Associations of Renal Function Trajectories and Long-Term Cardiovascular Risks Among a Population Without Chronic Kidney Disease.

Background The longitudinal trajectories of renal function have been associated with cardiovascular events in patients with chronic kidney disease (CKD). However, the change pattern of renal function in those without CKD has not yet been reported. We aim to explore patterns of renal function change in a non-CKD population and its associated risks with cardiovascular outcomes. Methods and Results The present study analyzed data from 4 prospective cohorts and was restricted to participants without baseline CKD. The primary outcome was major adverse cardiovascular events, defined as a composite of myocardial infarction, chronic heart failure, stroke, and cardiovascular deaths. We used a group-based trajectory model to identify latent groups and analyzed the associated risk with Cox regression models. The complete dates of this study were June 1, 2020, through January 1, 2021. The final sample comprised 23 760 participants (mean age, 58.63 [9.12] years, 10 618 men, and 17 799 White participants). During 20.56 years follow-up, 8328 (35.05%) first major adverse cardiovascular events happened. Four trajectories in estimated glomerular renal function and 3 patterns of CKD progression were identified. Compared with subjects assigned to class I trajectory (high to mildly decreased group), the adjusted hazard ratios of major adverse cardiovascular events for class II (normal to mildly decreased group), class III (normal to moderately decreased group), and class IV (mildly to severely decreased group) were 1.11 (95% CI, 1.01-1.23), 1.27 (95% CI, 1.14-1.40), and 1.56 (95% CI, 1.38-1.77), respectively. Likewise, participants assigned to the slow and rapid progression groups had elevated HRs for major adverse cardiovascular events (1.75 [95% CI, 1.39-2.21] and 2.19 [95% CI, 1.68-2.86], respectively) when compared with the stable group. Findings were generally consistent in stratification analysis, but significant interaction effects by age and smoking status were detected. Conclusions In this study, we identified unique trajectory groups for renal function. These findings may signal an underlying high-risk population and inspire future studies on individualized risk management.

Phosphorylation of CaMK and CREB-Mediated Cardiac Aldosterone Synthesis Induced by Arginine Vasopressin in Rats with Myocardial Infarction.

Both aldosterone and arginine vasopressin (AVP) are produced in the heart and may participate in cardiac fibrosis. However, their relationship remains unknown. This study aims to demonstrate the regulation and role of AVP in aldosterone synthesis in the heart. Rats were subjected to a sham operation or myocardial infarction (MI) by ligating the coronary artery. Cardiac function and fibrosis were assessed using echocardiography and immunohistochemical staining, respectively. In addition, the effects of AVP stimulation on cardiac microvascular endothelial cells (CMECs) were studied using ELISA, real-time PCR, and Western blotting. Compared with the rats having undergone a sham operation, the MI rats had an increased LVMI, type I collagen composition, and concentrations of aldosterone and AVP in the heart but decreased cardiac function. As the MI rats aged, the LVMI, type I collagen, aldosterone, and AVP increased, while the LVMI decreased. Furthermore, AVP time-dependently induced aldosterone secretion and CYP11B2 mRNA expression in CMECs. The p-CREB levels were significantly increased by AVP. Nevertheless, these effects were completely blocked by SR49059 or partially inhibited by KN93. This study demonstrated that AVP could induce the secretion of local cardiac aldosterone, which may involve CaMK and CREB phosphorylation and CYP11B2 upregulation through V1 receptor activation.

CD51 distinguishes a subpopulation of bone marrow mesenchymal stem cells with distinct migratory potential: a novel cell-based strategy to treat acute myocardial infarction in mice.

