Multimodal approach to characterize surgically removed epileptogenic zone from patients with focal drug-resistant epilepsy: from operating room to wet lab

Kyyriainen, J.; Della Pietra, A.; Torkamani-Azar, M.; Gomez- Budia, M.; Novosolova, N.; Eronen, H.; Narvaez, O.; Paasonen, E.; Lezhneva, V.; Pelkonen, A.; Saveleva, L.; Huotarinen, A.; Jutila, L.; Rauramaa, T.; Immonen, A.; Leinonen, V.; Tohka, J.; Grohn, O.; Kalviainen, R.; Malm, T.; Sierra, A.

doi:10.1101/2025.04.15.648977

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bioRxiv · 10.1101/2025.04.15.648977

Multimodal approach to characterize surgically removed epileptogenic zone from patients with focal drug-resistant epilepsy: from operating room to wet lab

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Abstract

ObjectiveWe have established a comprehensive sample handling protocol designed for the multiscale assessment of epileptogenic tissue. This protocol aims to identify novel therapeutic targets and enhance the diagnosis and stratification of patients with drug-resistant epilepsy, thereby optimizing their treatment with anti-seizure medications and surgical interventions. MethodsPatients with drug-resistant focal epilepsy, recommended for surgical treatment, are recruited after detailed multidisciplinary preoperative evaluation at the Epilepsy Center at Kuopio University Hospital in Finland. A day before the resective surgery, patients undergo magnetic resonance imaging (MRI) including advanced methodologies. During the surgery, each piece of resected tissue is placed under oxygenation on ice-cold artificial cerebral spinal fluid-solution. The pieces are then immediately transported to the laboratory, assessed by a neuropathologist, and sliced for both clinical diagnosis and research. Two adjacent slices are provided for research and are sent to the University of Eastern Finland. ResultsThe developed sample handling protocol provides the opportunity for detailed characterization of the tissue from the same patient using emerging imaging, electrophysiology, and molecular biology technologies. We have optimized the conditions for preserving the resected tissue alive for electrophysiological measurements and simultaneously making possible ex vivo studies including multi-omics acquisition, electron microscopy, histology, and MRI. Our protocol enables the mapping of functional readouts to structural and molecular alterations in human tissue. Our goal is to integrate multimodal data and co-register the resected tissues within the whole brains in vivo MRI space. This approach aims to enhance the characterization and localization of epileptogenic zones and refine surgical treatment targets by identifying abnormalities in global connectivity and structural patterns. SignificanceWe have successfully developed a systematic protocol for the collection and analysis of multimodal data. This protocol aims to elucidate the structural, functional, and molecular characteristics that render tissue epileptogenic, thereby enhancing the diagnosis and subsequent care of patients with epilepsy. Key pointsO_LIIntroducing a systematic sample handling protocol to assess tissue epileptogenicity at structural, functional and molecular levels. C_LIO_LIA multimodal approach integrating advanced technology with detailed characterization of epileptogenic tissue properties to obtain patient-specific data. C_LIO_LICorrelation of data from preoperative MRI and resected tissue to predict tissue pathology from clinical MRI. C_LI

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Kyyriainen, J., Della Pietra, A., Torkamani-Azar, M., Gomez- Budia, M., Novosolova, N., Eronen, H., Narvaez, O., Paasonen, E., Lezhneva, V., Pelkonen, A., Saveleva, L., Huotarinen, A., Jutila, L., Rauramaa, T., Immonen, A., Leinonen, V., Tohka, J., Grohn, O., Kalviainen, R., Malm, T., Sierra, A.. 2025-04-20. Multimodal approach to characterize surgically removed epileptogenic zone from patients with focal drug-resistant epilepsy: from operating room to wet lab. https://doi.org/10.1101/2025.04.15.648977

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