TY - JOUR
T1 - High frequency oscillations associate with neuroinflammation in low-grade epilepsy associated tumors
AU - Sun, Dongqing
AU - van Klink, Nicole E. C.
AU - Bongaarts, Anika
AU - Zweiphenning, Willemiek E. J. M.
AU - van 't Klooster, Maryse A.
AU - Gebbink, Tineke A.
AU - Snijders, Tom J.
AU - van Eijsden, Pieter
AU - Robe, Pierre A. J. T.
AU - Aronica, Eleonora
AU - Zijlmans, Maeike
N1 - Funding Information: This work was supported by the European Research Council starting grant 803880 and N.v.K. was supported by the Dutch Brain Foundation (2013-139). Figs. 1 and 2 were created with BioRender.com. Publisher Copyright: © 2021 International Federation of Clinical Neurophysiology
PY - 2022/1
Y1 - 2022/1
N2 - Objective: High frequency oscillations (HFOs) in intraoperative electrocorticography (ioECoG) are thought to be generated by hyperexcitable neurons. Inflammation may promote neuronal hyperexcitability. We investigated the relation between HFOs and inflammation in tumor-related epilepsy. Methods: We identified HFOs (ripples 80–250 Hz, fast ripples 250–500 Hz) in the preresection ioECoG of 32 patients with low-grade tumors. Localization of recorded HFOs was classified based on magnetic resonance imaging reconstructions: in tumor, in resected non-tumorous area and outside the resected area. We tested if the following inflammatory markers in the tumor or peritumoral tissue were related to HFOs: activated microglia, cluster of differentiation 3 (CD3)-positive T-cells, interleukin 1-beta (IL1β), toll-like receptor 4 (TLR4) and high mobility group box 1 protein (HMGB1). Results: Tumors that generated ripples were infiltrated by more CD3-positive cells than tumors without ripples. Ripple rate outside the resected area was positively correlated with IL1β/TLR4/HMGB1 pathway activity in peritumoral area. These two areas did not directly overlap. Conclusions: Ripple rates may be associated with inflammatory processes. Significance: Our findings support that ripple generation and spread might be associated with synchronized fast firing of hyperexcitable neurons due to certain inflammatory processes. This pilot study provides arguments for further investigations in HFOs and inflammation.
AB - Objective: High frequency oscillations (HFOs) in intraoperative electrocorticography (ioECoG) are thought to be generated by hyperexcitable neurons. Inflammation may promote neuronal hyperexcitability. We investigated the relation between HFOs and inflammation in tumor-related epilepsy. Methods: We identified HFOs (ripples 80–250 Hz, fast ripples 250–500 Hz) in the preresection ioECoG of 32 patients with low-grade tumors. Localization of recorded HFOs was classified based on magnetic resonance imaging reconstructions: in tumor, in resected non-tumorous area and outside the resected area. We tested if the following inflammatory markers in the tumor or peritumoral tissue were related to HFOs: activated microglia, cluster of differentiation 3 (CD3)-positive T-cells, interleukin 1-beta (IL1β), toll-like receptor 4 (TLR4) and high mobility group box 1 protein (HMGB1). Results: Tumors that generated ripples were infiltrated by more CD3-positive cells than tumors without ripples. Ripple rate outside the resected area was positively correlated with IL1β/TLR4/HMGB1 pathway activity in peritumoral area. These two areas did not directly overlap. Conclusions: Ripple rates may be associated with inflammatory processes. Significance: Our findings support that ripple generation and spread might be associated with synchronized fast firing of hyperexcitable neurons due to certain inflammatory processes. This pilot study provides arguments for further investigations in HFOs and inflammation.
KW - Epilepsy surgery
KW - High frequency oscillations
KW - Intraoperative electrocorticography
KW - Low-grade tumor
KW - Neuroinflammation
UR - http://www.scopus.com/inward/record.url?scp=85119000429&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.clinph.2021.08.025
DO - https://doi.org/10.1016/j.clinph.2021.08.025
M3 - Article
C2 - 34774442
SN - 1388-2457
VL - 133
SP - 165
EP - 174
JO - Clinical neurophysiology
JF - Clinical neurophysiology
ER -