Suppression of nitric oxide synthase aggravates non-alcoholic steatohepatitis and atherosclerosis in SHRSP5/Dmcr rat via acceleration of abnormal lipid metabolism

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a progressive subtype of non-alcoholic fatty liver disease (NAFLD) that is closely related to cardiovascular disease (CVD). Nitric oxide (NO) plays a critical role in the control of various biological processes. Dysfunction of the NO signaling pathway is associated with various diseases such as atherosclerosis, vascular inflammatory disease, and diabetes. Recently, it has been reported that NO is related to lipid and cholesterol metabolism. Chronic NO synthase (NOS) inhibition accelerates NAFLD by increasing hepatic lipid deposition. However, the detailed relationship between NO and abnormal lipid and cholesterol metabolism in NAFLD/NASH has not been completely explained. We aimed to determine the effects of NOS inhibition by N omega-nitro-L-arginine methyl ester hydrochloride (L-NAME), a NOS inhibitor, on NASH and CVD via lipid and cholesterol metabolism.

METHODS

Stroke-prone spontaneously hypertensive rats were fed a high-fat and high-cholesterol diet for 8 weeks and administered L-NAME for the last 2 weeks. Following blood and tissue sampling, biochemical analysis, histopathological staining, quantitative RT-PCR analysis, and western blotting were performed.

RESULTS

L-NAME markedly increased hepatic triglyceride (TG) and cholesterol levels by promoting TG synthesis and cholesterol absorption from the diet. L-NAME increased the mRNA levels of inflammatory markers and fibrotic areas in the liver. Cholesterol secretion from the liver was promoted in rats administered L-NAME, which increased serum cholesterol. L-NAME significantly increased the level of oxidative stress marker and lipid deposition in the arteries.

CONCLUSIONS

NOS inhibition simultaneously aggravates NASH and atherosclerosis via hepatic lipid and cholesterol metabolism.

Lavender Essential Oil and Its Main Constituents Inhibit the Expression of TNF-α-induced Cell Adhesion Molecules in Endothelial Cells

Lavender essential oil (Lvn) has anti-inflammatory effects in an ovalbumin-sensitized murine model of asthma, and inhibits inflammatory cell infiltration into the lungs. The anti-inflammatory effects of Lvn on cell adhesion molecules are not clear. Here we evaluated the effects of Lvn and its main constituents, linalyl acetate (LA) and linalool (LO), on the expression of tumor necrosis factor-alpha (TNF-α)-induced cell adhesion molecules in murine brain endothelial bEnd.3 cells and human umbilical vein endothelial cells (HUVECs). The bEnd.3 cells were treated with Lvn, LA, or LO and subsequently stimulated with TNF-α. The mRNA expression levels of cell adhesion molecules were detected using RT-PCR. E-selectin and P-selectin protein and phosphorylated-NF-κB p65 were detected by western blotting. The effects of Lvn on HUVECs were measured by RT-PCR. In bEnd.3 cells, Lvn and LA suppressed TNF-α-induced E-selectin, P-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and phosphorylated-NF-κB p65 in the nucleus; LO did not suppress P-selectin or phosphorylated-NF-κB p65. Lvn inhibited TNF-α-induced E-selectin mRNA in HUVECs. These results indicate that Lvn and LA inhibit TNF-α-induced cell adhesion molecules in endothelial cells through the suppression of NF-κB activation. Consequently, Lvn or other essential oils including LA may be useful as alternative anti-inflammatory medicines.

A High-Fat and High-Cholesterol Diet Induces Cardiac Fibrosis, Vascular Endothelial, and Left Ventricular Diastolic Dysfunction in SHRSP5/Dmcr Rats

AIM

Non-alcoholic steatohepatitis (NASH) increases cardiovascular risk regardless of risk factors in metabolic syndrome. However, the intermediary factors between NASH and vascular disease are still unknown because a suitable animal model has never been established. The stroke-prone (SP) spontaneously hypertensive rat, SHRSP5/Dmcr, simultaneously develops hypertension, acute arterial lipid deposits in mesenteric arteries, and NASH when feed with a high-fat and high-cholesterol (HFC) diet. We investigated whether SHRSP5/Dmcr affected with NASH aggravates the cardiac or vascular dysfunction.

