BANP Participates in the Chronic Intermittent Hypoxia-Induced Senescence of Vascular Endothelial Cells by Promoting P53 Phosphorylation and Nuclear Retention.

INTRODUCTION: The objective of this study was to examine the potential induction of senescence in vascular endothelial cells (VECs) by chronic intermittent hypoxia (CIH), a defining characteristic of obstructive sleep apnea (OSA). This investigation seeks to elucidate the underlying mechanisms that contribute to the development of cardiovascular diseases in patients with OSA, with a particular focus on CIH-induced vascular aging. METHODS: The BioSpherix-OxyCycler system was used to establish models of CIH in both rats and human umbilical vein endothelial cells (HUVECs). To assess VECs' senescence, various methods were employed including EdU incorporation assay, cell cycle analysis, senescence-associated ß-galactosidase (SA-ß-gal) staining, and senescence protein testing. Vascular aging was evaluated through measurements of carotid-femoral pulse wave velocity, intima-media thickness, and Ki67 immunohistochemical staining. In order to identify the molecular mechanisms associated with CIH-induced senescence in VECs, a bioinformatics study was conducted utilizing the Gene Expression Omnibus database. RESULTS: Under conditions of CIH, HUVECs exhibited inhibited proliferation, arrested cell cycle, increased activity of SA-ß-gal, and elevated expression levels of p53 and p21 compared to HUVECs under normoxic conditions. Similarly, rats exposed to CIH displayed increased carotid-femoral pulse wave velocity, intima-media thickness, vascular permeability, and SA-ß-gal activity in VECs, along with decreased expression of arterial Ki67. BTG3-associated protein (BANP) was found to be highly expressed in CIH-induced VECs. Furthermore, the overexpression of BANP resulted in the senescence of VECs, along with elevated levels of p53 phosphorylation and nuclear localization. CONCLUSIONS: These findings demonstrate that CIH can induce VECs senescence and contribute to vascular aging. Additionally, BANP can induce VECs senescence by promoting p53 phosphorylation and nuclear retention. These discoveries offer novel insights into the increased cardiovascular risk associated with OSA, thereby presenting new possibilities for therapeutic intervention.

Effects of obstructive sleep apnea on myocardial injury and dysfunction: a review focused on the molecular mechanisms of intermittent hypoxia.

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH) and is strongly associated with adverse cardiovascular outcomes. Myocardial injury and dysfunction have been commonly observed in clinical practice, particularly in patients with severe OSA. However, the underlying mechanisms remain obscure. In this review, we summarized the molecular mechanisms by which IH impact on myocardial injury and dysfunction. In brief, IH-induced cardiomyocyte death proceeds through the regulation of multiple biological processes, including differentially expressed transcription factors, alternative epigenetic programs, and altered post-translational modification. Besides cell death, various cardiomyocyte injuries, such as endoplasmic reticulum stress, occurs with IH. In addition to the direct effects on cardiomyocytes, IH has been found to deteriorate myocardial blood and energy supply by affecting the microvascular structure and disrupting glucose and lipid metabolism. For better diagnosis and treatment of OSA, further studies on the molecular mechanisms of IH-induced myocardial injury and dysfunction are essential.

Validation of evaluating left ventricular diastolic function with estimated left atrial volume from anteroposterior diameter.

BACKGROUND: Left atrial (LA) volume (LAV) is one of the recommended key variables for evaluating left ventricular (LV) diastolic function. However, only LA anteroposterior diameter (LAAP) is available in numerous large-scale existing databases. Therefore, this study aimed to validate whether LV diastolic function could be evaluated with estimated LAV from LAAP. METHODS: A total of 552 inpatients with sinus rhythm were consecutively enrolled. LAV was measured by biplane Simpson's disk summation method. LV diastolic function was evaluated according to the 2016 proposed recommendations. Best-fitting regression models of LAAP index (LAAPI)-LAV index (LAVI) were developed and equations with the highest F-value were chosen in the first 276 subjects (derivation set), and concordance for evaluating LV diastolic function between using estimated and observed LAVI was verified in the remaining 276 subjects (validation set). RESULTS: In the derivation set, the linear model has the highest F-value in all subjects and in the subjects with normal or depressed LV ejection fraction. In the validation set, using the linear equation (LAVI = 2.05 × LAAPI - 13.86), the higher area under curve and narrower range of difference were shown between estimated LAVI and observed LAVI, respectively. Further, concordance for diagnosis (overall proportion of agreement, 88.4%; κ = 0.79) and grading (overall proportion of agreement, 84.8%; κ = 0.74) of LV diastolic dysfunction was substantial between using estimated and observed LAVI. CONCLUSIONS: LV diastolic function can be evaluated with estimated LAVI from LAAPI, which might provide a surrogate method when the direct measurement of LAV is not available.

