[Introduction]
We have been developing a method for predicting seizure liability of drugs using in vitro human iPSC-derived neurons. However, it is necessary to approach the in vitro to in vivo extrapolation (IVIVE). As one approach to IVIVE, an assessment method using a human brain organoid that mimics the three-dimensional structure is considered to be effective. In this study, we attempted to detect the response to convulsants by MEA measurement using human cerebral cortical organoids.
[Methods]
Human cerebral organoids were prepared using the STEMdiff Cerebral Organoid kit from STEMCELL Technologies. After 6 months of culture, the human cerebral organoids were placed on the MEA (Alpha med scientific), and spontaneous activity was recorded at 37℃, 5% CO2. Next, strychnine and 4-Aminopyridine (4-AP) were administered to detect response to convulsants.
[Result]
Spontaneous activity waveforms of brain organoids were observed in low frequency components. Almost no spike components as detected in the cultured neural network were detected. After strychnine administration, the shape and frequency of the slow wave changed in a dose-dependent manner. Wavelet analysis revealed that the frequency intensity from the θ wave to the β wave component significantly increased in a dose-dependent manner. Also in the 4-AP administration, an increase in the frequency intensity from the θ wave to the β wave component was observed. An increase in the number of synchronized burst firings specific to 4-AP was detected. It was found that responses to convulsants with different mechanisms of action could be detected in human brain organoids.
[Conclusion]
We succeeded in detecting electrophysiological activities of human cerebral cortical organoids by analyzing low frequency components in MEA data. In addition, it has been found that the component from the θ wave to the β wave is enhanced by the administration of convulsants. This is a result that enables comparison with in vivo brain waves. This study demonstrated that MEA measurement using human brain organoids may be a method that can approach in vitro to in vivo extrapolation in prediction of seizure liability of drugs.