METHOD

Wister Kyoto and SHRSP5/Dmcr rats were divided into 4 groups of 5 rats each, and fed with a SP or HFC diet. After 8 weeks of HFC or SP diet feeding, glucose and insulin resistance, echocardiography, blood biochemistry, histopathological staining, and endothelial function in aorta were evaluated.

RESULTS

We demonstrate that SHRSP5/Dmcr rats fed with a HFC diet presented with cardiac and vascular dysfunction caused by cardiac fibrosis, endothelial dysfunction, and left ventricular diastolic dysfunction, in association with NASH and hypertension. These cardiac and vascular dysfunctions were aggravated and not associated with the presence of hypertension, glucose metabolism disorder, and/or obesity.

CONCLUSIONS

SHRSP5/Dmcr rats may be a suitable animal model for elucidating the organ interaction between NASH and cardiac or vascular dysfunction.

QT Dispersion Measured by Automatic Computerized 12-Lead Electrocardiography Contributes Significantly to Detection of Left Ventricular Hypertrophy in Japanese Patients

This study assessed the diagnostic value of QT dispersion for left ventricular hypertrophy (LVH) as determined by echocardiography. The QT and QRS interval parameters were determined automatically using computerized 12-lead electrocardiography in 153 Japanese outpatients. Corrected QT dispersion (QTcD) and maximal QRS duration (MaxQRS) were significantly correlated with left ventricular mass index. The sum of QTcD and MaxQRS showed the highest correlation with left ventricular mass index among QT and QRS interval parameters and their combinations. The cut-off points for LVH discrimination in this study were different to those reported in Western, mainly Caucasian, populations, suggesting the need for ethnicity-specific LVH detection criteria. A scoring system derived from multiple logistic regression analysis, employing a combination of QTcD, QRS time–voltage product and ST-T change, showed a specificity of 86.3%. It was concluded that QTcD, in addition to QRS time–voltage product and ST-T change, improved the detection of LVH.

Association of serum levels of arachidonic acid and eicosapentaenoic acid with prevalence of major adverse cardiac events after acute myocardial infarction

We studied the association of serum levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA) with the prevalence of major adverse cardiac events (MACE) after acute myocardial infarction (AMI). We measured serum AA and EPA on admission in 146 consecutive AMI patients. The primary clinical endpoint was occurrence of MACE, defined as cardiac death, occurrence of heart failure, reinfarction, recurrent angina pectoris, and requirement of coronary intervention. Common logarithmic transformed serum levels of AA (logAA) and EPA (logEPA) were used in the analyses. The optimum cutoff point of each fatty acid used to distribute patients into two groups for Kaplan-Meier analysis was determined by receiver operating characteristic curves analysis. MACE occurred in 40 patients (27.4%). Kaplan-Meier analysis disclosed that the group with a logAA above the cutoff point [145.3 μg/mL (logAA 2.162)] showed a higher prevalence of MACE than those with a logAA below the cutoff point (P < 0.01). Conversely, the prevalence of MACE was significantly higher in the group with a logEPA below the cutoff point [52.3 μg/mL (logEPA 1.719)] compared to the group with a logEPA above it (P < 0.01). Similar to logAA, logAA/logEPA showed significant differences in the MACE-free curve between the two groups (cutoff 1.301, P < 0.001). Cox proportional hazards regression analysis suggested that logAA, logEPA, and logAA/logEPA were independently associated with the prevalence of MACE. Although the present study included a limited number of patients with single-time point measurement, the results suggested an association of logAA, logEPA, and logAA/logEPA with the prevalence of MACE after AMI. The present study warrants further studies involving a large number of patients to confirm that the serum levels of these fatty acids and their ratios are predictors of MACE after AMI.

