Guangxian Chen

Atrial fibrillation alters the microRNA expression profiles of the left atria of patients with mitral stenosis

BackgroundStructural changes of the left and right atria associated with atrial fibrillation (AF) in mitral stenosis (MS) patients are well known, and alterations in microRNA (miRNA) expression profiles of the right atria have also been investigated. However, miRNA changes in the left atria still require delineation. This study evaluated alterations in miRNA expression profiles of left atrial tissues from MS patients with AF relative to those with normal sinus rhythm (NSR).MethodsSample tissues from left atrial appendages were obtained from 12 MS patients (6 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Results were validated via reverse-transcription and quantitative PCR for 5 selected miRNAs. Potential miRNA targets were predicted and their functions and potential pathways analyzed via the miRFocus database.ResultsThe expression levels of 22 miRNAs differed between the AF and NSR groups. Relative to NSR patients, in those with AF the expression levels of 45% (10/22) of these miRNAs were significantly higher, while those of the balance (55%, 12/22) were significantly lower. Potential miRNA targets and molecular pathways were identified.ConclusionsAF alters the miRNA expression profiles of the left atria of MS patients. These findings may be useful for the biological understanding of AF in MS patients.

Ellagic acid prevents monocrotaline-induced pulmonary artery hypertension via inhibiting NLRP3 inflammasome activation in rats.

BACKGROUND Pulmonary artery hypertension (PAH) is characterized by vascular remodeling, high pulmonary blood pressure, and right ventricular hypertrophy. Oxidative stress, inflammation and pulmonary artery remodeling are important components in PAH. Ellagic acid (EA) is a phenolic compound with anti-oxidative, anti-inflammatory, and anti-proliferative properties. This study aimed to investigate whether EA could prevent the development of monocrotaline (MCT)-induced PAH in rats. METHODS Male Sprague-Dawley rats received EA (30 and 50mg/kg/day) or vehicle one day after a single-dose of monocrotaline (MCT, 60mg/kg). Hemodynamic changes, right ventricular hypertrophy, and lung morphological features were assessed 4weeks later. Activation of the NLRP3 (NACHT, LRR, and PYD domain-containing protein 3) inflammasome pathway in the lungs was assessed using Western blot analysis. RESULTS MCT induced PAH, oxidative stress, and NLRP3 inflammasome activation in vehicle-treated rats. EA reduced the right ventricle systolic pressure, the right ventricular hypertrophy and the wall thickness/external diameter ratio of the pulmonary arteries compared with vehicle. EA also inhibited the MCT-induced elevation of oxidative stress, NLRP3, and caspase-1, IL-β in the lungs and the elevated levels of brain natriuretic peptide (BNP) and inflammatory cytokines in serum. CONCLUSIONS Ellagic acid ameliorates monocrotaline-induced pulmonary artery hypertension via exerting its anti-oxidative property inhibiting NLRP3 inflammasome signal pathway in rats.

Comparative expression profiles of microRNA in left and right atrial appendages from patients with rheumatic mitral valve disease exhibiting sinus rhythm or atrial fibrillation

BackgroundThe atrial fibrillation (AF) associated microRNAs (miRNAs) were found in the right atrium (RA) and left atrium (LA) from patients with rheumatic mitral valve disease (RMVD). However, most studies only focus on the RA; and the potential differences of AF-associated miRNAs between the RA and LA are still unknown. The aim of this study was to perform miRNA expression profiles analysis to compare the potential differences of AF-associated miRNAs in the right atrial appendages (RAA) and left atrial appendages (LAA) from RMVD patients.MethodsSamples tissues from the RAA and LAA were obtained from 18 RMVD patients (10 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Then, the results were validated using qRT-PCR analysis for 12 selected miRNAs. Finally, potential targets of 10 validated miRNAs were predicted and their functions and potential pathways were analyzed using the miRFocus database.ResultsIn RAA, 65 AF-associated miRNAs were found and significantly dysregulated (i.e. 28 miRNAs were up-regulated and 37 were down-regulated). In LAA, 42 AF-associated miRNAs were found and significantly dysregulated (i.e. 22 miRNAs were up-regulated and 20 were down-regulated). Among these AF-associated miRNAs, 23 of them were found in both RAA and LAA, 45 of them were found only in RAA, and 19 of them were found only in LAA. Finally, 10 AF-associated miRNAs validated by qRT-PCR were similarly distributed in RAA and LAA; 3 were found in both RAA and LAA, 5 were found only in RAA, and 2 were found only in LAA. Potential miRNA targets and molecular pathways were identified.ConclusionsWe have found the different distributions of AF-associated miRNAs in the RAA and LAA from RMVD patients. This may reflect different miRNA mechanisms in AF between the RA and LA. These findings may provide new insights into the underlying mechanisms of AF in RMVD patients.