BACKGROUND: Experimental and clinical trials have demonstrated the efficiency of bone marrow-derived mesenchymal stromal/stem cells (bMSCs) in the treatment of myocardial infarction. However, after intravenous injection, the ineffective migration of engrafted bMSCs to the hearts remains an obstacle, which has an undesirable impact on the efficiency of cell-based therapy. Therefore, we attempted to identify a marker that could distinguish a subpopulation of bMSCs with a promising migratory capacity. METHODS: Here, CD51-negative and CD51-positive cells were isolated by flow cytometry from Ter119-CD45-CD31-bMSCs and cultured in specifically modified medium. The proliferation ability of the cells was evaluated by 5-ethynyl-2'-deoxyuridine (EdU) staining or continuously monitored during culture, and the differentiation potential was assessed by culturing the cells in the appropriate conditioned media. Wound healing assays, transwell assays and quantitative polymerase chain reaction (qPCR) were used to measure the migratory ability. The mice were subjected to a sham operation or myocardial infarction (MI) by permanently occluding the coronary artery, and green fluorescent protein (GFP)-labelled cells were transplanted into the mice via intravenous infusion immediately after MI. Heart function was measured by echocardiography; infarct myocardium tissues were detected by triphenyl tetrazolium chloride (TTC) staining. Additionally, immunofluorescence staining was used to verify the characteristics of CD51+bMSCs and inflammatory responses in vivo. Statistical comparisons were performed using a two-tailed Student's t test. RESULTS: In this study, the isolated CD51-bMSCs and CD51+bMSCs, especially the CD51+ cells, presented a favourable proliferative capacity and could differentiate into adipocytes, osteocytes and chondrocytes in vitro. After the cells were transplanted into the MI mice by intravenous injection, the therapeutic efficiency of CD51+bMSCs in improving left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) was better than that of CD51-bMSCs. Compared with CD51-bMSCs, CD51+bMSCs preferentially migrated to and were retained in the infarcted hearts at 48 h and 8 days after intravenous injection. Accordingly, the migratory capacity of CD51+bMSCs exceeded that of CD51-bMSCs in vitro, and the former cells expressed higher levels of chemokine receptors or ligands. Interestingly, the retained CD51+bMSCs retained in the myocardium possessed proliferative potential but only differentiated into endothelial cells, smooth muscle cells, fibroblasts or cardiomyocytes. Transplantation of CD51+bMSCs partially attenuated the inflammatory response in the hearts after MI, while the potential for inflammatory suppression was low in CD51-bMSC-treated mice. CONCLUSIONS: These findings indicated that the CD51-distinguished subpopulation of bMSCs facilitated proliferation and migration both in vitro and in vivo, which provided a novel cell-based strategy to treat acute MI in mice by intravenous injection.

Spironolactone suppresses aldosterone-induced Kv1.5 expression by attenuating mineralocorticoid receptor-Nox1/2/4-mediated ROS generation in neonatal rat atrial myocytes.

Our previous investigation indicated that angiotensin II (Ang II) enhances the expression of Kv1.5, a promising target for the treatment of atrial fibrillation (AF), by activating reactive oxygen species (ROS)-dependent phosphorylation of Smad 2/3 (forming P-Smad 2/3) and ERK 1/2 (forming P-ERK 1/2). A recent study indicated that aldosterone (Aldo) upregulates atrial Kv1.5 protein in a rat AF model, but the mechanism remains unknown. The present study aimed to clarify the mechanism underlying Aldo-induced Kv1.5 expression and to test whether spironolactone may modulate atrial Kv1.5. Our Western blot analysis indicated that the Aldo/mineralocorticoid receptor (MR) interacts with Ang II/AT1R in upregulating Kv1.5 expression in cultured neonatal atrial myocytes (NRAMs). Blockade of MR with spironolactone and of AT1R with losartan significantly suppressed Kv1.5 expression induction by combined Aldo and Ang II treatment. Aldo increased the protein expression of Nox1, Nox2 and Nox4, but this effect was abolished by spironolactone pretreatment. The Aldo-induced upregulation of Kv1.5 was also reversed by the Src protein tyrosine kinase family inhibitor PP2, the Nox2 inhibitor gp91ds-tat and the Nox1/Nox4 inhibitor GKT137831 but not by the Rac GTPase inhibitor NSC23766. Flow cytometry showed that the Aldo-induced ROS production was inhibited by spironolactone, PP2, gp91ds-tat and GKT137831. Spironolactone suppressed the Aldo-induced protein expression phosphorylated Src (P-Src), P-Smad 2/3 and P-ERK 1/2. In conclusion, we have demonstrated that spironolactone suppresses Aldo-induced Kv1.5 expression by attenuating MR-Nox1/2/4-mediated ROS generation in NRAMs.

