Honokiol ameliorates angiotensin II-induced cardiac hypertrophy by promoting dissociation of the Nur77-LKB1 complex and activating the AMPK pathway.

Pathological cardiac hypertrophy is a key contributor to heart failure, and the molecular mechanisms underlying honokiol (HNK)-mediated cardioprotection against this condition remain worth further exploring. This study aims to investigate the effect of HNK on angiotensin II (Ang II)-induced myocardial hypertrophy and elucidate the underlying mechanisms. Sprague-Dawley rats were exposed to Ang II infusion, followed by HNK or vehicle treatment for 4 weeks. Our results showed that HNK treatment protected against Ang II-induced myocardial hypertrophy, fibrosis and dysfunction in vivo and inhibited Ang II-induced hypertrophy in neonatal rat ventricular myocytes in vitro. Mechanistically, HNK suppressed the Ang II-induced Nur77 expression at the transcriptional level and promoted ubiquitination-mediated degradation of Nur77, leading to dissociation of the Nur77-LKB1 complex. This facilitated the translocation of LKB1 into the cytoplasm and activated the LKB1-AMPK pathway. Our findings suggest that HNK attenuates pathological remodelling and cardiac dysfunction induced by Ang II by promoting dissociation of the Nur77-LKB1 complex and subsequent activation of AMPK signalling. This study uncovers a novel role of HNK on the LKB1-AMPK pathway to protect against cardiac hypertrophy.

Spinosin inhibits activated hepatic stellate cell to attenuate liver fibrosis by targeting Nur77/ASK1/p38 MAPK signaling pathway.

AIM: Liver fibrosis remains a great challenge in the world. Spinosin (SPI), a natural flavonoid-C-glycoside, possesses various pharmacological activities including anti-inflammatory and anti-myocardial fibrosis effects. In this study, we investigate whether SPI can be a potential lead for the treatment of liver fibrosis and explore whether the orphan nuclear receptor Nur77, a negative regulator of liver fibrosis development, plays a critical role in SPI's action. METHODS: A dual luciferase reporter system of α-SMA was established to evaluate the effect of SPI on hepatic stellate cell (HSC) activation in LX2 and HSC-T6 cells. A mouse model of CCl4-induced liver fibrosis was used to test the efficacy of SPI against liver fibrosis. The expression levels of Nur77, inflammatory cytokines and collagen were determined by Western blotting and qPCR. Potential kinase pathways involved were also analyzed. The affinity of Nur77 with SPI was documented by fluorescence titration. RESULTS: SPI can strongly suppress TGF-ß1-mediated activation of both LX2 and HSC-T6 cells in a dose-dependent manner. SPI increases the expression of Nur77 and reduces TGF-ß1-mediated phosphorylation levels of ASK1 and p38 MAPK, which can be reversed by knocking out of Nur77. SPI strongly inhibits collagen deposition (COLA1) and reduces inflammatory cytokines (IL-6 and IL-1ß), which is followed by improved liver function in the CCl4-induced mouse model. SPI can directly bind to R515 and R563 in the Nur77-LBD pocket with a Kd of 2.14 µM. CONCLUSION: Spinosin is the major pharmacological active component of Ziziphus jujuba Mill. var. spinosa which has been frequently prescribed in traditional Chinese medicine. We demonstrate here for the first time that spinosin is a new therapeutic lead for treatment of liver fibrosis by targeting Nur77 and blocking the ASK1/p38 MAPK signaling pathway.

High serum lactate dehydrogenase as a predictor of cardiac insufficiency at follow-up in elderly patients with acute myocardial infarction.

BACKGROUND: Impairment of cardiac function progresses after acute myocardial infarction (AMI). Lactate dehydrogenase (LDH), a marker of cardiac injury and an enzyme in anaerobic glycolysis, is suggested as a risk factor for patient mortality in inflammatory diseases. METHODS: In this study, 448 older and 445 younger AMI patients were recruited and followed up. The effect of baseline serum LDH on post-infarction cardiac function was assessed at follow-up. RESULTS: Elderly patients in the high baseline LDH group had a high risk of being diagnosed with cardiac insufficiency during follow-up (adjusted hazard ratio: 3.643, P = 0.007), and the follow-up left ventricular ejection fraction of the quartile subgroup tended to decrease with increasing in baseline serum LDH (adjusted odds ratio: 1.301, P = 0.001) for each 100 U/L increase. The LVDd and LVVd of elderly patients in the high LDH group were not significantly different from those of patients in the normal LDH group at baseline but were further increased in the high LDH group at follow-up. In younger patients, the effect of LDH on post-infarction cardiac structure and function was similar to that in older patients, but unlike older patients, Cox regression analysis showed that LDH was not the predominant influence. CONCLUSION: Longitudinal changes in cardiac function were independently associated with high baseline serum LDH levels in patients with AMI. Baseline LDH levels are superior to other myocardial injury markers and may be a useful parameter in predicting future cardiac dysfunction after AMI, especially in the elderly.

