Prohibitin 1 inhibits cell proliferation and induces apoptosis via the p53-mediated mitochondrial pathway in vitro.

BACKGROUND: Prohibitin 1 (PHB1) has been identified as an antiproliferative protein that is highly conserved and ubiquitously expressed, and it participates in a variety of essential cellular functions, including apoptosis, cell cycle regulation, proliferation, and survival. Emerging evidence indicates that PHB1 may play an important role in the progression of hepatocellular carcinoma (HCC). However, the role of PHB1 in HCC is controversial. AIM: To investigate the effects of PHB1 on the proliferation and apoptosis of human HCC cells and the relevant mechanisms in vitro. METHODS: HCC patients and healthy individuals were enrolled in this study according to the inclusion and exclusion criteria; then, PHB1 levels in the sera and liver tissues of these participates were determined using ELISA, RT-PCR, and immunohistochemistry. Human HepG2 and SMMC-7721 cells were transfected with the pEGFP-PHB1 plasmid and PHB1-specific shRNA (shRNA-PHB1) for 24-72 h. Cell proliferation was analysed with an MTT assay. Cell cycle progression and apoptosis were analysed using flow cytometry (FACS). The mRNA and protein expression levels of the cell cycle-related molecules p21, Cyclin A2, Cyclin E1, and CDK2 and the cell apoptosis-related molecules cytochrome C (Cyt C), p53, Bcl-2, Bax, caspase 3, and caspase 9 were measured by real-time PCR and Western blot, respectively. RESULTS: Decreased levels of PHB1 were found in the sera and liver tissues of HCC patients compared to those of healthy individuals, and decreased PHB1 was positively correlated with low differentiation, TNM stage III-IV, and alpha-fetoprotein ≥ 400 µg/L. Overexpression of PHB1 significantly inhibited human HCC cell proliferation in a time-dependent manner. FACS revealed that the overexpression of PHB1 arrested HCC cells in the G0/G1 phase of the cell cycle and induced apoptosis. The proportion of cells in the G0/G1 phase was significantly increased and the proportion of cells in the S phase was decreased in HepG2 cells that were transfected with pEGFP-PHB1 compared with untreated control and empty vector-transfected cells. The percentage of apoptotic HepG2 cells that were transfected with pEGFP-PHB1 was 15.41% ± 1.06%, which was significantly greater than that of apoptotic control cells (3.65% ± 0.85%, P < 0.01) and empty vector-transfected cells (4.21% ± 0.52%, P < 0.01). Similar results were obtained with SMMC-7721 cells. Furthermore, the mRNA and protein expression levels of p53, p21, Bax, caspase 3, and caspase 9 were increased while the mRNA and protein expression levels of Cyclin A2, Cyclin E1, CDK2, and Bcl-2 were decreased when PHB1 was overexpressed in human HCC cells. However, when PHB1 was upregulated in human HCC cells, Cyt C expression levels were increased in the cytosol and decreased in the mitochondria, which indicated that Cyt C had been released into the cytosol. Conversely, these effects were reversed when PHB1 was knocked down. CONCLUSION: PHB1 inhibits human HCC cell viability by arresting the cell cycle and inducing cell apoptosis via activation of the p53-mediated mitochondrial pathway.

Effectiveness of enhanced recovery after surgery in the perioperative management of patients with bone surgery in China.