Incremental value of three-dimensional echocardiography for evaluating left atrial function in patients with coronary slow flow phenomenon: a case control study.

BACKGROUND: Coronary slow flow phenomenon (CSFP) involves the delayed opacification of the coronary distal vessel, in the absence of an obstructive lesion in the epicardial coronary artery during angiography. Since the link between left atrial (LA) function and decreased left ventricular function is still unclear, we evaluated LA function using real-time three-dimensional echocardiography (RT3DE) in patients with CSFP, and subsequently determined the incremental value of RT3DE. METHODS: This study enrolled 60 patients with CSFP and 45 control subjects. CSFP was diagnosed based on thrombolysis in myocardial infarction frame count (TFC). The LA phasic volume and function was evaluated by both two-dimensional echocardiography (2DE) and RT3DE. RESULTS: The LA maximal volume (Volmax), pre-systolic volume (Volp), and minimal volume (Volmin) increased, but LA total and active ejection fraction decreased in patients with CSFP. Based on our results, Volmax, Volp, Volmin, and LA total and active ejection fraction correlated with TFC, and with the number of arteries involved. The LA total ejection fraction by RT3DE was the only independent predictor for CSFP (odds ratio, 0.64 [95% confidence interval, 0.49-0.83]; P = 0.001). Also, the LA total ejection fraction by RT3DE demonstrated good predictive power for CSFP, with a cut-off value of 54.15% (area under curve, 0.85; sensitivity, 84%; specificity, 83%). CONCLUSIONS: The LA reservoir and contractile function decreased in the patients with CSFP and correlated with coronary flow rate and with the number of arteries involved. The LA total ejection fraction by RT3DE can independently predict CSFP, and RT3DE demonstrated incremental value for evaluating LA phasic function in the patients with CSFP compared to 2DE.

Bicuspid aortic valve with right-sided aortic arch aneurysm and Kommerell's diverticulum.

Bicuspid aortic valve (BAV) is a common congenital cardiac malformation, frequently combined with ascending aorta dilation. However, isolated abnormalities of the aortic arch are less frequent in BAV patients. Here, we present a rare case of BAV combined with right-sided aortic arch aneurysm, aberrant left subclavian artery, and Kommerell's diverticulum, diagnosed by echocardiography and computed tomography angiography. The patient was followed-up regularly because of the life-threatening risks of aortic arch aneurysms.

Incremental values of AOPP, IL-6, and GDF15 for identifying arteriosclerosis in patients with obstructive sleep apnea.

BACKGROUND: The objective of this study was to determine the independent and incremental values of advanced oxidative protein product (AOPP), interleukin 6 (IL-6), and growth differentiation factor 15 (GDF15) in identifying arteriosclerosis in patients with obstructive sleep apnea (OSA). METHODS: A total of 104 individuals diagnosed with OSA by polysomnography were recruited in our study. Arteriosclerosis was defined by measuring the ultrafast pulse wave velocity of the carotid artery. Peripheral venous blood samples were collected to analyze the levels of AOPP, IL-6, and GDF15 utilizing commercially available enzyme-linked immunosorbent assays. RESULTS: Compared to OSA patients without arteriosclerosis, those with arteriosclerosis exhibited significantly higher levels of AOPP, IL-6, and GDF15. GDF15 remained significantly associated with arteriosclerosis even after accounting for clinical factors such as age, gender, body mass index, systolic blood pressure, fasting blood glucose, smoking, and the apnea-hypoxia index (AHI). GDF15 demonstrated the largest area under the curve (AUC) for identifying arteriosclerosis in OSA patients (AUC, 0.85 [0.77-0.94]). The logistic regression model, combining clinical factors and AHI, was enhanced by the inclusion of AOPP and IL-6 (Chi-square = 25.06), and even further improved when GDF15 was added (Chi-square = 50.74). The integrated discrimination index increased by 0.06 to 0.16 when GDF15 was added to the models including clinical factors, AOPP, and IL-6. CONCLUSIONS: This study verified the independent and incremental value of GDF15 in identifying arteriosclerosis in OSA patients, surpassing clinical risk factors and other serum biomarkers such as AOPP and IL-6.

