The Release of Cyclophilin A from Rapamycin-Stimulated Vascular Smooth Muscle Cells Mediated by Myosin II Activation: Involvement of Apoptosis but Not Autophagy.

INTRODUCTION: The exocytosis of cyclophilin A (CyPA) by a vesicular pathway in response to reactive oxygen species has been determined. However, other sources of extracellular CyPA remain obscure. OBJECTIVE: The aim of this study was to determine the role of autophagy in the secretion of CyPA. METHODS AND RESULTS: Rapamycin induced the activation of autophagy and release of CyPA from primary cultured rat aortic smooth muscle cells (RASMCs). However, inhibition of autophagy by knockdown of Atg7 or chloroquine did not affect the rapamycin-induced release of CyPA. With the exception of myosin II activity, rho-associated coiled-coil kinase (ROCK), actin remodelling, and synaptic vesicles were not implicated in the release of rapamycin-induced CyPA. Finally, we confirmed that rapamycin-induced extracellular CyPA originated from apoptotic RASMCs. Furthermore, the decreased activation of myosin II by blebbistatin blocked the release of CyPA from apoptotic RASMCs induced by rapamycin. CONCLUSIONS: Rapamycin induced the release of CyPA from apoptotic RASMCs but did not affect exocytosis through autophagosomes. ROCK, actin remodelling, and synaptic vesicles were not involved in the apoptosis-related release of CyPA. Myosin II activation modulated the apoptosis of vascular smooth muscle cells and the release of CyPA from rapamycin-induced apoptotic cell death.

A Low-Normal Free Triiodothyronine Level Is Associated with Adverse Prognosis in Euthyroid Patients with Heart Failure Receiving Cardiac Resynchronization Therapy.

Thyroid dysfunction is prevalent in patients with heart failure (HF) and hypothyroidism is related to the adverse prognosis of HF subjects receiving cardiac resynchronization therapy (CRT). We aim to investigate whether low-normal free triiodothyronine (fT3) level is related to CRT response and the prognosis of euthyroid patients with HF after CRT implantation.One hundred and thirteen euthyroid patients who received CRT therapy without previous thyroid disease and any treatment affecting thyroid hormones were enrolled. All of patients were evaluated for cardiac function and thyroid hormones (serum levels of fT3, free thyroxine [fT4] and thyroid-stimulating hormone [TSH]). The end points were overall mortality and hospitalization for HF worsening. During a follow-up period of 39 ± 3 weeks, 36 patients (31.9%) died and 45 patients (39.8%) had hospitalization for HF exacerbation. A higher rate of NYHA III/IV class and a lower fT3 level were both observed in death group and HF event group. Multivariate Cox regression analyses disclosed that a lower-normal fT3 level (HR = 0.648, P = 0.009) and CRT response (HR = 0.441, P = 0.001) were both independent predictors of overall mortality. In addition, they were also both related to HF re-hospitalization event (P < 0.01 for both). Patients with fT3 < 3.00 pmol/L had a significantly higher overall mortality than those with fT3 ≥ 3.00 pmol/L (P = 0.027). Meanwhile, a higher HF hospitalization event rate was also found in patients with fT3 < 3.00 pmol/L (P < 0.001).A lower-normal fT3 level is correlated with a worse cardiac function an adverse prognosis in euthyroid patients with HF after CRT implantation.

Oxidized Low-Density Lipoprotein-Induced Cyclophilin A Secretion Requires ROCK-Dependent Diphosphorylation of Myosin Light Chain.