BACKGROUND: Enhanced recovery after surgery (ERAS) was introduced in China in 2007. Over time, the scope of ERAS has expanded from abdominal surgery to orthopedics, urology and other fields. Continuous development and research has contributed to progress of ERAS in China. In 2019, to promote the application of ERAS in bone tumor surgery, we formed the "Consensus of Experts on Perioperative Management of Accelerated Rehabilitation in Major Surgery of Bone Tumors in China". AIM: To evaluate the effect of enhanced recovery after bone tumor surgery in perioperative management in China. METHODS: One hundred and seven patients who underwent bone tumor surgery at the Second Affiliated Hospital of Xi'an Jiaotong University between May 2019 and April 2021 were randomized into a study group (53 cases) and a control group (54 cases). The study group adopted the ERAS protocol and the control group adopted conventional care. Main outcome measures included postoperative length of stay (LOS), postoperative complications, mortality, and 30-d readmission rates. Secondary outcomes included postoperative visual analog scale (VAS) score of pain, number of blood transfusions, drainage volume in 24 h after operation, patient satisfaction 30 d after discharge, VAS score at 30 d after discharge, and daily standing walking time. RESULTS: There were no significant differences in the baseline data, clinical features and surgical site between the two groups. The LOS in the study group with the ERAS protocol was 7.72 ± 3.34 d compared with 10.28 ± 4.27 d in the control group who followed conventional care. The incidence of postoperative nausea and vomiting (PONV) in the study group was 19% and 37% in the control group. The VAS scores of pain on postoperative day 1 (POD1) and POD3 in the study group were 4.79 ± 2.34 and 2.79 ± 1.53 compared with 5.28 ± 3.27 and 3.98 ± 2.27 in the control group. The drainage volume in 24 h after the operation was 124.36 ± 23.43 mL in the study group and 167.43 ± 30.87 mL in the control group. The number of blood transfusions in the study group was also lower. The patient satisfaction rate was higher in the study group than in the control group. CONCLUSION: The ERAS protocol in the perioperative period of bone tumor surgery can decrease LOS, PONV, and postoperative pain, blood transfusion and 24-h drainage, improve patient satisfaction and accelerate recovery.

Irisin attenuates angiotensin II-induced cardiac fibrosis via Nrf2 mediated inhibition of ROS/ TGFß1/Smad2/3 signaling axis.

Angiotensin II-related cardiac fibrosis is one of the key pathological changes of the hypertrophied left ventricle in various heart disease. Irisin was recently reported to confer cardio-protective and anti-oxidative effects, while whether it can reverse the renin-angiotensin-aldosterone system(RAAS) activation related(angiotensin II-induced) cardiac fibrosis is unknown. In this study, we found that angiotensin II-induced cardiac dysfunction and fibrotic responses were dampened by irisin treatment in mice. Mechanistically, angiotensin II induced robust ROS generation, which in turn triggered activation of pro-fibrotic TGFß1-Smad2/3 signaling and subsequent collagen synthesis and fibroblast-myofibroblast transformation in cardiac fibroblasts. In contrast, Irisin treatment suppressed angiotensin II-induced ROS generation, TGFß1 activation, collagen synthesis and fibroblast-myofibroblast transformation, the effects of which was accompanied by Nrf2 activation and also abolished by a Nrf2 targeted siRNA. Taken together, we here identified irisin as a promising anti-fibrotic therapeutic for angiotensin II-related cardiac fibrosis.

Cilostazol suppresses angiotensin II-induced apoptosis in endothelial cells.

Patients with essential hypertension undergo endothelial dysfunction, particularly in the conduit arteries. Cilostazol, a type III phosphodiesterase inhibitor, serves a role in the inhibition of platelet aggregation and it is widely used in the treatment of peripheral vascular diseases. Previous studies have suggested that cilostazol suppresses endothelial dysfunction; however, it remains unknown whether cilostazol protects the endothelial function in essential hypertension. The aim of the present study was to investigate whether, and how, cilostazol suppresses angiotensin II (angII)­induced endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) and Sprague Dawley rats were exposed to angII and treated with cilostazol. Endothelial cell apoptosis and function, nitric oxide and superoxide production, phosphorylation (p) of Akt, and caspase­3 protein expression levels were investigated. AngII exposure resulted in the apoptosis of endothelial cells in vitro and in vivo. In vitro, cilostazol significantly suppressed the angII­induced apoptosis of HUVECs; however, this effect was reduced in the presence of LY294002, a phosphoinositide 3 kinase (PI3K) inhibitor. Furthermore, cilostazol suppressed the angII­induced p­Akt downregulation and cleaved caspase­3 upregulation. These effects were also alleviated by LY294002. In vivo, cilostazol suppressed the angII­induced endothelial cell apoptosis and dysfunction. Cilostazol was also demonstrated to partially reduced the angII­induced increase in superoxide production. The results of the present study suggested that cilostazol suppresses endothelial apoptosis and dysfunction by modulating the PI3K/Akt pathway.

