Electroencephalography microstates as novel functional biomarkers for insomnia disorder.

Background: Insomnia disorder (ID) is one of the most common mental disorders. Research on ID focuses on exploring its mechanism of disease, novel treatments and treatment outcome prediction. An emerging technique in this field is the use of electroencephalography (EEG) microstates, which offer a new method of EEG feature extraction that incorporates information from both temporal and spatial dimensions. Aims: To explore the electrophysiological mechanisms of repetitive transcranial magnetic stimulation (rTMS) for ID treatment and use baseline microstate metrics for the prediction of its efficacy. Methods: This study included 60 patients with ID and 40 age-matched and gender-matched good sleep controls (GSC). Their resting-state EEG microstates were analysed, and the Pittsburgh Sleep Quality Index (PSQI) and polysomnography (PSG) were collected to assess sleep quality. The 60 patients with ID were equally divided into active and sham groups to receive rTMS for 20 days to test whether rTMS had a moderating effect on abnormal microstates in patients with ID. Furthermore, in an independent group of 90 patients with ID who received rTMS treatment, patients were divided into optimal and suboptimal groups based on their median PSQI reduction rate. Baseline EEG microstates were used to build a machine-learning predictive model for the effects of rTMS treatment. Results: The class D microstate was less frequent and contribute in patients with ID, and these abnormalities were associated with sleep onset latency as measured by PSG. Additionally, the abnormalities were partially reversed to the levels observed in the GSC group following rTMS treatment. The baseline microstate characteristics could predict the therapeutic effect of ID after 20 days of rTMS, with an accuracy of 80.13%. Conclusions: Our study highlights the value of EEG microstates as functional biomarkers of ID and provides a new perspective for studying the neurophysiological mechanisms of ID. In addition, we predicted the therapeutic effect of rTMS on ID based on the baseline microstates of patients with ID. This finding carries great practical significance for the selection of therapeutic options for patients with ID.

Effects on resting-state EEG phase-amplitude coupling in insomnia disorder patients following 1 Hz left dorsolateral prefrontal cortex rTMS.

Despite burgeoning evidence for cortical hyperarousal in insomnia disorder, the existing results on electroencephalography spectral features are highly heterogeneous. Phase-amplitude coupling, which refers to the modulation of the low-frequency phase to a high-frequency amplitude, is probably a more sensitive quantitative measure for characterizing abnormal neural oscillations and explaining the therapeutic effect of repetitive transcranial magnetic stimulation in the treatment of patients with insomnia disorder. Sixty insomnia disorder patients were randomly divided into the active and sham treatment groups to receive 4 weeks of repetitive transcranial magnetic stimulation treatment. Behavioral assessments, resting-state electroencephalography recordings, and sleep polysomnography recordings were performed before and after repetitive transcranial magnetic stimulation treatment. Forty good sleeper controls underwent the same assessment. We demonstrated that phase-amplitude coupling values in the frontal and temporal lobes were weaker in Insomnia disorder patients than in those with good sleeper controls at baseline and that phase-amplitude coupling values near the intervention area were significantly enhanced after active repetitive transcranial magnetic stimulation treatment. Furthermore, the enhancement of phase-amplitude coupling values was significantly correlated with the improvement of sleep quality. This study revealed the potential of phase-amplitude coupling in assessing the severity of insomnia disorder and the efficacy of repetitive transcranial magnetic stimulation treatment, providing new insights on the abnormal physiological mechanisms and future treatments for insomnia disorder.

The potential of electroencephalography coherence to predict the outcome of repetitive transcranial magnetic stimulation in insomnia disorder.

BACKGROUND: It is unknown whether repetitive Transcranial Magnetic Stimulation (rTMS) could improve sleep quality by modulating electroencephalography (EEG) connectivity of insomnia disorder (ID) patients. Great heterogeneity had been found in the clinical outcomes of rTMS for ID. The study aimed to investigate the potential mechanisms of rTMS therapy for ID and develop models to predict clinical outcomes. METHODS: In Study 1, 50 ID patients were randomly divided into active and sham groups, and subjected to 20 sessions of treatment with 1 Hz rTMS over the left dorsolateral prefrontal cortex. EEG during awake, Polysomnography, and clinical assessment were collected and analyzed before and after rTMS. In Study 2, 120 ID patients were subjected to active rTMS stimulation and were then separated into optimal and sub-optimal groups due to the median of Pittsburgh Sleep Quality Index reduction rate. Machine learning models were developed based on baseline EEG coherence to predict rTMS treatment effects. RESULTS: In Study 1, decreased EEG coherence in theta and alpha bands were observed after rTMS treatment, and changes in theta band (F7-O1) coherence were correlated with changes in sleep efficiency. In Study 2, baseline EEG coherence in theta, alpha, and beta bands showed the potential to predict the treatment effects of rTMS for ID. CONCLUSION: rTMS improved sleep quality of ID patients by modulating the abnormal EEG coherence. Baseline EEG coherence between certain channels in theta, alpha, and beta bands could act as potential biomarkers to predict the therapeutic effects.

