Conversion therapy in liver transplantation for hepatocellular carcinoma: What's new in the era of molecular and immune therapy?

BACKGROUND: Hepatocellular carcinoma (HCC) is the sixth most common cancer globally, with limited therapies and unsatisfactory prognosis once in the advanced stages. With promising advances in locoregional and systematic treatments, fast development of targeted drugs, the success of immunotherapy, as well as the emergence of the therapeutic alliance, conversion therapy has recently become more well developed and an effective therapeutic strategy. This article aimed to review recent developments in conversion therapy in liver transplantation (LT) for HCC. DATA SOURCES: We searched for relevant publications on PubMed before September 2022, using the terms "HCC", "liver transplantation", "downstaging", "bridging treatment" and "conversion therapy." RESULTS: Conversion therapy was frequently represented as a combination of multiple treatment modalities to downstage HCC and make patients eligible for LT. Although combining various local and systematic treatments in conversion therapy is still controversial, growing evidence has suggested that multimodal combined treatment strategies downstage HCC in a shorter time, which ultimately increases the opportunities for LT. Moreover, the recent breakthrough of immunotherapy and targeted therapy for HCC also benefit patients with advanced-stage tumors. CONCLUSIONS: In the era of targeted therapy and immunotherapy, applying the thinking of transplant oncology to benefit HCC patients receiving LT is a new topic that has shed light on advanced-stage patients. With the expansion of conversion therapy concepts, further investigation and research is required to realize the full potential of conversion treatment strategies, including accurately selecting candidates, determining the timing of surgery, improving the conversion rate, and guaranteeing the safety and long-term efficacy of treatment.

[Correlation between Cyclic GMP-AMP Synthase-Stimulator of Interferon Genes Signaling Pathway and Non-infectious Diseases].

As a DNA receptor in the cytoplasm,cyclic GMP-AMP synthase (cGAS) can recognize abnormal DNA in the cytoplasm and activate stimulator of interferon genes (STING) to regulate the immune response. The recent studies have demonstrated that this pathway plays a role in non-infectious inflammatory diseases by promoting the expression of type Ⅰ interferon and interferon-stimulated gene.This article reviews the activation and regulation of cGAS-STING pathway in multiple systems and the effect of this pathway on the occurrence and progression of non-infectious inflammatory diseases,providing theoretical reference for future application of cGAS-STING pathway-related drugs in non-infectious inflammatory diseases.

Aldehyde dehydrogenase 2 preserves mitochondrial morphology and attenuates hypoxia/reoxygenation-induced cardiomyocyte injury.

BACKGROUND: Disturbance of mitochondrial fission and fusion (termed mitochondrial dynamics) is one of the leading causes of ischemia/reperfusion (I/R)-induced myocardial injury. Previous studies showed that mitochondrial aldehyde dehydrogenase 2 (ALDH2) conferred cardioprotective effect against myocardial I/R injury and suppressed I/R-induced excessive mitophagy in cardiomyocytes. However, whether ALDH2 participates in the regulation of mitochondrial dynamics during myocardial I/R injury remains unknown. METHODS: In the present study, we investigated the effect of ALDH2 on mitochondrial dynamics and the underlying mechanisms using the H9c2 cells exposed to hypoxia/reoxygenation (H/R) as an in vitro model of myocardial I/R injury. RESULTS: Cardiomyocyte apoptosis was significantly increased after oxygen-glucose deprivation and reoxygenation (OGD/R), and ALDH2 activation largely decreased the cardiomyocyte apoptosis. Additionally, we found that both ALDH2 activation and overexpression significantly inhibited the increased mitochondrial fission after OGD/R. Furthermore, we found that ALDH2 dominantly suppressed dynamin-related protein 1 (Drp1) phosphorylation (Ser616) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation (Thr172) but not interfered with the expression levels of mitochondrial shaping proteins. CONCLUSIONS: We demonstrate the protective effect of ALDH2 against cardiomyocyte H/R injury with a novel mechanism on mitochondrial fission/fusion.

Hepatic epithelioid hemangioendothelioma: Update on diagnosis and therapy.