Activation of AHR by ITE improves cardiac remodelling and function in rats after myocardial infarction.

AIMS: Left ventricular remodelling subsequent to myocardial infarction (MI) constitutes a pivotal underlying cause of heart failure. Intervention with the nontoxic endogenous aryl hydrocarbon receptor (AHR) agonist 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) in the acute phase of MI has been shown to ameliorate cardiac function, but its role in the chronic phase remains obscured. This study explores the beneficial role of ITE in delaying the progression of heart failure in the chronic phase of MI. METHODS AND RESULTS: MI rats established by ligating the left anterior descending coronary artery were treated with the indicated concentration of the AHR agonist ITE or vehicle alone. Echocardiography was performed to determine cardiac structure and function; myocardial morphology and fibrosis were observed by haematoxylin and eosin and Masson's trichrome staining; serum biochemical indices, BNP, and inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay; F4/80+ iNOS+ M1 macrophages and F4/80+ CD206+ M2 macrophages were detected by immunofluorescence; the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay was used to detect the apoptosis of cardiomyocytes; ultrastructural changes in myocardial tissue were observed by transmission electron microscopy; and Cyp1a1, Akt, P-Akt, p70S6K, P-p70S6K, Bcl-2, Bax, caspase-3, and cleaved caspase-3 protein levels were determined via Western blotting. We found that therapy with the AHR agonist ITE rescued cardiac remodelling and dysfunction in rats with MI and attenuated myocardial fibrosis, inflammation, and mitochondrial damage. Further studies confirmed that ITE dose-dependently improved myocardial cell apoptosis after MI, as demonstrated by reduced levels of the apoptosis-related proteins cleaved caspase-3 and Bax but increased expression levels of Bcl-2. These effects were attributed to ITE-induced activation of AHR receptors, leading to the down-regulation of Akt and p70S6K phosphorylation. CONCLUSIONS: The AHR agonist ITE alleviates cardiomyocyte apoptosis through the Akt/p70S6K signalling pathway, thereby rescuing left ventricular adverse remodelling and cardiac dysfunction after MI.

Retinoid X receptor agonists alleviate fibroblast activation and post-infarction cardiac remodeling via inhibition of TGF-ß1/Smad pathway.

Retinoid X receptor (RXR), particularly RXRα, has been implicated in cardiovascular diseases. However, the functional role of RXR activation in myocardial infarction (MI) remains unclear. This study aimed to determine the effects of RXR agonists on MI and to dissect the underlying mechanisms. Sprague-Dawley (SD) rats were subjected to MI and then treated (once daily for 4 weeks) with either RXR agonist bexarotene (10 or 30 mg/kg body weight) or vehicle. Heart function was determined using echocardiography and cardiac hemodynamic measurements. Four weeks post MI, myocardial tissues were collected to evaluate cardiac remodeling. Primary cardiac fibroblasts (CFs) were treated with or without RXR ligand 9-cis-RA followed by stimulation with TGF-ß1. Immunoblot, immunofluorescence, and co-immunoprecipitation were performed to elucidate the regulatory role of RXR agonists in TGF-ß1/Smad signaling. In vivo treatment with Bexarotene moderately affects systemic inflammation and apoptosis and ameliorated left ventricular dysfunction after MI in rat model. In contrast, bexarotene significantly inhibited post-MI myocardial fibrosis. Immunoblot analysis of heart tissue homogenates from MI rats revealed that bexarotene regulated the activation of the TGF-ß1/Smad signaling pathway. In vitro, 9-cis-RA inhibited the TGF-ß1-induced proliferation and collagen production of CFs. Importantly, upon activation by 9-cis-RA, RXRα interacted with p-Smad2 in cytoplasm, inhibiting the TGF-ß1-induced nuclear translocation of p-Smad2, thereby negatively regulating TGF-ß1/Smad signaling and attenuating the fibrotic response of CFs. These findings suggest that RXR agonists ameliorate post-infarction myocardial fibrosis, maladaptive remodeling, and heart dysfunction via attenuation of fibrotic response in CFs through inhibition of the TGF-ß1/Smad pathway activation.

The underlying mechanism of transcription factor IRF1, PRDM1, and ZNF263 involved in the regulation of NPPB rs3753581 on pulse pressure hypertension.