Functional connectivity density abnormalities and anxiety in primary insomnia patients.

Primary insomnia (PI) is strongly associated with emotional dysregulation. However, the neurobiological pathology of the association between PI and emotional dysregulation is limited. Previous studies have indicated an impact of PI on the emotional regulatory system, but the specificity of this finding remains to be confirmed. A sample of 27 primary insomnia patients (PIs) and 32 matched healthy controls (HCs) was recruited for this study. The functional connectivity density (FCD) was used to assess the spontaneous functional brain organization in PIs. Then, we identified whether the local (lFCD) and global FCD (gFCD) abnormalities can be the potential biomarker for emotion level in PIs. Our findings suggested that PIs exhibited higher levels of anxiety and depression, and the levels of anxiety and depression is associated with the insomnia severity. We also found that PIs showed both lower lFCD and gFCD in several regions (i.e. thalamus, anterior cingulate cortex (ACC), insula). Furthermore, the lower gFCD values of left ACC and right insula were associated with their anxiety level in PIs, which demonstrated their potential biomarker for anxiety in PIs. Our results demonstrated that the relationship between the insomnia severity and the anxiety level could be partially mediated by gFCD of the ACC and insula. The current study improved our understanding of the anxiety in PIs and provided helpful information for future therapeutic development for PIs.

Nobiletin promotes antioxidant and anti-inflammatory responses and elicits protection against ischemic stroke in vivo.

BACKGROUND: Post-ischemic oxidative stress and inflammation play pivotal roles in the pathogenesis of ischemic stroke and may represent therapeutic targets. Nobiletin (NOB) has been reported to elicit a variety of biological effects through its anti-oxidant and anti-inflammatory properties. Our previous study has demonstrated the beneficial effect of NOB in ischemic stroke, but the underlying mechanisms remain poorly defined. We therefore further investigated the role of NOB in cerebral ischemia and its potential mechanisms. METHODS: Adult male Sprague-Dawley rats were randomly assigned to five groups: Sham (sham-operated+0.05% Tween-80), permanent middle cerebral artery occlusion (pMCAO+0.9% saline), Vehicle (pMCAO+0.05% Tween-80), NOB-L (pMCAO+NOB 10mg/kg) and NOB-H (pMCAO+NOB 25mg/kg) groups. Rats were pre-administered intraperitoneally once daily for 3 days prior to ischemia and then received once again immediately after surgery. Neurological deficit, brain edema and infarct volume were evaluated at 24h after stroke. Immunohistochemistry, western blot and RT-qPCR were used to detect the expression of Nrf2, HO-1, SOD1, NF-κB and MMP-9. SOD1, GSH and MDA were measured by spectrophotometer. RESULTS: Compared with Vehicle group, neurological deficits and brain edema were relieved in NOB-H group, infarct volume was lessened in both NOB-L and NOB-H groups (P<0.05). NOB significantly increased the expression of Nrf2, HO-1, SOD1 and GSH, while decreased the levels of NF-κB, MMP-9 and MDA (P<0.05). CONCLUSION: NOB may have a neuroprotective effect on cerebral ischemia, and this protection may be through upregulating Nrf2, HO-1 and downregulating NF-κB expression.

Pretreatment by evodiamine is neuroprotective in cerebral ischemia: up-regulated pAkt, pGSK3ß, down-regulated NF-κB expression, and ameliorated BBB permeability.

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Evodiamine (Evo) has been proved to elicit a variety of biological effects through its anti-inflammatory property in the treatment of infectious disease, Alzheimer's disease and hypoxia-induced inflammatory response. Whether this protective effect applies to cerebral ischemic injury, we therefore investigated the potential neuroprotective role of Evo and the underlying mechanisms. Male Institute of Cancer Research (ICR) mice were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into five groups: Sham (sham-operated + 1% DMSO + 0.5% tween80), pMCAO (pMCAO + 0.9% saline), Vehicle (pMCAO + 1% DMSO + 0.5% tween80), Evo-L (Vehicle + Evo 50 mg/kg) and Evo-H (Vehicle + Evo 100 mg/kg) groups. Evo was administered intragastrically twice daily for 3 days, and once again 30 min before mouse brain ischemia was induced by pMCAO. Neurological deficit, brain water content and infarct size were measured at 24 h after stroke. The expression of pAkt, pGSK3ß, NF-κB and claudin-5 in ischemic cerebral cortex was analyzed by western blot and qRT-PCR. Compared with Vehicle group, Evo significantly ameliorated neurological deficit, brain water content and infarct size, upregulated the expression of pAkt, pGSK3ß and claudin-5, and downregulated the nuclear accumulation of NF-κB (P < 0.05). Evo protected the brain from ischemic damage caused by pMCAO; this effect may be through upregulation of pAkt, pGSK3ß and claudin-5, and downregulation of NF-κB expression.

