Reduced endoplasmic reticulum stress might alter the course of heart failure via caspase-12 and JNK pathways.

BACKGROUND: Endoplasmic reticulum (ER) stress plays an important role in mediating ischemic heart cell death. The aim of this study was to investigate whether manipulation of a key factor of the ER stress pathway, eukaryotic translation initiation factor 2 subunit α (eIF2α), can change the natural history of heart failure (HF). METHODS: HF was induced using coronary artery ligation in adult rats and a selective eIF2α dephosphorylation inhibitor, salubrinal (Sal), was used. Thirty minutes after ligation, rats were randomly assigned to 3 groups: myocardial infarction (MI) plus placebo injections (dimethyl sulfoxide; n = 12), MI plus Sal injection (Sal; n = 12), and MI (HF; n = 12). Hemodynamic parameters were examined. Hearts were harvested for apoptosis assessment after 8 weeks of Sal treatment by terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labelling and flow cytometric analysis. Hearts were harvested to determine ER chaperones by Western analysis, real-time polymerase chain reaction and immunohistochemical analysis. RESULTS: Cardiac function was significantly improved in Sal-treated rats. Apoptosis was reduced by Sal treatment. Glucose-regulated protein-78 and -94 were increased in HF but normalized by Sal treatment. HF caused a significant increase in eIF2α phosphorylation, which was further increased by Sal treatment, and caspase-12 and phospho-c-JUN NH2-terminal kinase were markedly increased in rats with HF alone but significantly reduced by Sal treatment. CONCLUSIONS: Our results suggest that reduction of ER stress and myocardial apoptosis through inhibition of eIF2α dephosphorylation might alter the natural history of HF, which might provide a new approach for its treatment.

[Analyses of super-response to cardiac resynchronization therapy in patients with congestive heart failure: a multiple center trial].

OBJECTIVE: To evaluate the incidence of super-response and the potential predictors related to super-response after cardiac resynchronization therapy (CRT) in patients with congestive heart failure. METHODS: 190 patients [145 men and 45 women;age: (60.48 ± 11.91) years] underwent CRT between March 2001 and March 2012 were enrolled in this multi-center trial, of which, 54 patients with ischemic cardiomyopathy and 136 patients with non-ischemic cardiomyopathy. These patients were followed up from 6 months to 11 years (mean 58 months) post CRT. RESULTS: Ten patients died within 6 months post CRT, the others were followed up for more than 6 months. At 6-month follow-up, 51 patients were identified as CRT super-responders (28.33%), 75 patients were CRT responders (41.67%) and 29 patients were CRT non-responders (16.11%), and 25 patients were CRT negative responders (13.89%). Super-response occurred more frequently in non-ischemic cardiomyopathy patients, while non-response most commonly occurred in ischemic cardiomyopathy patients (P < 0.05); patients in the negative response group had higher serum creatinine level than other groups (P < 0.05) , and patients in the non-response group and negative response group had higher pulmonary artery pressure than patients in the super-response group (P < 0.05); the average QRS duration was ≥ 160 ms before CRT, and the mean decrease was around 30 ms after CRT in the super-response group while the average QRS duration was 139 ms before CRT, and the mean reduction was around 8 ms after CRT in the negative response group (P < 0.05). LV lead position in the super-response group was usually in the middle and base of the heart, while in the negative response group it was more commonly located in the apex of the heart (P < 0.01) . CONCLUSIONS: LV lead located at the middle and pre-CRT ORS duration ≥ 160 ms are associated with super-response post CRT procedure in this patient cohort.

[Causes of non-response to cardiac resynchronization therapy in heart failure patients with permanent atrial fibrillation].