Inhibition of perivascular mast cell activation is involved in the atheroprotective effect of rosiglitazone in apolipoprotein E-deficient mice.

Activation of perivascular mast cells (MCs) and subsequent release of their abundant inflammatory mediators have been well documented to induce excessive inflammation and subsequent rupture of atherosclerotic plaques. Previous studies have suggested that rosiglitazone affects the stability of plaques, although the precise mechanism of action is not clearly understood. In this study, we evaluated the effects of rosiglitazone on MCs in vivo and in vitro. Apolipoprotein E-deficient (ApoE-/-) mice were fed a high-fat diet (HFD), with or without rosiglitazone supplemented in the drinking water (1.5 mg/kg/day). Compared with the HFD group, rosiglitazone did not affect blood glucose levels, but it attenuated serum levels of tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6), ameliorated plaque lipid accumulation and the expression of matrix metalloproteinases-2 and -9, increased the collagen content of plaques, and inhibited perivascular MC degranulation and chymase expression. The in vitro experiments showed that rosiglitazone treatment repressed the expression of TNFα and IL-6 induced by antigen-challenged RBL-2H3 cells in a peroxisome proliferator-activated receptor γ (PPARγ)-independent manner, which was related to the repression of protein kinase C (PKC)-ß1 activation. Combined, these results suggest that the plaque-stabilizing effect of rosiglitazone is attributable to its ability to inhibit the activation of perivascular MCs.

Correction to: Development of a new risk nomogram of perioperative major adverse cardiac events for Chinese patients undergoing colorectal carcinoma surgery.

On this article the authors requested to add another affiliation which is Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510,080, China for Juhong Zhang, Xiuren Gao and Zhibin Huang. The new affiliation is now added in this article. The remainder of the article remains unchanged.

Relationship and mechanism of Kv2.1 expression to ADH secretion in rats with heart failure.

OBJECTIVE: To explore the mechanisms of Kv2.1 on the secretion of ADH in rats with heart failure. METHODS: In the animal study, 70 healthy male SD rats were selected. Ligation of coronary heart failure model surgery was performed in 60 rats and sham surgery was performed in the other 10 rats. Q-PCR was used to detect the mRNA expression of Kv2.1 in hypothalamus and heart. The protein expression of Kv2.1 and ADH was detected by western blot. In the cell culture study, hypothalamic neurons were cultured and divided into 7 groups. The mRNA expression of Kv2.1 and ADH was detected by Q-PCR. The protein expression of Kv2.1, CamKII, phosphorylation SynapsinI, dephosphorylation SynapsinI and ADH was detected by western blot. RESULTS: Compared with the control group of heart failure, LVEDD, LVESD, LVEDV and LVESV were significantly decreased (P < 0.01), and LVEF and LVFS were significantly increased (P < 0.01) in the Kv2.1 agonist group; in the Kv2.1 inhibitor group, LVEDD, LVESD, LVEDV and LVESV were significantly increased (P < 0.01), and LVEF and LVFS were significantly decreased (P < 0.01). In cell culture study, after the different concentrations of Kv2.1 inhibitor gradient down the expression of Kv2.1, intracellular Ca2+ concentration gradient increased (P < 0.01), CamKII and phosphorylation of SynapsinI protein expression gradient increased (P < 0.01), dephosphorylation of SynapsinI protein expression gradient decreased (P < 0.01), and the ADH mRNA and protein expression of gradient increased (P < 0.01). CONCLUSIONS: Kv2.1 agonist can prevent the calcium overload by reducing the intracellular Ca2+ concentration, so that the phosphorylation of SynapsinI reduces and exocytosis in hypothalamic neurons is inhibited, which ease the secretion of ADH.

Selenium modulates MMP2 expression through the TGFß1/Smad signalling pathway in human umbilical vein endothelial cells and rabbits following lipid disturbance.