With an estimated incidence of only 1-2 cases in every 1 million people, hepatic epithelioid hemangioendothelioma (HEHE) is a rare vascular endothelial cell tumor occurring in the liver and consisting of epithelioid and histiocyte-like vascular endothelial cells in mucus or a fibrotic matrix. HEHE is characterized as a low-to-moderate grade malignant tumor and is classified into three types: solitary, multiple, and diffuse. Both the etiology and characteristic clinical manifestations of HEHE are unclear. However, HEHE has a characteristic appearance on imaging including ultrasound, magnetic resonance imaging, and positron emission tomography/computerized tomography. Still, its diagnosis depends mainly on pathological findings, with immunohistochemical detection of endothelial markers cluster of differentiation 31 (CD31), CD34, CD10, vimentin, and factor VIII antigen as the basis of diagnosis. Hepatectomy and/or liver transplantation are the first choice for treatment, but various chemotherapeutic drugs are reportedly effective, providing a promising treatment option. In this review, we summarize the literature related to the diagnosis and treatment of HEHE, which provides future perspectives for the clinical management of HEHE.

Regulatory mechanism of NOV/CCN3 in the inflammation and apoptosis of lung epithelial alveolar cells upon lipopolysaccharide stimulation.

Lipopolysaccharide (LPS) induces stress inflammation and apoptosis. Pulmonary epithelial cell apoptosis, which accelerates the progression of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), is the leading cause of mortality in patients with ALI/ARDS. The nephroblastoma overexpressed protein (CCN3), an inflammatory modulator, is reported to be a biomarker in ALI. Using the LPS-induced ALI model, this study investigated the expression of CCN3 and its possible molecular mechanism in lung alveolar epithelial cell inflammation and apoptosis. Our data revealed that LPS treatment greatly increased the level of CCN3 in A549 cells. The A549 cells were transfected with specific CCN3 small interfering RNA (siRNA) using transfection reagent. CCN3 siRNA not only largely attenuated the expressions of the inflammatory cytokines interleukin (IL)-1ß and transforming growth factor (TGF)-ß1, but also reduced the apoptotic rate of the AEC II cells and affected the expressions of the apoptosis-associated proteins (Bcl-2 and caspase-3). Furthermore, CCN3 knockdown greatly inhibited the activation of nuclear factor-κB p65 in A549 cells. In addition, TGF-ß/p-Smad inhibitor (TP0427736) and NF-κB inhibitor (PDTC) significantly attenuated the expression level of CCN3 in A549 cells. In conclusion, our data indicated that CCN3 siRNA affected downstream signal through TGF-ß/ p-Smad or NF-κB pathway, leading to the inhibition of cell inflammation and apoptosis in human alveolar epithelial cells.

Ezetimibe prevents myocardial remodeling in an obese rat model by inhibiting inflammation.

Inflammation plays an important role in the development of many obesity-related diseases. This study aimed to investigate the effect of ezetimibe on inflammation and myocardial remodeling in obese rats. A rat model of obesity was established, and myocardial damage was examined by transmission electron microscopy and Masson staining. Twenty obese rats were divided into two groups (n=10): obese group and ezetimibe group. Ten SD rats were used as controls. Western blot was performed to monitor the expression of P-p38MAPK and interleukin (IL)-6. Immunohistochemical staining was used to monitor the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. In the obese rats group, we observed increased inflammatory factors and myocardial hypertrophy. In contrast, the ezetimibe group exhibited decreased expression of inflammatory factors and an improvement in myocardial remodeling compared to the obese group. Mechanistically, we found that ezetimibe decreased P-p38MAPK, IL-6, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 levels in the hearts of the obese rats. Taken together, these results indicate that ezetimibe may improve myocardial remodeling in obese rats by inhibiting inflammation.

Aldehyde dehydrogenase 2 inhibits inflammatory response and regulates atherosclerotic plaque.