To investigate the correlation between NPPB gene variants and pulse pressure hypertension and the underlying regulatory mechanisms and try to confirm that NPPB may be a potential molecular target of gene therapy for pulse pressure hypertension. A total of 898 participants were recruited from the First Affiliated Hospital of Fujian Medical University and the plasmids with differential expression of NPPB were constructed. Genotype distribution of NPPB(rs3753581, rs198388, and rs198389)was analyzed and the expression of N-terminal pro-B-type natriuretic peptide(NT-proBNP) and renin-angiotensin -aldosterone system(RAAS) related indicators were identified in the groups studied. According to a genotype analysis, there was a significant difference in the genotype distribution of NPPB rs3753581 among the groups (P = 0.034). In logistic regression analysis, NPPB rs3753581 TT was associated with a 1.8-fold greater risk of pulse pressure hypertension than NPPB rs3753581 GG (odds ratio = 1.801; 95% confidence interval: 1.070-3.032; P = 0.027). The expression of NT-proBNP and RAAS related indicators in clinical and laboratory samples showed striking differences. The activity of firefly and Renilla luciferase in pGL-3-NPPB-luc (-1299G) was higher than pGL-3-NPPBmut-luc(-1299 T)(P < 0.05). The binding of NPPB gene promoter rs3753581 (-1299G) with transcription factors IRF1, PRDM1, and ZNF263 was predicted and validated by the bioinformatics software TESS and chromatin immunoprecipitation(P < 0.05). NPPB rs3753581 was correlated with genetic susceptibility to pulse pressure hypertension and the transcription factors IRF1, PRDM1, and ZNF263 may be involved in the regulation of NPPB rs3753581 promoter (-1299G) on the expression of NT-proBNP/RAAS.

Risk of cardiac-related death in astrocytoma patients treated with chemotherapy: A competing risk analysis using the SEER database.

Purpose: To explore the impact of chemotherapy on the risk of cardiac-related death in astrocytoma patients. Methods: We retrospectively evaluated astrocytoma patients diagnosed between 1,975 and 2016 in the Surveillance, Epidemiology, and End Results (SEER) database. Using Cox proportional hazards models, we compared the risks of cardiac-related death between a chemotherapy group and non-chemotherapy group. Competing-risks regression analyses were used to evaluate the difference in cardiac-related death. Also, propensity score matching (PSM) was employed to reduce confounding bias. The robustness of these findings was evaluated by sensitivity analysis, and E values were calculated. Results: A total of 14,834 patients diagnosed with astrocytoma were included. Chemotherapy (HR = 0.625, 95%CI: 0.444-0.881) was associated with cardiac-related death in univariate Cox regression analysis. Chemotherapy was an independent prognostic factor for a lower risk of cardiac-related death before (HR = 0.579, 95%CI: 0.409-0.82, P = 0.002) and after PSM (HR = 0.550, 95%CI: 0.367-0.823 P = 0.004). Sensitivity analysis determined that the E-value of chemotherapy was 2.848 and 3.038 before and after PSM. Conclusions: Chemotherapy did not increase the risk of cardiac-related death in astrocytoma patients. This study highlights that cardio-oncology teams should provide comprehensive care and long-term monitoring for cancer patients, especially those with an increased risk of cardiovascular disease.

Cardiovascular outcomes of ß-blocker-calcium channel blocker initial dual therapy vs. other initial dual therapies in Chinese patients with hypertension: A real-world retrospective study.

This retrospective study compared cardiovascular (CV) outcomes between initial ß-blocker (BB) + calcium channel blocker (CCB) dual therapy ("B + C") and other initial dual therapies in Chinese newly diagnosed hypertensive patients. In this study, all patients in a regional electronic database with newly diagnosed hypertension from January 01, 2012 to December 31, 2016 who received any initial optimal dual therapy recommended by the Chinese hypertension guideline were included. 1:2 propensity score matching (PSM) was used to balance baseline characteristics between patients receiving B + C and patients receiving other initial dual therapies ("Others"). The primary outcome was major adverse cardiovascular events (MACE) that occurred from January 01, 2012 to December 31, 2017, consisting of non-fatal stroke, non-fatal myocardial infarction (MI), non-fatal chronic heart failure (CHF), and all-cause death. Cox proportional hazard models were used to compare these CV outcomes in the 2 matched cohorts. After the PSM, 6227 patients receiving B + C and 12 454 patients receiving Others were included. Compared to patients receiving Others, patients receiving B + C had a significantly lower risk of MACE (hazard ratio [HR] 0.85; 95% confidential interval [CI] 0.78-0.92; p < .001), non-fatal stroke (HR 0.89; 95% CI 0.81-0.98; p = .018) and non-fatal CHF (HR 0.74; 95% CI 0.63-0.86; p < .0001). Additionally, differences in risks of non-fatal MI and all-cause death between the 2 treatment cohorts were not statistically significant. In conclusion, BB + CCB initial dual therapy was associated with a lower risk of MACE, stroke, and CHF than other optimal initial dual therapies recommended by the Chinese hypertension guideline in Chinese newly diagnosed hypertensive patients.