BACKGROUND: A high-fat diet is a major risk factor for coronary heart diseases. Matrix metalloprotease (MMP) expression is changed in many cardiovascular diseases. Selenium, which is an important trace element in animals, has a close relationship with cardiovascular diseases. The TGFß1/Smad signalling pathway is ubiquitous in diverse tissues and cells, and it is also associated with the occurrence and development of cardiovascular diseases. Therefore, in this study, we aimed to determine selenium's effect on lipid metabolism, atherosclerotic plaque formation, and MMP2 expression, as well as the underlying functional mechanism. METHODS AND RESULTS: In vivo tests: 24 male New Zealand white rabbits were randomly divided into 4 groups: regular diet, high-fat diet, high-fat diet+selenium and regular diet+selenium groups. The high-fat diet induced the lipid disturbances of rabbits at week 12. Selenium supplementation lowered total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels (p<0.01). Selenium supplementation also suppressed MMP2 over-expression in thoracic aortas. In vitro tests: Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of selenium or ox-LDL. Ox-LDL promoted MMP2 expression by increasing TGFß1, pSmad2, pSmad3 and Smad3 expression (p<0.01). Selenium attenuated MMP2 over-expression by regulating the TGFß1/Smad signalling pathway. CONCLUSIONS: Selenium suppressed high-fat diet-induced MMP2 over-expression in vivo by improving lipid metabolism. In vitro, selenium attenuated MMP2 over-expression through the TGFß1/Smad signalling pathway.

Development of a new risk nomogram of perioperative major adverse cardiac events for Chinese patients undergoing colorectal carcinoma surgery.

PURPOSE: The purpose of this study is to create a new risk nomogram to predict perioperative major adverse cardiac events in patients undergoing colorectal carcinoma surgery. METHODS: A total of 1899 patients who underwent colorectal carcinoma surgery at a tertiary teaching hospital in China between 2007 and 2012 were recruited. Logistic regression analysis was used to define risk factors for major adverse cardiac events. A nomogram-predicting model was built based on the logistic regression model and discrimination was tested by receiver operating characteristic curves. RESULTS: Fifty-six (2.9%) among 1899 included patients developed at least one cardiac event. Eight risk factors were found in the multivariate logistic regression model, which included age ≥60 years, smoking, a history of chronic kidney disease, coronary artery disease, congestive heart failure, hypertension, preoperative albumin levels ≤35 g/L, blood transfusion ≥500 mL, and intraoperative blood pressure variability. P = 0.708 in the Hosmer-Lemeshow test indicated acceptable calibration power. Based on this multivariate model, we built a risk nomogram model for these cardiac events with an area under the curve (95% confidence interval) of 0.923 (0.889, 0.957), which demonstrated good discrimination of this model. When the probability cutoff was 1.9% (total score of 83), the nomogram model had the best sensitivity and specificity in predicting cardiac events. CONCLUSIONS: A new nomogram model for predicting perioperative major adverse cardiac events in patients who had colorectal carcinoma surgery was established in this study. When the total score is >83, patients undergoing colorectal carcinoma surgery should be considered at high risk of perioperative major adverse cardiac events.

Hydrochlorothiazide modulates ischemic heart failure-induced cardiac remodeling via inhibiting angiotensin II type 1 receptor pathway in rats.

AIMS: Our previous study indicates that hydrochlorothiazide inhibits transforming growth factor (TGF)-ß/Smad signaling pathway, improves cardiac function and reduces fibrosis. We determined whether these effects were common among the diuretics and whether angiotensin II receptor type 1 (AT1) signaling pathway played a role in these effects. METHODS: Heart failure was produced by ligating the left anterior descending coronary artery in adult male Sprague Dawley rats. Two weeks after the ligation, 70 rats were randomly divided into five groups: sham-operated group, control group, valsartan group (80 mg/kg/d), hydrochlorothiazide group (12.5 mg/kg/d) and furosemide group (20 mg/kg/d). In addition, neonatal rat ventricular fibroblasts were treated with angiotensin II. RESULTS: After eight-week drug treatment, hydrochlorothiazide group and valsartan group but not furosemide group had improved cardiac function (ejection fraction was 49.4±2.1%, 49.5±1.8% and 39.9±1.9%, respectively, compared with 40.1±2.2% in control group), reduced cardiac interstitial fibrosis and collagen volume fraction (9.7±1.2%, 10.0±1.3% and 14.1±0.8%, respectively, compared with 15.9±1.1% in control group), and decreased expression of AT1, TGF-ß and Smad2 in the cardiac tissues. In addition, hydrochlorothiazide reduced plasma angiotensin II and aldosterone levels. Furthermore, hydrochlorothiazide inhibited angiotensin II-induced TGF-ß1 and Smad2 protein expression in the neonatal rat ventricular fibroblasts. CONCLUSIONS: Our study indicates that the cardiac function and remodeling improvement after ischemic heart failure may not be common among the diuretics. Hydrochlorothiazide may reduce the left ventricular wall stress and angiotensin II signaling pathway to provide these beneficial effects.