Controlled oxygen reperfusion protects the lung against early ischemia-reperfusion injury in cardiopulmonary bypasses by downregulating high mobility group box 1

ABSTRACT Restricting oxygen delivery during the reperfusion phase of cardiopulmonary bypass (CPB) protects the heart, but effects on lung ischemia reperfusion (IR) in CPB are unknown. We examined whether extracellular high mobility group box 1 (HMGB1) mediated inflammation during early lung IR injury in CPB. Fourteen healthy canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest, followed by 90 minutes reperfusion. Following surgery, the animals were randomized into control (n = 7) or test (n = 7) groups. Control animals received a constant level of 80% FiO2 during the entire procedure, and the test group received a gradual increase in FiO2 during the first 25 minutes of reperfusion. In the test group, the FiO2 was initiated at 40% and increased by 10% every 5 minutes, to 80%. Histology, lung injury variables, HMGB1 expression, and inflammatory responses were assessed at baseline (T1) and at 25 minutes (T2) and 90 minutes (T3) after starting reperfusion. Treatment with controlled oxygen significantly suppressed lung pathologies, lung injury variables, and inflammatory responses (all P < .001). After lung IR injury, HMGB1 mRNA and protein expressions were significantly decreased in the controlled oxygen group (all P < .001). Controlled oxygen reperfusion is protective in the early stages of lung IR injury in a canine CPB model, and this protection is linked to HMGB1 downregulation.

Simvastatin attenuates pulmonary vascular remodelling by down-regulating matrix metalloproteinase-1 and -9 expression in a carotid artery–jugular vein shunt pulmonary hypertension model in rats

OBJECTIVES It remains controversial as to whether simvastatin has a beneficial effect on pulmonary artery hypertension. This study aimed to explore the efficacy of simvastatin on haemodynamic changes, pulmonary vascular remodelling and expression of matrix metalloproteinase-1 and -9 (MMP-1,9) in a carotid artery-jugular vein (CA-JV) shunt pulmonary artery hypertension (PAH) model in rats. METHODS Thirty-six Sprague-Dawley rats were randomized into three groups: Control group, CA-JV group, and Treatment group. A pre-tricuspid systemic-pulmonary shunt from the left common carotid artery to the external jugular vein was established on the CA-JV and Treatment groups, but only ligations of both vessels were performed in Control group. Simvastatin (4 mg/kg/d) was administered to the Treatment group, and placebo to the CA-JV group. Twelve weeks later, the animals underwent a haemodynamic evaluation, followed by pulmonary tissue sampling for morphometry, quantitative real-time PCR and Western blot analysis. RESULTS By week 12, rats in the CA-JV group had higher right ventricular systolic pressure (RVSP), medial area/total area (MA/TA) and percentage of fibrous tissue (F%) than those in the Control group. These changes were associated with up-regulation of MMP-1,9 mRNA and increased expression of MMP-1,9 proteins. Pretreatment with simvastatin decreased the shunt-induced RVSP, MA/TA and F% in pulmonary arteries. In addition, lung MMP-1,9 mRNA and proteins levels decreased toward normal levels in simvastatin-treated rats. CONCLUSIONS Simvastatin ameliorated the structural and functional derangements of pulmonary arterioles caused by the CA-JV shunt, partly associated with the suppression of up-regulated MMP-1, as well as MMP-9. Simvastatin may play a role in the treatment of systemic-pulmonary shunt-induced PAH diseases, such as congenital heart disease.

Selective antegrade cerebral perfusion attenuating the TLR4/NF-κB pathway during deep hypothermia circulatory arrest in a pig model.

