Comparison of transesophageal echocardiography findings after different anticoagulation strategies in patients with atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: High risk of embolic events exists in both patients with chronic atrial fibrillation (AF) and patients in the perioperative period of ablation (effective treatment for AF). Therefore, anticoagulant therapy is important. Oral anticoagulants can be divided into two major categories: vitamin K antagonists (VKAs) and non-vitamin K antagonist oral anticoagulants (NOACs). VKAs, represented by warfarin, have been widely used as traditional anticoagulants, whereas NOACs have been used in clinical practice, but their anticoagulant effects and side effects are still the focus of research. We used a meta-analysis to compare the incidence of left atrial thrombi (LAT) between different anticoagulants. METHODS: We searched PubMed, EMBASE, Web of Science, and the Cochrane Library databases for observational studies that compared the transesophageal echocardiography (TEE) findings for patients treated with NOACs and VKAs. The incidence of LAT and dense spontaneous echocardiographic contrast (dense SEC) were extracted as the basis of the meta-analysis. RESULTS: Fifteen studies were included in the meta-analysis. We found that patients anticoagulated with NOACs and VKAs had similar incidence of LAT (OR = 0.74, 95%CI: 0.55-1.00). After excluding the heterogeneous article by sensitivity analysis, we found the incidence of LAT in patients anticoagulated with NOACs is lower than VKAs (OR = 0.59, 95%CI: 0.42-0.84). The results of subgroup analysis showed that the incidence of LAT among three types of NOACs have no significant difference (dabigatran vs. rivaroxaban, OR = 1.16 [0.75, 1.81]; rivaroxaban vs. apixaban, OR = 0.97 [0.54, 1.74]; dabigatran vs. apixaban, OR = 1.09 [0.55, 2.16]). CONCLUSION: Patients anticoagulated with NOACs may have lower incidence of LAT than VKAs. The incidence of LAT among different type of NOACs are similar.

The Role of RhoA in Neovascular-Related Functions of Endothelial Progenitor Cells Induced by Angiotensinâ ¡.

BACKGROUND/AIMS: Interference with endothelial progenitor cell (EPC) neovascularization is a novel therapeutic target for neovascular-related diseases. Angiotensin Ⅱ (Ang Ⅱ) was found to enhance new vessel formation and aggravated neovascular-related diseases. In this study, we investigated the effects of Ang Ⅱ on EPC neovascular-related functions and explored the underlying mechanisms. METHODS: EPCs were cultured from bone marrow derived mononuclear cells. The effects of Ang Ⅱ on EPC proliferation, adhesion, migration, and in vitro tube formation were investigated using the MTT assay, adhesion assay, transwell chamber assay, and in vitro tube formation assay respectively. The underlying mechanisms were explored using Western blotting assay. RESULTS: EPC adhesion, migration and in vitro tube formation were promoted by Ang Ⅱ, and the effects were reversed by RhoA/Rho-associated kinases (ROCK) signaling pathway inhibitors including C3 exoenzyme, GGTI-286 and Y-27632. The active form of RhoA was up-regulated by Ang Ⅱ and this effect was abolished by C3 exoenzyme. Moreover, RhoA silencing resulted in a notable inhibition of EPC adhesion, migration and in vitro tube formation, suggesting that RhoA activation played a pivotal role in Ang Ⅱ angiogenic effect. The results also demonstrated that phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun-NH2 kinase was elevated by Ang Ⅱ and attenuated by C3 exoenzyme, GGTI-286 and Y-27632. The enhancing effects of Ang Ⅱ on EPC adhesion, migration and in vitro vasculogenesis were reversed by p38 inhibitor SB202190 and JNK inhibitor SP600125. CONCLUSION: Ang Ⅱ may enhance EPC neovascular-related functions through activating RhoA/ ROCK and MAPK signaling pathway.

Abnormal expression of long non-coding RNAs in myocardial infarction.