H2S inhibits angiotensin II-induced atrial Kv1.5 upregulation by attenuating Nox4-mediated ROS generation during atrial fibrillation.

Our previous study demonstrated that angiotensin II (Ang II) upregulates the expression of Kv1.5, a promising target for atrial fibrillation (AF) therapy, by activating ROS-dependent P-Smad2/3 and P-ERK 1/2. A recent study showed that hydrogen sulfide (H2S) may modulate the effects of angiotensin II (Ang II) by inhibiting the NADPH oxidase 4 (Nox4)-ROS signaling in the heart. The present study aimed to determine whether H2S is involved in the regulation of atrial Kv1.5 via ROS-related mechanisms in AF. Cultured neonatal rat atrial myocytes and a beagle model of AF were used for this study. In the neonatal rat atrial myocytes, quantitative PCR and enzyme immunoassays revealed that the mRNA expression levels of angiotensinogen, angiotensin-converting enzyme, and Ang II type I receptor (AT1R) and the Ang II supernatant concentration were significantly increased by hydrogen peroxide (H2O2) incubation, and these H2O2-induced alterations were reversed by diphenyleneiodonium, apocynin and H2S supplementation. Flow cytometry and Western blotting revealed that blockade of H2S biosynthesis using dl-propargylglycine increased ROS production and the expression of Ang II and Kv1.5. Sodium hydrosulfide (an exogenous H2S donor) and Nox4 siRNA inhibited Ang II-induced ROS production and Ang II-induced expression of Kv1.5, P-Smad2/3, P-ERK 1/2. Sodium hydrosulfide suppressed the Ang II-induced upregulation of Nox4. In our beagle AF model, 24 h of rapid atrial pacing (RAP) increased the atrial Ang II concentration, ROS production and the protein expression of Nox4, Kv1.5, P-Smad2/3 and P-ERK 1/2. These RAP-induced changes were inhibited by H2S supplementation and losartan (an AT1R blocker) pretreatment. In conclusion, our study indicates that H2S downregulates Ang II-induced atrial Kv1.5 expression by attenuating Nox4-related ROS-triggered P-Smad2/3 and P-ERK 1/2 activation during AF. H2S supplementation would be beneficial for AF treatment via the suppression of atrial Kv1.5 expression.

The Role of the Rho/ROCK Pathway in Ang II and TGF-ß1-Induced Atrial Remodeling.

OBJECTIVES: To study the role of the Rho/ROCK pathway in Ang II and TGF-ß1-induced atrial remodeling. METHODS AND RESULTS: A canine atrial fibrillation (AF) model was established by rapid atrial pacing (RAP) of the left atrium. The roles of TGF-ß1, the RhoA/ROCK signaling pathway and connective tissue growth factor (CTGF) in atrial remodeling were studied via both in vitro and in vivo experiments. Each of the dogs that received RAP developed persistent AF within 4 weeks. The mRNA expression levels of TGF-ß1 (1.32±0.38), Collagen-I(1.33±0.91), CTGF(5.83±3.71), RhoA(1.23±0.57) and ROCK-1 (1.02±0.27) in the left atrium were significantly increased following 4 weeks of RAP. Angiotensin II (Ang II) induced the proliferation of atrial fibroblasts and up-regulated the expression of both CTGF and ROCK-1 in a dose-dependent manner. Simvastatin and Y27632 reversed Ang II-induced CFs proliferation, as well as ROCK-1(0.89±0.05 and 1.27±0.03, respectively) and CTGF (0.87±0.04 and 0.91±0.02, respectively) expression. The expression mRNA of ROCK-1(1.74±0.13) and CTGF (2.28±0.11) can upregulated by TGF-ß1, and down-regulated by Simvastatin (1.22±0.03 vs 2.27±0.11), Y27632 (1.01±0.04 vs 1.64±0.03), Los (1.04±0.11 vs 1.26±0.05), respectively. Losartan and Simvastatin attenuated the effects of TGF-ß1, inhibited RhoA activity as opposed to RhoA protein expression. Y27632 had no effect on either the expression or the activity of RhoA. CONCLUSIONS: The increased expression of profibrotic factors (CTGF, ROCK1 and Smad2/3) played an important role in our RAP-induced AF model. Increased atrial profibrotic factors involve the activation of either the TGF-ß1/RhoA/ROCK-1 or the TGF-ß1/Smad2/3 signaling pathway.