Objectives: The alteration of the Toll-like receptor/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway during deep hypothermia circulatory arrest (DHCA) has not yet been defined. The aim of this study was to explore the expression of the TLR4/NF-κB pathway cytokine in cerebral injury resulting from DHCA as well as the effect of selective antegrade cerebral perfusion (SACP) on TLR4/NF-κB pathway expression. Methods: Twelve pigs were randomly assigned to DHCA alone (n = 6) or DHCA with SACP (n = 6) at 18°C for 80 min. Serum interleukin (IL)-6 was assayed by ELISA. Apoptosis and NF-κB proteins were detected by fluorescence TUNEL and Western blot, respectively. The level of TLR4 mRNA and protein were determined through qRT-PCR and Western blot. Results: The serum IL-6 level of the SACP group was significantly lower than that of the DHCA group at the end of circulation arrest and experimentation. Apoptotic index and NF-κB protein were apparently lower in SACP animals (p < 0.05). Compared to the DHCA group, the levels of TLR4 protein and mRNA in the SACP group were lower with significance (p < 0.05). Conclusions: The TLR4/NF-κB signaling pathway plays a critical role in the pathogenesis of DHCA cerebral injury. Attenuation of the TLR4/NF-κB inflammatory cytokines probably contributes to the neuroprotective effect of SACP. The TLR4/NF-κB inflammatory signaling pathway may be a novel therapeutic target for developing a new strategy for neuroprotection in DHCA.

Is selective antegrade cerebral perfusion superior to retrograde cerebral perfusion for brain protection during deep hypothermic circulatory arrest? Metabolic evidence from microdialysis.

Objectives:This study aimed to investigate whether selective antegrade cerebral perfusion or retrograde cerebral perfusion is a better technique for brain protection in deep hypothermic circulatory arrest by obtaining metabolic evidence from microdialysis. Design:Randomized, animal study. Setting:Assisted circulation laboratory. Subjects:Eighteen piglets of either sex (9.8 ± 3.1 kg). Interventions:Animals were randomly assigned to 40 minutes of circulatory arrest at 18°C without cerebral perfusion (deep hypothermic circulatory arrest group, n = 6) or with selective antegrade cerebral perfusion (selective antegrade cerebral perfusion group, n = 6) or retrograde cerebral perfusion (retrograde cerebral perfusion group, n = 6). Reperfusion was continued for 3 hours. Measurements and Main Results:Microdialysis (glucose, lactate, pyruvate, and glycerol) variables in the cortex dialysate were measured every 30 minutes. Intracerebral pressure and serum S-100 levels were also monitored. After 3 hours of reperfusion, cortical tissue was harvested for terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. After 40 minutes of circulatory arrest, the deep hypothermic circulatory arrest group presented marked elevations of intracerebral pressure, and serum S-100 levels were higher in the deep hypothermic circulatory arrest group than in the other two groups (p < 0.001, respectively). The selective antegrade cerebral perfusion group exhibited higher glucose, lower lactate, and lower glycerol levels and a lower lactate-to-pyruvate ratio in comparison to the deep hypothermic circulatory arrest group (p < 0.05, respectively); the retrograde cerebral perfusion group had lower lactate and glycerol levels and a lower lactate-to-pyruvate ratio (p < 0.05, respectively) but similar glucose levels compared to deep hypothermic circulatory arrest alone. Furthermore, selective antegrade cerebral perfusion provided better preservation of energy and cell integrity than retrograde cerebral perfusion with higher glucose and lower glycerol levels (p < 0.05, respectively). After 3 hours of reperfusion, fewer apoptotic neurons were found in selective antegrade cerebral perfusion animals than in the other two groups (p < 0.05, respectively). Conclusions:Both selective antegrade cerebral perfusion and retrograde cerebral perfusion were superior to deep hypothermic circulatory arrest alone during circulatory arrest. Retrograde cerebral perfusion was a moderate technique that had similar advantages with regard to less cerebral edema, better clearance of metabolic waste, and lower levels of biomarkers of injury than selective antegrade cerebral perfusion, but its capacity for energy preservation, maintenance of cellular integrity, and protection against apoptosis was lower than that of selective antegrade cerebral perfusion.

Receptor for advanced glycation end products involved in lung ischemia reperfusion injury in cardiopulmonary bypass attenuated by controlled oxygen reperfusion in a canine model.

