear, with the other ear serving as a control. The study monitored safety and implant performance over 24 months.

Study Duration

24 Months

Participants

One patient (male; age at implantation: 55 years)

Evidence Level

Level 4; Case Study

Key Findings

1
The intracochlear application of allogeneic UC-MSC-EVs during cochlear implantation appeared safe, with no acute systemic or local toxicity observed within the 5-day observation period and during the 24-month follow-up.
2
Speech intelligibility improved within the first year after implantation on the UC-MSC-EV-treated side and remained stable for the second year.
3
Impedance values, representing electrical resistance in the implant electrode contacts, were significantly higher on the UC-MSC-EV-treated side compared to the control side at certain measurement time points.

Research Summary

This study presents the first-in-human application of allogeneic UC-MSC-EVs during cochlear implantation, aiming to reduce inflammation and improve outcomes. A patient with Menière’s disease received UC-MSC-EVs in one ear during implantation, while the other ear served as a control. The results suggest that the local injection of UC-MSC-EVs is feasible and safe in principle, with no observed toxicity and improved speech intelligibility on the treated side. Impedance values also showed significant differences compared to the control side and historical data. Despite promising results, the study acknowledges that the experience from a single patient is insufficient for a robust safety and efficacy assessment. Further preclinical and clinical trials are necessary to investigate the immunological aspects and clinical benefits of UC-MSC-EV treatment in cochlear implantation.

Practical Implications

Potential Adjuvant Therapy

UC-MSC-EVs may serve as a potential adjuvant therapy to reduce inflammation and improve outcomes in cochlear implantation.

Future Clinical Trials

The findings support the initiation of clinical phase 1 and subsequent controlled trials to evaluate the safety and efficacy of UC-MSC-EVs in cochlear implantation.

Neurodegenerative Treatment

This study highlights the potential of EV-based therapies for neurodegenerative disorders affecting hearing.

Study Limitations

1
Experience from one single patient treatment is not sufficient for a robust safety assessment
2
No direct evidence could be provided by this single case observation that the EV-injection resulted in reduction of inflammation or other beneficial effects
3
The lack of measures to reliably demonstrate immunological responses after cochlear implantation in patients limits the quantification of anti-inflammatory effects of EVs

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