Three-dimensional poly-(ε-caprolactone) nanofibrous scaffolds directly promote the cardiomyocyte differentiation of murine-induced pluripotent stem cells through Wnt/ß-catenin signaling.

BACKGROUND: Environmental factors are important for stem cell lineage specification, and increasing evidence indicates that the nanoscale geometry/topography of the extracellular matrix (ECM) directs stem cell fate. Recently, many three-dimensional (3D) biomimetic nanofibrous scaffolds resembling many characteristics of the native ECM have been used in stem cell-based myocardial tissue engineering. However, the biophysical role and underlying mechanism of 3D nanofibrous scaffolds in cardiomyocyte differentiation of induced pluripotent stem cells (iPSCs) remain unclear. RESULTS: Here, we fabricated a 3D poly-(ε-caprolactone) (PCL) nanofibrous scaffold using the electrospinning method and verified its nanotopography and porous structure by scanning electron microscopy. We seeded murine iPSCs (miPSCs) directly on the 3D PCL nanofibrous scaffold and initiated non-directed, spontaneous differentiation using the monolayer method. After the 3D PCL nanofibrous scaffold was gelatin coated, it was suitable for monolayer miPSC cultivation and cardiomyocyte differentiation. At day 15 of differentiation, miPSCs differentiated into functional cardiomyocytes on the 3D PCL nanofibrous scaffold as evidenced by positive immunostaining of cardiac-specific proteins including cardiac troponin T (cTnT) and myosin light chain 2a (MLC2a). In addition, flow cytometric analysis of cTnT-positive cells and cardiac-specific gene and protein expression of cTnT and sarcomeric alpha actinin (α-actinin) demonstrated that the cardiomyocyte differentiation of miPSCs was more efficient on the 3D PCL nanofibrous scaffold than on normal tissue culture plates (TCPs). Furthermore, early inhibition of Wnt/ß-catenin signaling by the selective antagonist Dickkopf-1 significantly reduced the activity of Wnt/ß-catenin signaling and decreased the cardiomyocyte differentiation of miPSCs cultured on the 3D PCL nanofibrous scaffold, while the early activation of Wnt/ß-catenin signaling by CHIR99021 further increased the cardiomyocyte differentiation of miPSCs. CONCLUSION: These results indicated that the electrospun 3D PCL nanofibrous scaffolds directly promoted the cardiomyocyte differentiation of miPSCs, which was mediated by the activation of the Wnt/ß-catenin signaling during the early period of differentiation. These findings highlighted the biophysical role of 3D nanofibrous scaffolds during the cardiomyocyte differentiation of miPSCs and revealed its underlying mechanism involving Wnt/ß-catenin signaling, which will be helpful in guiding future stem cell- and scaffold-based myocardium bioengineering.

Low-Level Electrical Stimulation of Aortic Root Ventricular Ganglionated Plexi Attenuates Autonomic Nervous System-Mediated Atrial Fibrillation.

OBJECTIVES: This study investigated the effect of electrical stimulation of aortic root ventricular ganglionated plexi (GP) on atrial fibrillation (AF) inducibility. BACKGROUND: The ventricular GP are interconnected with atrial GP to govern heart function, although the effect of ventricular GP modification on control of AF remains unknown. METHODS: Effective refractory periods (ERPs) of test pulmonary veins (PVs) were measured at baseline and during high-level (HL-ES) and low-level (LL-ES) electrical stimulation of the aortic root GP. The arrhythmogenic threshold of acetylcholine and isoproterenol was determined at baseline and during HL-ES and LL-ES. Moreover, AF was induced at PVs by programmed electrical stimulation after HL-ES or LL-ES. Immunohistochemistry staining was performed to examine the autonomic activity from aortic root GP to the PVs. RESULTS: Compared with the baseline group, HL-ES of aortic root GP significantly shortened atrial ERP (95 ± 13 ms vs. 122 ± 9 ms) and PV ERP (104 ± 11 ms vs. 131 ± 12 ms); decreased the threshold concentration of AF by both acetylcholine (1.3 ± 0.2 µmol/l vs. 3.2 ± 0.3 µmol/l) and isoproterenol (0.3 ± 0.1 µmol/l vs. 1.3 ± 0.2 µmol/l); and increased the AF-inducing rate from PVs (90% vs. 30%). In contrast, LL-ES of the GP prevented the shortening of ERP and PV ERP to 125 ± 10 ms and 133 ± 11 ms, respectively; increased threshold levels of acetylcholine and isoproterenol to 5.7 ± 0.4 µmol/l and 3.2 ± 0.3 µmol/l; and decreased the AF-inducing rate to 5%. We also found that the biotinylated dextran amine-containing varicose fibers projected directly from the aortic root GP to the left PVs. CONCLUSIONS: These findings suggest that autonomic innervations of left PVs partly originated from aortic root ventricular GP. Moreover, LL-ES of aortic root ventricular GP suppressed AF inducibility and arose from PVs mediated by the autonomic nervous system.