Dapagliflozin: a sodium-glucose cotransporter 2 inhibitor, attenuates angiotensin II-induced cardiac fibrotic remodeling by regulating TGFß1/Smad signaling.

BACKGROUND: Cardiac remodeling is one of the major risk factors for heart failure. In patients with type 2 diabetes, sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of the first hospitalization for heart failure, possibly through glucose-independent mechanisms in part, but the underlying mechanisms remain largely unknown. This study aimed to shed light on the efficacy of dapagliflozin in reducing cardiac remodeling and potential mechanisms. METHODS: Sprague-Dawley (SD) rats, induced by chronic infusion of Angiotensin II (Ang II) at a dose of 520 ng/kg per minute for 4 weeks with ALZET® mini-osmotic pumps, were treated with either SGLT2 inhibitor dapagliflozin (DAPA) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Cardiac fibroblasts (CFs) were treated with Ang II (1 µM) with or without the indicated concentration (0.5, 1, 10 µM) of DAPA. The protein levels of collagen and TGF-ß1/Smad signaling were measured along with body weight, and blood biochemical indexes. RESULTS: DAPA pretreatment resulted in the amelioration of left ventricular dysfunction in Ang II-infused SD rats without affecting blood glucose and blood pressure. Myocardial hypertrophy, fibrosis and increased collagen synthesis caused by Ang II infusion were significantly inhibited by DAPA pretreatment. In vitro, DAPA inhibit the Ang II-induced collagen production of CFs. Immunoblot with heart tissue homogenates from chronic Ang II-infused rats revealed that DAPA inhibited the activation of TGF-ß1/Smads signaling. CONCLUSION: DAPA ameliorates Ang II-induced cardiac remodeling by regulating the TGF-ß1/Smad signaling in a non-glucose-lowering dependent manner.

Anti-Diabetic Atherosclerosis by Inhibiting High Glucose-Induced Vascular Smooth Muscle Cell Proliferation via Pin1/BRD4 Pathway.

METHODS: Diabetic Apoe-/- mice induced by streptozotocin were treated with vehicle, the Pin1 inhibitor juglone, or the BRD4 inhibitor JQ1 for 3 weeks. VSMCs were pretreated with juglone, JQ1, or vehicle for 45 min, and then exposed to high glucose for 48 h. Hematoxylin-eosin staining was performed to assess atherosclerotic plaques of the thoracic aorta. Western blotting was used to detect expression levels of Pin1, BRD4, cyclin D1, and matrix metalloproteinase-9 (MMP-9) in the thoracic aorta and VSMCs. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assay were used to measure proliferation and migration of VSMCs. RESULTS: Juglone and JQ1 significantly improved atherosclerosis of diabetic Apoe-/- mice and reduced high glucose-induced VSMC proliferation and migration. Cyclin D1 and MMP-9 levels in the thoracic aorta were lower in diabetic Apoe-/- mice treated with juglone and JQ1 compared with vehicle-treated diabetic Apoe-/- mice. Additionally, BRD4 protein expression in high glucose-induced VSMCs was inhibited by juglone and JQ1. Upregulation of Pin1 expression by transduction of the Pin1 plasmid vector promoted BRD4 expression induced by high glucose, and stimulated proliferation and migration of VSMCs. CONCLUSIONS: Inhibition of Pin1/BRD4 pathway may improve diabetic atherosclerosis by inhibiting proliferation and migration of VSMCs.

Retinoid X receptor agonists attenuates cardiomyopathy in streptozotocin-induced type 1 diabetes through LKB1-dependent anti-fibrosis effects.

