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1.

1 Introduction

New onset of ventricular fibrillation (VF) in asymptomatic patients with Brugada‐type ECG is not frequent, but it cannot be negligible. Risk markers for predicting VF are usually based on results of analysis in symptomatic patients, and they have not been determined for asymptomatic patients. We analyzed ECG markers in patients with Brugada syndrome to differentiate the risk factors for VF in both symptomatic and asymptomatic patients.

2 Methods

The subjects were 471 patients with Brugada syndrome and we divided the subjects into two groups: Asymptomatic group (n = 326) and Symptomatic group (syncope: n = 122, VF: n = 23). We analyzed the following ECG markers: RR, PQ, QRS, QT and Tpeak‐Tend (Tpe) intervals, ST level, atrial fibrillation (AF), atrioventricular block, spontaneous type 1 ECG, early repolarization (ER) and fragmented QRS (fQRS).

3 Results

During follow‐up (91 ± 64 months), 41 patients experienced VF (Asymptomatic: n = 10, Symptomatic: n = 31). Univariable analysis showed that spontaneous type 1 ECG, Tpe interval (≥95 milliseconds), high ST level (≥0.52 mV) and fQRS were common predictors for VF in both the Asymptomatic and Symptomatic groups. In addition to the common risk factors, wide QRS (≥107 milliseconds), long QT interval (≥420 milliseconds), ER and AF were predictors for VF in Symptomatic group. Multivariable analysis of the Symptomatic group showed fQRS, Tpe and ER were independent predictors of prognosis.

4 Conclusions

fQRS and Tpe interval are common risk factors for VF in both asymptomatic and symptomatic patients, whereas ER is a predictor for recurrent VF.  相似文献   

2.
BackgroundAn early repolarization (ER) pattern is a risk factor for ventricular fibrillation (VF) in patients with vasospastic angina (VSA) caused by a coronary artery spasm. However, its detailed characteristics and prognostic value for VF remain unclear. Thus, we investigated the relationship between ER and VF in patients with VSA.HypothesisThe ER pattern is associated with VF in patients with VSA.MethodsIn this systematic review and meta‐analysis, we searched PubMed, Embase, Cochrane Library, and Web of Science databases for eligible studies published between January 2011 and December 2020; 8 studies with 1761 patients were included in the final analysis.ResultsThe ER pattern significantly predicted adverse cardiovascular events (ACEs) and VF (odds ratio [OR] = 5.13, 95% confidence interval [95% CI]: 3.16–8.35, p < .00001 and OR = 5.20, 95% CI: 3.05–8.87, p < .00001). The presence of ER in the inferior leads increased the VF risk (OR = 7.80, 95% CI: 4.04–15.05, p < .00001), regardless of the J‐point morphology or type of ST‐segment elevation in the ER pattern. A horizontal/descending ST‐segment elevation was significantly associated with VF in patients with or without an ER pattern during a coronary spasm (OR = 2.28, 95% CI: 1.07–4.88, p = .03). However, obstructive coronary artery disease was unrelated to the ER pattern (OR = 0.82, 95% CI: 0.27–2.53, p = .73).ConclusionsAn ER pattern is significantly associated with an increased risk of ACE in patients with VSA. An inferior ER pattern with horizontal/descending ST‐segment elevation confers the highest risk for VF during VSA onset. Nevertheless, the ER pattern is not associated with obstructive coronary artery disease.  相似文献   

3.
《Heart rhythm》2023,20(6):844-852
BackgroundVentricular fibrillation (VF) can be initiated by ventricular premature depolarizations (VPDs) in the absence of obvious structural abnormalities.ObjectiveThe purpose of this study was to determine the prevalence of 12-lead electrocardiographic (ECG) sinus rhythm reduced QRS amplitude, QRS fractionation (QRSf), and early repolarization (ER) pattern, and the outcome of catheter ablation and VPD anatomic distribution in patients with VPDs initiating VF.MethodsWe compared a cohort with no apparent structural heart disease and VPDs initiating VF (group 1; n = 42) to a reference cohort (group 2; n = 61) of patients with no structural heart disease and symptomatic unifocal VPDs.ResultsA reduced QRS amplitude (<0.55 mV) in aVF (59% vs 10%; P <.001), QRSf in ≥2 contiguous leads (50% vs 16%; P <.001), and ER pattern (21.4% vs 1.6%; P = .01) were more common in group 1 than in group 2. At least 1 abnormal ECG finding was present in 34 group 1 patients (81%) vs 17 group 2 patients (28%) (P <.001). VPD origin included right ventricular and left ventricular distal Purkinje system and moderator band/papillary muscles in 83% of group 1 patients vs 18% of group 2 patients (P <.001). VF was eliminated with a single ablation procedure in 77% of group 1 patients with at least 2 years of follow-up.ConclusionA reduced QRS amplitude (<0.55 mV) in aVF, QRSf in ≥2 contiguous leads, and/or an ER pattern are frequently observed in patients with VPDs initiating VF. VPDs initiating VF typically originate from the distal Purkinje system and papillary muscles and can be successfully eliminated with catheter ablation.  相似文献   

