The value of ictal scalp EEG in focal epilepsies surgery: a retrospective analysis.

OBJECTIVE: To describe the association between preoperative ictal scalp electroencephalogram (EEG) results and surgical outcomes in patients with focal epilepsies. METHODS: The data of consecutive patients with focal epilepsies who received surgical treatments at our center from January 2012 to December 2021 were retrospectively analyzed. RESULTS: Our data showed that 44.2% (322/729) of patients had ictal EEG recorded on video EEG monitoring during preoperative evaluation, of which 60.6% (195/322) had a concordant ictal EEG results. No significant difference of surgery outcomes between patients with and without ictal EEG was discovered. Among MRI-negative patients, those with concordant ictal EEG had a significantly better outcome than those without ictal EEG (75.7% vs. 43.8%, p = 0.024). Further logistic regression analysis showed that concordant ictal EEG was an independent predictor for a favorable outcome (OR = 4.430, 95%CI 1.175-16.694, p = 0.028). Among MRI-positive patients, those with extra-temporal lesions and discordant ictal EEG results had a worse outcome compared to those without an ictal EEG result (44.7% vs. 68.8%, p = 0.005). Further logistic regression analysis showed that discordant ictal EEG was an independent predictor of worse outcome (OR = 0.387, 95%CI 0.186-0.807, p = 0.011) in these patients. Furthermore, our data indicated that the number of seizures was not associated with the concordance rates of the ictal EEG, nor the surgical outcomes. CONCLUSIONS: The value of ictal scalp EEG for epilepsy surgery varies widely among patients. A concordant ictal EEG predicts a good surgical outcome in MRI-negative patients, whereas a discordant ictal EEG predicts a poor postoperative outcome in lesional extratemporal lobe epilepsy.

TREM1 induces microglial ferroptosis through the PERK pathway in diabetic-associated cognitive impairment.

Ferroptosis is involved in neurodegenerative disorders including diabetes-associated cognitive impairment (DACI). As central immune cells, microglia have strong siderophilic properties. However, the role of iron deposition in microglia and the underlying regulatory mechanism remains unclear in DACI. Here, we established high glucose (HG) model in BV2/HMC3 cells and diabetes model in C57BL/6 J mice with HFD and STZ. Transmission Electron Microscopy, Western blot, assay kits of Fe2+, GSH/GSSG, MDA and ROS were carried out in vitro. Prussian blue staining, Western blot and immunofluorescence were implemented in vivo. Y-maze and novel object recognition were performed to assess cognitive performance. LP17 was used to inhibit TREM1 (triggering receptor expressed on myeloid cells 1) specifically in vivo and vitro. We found excessively deposited iron and significant reduction in antioxidants in hippocampal microglia of mice with DACI, concomitant with increased TREM1 (a microglia-specific inflammatory amplifier). Furthermore, LP17 (TREM1 specific inhibitor) ameliorated cognitive impairment caused by HFD/STZ through relieving iron accumulation and antioxidant inactivation. In vitro, ferroptosis was induced by HG in mice microglia-BV2 and human microglia-HMC3 cells, which could be blocked by a ferroptosis inhibitor-Fer-1 and LP17. Moreover, PERK pathway of endoplasmic reticulum stress was activated by HG, and then reversed by PERK inhibitor GSK2606414 and LP17 followed by improved ferroptosis in HG-cultured BV2. In summary, our results indicated that TREM1 effectively aggravates T2DM-associated microglial iron accumulation through the PERK pathway of ERS, which contributes to antioxidant inactivation and lipid peroxidation, eventually, massively boosted ROS result in microglial ferroptosis. The mechanism elucidation in our study may shed light on targeted therapy of DACI.