An extra-erythrocyte role of haemoglobin body in chondrocyte hypoxia adaption.

Although haemoglobin is a known carrier of oxygen in erythrocytes that functions to transport oxygen over a long range, its physiological roles outside erythrocytes are largely elusive1,2. Here we found that chondrocytes produced massive amounts of haemoglobin to form eosin-positive bodies in their cytoplasm. The haemoglobin body (Hedy) is a membraneless condensate characterized by phase separation. Production of haemoglobin in chondrocytes is controlled by hypoxia and is dependent on KLF1 rather than the HIF1/2α pathway. Deletion of haemoglobin in chondrocytes leads to Hedy loss along with severe hypoxia, enhanced glycolysis and extensive cell death in the centre of cartilaginous tissue, which is attributed to the loss of the Hedy-controlled oxygen supply under hypoxic conditions. These results demonstrate an extra-erythrocyte role of haemoglobin in chondrocytes, and uncover a heretofore unrecognized mechanism in which chondrocytes survive a hypoxic environment through Hedy.

Effects of hyperbaric oxygen pretreatment on brain antioxidant capacity in rats with decompression sickness.

OBJECTIVE: Decompression sickness (DCS) causes serious brain hypoxic-ischemic injury. This experiment was designed to observe whether hyperbaric oxygen (HBO2) pretreatment played a neuroprotective effect in decompression sickness rat models and to explore the mechanism of protective effects. METHODS: Sprague-Dawley (SD) male rats were pretreated with HBO2 and then underwent decompression to establish the DCS rat model. Antioxidant capacities were evaluated by detecting peroxides (GPx), superoxide dismutase (SOD), catalase (CAT) activity and malondialdehyde (MDA) content in brains. The levels of metal elements manganese (Mn), zinc (Zn), iron (Fe) and magnesium (Mg) in brain tissues were assessed by flame atomic absorption spectrometry. Necrosis and apoptosis of neurons were assessed by H-E staining and immunohistochemical staining. RESULTS: HBO2 pretreatment reduced the degree of necrosis and apoptosis in brain tissues of decompression sickness rat models. In addition, HBO2 pretreatment increased GPx, SOD and CAT activities and reduced MDA accumulation. It also increased the content of Mn, Zn, Fe and Mg in brain tissue, which are all related to free radical metabolism. CONCLUSION: These results suggested that HBO2 pretreatment has protective effects on brain injury of rats with decompression sickness. The mechanism of the protective effects may be related to reducing oxidative damage by affecting metal elements in vivo.

BKCa compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats.

Previous studies have demonstrated cardiac and vascular remodeling induced by microgravity exposure. Yet, as the most important branch of vasculatures circulating the heart, the coronary artery has been seldomly studied about its adaptations under microgravity conditions. Large-conductance Ca2+-activated potassium channel (BKCa) and the Ras homolog family member A (RhoA)/Rho kinase (ROCK) pathway play key roles in control of vascular tone and mediation of microgravity-induced vascular adjustments. Therefore, we investigated the adaptation of coronary vasoreactivity to simulated microgravity and the role of BKCa and the RhoA/ROCK pathway in it. Four-week-old hind-limb unweighted (HU) rats were adopted to simulate effects of microgravity. Right coronary artery (RCA) constriction was measured by isometric force recording. The activity and expression of BKCa and the RhoA/ROCK pathway were examined by Western blot, patch-clamp recordings, and immunoprecipitation. We found HU significantly decreased RCA vasoconstriction to KCl, serotonin, and U-46619, but increased protein expression and current densities of BKCa, inhibition of which by iberiotoxin (IBTX) further decreased RCA vasoconstriction (P < 0.05). Expression of RhoA and ROCK as well as active RhoA and phosphorylation of myosin light chain (MLC) at Ser19 and MLC phosphatase target-1 at Thr696 were significantly increased by HU, and ROCK inhibitor Y-27632 exerted greater suppressing effect on HU RCA vasoconstriction than that of control (P < 0.05). BKCa opener NS1619 increased HU RCA vasoconstriction, which was blocked by both RhoA and ROCK inhibitor, similar to the effect of IBTX. These results indicate that HU impairs coronary vasoconstriction but enhances BKCa activity acting as a protective mechanism avoiding excessive decrease of coronary vasoreactivity through activation of the RhoA/ROCK pathway.-Wu, Y., Yue, Z., Wang, Q., Lv, Q., Liu, H., Bai, Y., Li, S., Xie, M., Bao, J., Ma, J., Zhu, X., Wang, Z. BKCa compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats.