OBJECTIVE: Accumulation of cyclophilin A (CyPA) within atherosclerotic lesions is thought to be implicated in the progression of atherosclerosis. However, the source of CyPA within atherosclerotic lesions is still unknown. The aim of this study is to determine the role of oxidized low-density lipoproteins (ox-LDL) in vascular smooth muscle cell (VSMC)-derived CyPA secretion and the underlying mechanism. METHODS AND RESULTS: Abundant CyPA and α-smooth muscle actin (α-SMA) expressed in atherosclerotic lesions was observed in apolipoprotein E-deficient mice. ox-LDL induced CyPA secretion from a primary culture of rat aortic smooth muscle cells in a dose- and time-dependent manner. Sulfosuccinimidyloleate, a CD36 inhibitor, prevented the ox-LDL-induced CyPA secretion. Pre-exposure to either the actin-depolymerizing agent cytochalasin D or the actin-polymerizing agent jasplakinolide inhibited CyPA secretion induced by ox-LDL. Gene silencing of vesicle-associated membrane protein 2 suppressed ox-LDL-induced CyPA secretion. ox-LDL caused the phosphorylation of myosin light chain (MLC). Inhibition of MLC by blebbistatin reversed the secretion of CyPA and the phosphorylation of MLC induced by ox-LDL. MLC kinase inhibitor ML-7 reduced the monophosphorylation of MLC but did not reduce CyPA secretion. Pretreatment with the rho-associated coiled-coil kinase (ROCK) inhibitor Y27632 blocked diphosphorylation of MLC and secretion of CyPA induced by ox-LDL. CONCLUSIONS: ox-LDL-induced CyPA secretion requires vesicle transportation, actin remodeling and ROCK-dependent diphosphorylation of MLC. VSMC-derived CyPA induced by ox-LDL may be associated with increased CyPA expression in atherosclerotic lesions.

Eosinophilic granulomatosis with polyangiitis presenting with repetitive acute coronary syndrome, refractory coronary vasospasm, and spontaneous coronary dissection: a case report.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of eosinophilic vasculitis that is mainly limited to small- and medium-sized arteries. Cardiac involvement is the leading cause of death in patients with EGPA. Spontaneous coronary artery dissection (SCAD) is an important cause of acute coronary syndrome in middle-aged women with no or few traditional cardiovascular risk factors. EGPA manifesting as repetitive acute coronary syndrome and SCAD has not been reported. A 45-year-old woman presented with recurrent chest pain and cardiogenic shock associated with coronary vasospasm refractory to common vasodilators. Coronary angiography showed SCAD at the proximal right coronary artery. Blood tests showed significant eosinophilia. In addition to sinusitis as shown by nasal computed tomography and abnormal nerve conduction velocity, the diagnosis of EGPA was made and immunosuppression commenced. During a 20-month follow-up, the patient remained free from symptoms and adverse cardiovascular events. EGPA can involve coronary arteries and may rarely manifest as SCAD or vasospasm. We herein review the mechanism underlying coronary involvement of EGPA and emphasize special clues for its detection. Early recognition and initiation of immunosuppression therapy are important.

Twelve-week high-fat diet for improving adverse ventricular remodeling post-myocardial infarction by alleviating local inflammation.

Background: Many studies have examined how to achieve better outcomes in myocardial infarction (MI) patients with mild obesity or who are overweight. However, the influence of a high-fat diet (HFD) and the underlying mechanisms by which it can affect ventricular remodeling following MI are poorly understood. This study investigated the impact of a 12-week HFD on the left ventricular (LV) remodeling of permanent MI models and immune cell involvement. Methods: Male C57BL/6J mice were fed HFD or normal diet (ND). After 8 weeks of feeding, mice underwent cardiac left anterior descending coronary artery ligation, and the same diet was continued for a further 4 weeks. Cardiac structure and function were detected using echocardiography. Cardiac fibrosis was evaluated using histological staining at 7 and 28 days post-MI. Infiltration of various immune cells was examined using flow cytometry and immunofluorescence at 7 days post-MI. Results: Compared with a ND, the 12-week HFD feeding significantly alleviated ventricular remodeling following MI. HFD mice showed reduced infiltration of neutrophils, a higher proportion of M2/M1 macrophages, decreased conventional and monocyte-derived dendritic cells (moDCs) in the injured myocardium, and elevated levels of regulatory T cells (Tregs). Further investigation of dendritic cells (DCs) phenotypes indicated downregulated expression of major histocompatibility complex class II (MHCII). It also showed costimulatory molecules CD40 and CD86 on conventional and moDCs in mediastinal lymph nodes (mLNs). Conclusions: This study demonstrated the protective effect of a 12-week HFD on ventricular remodeling following MI via the alleviation of local inflammation.