The long-term differentiation of embryonic stem cells into cardiomyocytes: an indirect co-culture model.

BACKGROUND: Embryonic Stem Cells (ESCs) can differentiate into cardiomyocytes (CMs) in vitro but the differentiation level from ESCs is low. Here we describe a simple co-culture model by commercially available Millicell™ hanging cell culture inserts to control the long-term differentiation of ESCs into CMs. METHODOLOGY/PRINCIPAL FINDINGS: Mouse ESCs were cultured in hanging drops to form embryoid bodies (EBs) and treated with 0.1 mmol/L ascorbic acid to induce the differentiation of ESCs into CMs. In the indirect co-culture system, EBs were co-cultured with epidermal keratinocytes (EKs) or neonatal CMs (NCMs) by the hanging cell culture inserts (PET membranes with 1 µm pores). The molecular expressions and functional properties of ESC-derived CMs in prolonged culture course were evaluated. During time course of ESC differentiation, the percentages of EBs with contracting areas in NCMs co-culture were significantly higher than that without co-culture or in EKs co-culture. The functional maintenance of ESC-derived CMs were more prominent in NCMs co-culture model. CONCLUSIONS/SIGNIFICANCE: These results indicate that NCMs co-culture promote ESC differentiation and has a further effect on cell growth and differentiation. We assume that the improvement of the differentiating efficiency of ESCs into CMs in the co-culture system do not result from the effect of co-culture directly on cell differentiation, but rather by signaling effects that influence the cells in proliferation and long-term function maintenance.

Collagen/ß(1) integrin interaction is required for embryoid body formation during cardiogenesis from murine induced pluripotent stem cells.

BACKGROUND: The interactions between stem cells and extracellular matrix (ECM) mediated by integrins play important roles in the processes that determine stem cell fate. However, the role of ECM/integrin interaction in the formation of embryoid bodies (EBs) during cardiogenesis from murine induced pluripotent stem cells (miPSCs) remains unclear. RESULTS: In the present study, collagen type I and ß(1) integrin were expressed and upregulated synergistically during the formation of miPSC-derived EBs, with a peak expression at day 3 of differentiation. The blockage of collagen/ß(1) integrin interaction by ß(1) integrin blocking antibody resulted in the production of defective EBs that were characterized by decreased size and the absence of a shell-like layer composed of primitive endoderm cells. The quantification of spontaneous beating activity, cardiac-specific gene expression and cardiac troponin T (cTnT) immunostaining showed that the cardiac differentiation of these defective miPSC-derived EBs was lower than that of control EBs. CONCLUSIONS: These findings indicate that collagen/ß(1) integrin interaction is required for the growth and cardiac differentiation of miPSC-derived EBs and will be helpful in future engineering of the matrix microenvironment within EBs to efficiently direct the cardiac fate of pluripotent stem cells to promote cardiovascular regeneration.

High-mobility group box 1 induces calcineurin-mediated cell hypertrophy in neonatal rat ventricular myocytes.

