Atorvastatin Reduces the Expression of COX-2 mRNA in Peripheral Blood Monocytes from Patients with Acute Myocardial Infarction and Modulates the Early Inflammatory Response

Periplocymarin protects against myocardial fibrosis induced by β-adrenergic activation in mice

Periplocymarin is an effective component of Periplocae Cortex, which was wildly used as an ingredient in Traditional Chinese Medicine. Our group previously reported that periplocymarin exerted cardiotonic role via promoting calcium influx. However, its exact role in the pathogenesis of myocardial fibrosis has not been elucidated yet. The present study was aimed at determining the potential effect and underlying mechanism of periplocymarin in isoproterenol (ISO)-induced myocardial fibrosis. C57BL/6 mice were subcutaneously injected with ISO (5 mg/kg/day) or saline for 1 week. The early-to-atrial wave ratio (E/A ratio) measured by echocardiography revealed that ISO-induced heart stiffness was remarkably reversed by administration of periplocymarin (5 mg/kg/day). Masson trichrome staining exhibited that treatment of periplocymarin reduced the excessive deposition of extracellular matrix (ECM). Further investigations employing real-time PCR and western blot demonstrated that periplocymarin suppressed the expression of fibrosis related genes (Col1a1, Col3a1, Acta2 and Tgfb1) and proteins (Collagen I, Collagen III, α-SMA and TGF-β1) induced by ISO. Metabolomics analysis demonstrated that periplocymarin ameliorated the disorders triggered by ISO and many of the differential metabolic substances were involved in amino acid, glucose and lipid metabolism. Further analysis using network pharmacology revealed that three key genes, namely NOS2, NOS3 and Ptgs2, may be the potential targets of periplocymarin and responsible for the disorders. Validation using heart tissues showed that the mRNA expression of NOS3 was decreased while Ptgs2 was increased upon ISO treatment, which were reversed by periplocymarin. Moreover, the expression of COX-2 (Ptgs2 encoded protein) was consistent with the aspect of Ptgs2 mRNA, while eNOS (NOS3 encoded protein) expression was unchanged. In vitro studies exhibited that periplocymarin exerts anti-fibrotic function via regulating at least eNOS and COX-2 in cardiomyocyte. Taken together, periplocymarin protects against myocardial fibrosis induced by β-adrenergic activation, the potential mechanism was that periplocymarin targeted on, at least eNOS and COX-2, to improve the metabolic processes of cardiomyocyte and thus attenuated the myocardial fibrosis. Our study highlighted that periplocymarin is a potential therapeutic agent for the prevention of myocardial fibrosis.

Chemopreventive effect of omega-3 polyunsaturated fatty acids and atorvastatin in rats with bladder cancer

Bladder cancer remains a huge concern for the medical community because of its incidence and prevalence rates, as well as high percentage of recurrence and progression. Omega-3 polyunsaturated fatty acids and atorvastatin proved anti-inflammatory effects through peroxisome proliferator-activated receptor gamma mechanism. However, their chemopreventive effect still remained to be examined and clarified. In this study, bladder cancer was induced in rats by the chemical carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine. Omega-3 polyunsaturated fatty acids (docosahexaenoic acid and eicosapentaenoic acid: 2:3 w/w; 1200 mg/kg) and/or atorvastatin (6 mg/kg) were given orally daily to rats for eight consecutive weeks concomitantly with N-butyl-N-(4-hydroxybutyl)nitrosamine and continued for further 4 weeks after cessation of N-butyl-N-(4-hydroxybutyl)nitrosamine administration. The histopathological examination of rat bladder revealed the presence of tumors and the absence of apoptotic bodies in sections from N-butyl-N-(4-hydroxybutyl)nitrosamine group, while tumors were absent and apoptotic bodies were clearly observed in sections from rat groups treated with omega-3 polyunsaturated fatty acids, atorvastatin, or both drugs. The study of the molecular mechanisms illustrated downregulation of COX-2 and P53 (mutant) genes and suppression of transforming growth factor beta-1 and the lipid peroxidation product malondialdehyde in serum of rats of the three treated groups. This chemopreventive effect was confirmed by and associated with lower level of bladder tumor antigen in urine. However, the combined treatment with both drugs exhibited the major protective effect and nearly corrected the dyslipidemia that has been induced by N-butyl-N-(4-hydroxybutyl)nitrosamine. Collectively, omega-3 polyunsaturated fatty acids and atorvastatin, besides having anti-inflammatory properties, proved a chemopreventive effect against bladder cancer, which nominates them to be used as adjuvant therapy with other chemotherapeutics.