Hyperbaric oxygen treatment mitigates liver damage in mice with noise exposure.

Noise exposure relates to various pathological disorders including liver damage, preventive measures of which are being demanded. Hyperbaric oxygen treatment (HBOT), as a non-invasive procedure, exerts convincing therapeutic potency on multiple liver diseases. The efficacy of HBOT in mitigating noise induced liver damage (NILD) and associated mechanisms would be elucidated here. Mice were subject to broad band noise (20-20k Hz, 90-110 dB) for 5 days by 3 hours/day. HBOT with 2.5 atmosphere absolute (ata) was employed before noise exposure. Morphology of liver tissue was examined by hematoxylin-eosin (HE) staining. Oil Red O (ORO), transferase-mediated dUTP nick end labelling (TUNEL) test and western blot were utilized to detect lipid accumulation, apoptotic cells and protein expression, respectively. Ceramide (Cer) level was assayed by immunohistochemistry (IHC) analysis. With noise exposure, conspicuous structural derangement and lipid deposition occurred in liver tissue of mice, which was alleviated significantly by the application of HBOT. Meanwhile, HBOT reduced the proportion of apoptotic hepatocytes, restraining the superoxide production in noise exposed mice. In view of underlying mechanisms, noise enhanced the acid sphingomyelinase (ASM) protein expression and the Cer generation in liver tissue of mice which was reversed substantially by HBOT. Altogether, HBOT ameliorates the structural and functional derangement of liver by neutralizing the ASM/Cer pathway in noise exposed mice.

Acid sphingomyelinase mediates the noise-induced liver disorder in mice.

Noise-induced structural and functional disorder of the liver has been realized, but the underlying mechanism remains to be characterized, which has limited the introduction of precautious measures. Over-activation of acid sphingomyelinase (ASM)/ceramide (Cer) pathway takes centre stage in hepatocyte injury entailed by various stimulus. We aimed to investigate whether it mediated the noise elicited liver disorder on infrastructure, lipid metabolism, apoptosis, and oxidative stress. Mice were exposed to broad band noise (20-20k Hz, 90-110 dB) for 1, 3, 5 or 7 days by 3 hr/d. Doxepin hydrochloride (DOX), an ASM inhibitor was given by 5 mg/kg/d gavage. We showed that 5 or 7 days intense, broad band noise exposure caused significant infrastructure derangement and lipid droplets storage in hepatocytes. The content of cholesterol, free fatty acids or triglyceride was increased significantly in liver tissue upon noise stimulation. Moreover, the noise promoted apoptosis and superoxide generation in hepatocytes significantly, enhancing activity of aspartate aminotransferase (AST) or alanine amino transferase (ALT) in serum. Acid sphingomyelinase activity and Cer generation in liver tissue were elevated by noise exposure, which was normalized with DOX administrated. Accordingly, DOX alleviated steatosis, apoptosis, oxidative stress and enzymatic change in hepatocytes or serum of noise exposed mice substantially. In summary, our results suggest the ASM/Cer pathway contributes to the broad band noise elicited liver damage in mice.

Hyperbaric Oxygen Treatment Ameliorates Hearing Loss and Auditory Cortex Injury in Noise Exposed Mice by Repressing Local Ceramide Accumulation.

Noise-induced hearing loss (NIHL) relates closely to auditory cortex (AC) injury, so countermeasures aiming at the AC recovery would be of benefit. In this work, the effect of hyperbaric oxygen treatment on NIHL was elucidated, which was imposed on mice before (HBOP), during (HBOD) or after (HBOA) noise exposure. Morphology of neurons was assayed by hematoxylin-eosin or Nissl staining. Ceramide (Cer) level was measured through immunohistochemistry analysis. Apoptotic neurons were counted using transferase-mediated dUTP nick end labeling (TUNEL) staining. We demonstrated that the intense, broad band noise raised the threshold of auditory brainstem response, evoked neuronal degeneration or apoptosis and triggered the Cer accumulation in AC, all of which were restored significantly by HBOP, but not HBOD or HBOA. Cer over-generation reversed the advantages of HBOP significantly, while its curtailment recapitulated the effect. Next, noise exposure raised the superoxide or malondialdehyde (MDA) production which was blocked by HBOP or Cer repression. Oxidative control not only attenuated the hearing loss or neurodegeneration but, in turn, reduced the Cer formation significantly. In summary, mutual regulation between Cer and oxidative stress underlies the HBOP's curative effect on hearing loss and neuronal damage in noise-exposed mice.