Cardiac hypertrophy is an independent predictor of cardiovascular morbidity and mortality. In recent years, evidences suggest that high-mobility group box 1 (HMGB1) protein, an inflammatory cytokine, participates in cardiac remodeling; however, the involvement of HMGB1 in the pathogenesis of cardiac hypertrophy remains unknown. The aim of this study was to investigate whether HMGB1 is sufficient to induce cardiomyocyte hypertrophy and to identify the possible mechanisms underlying the hypertrophic response. Cardiomyocytes isolated from 1-day-old Sprague-Dawley rats were treated with recombinant HMGB1, at concentrations ranging from 50 ng/mL to 200 ng/mL. After 24 hours, cardiomyocytes were processed for the evaluation of atrial natriuretic peptide (ANP) and calcineurin A expression. Western blot and real-time RT-PCR was used to detect protein and mRNA expression levels, respectively. The activity of calcineurin was also evaluated using a biochemical enzyme assay. HMGB1 induced cardiomyocyte hypertrophy, characterized by enhanced expression of ANP, and increased protein synthesis. Meanwhile, increased calcineurin activity and calcineurin A protein expression were observed in cardiomyocytes preconditioned with HMGB1. Furthermore, cyclosporin A pretreatment partially inhibited the HMGB1-induced cardiomyocyte hypertrophy. Our findings suggest that HMGB1 leads to cardiac hypertrophy, at least in part through activating calcineurin.

Serum omentin-1 levels are inversely associated with the presence and severity of coronary artery disease in patients with metabolic syndrome.

CONTEXT: Omentin-1, an adipokine secreted from visceral adipose tissue, has been reported to be associated with coronary artery disease (CAD) and metabolic disorders. OBJECTIVE: To clarify the relationship between serum omentin-1 levels and the presence and severity of CAD in patients with metabolic syndrome (MetS). METHODS: We measured serum omentin-1 levels in 175 consecutive patients with MetS and in 46 controls. RESULTS: Serum omentin-1 levels are inversely associated with the presence and angiographic severity of CAD in MetS patients. CONCLUSIONS: Serum omentin-1 might be a potential biomarker to predict the development and progression of CAD in MetS patients.

Three-dimensional co-culture facilitates the differentiation of embryonic stem cells into mature cardiomyocytes.

The cardiomyocyte (CM) differentiation of embryonic stem cells (ESCs) is routinely cultured as two-dimensional (2D) monolayer, which doesn't mimic in vivo physiological environment and may lead to low differentiated level of ESCs. Here, we develop a novel strategy that enhances CM differentiation of ESCs in collagen matrix three-dimensional (3D) culture combined with indirect cardiac fibroblasts co-culture. ESCs were cultured in hanging drops to form embryoid bodies (EBs) and then applied on collagen matrix. The EBs were indirectly co-cultured with cardiac fibroblasts by the hanging cell culture inserts (PET 1 µm). The molecular expressions and ultrastructural characteristics of ESC-derived CMs (ESCMs) were analyzed by real time RT-PCR, immunocytochemistry, and Transmission Electron Microscopy (TEM). We found that the percentage of beating EBs with cardiac fibroblasts co-culture was significantly higher than that without co-culture after differentiation period of 8 days. Type I collagen used as 3D substrates enhanced the late-stage CM differentiation of ESCs and had effect on ultrastructural mature of ESCMs in late-stage development. The combined effects of 3D and co-culture that mimic in vivo physiological environment further improved the efficiency of CM differentiation from ESCs, resulting in fiber-like structures of cardiac cells with organized sarcomeric structure in ESCMs. This novel 3D co-culture system emphasizes the fact that the ESC differentiation is actively responding to cues from their environment and those cues can drive phenotypic control, which provides a useful in vitro model to investigate CM differentiation of stem cells.

Postprocedural serum sLOX-1 levels are associated with coronary in-stent restenosis in patients with stable coronary artery disease.