Myocardial infarction (MI) is the leading cause of fatality worldwide. Our study aimed to investigate the dysregulated long non-coding RNA (lncRNA) in MI and elucidate the mechanism of it in MI. The lncRNA and mRNA expression profiling of the whole left ventricular tissue of MI mice model (8 mice) and Sham group (8 mice) was obtained based on microarray analysis. Differentially expressed lnRNAs/mRNA (DELs/DEMs) were identified in MI. DELs/DEMs co-expression network construction, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted to predict the biological functions of DEMs. Quantitative real-time polymerase chain reaction (qRT-PCR) was subjected to validate the abnormally expressed DELs in left ventricular tissues of MI mice model. Total of 168 DELs (37 up- and 131 down-regulated) and 126 DEMs (87 up- and 39 down-regulated) were identified in MI compared with Sham group. The co-expression network of candidate DELs and DEMs was constructed, which covered 219 nodes and 1775 edges. The qRT-PCR validation results indicated that ENSMUST00000124047 was significantly down-regulated in MI group and AK166279 was significantly up-regulated in MI group. ENSMUST00000121611 and NR_015515 had the up-regulated tendency in MI group compared with Sham group. The DEMs in MI were significantly enriched in 41 signaling pathways including complement and coagulation cascades, cytokine-cytokine receptor interaction and chemokine signaling pathway. The expression profiling of dysregulated DELs in MI was identified. Our results might provide useful information for exploring the pathogenesis mechanism of MI.

Autophagy protects against senescence and apoptosis via the RAS-mitochondria in high-glucose-induced endothelial cells.

BACKGROUNDS: Autophagy is an important process in the pathogenesis of diabetes and plays a critical role in maintaining cellular homeostasis. However, the autophagic response and its mechanism in diabetic vascular endothelium remain unclear. METHODS AND RESULTS: We studied high-glucose-induced renin-angiotensin system (RAS)-mitochondrial damage and its effect on endothelial cells. With regard to therapeutics, we investigated the beneficial effect of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) against high-glucose-induced endothelial responses. High glucose activated RAS, enhanced mitochondrial damage and increased senescence, apoptosis and autophagic-responses in endothelial cells, and these effects were mimicked by using angiotensin II (Ang). The use of an ACEI or ARB, however, inhibited the negative effects of high glucose. Direct mitochondrial injury caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) resulted in similar negative effects of high glucose or Ang and abrogated the protective effects of an ACEI or ARB. Additionally, by impairing autophagy, high-glucose-induced senescence and apoptosis were accelerated and the ACEI- or ARB-mediated beneficial effects were abolished. Furthermore, increases in FragEL™ DNA Fragmentation (TUNEL)-positive cells, ß-galactosidase activation and the expression of autophagic biomarkers were revealed in diabetic patients and rats, and the treatment with an ACEI or ARB decreased these responses. CONCLUSIONS: These data suggest that autophagy protects against senescence and apoptosis via RAS-mitochondria in high-glucose-induced endothelial cells.

Alteration of mevalonate pathway related enzyme expressions in pressure overload-induced cardiac hypertrophy and associated heart failure with preserved ejection fraction.

BACKGROUND: Abnormalities of the mevalonate pathway, an important cellular metabolic pathway, are common in many diseases including cardiovascular disease. The mevalonate pathway related enzyme expressions in pressure overload-induced cardiac hypertrophy and associated diastolic dysfunction remains largely unknown. This study aims to investigate whether the expression of mevalonate pathway related enzyme is altered during the progression of cardiac hypertrophy and associated diastolic dysfunction induced by pressure overload. METHODS: Male Sprague-Dawley (SD) rats were randomly divided into two groups: the suprarenal abdominal aortic coarctation (AAC) group and the sham group. RESULTS: Histological and echocardiographic assessments showed that there was a significant cardiovascular remodeling in the AAC group compared with the sham group after 3 weeks post-operatively, and the left ventricular (LV) diastolic function was reduced at 8 and 14 weeks post-operatively in the AAC group, without any change in systolic function during the study. The tissue of the heart and the abdominal aorta proximal to the coarctation showed over-expression of several enzymes, including 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), farnesyl diphosphate synthase (FDPS), farnesyltransferase-α (FNTA), farnesyltransferase-ß (FNTB), geranylgeranyltransferase type I (GGTase-I) and the activation of their downstream proteins was enhanced. CONCLUSIONS: AAC induced compensatory LV hypertrophy to decompensatory diastolic dysfunction, accompanied by altered expression of several key enzymes in the mevalonate pathway.