Acid sphingomyelinase/ceramide regulates carotid intima-media thickness in simulated weightless rats.

Structural adaptation of arteries to weightlessness might lower the working ability or even threaten the physical health of astronauts, but the underlying mechanism is unclear. Acid sphingomyelinase (ASM) catalyzes ceramide (Cer) generation controlling arterial remodeling through multiple signaling pathways. In the present study, we aimed to investigate the contribution of ASM/Cer to the changes of common carotid artery intima-media thickness (CIMT) induced by simulated weightlessness. Hindlimb-unloaded tail-suspended (HU) rats were used to simulate the effect of weightlessness. Morphology of the carotid artery (CA) was examined by hematoxylin-eosin staining. Protein content of ASM or proliferating cell nuclear antigen (PCNA) was detected by Western blot. Cer level was measured by immunohistochemistry analysis. Apoptosis events were observed by transferase-mediated dUTP nick end labeling (TUNEL) staining. During 4 weeks of tail suspension, CIMT was increased gradually in HU but not in their synchronous control rats (P < 0.05). Correspondingly, the CA of HU rats had a lower apoptosis and higher proliferation of vascular smooth muscle cells (VSMCs). As compared to the control, both ASM protein expression and Cer content were reduced significantly in CA of HU rats (P < 0.05), incubation of which with permeable Cer reversed the changes in apoptosis and proliferation substantially. Furthermore, when the ASM protein content as well as Cer level in CA of control rats was diminished by using an ASM inhibitor, an increase of CIMT along with reduced apoptosis and enhanced proliferation of VSMCs was found. Our results suggest that by controlling the balance between apoptosis and proliferation, ASM/Cer plays an important role in the regulation of CIMT during simulated weightlessness.

Contribution of p62 to Phenotype Transition of Coronary Arterial Myocytes with Defective Autophagy.

BACKGROUND: Autophagy disorder contributes to dedifferentiation of arterial smooth muscle cells, but the mechanisms are poorly understood. Here, we sought to investigate the role of scaffolding adaptor p62/SQSTM1 (p62) in phenotype switching of mouse coronary arterial myocytes (CAMs) induced by CD38 gene deficiency or lysosomal dysfunction which blocks autophagic flux in the cells. METHODS: Protein expression was measured by western blot analysis and immunofluorescent staining. Cell cycle and proliferation rate were analyzed by flow cytometry and MTS assay respectively. mRNA abundance was tested by qRT-PCR. RESULTS: CD38 gene deficiency or bafilomycin A1 (baf), a selective lysosomal inhibitor treatment increased proliferation rate and vimentin expression in CAMs which was prevented by p62 gene silencing. Cell percentage in G₂/M and G₀/G₁ phase was decreased and increased by CD38 deficiency or baf treatment, respectively which was accompanied by accrual of cyclin-dependent kinase 1 (CDK1) protein. Although free ubiquitin content was increased, the colocalization of it to CDK1 was markedly decreased in CD38-/- or baf treated CAMs. Furthermore, the changes in both cell cycle and CDK1 ubiquitinylation could be restored by p62 gene silencing. CONCLUSION: The results suggest in CD38-/- or baf treated CAMs, p62 accumulation promotes phenotype transition and proliferation by accelerating cell cycle progress through G₂/M which might relate to the compromised ubiquitinylation and degradation of CDK1.

Caveolae Depletion Contributes to Vasorelaxant Effects of Chenodeoxycholic Acid.