OBJECTIVE: To evaluate the long-term effects and analyze causes of non-response to cardiac resynchronization therapy (CRT) in heart failure (HF) patients with permanent atrial fibrillation (AF). METHODS: Thirty-three patients with HF and AF [29 men, mean age (61 ± 10) years, NYHA class III or IV, left ventricular ejection fraction (LVEF) ≤ 35%, QRS ≥ 120 ms in 31 cases] underwent bi-ventricular pacing (n = 26) or bi-ventricular pacing and atrioventricular node ablation (AVN-ablation, n = 7) were included in this study. Non-response was defined: the increase of left ventricular ejection fraction (LVEF) was less than 15%. Patients were followed-up for 4 years. RESULTS: Six patients died during follow up. Non-responder to CRT was observed in 6 out of 27 survived patients (22.22%). Six out of 7 patients underwent AVN-ablation were in responder group and 1 in non-responder group. Comparing with responder group, the baseline LVEF was significantly higher (37% vs. 32%, P = 0.003), and the history of HF was significantly longer (6.3 years vs. 4.1 years, P = 0.039), pulmonary artery pressure was significantly higher (53 vs. 32 mm Hg, P = 0.027), bi-ventricular pacing percentage (BIVP%) was significantly lower (75.86% vs. 91.73%, P = 0.007) in non-responder group. CONCLUSIONS: Higher LVEF, longer HF history, higher pulmonary artery pressure and lower BIVP% are factors linked with non-responses to CRT in this patient cohort. CRT plus AVN-ablation is associated with high response rate to CRT in this patient cohort.

[The mechanistic rote of KCNH2 gene L413P and L559H mutations in long QT syndrome].

OBJECTIVE: To investigate the molecular pathogenesis for two novel mutations L413P and L559H of KCNH2 found in Chinese patients with long QT syndrome. METHODS: L413P and L559H mutant constructs were generated by site-directed mutagenesis using human wild-type (WT) pcDNA3-HERG cDNA as a template. WT and mutant constructs were transiently transfected into human embryonic kidney 293 cells using lipofectamine method. After transfection, the recording of HERG current was performed using patch clamp technique. The expression and cellular localization of HERG protein were studied with Western blot and immunofluorescence methods. RESULTS: Electrophysiological recordings showed that L413P and L559H mutations did not express HERG current. Western blot analysis revealed that only 135 000 immature HERG protein was expressed in L413P and L559H-transfected cells, whereas both mature and immature forms of HERG protein were observed in WT-transfected cells. Immunofluorescence study showed that L413P and L559H mutant proteins were predominantly localized around the nucleus, suggesting that the mutant channels are retained in the endoplasmic reticulum. When L413P or L559H was co-transfected with equal amount of WT plasmids, both 135 000 and 155 000 forms of HERG protein were observed, and the HERG current was not significantly changed as compared with that of WT transfection alone. Low temperature and E-4031could not rescue these two mutant channels. CONCLUSIONS: The L413P and L559H mutations resulted in protein trafficking defects with failure of mutant proteins to reach the plasma membrane. However, both biochemical and electrophysiological results showed that the mutations did not have a dominant-negative effect on WT, indicating that the mechanism of the L413P and L559H mutations might be haploinsufficiency.

Expression and clinical significance of vascular endothelial growth factor, cyclooxygenase-2, and Bcl-2 in borderline ovarian tumors.

OBJECTIVE: The objectives were to study the expression of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (Cox-2), and Bcl-2 in borderline ovarian tumors (BOTs) and the relationship within them, and to investigate the correlation between expression of VEGF, Cox-2, and Bcl-2, and the clinicopathologic features of BOTs. METHODS: An immunohistochemical technique was used to investigate the expression of VEGF ,Cox-2, and Bcl-2 in 69 borderline, 18 benign, and 27 malignant human ovarian tumor tissues. RESULTS: Expression rate of VEGF protein (59.4%) in BOTs was higher than in benign tumors (27.8%) and was lower than in ovarian carcinomas (92.6%), and there was a significant difference between BOTs and benign ovarian tumors (p < 0.05), and carcinoma (p < 0.01). Significant correlation was observed between the positive expression rate for VEGF and clinical stage of BOTs (p < 0.05). The statistical analysis did not show a close correlation between the expression of VEGF and tissue type, and peritoneal implants in BOTs (p > 0.05). The expression rate of Cox-2 was significantly higher in ovarian carcinomas (81.5%) than in BOTs (57.9%) and in benign ovarian tumors (38.9%) (p < 0.05). Significant correlation was observed between the positive expression rate for Cox-2 and the clinical stage of BOTs (p < 0.05). The statistical analysis showed no close correlation between the expression of Cox-2 and tissue type, and peritoneal implants in BOTs (p > 0.05). There was a significant difference between the expression of Bcl-2 in ovarian carcinomas and BOTs than that in benign ovarian tumors (p < 0.05). The positive expression rate of Bcl-2 was not related to clinical stages and peritoneal implants (p > 0.05). Statistical analysis showed a positive correlation between the expression of Cox-2 and VEGF, and Bcl-2 in BOTs. CONCLUSIONS: Overexpression of VEGF, Cox-2, and Bcl-2 in BOTs may play an important role in the oncogenesis and progression of BOTs. It is feasible to detect VEGF, Cox-2, and Bcl-2 in the diagnosis and to predict the prognosis of BOTs.