Phospholamban antisense RNA improves SR Ca2+-ATPase activity and left ventricular function in STZ-induced diabetic rats.

OBJECTIVE: To study the effect of phospholamban antisense RNA (asPLB) on sarcoplasmic reticulum Ca2+-ATPase activity and cardiac function in rats with diabetes mellitus (DM) mediated by recombinant adeno-associated virus (rAAV) vector. METHODS: Six weeks after the induction of DM by streptozotocin injected intraperitoneally, the rats were divided into three groups, namely: DM-rAAV-asPLB group, DM-saline group and DM group (control group). The rats in the DM-rAAV-asPLB group were intramyocardially injected with rAAV-asPLB, the rats in the DM-saline group were injected with saline, and those in the control group did not receive any treatment. Six weeks after gene transfer, the expressions of PLB protein and PLB phosphorylation were detected by Western-blot, while the activity of sarcoplasmic reticulum (SR) Ca2+-ATPase and left ventricular function were measured. RESULTS: The PLB protein expression level was significantly higher whereas the PLB phosphorylation, SR Ca2+-ATPase activity and left ventricular function were significantly lower in the DM-saline group than in the control group. No significant difference was found in PLB protein expression level, PLB phosphorylation or SR Ca2+-ATPase activity between the DM-rAAV-asPLB group and the control group. The left ventricular function in the DM-rAAV-asPLB group was poorer than in the control group and was better than in the DM-saline group. CONCLUSION: rAAV-asPLB can down-regulate PLB protein expression and up-regulate PLB phosphorylation and SR Ca2+-ATPase activity, thus contributing to the improvement of in vivo left ventricular function.

Effect of microRNA-34a in cell cycle, differentiation, and apoptosis: a review.

The tumor suppressor gene p53 was shown to directly regulate the expression of microRNA-34a (miR-34a). miR-34a regulates a plethora of target proteins, which are involved in cell cycle, apoptosis, differentiation, and cellular development.miR-34a resides in the region of chromosome 1p36.23, which is commonly deleted in many tumor types, while it results in the loss expression of miR-34a. The promoters of the miR-34a gene subject to inactivation by CpG methylation also induce the loss expression of miR-34a. Ectopic miR-34a expression induces apoptosis, cell cycle arrest, and differentiation or reduces migration. This review summarizes the progress regarding the role of miR-34a in cell cycle, differentiation, and apoptosis.

Alteration of enzyme expressions in mevalonate pathway: possible role for cardiovascular remodeling in spontaneously hypertensive rats.

BACKGROUND: The mevalonate pathway is an important metabolic pathway that plays a key role in multiple cellular processes. The aim of this study was to define whether the enzyme expression in mevalonate pathway changes during cardiovascular remodelling in spontaneously hypertensive rats (SHR). METHODS AND RESULTS: Hearts and thoracic aortas were removed for the study of cardiovascular remodeling in SHR and Wistar-Kyoto rats (WKY). The protein expression of the enzymes in hearts, aortas and livers was analyzed by western blot. The histological measurements showed that the mass and the size of cardiomyocytes, the media thickness and the media cross-sectional area (MCSA) of the thoracic aorta were all increased in SHR since 3 weeks of age. In the heart, there was overexpression of some enzymes, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), farnesyl diphosphate synthase (FDPS), and geranylgeranyltransferase type I (GGTase-I), and downregulation of squalene synthetase (SQS) in SHR since 3 weeks of age. In the aorta, besides similar expressions of HMGR, SQS, FDPS and GGTase-I as in the heart, there was upregulation of farnesyltransferase α at 16 and 25 weeks of age and of farnesyltransferase ß in 25-weeks-old SHR. Western blot demonstrated overexpression of HMGR and downregulation of SQS in SHR livers at all ages tested. CONCLUSIONS: The cardiovascular remodeling of SHR preceded the development of hypertension, and altered expression of several key enzymes in the mevalonate pathway may play a potential pathophysiological role in cardiovascular remodeling.