Soluble Vascular Cell Adhesion Molecule-1 as an Inflammation-Related Biomarker of Coronary Slow Flow.

Background: Coronary slow flow (CSF) is an angiographic entity characterized by delayed coronary opacification with no evident obstructive lesion in the epicardial coronary artery. Several studies have shown that the occurrence and development of CSF may be closely related to inflammation. Soluble vascular cell adhesion molecule-1 (sVCAM-1) is a biomarker related to inflammation. The aim of this study was to evaluate the correlation between plasma soluble VCAM-1 level and CSF occurrence and thus the predictive value of VCAM-1 for CSF. Methods: Forty-six CSF patients and thirty control subjects were enrolled. Corrected thrombolysis in myocardial infarction frame count (cTFC) was used to diagnose CSF. Functional status and quality of life were determined by the Seattle Angina Questionnaire (SAQ). Echocardiography was used to evaluate the systolic and diastolic function of the left ventricle (LV) and right ventricle (RV). The plasma levels of sVCAM-1, IL-6, and TNF-α were quantified by enzyme-linked immunosorbent assay. Results: Compared with the control group, the physical limitation score by the SAQ, the LV global longitudinal strain (GLS), mitral E, and mitral E/A decreased in patients with CSF, while the plasma IL-6 and TNF-α levels increased. The plasma sVCAM-1 level in the CSF group was significantly higher than that in the control group (186.03 ± 83.21 vs. 82.43 ± 42.12 ng/mL, p < 0.001), positively correlated with mean cTFC (r = 0.57, p < 0.001), and negatively correlated with the physical limitation score (r = −0.32, p = 0.004). Logistic regression analyses confirmed that plasma sVCAM-1 level (OR = 1.07, 95%CI: 1.03−1.11) is an independent predictor of CSF, and the receiver operating characteristic curve analysis showed that plasma sVCAM-1 levels had statistical significance in predicting CSF (area under curve = 0.88, p < 0.001). When the sVCAM-1 level was higher than 111.57 ng/mL, the sensitivity for predicting CSF was 87% and the specificity was 73%. Conclusions: Plasma sVCAM-1 level can be used to predict CSF and was associated with the clinical symptoms of patients. It may serve as a potential biomarker for CSF in the future.

Usefulness of soluble endothelial protein C receptor combined with left ventricular global longitudinal strain for predicting slow coronary flow: A case-control study.

BACKGROUND: Slow coronary flow (SCF) is an angiographic entity characterized by delayed coronary opacification without an evident obstructive lesion in the epicardial coronary artery. However, patients with SCF have decreased left ventricular (LV) global longitudinal strain (GLS). SCF is associated with inflammation, and soluble endothelial protein C receptor (sEPCR) is a potential biomarker of inflammation. Therefore, under evaluation herein, was the relationship between SCF and sEPCR and the predictive value of sEPCR and LV GLS for SCF was investigated. METHODS: Twenty-eight patients with SCF and 34 controls were enrolled. SCF was diagnosed by the thrombolysis in myocardial infarction frame count (TFC). The plasma level of sEPCR was quantified using enzyme-linked immunosorbent assay. LV GLS was measured by two-dimensional speckle-tracking echocardiography. RESULTS: Plasma sEPCR was significantly higher in patients with SCF than in controls and was positively correlated with the mean TFC (r = 0.67, p < 0.001) and number of involved vessels (r = 0.61, p < 0.001). LV GLS was decreased in patients with SCF compared to that in controls. sEPCR level (OR = 3.14, 95% CI 1.55-6.36, p = 0.001) and LV GLS (OR = 1.44, 95% CI 1.02-2.04, p = 0.04) were independent predictors of SCF. sEPCR predicted SCF (area under curve [AUC]: 0.83); however, sEPCR > 9.63 ng/mL combined with LV GLS > -14.36% demonstrated better predictive power (AUC: 0.89; sensitivity: 75%; specificity: 91%). CONCLUSIONS: Patients with SCF have increased plasma sEPCR and decreased LV GLS. sEPCR may be a useful potential biomarker for SCF, and sEPCR combined with LV GLS can better predict SCF.