Previous studies demonstrated that aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, which eliminates ALDH2 activity down to 1%-6%, is a susceptibility gene for coronary disease. Here we investigated the underlying mechanisms based on our prior clinical and experimental studies. Male apoE-/- mice were transfected with GFP, ALDH2-overexpression and ALDH2-RNAi lentivirus respectively (n=20 each) after constrictive collars were placed around the right common carotid arteries. Consequently, ALDH2 gene silencing led to an increased en face plaque area, more unstable plaque with heavier accumulation of lipids, more macrophages, less smooth muscle cells and collagen, which were associated with aggravated inflammation. However, ALDH2 overexpression displayed opposing effects. We also found that ALDH2 activity decreased in atherosclerotic plaques of human and aged apoE-/- mice. Moreover, in vitro experiments with human umbilical vein endothelial cells further illustrated that, inhibition of ALDH2 activity resulted in elevating inflammatory molecules, an increase of nuclear translocation of NF-κB, and enhanced phosphorylation of NF-κB p65, AP-1 c-Jun, Jun-N terminal kinase and p38 MAPK, while ALDH2 activation could trigger contrary effects. These findings suggested that ALDH2 can influence plaque development and vulnerability, and inflammation via MAPK, NF-κB and AP-1 signaling pathways.

Elevated Preoperative Neutrophil-Lymphocyte Ratio Is Associated with Poor Prognosis in Hepatocellular Carcinoma Patients Treated with Liver Transplantation: A Meta-Analysis.

This study aims to investigate the prognostic value of neutrophil to lymphocyte ratio (NLR) in hepatocellular carcinoma (HCC) patients treated with liver transplantation (LT) through meta-analysis. Relevant articles were sought in PubMed, Embase, and Wangfang databases up to July 2015. A total of 1687 patients from 10 studies were included in this meta-analysis. Meta-analysis results showed that elevated NLR was significantly associated with poorer overall survival (OS) (HR = 2.71, 95% CI: 1.91-3.83) and poorer disease-free survival (DFS) (HR = 3.61, 95% CI: 2.23-5.84) in HCC patients treated with LT. Moreover, subgroup analysis showed the significant association between elevated preoperative NLR and poor prognosis was not altered by cutoff values of NLR or types of LT. Therefore, elevated preoperative NLR is associated with poor prognosis in HCC patients treated with LT. Preoperative NLR should be used to predict the prognosis of HCC after LT in our clinical work.

Prohibitin overexpression improves myocardial function in diabetic cardiomyopathy.

Prohibitin (PHB) is a highly conserved protein implicated in various cellular functions including proliferation, apoptosis, tumor suppression, transcription, and mitochondrial protein folding. However, its function in diabetic cardiomyopathy (DCM) is still unclear. In vivo, type 2 diabetic rat model was induced by using a high-fat diet and low-dose streptozotocin. Overexpression of the PHB protein in the model rats was achieved by injecting lentivirus carrying PHB cDNA via the jugular vein. Characteristics of type 2 DCM were evaluated by metabolic tests, echocardiography and histopathology. Rats with DCM showed severe insulin resistance, left ventricular dysfunction, fibrosis and apoptosis. PHB overexpression ameliorated the disease. Cardiofibroblasts (CFs) and H9c2 cardiomyoblasts were used in vitro to investigate the mechanism of PHB in altered function. In CFs treated with HG, PHB overexpression decreased expression of collagen, matrix metalloproteinase activity, and proliferation. In H9c2 cardiomyoblasts, PHB overexpression inhibited apoptosis induced by HG. Furthermore, the increased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was significantly decreased and the inhibited phosphorylation of Akt was restored in DCM. Therefore, PHB may be a new therapeutic target for human DCM.

Prognostic value of cytokeratin 19 in hepatocellular carcinoma: A meta-analysis.

BACKGROUND: Although many studies have investigated the relationship between cytokeratin 19 (CK-19) and hepatocellular carcinoma (HCC), the prognostic value of CK-19 in HCC remains inconclusive. METHODS: Eligible studies were sought in PubMed, Embase, Web of Science, Cochrane Library and Wanfang databases. Pooled hazard ratios (HRs) and odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated. RESULTS: 17 studies with 2943 patients were included in this meta-analysis. Meta-analysis results showed that CK-19 over-expression was significantly associated with overall survival (OS) (HR=1.60, 95% CI: 1.32-1.93, univariate analysis; HR=2.25, 95% CI: 1.79-2.83, multivariate analysis) and disease-free survival (DFS) (HR=1.68, 95% CI: 1.35-2.10, univariate analysis; HR=1.97, 95% CI: 1.54-2.53, multivariate analysis). Meanwhile, CK-19 over-expression was also correlated with decreased 1-year OS rate (OR=0.32, 95% CI: 0.21-0.50), 5-year OS rate (OR=0.44, 95% CI: 0.14-0.87) and 1-year DFS rate (OR=0.51, 95% CI: 0.34-0.76), but not with 5-year DFS rate (OR=0.62, 95% CI: 0.35-1.10). These results suggested that CK-19 over-expression was significantly associated with poor survival rate and early tumor recurrence rate in HCC patients. CONCLUSIONS: CK-19 can serve as an indicator of poor prognosis as well as a novel target for treatment in HCC.