Establishment of transgenic mice carrying the gene for farnesyl pyrophosphate synthase.

Farnesyl pyrophosphate synthase (FPPS) is an essential enzyme in the mevalonate pathway and might be relevant to hypertension and other cardiovascular diseases. FPPS transgenic mice were produced by microinjecting a construct with the FPPS gene into fertilized eggs derived from an inbred C57BL/6 strain. Three mice were identified as carrying copies of the transgene using the PCR. Reverse transcription PCR and Western blotting showed that the transgene was expressed in heart, liver, lung, ear, brain, thymus, and blood vessels in the transgenic mouse. Pathological analysis (hematoxylin and eosin staining) showed that FPPS expression did not cause obvious pathological changes in multiple tissues of 6-week-old transgenic mice. This FPPS transgenic mouse model, may therefore, facilitate the investigation of the biological functions of FPPS in vivo.

The Correlation Between Whole Blood Copper (Cu), Zinc (Zn) Levels and Cu/Zn Ratio and Sepsis-Induced Left Ventricular Systolic Dysfunction (SILVSD) in Patients with Septic Shock: A Single-Center Prospective Observational Study.

PURPOSE: This study aimed to explore relationships between whole blood copper (Cu), zinc (Zn) and Cu/Zn ratio and cardiac dysfunction in patients with septic shock. SUBJECTS AND METHODS: Between April 2018 and March 2020, septic shock patients with sepsis-induced left ventricular systolic dysfunction (SILVSD, left ventricular ejection fraction, LVEF<50%) and with no sepsis-induced myocardial dysfunction (non-SIMD, septic shock alone and LVEF>50%) and controls were prospectively enrolled. Whole blood Cu and Zn levels were measured using flame atomic absorption spectrophotometry. RESULTS: Eighty-six patients with septic shock including both 41 SILVSD and 45 non-SIMD and 25 controls were studied. Whole blood Cu levels and Cu/Zn ratio were significantly higher and Zn levels were lower in SILVSD compared with non-SIMD and controls (Cu, p=0.009, <0.001; Zn, p=0.029, <0.001; Cu/Zn ratio, p=0.003, <0.001). Both increased whole blood Cu and Cu/Zn ratio and reduced Zn were associated with lower LVEF (all p<0.001) and higher amino-terminal pro-B-type natriuretic peptide (NT-proBNP) (Cu, p=0.002; Zn, p<0.001; Cu/Zn ratio, p<0.001) and had predictive values for SILVSD (Cu, AUC=0.666, p=0.005; Zn, AUC=0.625, p=0.039; Cu/Zn ratio, AUC=0.674, p=0.029). Whole blood Cu levels and Cu/Zn ratio were increased but Zn levels were reduced in non-survivors compared with survivors (Cu, p<0.001; Zn, p<0.001; Cu/Zn ratio, p<0.001). Whole blood Cu and Zn displayed the value of predicting 28-day mortality (Cu, AUC = 0.802, p<0.001; Zn, AUC=0.869, p<0.001; Cu/Zn ratio, AUC=0.902, p<0.001). CONCLUSION: Findings of the study suggest that whole blood Cu levels and Cu/Zn ratio are increased in SILVSD patients and positively correlated with cardiac dysfunction, while whole blood Zn levels are reduced and negatively associated with cardiac dysfunction. Moreover, both whole blood Cu, Zn and Cu/Zn ratio might distinguish between SILVSD and non-SIMD in septic shock patients and predict 28-day mortality. TRIAL REGISTRATION: Registered at http://www.chictr.org.cn/ChiCTR1800015709.