BACKGROUND/AIMS: High concentration of bile acids (BAs) induces hydrophobicity-dependent vasorelaxtant effects with hydrophobic BAs showing greater responses than hydrophilic BAs, of which the underlying mechanisms are still unclear. Caveolae are invaginations on membranes of endothelial cells (ECs) entraping endothelial nitric oxide synthase (eNOS) to prevent its activation, which plays a critical role in regulation of vascular function. The purpose of the present study was to investigate the role of caveolae in vasorelaxant effects of BAs. METHODS: Chenodeoxycholic acid (CDCA) and cholic acid (CA) were used to represent hydrophobic and hydrophilic BA, respectively. Vascular responses of abdominal aorta were measured by isometric force recording. Morphology of caveolae was examined by transmission electron microscopy. Protein expression of total eNOS (t-eNOS) or phosphorylated eNOS (p-eNOS) was determined by Western blot. Nitric oxide (NO) content was observed by fluorometric assay. RESULTS: We demonstrated that CDCA as well as Methyl-ß-cyclodextrin (MCD), a commonly used reagent for cholesterol depletion, reduced potassium chloride (KCl)- or phenylephrine (PE)-elicited vasoconstriction (P < 0.05), and enhanced acetylcholine (Ach)-elicited vasodilatation (P < 0.05) in endothelium-intact abdominal aorta but not in endothelium-denuded or CA-treated vessels. CDCA and MCD, but not CA significantly disrupted caveolae structure on ECs of abdominal aorta which was recovered by cholesterol incubation (P < 0.05). Protein expression of t-eNOS was significantly decreased (P < 0.05), and that of p-eNOS together with NO content was significantly increased in CDCA- and MCD- but not CA-treated vessels (P < 0.05) as compared with vehicle. The effect was reversed by either endothelium-denudation or cholesterol replenishment. Moreover, with cholesterol incubation, no significant differences were found in vascular responses among CDCA-, CA- or vehicle-treated vessels. CONCLUSION: These results indicate that CDCA diminishes caveolae on ECs of abdominal aorta promoting eNOS phosphorylation and NO production which contributes to its vasorelaxtant effect.

Effects of hyperbaric oxygen on hippocampal neuronal apoptosis in rats with acute carbon monoxide poisoning.

INTRODUCTION: Acute carbon monoxide (CO) poisoning causes serious health problems such as neuropsychological sequelae. This study aimed to investigate neuronal apoptosis and the effects of hyperbaric oxygen (HBO2) on different regions of the rat hippocampus after CO poisoning. METHODS: 90 mature male Sprague Dawley rats were randomly divided into three groups: the normal control group (NC group), the acute carbon monoxide-poisoned group (CO group) and the hyperbaric oxygen treatment group (HBO2 group). CO exposure included 0, 1, 3, 7, 14 and 21 treatment days, one exposure on the first day, and sacrifice on each of the following days. HBO2 exposure included treatment for 0, 1, 3, 7, 14 and 21 days, daily treatment after CO exposure, and sacrifice after the last HBO2 treatment on each of those days. Hematoxylin-eosin staining, immunohistochemical staining, immunofluorescence staining, and western blot analysis were performed to detect apoptosis in brain tissue samples. RESULTS: MMP-9 and caspase-3 were prominently increased by CO exposure and inhibited by HBO2 in the CA3 region in the hippocampus at one, three and seven days (immunohistochemical staining [IHC]: P ⟨ 0.05). Neu N and the ratio of Bcl-2/ BAX were prominently decreased by CO exposure and rescued by HBO2 in the CA3 region after seven days of treatment (IHC: P ⟨ 0.05). CONCLUSION: These findings indicated that neuronal apoptosis in the rat hippocampus could be induced by acute CO exposure, especially in the CA3 region. HBO2 could effectively inhibit neuronal apoptosis, especially in the CA3 region after seven days of treatment. The application of HBO2 to inhibit MMP-9 and apoptosis may contribute to brain recovery after acute CO poisoning.

RNA sequencing analysis reveals new findings of hyperbaric oxygen treatment on rats with acute carbon monoxide poisoning.