Understanding the pathogenesis of coronary slow flow: Recent advances.

Coronary slow flow is taken to be indicative of delayed filling of terminal vessels of the coronary arteries in the absence of coronary stenosis, as detected using coronary angiography. Patients suffering from coronary slow flow typically experience recurrent chest pain, thereby markedly affecting their quality of life. The etiology and pathogenesis of coronary slow flow, which is gradually attracting clinical attention, have yet to be sufficiently established, although it is currently believed that they may be associated with endothelial dysfunction in the coronary arteries, inflammatory response, abnormalities in microvascular reserve function, subclinical atherosclerosis, blood cell and platelet abnormalities, and genetic factors. In this review, we provide a brief overview of recent progress in research on the pathogenesis of coronary slow flow with a view toward elucidating the possible underlying pathogenesis and identify targets and directions for the treatment of this condition.

Predictive value of HMGB1 for atrial fibrillation recurrence after cryoballoon ablation in paroxysmal atrial fibrillation patients.

BACKGROUND: Cryoballoon ablation (CBA) is recommended for patients with symptomatic drug refractory paroxysmal atrial fibrillation (pAF). However, substantial atrial fibrillation (AF) recurrence is common during follow-up. Searching for a potential biomarker representing both myocardial injury and inflammation to identify patients at high risk of AF recurrence after CBA is very meaningful for postoperative management of AF patients. HYPOTHESIS: To evaluate the clinical efficacy of high-mobility group box 1 (HMGB1) protein released from the left atrium to predict AF recurrence in pAF patients after CBA at 1-year follow-up. METHODS: We included 72 pAF patients who underwent CBA. To determine the expression levels of HMGB1, left atrial blood samples were collected from the patients before CBA and after the procedure through the transseptal sheath. Patients were followed up for AF recurrence for 1 year. RESULTS: A total of 19 patients of the 72 experienced AF recurrence. The level of postoperative HMGB1 (HMGB1post) was higher in the AF recurrence group than in the AF non recurrence group (p = .03). However, no differences were noted in the levels of other biomarkers such as preoperative high-sensitivity C-reactive protein (hs-CRP), postoperativehs-CRP, and preoperative HMGB1 between the two groups. Multiple logistic regression analysis revealed that a higher level of serum HMGB1post was associated with AF recurrence (odds ratio: 5.29 [1.17-23.92], p = .04). Receiver operating characteristic analysis revealed that HMGB1post had a moderate predictive power for AF recurrence (area under the curve: 0.68; sensitivity: 72%; and specificity: 68%). The 1-year AF-free survival was significantly lower in patients with a high HMGB1post level than in those with a low HMGB1post level (hazard ratio: 3.81 [1.49-9.75], p = .005). CONCLUSION: In pAF patients who under went CBA, the level of HMGB1 after CBA was associated with AF recurrence and demonstrated a moderate predictive power. Thus, we offer a potential biomarker to identify pAF patients at high risk of AF recurrence.

LncRNA NEAT1 Promote Inflammatory Responses in Coronary Slow Flow Through Regulating miR-148b-3p/ICAM-1 Axis.