Identification and Functional Prediction of Long Non-Coding RNAs in Dilated Cardiomyopathy by Bioinformatics Analysis.

Dilated cardiomyopathy (DCM) is a relatively common cause of heart failure and the leading cause of heart transplantation. Aberrant changes in long non-coding RNAs (lncRNAs) are involved in DCM disorder; however, the detailed mechanisms underlying DCM initiation and progression require further investigation, and new molecular targets are needed. Here, we obtained lncRNA-expression profiles associated with DCM and non-failing hearts through microarray probe-sequence re-annotation. Weighted gene co-expression network analysis revealed a module highly associated with DCM status. Then eight hub lncRNAs in this module (FGD5-AS1, AC009113.1, WDFY3-AS2, NIFK-AS1, ZNF571-AS1, MIR100HG, AC079089.1, and EIF3J-AS1) were identified. All hub lncRNAs except ZNF571-AS1 were predicted as localizing to the cytoplasm. As a possible mechanism of DCM pathogenesis, we predicted that these hub lncRNAs might exert functions by acting as competing endogenous RNAs (ceRNAs). Furthermore, we found that the above results can be essentially reproduced in an independent external dataset. We observed the localization of hub lncRNAs by RNA-FISH in human aortic smooth muscle cells and confirmed the upregulation of the hub lncRNAs in DCM patients through quantitative RT-PCR. In conclusion, these findings identified eight candidate lncRNAs associated with DCM disease and revealed their potential involvement in DCM partly through ceRNA crosstalk. Our results facilitate the discovery of therapeutic targets and enhance the understanding of DCM pathogenesis.

Dual effects of sodium aescinate on vascular tension in rat thoracic aorta.

OBJECTIVE: Sodium aescinate (SA) is used as a vasoactive drug in clinical treatment. This study was designed to investigate the effects of SA on rat isolated thoracic aorta and the possible mechanisms. METHODS: Isometric tension was recorded in response to drugs in organ bath. RESULTS: The effects of SA obeyed an all-or-nothing response. SA in relatively low dose (> or = 50 microg/ml) had an endothelium-independent contractile effect in rat aorta (P<0.01), which depended on extracellular Ca(2+) influx via L-type Ca(2+) channel (P<0.05). SA in relatively high dose (> or = 100 microg/ml) also induced vasoconstriction in Ca(2+)-free medium (P<0.01), which was independent of the activity of inositol-1,4,5-trisphosphate receptor (IP(3)R), ryanodine receptor (RYR), and protein kinase C (PKC). SA in relatively high dose (> or = 100 microg/ml) dilated both endothelium-intact and endothelium-denuded aortic rings precontracted by phenylephrine (PE) or KCl (each P<0.01). SA inhibited extracellular Ca(2+) influx induced by PE or KCl (each P<0.01) and had no activation effect on K(+) channels on vascular smooth muscle. The relaxant effect of SA partly depended on the activity of NO synthase but not on the activity of cyclooxygenase. CONCLUSIONS: Taken together, this study indicated that SA had dual effects on vascular tension in rat isolated thoracic aorta.

MicroRNA­125a­mediated regulation of the mevalonate signaling pathway contributes to high glucose­induced proliferation and migration of vascular smooth muscle cells.