OBJECTIVES: We tested whether serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) levels are able to predict in-stent restenosis (ISR) after successful primary percutaneous coronary intervention (PCI). METHODS: Preprocedural and postprocedural serum sLOX-1 levels were measured in 210 consecutive patients with stable coronary artery disease who underwent successful primary PCI for de novo lesions. The patients were grouped as ISR and non-ISR based on angiographic follow-up results. RESULTS: PCI significantly increased serum sLOX-1 levels both in patients with [0.85 (range: 0.63-0.98) vs. 0.39 (range: 0.27-0.54) ng/ml, P < 0.01] or without ISR [0.45 (range: 0.36-0.84) vs. 0.32 (range: 0.28-0.62) ng/ml, P < 0.01]. Postprocedural serum sLOX-1 levels were higher in patients with ISR than those without ISR [0.85 (range: 0.63-0.98) vs. 0.45 (range: 0.36-0.84) ng/ml, P < 0.01]. High postprocedural serum sLOX-1 levels served as independent predictors of ISR (odds ratio: 3.040, 95% confidence interval: 1.359-6.802, P < 0.01). Furthermore, postprocedural serum sLOX-1 levels were correlated with late lumen loss of the stented lesions (ρ = 0.36, P < 0.01). CONCLUSION: Postprocedural serum sLOX-1 levels are significantly associated with the risk of ISR and the severity of lumen loss in patients with stable coronary artery disease undergoing primary PCI. These results suggested that postprocedural serum sLOX-1 levels might be useful for the detection and risk assessment of ISR after PCI.

[The relationship between reactive oxygen species-dependent activation of p38 MAPK and the expression of tumor necrosis factor-α in cultured cardiomyocytes].

AIM: To investigate the role of p38 mitogen-activated protein kinase(MAPK) in lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) expression in neonatal rat cardiomyocytes and to determine the relationship between reactive oxygen species (ROS) and p38 MAPK activation. METHODS: Cardiomyocytes were isolated from neonatal Sprague-Dawley rats and cultured by differential adhesion. Expression of TNF-α was determined in culture medium by ELISA. Activation of p38 MAPK was determined by Western blot analysis with phospho-specific antibody. ROS generation in cardiomyocytes was determined by peroxide specific probe 2', 7'-dichlorofluorescin diacetate (DCF-DA). RESULTS: In cardiomyocytes stimulated with LPS, the content of TNF-α in culture medium correlated with the activity of p38 MAPK in a time-dependent manner. The activation of p38 was observed after stimulation of 1 mg/L LPS for 1 h. TNF-α accumulated significantly in culture medium at 3 h after stimulation of LPS (P<0.05), which was remarkably attenuated by pretreatment with p38 MAPK specific inhibitor SB203580 (P<0.01). Furthermore, the production of ROS in cardiomyocytes stimulated with LPS was also increased at 1 h after stimulation of LPS, consistent with p38 MAPK activity. Pretreatment with antioxidants such as N-acetylcysteine and diphenyleneiodonium significantly inhibited the activation of p38 MAPK compared with LPS control (P<0.05). There was no significance in the activity of p38 MAPK among antioxidants pretreatment and non-LPS control groups. CONCLUSION: The activation of p38 MAPK plays an important role in TNF-α expression in LPS-stimulated cardiomyocytes and the increase of ROS production is prerequisite for the activation of p38 MAPK.

Serum sLOX-1 levels are associated with the presence and severity of angiographic coronary artery disease in patients with metabolic syndrome.

PURPOSE: Patients with metabolic syndrome are at high-risk for development of atherosclerosis and cardiovascular events. Serum soluble lectin-like oxidized low-density lipoprotein receptor-1(sLOX-1) is associated with coronary artery disease (CAD) and metabolic disorders. We sought to assess whether serum sLOX-1 levels are correlated with the presence and severity of CAD in patients with metabolic syndrome (MetS) undergoing coronary angiography. METHODS: Serum sLOX-1 levels were measured in 112 consecutive patients with MetS, undergoing coronary angiography for the evaluation of CAD. The severity of CAD was assessed by angiographic Gensini score system. RESULTS: Serum sLOX-1 levels were significantly higher in MetS patients with CAD (n=69) than in those without CAD (n=43) (0.925 [range 0.137 to 1.432] ng/ml vs. 0.207 [range 0.063 to 0.774] ng/ml, P < 0.01). Multivariate logistic regression analysis revealed that serum sLOX-1 level was independently associated with the presence of CAD (odds ratio 2.489, 95% confidence interval 1.290-4.802; P < 0.01). Serum sLOX-1 levels were positively correlated with the Gensini score (ρ: 0.394, P < 0.01) after adjusting for other clinical characteristics. CONCLUSIONS: High sLOX-1 levels are associated with the presence and severity of CAD in patients with MetS. The measurement of serum sLOX-1may be potentially useful in predicting the presence and severity of CAD in patients with MetS.