Neuroprotective effect of lidocaine: is there clinical potential?

Local anesthetic lidocaine has been shown to be protective in animal models of focal and global ischemia as well as in in vitro hypoxic models. Lidocaine has been tested in patients for its potential protective effect on postoperative cognitive dysfunction. This mini-review summarizes the laboratory and clinical evidences and discusses its clinical applications as neuroprotective agent.

Downregulation of VEGF and upregulation of TL1A expression induce HUVEC apoptosis in response to high glucose stimuli.

High glucose­induced endothelial cell apoptosis is considered to be the initiator of diabetes­associated vascular complications. Experiments in vivo and in vitro have demonstrated that high glucose levels contribute to the apoptosis of endothelial cells by mediating cellular dysfunction and metabolic disorder via the production of various cytokines. As the most important endogenous vascular regulators, the balance between pro­proliferative effector vascular endothelial growth factor (VEGF) and anti­proliferative effector tumor necrosis factor­like cytokine 1A (TL1A) is important in the modulation of endothelial cell survival and proliferation, and neovascularization. The present study aimed to explore whether the imbalance between VEGF and TL1A affected the apoptosis of human umbilical vein endothelial cells (HUVECs) exposed to high glucose conditions and then further investigated the potential mechanism. The results showed that the downregulation of VEGF in combination with the upregulation of TL1A in response to high glucose levels led to enhanced HUVEC apoptosis. Further experiments revealed that silencing high glucose­induced TL1A expression using TL1A small interfering (si)RNA or the overexpression of VEGF by transfection with VEGF DNA resulted in a reduced HUVEC apoptosis rate compared with the controls. The effects occurred by attenuating and activating the phosphoinositide 3­kinase/Akt/endothelial nitric oxide synthase pathway, respectively. In addition, VEGF and TL1A inhibited each other in hyperglycemia. In conclusion, these findings provide theoretical support for the further investigation of novel therapeutic strategies designed to maintain the balance between VEGF and TL1A and, thus, to prevent the onset and progression of endothelial cell apoptosis in response to high glucose stimuli.

Rapid atrial pacing induces myocardial fibrosis by down-regulating Smad7 via microRNA-21 in rabbit.

Tachycardia-induced atrial fibrosis is a hallmark of the structural remodeling of atrial fibrillation (AF). The mechanisms underlying tachycardia-induced atrial fibrosis remain unclear. In our previous study, we found that Smad7-downregulation promoted the development of atrial fibrosis in AF. Fibroblasts are enriched in microRNA-21 (miR-21), which contributes to the development of fibrosis and heart failure in the cardiovascular system. Our study was designed to test the hypothesis that miR-21 reinforces the TGF-ß1/Smad signaling pathway in AF-induced atrial fibrosis by down-regulating Smad7. Rapid atrial pacing (RAP, 1000 ppm) was applied to the left atrium of the rabbit heart to induce atrial fibrillation and fibrosis. qRT-PCR and northern blot analysis revealed that RAP caused a marked increase in the expression of miR-21. Transfection with a miR-21 inhibitor significantly increased the expression of Smad7, while the expression of collagen I/III significantly decreased. These changes were implicated in the AF-induced release of miR-21 and down-regulation of Smad7. Adult rat cardiac fibroblasts treated with TGF-ß1 showed increased miR-21 expression and decreased Smad7 expression. Pretreatment with a TGF-ß1 inhibitor reduced the TGF-ß1-induced up-regulation of miR-21. Pretreatment with pre-miR-21 and a miR-21 inhibitor significantly decreased and increased Smad7 expression, respectively. This result was negatively correlated with the expression of collagen I/III in fibroblasts. Moreover, the results of a luciferase activity assay suggest that Smad7 is a validated miR-21 target in CFs. Our results provide compelling evidence that the miR-21 specific degradation of Smad7 may decrease the inhibitory feedback regulation of TGF-ß1/Smad signaling and serves as a new insight of the mechanism of atrial fibrosis in atrial fibrillation.