Filtered QRS duration on signal-averaged electrocardiography correlates with ventricular dyssynchrony assessed by tissue Doppler imaging in patients with reduced ventricular ejection fraction

OBJECTIVES

The relationships between filtered QRS duration and ventricular dyssynchrony were studied.

METHODS

We measured filtered QRS duration on signal-averaged electrocardiography and analyzed tissue Doppler imaging in chronic heart failure patients with ejection fraction less than 50%.

RESULTS

In 64 patients, interventricular and intraventricular dyssynchronies were observed in 25 and 38 patients, respectively. All patients with interventricular dyssynchrony were associated with intraventricular dyssynchrony. Filtered QRS showed 0.82 and 0.78 of the area under the curve (AUC) in the receiver operating characteristic curve (ROC) for the detection of interventricular and intraventricular dyssynchrony, respectively, with 89.7% and 96.2% specificity and 52.0% and 52.6% sensitivity, with cutoff values of 174 and 153 milliseconds. Specificity and sensitivity as well as AUC were lower in the ROC of QRS duration than filtered QRS duration.

CONCLUSION

Filtered QRS duration provided more reliable information to estimate ventricular dyssynchrony in patients with reduced ventricular ejection fraction than QRS duration did.

The 3'-untranslated region of ADAMTS1 regulates its mRNA stability

ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin motifs 1) is an inflammatory-induced gene. We have previously reported that ADAMTS1 was strongly but transiently expressed in the infarcted heart. In this study, we investigated whether a 3'-untranslated region (UTR) affects the mRNA stability of this gene. When stimulated with tissue necrosis factor (TNF)-alpha, the expression level of ADAMTS1 mRNA rapidly increased, but the induction of ADAMTS1 mRNA peaked at 6h after stimulation, after which the expression levels of ADAMTS1 mRNA decreased. The 3'-UTR ADAMTS1 mRNA contains multiple adenine and uridine-rich elements, suggesting that the 3'-UTR may regulate gene stability. The addition of actinomycin D, an RNA synthesis inhibitor, demonstrated the decay of induced ADAMTS1 mRNA by TNF-alpha. Furthermore, a region containing multiple AUUUA motifs within the ADAMTS1 3'-UTR destabilized transfected Enhanced Green Fluorescence Protein (EGFP) mRNA expression. These results demonstrated that the ADAMTS1 3'-UTR may regulate the expression of ADAMTS1 mRNA.

ADAMTS1 is a unique hypoxic early response gene expressed by endothelial cells

ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin motifs 1) is a member of the matrix metalloproteinase family. We have previously reported that ADAMTS1 was strongly expressed in myocardial infarction. In this study, we investigated whether hypoxia induced ADAMTS1 and investigated its regulatory mechanism. In hypoxia, the expression level of ADAMTS1 mRNA and protein rapidly increased in endothelial cells, but not in other cell types. Interestingly, the induction of ADAMTS1 by hypoxia was transient, whereas vascular endothelial growth factor induction by hypoxia in human umbilical vein endothelial cells (HUVEC) increased in a time-dependent manner. CoCl2, a transition metal that mimics hypoxia, induced ADAMTS1 in HUVEC. The phosphatidylinositol 3-kinase inhibitor LY294002 dose-dependently inhibited the increase of ADAMTS1 mRNA expression in hypoxia. We characterized the promoter region of ADAMTS1, and the secreted luciferase assay system demonstrated that hypoxia induced luciferase secretion in the culture medium 4.6-fold in HUVEC. In the promoter region of ADAMTS1, we found at least three putative hypoxia-inducible factor (HIF) binding sites, and the chromatin immunoprecipitation assay revealed HIF-1 binding to HIF binding sites in the promoter region of ADAMTS1 under hypoxia. Recombinant ADAMTS1 protein promoted the migration of HUVEC under hypoxic conditions. In summary, we found that ADAMTS1 is transiently induced by hypoxia in endothelial cells, and its transcription is mediated by HIF-1 binding. Our data indicate that ADAMTS1 is a novel acute hypoxia-inducible gene.

