Alpha-Ketoglutarate Alleviates Neuronal Apoptosis Induced by Central Insulin Resistance through Inhibiting S6K1 Phosphorylation after Subarachnoid Hemorrhage

miR-93-5p impairs autophagy-lysosomal pathway via TET3 after subarachnoid hemorrhage

Intact autophagy-lysosomal pathway (ALP) in neuronal survival is crucial. However, it remains unclear whether ALP is intact after subarachnoid hemorrhage (SAH). Ten-eleven translocation (TET) 3 primarily regulates genes related to autophagy in neurons in neurodegenerative diseases. This study aims to investigate the role of TET3 in the ALP following SAH. The results indicate that the ALP is impaired after SAH, with suppressed autophagic flux and an increase in autophagosomes. This is accompanied by a decrease in TET3 expression. Activation of TET3 by α-KG can improve ALP function and neural function to some extent. Silencing TET3 in neurons significantly inhibited the ALP function and increased apoptosis. Inhibition of miR-93-5p, which is elevated after SAH, promotes TET3 expression. This suggests that the downregulation of TET3 after SAH is, at least in part, due to elevated miR-93-5p. This study clarifies the key role of TET3 in the functional impairment of the ALP after SAH. The preliminary exploration revealed that miR-93-5p could lead to the downregulation of TET3, which could be a new target for neuroprotective therapy after SAH.

Association Between Insulin Resistance Markers and Poor Prognosis in Patients With Acute Ischemic Stroke After Intravenous Thrombolysis

OBJECTIVES

This study aims to investigate the significance of insulin resistance markers in predicting poor prognosis in acute ischemic stroke (AIS) patients after intravenous thrombolysis and to establish the corresponding nomogram.

METHODS

From January 2019 to March 2023, the data of 412 patients with AIS who received intravenous alteplase thrombolytic therapy in the Affiliated Taizhou People's Hospital of Nanjing Medical University were selected. Patients were randomly divided into training groups (70%, 288 cases) and validation groups (30%, 124 cases). In the training group, multivariate logistic regression analysis was used to establish the best nomogram prediction model. The predictive ability of the nomogram was further evaluated by the area under the receiver operating characteristic curve, calibration curve, decision curve analysis, and reclassification analysis. Furthermore, the model was further validated in the validation set.

RESULTS

Multivariate logistic regression analysis showed that systolic blood pressure, diabetes, National Institutes of Health Stroke Scale score, triglyceride-glucose index, triglyceride-glucose-body mass index, ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol were associated with poor prognosis in AIS patients after intravenous thrombolysis ( P <0.05). Compared with conventional factors, the nomogram showed stronger prognostic ability, area under receiver operating characteristic curves were 0.948 (95% CI: 0.920-0.976, P <0.001) and 0.798 (95% CI: 0.747-0.849, P <0.001), respectively.

CONCLUSIONS

Triglyceride-glucose index, triglyceride-glucose-body mass index, and low-density lipoprotein cholesterol to high-density lipoprotein cholesterol levels upon admission can serve as markers for poor prognosis in AIS patients after intravenous thrombolysis. The nomogram enables a more accurate prediction of poor prognosis in AIS patients after intravenous thrombolysis.

Selective Activation of G Protein-Coupled Estrogen Receptor 1 (GPER1) Reduces ER Stress and Pyroptosis via AMPK Signaling Pathway in Experimental Subarachnoid Hemorrhage

Neuroinflammation is a critical pathogenic event following hemorrhagic stroke. Endoplasmic reticulum (ER) stress-induced apoptosis and nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3(NLRP3)-associated pyroptosis can contribute to the escalation of neuroinflammatory responses, leading to increased brain damage. G protein-coupled estrogen receptor 1(GPER1), as the most extensively characterized brain-derived estrogen, was reported to trigger neuroprotective effects. However, the anti-apoptotic and anti-pyroptotic effect of GPER1 activation and the underlying mechanism has not been fully elucidated. We established the experimental SAH model by intravascular perforation. The GPER1 selective agonist G1 was intravenously administered 1 h following SAH. For mechanistic exploration, the selective inhibitor of adenosine monophosphate-activated protein kinase (AMPK), dorsomorphin, was administered via intracerebroventricular injection 30 min prior to SAH induction. Post-SAH assessments included SAH grade, the short-term and long-term neurological outcomes, brain edema, cerebral blood flow, transmission electron microscopy (TEM), western blot (WB), ELISA, TUNEL staining, Fluoro-Jade C staining (FJC), and immunofluorescence staining. The expression of GPER1 was observed to elevate at 6 h and peaked at 24 h subsequent to SAH, predominantly co-localized with neurons. Post-treatment with G1 markedly ameliorated both the short-term and long-term neurological deficits of SAH mouse, as well as inhibiting the expression of neuronal ER stress-associated apoptotic proteins (i.e., CHOP, GRP78, Caspase-12, Cleaved Caspase-3, Bax, Bcl2) and pyroptosis-associated proteins (i.e., NLRP3, ASC, Cleaved Caspase-1). Additionally, our research revealed that inhibition of AMPK with dorsomorphin attenuated the neuroprotective effects of G1. This was accompanied by modifications in the molecular pathways associated with ER stress-induced apoptosis and pyroptosis. These data herein elucidated that GPER1 exerted neuroprotective effects by mitigating neuroinflammation in an AMPK-dependent manner, which modulates neuronal ER stress-associated apoptosis and pyroptosis. Boosting the anti-apoptotic and anti-pyroptotic effect by activating GPER1 may be an efficient treatment strategy for SAH patients.