4.
Early repolarization (ER) has been accepted as a benign ECG variant for decades. Two seminal studies challenged this notion and have demonstrated that ER pattern is associated with an increased risk of arrhythmic and cardiac mortality in patients with idiopathic ventricular fibrillation (IVF) and in the general population. Recent clinical studies demonstrate its varying impact as an arrhythmogenic substrate on different diseases. For example, in ER syndrome, a primary electrical disease, ER appears as a major arrhythmogenic substrate for development of VF whereas in patients with coronary artery disease, an ER pattern may exist as a silent substrate, increasing the risk of VF during episodes of cardiac ischaemia. Due to the high prevalence of an ER pattern in the general population and a low VF event rate, it remains challenging to differentiate a malignant ER pattern from a benign form. Recent research suggests that a J-wave amplitude of more than 0.1 mV combined with a descending/horizontal ST segment may constitute a malignant ER pattern. Further studies are however necessary to evaluate its prognostic value for cardiac and arrhythmic death in the general population as well as in cases with a malignant ER pattern. While genetic testing has revealed putative causal DNA variants in sporadic cases, the lack of co-segregation with the disease in affected families suggests that ER syndrome is not monogenic but is likely a complex disorder influenced by multiple genetic as well as environmental factors.  相似文献   

5.
6.
Early repolarization (ER) pattern has been recognized for several decades and was interpreted as a variant of the normal electrocardiogram (ECG) as it was frequently observed in young healthy subjects or athletes. It is characterized by a J point elevation and ST-segment elevation inscribed as a QRS slurring or a notch of the S wave in the inferior leads or/and the lateral leads. The ER pattern has been the subject of increased interest since the report of its higher prevalence in subjects resuscitated from cardiac arrest related to idiopathic ventricular fibrillation (VF). Furthermore, population-based studies showed in healthy young adults that ER pattern was associated with an increased cardiovascular mortality and total mortality. A relationship between ER pattern and malignant arrhythmias is also supported by the experimental work of Antzelevitch et al. which provided the cellular and ionic basis for the J point elevation and its arrhythmogenic potential. The ER pattern may coexist with a number of cardiac or extracardiac conditions such as hypothermia. But this review will focus attention on the “isolated ER pattern” in healthy individuals. Antzelevitch and Yan proposed because of a number of similarities between the “ER syndrome” and the Brugada syndrome to group both syndromes under the heading of “J wave syndromes”. The management of ER syndrome (associated with idiopathic VF) is clearly the insertion of an implantable cardioverter defibrillator (ICD). The ER pattern associated with symptoms such as syncope or a familial history of sudden cardiac death requires a complete work-up. Caution should be raised not to generate anxiety in the subject with asymptomatic “isolated ER pattern” as the odds of developing malignant ventricular arrhythmias or to suffer sudden death in this case are extremely low.  相似文献   

7.
It is still unclear whether there are clinically exploitable differences in the biology and behaviour of early versus late relapses in diffuse large B‐cell lymphoma (DLBCL). The present study aimed to analyse a large population‐based DLBCL cohort in order to identify (i) the frequency of late relapses (LR), (ii) parameters influencing the risk of LR, and (iii) the impact of introducing rituximab on the occurrence of LR. The data of 7247 DLBCL patients was obtained from the Danish Lymphoma Group Registry. Patients with LR had a lower International Prognostic Index and better performance score than early relapse (ER) patients. The use of radiotherapy lowered only the rate of ER while the use of rituximab yielded a lower occurrence of both ER and LR (P < 0·0001 and P < 0·0001, respectively), possibly suggesting a longer‐lasting biological effect. Additionally, we found a female overrepresentation among LR patients that had received a rituximab‐containing first line treatment. It was found that patients with LR had a significantly better 5‐year overall survival compared to ER patients. In conclusion, LR was more frequently associated with low‐risk features than ER. Furthermore, we found that the use of modern immunochemotherapy regimens in DLBCL lowers the risk of both ER and LR.  相似文献   