Controlled oxygen reperfusion could protect the lung against ischemia-reperfusion injury in cardiopulmonary bypass (CPB) by downregulating high mobility group box 1 (HMGB1), a high affinity receptor of HMGB1. This study investigated the effect of controlled oxygen reperfusion on receptor for advanced glycation end products (RAGE) expression and its downstream effects on lung ischemia-reperfusion injury. Fourteen canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest followed by 90 minutes of reperfusion. Animals were randomized to receive 80% FiO2 during the entire procedure (control group) or to a test group receiving a controlled oxygen reperfusion protocol. Pathologic changes in lung tissues, RAGE expression, serum interleukin-6 (IL-6), and tumor necrosis factor-&agr; (TNF-&agr;) were evaluated. The lung pathologic scores after 25 and 90 minutes of reperfusion were significantly lower in the test group compared with the control group (p < 0.001). RAGE expression, TNF-&agr;, and IL-6 were downregulated by controlled oxygen treatment (p < 0.001). RAGE might be involved in the lung ischemia-reperfusion injury in canine model of CPB, which was downregulated by controlled oxygen reperfusion.

MicroRNA profiling of the intestine during hypothermic circulatory arrest in swine

AIM To perform a profiling analysis of changes in intestinal microRNA (miRNA) expression during hypothermic circulatory arrest (HCA). METHODS A total of eight piglets were randomly divided into HCA and sham operation (SO) groups. Under general anesthesia, swine in the HCA group were subjected to hypothermic cardiopulmonary bypass at 24 °C followed by 80 min of circulatory arrest, and the reperfusion lasted for 180 min after cross-clamp removal. The counterparts in the SO group were only subjected to median sternotomy. Histopathological analysis was used to detect mucosal injury, and Pick-and-Mix custom miRNA real-time polymerase chain reaction (PCR) panels containing 306 unique primer sets were utilized to assay unpooled intestinal samples harvested from the two groups. RESULTS The intestinal mucosa of the animals that were subjected to 24 °C HCA exhibited representative ischemic reperfusion injury of grade 2 or 3 according to the Chiu score. Such intestinal mucosal injuries, with the subepithelial space and epithelial layer lifting away from the lamina propria, were accompanied by shortened and irregular villi. On the contrary, the intestinal mucosa remained normal in the sham-operated animals. In total, twenty-five miRNAs were differentially expressed between the two groups (15 upregulated and 10 downregulated in the HCA group). Among these, eight miRNAs (miR-122, miR-221-5p, miR-31, miR-421-5p, miR-4333, miR-499-3p, miR-542 and let-7d-3p) were significantly dysregulated (four higher and four lower). The expression of miR-122 was significantly (5.37-fold) increased in the HCA group vs the SO group, indicating that it may play a key role in HCA-induced mucosal injury. CONCLUSION Exposure to HCA caused intestinal miRNA dysregulation and barrier dysfunction in swine. These altered miRNAs might be related to the protection or destruction of the intestinal barrier.

Differences in atrial fibrillation‑associated proteins between the left and right atrial appendages from patients with rheumatic mitral valve disease: A comparative proteomic analysis Corrigendum in /10.3892/mmr.2018.9218

The majority of proteomic studies have focused on identifying atrial fibrillation (AF)-associated proteins in the right atrium (RA), thus potential differences in AF-associated proteins between the RA and left atrium (LA) remain unknown. The aim of the present study was to perform proteomic analysis to compare the potential differences in AF-associated proteins between the right atrial appendage (RAA) and left atrial appendage (LAA) in patients with rheumatic mitral valve disease (RMVD). RAA and LAA tissues were obtained from 18 patients with RMVD (10 with AF) during mitral valve replacement surgery. Two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) proteomics analysis was performed using these tissues to identify AF-associated proteins in RAA and LAA. Subsequently, the proteomics data was validated using western blot analysis of nine selected proteins. In RAA, 32 AF-associated proteins were significantly dysregulated (15 upregulated and 17 downregulated). In LAA, 31 AF-associated proteins were significantly dysregulated (13 upregulated and 18 downregulated). Among these AF-associated proteins, 17 were AF-associated in both RAA and LAA, 15 were AF-associated only in RAA, and 14 were AF-associated only in LAA. Amongst the differentially expressed proteins, western blot analysis validated the results for 6 AF-associated proteins, and demonstrated similar distributions in RAA and LAA compared with the 2-D DIGE results. Of these proteins, 2 proteins were AF-associated in both RAA and LAA, 2 were AF-associated only in RAA, and 2 were AF-associated only in LAA. Additionally, the different distributions of AF-associated proteins in the RAA and LAA of patients with RMVD was analyzed, which may reflect the different regulatory mechanisms of the RA and LA in AF. These findings may provide new insights into the underlying molecular mechanisms of AF in patients with RMVD.