Triglyceride Glucose Index and Prognosis of Patients with Subarachnoid Hemorrhage

OBJECTIVE

The triglyceride glucose (TyG) index is regarded as a reliable alternative indicator for measuring insulin resistance. We investigated the association between the prognosis of patients with subarachnoid hemorrhage (SAH)and the TyG index, explored the potential of the TyG index as a new biomarker for forecasting the outcomes of SAH patients, and explored independent risk factors for predicting the condition of SAH patients.

METHODS

A retrospective analysis was performed of patients who were admitted to a single center due to SAH. Differences in clinical data and correlation between laboratory indexes, disease severity score on admission, and prognosis score were compared between the 2 groups. The study employed multivariate logistic regression analysis to examine the independent influencing aspects of Glasgow Outcome Scale score. The receiver operating characteristic curve was drawn and the area under the curve (AUC) calculated to predict the best cutoff value of the degree of neurological impairment in patients with SAH.

RESULTS

Univariate analysis showed that Glasgow Coma Scale score (86.3% vs. 12.0%, P < 0.001), Hunt-Hess grade (88.2% vs. 15.7%, P < 0.001), white blood cell count (11.20 [7.9, 15.2] vs. 9.1 [7.0, 12.2], P = 0.027), and TyG index (1.49 [1.40, 1.59] vs. 1.16 [1.06, 1.27], P < 0.001) were statistically significantly different. Multivariate analysis showed that TyG index, Hunt-Hess grade, and GCS score were independent risk factors for poor prognosis.

CONCLUSIONS

Patients with SAH may benefit from using the TyG index as a predictive method. In our clinical practice, the TyG index is beneficial for managing diseases and making decisions. More research is required to determine if improved TyG index control would lead to better clinical results in the future.

Sirtuins as Potential Targets for Neuroprotection: Mechanisms of Early Brain Injury Induced by Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a prevalent cerebrovascular disease with significant global mortality and morbidity rates. Despite advancements in pharmacological and surgical approaches, the quality of life for SAH survivors has not shown substantial improvement. Traditionally, vasospasm has been considered a primary contributor to death and disability following SAH, but anti-vasospastic therapies have not demonstrated significant benefits for SAH patients' prognosis. Emerging studies suggest that early brain injury (EBI) may play a crucial role in influencing SAH prognosis. Sirtuins (SIRTs), a group of NAD + -dependent deacylases comprising seven mammalian family members (SIRT1 to SIRT7), have been found to be involved in neural tissue development, plasticity, and aging. They also exhibit vital functions in various central nervous system (CNS) processes, including cognition, pain perception, mood, behavior, sleep, and circadian rhythms. Extensive research has uncovered the multifaceted roles of SIRTs in CNS disorders, offering insights into potential markers for pathological processes and promising therapeutic targets (such as SIRT1 activators and SIRT2 inhibitors). In this article, we provide an overview of recent research progress on the application of SIRTs in subarachnoid hemorrhage and explore their underlying mechanisms of action.

Hydrogen inhalation therapy regulates lactic acid metabolism following subarachnoid hemorrhage through the HIF-1α pathway

The neuroprotective effects of hydrogen have been demonstrated, but the mechanism is still poorly understood. In a clinical trial of inhaled hydrogen in patients with subarachnoid hemorrhage (SAH), we found that hydrogen reduced the accumulation of lactic acid in the nervous system. There are no studies demonstrating the regulatory effect of hydrogen on lactate and in this study we hope to further clarify the mechanism by which hydrogen regulates lactate metabolism. In cell experiments, PCR and Western Blot showed that HIF-1α was the target related to lactic acid metabolism that changed the most before and after hydrogen intervention. HIF-1α levels were suppressed by hydrogen intervention treatment. Activation of HIF-1α inhibited the lactic acid-lowering effect of hydrogen. We have also demonstrated the lactic acid-lowering effect of hydrogen in animal studies. Our work clarifies that hydrogen can regulate lactate metabolism via the HIF-1αpathway, providing new insights into the neuroprotective mechanisms of hydrogen.

Molecular mechanisms of neuronal death in brain injury after subarachnoid hemorrhage

Subarachnoid haemorrhage (SAH) is a common cerebrovascular disease with high disability and mortality rates worldwide. The pathophysiological mechanisms involved in an aneurysm rupture in SAH are complex and can be divided into early brain injury and delayed brain injury. The initial mechanical insult results in brain tissue and vascular disruption with hemorrhages and neuronal necrosis. Following this, the secondary injury results in diffused cerebral damage in the peri-core area. However, the molecular mechanisms of neuronal death following an aneurysmal SAH are complex and currently unclear. Furthermore, multiple cell death pathways are stimulated during the pathogenesis of brain damage. Notably, particular attention should be devoted to necrosis, apoptosis, autophagy, necroptosis, pyroptosis and ferroptosis. Thus, this review discussed the mechanism of neuronal death and its influence on brain injury after SAH.

Insulin resistance in ischemic stroke: Mechanisms and therapeutic approaches

The pathological condition of insulin resistance prevents the neuroprotective effects of insulin. Numerous studies have demonstrated that insulin resistance, as an independent risk factor for ischemic stroke, accelerates the formation of thrombosis and promotes the development of atherosclerosis, both of which are major mechanisms of ischemic stroke. Additionally, insulin resistance negatively affects the prognosis of patients with ischemic stroke regardless of whether the patient has diabetes, but the mechanisms are not well studied. We explored the association between insulin resistance and the primary mechanisms of brain injury in ischemic stroke (inflammation, oxidative stress, and neuronal damage), looking for potential causes of poor prognosis in patients with ischemic stroke due to insulin resistance. Furthermore, we summarize insulin resistance therapeutic approaches to propose new therapeutic directions for clinically improving prognosis in patients with ischemic stroke.