BACKGROUND: Coronary slow flow (CSF) is an angiographic phenomenon characterized by delayed coronary opacification with normal or near-normal epicardial coronary arteries. The pathogenesis of CSF is closely related to inflammatory response. Accumulating evidence shows that long non-coding RNAs (lncRNAs) play an important role in cardiovascular disease. However, the mechanism underlying the influence of the lncRNA nuclear enriched abundant transcripts 1 (NEAT1) on CSF is still unknown. PATIENTS AND METHODS: Forty CSF patients and forty control subjects were included in the study and underwent coronary angiography, Seattle angina questionnaire (SAQ) and echocardiography. The plasma levels of the inflammatory factors soluble intercellular adhesion molecule-1 (sICAM-1), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were determined by ELISA. The expression levels of NEAT1, miR-148b-3p and ICAM-1 in cells were measured by qRT-PCR or Western blotting. Cell proliferation was measured by 5-Ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected by apoptosis assay. The relationship between NEAT1 and miR-148b-3p was verified by luciferase reporter gene assay, RNA immunoprecipitation (RIP) assay and avidin-biotin pull-down assay. The relationship between ICAM-1 and miR-148b-3p was verified by luciferase reporter gene assay and avidin-biotin pull-down assay. RESULTS: This study showed that plasma sICAM-1, miR-148b-3p, and NEAT1 as independent predictors of a CSF diagnosis. Furthermore, plasma NEAT1 level showed superior diagnostic ability for CSF compared with sICAM-1 and miR-148b-3p. It was also shown that high expression of NEAT1 in oxygen-glucose deprivation (OGD)-treated human umbilical vein endothelial cells (HUVECs) functions as a competing endogenous RNA (ceRNA). By specifically binding miR-148b-3p, it weakened the negative regulatory effects of miR-148b-3p on the ICAM-1 target gene leading to upregulated expression of ICAM-1. This interaction was also shown to inhibit HUVEC proliferation and enhance apoptosis. CONCLUSION: This study demonstrated for the first time the important mechanism of action of the NEAT1/miR-148b-3p/ICAM-1 axis in the progression of CSF disease, and indicated the potential of NEAT1, miR-148b-3p, and ICAM-1 as a new target for the diagnosis and treatment of CSF.

Sweroside Protects Against Myocardial Ischemia-Reperfusion Injury by Inhibiting Oxidative Stress and Pyroptosis Partially via Modulation of the Keap1/Nrf2 Axis.

Aims: Sweroside, a secoiridoid glucoside extracted from Swertia pseudochinensis Hara, is reported to possess antioxidant and anti-inflammatory activities. However, whether sweroside has a protective effect on myocardial ischemia-reperfusion (IR) injury is yet to be elucidated. The present study aimed to confirm the cardioprotective effect of sweroside and to identify its underlying mechanism. Methods and Results: H9c2 cells were pretreated with sweroside and then underwent hypoxia-reoxygenation. Cell Counting Kit-8, creatine kinase-myocardial band (CK-MB) and lactate dehydrogenase (LDH) assays were conducted to detect cell viability and myocardial injury, respectively. The Langendorff method was used to induce myocardial IR injury ex vivo. Triphenyltetrazolium chloride staining was performed to detect myocardial infarct size, while protein expression was analyzed using western blotting. Overall, the results indicated that sweroside pretreatment dose-dependently led to a significant enhancement in cell viability, a decrease in release of CK-MB and LDH, a reduction in infarct size, and an improvement in cardiac function. Additionally, sweroside pretreatment caused a marked suppression of oxidative stress, as evidenced by the fact that sweroside decreased the accumulation of reactive oxygen species and malondialdehyde, while enhancing the activities of superoxide dismutase and glutathione peroxidase. Moreover, sweroside was found to notably repress pyroptosis, as sweroside blocked pore formation in the cell membrane, inhibited caspase-1 and interleukin (IL)-1ß activity, and decreased the expression levels of NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD, cleaved caspase-1, and IL-1ß. Mechanistically, it was found that sweroside inhibited Kelch-like ECH-associated protein 1 (Keap1) and induced nuclear factor E2-associated factor 2 (Nrf2) nuclear translocation. Furthermore, the inhibition of oxidative stress and pyroptosis by sweroside could be abrogated via the inhibition of Nrf2 expression, which suggested that the protective effect induced by sweroside was Nrf2-dependent. Conclusions: The present study demonstrated that sweroside pretreatment could protect against myocardial IR injury by inhibiting of oxidative stress and NLRP3 inflammasome-mediated pyroptosis partially via modulation of the Keap1/Nrf2 axis.