Hyperglycemia contributes to the excessive proliferation and migration of vascular smooth muscle cells (VSMC), which are closely associated with atherosclerosis. MicroRNAs (miRNAs/miRs) constitute a novel class of gene regulators, which have important roles in various pathological conditions. The aim of the present study was to identify miRNAs involved in the high glucose (HG)­induced VSMC phenotype switch, and to investigate the underlying mechanism. miRNA sequencing and reverse transcription­quantitative PCR results indicated that inhibition of miR­125a expression increased the migration and proliferation of VSMCs following HG exposure, whereas the overexpression of miR­125a abrogated this effect. Furthermore, dual­luciferase reporter assay results identified that 3­hydroxy­3-methyglutaryl­coA reductase (HMGCR), one of the key enzymes in the mevalonate signaling pathway, is a target of miR­125a. Moreover, HMGCR knockdown, similarly to miR­125a overexpression, suppressed HG­induced VSMC proliferation and migration. These results were consistent with those from the miRNA target prediction programs. Using a rat model of streptozotocin­induced diabetes mellitus, it was demonstrated that miR­125a expression was gradually downregulated, and that the expressions of key enzymes in the mevalonate signaling pathway in the aortic media were dysregulated after several weeks. In addition, it was found that HG­induced excessive activation of the mevalonate signaling pathway in VSMCs was suppressed following transfection with a miR­125a mimic. Therefore, the present results suggest that decreased miR­125a expression contributed to HG­induced VSMC proliferation and migration via the upregulation of HMGCR expression. Thus, miR­125a­mediated regulation of the mevalonate signaling pathway may be associated with atherosclerosis.

A Variant in the Nicotinic Acetylcholine Receptor Alpha 3 Subunit Gene Is Associated With Hypertension Risks in Hypogonadic Patients.

Ephb6 gene knockout causes hypertension in castrated mice. EPHB6 controls catecholamine secretion by adrenal gland chromaffin cells (AGCCs) in a testosterone-dependent way. Nicotinic acetylcholine receptor (nAChR) is a ligand-gated Ca2+/Na+ channel, and its opening is the first signaling event leading to catecholamine secretion by AGCCs. There is a possibility that nAChR might be involved in EPHB6 signaling, and thus sequence variants of its subunit genes are associated with hypertension risks. CHRNA3 is the major subunit of nAChR used in human and mouse AGCCs. We conducted a human genetic study to assess the association of CHRNA3 variants with hypertension risks in hypogonadic males. The study cohort included 1,500 hypogonadic Chinese males with (750 patients) or without (750 patients) hypertension. The result revealed that SNV rs3743076 in the fourth intron of CHRNA3 was significantly associated with hypertension risks in the hypogonadic males. We further showed that EPHB6 physically interacted with CHRNA3 in AGCCs, providing a molecular basis for nAChR being in the EPHB6 signaling pathway.

Effects of atorvastatin on calcium-regulating proteins: a possible mechanism to repair cardiac dysfunction in spontaneously hypertensive rats.

Previous clinical and experimental studies have demonstrated that statins, the inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, can improve left ventricular function in damaged hearts. Also, the normal expression of Ca(2+) regulatory proteins is critical for efficient myocardial function. However, it is still unclear whether the beneficial effect of statins on cardiac function is associated with alterations of Ca(2+) regulatory proteins. In this study, we investigated the effect of atorvastatin on cardiac function in spontaneously hypertensive rats (SHRs), focusing in particular on its impact on the expression of sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase (SERCA2a), phospholamban (PLB) and its phosphorylated form (phosphorylated PLB), all of which are Ca(2+) regulatory proteins in myocardium. SHRs showed decreases in gene expression of SERCA2a and phosphorylated PLB, and reduction in SERCA activity in the left ventricular myocardium, as well as reduced cardiac function, compared to age-matched Wistar Kyoto rats (WKYs). Furthermore, we showed that in SHRs atorvastatin preserved cardiac dysfunction accompanied by positive alterations in calcium regulatory proteins, with up-regulation in expression of SERCA2a and phosphorylated PLB, and with improvement of SERCA activity. Thus, atorvastatin has positive effects on calcium regulatory proteins, which may be one of the mechanisms of the beneficial effect of statins on cardiac function in spontaneously hypertensive rats.

Beneficial effect of rosuvastatin on cardiac dysfunction is associated with alterations in calcium-regulatory proteins.