Prognostic and clinicopathological significance of MACC1 expression in hepatocellular carcinoma patients: a meta-analysis.

OBJECTIVE: Metastasis-associated in colon cancer-1 (MACC1) has been reported to be overexpressed in diverse human malignancies. However, the prognostic and clinicopathological value of MACC1 in hepatocellular carcinoma (HCC) remains inconclusive. Therefore, we conducted this meta-analysis to investigate the association between MACC1 expression and the outcomes of HCC. METHODS: Relevant articles were searched in PubMed, Embase, Sciencedirect, CNKI, and Wanfang databases updated to October 2014. The pooled hazard ratios (HRs) and odds ratios (ORs) with their 95% confidence intervals (CIs) were assessed using STATA 10.0, and then the correlations of MACC1 expression with overall survival (OS), disease-free survival (DFS), and clinicopathological features were analyzed. RESULTS: 9 studies with a total of 1293 HCC patients were included in this meta-analysis. Our results showed that MACC1 over-expression was significantly associated with poor OS (HR = 2.30, 95% CI 1.47-3.59, univariate analysis; HR = 2.39, 95% CI 1.49-3.82, multivariate analysis), poor DFS (HR = 1.73, 95% CI 1.40-2.13, univariate analysis). Moreover, MACC1 over-expression was significantly associated with AFP level (OR = 1.31, 95% CI 1.03-1.68), tumor number (OR = 1.37, 95% CI 1.07-1.75), differentiation (OR = 2.37, 95% CI 1.46-3.83), TNM stage (OR = 2.89, 95% CI 2.18-3.82), vascular invasion (OR = 1.89, 95% CI 1.43-2.50), capsule invasion (OR = 2.89, 95% CI 1.40-5.94), and metastasis (OR = 2.66, 95% CI 1.16-6.10). CONCLUSION: MACC1 over-expression indicated poor survival rate, high recurrence rate, and aggressive biological behaviors. MACC1 can serve as an indicator of prognosis and a potential novel target for treatment in HCC patients.

S-Nitrosylation of proline-rich tyrosine kinase 2 involves its activation induced by oxygen-glucose deprivation.

Previous studies have demonstrated that activation of proline-rich tyrosine kinase 2 (PYK2) in cerebral ischemia is involved in the modulation of N-methyl-d-aspartate-type (NMDA) glutamate receptor activity and Ca(2+) dynamics, resulting in ischemic neuron death ultimately. A number of reports indicate that PYK2 is a redox sensitive kinase that must be activated by an estrogen-induced reactive oxygen species (ROS). However, the mechanism of PYK2 activation remains incompletely illustrated. Accumulating attention is focused on nitric oxide (NO, a free radical) which plays a critical role in cellular signal transduction through stimulus-coupled S-nitrosylation of cysteine residues. Here we reported that PYK2 over-expressed in human embryonic kidney (HEK293) cells was S-nitrosylated (forming SNO-PYK2) by reacting with GSNO, an exogenous NO donor, at one critical cysteine residue (Cys534) with a biotin switch assay. Moreover, our results showed that S-nitrosylation and phosphorylation of PYK2 over-expressed in SH-SY5Y cells was significantly increased after oxygen-glucose deprivation (OGD). We further investigated whether the activation (phosphorylation) of PYK2 was associated with S-nitrosylation following SH-SY5Y cells OGD. Our results showed that the cysteine534 residue (site of S-nitrosylation) mutant PYK2 over-expressed in SH-SY5Y cells diminished S-nitrosylation of PYK2 and inhibited its phosphorylation induced by OGD. In addition, overexpression of the mutant PYK2 protein could prevent nuclear accumulation and abrogate neuronal cell death compared to wild type PYK2 in SH-SY5Y cells induced by OGD. These data suggest that the activation of PYK2 following OGD may be modulated by S-nitrosylation, which provides a new avenue for stroke therapy by targeting the post-translational modification machinery.