Protective effect of naringenin in experimental ischemic stroke: down-regulated NOD2, RIP2, NF-κB, MMP-9 and up-regulated claudin-5 expression.

Inflammatory damage plays a pivotal, mainly detrimental role in cerebral ischemic pathogenesis and may represent a promising target for treatment. Naringenin (NG) has gained growing appreciation for its beneficial biological effects through its anti-inflammatory property. Whether this protective effect applies to cerebral ischemic injury, we therefore investigate the potential neuroprotective role of NG and the underlying mechanisms. Focal cerebral ischemia in male Sprague-Dawley rats was induced by permanent middle cerebral artery occlusion (pMCAO) and NG was pre-administered intragastrically once daily for four consecutive days before surgery. Neurological deficit, brain water content and infarct volume were measured at 24 h after stroke. Immunohistochemistry, Western blot and RT-qPCR were used to explore the anti-inflammatory potential of NG in the regulation of NOD2, RIP2 and NF-κB in ischemic cerebral cortex. Additionally, the activities of MMP-9 and claudin-5 were analyzed to detect NG's influence on blood-brain barrier. Compared with pMCAO and Vehicle groups, NG noticeably improved neurological deficit, decreased infarct volume and edema at 24 h after ischemic insult. Consistent with these results, our data also indicated that NG significantly downregulated the expression of NOD2, RIP2, NF-κB and MMP-9, and upregulated the expression of claudin-5 (P < 0.05). The results provided a neuroprotective profile of NG in cerebral ischemia, this effect was likely exerted by down-regulated NOD2, RIP2, NF-κB, MMP-9 and up-regulated claudin-5 expression.

Bicyclol upregulates transcription factor Nrf2, HO-1 expression and protects rat brains against focal ischemia.

UNLABELLED: Oxidative damage plays a detrimental role in the pathophysiology of cerebral ischemia and may represent a therapeutic target. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) controls the coordinated expression of the important antioxidant and detoxification genes through a promotor sequence termed the antioxidant response element. Bicyclol has been proved to elicit a variety of biological effects through its antioxidant and anti-inflammatory properties. But the underlying mechanisms are poorly understood. In this study, the role of bicyclol in cerebral ischemia and its potential mechanism were investigated. METHODS: Male Sprague-Dawley rats were randomly assigned to five groups: MCAO (middle cerebral artery occlusion), Vehicle (MCAO+0.5% sodium carboxymethylcellulose), By-L (Vehicle+bicyclol 50mg/kg), By-H (Vehicle+bicyclol 100mg/kg) and Sham operated groups. Bicyclol was administered intragastrically once a day for 3 consecutive days; after 1h of bicyclol pretreatment on the third day, rat ischemic stroke was induced by MCAO. Neurological deficit, infarct volume, and brain edema were detected at 24h after stroke. Western blot and RT-qPCR were used to measure the expression of Nrf2, HO-1 and SOD1. MDA was detected by the spectrophotometer. RESULTS: Compared with MCAO group, By-H group significantly ameliorated neurological deficit, lessened the infarct volume and brain edema, increased the expression of Nrf2, HO-1 and SOD1 (P<0.05), and decreased the content of MDA (P<0.05). CONCLUSIONS: Bicyclol protected the rat brain from ischemic damage caused by MCAO, and this effect may be through the upregulation of the transcription factor Nrf2 expression.

Neuroprotective effect of bicyclol in rat ischemic stroke: down-regulates TLR4, TLR9, TRAF6, NF-κB, MMP-9 and up-regulates claudin-5 expression.