AIMS: The normal expression of Ca(2+)-regulatory protein is critical for efficient myocardial function. The present study tested the hypothesis that rosuvastatin treatment may attenuate left ventricular (LV) remodelling and dysfunction in the failing heart, which may be associated with alterations of Ca(2+)-regulatory protein. METHODS AND RESULTS: We investigated the change of LV remodelling and function in a rat model of cardiac dysfunction due to myocardial infarction (MI) with or without rosuvastatin (10 mg/kg/day) treatment for 10 weeks. The protein expression of sarcoplasmic reticulum Ca(2+) ATPase (SERCA)2a, phospholamban (PLB), and phospho-PLB at serine-16 (pSer16-PLB), as well as SERCA activity, interleukin (IL)-6, and IL-10 levels were evaluated. After rosuvastatin treatment, LV remodelling and dysfunction were prevented. Rosuvastatin prevented the decrease of SERCA2a and pSer16-PLB expression, increased SERCA activity, but showed no effect on PLB expression. Furthermore, rosuvastatin reduced the increased IL-6 level and further elevated IL-10 level in the peri-infarct and remote zones of MI. Serum lipid levels remained unchanged. CONCLUSION: Rosuvastatin is effective in preventing LV remodelling and dysfunction in the failing heart. The molecular mechanism may be related to normalization of SERCA2a expression, SERCA activity, and pSer16-PLB levels, as well as through cytokine alterations independent of its lipid-lowering effect.

Endothelium-independent vasorelaxant effect of sodium ferulate on rat thoracic aorta.

AIMS: This study was designed to investigate the effects of sodium ferulate (SF) on rat isolated thoracic aortas and the possible mechanisms. MAIN METHODS: Isometric tension was recorded in response to drugs in organ bath. Cytosolic free Ca(2+) concentration ([Ca(2+)](i)) was measured using Fluo-3 in cultured rat aortic smooth muscle cells (RASMC). KEY FINDINGS: SF (0.1-30 mM) relaxed the isolated aortic rings precontracted with phenylephrine (PE) and high-K(+) in a concentration-dependent manner with respective pD(2) of 2.7+/-0.02 and 2.6+/-0.06. Mechanical removal of endothelium did not significantly modify the SF-induced relaxation. In Ca(2+)-free solution, SF noticeably inhibited extracellular Ca(2+)-induced contraction in high-K(+) and PE pre-challenged rings, and suppressed the transient contraction induced by PE and caffeine. The vasorelaxant effect of SF was unaffected by various K(+) channel blockers such as tetraethylammonium, glibenclamide, 4-aminopyridine, and barium chloride. In addition, SF concentration-dependently reduced the contraction induced by phorbol-12-myristate-13-acetate, an activator of protein kinase C (PKC), in the absence of extracellular Ca(2+), with the pD(2) of 2.9+/-0.03. In RASMC, SF had no effect on PE- or KCl-induced [Ca(2+)](i) increase either in the presence or in the absence of external Ca(2+). SIGNIFICANCE: These results indicate that SF acts directly as a non-selective relaxant to vascular smooth muscle. The direct inhibition of the common pathway after [Ca(2+)](i) increase may account for the SF-induced relaxation in Ca(2+)-dependent contraction, while the blockage of the PKC-mediated contractile mechanism is likely responsible for the SF-induced relaxation in Ca(2+)-independent contraction.

Cardioprotection by polysaccharide sulfate against ischemia/reperfusion injury in isolated rat hearts.