The lncRNA MALAT1 participates in regulating coronary slow flow endothelial dysfunction through the miR-181b-5p-MEF2A-ET-1 axis.

BACKGROUND: Coronary slow flow (CSF) refers to coronary arteries with no obvious stenosis but have slow coronary flow without effective treatment. The main cause of CSF is endothelial dysfunction. The long non-coding RNA (lncRNA) MALAT1 is involved in regulating endothelial dysfunction, but its role in CSF endothelial dysfunction is still unclear. METHODS: We included 41 CSF patients and 37 controls in the study, who all underwent coronary angiography, echocardiography, and brachial artery flow-mediated dilatation (FMD) examination. Human umbilical vein endothelial cells (HUVECs) stimulated by oxygen-glucose deprivation were used as CSF-induced HUVECs. Plasma endothelin-1 (ET-1) concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The expression levels of MALAT1, miR-181b-5p, myocyte enhancer factor 2A (MEF2A), and ET-1 were measured by qRT-PCR or western blotting. Cell proliferation was determined by 5-ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. Apoptosis was examined by flow cytometry. The relationship between miR-181b-5p and MALAT1 or MEF2A was verified by dual-luciferase reporter assay. MEF2A binding directly to the ET-1 promoter region was verified via chromatin immunoprecipitation (ChIP) assay. RESULTS: MALAT1 and ET-1 were increased, and miR-181b-5p was decreased in the peripheral blood of the CSF patients, and could be used as predictors of CSF. In the CSF-induced HUVECs, MALAT1 was highly expressed, and MALAT1 knockdown improved endothelial function. In contrast, miR-181b-5p was downregulated in the CSF-induced HUVECs, and miR-181b-5p overexpression improved endothelial function. While MEF2A was highly enriched in CSF-induced HUVECs, MEF2A knockdown reduced ET-1 and increased the endothelial function of CSF-induced HUVECs as a transcriptional regulator of ET-1. MALAT1 modulated MEF2A expression positively by sponging miR-181b-5p. CONCLUSIONS: Endothelial function is reduced in CSF. MALAT1 participates in regulating CSF endothelial dysfunction through the miR-181b-5p-MEF2A-ET-1 axis, and could provide a new target for CSF treatment.

Incremental value of carotid elasticity modulus using shear wave elastography for identifying coronary artery disease in patients without carotid plaque.

BACKGROUND: Shear wave elastography (SWE) directly quantifies the local arterial wall stiffness by calculating the elastic modulus. However, whether carotid wall elastic modulus can predict obstructive coronary artery disease (CAD) is not well known. We aimed to investigate the value of carotid wall elastic modulus measured using SWE in identifying obstructive CAD. MATERIALS AND METHODS: We prospectively enrolled 61 patients without carotid plaque referred for clinically indicated coronary angiography. Twenty-seven (44.3%) patients were diagnosed with obstructive CAD (≥50% coronary stenosis). The elastic modulus of common carotid artery was quantified using SWE. Ankle--brachial index (ABI) and echocardiographic global cardiac calcium score (GCCS) were measured. RESULTS: Patients with obstructive CAD had significantly higher elastic modulus than those without obstructive CAD. The maximum elastic modulus (EMmax) was independently associated with obstructive CAD after adjusting for the Framingham risk score, ABI, and GCCS. EMmax had the highest area under the curve (AUC) to identify obstructive CAD (AUC 0.70; P = 0.003). In the nested models, the model based on the Framingham risk score and ABI (χ2 = 3.74) improved by adding GCCS (χ2 = 9.95) and further improved by adding EMmax (χ2 = 15.86). Adding EMmax to the combined ABI and GCCS model increased integrated discrimination index from 0.10 to 0.19. CONCLUSION: Carotid wall elastic modulus measured using SWE is a useful predictor of obstructive CAD in patients without carotid plaque. We demonstrated the incremental and independent value of carotid wall elastic modulus in identifying obstructive CAD compared with clinical risk factors and other imaging predictors, including ABI and GCCS. VIDEO ABSTRACT: Please see the video, in Supplemental Digital Content 1, http://links.lww.com/HJH/B551 for more insights from the authors.