Increased blood pressure levels relative to subjective feelings of intensity of exercise determined with the Borg scale in male patients with hypertension

We examined the hemodynamic responses to exercise and symptoms in 37 male patients with untreated essential hypertension, and compared the findings with those in 32 age-matched healthy male volunteers by performing a graded symptom-limited exercise test using a bicycle ergometer. The subjective feeling of intensity of exercise was determined using the Borg scale. In the relationship between Borg scores and blood pressure (BP), patients with hypertension showed higher systolic BP and diastolic BP relative to the Borg scores than the controls. Consequently, patients with hypertension showed significantly higher systolic BP with Borg scores < or = 3 (subjective symptoms < or = moderately hard) than the controls (177.8 +/- 27.0 vs. 143.7 +/- 17.9 mmHg, p < 0.0001). Similarly, significantly higher diastolic BP with Borg scores < or = 3 was observed in patients with hypertension than in the controls (101.6 +/- 12.0 vs. 82.6 +/- 11.6 mmHg, p < 0.0001). The pulse pressure with Borg scores < or = 3 was also significantly higher in patients with hypertension than in the controls (76.2 +/- 20.6 vs. 61.0 +/- 13.6 mmHg, p < 0.0001). Hypertensive patients showed a decrease in the high-frequency power of heart rate variability at initial low-load exercise. In conclusion, the present study revealed that there was a greater BP response relative to the Borg score in patients with hypertension than in the controls. Autonomic nerve activity may contribute to some extent to these different relations. A determination of the relationship between the subjective feeling of intensity of the exercise and BP levels caused by a given intensity of load is essential before exercise training in patients, at least in males, with hypertension to avoid increasing the risk of cardiovascular events in association with excessive exercise training.

Serum interferon-gamma-inducible protein 10 level was increased in myocardial infarction patients, and negatively correlated with infarct size

OBJECTIVES

We examined the serum levels of interferon-gamma-inducible protein 10 (IP-10), an inflammation-induced chemokine, in acute myocardial infarction (AMI).

DESIGN AND METHODS

The subjects were 33 AMI patients, 20 stable angina pectoris patients (AP) and 20 normal subjects. In AMI patients, blood samples were collected before percutaneous coronary intervention (PCI) and on days 3, 7 and 28.

RESULTS

Patients with AMI showed significantly higher serum IP-10 levels (137.5+/-79.8 pg/mL) than control subjects (91.2+/-40.1 pg/mL) and patients with AP (93.3+/-41.1 pg/mL). The serum IP-10 level before PCI was negatively correlated with infarct size, as indicated by cumulative release of creatine kinase (CK) and peak CK and its isoenzyme CK-MB. Stepwise multiple regression analysis revealed that the serum IP-10 level before PCI was an independent predictor of cumulative CK release.

CONCLUSIONS

The serum IP-10 level was increased in AMI, and a higher level of serum IP-10 before PCI may be informative regarding infarct size.

Use of Plasma B-Type Natriuretic Peptide Level to Identify Asymptomatic Hypertensive Patients with Abnormal Diurnal Blood Pressure Variation Profiles: Nondippers, Extreme Dippers, and Risers