Simvastatin inhibits angiotensin II-induced cardiac cell hypertrophy: role of Homer 1a.

1. The scaffolding protein Homer 1a is constitutively expressed in the myocardium, although its function in cardiomyocytes remains poorly understood. The aim of the present study was to investigate Homer 1a expression in hypertrophic cardiac cells and its role in angiotensin (Ang) II-induced cardiac hypertrophy. 2. After serum starvation for 24 h, cells were treated with 1 micromol/L simvastatin, 100 nmol/L angiotensin (Ang) II or their combination added to Dulbecco's modified Eagle's medium containing 0.5% serum. For combination treatment with AngII plus simvastatin, cells were exposed to simvastatin 12 h before the addition of AngII to the medium and cells were then incubated in the presence of both drugs for a further 24 h. Western blotting was used to determine Homer 1a protein expression. Hypertrophy was evaluated by determining the protein content per cell. 3. Homer 1a protein levels were upregulated following AngII-induced hypertrophy in H9C2 cells and neonatal rat cardiomyocytes, and these increases were augmented by simvastatin pretreatment. Concomitantly, simvastatin pretreatment inhibited extracellular signal-regulated kinase (ERK) 1/2 phosphorylation and AngII-induced hypertrophy. 4. The inhibitory effects of simvastatin against AngII-induced hypertrophy were attenuated by Homer 1a silencing, suggesting that simvastatin suppresses cardiac hypertrophy in a Homer 1a-dependent manner. Furthermore, AngII-induced hypertrophy and ERK1/2 phosphorylation in neonatal rat cardiomyocytes were significantly inhibited following the overexpression of Homer 1a using an adenovirus. 5. These results suggest a possible role for Homer 1a in inhibiting cardiac hypertrophy perhaps in part through inhibition of ERK1/2 activation.

Heated lipiodol as an embolization agent for transhepatic arterial embolization in VX2 rabbit liver cancer model.

PURPOSE: To evaluate the therapeutic effect of heated (60 degrees C) lipiodol via hepatic artery administration in a rabbit model of VX2 liver cancer. MATERIALS AND METHODS: Thirty male New Zealand white rabbits were randomly divided into three groups with 10 rabbits assigned to each group. VX2 carcinoma cells were surgically implanted into the left hepatic lobe. The tumors were allowed to grow for 2 weeks, and studies were performed until the diameter of the tumors detected by ultrasonograph reached 2-3cm. Under anesthesia, trans-catheter hepatic arterial embolization was performed and doxorubicin-lipiodol (37 degrees C) (1mL), lipiodol (60 degrees C) (1mL) or control (physiological saline (37 degrees C) (1mL)) solution was injected into the hepatic arteries of animals in the three groups. One week later, the volume of the tumor was measured by ultrasonograph again. The serum of all rabbits was collected before injection and at 4 and 7 days after injection, and the level of aspartate aminotransferase (AST) was checked. The survival period of the three groups of rabbits after treatment was also recorded. During the last course of their disease, the rabbits were given analgesics to relieve suffering. RESULTS: The tumor growth rate in the lipiodol (60 degrees C) group (0.92+/-0.21, tumor volume from 1811+/-435 to 1670+/-564mm(3)) was significantly lower than that in the control group (3.48+/-1.17, tumor volume from 1808+/-756 to 5747+/-1341mm(3)) (P<0.05) and in the doxorubicin-lipiodol (37 degrees C) group (1.69+/-0.26, tumor volume from 1881+/-641 to 2428+/-752mm(3)) (P<0.05). Consequently, the survival period of the animals in the lipiodol (60 degrees C) group (41.0+/-3.0 days) was significantly greater than that in the doxorubicin-lipiodol (37 degrees C) group (38.0+/-2.5 days) (P<0.05). On the other hand, there was no statistically significant difference in serum AST levels between the lipiodol (60 degrees C) group (148.2+/-11.3UL(-1)) and the doxorubicin-lipiodol (37 degrees C) group (139.7+/-12.3UL(-1)) (P>0.05). However, the serum AST level in the lipiodol (60 degrees C) group was significantly higher at 4 days after injection (P<0.05) than in the control group (68.6+/-6.6UL(-1)). CONCLUSIONS: Treatment with lipiodol (60 degrees C) resulted in an effect on serum AST levels similar to that caused by treatment with doxorubicin-lipiodol (37 degrees C). Thus, lipiodol (60 degrees C) treatment could greatly prolong the survival period of rabbits with VX2 cancer by inhibiting tumor growth.