Atorvastatin Ameliorates Radiation-Induced Cardiac Fibrosis in Rats.

Radiation-induced heart injury is one of the major side effects of radiotherapy for thoracic malignancies. Previous studies have shown that radiotherapy induced myocardial fibrosis and intensified myocardial remodeling. In this study, we investigated whether atorvastatin could inhibit radiation-induced heart fibrosis in Sprague-Dawley rats, which were randomly divided into six groups: control; radiation only; and four treatment groups receiving atorvastatin plus radiation (E1, E2, E3 and E4). All rats, except the control group, received local heart irradiation in 7 daily fractions of 3 Gy for a total of 21 Gy. Rats in groups E1 (10 mg/kg/day) and E2 (20 mg/kg/day) received atorvastatin and radiation treatment until week 12 after exposure. Rats in groups E3 (10 mg/kg/day) and E4 (20 mg/kg/day) received atorvastatin treatment from 3 months before irradiation to week 12 after irradiation. The expressions of TGF-ß1, Smad2, Smad3, fibronectin, ROCK I and p-Akt in heart tissues were evaluated using real-time PCR or Western blot analyses. Atorvastatin significantly reduced the expression of TGF-ß1, Smad3/P-Smad3, ROCK I and p-Akt in rats of the E1-E4 groups and in a dose-dependent manner. Fibronectin exhibited a similar pattern of expression changes. In addition, echocardiography showed that atorvastatin treatment can inhibit the increase of left ventricular end-diastolic dimension, left ventricular end-systolic diameter and left ventricular posterior wall thickness, and prevent the decrease of ejection fraction and fraction shortening in E1-E4 groups compared with the radiation only group. This study demonstrated that radiation exposure increased the expression of fibronectin in cardiac fibroblasts and induced cardiac fibrosis through activation of the TGF-ß1/Smad3, RhoA/ROCK, and PI3K/AKT signaling pathways. Statins ameliorated radiation-induced cardiac fibrosis in Sprague-Dawley rats. Our results suggest that atorvastatin is effective for the treatment of radiation-induced cardiac fibrosis, especially with longer and higher dose atorvastatin treatment, as demonstrated in experimental group E4.

Zinc Regulates Lipid Metabolism and MMPs Expression in Lipid Disturbance Rabbits.

Lipid disturbance induced by high-fat diet is a worldwide problem, and it can induce inflammation and oxidative stress in vivo. Zinc is considered as an antioxidant, anti-inflammatory agent. Since matrix metalloprotease 2 (MMP2) and matrix metalloprotease 9 (MMP9)'s expressions are changed under many pathological conditions, we would like to know how zinc affects lipid metabolism and MMP2, MMP9's expressions in the lipid disturbance rabbits. Twenty-four male New Zealand white rabbits were randomly divided into four groups. Each group had six rabbits, and they were fed with regular diet, high-fat diet, high-fat diet+zinc, and regular diet+zinc separately for 12 weeks. High-fat diet induced lipid disturbance significantly which raised the level of aspartate aminotransferase (p<0.01) and alanine transaminase (p<0.05) in the high-fat diet group, but zinc supplement reversed this phenomenon (p<0.05). Zinc did not reduce total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) (p>0.05), but it lowered triglyceride (TG) and raised high-density lipoprotein cholesterol (HDL-C) (p<0.01). Zinc also reduced high-sensitivity C-reactive protein (hs-CRP) (p<0.01) and interleukin-6 (IL-6)'s expressions (p<0.05). Zinc reduced the epicardial adipose tissue and alleviated the hepatic steatosis. Zinc suppressed MMP2 and MMP9's expressions in vivo, but it did not alleviate the aorta fatty streak's severity in the lipid disturbance rabbits. Zinc protected the liver, reduced TG, hs-CRP, and IL-6 and raised HDL-C in the lipid disturbance rabbits. Zinc suppressed MMP2 and MMP9's expressions in vivo, but it did not alleviate the severity of aorta fatty streak induced by the high-fat diet.