OBJECTIVE: To elucidate the altered gene network in the brains of carbon monoxide (CO) poisoned rats after treatment with hyperbaric oxygen (HBO2). METHODS: RNA sequencing (RNA-seq) analysis was performed to examine differentially expressed genes (DEGs) in brain tissue samples from nine male rats: a normal control group; a CO poisoning group; and an HBO2 treatment group (three rats/group). Reverse transcription polymerase chain reaction (RT-PCR) and real-time quantitative PCR were used for validation of the DEGs in another 18 male rats (six rats/group). RESULTS: RNA-seq revealed that two genes were upregulated (4.18 and 8.76 log to the base 2 fold change) (p⟨0.05) in the CO-poisoned rats relative to the control rats; two genes were upregulated (3.88 and 7.69 log to the base 2 fold change); and 23 genes were downregulated (3.49-15.12 log to the base 2 fold change) (p⟨0.05) in the brains of the HBO2-treated rats relative to the CO-poisoned rats. Target prediction of DEGs by gene network analysis and analysis of pathways affected suggested that regulation of gene expressions of dopamine metabolism and nitric oxide (NO) synthesis were significantly affected by CO poisoning and HBO2 treatment. Results of RT-PCR and real-time quantitative PCR indicated that four genes (Pomc, GH-1, Pr1 and Fshß) associated with hormone secretion in the hypothalamic-pituitary system have potential as markers for prognosis of CO. CONCLUSION: This study is the first RNA-seq analysis profile of HBO2 treatment on rats with acute CO poisoning. It concludes that changes of hormone secretion in the hypothalamic-pituitary system, dopamine metabolism and NO synthesis involved in brain damage and behavior abnormalities after CO poisoning and HBO2 therapy may regulate these changes.

Caveolae regulate vasoconstriction of conduit arteries to angiotensin II in hindlimb unweighted rats.

Weightlessness induces the functional remodelling of arteries, but the changes to angiotensin II (Ang II)-elicited vasoconstriction and the underlying mechanism have never been reported. Caveolae are invaginations of the cell membrane crucial for the contraction of vascular smooth muscle cells, so we investigated the adaptation of Ang II-elicited vasoconstriction to simulated weightlessness and the role of caveolae in it. The 4 week hindlimb unweighted (HU) rat was used to simulate the effects of weightlessness. Ang II-elicited vasoconstriction was measured by isometric force recording. The morphology of caveolae was examined by transmission electron microscope. The binding of the angiotensin II type 1 receptor (AT1 ) and caveolin-1 (cav-1) was examined by coimmunoprecipitation and Western blot. We found that the maximal developing force (E(max)) of Ang II-elicited vasoconstriction was decreased in abdominal aorta by 30.6%, unchanged in thoracic aorta and increased in carotid artery by 17.9% after HU, while EC50 of the response was increased in all three arteries (P < 0.05). AT1 desensitization upon activation was significantly reduced by HU in all three arteries, as was the number of caveolae (P < 0.05). Furthermore, Ang II promoted the binding of AT1 and cav-1 significantly in control but not HU arteries. Both the number of caveolae and the binding of AT1 and cav-1 in HU arteries were restored by cholesterol pretreatment which also reinstated the change in EC50 as well as the level of AT1 desensitization. These results indicate that modified caveolae in vascular smooth muscle cells could interfere with the binding of AT1 and cav-1 mediating the adaptation of Ang II-elicited vasoconstriction to HU.

Simulated microgravity promotes monocyte adhesion to rat aortic endothelium via nuclear factor-κB activation.

Microgravity-induced vascular remodelling may play an important role in post-spaceflight orthostatic intolerance. In this study, we aimed to investigate the effects of simulated microgravity on monocyte adhesion to aortic endothelium in hindlimb unweighted rats and to elucidate the underlying mechanisms associated with this event. Sprague-Dawley rats were subjected to 4-week hindlimb unweighting to simulate microgravity. The recruitment of monocytes to the abdominal aorta was investigated by en face immunofluorescence staining and monocyte binding assays. The expression of the adhesion molecules E-selectin and vascular cell adhesion molecule-1 as well as the cytokine monocyte chemoattractant protein (MCP)-1 was evaluated by immunohistochemical staining, western blot, and quantitative reverse transcription polymerase chain reaction analyses. Additionally, nuclear factor-κB (NF-κB) activation and the messenger RNA expression levels of E-selectin, vascular cell adhesion molecule-1, and MCP-1 were assessed with the administration of an NF-κB inhibitor, pyrrolidine dithiocarbamate. Results showed that simulated microgravity significantly increased monocyte recruitment to the aortic endothelium, protein expression of E-selectin and MCP-1, and NF-κB activation in the abdominal aorta of rats. Pyrrolidine dithiocarbamate treatment not only significantly inhibited NF-κB activity but also reduced the messenger RNA levels of E-selectin, vascular cell adhesion molecule-1, and MCP-1 as well as monocyte recruitment in the abdominal aorta of hindlimb unweighted rats. These results suggest that simulated microgravity increases monocyte adhesion to rat aortic endothelium via the NF-κB-mediated expression of the adhesion molecule E-selectin and the cytokine MCP-1. Therefore, an NF-κB-mediated inflammatory response may be one of the cellular mechanisms responsible for arterial remodelling during exposure to microgravity.