Diabetic cardiac fibrosis increases ventricular stiffness and facilitates the occurrence of diastolic dysfunction. Retinoid X receptor (RXR) plays an important role in cardiac development and has been implicated in cardiovascular diseases. In the present study, we investigated the effects of RXR agonist treatment on streptozotocin (STZ)-induced diabetic cardiomyopathy (DCM) and the underlying mechanism. Sprague-Dawley (SD) rats induced by STZ injection were treated with either RXR agonist bexarotene (Bex) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Cardiac fibroblasts (CFs) were treated with high glucose (HG) with or without the indicated concentration of Bex or the RXR ligand 9-cis-retinoic acid (9-cis-RA). The protein abundance levels were measured along with collagen, body weight (BW), blood biochemical indexes and transforming growth factor-ß (TGF-ß) levels. The effects of RXRα down-regulation by RXRα small interfering RNA (siRNA) were examined. The results showed that bexarotene treatment resulted in amelioration of left ventricular dysfunction by inhibiting cardiomyocyte apoptosis and myocardial fibrosis. Immunoblot with heart tissue homogenates from diabetic rats revealed that bexarotene activated liver kinase B1 (LKB1) signaling and inhibited p70 ribosomal protein S6 kinase (p70S6K). The increased collagen levels in the heart tissues of DCM rats were reduced by bexarotene treatment. Treatment of CFs with HG resulted in significantly reduced LKB1 activity and increased p70S6K activity. RXRα mediated the antagonism of 9-cis-RA on HG-induced LKB1/p70S6K activation changes in vitro. Our findings suggest that RXR agonist ameliorates STZ-induced DCM by inhibiting myocardial fibrosis via modulation of the LKB1/p70S6K signaling pathway. RXR agonists may serve as novel therapeutic agents for the treatment of DCM.

VDR Agonist Prevents Diabetic Endothelial Dysfunction through Inhibition of Prolyl Isomerase-1-Mediated Mitochondrial Oxidative Stress and Inflammation.

BACKGROUND AND AIM: Upregulation of prolyl isomerase-1 (Pin1) protein expression and activity was associated with the pathogenesis of diabetic vasculopathy through induction of endothelial oxidative stress and inflammation. Moreover, VDR agonist protects against high glucose-induced endothelial apoptosis through the inhibition of oxidative stress. We aimed to explore the effects of the VDR agonist on diabetes-associated endothelial dysfunction and the role of Pin1 in this process. METHODS: Streptozocin-induced diabetic mice were randomly treated with vehicle, VDR agonist (10 µg/kg/d, i.g., twice a week), or Pin1 inhibitor, Juglone (1 mg/kg/d, i.p., every other day), for eight weeks. In parallel, human umbilical vein endothelial cells (HUVECs) exposed to high-glucose condition were treated with 1,25-dihydroxyvitamin D3 and Juglone or vehicle for 72 hours. Organ chamber experiments were performed to assess endothelium-dependent relaxation to acetylcholine. Circulatory levels of Pin1, SOD, MDA, IL-1ß, IL-6, and NO in diabetic mice, Pin1 protein expression and activity, subcellular distribution of p66Shc, and NF-κB p65 in high glucose-cultured HUVECs were determined. RESULTS: Both VDR agonist and Juglone significantly improved diabetes-associated endothelial dysfunction and reduced high glucose-induced endothelial apoptosis. Mechanistically, the circulatory levels of SOD and NO were increased compared with those of vehicle-treated diabetic mice. Additionally, Pin1 protein expression and activity, p66Shc mitochondrial translocation, and NF-κB p65 in high glucose-cultured HUVECs were also inhibited by VDR agonist and Juglone. Knockdown of VDR abolished the inhibitory effects of VDR agonist on high glucose-induced upregulation of Pin1 protein expression and activity. CONCLUSIONS: VDR agonist prevents diabetic endothelial dysfunction through inhibition of Pin1-mediated mitochondrial oxidative stress and inflammation.

[Effects and related mechanism of retinoid X receptor agonist bexarotene on atherosclerosis progression in diabetic apoE(-/-) mice].