Controlling the in vitro differentiation of embryonic stem cells for myocardial tissue engineering applications.

We studied the differentiation of embryonic stem cells (ESCs) and developed a novel protocol for generating functional cardiomyocytes (CMs) from ESCs by co-culturing these with live cardiac cells. We then evaluated the structural and functional properties of these ESC-derived CMs (ESCMs). An acellular matrix obtained from rabbit heart tissues was used as a scaffold. Then ESCMs were seeded onto the acellular matrix for preliminary tissue engineering applications. We found that by mimicking the cardiac microenvironment, the percentage of beating embryoid bodies (EBs) was much higher and the homogeneity of EBs were significantly improved over that seen in the control group (p<0.001). ESCMs in EBs acquired almost the same structural and functional properties as typical CMs. After implantation, the cells in the EBs rapidly grew and expanded in the extracellular matrix. These results indicate that the differentiation of ESCs can be controlled in a cardiac mimicking microenvironment and that ESCs can be used as an ideal cell source for large-scale tissue engineering applications for the procurement of cardiac muscle.

Age-related changes in the atrial muscarinic type 2 receptor and their effects on atrial fibrillation vulnerability in rabbits.

Aging plays an important role in increased vulnerability to atrial fibrillation (AF). Mediated by activity at the muscarinic type 2 receptor (M2R), the parasympathetic nerve contributes to the onset of AF. The purpose of this study was to investigate whether aging changes the distribution of M2R in the atrial myocardium and to determine the impact of these changes on AF vulnerability. Expression of M2R in the atrial myocardium was evaluated by immunostaining and Western blot in three groups-young (3 months old), mature (8 months old) and senescent (36-48 months old) rabbits. AF inducibility was recorded with and without cervical vagal stimulation (VS) in vivo in all groups. AF inducibility, the atrial effective refractory period (AERP) and the monophasic action potential (MAP) were recorded in an additional seven senescent rabbits before and after topical administration of tropicamide. The results showed that the density of M2R in the left atrial free wall (LAFW) was significantly higher than that in other parts of the atria. The left atrial appendage had a higher level of M2R expression than the right atrium. The M2R density of the epicardial side was greater than that of endocardial side in both atria. The senescent group had a significant increase in M2R expression in the LAFW relative to the mature group. AF inducibility was also higher in the senescent group than in the other two groups. After tropicamide administration in the senescent rabbits, AF inducibility decreased significantly, the VS-induced decrease in AERP and MAP duration at 90% repolarization (MAPD90) of LAFW was attenuated, and the dispersion of the AERP and MAPD90 increase was attenuated. In conclusion, our results suggested that there is spatial heterogeneity in the M2R distribution in the atria of the rabbit. The density of M2R in the LAFW increased with the aging of rabbits. This change in M2R enhanced the heterogeneity of the M2R distribution and contributed to the change in age-related AF vulnerability.

Using embryonic stem cells to form a biological pacemaker via tissue engineering technology.

Biological pacemakers can be achieved by various gene-based and cell-based approaches. Embryonic stem cells (ESCs)-derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue-engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming of a construct with-defined architectures and functional properties. The combined interactions between ESC-derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self-renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue-engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue-engineering technology.