BACKGROUND: Inflammatory damage aggravates the cerebral ischemic pathological process and may pave a new way for treatment. Bicyclol has been proved to elicit a series of biologic effects through its anti-inflammatory property in treating hepatitis and hepatic ischemic/reperfusion injury. Whether this protective effect applies to cerebral ischemic injury, we therefore investigated the potential neuroprotective role of bicyclol and the underlying mechanisms. METHODS: Male Sprague-Dawley rats were randomly assigned to five groups: permanent middle cerebral artery occlusion (pMCAO), Vehicle (pMCAO+0.5% sodium carboxymethylcellulose), By-L (Vehicle+bicyclol 50 mg/kg), By-H (Vehicle+bicyclol 100 mg/kg) and Sham operated group. Bicyclol was administered intragastrically once a day for 3 days, after 1h of bicyclol pretreatment on the third day; rat brain ischemia was induced by pMCAO. Neurological deficit, infarct volume, and brain edema were measured at 24 h after stroke. Immunohistochemistry, Western blot and real-time quantitative PCR were used to detect the expression of TLR4, TLR9, TRAF6, NF-κB and MMP-9, claudin-5. RESULTS: Compared with pMCAO group, bicyclol significantly ameliorated neurological deficit, decreased infarct volume and edema, and down-regulated the expression of TLR4, TLR9, TRAF6, NF-κB and MMP-9 (P<0.05). Meanwhile, the expression of claudin-5 was increased (P<0.05). CONCLUSIONS: Bicyclol has neuroprotective effect on cerebral ischemia, and this protection may be through down-regulating TLR4, TLR9, TRAF6, NF-κB, MMP-9 and up-regulating claudin-5 expression.

Nobiletin protects against cerebral ischemia via activating the p-Akt, p-CREB, BDNF and Bcl-2 pathway and ameliorating BBB permeability in rat.

There is cumulative evidence that the serine-threonine kinase Akt and its downstream nuclear transcription factor CREB are involved in neuronal survival and protection. The Akt activates and phosphorylates CREB at Ser133, resulting in the up-regulation of pro-survival CREB target genes such as BDNF and Bcl-2. Thus, Akt/CREB signaling pathway may be one propitious target for treatment of ischemic cerebral injury. Nobiletin (NOB) exhibits a wide spectrum of beneficial biological properties including anti-inflammatory, antioxidant, anti-carcinogenic actions and contributes to reverse learning impairment in Alzheimer's disease rat. However, little is currently known regarding the exact role of NOB in ischemic stroke. Here, we designed to evaluate its possible therapeutic effect on cerebral ischemia. Adult male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into five groups: Sham (sham-operated+0.05% Tween-80), MCAO (pMCAO+0.9% saline), Vehicle group (pMCAO+0.05% Tween-80), NOB-L (pMCAO+NOB 10 mg/kg) and NOB-H (pMCAO+NOB 25 mg/kg) groups. Rats were pre-administered intraperitoneally once daily for 3 days before surgery and then received once again immediately after surgery. Neurological deficit scores, brain water content and infarct volume were evaluated at 24 h after stroke. Additionally, the activities of Akt, CREB, BDNF, Bcl-2 and claudin-5 in ischemic brain cortex were analyzed by the methods of immunohistochemistry, western blot and RT-qPCR. Compared with Vehicle group, neurological deficits and brain edema were relieved in NOB-H group (P<0.05), infarct volume was lessened in both NOB-L and NOB-H groups (P<0.05) at 24 h after stroke. Immunohistochemistry, western blot and RT-qPCR analysis indicated that NOB dramatically promoted the activities of Akt, CREB, BDNF and Bcl-2 (P<0.05). Meanwhile, claudin-5 expression was also enhanced. On the basis of these findings, we concluded that NOB protected the brain from ischemic damage and it maybe through activating the Akt/CREB signaling pathway and ameliorating BBB permeability.

The protection by octreotide against experimental ischemic stroke: up-regulated transcription factor Nrf2, HO-1 and down-regulated NF-κB expression.

BACKGROUND: Inflammatory and oxidative damage play a pivotal role in cerebral ischemic pathogenesis and may represent a therapeutic target. Octreotide (OCT) has been proved to elicit a variety of biological effects through its anti-inflammatory and anti-oxidant properties in the treatment of severe acute pancreatitis and ischemia-reperfusion injury in retina and intestine. However little is known regarding the effect of OCT in ischemic stroke. Here, we designed this study to investigate the protective effect of OCT in ischemic stroke and explore the potential underlying mechanisms. METHODS: Male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into four groups: Sham (sham-operated), MCAO (pMCAO+0.9% saline), OCT-L (pMCAO+OCT 50µg/kg) and OCT-H (pMCAO+OCT 100µg/kg) groups. OCT was administered intraperitoneally immediately after stroke. Neurological deficit scores, infarct volume and brain water content were measured at 24h after stroke. Immunohistochemical staining and western blot were used to analyze the expressions of Nrf2, HO-1 and NF-κB. SOD and MDA were measured by spectrophotometer. RESULTS: Compared with MCAO group, OCT significantly alleviated neurological deficit, lessened infarct volume and brain edema (P<0.05), upregulated the expression of Nrf2, HO-1 and SOD (P<0.05), and decreased the expression of NF-κB and MDA (P<0.05). CONCLUSIONS: OCT protected the brain against cerebral ischemic damage; this effect may be through upregulation of transcription factor Nrf2, HO-1 and downregulation of NF-κB expression.