8.
Peginterferon/ribavirin has been the standard‐of‐care for chronic hepatitis C virus (HCV) infections: 48 weeks for genotype 1 or 4 (HCV‐1/4) and 24 weeks for HCV‐2/3. Response‐guided therapy recommended shorter 24‐ and 16‐week regimens for HCV‐1 with lower baseline viral loads (< 400 000–800 000 IU/mL) and rapid virological response (RVR, undetectable HCV RNA at week 4) and HCV‐2/3 with RVR, respectively; and extending to 72 and 48 weeks for HCV‐1 slower responders and HCV‐2 non‐RVR patients, respectively, to improve the efficacy. The progress of directly acting antivirals (DAA), moving from interferon‐containing regimens in 2011 to interferon‐free regimens in 2013, has greatly improved the treatment success. Interferon‐containing regimens include boceprevir or telaprevir or simeprevir or daclatasvir plus peginterferon/ribavirin, 24–48 weeks, for HCV‐1 or 4. However, adding these DAA has no benefit for HCV‐1 with lower baseline viral loads/RVR. Instead, 12‐week sofosbuvir plus peginterferon/ribavirin attained sustained virological response rates of > 90% for HCV‐1/3–6. Interferon‐free regimens include two main categories: NS5B nucleotide inhibitor (sofosbuvir)‐based regimens and NS3/4A inhibitor/NS5A inhibitor‐based regimens (daclatasvir/asunaprevir, paritaprevir/r/ombitasvir/dasabuvir and grazoprevir/elbasvir). About 8–24 weeks interferon‐free regimens could achieve sustained virological response rates of 82–99% for corresponding HCV genotypes. Although the newly DAA interferon‐free regimens have high efficacy and safety, the huge budget impact increases the treatment barriers. The current recommendation should, therefore, base on the availability, indication, and cost‐effectiveness in the transition era of DAA. Based on the concept of “resource‐guided therapy,” peginterferon/ribavirin might be applied for easy‐to‐treat interferon‐eligible patients in resource‐constrained areas. Prioritizing patients for interferon‐free regimens according to “time‐degenerative factors” (age and fibrosis) is justified before the regimens becoming available and affordable.  相似文献   

9.
J‐Wave Disaapearance After an Episode of Ventricular Fibrillation . Early repolarization (ER) abnormalities in the inferior‐lateral leads are a matter of intense scientific debate because of their demonstrated association with Brugada syndrome (BS) and idiopathic ventricular fibrillation (VF). To add fuel to the fire, we present a case in which ER abnormalities are associated with BS but in which, more importantly, they were shown to be transient and strictly correlated with an episode of VF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1413‐1415, December 2010)  相似文献   

10.
Background and Aim: Surgery is not recommended in asymptomatic patients with aortic stenosis (AS). However, prognosis of these patients is worse than retained. We built a simple score (named by the acronym “CAIMAN”) for stratifying asymptomatic patients with AS according to the different risk for cardiovascular events. Material and Methods: Data from 141 patients with moderate‐to‐severe AS followed up for 36 months were analyzed. The end point “outcome” was defined as death of all causes or aortic valve replacement imposed by symptoms or hospital admission for myocardial infarction and/or heart failure. The score was validated in 143 patients prospectively recruited in 2 different centers. Results: The 40 events occurred in the original cohort were associated with higher aortic transvalvular peak jet velocity, calcium score, and observed/predicted left ventricular (LV) mass ratio. Based on the hazard ratios of Cox analysis, the score was calculated as follows: calcium score 1–3 = 1 point, 4 = 6 points; transvalvular peak jet velocity ≤3.6 m/sec = 1 point, 3.6 m/sec = 3 points, observed/predicted LV mass ratio ≤110% = 1 point, >110% = 3 points. After a mean period of 28 ± 18 months, event‐free survival was 18%, 42%, 91%, and 96% in the 4 quartiles of echo score. The accuracy of the score in predicting events was 84% and 77% (P = 0.09) in the original and validation cohort, respectively. Conclusions: The CAIMAN‐ECHO score is a simple and feasible tool useful for an accurate prognostic stratification of patients with asymptomatic moderate‐to‐severe AS.  相似文献   