AIM: Polysaccharide sulfate (PSS) is a new type of heparinoid synthesized with alginic acid as the basic material and then by chemical introduction of effective groups. Although PSS is successfully applied in ischemic cardio-cerebrovascular disease, its effect on cardiac function after ischemia/reperfusion (I/R) injury has previously not been investigated. The aim of the present study was to investigate whether PSS can protect the heart from I/R injury and the underlying mechanism of protection. METHODS: Isolated rat hearts were perfused (Langendorff) and subjected to 20 min global ischemia followed by 60 min reperfusion with Kreb's Henseleit solution or PSS (0.3-100 mg/L). Myocardial contractile function was continuously recorded. Creatine kinase (CK) and lactate dehydrogenase (LDH) leakage were measured. Tumor necrosis factor-alpha (TNF-alpha) expression in cardiomyocytes was investigated. Western blot analysis for extracellular regulated kinases (ERKs), c-jun amino-terminal kinase (JNKs) and p38 mitogen-activated protein kinase (MAPK) activity was performed. RESULTS: After I/R, cardiac contractility decreased, CK and LDH levels increased in the coronary effluent, and TNF-alpha expression increased in cardiomyocytes. PSS administration at concentrations of 1-30 mg/L improved cardiac contractility, reduced CK and LDH release and inhibited TNF-alpha production. Phosphorylated-p38MAPK (p-p38MAPK) and p-p54/p46-JNK increased in I/R rat hearts but diminished in PSS (1-30 mg/L) treated hearts. P-p44/p42-ERK levels were unchanged. In contrast, high concentrations of PSS (100 mg/L) had adverse effects that caused a worsening of heart function. CONCLUSION: PSS has dose-dependent cardioprotective effects on the rat heart after I/R injury. The beneficial effects may be mediated through normalization of the activity of p38 MAPK and JNK pathways as well as controlling the level of TNF-alpha expression.

rAAV-asPLB transfer attenuates abnormal sarcoplasmic reticulum Ca2+ -ATPase activity and cardiac dysfunction in rats with myocardial infarction.

BACKGROUND: Diminished myocardial sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) activity and upregulated phospholamban (PLB) level during cardiac dysfunction, had been reported in many studies. AIMS: The current study was designed to examine the effects of rAAV-antisense phospholamban (asPLB) gene transfer on cardiac function, SERCA expression and activity, as well as PLB expression and phosphorylation (Pser16-PLB), in a rat myocardial infarction (MI) model. METHODS AND RESULTS: Rat MI model was generated by ligating the left anterior descending coronary artery. Four weeks later, left ventricular ejection fraction (LVEF), left ventricular systolic pressure (LVSP), the maximal rates of increase and decrease in intraventricular pressure (+/-dp/dt(max)) were significantly depressed, and left ventricular end diastolic pressure (LVEDP) was increased. Myocardial PLB was markedly increased while both SERCA activity and Pser16-PLB level were decreased. In rAAV-asPLB transfected rats, rAAV-asPLB, which was injected into the myocardium around the infarction area immediately after the coronary artery ligation, effectively attenuated the depression of cardiac function, significantly inhibited the expression of PLB, restored Pser16-PLB level and enhanced myocardium SERCA activity. CONCLUSION: rAAV-asPLB transfer in rats with MI effectively prevented the progression of heart failure.

Tissue-specific effects of atorvastatin on 3-hydroxy-3-methylglutarylcoenzyme A reductase expression and activity in spontaneously hypertensive rats.

AIM: Cardiovascular remodeling is closely associated with cholesterol and is attenuated by statins. The spontaneously hypertensive rat (SHR) has a low serum cholesterol level and evident cardiovascular remodeling. The aims of the present study were to characterize the effects of atorvastatin on tissue cholesterol content and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase expression and activity in four tissues from SHR: liver, heart, aorta and kidney. METHODS: SHR and normotensive Wistar-Kyoto rats (WKY) were treated daily with atorvastatin (50 mg/kg) for 8 weeks. Cholesterol levels of serum and tissues (liver, heart, aorta and kidney) were determined by commercial enzymatic methods. Western blot analysis and high performance liquid chromatogram (HPLC) were used to assay the expression and activity of enzyme respectively. RESULTS: Treatment with atorvastatin decreased cholesterol content and HMGCoA reductase expression and activity in all four tissues of SHR. However, in WKY, atorvastatin only altered HMG-CoA reductase in liver, where the protein expression was upregulated but the enzyme activity was decreased. CONCLUSION: The present study demonstrates that the effects of atorvastatin on tissue cholesterol content and HMG-CoA reductase are strain- and tissue-specific.