OBJECTIVE: To explore the effect of retinoid X receptor (RXR) agonist bexarotene on atherosclerosis and the potential mechanism in streptozotocin (STZ) induced diabetic apolipoprotein E knockout (apoE(-/-)) mice. METHODS: Eight C57BL/6 mice served as control, 46 apoE(-/-) mice were randomized into 4 groups: apoE(-/-) group (n = 10), STZ+apoE(-/-) group (n = 12), STZ+apoE(-/-)+Bex 10 (10 mg×kg⁻¹×d⁻¹)group (n = 12), STZ+ apoE(-/-)+Bex 30 (30 mg×kg⁻¹×d⁻¹) group (n = 12). Diabetic apoE(-/-) animal model was established by intraperitoneal injection of STZ. Blood glucose was determined by glucose oxidase method. Patch area in thoracic aorta was measured by HE staining. Western blotting was used to determine the RXR and gp91(phox) protein level in thoracic aorta. Reactive oxygen species (ROS) level in blood and thoracic aorta homogenates was detected by Fenton and Griess method. RESULTS: (1) Patch areas of thoracic aorta were larger in apoE(-/-) group than in C57BL/6 group [(38.40 ± 8.95)µm² vs. (0.10 ± 0.01) µm², P < 0.01], further increased in STZ+apoE(-/-) group [(94.06 ± 8.04)µm², P < 0.05 vs. apoE(-/-) group] and significantly reduced in STZ+apoE(-/-)+Bex 10 group [(78.72 ± 4.62)µm², P < 0.05 vs. STZ+apoE(-/-) group] and further educed in STZ+apoE(-/-)+Bex 30 group [(46.13 ± 7.56)µm², P < 0.05 vs. STZ+apoE(-/-)+Bex 10 group]. (2) Blood glucose level, TG, TC, LDL-C, thoracic aorta gp91(phox) protein level and ROS level in blood and thoracic aorta homogenates were significantly higher in STZ+apoE(-/-) group than in apoE(-/-) group (all P < 0.05). Blood glucose level and TG, TC, LDL-C levels were similar between STZ+apoE(-/-)+Bex10 and STZ+apoE(-/-) group. Thoracic aorta gp91(phox) protein level and ROS level in blood and thoracic aorta homogenates were lower in STZ+apoE(-/-)+Bex 10 group than in STZ+apoE(-/-) group (P < 0.05). Blood glucose level, TG, TC, LDL-C levels, gp91(phox) expression in thoracic aorta, ROS level in blood and thoracic in STZ+apoE(-/-)+Bex 30 group were lower than in STZ+apoE(-/-) group (all P < 0.05). CONCLUSION: Bexarotene treatment could attenuate arteriosclerosis progression in STZ induced diabetic apoE(-/-) mice, the underlying mechanism might be related to suppressing oxidative stress and decreasing blood glucose level and improving lipids metabolism.

Retinoid X receptor agonists inhibit hypertension-induced myocardial hypertrophy by modulating LKB1/AMPK/p70S6K signaling pathway.

BACKGROUND: Retinoid X receptor (RXR) has been demonstrated to play an important role in cardiac development and has been implicated in cardiovascular diseases. This study aimed to examine the effects of RXRα agonist bexarotene on pathological left ventricular hypertrophy (LVH) in a spontaneously hypertensive rat (SHR) model and the underlying mechanism. METHODS: WKY rats served as controls. SHRs were randomized into 3 groups at the age of 4 weeks and were treated (once daily for 12 weeks) with either bexarotene (30 or 100mg/kg body weight) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Neonatal cardiomyocytes were treated with AngII (10(-7) mmol/L) with or without the indicated concentration of RXRα ligand 9-cis-RA. The protein abundances of ß-actin, RXRα, LKB1, phospho-LKB1, AMPK, phospho-AMPK, P70S6K, phospho-P70S6K, ACE, and AT1 receptor were measured along with blood pressure, body weight and angiotensin II (Ang II) levels. The effects of LKB1 downregulation by LKB1 small, interfering RNA were examined. RESULTS: Treatment of SHRs with bexarotene resulted in significant inhibition of LVH without eliminating hypertension. Immunoblot with heart tissue homogenates from SHRs revealed that bexarotene activated the LKB1/AMPK signaling pathway and inhibited p70S6K. However, the increased Ang II levels in SHR serum and heart tissue were not reduced by bexarotene treatment. Treatment of cardiomyocytes with Ang II resulted in significantly reduced LKB1/AMPK activity and increased p70S6K activity. 9-cis-RA antagonized Ang II-induced LKB1/AMPK and p70S6K activation changes in vitro. CONCLUSIONS: RXR agonists prevent the inhibition of the LKB1/AMPK/p70S6K pathway and regulate protein synthesis to reduce LVH. This antihypertrophic effect of bexarotene is independent of blood pressure.

Metformin reduces vascular endothelial dysfunction caused by an acute glucose load in patients with hypertension.

BACKGROUND: To investigate the effects of a single dose of metformin (MF) on endothelium-dependent vasodilatation and serum antioxidant and free fatty acid levels in patients with primary hypertension (PH) after an acute glucose load. MATERIALS AND METHODS: Patients with untreated PH were randomized to a no-metformin group (PH, n = 34) and a metformin group (PH+ MF, n = 28) who received a single dose of 500 mg metformin before testing. Healthy volunteers (n = 31) served as a control group. Brachial artery endothelium-dependent flow-mediated vasodilatation (FMD) was determined at 0, 1, 2 and 3 h after glucose load. Levels of serum superoxide dismutase (SOD), total antioxidant capacity (T-AOC), anti-superoxide anion free radical (AntiO2) and free fatty acids (FFA) were measured. RESULTS: The FMD in the PH group decreased significantly 1 h after glucose load (PH: 10.9 ± 2.9% vs 13.67 ± 3.42% before glucose load). Metformin inhibited the effects of glucose load on FMD. At 1 h after acute glucose load, the concentrations of SOD, T-AOC and AntiO2 in the PH group decreased significantly compared with their fasting levels, and metformin inhibited the acute glucose load-induced decline in SOD and T-AOC levels. CONCLUSIONS: Metformin can prevent transient endothelial dysfunction caused by acute glucose load in patients with PH.