Atorvastatin attenuates plaque vulnerability by downregulation of EMMPRIN expression via COX-2/PGE2 pathway

Extracellular matrix metalloproteinase inducer (EMMPRIN) reportedly has a key regulatory role in matrix metalloproteinase (MMP) activities and the progression of atherosclerosis. Statins, which are anti-atherosclerotic pharmacological agents, are widely applied in clinical settings. The aim of the present study was to investigate the pharmaceutical effect of atorvastatin on EMMPRIN expression in atherosclerotic plaques. An atherosclerotic mouse model was established using apoliprotein E-deficient (ApoE^−/−) mice raised on a high-fat diet. Additionally, a low (5 mg/kg/day) or high dosage (10 mg/kg/day) of atorvastatin suspension was administered orally for eight weeks, beginning on week 7 or 11 respectively. The effects of atorvastatin on atherosclerotic plaque formation and EMMPRIN expression were subsequently determined. The THP-1 cell line was used to investigate the effect of atorvastatin on EMMPRIN expression in vitro. The results demonstrated that the high-fat diet led to vulnerable plaques (VPs) and increased EMMPRIN expression in VPs in ApoE^−/− mice. Atorvastatin treatment decreased EMMPRIN expression in the aortas and plaques of ApoE^−/− mice. In vitro, oxidized low-density lipoprotein (ox-LDL) induced the expression of cyclooxygenase-2 (COX-2) and EMMPRIN in THP-1 macrophages, and atorvastatin inhibited ox-LDL-induced expression of PGE2, EMMPRIN and COX-2 in THP-1 macrophages. Therefore, the present data indicated that atorvastatin treatment reduces the vulnerability of atherosclerotic plaques and expression of EMMPRIN, and that the inhibitory effect of atorvastatin on EMMPRIN may occur via the COX-2/PGE2 signaling pathway in macrophages.

Cryptotanshinone attenuates cardiac fibrosis via downregulation of COX-2, NOX-2, and NOX-4

Cryptotanshinone (CTS), a bioactive constituent extracted from a Chinese traditional herb Danshen (Salvia miltiorrhiza), demonstrates multiple protective effects against cardiovascular diseases. The present study was designed to explore the effects of CTS in vitro by cultured adult rat cardiac fibroblasts stimulated with angiotensin II (Ang II) and in vivo by rats with acute myocardial infarction. Our data showed that in cardiac fibroblasts, CTS attenuated Ang II-induced upregulation of fibronectin, connective tissue growth factor, cyclooxygenase-2, and normalized Ang II-induced upregulation of extracellular signal-regulated kinases 1/2 (ERK1/2). Meanwhile, CTS depressed the Ang II-stimulated upregulation of NAD(P)H oxidase 2 and 4 (NOX-2 and NOX-4) and reactive oxygen species production. Similar results were observed in acute myocardial infarction rats with oral administration of CTS, which relieved the pathological changes accompanying myocardial infarction. In conclusion, CTS may exert antifibrotic effects in vitro by inhibiting Ang II-induced extracellular signal-regulated kinases 1/2 phosphorylation and the expression of cyclooxygenase-2, NOX-2, and NOX-4, and also improved the pathological changes and relieved cardiac fibrosis in vivo.

Homocysteine induces COX-2 expression in macrophages through ROS generated by NMDA receptor-calcium signaling pathways

Homocysteine (Hcy) at elevated levels is a putative risk factor for many cardiovascular disorders including atherosclerosis. In the present study, we investigated the effect of Hcy on the expression of cyclooxygenase (COX)-2 in murine macrophages and the mechanisms involved. Hcy increased the expression of COX-2 mRNA and protein in dose- and time-dependent manners, but did not affect COX-1 expression. Hcy-induced COX-2 expression was attenuated not only by the calcium chelators, EGTA and BAPTA-AM, but also by an antioxidant, N-acetylcysteine. Calcium chelators also attenuated Hcy-induced reactive oxygen species (ROS) production in macrophages, indicating that Hcy-induced COX-2 expression might be mediated through ROS generated by calcium-dependent signaling pathways. In another series of experiments, Hcy increased the intracellular concentration of calcium in a dose-dependent manner, which was attenuated by MK-801, an N-methyl-D-aspartate (NMDA) receptor inhibitor, but not by bicuculline, a gamma-aminobutyric acid receptor inhibitor. Molecular inhibition of NMDA receptor using small interfering RNA also attenuated Hcy-induced increases in intracellular calcium. Furthermore, both ROS production and Hcy-induced COX-2 expression were also inhibited by MK-801 as well as by molecular inhibition of NMDA receptor. Taken together, these findings suggest that Hcy enhances COX-2 expression in murine macrophages by ROS generated via NMDA receptor-mediated calcium signaling pathways.