Oxidized low-density lipoprotein inhibits the degradation of cyclophilin A via the lysosome in vascular smooth muscle cells.

BACKGROUND: Cyclophilin A (CyPA) plays an important role in the progression of atherosclerosis. Additionally, it has been reported that lysosomal function is markedly impaired in atherosclerosis induced by oxidized low-density lipoprotein (ox-LDL). As the CyPA degradation pathway remains to be elucidated, we aimed to uncover the role of lysosomes and ox-LDL in the degradation of CyPA. METHODS: We exploited RNA interference (RNAi) in combination with either the lysosomal inhibitor chloroquine (CQ) or the proteasomal inhibitor MG-132 to examine CyPA turnover. We also investigated the role of ox-LDL in lysosomal function and the CyPA degradation pathway and determined whether CyPA interacts with the selective autophagy adaptor p62. RESULTS: CQ markedly reversed the CyPA downregulation induced by RNAi and increased intracellular levels of LC3 and p62. MG-132 significantly suppressed polyubiquitinated protein degradation but did not inhibit RNAi-induced CyPA downregulation. Additionally, neither CQ nor MG-132 influenced the gene-silencing efficiency of CyPA siRNA. Moreover, ox-LDL induced cytosolic accumulation of p62 was inconsistent with increased expression of LC3-II. Meanwhile, ox-LDL inhibited RNAi-induced downregulation of CyPA. Immunofluorescence indicated colocalization of endogenous CyPA with ubiquitin and with p62 in response to CQ treatment, and co-immunoprecipitation analysis confirmed interaction between CyPA and p62. CONCLUSION: CyPA is degraded by a lysosome-dependent pathway that may involve p62-mediated selective autophagy. Furthermore, ox-LDL modulates the degradation of CyPA via its inhibitory role in lysosomes, contributing to increased expression of CyPA in atherosclerotic plaques.

Honeycomb-like structure in the right coronary artery treated with a drug-eluting stent: a case report and literature review.

A honeycomb-like structure (HLS) is a rare entity encountered in catheterization laboratories. The etiology of HLS remains elusive. Moreover, no treatment guideline or consensus for HLS has been proposed. However, with more frequent adoption of intravascular imaging modalities, the number of cases of HLS is rising. We herein present a case of HLS and summarize previous reports in the literature with the aim of providing useful information for interventional cardiologists and promoting further research.

Effect of Endoplasmic Reticulum Stress and Autophagy in the Regulation of Post-infarct Cardiac Repair.

BACKGROUND: Acute myocardial infarction (AMI) is reported to be accompanied by endoplasmic reticulum (ER) stress and autophagy induction. Nevertheless, the roles of ER stress and autophagy in post-infarct reparative fibrosis remain to be elucidated. AIM: To investigate the effects of ER stress and autophagy on the regulation of post-infarct reparative fibrosis. METHODS: The expression of GRP78 and LC3 in cardiac fibroblasts in human heart tissues obtained from patients with or without AMI was assessed by immunofluorescence. In vitro, human cardiac fibroblasts (HCFs) were stimulated by various agents, the expression of GRP78, LC3 and fibronectin in these was evaluated by immunoblot and/or immunofluorescence. RESULTS: After AMI, HCFs expressed significantly higher levels of GRP78 and LC3. ER stress inducer, tunicamycin (200 ng/mL) significantly increased the level of autophagy and reduced expression of fibronectin in HCFs, both of which were reversed by 4 Phenylbutyric acid. Under the condition of ER stress, the expression of fibronectin in HCFs was regulated by different levels of autophagy. LC3 co-localized with fibronectin when stimulated HCFs with tunicamycin. CONCLUSION: AMI induces ER stress in cardiac fibroblasts, down-regulating fibronectin via enhanced autophagy. These findings suggest that ER stress and autophagy may be a therapeutic target to improve prognosis of patients with AMI.

Yes-associated protein mediates angiotensin II-induced vascular smooth muscle cell phenotypic modulation and hypertensive vascular remodelling.