Angiotensin-(1-7) treatment mitigates right ventricular fibrosis as a distinctive feature of diabetic cardiomyopathy.

In diabetic patients, left ventricular (LV) remodeling is highly prevalent; however, little is known about the impact of diabetes on right ventricular (RV) structure and function. We recently found that overexpression of angiotensin (ANG)-converting enzyme 2 (ACE2), which metabolizes ANG-II to ANG-(1-7) and ANG-I to ANG-(1-9), may improve LV remodeling in diabetic cardiomyopathy (DCM). Here, we aimed to assess whether LV remodeling and dysfunction are paralleled by RV alterations and the effects of ANG-(1-7) on RV remodeling in DCM. After 12 wk of diabetes induced by a single intraperitoneal injection of streptozotocin, rats were treated with saline, ANG-(1-7), perindopril, ANG-(1-7) plus perindopril, ANG-(1-7) plus Mas receptor antagonist A779, or ANG-(1-7) plus ANG-II type 2 receptor antagonist PD123319 for 4 wk. RV remodeling in diabetic rats was indicated by fibrosis of the RV free wall in the absence of hypertrophy and apoptosis. Treatment with ANG-(1-7) prevented diabetes-induced RV fibrosis and dysfunction. ANG-(1-7) (800 ng·kg(-1)·min(-1)) was superior to perindopril in improving RV fibrosis. The major mechanisms involved a complex interaction of ANG-II type 2 and Mas receptors for subsequent downregulation of ACE expression and activity and ANG-II type 1 receptor expression, as well as upregulation of ACE2 expression and activity and the expression of ANG-II type 2 receptor and sarco(endo)plasmic reticulum Ca(2+)-ATPase. Thus RV fibrosis and dysfunction plays a central role in DCM, and ANG-(1-7) mitigates diabetes-induced RV alterations.

Cadmium is a potent inhibitor of PPM phosphatases and targets the M1 binding site.

The heavy metal cadmium is a non-degradable pollutant. By screening the effects of a panel of metal ions on the phosphatase activity, we unexpectedly identified cadmium as a potent inhibitor of PPM1A and PPM1G. In contrast, low micromolar concentrations of cadmium did not inhibit PP1 or tyrosine phosphatases. Kinetic studies revealed that cadmium inhibits PPM phosphatases through the M1 metal ion binding site. In particular, the negative charged D441 in PPM1G specific recognized cadmium. Our results suggest that cadmium is likely a potent inhibitor of most PPM family members except for PHLPPs. Furthermore, we demonstrated that cadmium inhibits PPM1A-regulated MAPK signaling and PPM1G-regulated AKT signaling potently in vivo. Cadmium reversed PPM1A-induced cell cycle arrest and cadmium insensitive PPM1A mutant rescued cadmium induced cell death. Taken together, these findings provide a better understanding of the effects of the toxicity of cadmium in the contexts of human physiology and pathology.

Activin receptor-like kinase 7 mediates high glucose-induced H9c2 cardiomyoblast apoptosis through activation of Smad2/3.

Cardiomyocyte apoptosis is an important pathological change of diabetic cardiomyopathy. How the elevated glucose levels cause cell apoptosis remains unknown. The aim of our study was to investigate whether activin receptor-like kinase 7 (ALK7)-Smad2/3 signaling pathway plays an important role in high glucose-induced cardiomyocyte apoptosis. H9c2 cardiomyoblasts and neonatal rat cardiomyocytes were treated with 33mmol/l glucose. The expression of ALK7, Smad2 and Smad3 were inhibited by small interfering RNA respectively. The level of ALK7, total Smad2/3, phosphorylated Smad2/3, B-cell lymphoma-2 (Bcl-2) and cleaved Caspase3 were evaluated using western blot. The apoptosis rate was detected by flow cytometer. High glucose treatment caused the apoptosis of H9c2 cardiomyocyte and the inhibition of Smad2 or Smad3 attenuated this apoptosis. ALK7 existed in both H9c2 cardiomyoblasts and neonatal rat cardiomyocytes and high ambient glucose upregulated its expression. The increased expression level of cleaved Caspase3 and apoptosis rate and decreased expression of Bcl-2 were reversed after ALK7 was inhibited. The expression of phosphorylated Smad2/3 also decreased after the knockdown of ALK7. Our findings suggest that ALK7 mediates high ambient glucose-induced H9c2 cardiomyoblasts apoptosis through the activation of Smad2/3.