Jeavons syndrome in China.

OBJECTIVES: Jeavons syndrome (JS) is one of the underreported epileptic syndromes and is characterized by eyelid myoclonia (EM), eye closure-induced seizures or electroencephalography (EEG) paroxysms, and photosensitivity. In the Western populations, it has been reported to be characterized by focal posterior, occipital predominant epileptiform discharges (OPEDs) or frontal predominant epileptiform discharges (FPEDs) followed by generalized EDs in both interictal and ictal EEG recordings. However, it is not clear if there are different clinical manifestations between OPEDs and FPEDs. The clinical and electrographic presentations in the Chinese population are largely unknown. Here, we report the clinical and electroencephalographic features of 50 Chinese patients with JS and evaluate for the presence of different clinical features between patients with OPEDs and patients with FPEDs. METHODS: We identified 50 cases who met the Jeavons syndrome criteria from 4230 patients with epilepsy at Xijing Hospital, Xi'an, China from the period of January 2010 to November 2011. These patients underwent long-term 24-hour video-EEG recording. Brain imaging was performed using magnetic resonance imaging (MRI) or computerized tomography (CT). Webster IQ testing was performed to determine intellectual development. We reviewed and described the interictal abnormalities, ictal EEG pattern, and demographic, clinical, and neuroimaging findings of these 50 Chinese patients in Xi'an. We divided the 50 patients into two groups according to the predominance of EDs and analyzed their clinical features. RESULTS: Twenty-five of these 50 patients were male. Twenty-two out of 32 patients in the group with FPEDs were male, and 3/18 patients in the group with OPEDs were male. The median age of EMA-EM onset in FPEDs was 8years and that in OPEDs was 5.8years. Eyelid myoclonia occurred in all the 50 patients. Twenty-one out of 32 patients in the group with FPEDs had EM with absences, and 14/32 of them had EM with eyeball rolling up. Two out of 18 patients in the group with OPEDs had EM with absences, and only 1 of 18 had EM with eyeball rolling up. CONCLUSION: Eyelid myoclonia with or without absences or JS diagnosis is easily missed and underreported in China. As an IGE, either the frontal or the occipital lobe may initiate generalized spike-and-wave discharges (GSWDs) and generalized seizures (GSs). There may be two subtypes of JS with distinctive clinical and electroencephalogrphic features: a predominantly male group with frontal predominant epileptiform discharges, eyelid myoclonia, and eyes rolling up and a predominantly female group with occipital predominant epileptiform discharges with eyelid myoclonia alone.

Simulated microgravity induces an inflammatory response in the common carotid artery of rats.

Post-spaceflight orthostatic intolerance is one of the most important adverse effects after exposure to space microgravity, and there are still no effective countermeasures. It has been considered that arterial remodeling may play an important role in the occurrence of post-spaceflight orthostatic intolerance, but the cellular mechanisms remain unknown. In this study, we investigated whether an inflammatory response exists in the common carotid artery of rats exposed to simulated microgravity. For this, Sprague-Dawley rats were subjected to 4 weeks of hindlimb unweighting to simulate microgravity. The expression levels of the adhesion molecules E-selectin and vascular cell adhesion molecule-1 (VCAM-1), and the cytokine monocyte chemoattractant protein-1 (MCP-1) in the common carotid artery of simulated microgravity rats were evaluated by immunohistochemical staining, quantitative RT-PCR, and Western blot analyses. The recruitment of monocytes in the common carotid artery of rats exposed to simulated microgravity was investigated by en face immunofluorescence staining and monocyte binding assays. Our results provided convincing evidence that there is an inflammatory response in the common carotid artery of rats exposed to simulated microgravity. Our work suggests that the inflammatory response may be a novel cellular mechanism that is responsible for the arterial remodeling that occurs during exposure to microgravity.