Effects of combined glucose and fat load on endothelium-dependent brachial artery vasodilatation in hypertensive patients.

INTRODUCTION: This study investigated the effects of combined glucose and fat load on glucose and lipid metabolism, as well as on vascular endothelial function, in hypertensive patients. METHODS AND RESULTS: A total of 98 hypertensive patients were randomly divided into 3 groups that received an oral fat tolerance test (OFTT), an oral glucose tolerance test (OGTT) or a combined oral glucose and fat tolerance test (OGFTT). Endothelium-dependent flow-mediated brachial artery dilation (FMD) was measured by vascular ultrasound and was used as an indicator of vascular endothelial function. There were no significant differences in demographics or clinical characteristics among the 3 groups before the study. Immediately after the OGFTT, the serum triglyceride levels and the area under the curve for serum glucose in the OGFTT group were not significantly different from those in the other 2 groups. However, the 1-hour FMD in the OGFTT group was significantly reduced compared with that of the OGTT group (5.45 ± 0.75 versus 9.46 ± 1.32, P < 0.05), and the 4-hour FMD in the OGFTT group was also significantly reduced compared with the OFTT group (8.56 ± 1.09 versus 9.76 ± 2.00, P < 0.05). CONCLUSION: A combined glucose and fat load has a cumulative effect on vascular endothelial dysfunction in hypertensive patients.

[Association between high sensitivity C-reactive protein and contrast induced acute kidney injury in patients with acute coronary syndrome undergoing percutaneous coronary intervention: impact of atorvastatin].

OBJECTIVE: To observe the association between preprocedural high sensitivity C-reactive protein (hs-CRP) level and incidence of contrast induced acute kidney injury (CI-AKI) in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) and the impact of atorvastatin pretreatment on CI-AKI. METHODS: According to the level of preprocedural hs-CRP, 270 ACS patients were divided into three groups: high hs-CRP group (hs-CRP ≥ 3 mg/L, n = 176), moderate hs-CRP group (hs-CRP 1-3 mg/L, n = 60) and normal hs-CRP group (hs-CRP < 1 mg/L, n = 34). According to the dosage of preprocedural atorvastatin, the high hs-CRP group was further divided into 10 mg group (n = 49), 20 mg group (n = 66) and 40 mg group (n = 61). Serum creatinine (Scr), blood urea nitrogen (BUN), cystatin C (Cys C), hs-CRP were measured at before and 24 hours, 48 hours after PCI. CCr and GFR were calculated according to Scr and Cys C. Risk factors for CI-AKI were determined by multivariate logistic regression analysis. RESULTS: (1) Cys C was significantly increased and GFR after PCI significantly reduced in high and moderate hs-CRP groups compared with normal hs-CRP group (P < 0.05). (2) Incidence of CI-AKI was 43.18%, 38.33%, 20.59% in high, moderate and normal hs-CRP groups, respectively (P < 0.05). (3) In high hs-CRP group, postprocedural GFR was significantly higher while postprocedural Cys C and hs-CRP were significantly lower in 40 mg statin subgroup than 10 mg and 20 mg statin subgroups (P < 0.05), similar trends were documented when comparing 20 mg statin subgroup with 10 mg statin subgroup (P < 0.05). (4) Multivariate logistic regression analysis showed that pretreatment with high dose atorvastatin was a protective factor for post CI-AKI (20 mg atorvastatin: OR = 0.15, 95%CI 0.06 - 0.33, P = 0.001; 40 mg atorvastatin: OR = 0.10, 95%CI 0.04 - 0.23, P = 0.001), while high levels of preprocedural hs-CRP (OR = 2.06, 95%CI 1.01 - 4.23, P = 0.048), diabetes mellitus (OR = 10.71, 95%CI 5.29 - 21.70, P = 0.001), advanced age (OR = 2.64, 95%CI 1.05 - 6.63, P = 0.038) and renal failure (OR = 5.14, 95%CI 1.13 - 23.39, P = 0.034) were independent risk factors of CI-AKI. CONCLUSION: High hs-CRP level is linked with the development of CI-AKI in ACS patients undergoing PCI and pretreatment with 40 mg atorvastatin is associated with lower incidence CI-AKI, possibly by reducing the postprocedural inflammation responses.