[Effect of simulated ischemia on activity and heterogeneity of Na+ channel in rabbit ventricular epicardial, midmyocardial and endocardial myocytes].

OBJECTIVE: To study the ionic mechanism of reentrant arrhythmia. METHODS: Single myocytes were enzymatically isolated from the epicardium, midmyocardium and endocardium of the left ventricle free wall of rabbit, followed by whole-cell patch-clamp recording of the Na(+) current (I(Na)) of the 3 cellular subtypes (superfused with normal and then simulated ischemia solution). The currents in the 3 cellular subtypes before and after simulated ischemia lasting for 10, 20, and 30 min, respectively, were compared. RESULTS: No changes was recorded in the configuration of the I-V curves and voltage dependence of I(Na) after simulated ischemia, and the peak I(Na) densities (- 20 mV) were significantly reduced in the 3 cellular subtypes compared with those recorded in normal condition. At the same time, the differences in I(Na) peak current densities in the 3 cellular subtypes underwent variations after simulated ischemia. Simulated ischemia resulted in obvious shift of I(Na) steady-state inactivation curves in the hyperpolarizing direction in the 3 cellular subtypes and inactivation was accelerated, and the differences in the half maximal inactivation voltages (V0.5) between the 3 cellular subtypes were also altered after simulated ischemia. After simulated ischemia, I(Na) recovery from inactivation in the epicardium, endocardium and midmyocardium was all slowed down in comparison with that in normal condition, but without statistical significance. Differences between the recovery curves of three cellular subtypes were noted after ischemia for 30 min. CONCLUSION: Ischemia can affect the activity of Na(+) channel, disrupting the balance of ion channel currents and the heterogeneity of I(Na) among the 3 cellular subtypes, which is responsible for the onset of arrhythmia and partially explains different pharmacological reactions of the 3 cellular subtypes under normal and ischemic conditions.

[Expression of vascular endothelial growth factor and microvessel density in ovarian tumor].

BACKGROUND & OBJECTIVE: Angiogenesis is a critical step in growth, invasion, and metastasis of solid tumors, and determination of microvessel of density (MVD) could be used to evaluate angiogenesis. Vascular endothelial growth factor (VEGF) is an important angiogenic factor, which involves in tumor growth. This study was designed to investigate the relationship between the expression of VEGF and MVD in borderline ovarian tumor. METHODS: SP immunohistochemistry and in situ hybridization were used to investigate the expression of VEGF and VEGF mRNA in 69 samples of borderline ovarian tumor (BOT), 18 samples of benign tumor and 27 samples of ovarian carcinoma (OC). MVD was counted by endothelial cells immunostained with anti-factor VIII monoclonal antibody. RESULTS: The expression levels of VEGF protein and VEGF mRNA were middle in borderline ovarian tumors between in benign tumors and in carcinoma, with significant differences (P< 0.05). The expression of VEGF and VEGF mRNA were closely associated with clinic stage and MVD(P< 0.05), but were not associated with tissue type and peritoneal implants(P > 0.05). CONCLUSION: VEGF is associated with the development, invasion, and metastasis of ovarian tumor. VEGF and MVD were predictors for the prognosis of borderline ovarian tumor.