Tetramethylpyrazine upregulates the aquaporin 8 expression of hepatocellular mitochondria in septic rats.

BACKGROUND: The sepsis-induced acute liver injury majorly depends on the dysfunction of mitochondria and the loss of cellular energy. Aquaporin 8 (AQP8) can modulate water transport and osmotic swelling of mitochondria in the inner mitochondrial membrane of the liver. In this study, we explore the effects of tetramethylpyrazine (TMP) on protecting the structure of hepatocyte mitochondria and modulating the expression of AQP8. MATERIALS AND METHODS: Forty-eight rats were randomly allocated to four groups: control group receiving sham procedure, septic group receiving cecal ligation and puncture (CLP), therapeutic group receiving 60 mg/kg of ligustrazine (TMP) intravenously from caudal vein immediately after CLP, and preventive group receiving 60 mg/kg/d of ligustrazine intravenously from caudal vein for 7 d before CLP. The mitochondrial ultrastructure of rat liver was observed. The protein expression of AQP8 was assayed by Western blot. Analysis of AQP8 messenger RNA (mRNA) expression level was performed by the reverse transcription-polymerase chain reaction. The mean fluorescence intensity (MFI) of rhodamine 123 (Rh 123) was measured by flow cytometry. The serum tumor necrosis factor alpha (TNF-α) level was determined by the enzyme-linked immunosorbent assay. RESULTS: The mitochondrial ultrastructure was markedly damaged in the septic group, whereas it was lightly damaged in the therapeutic and preventive groups. Compared with the control group, the AQP8 protein expression and MFI were significantly reduced, and the steady-state AQP8 mRNA and serum TNF-α levels were increased in the septic, therapeutic, and preventive groups. Compared with the septic group, the AQP8 protein expression and MFI were increased, and the steady-state AQP8 mRNA and serum TNF-α levels were decreased significantly in the therapeutic and preventive groups. There was no significant difference in morphologic characteristics, AQP8 protein level, AQP8 mRNA level, MFI, and serum TNF-α level between the therapeutic and the preventive groups. Linear positive correlation was observed between the AQP8 protein level and the MFI of Rh 123. Linear negative correlation was observed between the AQP8 protein level or the MFI of Rh 123 and serum TNF-α level. CONCLUSIONS: TMP has protective effect on hepatocellular mitochondria from damage in sepsis by ameliorating the expression of AQP8 protein in liver mitochondria. The protective effect of TMP on the liver mitochondria might not have a difference between using TMP before or after the occurrence of sepsis.

Huang-lian-jie-du-tang protects rats from cardiac damages induced by metabolic disorder by improving inflammation-mediated insulin resistance.

Huang-lian-jie-du-tang (HLJDT), a traditional Chinese medicine, has been shown to improve insulin resistance (IR) induced by inflammation, a key event in the development of metabolic syndrome (MS). The present study aimed to investigate the protective effects of HLJDT on MS and explore the underlying mechanism. MS rats were established with obese-diets and treated with normal saline, aspirin or HLJDT. The myocardial lesions were identified by echocardiogram, transmission electron microscope, and Sirius-red staining. The inflammatory cytokines were measured by ELISA and real-time PCR. The activation of NF-κB, JNK, SOCS3, IRS1 and AKT in the heart was detected by immunohistochemistry and Western blot analysis. Compared with the controls, MS rats developed obvious obesity, hypertension, dyslipidemia, IR, inflammation, and cardiac damage. Moreover, phosphorylated IRS-1 at Ser307 was correlated with the activation of NF-κB, JNK and SOCS3 and the inhibition of AKT in the heart from MS rats. These data suggest that serine phosphorylation of IRS-1 in response to inflammation is mediated, in part, by NF-κB, JNK and SOCS3. Notably, HLJDT inhibited the activation of NF-κB and reduced serine phosphorylation of IRS-1. In summary, HLJDT protects myocardium from IR-mediated injury by inhibiting serine phosphorylation of IRS-1 in MS rats.