[Impact of acute glucose and fat loading on endothelium dependent vasodilation in patients with essential hypertension].

OBJECTIVE: To explore the influence of acute glucose and fat loading on endothelium dependent flow-mediated vasodilation (FMD) in patients with essential hypertension (EH). METHODS: Patients with EH were randomly divided into three groups: oral glucose loading alone (n = 26), oral standardized fat loading alone (n = 38), combined glucose and fat loading (n = 34). FMD of the brachial artery was assessed by high resolution ultrasound technique respectively. RESULTS: (1) Compared to control group, postprandial abnormal serum triglyceride metabolism was evidenced and FMD was significantly reduced and the lowest FMD occurred at 4 hours and returned to the baseline level at 8 hours post fat loading alone in EH patients. (2) GS-AUC and 1 hour glucose were significantly higher in EH patients than in controls (all P < 0.05), FMD was also significant decreased (-31.4%) at 1 hour and returned to baseline level at 2 hours post oral glucose loading. (3) After combined glucose and fat loading, FMD at 1 hour (5.45 ± 1.93 vs. 9.46 ± 3.33, P < 0.05) was significantly lower than that in glucose loading alone and FMD at 4 hours (7.98 ± 1.64 vs. 9.66 ± 2.26, P < 0.05), was also lower than that in fat loading alone in EH patients. (4) FMD was negatively correlated with SBP, GS-AUC, DBP, TG-AUC (γ = -0.46, -0.44, -0.41, -0.38, respectively, all P < 0.05). CONCLUSION: Combined glucose and fat loading additively reduced FMD in hypertensive patients.

Retinoid X receptor agonists inhibit phorbol-12-myristate-13-acetate (PMA)-induced differentiation of monocytic THP-1 cells into macrophages.

Monocyte/macrophage differentiation is an essential process during atherosclerosis development. The retinoid X receptor (RXR) is a member of the nuclear hormone receptor superfamily, which plays an important regulatory role in many metabolic disorders, including atherosclerosis. The purpose of this study was to investigate the effect of RXR agonist on monocyte/macrophage differentiation in vitro. The THP-1 cell line was differentiated into a macrophage-like phenotype by incubation with phorbol-12-myristate-13-acetate (PMA) in the presence or absence of RXR agonist. The viability of adherent differentiated THP-1 cells was determined by MTT assay. Macrophage surface marker CD11b and CD36 was analyzed by flow cytometry. Phagocytosis was measured by fluorescence-labeled latex beads. The production of Cytokine Tunlornecrosisfactor-alpha (TNF-alpha), Interlaken-12p70 (IL-12p70), and Matrix metalloproteinase-9 (MMP-9), each of which was analyzed by ELISA. In the presence of the RXR agonists 9-cis retinoic acid or SR11237, PMA-induced THP-1 cells became less adherent, showed decreased macrophage-like morphological changes, decreased cell surface antigen CD11b and CD36 expression, and down regulated the phagocytosis of latex beads and the production of TNF-alpha and MMP-9. These data suggest that RXR agonists inhibit PMA-induced THP-1 cell differentiation into macrophage-like cells, which may be helpful in understanding the anti-atherosclerotic effect of RXR and its agonists.

RXR agonists inhibit oxidative stress-induced apoptosis in H9c2 rat ventricular cells.

Retinoid X receptor (RXR) plays a central role in the regulation of intracellular receptor signaling pathways. We examined its role in regulating oxidative stress-induced apoptosis in H9c2 rat ventricular cells. We showed for the first time that functional RXR protein was downregulated by hydrogen peroxide (H2O2) in H9c2 cardiomyocytes. Natural and synthetic agonists of RXR, 9-cis-RA, and LGD1069 respectively, prevented H2O2-triggered apoptosis, and this anti-apoptotic effect was inhibited by the RXR antagonist HX531. Further investigation into the protective mechanisms of RXR demonstrated that H2O2-induced loss of mitochondrial membrane potential, mitochondrial release of cytochrome c and caspase-3 activation were all significantly attenuated by pretreatment with RXR agonists. Furthermore, this protection was associated with a reduction in intracellular reactive oxygen species and an upregulation in catalase activity. Thus, these data indicate that pharmacological activation of RXR exerts protective effects against H2O2-induced apoptosis in H9c2 rat ventricular cells through antioxidant and mitochondria-protective mechanisms.