Machine learning-Based model for prediction of Narcolepsy Type 1 in Patients with Obstructive Sleep Apnea with Excessive Daytime Sleepiness.

Background: Excessive daytime sleepiness (EDS) forms a prevalent symptom of obstructive sleep apnea (OSA) and narcolepsy type 1 (NT1), while the latter might always be overlooked. Machine learning (ML) models can enable the early detection of these conditions, which has never been applied for diagnosis of NT1. Objective: The study aimed to develop ML prediction models to help non-sleep specialist clinicians identify high probability of comorbid NT1 in patients with OSA early. Methods: Totally, clinical features of 246 patients with OSA in three sleep centers were collected and analyzed for the development of nine ML models. LASSO regression was used for feature selection. Various metrics such as the area under the receiver operating curve (AUC), calibration curve, and decision curve analysis (DCA) were employed to evaluate and compare the performance of these ML models. Model interpretability was demonstrated by Shapley Additive explanations (SHAP). Results: Based on the analysis of AUC, DCA, and calibration curves, the Gradient Boosting Machine (GBM) model demonstrated superior performance compared to other machine learning (ML) models. The top five features used in the GBM model, ranked by feature importance, were age of onset, total limb movements index, sleep latency, non-REM (Rapid Eye Movement) sleep stage 2 and severity of OSA. Conclusion: The study yielded a simple and feasible screening ML-based model for the early identification of NT1 in patients with OSA, which warrants further verification in more extensive clinical practices.

Tongue Biting Event in Patients with Sleep-Related Facial Mandibular Myoclonus: A Case Series Study.

Background: Sleep-related facial mandibular myoclonus (SRFMM) remains rare in clinical practice. The aim of this study was to provide a comprehensive understanding of the electroclinical manner, therapeutic regimen, and prognosis of SRFMM. Methods: Twenty-three patients who were diagnosed with SRFMM by clinical manifestation, video-electroencephalography (EEG) and electromyography over bilateral masseter and temporalis muscles were enrolled. Clinical and electrophysiological evaluation as well as follow-up information were recorded and analyzed. Results: The cohort involved 4 infants and 19 adults with a mean onset age of 43.5 years for SRFMM, among whom 19 were male. Twenty-one patients complained of tongue injuries and disturbed night-time sleep. SRFMM in 4 patients were ascribed to oral aripiprazole, brainstem ischemia and brain trauma. In 62 SRFMM episodes, 93.5% occurred in NREM sleep and 6.5% in REM sleep, and all events were associated with EEG arousals. In 13 patients with or without clonazepam, the motor events gradually disappeared, and the rest turned to be sporadic. Conclusion: SRFMM is a characteristic parasomnia manifested by tongue biting and accompanying facial mandibular myoclonus, leading to disrupted sleep. Besides adults, infants can also experience SRFMM with spontaneous remission. Most patients respond well to clonazepam, eventually with favorable prognosis.

Sudden unexpected death in epilepsy disclosure causes anxiety in patients with epilepsy: a Chinese questionnaire survey.

Background and objective: Sudden unexpected death in epilepsy (SUDEP) has been regarded as a leading cause of premature death in patients with epilepsy (PWE). Although patients, relatives and caregivers have the right to be informed of SUDEP, neurologists prefer not to release the facts for fear of associated anxiety. In the study, a Chinese questionnaire survey was carried out to elucidate effect of SUDEP disclosure on anxiety in PWE and variables determining the anxiety of patients and provided suggestions for SUDEP disclosure. Methods: A survey study in China was conducted. We recruited 305 PWE from 3 tertiary epilepsy centers who attended outpatient clinic from December 2021 to February 2022. Two hundred and thirty-two PWE completed the screening evaluation, survey and Hamilton anxiety rating scale (HAMA) twice with 171 PWE completing third HAMA at follow-up. HAMA scores at baseline, T1, T2 were compared using analysis of variance and dependent samples t-test. The variables related to anxiety were screened out by univariate analysis and used for multivariate logistic regression. Result: We found 127 (54.7%) among the 232 participants experienced anxiety after SUDEP disclosure. HAMA scores at T1 were significantly higher than at baseline and T2, while there was no statistical difference between baseline and T2. Medical insurance, seizure severity, and whether the PWE supported SUDEP being disclosed to their relatives and caregivers only were associated with the occurrence of anxiety. Conclusion: SUDEP disclosures may cause short-term acute anxiety, but have no long-term effects in PWE. Acute anxiety caused by SUDEP disclosure may be more common in PWE with NCMI and severe seizures. Meanwhile, compared with indirect SUDEP disclosure to their relatives and caregivers, direct SUDEP disclosure to PWE reduces the risk of anxiety. Recommendations are provided to avoid anxiety caused by SUDEP disclosure.