Celecoxib, a selective cyclooxygenase-2 inhibitor, lowers plasma cholesterol and attenuates hepatic lipid peroxidation during carbon-tetrachloride-associated hepatotoxicity in rats

Cyclooxygenase-2 (COX-2) expression and prostaglandin production are suggested to play important, complex roles in the pathogenesis of various liver diseases. Studies on the effects of COX-2 inhibitors on the progression of liver fibrosis present controversial results, and the proposed therapeutic potential of these agents in chronic liver disease is predicated largely on their effectiveness in modulating hepatic stellate cell activation in vitro. This study investigated the modulatory effect of celecoxib, a selective COX-2 inhibitor, in CCl(4)-mediated hepatotoxicity in rats. Thirty Wistar albino rats, weighing 120-180 g, were assigned into five groups of 6 rats/group. Groups 1 and 2 received saline (10 mL/kg) and CCl(4) (80 mg/kg), respectively. Group 3 was given celecoxib (5.7 mg/kg), whereas groups 4 and 5 were pretreated with 2.9 and 5.7 mg/kg/day of celecoxib, respectively, 1 hour before CCl(4) treatment. Plasma aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activities increased significantly by 118.5, 150.0, and 51.3%, respectively, with an accompanying decrease (P < 0.05) in total protein and albumin after CCl(4) treatment. Hepatotoxicity was associated with a significant increase in plasma cholesterol, hepatic lipid peroxidation (LPO), and severe hepatic necrosis with marked fatty and cellular (i.e., mononuclear cells) infiltration. Although celecoxib neither reduced CCl(4)-induced increases in marker enzymes of hepatotoxicity nor significantly attenuated hepatic necrosis, it, however, was effective in reducing elevated cholesterol by 16.5 and 20.8% and LPO by 12.9 and 35.5% at 2.9 and 5.7 mg/kg, respectively. Data suggest that COX-2 inhibitors may be effective in controlling hypercholesterolemia and peroxidative changes associated with liver injury.

C-reactive protein and venous thromboembolism: causal or casual association?

The plasma concentration of C-reactive protein (CRP), the first acute-phase protein to be identified, increases dramatically following tissue injury or inflammation. Although the physiological role of CRP is still not fully known, it has been suggested that concentrations might increase as part of the acute-phase response for facilitating non-specific immune functions, defense against bacterial pathogens, clearance of apoptotic and necrotic cells to prevent immunization against autoantigens and acceleration of the repair process. In agreement with the evidence that inflammation plays a pivotal role in the pathogenesis of atherosclerosis, CRP concentrations have been associated with cardiovascular disease, and measurement of CRP has therefore been proposed as a valuable aid to predict and stratify the risk of myocardial infarction and stroke. Recently, some clinical and biological evidence in support of the hypothesis that CRP might be also involved in the onset of venous thrombosis have emerged. Native and monomeric CRP exert several prothrombotic activities, including activation of blood coagulation, impairment of the endogenous fibrinolytic capacity, and stimulation or enhancement of platelet adhesiveness and responsiveness. Epidemiological investigations have also shown that CRP concentrations are associated with increased risk of venous thromboembolism and, even more interestingly, that statins might be effective in reducing the risk of this pathology. Although there is increasing emphasis that CRP might not only be a marker but also an active player in the development of venous thrombosis, further evidence is needed to establish which event comes first--thrombosis or inflammation.

In vitro effects of atorvastatin on lipopolysaccharide-induced gene expression in endometriotic stromal cells

OBJECTIVE

To investigate the in vitro effects of atorvastatin on lipopolysaccharide (LPS)-induced gene expression in endometrial-endometriotic stromal cells.

DESIGN

In vitro experimental study using flow cytometry, ELISA, semiquantitative reverse transcriptase polymerase chain reaction, and Western blot.

SETTING

Postgraduate Institute of Medical Education and Research.

PATIENT(S)

Twenty-five women undergoing laparoscopy (n = 10) and laparotomy (n = 15).

INTERVENTION(S)

Endometriotic cyst wall (group I) and endometrial biopsy (group II) collection.