OBJECTIVES: Yes-associated protein (YAP) has been reported to regulate cell proliferation and differentiation. We aimed to characterize the role of YAP in angiotensin II (Ang II)-induced hypertensive vascular remodelling (HVR) and vascular smooth muscle cells (VSMCs) phenotypic modulation and to explore the underlying mechanisms. MATERIALS AND METHODS: An HVR rat model was established by continuous Ang II infusion for 2 weeks. Western blotting, qRT-PCR, and confocal microscopy were conducted to assess YAP expression. YAP-shRNA interfering plasmid and adenovirus were constructed to knock down YAP. We used cell proliferation and migration assays, accompanied by pathway inhibitors, to evaluate the biological function and underlying mechanisms. RESULTS: Ang II upregulated YAP expression in the media of carotid artery; however, in vivo YAP silencing significantly mitigated HVR, independent of the blood pressure level. Ang II upregulated YAP expression and promoted YAP nuclear accumulation in a dose- and time-dependent manner in rat VSMCs. YAP knockdown ameliorated Ang II-induced VSMCs phenotypic modulation. The regulation of YAP by Ang II could be blocked by pretreatment with angiotensin receptor type 1 antagonist losartan or F-actin depolymerizing agent latrunculin B but not the AT2R antagonist PD 123319. Disrupting the YAP-TEA domain (TEAD) interaction with verteporfin inhibited Ang II-induced VSMCs phenotypic modulation. CONCLUSIONS: Yes-associated protein mediated angiotensin II-induced VSMCs phenotypic modulation and vascular remodelling. YAP is a potential therapeutic target for HVR beyond blood pressure control.

Prognostic Impact of Fasting Plasma Glucose on Mortality and Re-Hospitalization in Patients with Acute Heart Failure.

BACKGROUND: The impact of fasting plasma glucose (FPG) on survival outcomes in patients with acute heart failure (HF) is unclear, and the relationship between intensity of glycemic control of FPG in diabetes mellitus (DM) patients and HF prognosis remains uncertain. This retrospective study aimed to evaluate the prognostic impact of FPG in patients with acute HF. METHODS: A total of 624 patients hospitalized with acute HF from October 2000 to April 2014 were enrolled in this study. All patients were stratified by three groups according to their admission FPG levels (i.e., DM, impaired fasting glucose [IFG], and non-DM). All-cause and cardiovascular mortality was the primary end point, and HF re-hospitalization was the secondary end point during follow-up period. RESULTS: A total of 587 patients were included in final analysis. The all-cause mortality rates of patients with DM, IFG, and non-DM were 55.5%, 40.3%, and 39.2%, with significant difference (P = 0.001). Moreover, compared with those with IFG (34.3%) and non-DM (32.6%), patients with DM had significantly higher rate of cardiovascular mortality (45.1%). Multiple Cox regression analysis showed that DM as well as IFG was related to all-cause mortality (DM: hazard ratio [HR] = 1.936, P < 0.001; IFG: HR = 1.672, P = 0.019) and cardiovascular mortality (DM: HR = 1.739, P < 0.001; IFG: HR = 1.817, P = 0.013). However, they were both unrelated to HF re-hospitalization. DM patients with strictly controlled blood glucose (FPG <3.9 mmol/L) had higher all-cause mortality than patients with non-DM, IFG, and DM patients with moderately controlled glucose (3.9 mmol/L≤ FPG <7.0 mmol/L). Likewise, both the primary end point and secondary end point were found to be worse in DM patients with poorly controlled blood glucose (FPG ≥7.0 mmol/L). CONCLUSIONS: IFG and DM were associated with higher all-cause mortality and cardiovascular mortality in patients with acute HF. The association between mortality and admission FPG in DM patients with acute HF appeared U-shaped.

Role of Circulating Fibrocytes in Cardiac Fibrosis.