11.
Magnetic resonance imaging (MRI) and ultrasonography (US) are increasingly used in haemophilia A (HA) to detect early joint changes. A total of 40 clinically asymptomatic joints, never involved by bleeding events [“healthy joints” (HJ)], were evaluated by MRI and, in parallel, by US in 20 young subjects with severe HA (22.45 ± 2.72 years old; no history of arthritides, of viral infections or of inhibitors against factor VIII). The same joints were evaluated in 20 matched non‐haemophilic (no‐HA) subjects (mean age 23.90 ± 2.31 years, = 0.078 vs. HA subjects). US images were obtained with specific probe positions according to validated procedures. A validated US score and progressive (P‐MRI) and additive (A‐MRI) MRI scores were employed for data collection and analysis. The US score was higher in HA than in no‐HA subjects (3.40 ± 1.72 vs. 0.80 ± 1.10, < 0.001). Taking into account only moderate/severe alterations, joint effusion was found in 55% of HA and in 5% of no‐HA joints (< 0.001); synovial hypertrophy was found in 20% of HA and in none of the no‐HA joints; cartilage erosion was found in 30% of HA and in none of no‐HA joints. MRI examinations confirmed these findings and the US score correlated with the A‐MRI (r = 0.732, < 0.001) and with the P‐MRI (r = 0.598, < 0.001) scores. MRI and US data significantly correlated as to effusion (r = 0.819, = 0.002), synovial hypertrophy (r = 0.633, = 0.036) and cartilage erosion (r = 0.734, = 0.010). Despite inherent limitations, joint US examination identified subclinical abnormalities of HJ in young subjects with severe HA.  相似文献   

12.

Context

Although endogenous oestradiol, generally considered as the female hormone, has been little investigated in men, it could play a role in men's health, mortality in particular. The influence of oestrogen receptors (ER) genetic polymorphisms on this relationship has never been studied.

Design and Participants

The Three‐City cohort study included (1999‐2001) 3650 men ≥65 years who were followed for mortality over 12 years. At baseline, total oestradiol (tE2) was measured and ER genotyped in a random subsample of 472 men without hormonal treatment. Free oestradiol (fE2) was estimated using Vermeulen and Södergard algorithms.

Main Outcome

Mortality data were obtained from death certificates. We used inverse probability weighted Cox models to examine the association of oestradiol with all‐cause and cause‐specific mortality and its interaction with ER genetic polymorphisms.

Results

A total of 183 men died over the follow‐up (cardiovascular disease (CVD), n = 44; cancer, n = 57; other causes, n = 82). After adjustment, there was a quadratic relationship of all‐cause mortality with tE2 and fE2 (P‐quadratic = 0.04 and 0.05, respectively), with higher mortality for the top and bottom tertiles compared to the middle one. These associations were stronger for CVD mortality (P‐quadratic = 0.01 and 0.02 for tE2 and fE2, respectively) and disappeared for cancer mortality. There was no evidence of an interaction of oestradiol with any ER polymorphisms on all‐cause mortality.

Conclusion

In elderly men, we showed a nonlinear association of tE2 and fE2 with all‐cause mortality. These quadratic relationships were stronger for CVD mortality and did not exist for cancer mortality. ER genetic polymorphisms did not modify this association.  相似文献   

13.
The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed. 19 patients that fulfilled the investigation criteria were followed up for 71 ± 49 months (34–190 months). Prior to the event (syncope/VF), the patients were partaking different activities in the following decreasing order; drinking alcoholic beverage, having meal, and getting up from sleep, exercise. 3 patients reported mental/physical stress prior to the event and 2 patients developed VF several days after starting oral steroid for treatment of bronchial asthma. In the ER, elevated J-wave amplitude (0.27 ± 0.15 mV) was found with 58 % of the patients having hypokalemia. After electrolyte correction and cessation of steroids, the following day plasma K+ (4.2 ± 0.3 mEq/L, P < 0.001) was significantly increased and J-wave amplitude (0.13 ± 0.1 mV, P < 0.001) was remarkably reduced. Three patients were kept on oral spironolactone/potassium supplements. During follow-up for 71 ± 49 (34–190) months, among 4 patients with VF recurrence, one patient developed VF after taking oral steroid. In ERS and BrS, hypokalemia and corticosteroid therapy add substantial pro-arrhythmic effects, but potentially treatable. Stopping steroid therapy and avoiding hypokalemia had excellent long-term outcome.  相似文献   