Triggering role of acid sphingomyelinase in endothelial lysosome-membrane fusion and dysfunction in coronary arteries.

The present study determined whether activation of acid sphingomyelinase (ASM) drives membrane proximal lysosomes to fuse to the cell surface, facilitating membrane lipid rafts (LRs) clustering in coronary arterial endothelial cells (CAECs) and leading to endothelial dysfunction. By confocal microscopy, the activators of ASM, phosphatidylinositol (PI), and bis (monoacylglyceryl) phosphate (Bis), and an inducer of ASM, butyrate, were found to increase LRs clustering in bovine CAECs, which was blocked by lysosome fusion inhibitor vacuolin-1. However, arsenic trioxide (Ars), an inducer of de novo synthesis of ceramide, had no such effect. Similarly, vacuolin-1-blockable effects were observed using fluorescence resonance energy transfer detection. Liquid chromatography-electrospray ionization-tandem mass spectrometry analysis demonstrated that all of these treatments, even Ars, increased ceramide production in CAECs. When ASM gene was silenced, all treatments except Ars no longer increased ceramide levels. Furthermore, dynamic fluorescence monitoring in live cells showed that PI and Bis stimulated lysosome-membrane fusion in CAECs. Functionally, PI and Bis impaired endothelium-dependent vasodilation in perfused coronary arteries, which was blocked by vacuolin-1 and a lysosome function inhibitor, bafilomycine. FasL (Fas ligand), a previously confirmed lysosome fusion stimulator as a comparison, also produced a similar effect. It is concluded that ASM activation serves as a triggering mechanism and driving force, leading to fusion of membrane proximal lysosomes into LR clusters on the cell membrane of CAECs, which represents a novel mechanism mediating endothelial dysfunction during death receptor activation or other pathological situation.

Acid sphingomyelinase/ceramide mediates structural remodeling of cerebral artery and small mesenteric artery in simulated weightless rats.

AIMS: Weightlessness exposure conduces to substantial vascular remodeling, mechanisms behind which remain unclear. Acid sphingomyelinase (ASM) catalyzed ceramide (Cer) generation accounts for multiple vascular disorders, so the role of it in adjustment of cerebral artery (CA) and small mesenteric artery (MA) was investigated in simulated weightless rats. MAIN METHODS: Rats were hindlimb unloaded tail suspended (HU) to simulate the effect of weightlessness. Arterial morphology was examined by hematoxylin-eosin staining. Cer abundance was measured by immunohistochemistry. Western blotting was used to detect protein content. Apoptosis was detected by transferase-mediated dUTP nick end labeling. KEY FINDINGS: During 4 weeks of tail suspension, intima-media thickness (IMT) and media cross section area (CSA) were increased gradually in CA but decreased gradually in MA (P < 0.05). Correspondingly, the apoptosis and proliferation of vascular smooth muscle cells were reduced and enhanced respectively in CA (P < 0.05), while promoted and restrained in MA (P < 0.05). As compared to control, both ASM protein expression and Cer content were lowered in CA and elevated in MA of HU rats (P < 0.05). Permeable Cer incubation reversed the change of apoptosis and proliferation in CA of HU rats, while ASM inhibition recapitulated it in control rats. On the contrary, ASM inhibitors restored the alteration of apoptosis and proliferation in MA of HU. SIGNIFICANCE: The results suggest that by controlling the balance between apoptosis and proliferation, ASM/Cer exerts an important role in structural adaptation of CA and MA to simulated weightlessness.