OBJECTIVE: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis. DATA SOURCES: This review is based on the data from 1994 to present obtained from PubMed. The search terms were "circulating fibrocytes " and "cardiac fibrosis ". STUDY SELECTION: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected. RESULTS: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics of hematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+). They can produce extracellular matrix and many cytokines. It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis. Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts. CONCLUSIONS: Circulating fibrocytes are effector cells in cardiac fibrosis.

Effect of Metabolic Syndrome on Risk Stratification for Left Atrial or Left Atrial Appendage Thrombus Formation in Patients with Nonvalvular Atrial Fibrillation.

BACKGROUND: Metabolic syndrome (MS) is a risk factor for stroke and thromboembolism event. Left atrial or LA appendage (LA/LAA) thrombus is a surrogate of potential stroke. The relationship between MS and atrial thrombus remains unclear. In this study, we sought to investigate the effect of MS on risk stratification of LA/LAA thrombus formation in patients with nonvalvular atrial fibrillation (NVAF). METHODS: This cross-sectional study enrolled 294 consecutive NVAF patients without prior anticoagulant and lipid-lowering therapies. LA/LAA thrombus was determined by transesophageal echocardiography. Risk assessment of LA/LAA thrombus was performed using the CHADS2 , CHA2DS2 -VASc, MS, CHADS2 -MS, and CHA2DS2 -VASc-MS scores. Logistic regression analyses were performed to determine which factors were significantly related to LA/LAA thrombus. Odds ratio (OR) including 95% confidence interval was also calculated. The predictive powers of different scores for the risk of LA/LAA thrombus were represented by C-statistics and compared by receiver operating characteristic (ROC) analysis. RESULTS: LA/LAA thrombi were identified in 56 patients (19.0%). Logistic analysis showed that MS was the strongest risk factor for LA/LAA thrombus in NVAF patients (OR = 14.698, P < 0.001). ROC curve analyses revealed that the C-statistics of CHADS2 -MS and CHA2DS2 -VASc-MS was significantly higher than those of CHADS2 and CHA2DS2 -VASc scores (CHADS2 -MS vs. CHADS2 , 0.807 vs. 0.726, P = 0.0019). Furthermore, MS was helpful for identifying individuals with a high risk of LA/LAA thrombus in the population with a low risk of stroke (CHADS2 or CHA2DS2 -VASc score = 0). CONCLUSIONS: MS is associated with LA/LAA thrombus risk in patients with NVAF. In addition to the CHADS2 and CHA2DS2 -VASc scores, the CHADS2 -MS and CHA2DS2 -VASc-MS scores provide additional information on stroke risk assessment.

Knockdown of EMMPRIN improves adverse remodeling mediated by IL-18 in the post-infarcted heart.

Interleukin-18 (IL-18) exacerbates cardiac dysfunction following myocardial infarction (MI). Extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to exacerbate ventricular remodeling via induction of extracellular matrix metalloproteinase (MMP) synthesis. While up-regulation of EMMPRIN expression by IL-18 has been demonstrated in vitro, little is known regarding its in vivo effects. Here, we investigated the role of EMMPRIN in progressive post-infarct ventricular remodeling induced by IL-18. Cardiac function was impaired on echocardiography and organ weight was increased in mice receiving daily intraperitoneal injection of IL-18 following MI. Accompanying these adverse functional effect were increased EMMPRIN levels. Gene silencing of cardiac EMMPRIN by intramyocardial RNA interference rescued IL-18 mediated adverse effects on post-infarct cardiac function. Finally, EMMPRIN silencing reduced MMP-9 expression in the post-infarcted left ventricular myocardium. In conclusion, progressive post-infarct left ventricular remodeling induced by IL-18 can be reversed by gene silencing of EMMPRIN. Knock down of EMMPRIN may be a potential therapeutic strategy to abrogate the adverse effects of IL-18 on post-infarct left ventricular remodeling likely via MMP-9 inhibition.

Interleukin 18 and extracellular matrix metalloproteinase inducer cross-regulation: implications in acute myocardial infarction.