14.
Cardiac myxomas are frequently located in the left or right atria, with multiple locations being rare. We report a 59‐year‐old healthy female with 5 months of cough and exertional dyspnea. A transthoracic echocardiography (TTE) exhibits a 9 × 5 cm nonpedunculated tumor arising from the interatrial septum (IAS) and inhabiting both atria, but was unable to depict the relation with the IAS. Transesophageal echocardiography exposes a single tumor crossing the IAS through an ostium secundum atrial septal defect (ASD) causing right heart functional impairment. Uneventful cardiac surgery allowed complete resection of the lesion and ASD closure. Pathology reported a myxoma.  相似文献   

15.
The role of the endogenous interferon (IFN) system has been well characterized during IFN‐based therapy for chronic hepatitis C virus (HCV) infection; less is known for direct‐acting antivirals (DAAs). In this phase 3b open‐label study, we assessed changes in IFN‐stimulated genes (ISGs) in non‐cirrhotic treatment‐naïve or pegIFN/RBV‐experienced HCV‐GT1a‐infected patients receiving paritaprevir/ritonavir/ombitasvir + dasabuvir + ribavirin (PrOD + R) for 12 weeks. ISG expression was quantified from peripheral blood mononuclear cells at baseline, treatment weeks (TW)2, TW4, TW8, end of treatment (EOT) and at post‐treatment week 12. Paired sera were used to assess IFN‐α/IFN‐related chemokines/cytokines. Twenty‐five patients were enrolled. Overall sustained virologic response (SVR)12 was 92% (no virologic failure [VF]) and 100% for those completing the study protocol. Two patients were excluded from the ISG analysis due to lack of post‐treatment samples. The majority of ISGs were downregulated at TW2‐TW4 (nadir TW4); however, a relative increase was observed at TW8‐EOT, although levels were lower than baseline. This downregulation was accompanied by increases in IFN‐α/IFN‐related chemokines, a finding not observed with TH1/2‐related cytokines. Following SVR, ISG expression returned to TW2 levels. In conclusion, PrOD + R for 12 weeks was well‐tolerated with no VF. Our data demonstrate dynamic alterations in innate immune profiles during highly potent IFN‐free DAA therapy. The downregulation of ISG post‐therapy suggests reversal of the “exhausted” ISG phenotype following SVR, and the rise in ISGs and IFN‐α/IFN‐responsive chemokines late during therapy suggests resetting of IFN responsiveness that may be relevant in determining duration of or immunological sequelae from DAA therapy, including HBV reactivation.  相似文献   

16.
Left ventricular hypertrophy (LVH) with intraventricular septum thickness (IVST) between 1.2 and 1.5 cm in athletes represents a “gray zone” between physiologic adaptation and mild hypertrophic cardiomyopathy (HCM). Various echo and laboratory parameters have been reported till now in the literature to discriminate the “gray zone” entities. Aim of this study was to assess the efficacy of these “classic” parameters in differentiating physiologic LVH in athletes from mild HCM in a highly selected population. Nine highly trained athletes with IVST (1.28 ± 0.07 cm), 9 patients with mild HCM (1.38 ± 0.11 cm), and 26 athletes without LVH (1.06 ± 0.09 cm; P < 0.0005) underwent echocardiographic study, cardiopulmonary treadmill exercise stress test, and brain natriuretic peptide (BNP) measurement before and after exercise. Among all parameters tested, 7 were found to significantly differ between “gray zone” groups. After bootstrapping analysis, it was found that athletes with left ventricular end‐diastolic diameter <4.74 cm, mitral deceleration time >200 ms, isovolumic relaxation time >94 ms, tricuspid E/A < 1.63, septum Em < 9.5 cm/sec, relative wall thickness >0.445, and a BNP value at rest >9.84 pg/mL had a greater possibility for having underlying cardiomyopathy. A 10‐point score based on these parameters showed accuracy (area under the curve = 0.958 [95%CI: 0.738–1.0; P = 0.00005, standard error = 0.0342]) for revealing HCM in a gray zone athletic population. Differentiation of adaptive LVH versus HCM in a gray zone population could be facilitated by recognition of certain features referring to LV dimensions, diastolic function, and BNP.  相似文献   