Cardiac contractility modulation improves left ventricular systolic function partially via miR-25 mediated SERCA2A expression in rabbit trans aortic constriction heart failure model.

The purpose of this study was to investigate the underlying mechanism of cardiac contractility modulation (CCM) in improving trans aortic constriction (TAC)-induced heart failure (HF) left ventricular (LV) systolic function. A total of 25 New Zealand white rabbits were randomly divided into 5 groups: sham operation group (SHM), TAC-induced HF group (HF), TAC-induced HF followed by CCM stimulation group (HF + CCM), TAC-induced HF followed by injection of anti-miR-25 group (HF + anti-miR-25), TAC-induced HF followed by CCM stimulation and AAV9-miR-25 injection group (HF + CCM + miR-25). CCM current was performed 6 hours a day for 4 weeks. The left ventricle ejection fraction (LVEF) was measured by ultrasound. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used for measuring RNA and protein levels. The sarcoplasmic reticulum calcium ATPase (SERCA2A) and LVEF were reduced, while the miR-25 expression was improved in HF group compared to SHM group. Conversely, the SERCA2A and LVEF were improved, and the miR-25 reduced in the HF + CCM and the HF + anti-miR-25 groups compared to the HF group. Moreover, the SERCA2A and LVEF were reduced, while the miR-25 was improved in the HF + CCM + miR-25 group compared to the HF + CCM group. CCM is a potentially effective procedure for improving LV systolic function, which might partially by inhibiting miR-25 expression, further improved SERCA2A expression in TAC HF models.

Downregulation of growth arrest­specific transcript 5 alleviates palmitic acid­induced myocardial inflammatory injury through the miR­26a/HMGB1/NF­κB axis.

Palmitic acid (PA) can induce lipotoxic damage to cardiomyocytes, although its precise mechanism of action has not been completely elucidated. Growth arrest­specific transcript 5 (GAS5) is a long noncoding RNA that serves a regulatory role in several pathological processes, including tumorigenesis, stroke, cardiac fibrosis and osteoarthritis; however, its role in PA­induced myocardial injury remains elusive. The present study aimed to explore the role and underlying mechanism of GAS5 on PA­induced myocardial injury. The expression of GAS5 in PA­treated cardiomyocytes (H9c2 cells) was detected by reverse transcription­quantitative polymerase chain reaction (RT­qPCR), and its effects on PA­induced myocardial injury were measured by Cell Counting Kit­8 and lactate dehydrogenase (LDH) assays. The activities of cytokines and nuclear factor (NF)­κB were also detected by enzyme­linked immunosorbent assay, while interactions between GAS5 and microRNA (miR)­26a were evaluated by luciferase reporter assay and RT­qPCR. The regulation of GAS5 on high mobility group box 1 (HMGB1) expression was detected by RT­qPCR and western blotting. The results demonstrated that GAS5 was significantly upregulated in cardiomyocytes following treatment with PA. GAS5­knockdown increased the viability of PA­treated cardiomyocytes and reduced the activity of LDH, tumor necrosis factor­α and interleukin­1ß. Furthermore, the present study identified that GAS5 specifically binds to miR­26a, and a reciprocal negative regulation exists between the two. The present study also demonstrated that GAS5 downregulation inhibited HMGB1 expression and NF­κB activation, while these suppressive effects were mediated by miR­26a. In conclusion, the present study demonstrated that PA can induce GAS5 expression and that the downregulation of GAS5 alleviated PA­induced myocardial inflammatory injury through the miR­26a/HMGB1/NF­κB axis. These data may provide a novel insight into the mechanism of myocardial lipotoxic injury.