Circulating interleukin-18 (IL-18) is thought to promote atherosclerosis and cardiovascular complications such as plaque rupture. Atherosclerosis is also characterized by smooth muscle cell migration, a consequence of extracellular matrix (ECM) degradation regulated by metalloproteinases (MMPs). Because extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to promote plaque instability by inducing ECM degradation and MMP synthesis, we investigated whether a cross-regulatory interaction exists between IL-18 and EMMPRIN in human monocytes. EMMPRIN levels in monocytes were markedly greater in 20 patients with acute myocardial infarction (AMI) compared with 20 patients with stable angina pectoris or 20 healthy volunteers (control group). The levels of IL-18 and MMP-9 in serum were also significantly greater in the AMI group in comparison with the other 2 groups. IL-18 levels positively correlated with increased levels of EMMPRIN in monocytes. In vitro, the expression of EMMPRIN was increased in monocytes cultured with IL-18, and IL-18 secretion was augmented in monocytes cultured with EMMPRIN. Gene silencing of EMMPRIN by small interfering RNA reduced monocyte secretion of both IL-18 and MMP-9. In the present study, cross-regulation between IL-18 and EMMPRIN in monocytes was demonstrated. This interaction may amplify the inflammatory cascade and be responsible for increased monocytic MMP-9 serum levels in atherosclerosis, contributing to atherosclerotic plaque destabilization and subsequent AMI.

Knockdown of the HDAC1 promotes the directed differentiation of bone mesenchymal stem cells into cardiomyocytes.

Failure of the directed differentiation of the transplanted stem cells into cardiomyocytes is still a major challenge of cardiac regeneration therapy. Our recent study has demonstrated that the expression of histone deacetylase 1 (HDAC1) is decreased in bone mesenchymal stem cells (BMSCs) during their differentiation into cardiomyocytes. However, the potential roles of HDAC1 in cardiac cell differentiation of BMSCs, as well as the mechanisms involved are still unclear. In current study, the expression of HDAC1 in cultured rat BMSCs is knocked down by lentiviral vectors expressing HDAC1-RNAi. The directed differentiation of BMSCs into cardiomyocytes is evaluated by the expression levels of cardiomyocyte-related genes such as GATA-binding protein 4 (GATA-4), Nirenberg, Kim gene 2 homeobox 5 (Nkx2.5), cardiac troponin T (CTnT), myosin heavy chain (MHC), and connexin-43. Compared with that in control BMSCs, the expression of these cardiomyocyte-related genes is significantly increased in these HDAC1 deficient stem cells. The results suggest that HDAC1 is involved in the cardiomyocyte differentiation of BMSCs. Knockdown of the HDAC1 may promote the directed differentiation of BMSCs into cardiomyocytes.

Downregulation of HDAC1 is involved in the cardiomyocyte differentiation from mesenchymal stem cells in a myocardial microenvironment.

Under myocardial microenvironment, bone marrow-derived mesenchymal stem cells (MSCs) can transdifferentiate into cardiomyocytes (CMs). However, the role of histone deacetylase 1 (HDAC1) in this directed differentiation process remains unclear. The current study is to determine the acetylation regulatory mechanisms that may be involved in the directed CM differentiation from MSCs. MSCs isolated from male Sprague-Dawley (SD) rats were marked with Ad-EGFP and co-cultured with CMs. Flow cytometry was used to sort EGFP-positive (EGFP+) MSCs from the co-culture system. Then, the expression of cardiac troponin T (cTnT) in these MSCs was detected by immunofluorescence assay. In addition, HDAC1 levels at different co-culture times were measured by quantitative real-time polymerase chain reaction (QT-PCR) and Western blotting. At 4 days after co-culture with CMs, the MSCs began to expression detectable levels of cTnT. The expression of HDAC1 in CMs was much lower than that in MSCs. After co-culture with CMs, the expression of HDAC1 in MSCs was significantly decreased in a time dependent manner. In addition, our recent study has also identified that knockdown of the HDAC1 could promote the directed differentiation of MSCs into CMs. The results suggest that HDAC1 has a negative correlation with cardiac cell differentiation from MSCs under a myocardial microenvironment. HDAC1 might play an important role in the directed differentiation of MSCs into CMs in heart.