17.
Melatonin plays an important role in regulating circadian rhythms. It also acts as a potent antioxidant and regulates glucose and lipid metabolism, although the exact action mechanism is not clear. The α2‐HS‐glycoprotein gene (AHSG) and its protein, fetuin‐A (FETUA), are one of the hepatokines and are known to be associated with insulin resistance and type 2 diabetes. The aim of this study was to determine whether melatonin improves hepatic insulin resistance and hepatic steatosis in a FETUA‐dependent manner. In HepG2 cells treated with 300 μmol/L of palmitic acid, phosphorylated AKT expression decreased, and FETUA expression increased, but this effect was inhibited by treatment with 10 μmol/L of melatonin. However, melatonin did not improve insulin resistance in FETUA‐overexpressing cells, indicating that improvement in insulin resistance by melatonin was dependent on downregulation of FETUA. Moreover, melatonin decreased palmitic acid‐induced ER stress markers, CHOP, Bip, ATF‐6, XBP‐1, ATF‐4, and PERK. In addition, in the high‐fat diet (HFD) mice, oral treatment with 100 mg/kg/day melatonin for 10 weeks reduced body weight gain to one‐third of that of the HFD group and hepatic steatosis. Insulin sensitivity and glucose intolerance improved with the upregulation of muscle p‐AKT protein expression. FETUA expression and ER stress markers in the liver and serum of HFD mice were decreased by melatonin treatment. In conclusion, melatonin can improve hepatic insulin resistance and hepatic steatosis through reduction in ER stress and the resultant AHSG expression.  相似文献   

18.
An early repolarization variant (ERV) in inferolateral leads has recently been associated with vulnerability to ventricular fibrillation. These studies have been conducted in the occidental countries. The prevalence of ERV in the population of the Maghreb is unknown. The aim of this study was to evaluate the prevalence and risk factors of ERV in a young population from Algeria.MethodsWe assessed the prevalence of ERV within a population of 441 healthy subjects (mean age 25 years) using 12-lead electrocardiography. ERV was stratified by three independent cardiologists according to the J-point elevation (≥ 0.1 mV) in the inferior, apicolateral or both leads with QRS slurring or notching.ResultsThe inferolateral ERV pattern was present in 55 subjects (12.4%). A malign ERV (> 2 mm) was present in 5 subjects (9% of ER) and ER in inferior and lateral leads in 40% of ER. An ERV pattern was more frequently associated with young age, male, bradycardia and T wave in V1 lead.ConclusionAn ERV is a common finding in a healthy Algerian young population. This prevalence seems to be more important than other studies due to young age and not to a racial difference. Our population were more at risk that other studies, and we found more T waves in V1 lead in this people, due to an ethnic particularities or a phenotypic association with the Brugada syndrome.  相似文献   

19.
Endoplasmic reticulum (ER) stress is emerging as a factor for the pathogenesis of granular corneal dystrophy type 2 (GCD2). This study was designed to investigate the molecular mechanisms underlying the protective effects of melatonin on ER stress in GCD2. Our results showed that GCD2 corneal fibroblasts were more susceptible to ER stress‐induced death than were wild‐type cells. Melatonin significantly inhibited GCD2 corneal cell death, caspase‐3 activation, and poly (ADP‐ribose) polymerase 1 cleavage caused by the ER stress inducer, tunicamycin. Under ER stress, melatonin significantly suppressed the induction of immunoglobulin heavy‐chain‐binding protein (BiP) and activation of inositol‐requiring enzyme 1α (IRE1α), and their downstream target, alternative splicing of X‐box binding protein 1(XBP1). Notably, the reduction in BiP and IRE1α by melatonin was suppressed by the ubiquitin‐proteasome inhibitor, MG132, but not by the autophagy inhibitor, bafilomycin A1, indicating involvement of the ER‐associated protein degradation (ERAD) system. Melatonin treatment reduced the levels of transforming growth factor‐β‐induced protein (TGFBIp) significantly, and this reduction was suppressed by MG132. We also found reduced mRNA expression of the ERAD system components HRD1 and SEL1L, and a reduced level of SEL1L protein in GCD2 cells. Interestingly, melatonin treatments enhanced SEL1L levels and suppressed the inhibition of SEL1L N‐glycosylation caused by tunicamycin. In conclusion, this study provides new insights into the mechanisms by which melatonin confers its protective actions during ER stress. The results also indicate that melatonin might have potential as a therapeutic agent for ER stress‐related diseases including GCD2.  相似文献   

20.
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