The secretion patterns and roles of cardiac and circulating arginine vasopressin during the development of heart failure.

OBJECTIVE: The aim of this study is to investigate local cardiac and circulating AVP secretion during heart failure and to determine whether AVP mediates ventricular remodeling. METHODS: We assessed cardiac function and AVP levels of post-myocardial infarction (MI) heart-failure rats 3 weeks (n = 10), 4 weeks (n = 10), 6 weeks (n = 10), 9 weeks (n = 15) after the proximal left anterior descending coronary artery (LAD) ligation. Ten sham-operated rats were used as the control group. In vitro, cardiac microvascular endothelial cells (CMECs) were initiated from isolated Wistar rat hearts and subjected to Ang II to induce AVP expression and secretion. Besides, the effects of AVP stimulation on CMECs and cardiac fibroblasts (CFs) were studied using methylthiazol tetrazolium assay, Western blotting and real-time PCR. RESULTS: With cardiac dysfunction, plasma and local cardiac AVP, aldosterone levels increased over time, peaking at 9 weeks post-MI. AVP levels were negatively correlated with serum Na(+) and LVEF but positively correlated with LVEDD and myocardial hydroxyproline. In CMECs treated with Ang II, AVP mRNA and protein expression increased. In addition, AVP promoted CFs proliferation and up-regulated the expression of endothelin-1 and connective tissue growth factor. CONCLUSION: CMECs are the cellular sources of elevated local heart AVP stimulated with Ang II/AT1. An intrinsic cardiac AVP system exists. Local cardiac and circulating AVP secretion were enhanced by deteriorating cardiac function. AVP may promote ventricular remodeling. Thus, AVP could be an important mediator of myocardial fibrosis in late-stage heart failure.

Angiotensin II upregulates Kv1.5 expression through ROS-dependent transforming growth factor-beta1 and extracellular signal-regulated kinase 1/2 signalings in neonatal rat atrial myocytes.

Kv1.5 potassium channel represents a promising target for atrial fibrillation (AF) therapy. During AF, the renin-angiotensin system is markedly activated. Recent evidence indicates that angiotensin II (Ang II) can upregulate Kv1.5 channel, but the mechanism remains unknown. In this study, we report that Ang II-mediated transforming growth factor-beta1 (TGF-ß1)/Smad2/3 and extracellular signal-regulated kinase (ERK) 1/2 signalings are involved in atrial Kv1.5 expression. In neonatal rat atrial myocytes, quantitative PCR and Western blotting revealed that Ang II upregulated TGF-ß1, synapse-associated protein 97 (SAP97) and Kv1.5 expression in a time- and concentration-dependent manner. The Ang II-induced upregulation of Kv1.5, SAP97 and phosphorylated Smad2/3 (P-Smad2/3) were reversed by the Ang II type 1 (AT1) receptor antagonist losartan, an anti-TGF-ß1 antibody and the ERK 1/2 inhibitor PD98059 but not by the AT2 receptor antagonist PD123319. mRNA knockdown of either Smad2 or Smad3 blocked Ang II-induced expression of Kv1.5 and SAP97. These data suggest that AT1 receptor/TGF-ß1/P-Smad2/3 and ERK 1/2 signalings are involved in Ang II-induced Kv1.5 and SAP97 expression. Flow cytometry and Western blotting revealed that losartan and the anti-TGF-ß1 antibody diminished Ang II-induced reactive oxygen species (ROS) generation and that the antioxidants diphenyleneiodonium and N-acetyl cysteine inhibited Ang II-induced expression of P-Smad2/3, phosphorylated ERK (P-ERK) 1/2, Kv1.5, SAP97, suggesting that ROS participate in Kv1.5 and SAP97 regulation by modulating Ang II-induced P-Smad2/3 and P-ERK 1/2 expression. In conclusion, we demonstrate that ROS-dependent Ang II/AT1 receptor/TGF-ß1/P-Smad2/3 and Ang II/ERK 1/2 signalings are involved in atrial Kv1.5 and SAP97 expression. Antioxidants would be beneficial for AF treatment through inhibiting atrial Kv1.5 expression.