Poly(ADP-ribose) polymerase inhibition prevents reactive oxygen species induced inhibition of aldehyde dehydrogenase2 activity.

Lipid peroxidation plays a critical role in cardiovascular diseases. Aldehydes are the major end products of lipid peroxidation and can be metabolized into less reactive chemical species by aldehyde dehydrogenase 2 (ALDH2). However, ALDH2 dehydrogenase activity can be affected by many factors including reactive oxygen species. To elucidate how reactive oxygen species inhibit ALDH2 dehydrogenase activity, we stimulated human aortic endothelial cells (HAECs) with oxidized low-density lipoproteins (ox-LDL) and performed a myocardial ischemia-reperfusion model. Ox-LDL treatment and ischemia-reperfusion injury inhibited ALDH2 dehydrogenase activity. Poly(ADP-ribose) polymerase (PARP) was activated by ox-LDL stimulation and ischemia-reperfusion injury and PARP inhibition partly restored ALDH2 dehydrogenase activity in ox-LDL treated HAECs and ischemia-reperfusion rat hearts. SIRT3 was upregulated by ox-LDL stimulation and ischemia-reperfusion injury and downregulated by PARP inhibition. Using siRNA to knock down SIRT3, we demonstrated that SIRT3 mediated deacetylation decreased ALDH2 dehydrogenase activity and PARP inhibition partly restored ALDH2 dehydrogenase activity through preventing SIRT3 expression and subsequently preserving ALDH2 acetylation.

Simvastatin exerts cardioprotective effects and inhibits the activity of Rho-associated protein kinase in rats with metabolic syndrome.

1. Insulin resistance (IR) is crucially involved in the pathophysiology of metabolic syndrome (MS). The aim of the present study was to investigate the effects of simvastatin on IR in rats with MS. 2. A rat model of MS was established and myocardial damage was examined by transmission electron microscopy. Twenty-two MS rats were divided into two groups of 11 rats each: (i) an MS group; and (ii) a simvastatin-treated MS. Ten Wistar rats were used as controls. The phosphorylation of myosin phosphatase target subunit 1 (MYPT-1), insulin receptor substrate 1 (IRS-1) and Akt were analysed by immunohistochemistry and western blotting. 3. Insulin resistance-induced MS was associated with a significant increase in Rho kinase (ROCK) activity and inhibition of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway. Decreased levels of phosphorylated (p-) MYPT-1 and p-IRS-1 (Ser³°7) and increased levels of p-Akt were found in hearts from the MS + simvastatin compared with the MS group. These results suggest that simvastatin reduces ROCK activity and increases Akt activity. 4. Simvastatin exerts cardioprotective effects and improves IR, which can be attributed, at least in part, to the inhibition of ROCK and activation of PI3-K/Akt.

Myocardial remodeling in rats with metabolic syndrome: role of Rho-kinase mediated insulin resistance.

Insulin resistance (IR) plays a critical role in metabolic syndrome (MS). Previous studies have demonstrated that activated ROCK is increased in MS patients. However, the effect of Rho-kinase (ROCK) on IR has not been definitely determined. Thus, the aims of the present study were to determine whether ROCK activation induces IR or affects myocardial structure and function, as well as the possible mechanisms underlying this process. Wistar rats fed high fat, high glucose and high salt diet sewed as model of MS and we used transmission electron microscopy, echocardiogram technology, and terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling staining to identify any myocardial damage. The protein levels of MYPT-1 (characteristic of ROCK activation), IRS-1 and AKT were analyzed by immunohistochemistry and Western blotting. In hearts from MS rats, we found increased protein levels of phospho-MYPT-1 and phospho-IRS-1 (Ser307) and decreased phospho-AKT compared to levels in normal rats. In conclusion, the results suggest that ROCK-mediated IR is involved in the development of myocardial impairments in MS rats and that this effect is mediated probably via the IRS-1/PI3-kinase/AKT pathway.