MAIN OUTCOME MEASURE(S)

The endometrial-endometriotic stromal cells were isolated from ectopic (group I) and eutopic (group II) endometrium by established methods, cultured, and stimulated with LPS (1 μg/mL), followed by atorvastatin treatment in a time- and dose-dependent manner to investigate the effects of LPS on proliferation (Ki-67) and expression of cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), receptor for advanced glycation end products (RAGE), extracellular newly identified RAGE binding protein (EN-RAGE), peroxisome proliferator activated receptor-γ (PPAR-γ), and liver X receptor-α (LXR-α) genes in endometrial-endometriotic stromal cells and on levels of insulin-like growth factor binding protein-1 (IGFBP-1) and 17β-E(2) in endometrial-endometriotic stromal cell culture supernatant.

RESULT(S)

Significant inhibition of Ki-67 and LPS-induced expression of inflammatory and angiogenic genes (COX-2, VEGF, RAGE, and EN-RAGE) was observed in atorvastatin-treated endometrial-endometriotic stromal cells. In contrast, a significant dose- and time-dependent increase in expression of anti-inflammatory genes (PPAR-γ and LXR-α) and levels of IGFBP-1 was observed after atorvastatin treatment in both the groups. However, atorvastatin treatment had no effect on 17β-E(2) levels in endometrial/endometriotic stromal cell culture supernatant.

CONCLUSION(S)

The data of the present study provide new insights for the implication of atorvastatin treatment for endometriosis in humans.

Induction of hepatic cyclooxygenase-2 by hyperhomocysteinemia via nuclear factor-κB activation

Hyperhomocysteinemia, an elevation of blood homocysteine (Hcy), is a metabolic disorder associated with dysfunction of multiple organs. Apart from endothelial dysfunction, Hcy can cause hepatic lipid accumulation and liver injury. However, the mechanism responsible for Hcy-induced liver injury is poorly understood. The aim of this study was to investigate the regulation of cyclooxygenase-2 (COX-2), a proinflammatory factor, expression in the liver during the initial phase of hyperhomocysteinemia. Sprague-Dawley rats were fed a high-methionine diet for 1 or 4 wk. Serum and liver concentrations of Hcy were significantly elevated after 1 or 4 wk of dietary treatment. COX-2 mRNA and protein levels were significantly elevated in the liver of hyperhomocysteinemic rats. The induction of COX-2 expression was more prominent in 1-wk hyperhomocysteinemic rats than that in the 4-wk group. EMSA revealed an activation of NF-κB in the same liver tissue in which COX-2 was induced. Administration of a NF-κB inhibitor to hyperhomocysteinemic rats effectively abolished hepatic COX-2 expression, inhibited the formation of inflammatory foci, and improved liver function. Further investigation revealed that oxidative stress due to increased superoxide generation was responsible for increased phosphorylation and degradation of IκBα leading to NF-κB activation in the liver. Administration of 4-hydroxy-tetramethyl-piperidine-1-oxyl, an SOD mimetic, to hyperhomocysteinemic rats not only inhibited NF-κB activation but also prevented hepatic COX-2 induction and improved liver function. These results suggest that hyperhomocysteinemia-induced COX-2 expression is mediated via NF-κB activation. Increased oxidative stress and inflammatory response may contribute to liver injury associated with hyperhomocysteinemia.

The impact of platelet function or C-reactive protein, on cardiovascular events after an acute myocardial infarction

Background

Recurrent cardiovascular events following acute myocardial infarction (AMI) are common. The purpose of this study was to evaluate the impact of platelet aggregation, PFA-100 closure times and peak C-reactive protein (CRP), respectively, on the occurrence of death, myocardial infarction and ischemic cerebral events after an AMI. Furthermore, to examine the relationship between the platelet function tests and peak CRP.

Methods

Three hundred and thirty-four patients with AMI were included in the study. Platelet aggregation was analyzed by an aggregometer using laser light (PA-200). The state of high residual platelet reactivity was defined as normal closure times (PFA-100) during treatment with aspirin.

Results

The fourth quartile of peak CRP was associated with poorer outcome as compared to the first quartile in a multivariate Cox-regression analysis, with a hazard ratio of 2.0 (95% CI 1.1–3.7) for the occurrence of death, myocardial infarction and ischemic cerebral events. The fourth quartile of peak CRP (>64.6 mg/l) was associated with platelet aggregation (p < 0.001, adjusted R² = 0.13) and high residual platelet reactivity, in a multivariate model, with an odds ratio of 2.9 (CI 95% 1.3–6.8), as compared to the first quartile. Neither the highest quartile of platelet aggregation nor the state of high residual platelet reactivity predicted new cardiovascular events.

Conclusion

In patients with myocardial infarction, measured peak CRP is associated with new cardiovascular events. Despite an association with peak CRP neither more pronounced platelet aggregation nor PFA-100 closure times independently predict new cardiovascular events.