We examined the relationship between plasma B-type natriuretic peptide (BNP) level and diurnal variability pattern of blood pressure (BP). Twenty-four-hour ambulatory BP monitoring was performed in 98 patients with asymptomatic essential hypertension, and the patients were classified into four groups according to their circadian BP variation profiles: dippers (n=29), nondippers (n=36), extreme dippers (n=19), and risers (n=14). Plasma BNP was measured by enzyme immunoassay. Based on the distribution pattern of BNP values, the values were analyzed after logarithmic transformation. Significant differences in plasma BNP levels among the types of circadian BP variations were demonstrated by analysis of variance (p<0.0005). Nondippers and risers showed significantly higher plasma BNP levels (mean [range: -1 SD and +1 SD]: 16.1 [6.3, 41.6] pg/mL and 29.2 [15.9, 53.4] pg/mL, respectively) than dippers (8.4 [3.7, 19.1] pg/mL). The area under the receiver operating characteristics curve for distinguishing patients with abnormal circadian BP variation from those with normal variation was 0.72, indicating that plasma BNP levels were useful for distinguishing between these patients. Specificity of 69% and sensitivity of 72% were obtained with a cut-off value of 10.5 pg/mL (log plasma BNP, 1.02) for distinguishing the abnormal diurnal BP profile group from the normal group. In conclusion, hypertensive patients with abnormal diurnal BP variation patterns (nondippers, extreme dippers, and risers) showed higher plasma BNP levels than those with normal circadian BP variation (dippers). Plasma BNP level is clinically useful for the identification of hypertensive patients who have abnormal circadian BP variability, which increases the risk of cardiovascular events.

Cloning and reporter analysis of human mitochondrial phosphoenolpyruvate carboxykinase gene promoter

Phosphoenolpyruvate carboxykinase (PEPCK) is one of the key regulatory enzymes in gluconeogenesis. In human liver, PEPCK is about equally distributed in both cytosol (PEPCK-1) and mitochondria (PEPCK-2). The human pepck2 gene and cDNA have been reported, but the cloning of the promoter region of the pepck2 gene has not been elucidated yet. We isolated and characterized human genomic P1-artificial chromosome (PAC) clones carrying the human pepck2 gene promoter. The oligocapping method revealed that the transcriptional start point (tsp) of the human pepck2 gene is located at 97 bp upstream of the first adenine residue of the translation start site. We also determined the nucleotide sequence to 1819 bp upstream of tsp. Sequence analysis of this region revealed that it contained several potential regulatory elements, including five GC boxes and three CCAAT boxes. Reporter analysis using transient transfection with firefly luciferase synthetic gene indicated 5' flanking region up to 822 bp, and 317 bp upstream of tsp had transcriptional activity. These results suggest that these regions of the human pepck2 gene play an important role for its expression.

Nafamostat mesilate is an extremely potent inhibitor of human tryptase

Previously, nafamostat mesilate was found to be a potent inhibitor of human tryptase. In present study, we performed a kinetic study to determine its K(i) value for tryptase and compared it with that of gabexate mesilate. Nafamostat mesilate inhibited human tryptase in a competitive manner. The apparent K(i) value was estimated to be 95.3 pM, which was 1000 times lower than that of gabexate mesilate (95.1 nM). These results strongly indicated that nafamostat mesilate is an extremely potent inhibitor of tryptase and suggested that some of its beneficial effects in the treatment of clinical status may be due to tryptase inhibition.

Histidine-rich glycoprotein plus zinc reverses growth inhibition of vascular smooth muscle cells by heparin

Vascular smooth muscle cell (SMC) hyperplasia is known to be an important component in the pathogenesis of arteriosclerosis and restenosis. Although heparin has been well recognized as the representative molecule suppressing SMC growth in vitro, attempts to use heparin as a therapeutic anti-restenosis drug have not favorably influenced the angiographic or clinical outcome after angioplasty in some clinical trials. In this study, we have examined the effect of histidine-rich glycoprotein (HRG), a relatively abundant serum glycoprotein (~100 micrograms/ml in human serum), on the growth inhibition of cultured vascular SMC by heparin. Vascular SMC growth was significantly inhibited by heparin, giving nearly 85% inhibition with 100 micrograms/ml heparin. HRG reversed heparin-induced SMC growth inhibition in a dose dependent manner; 75% restoration of cell growth was observed when 100 micrograms/ml of HRG was co-added with 100 micrograms/ml heparin. Interestingly, micromolar concentrations of the zinc ion (0-10 microM), compatible with concentrations released from activated platelets, were found to enhance the restorative action of HRG. Western blot experiment demonstrated no significant amounts of the HRG moiety in fetal bovine serum, eliminating the possible contribution of contaminant HRG from culture media. These findings indicate that HRG, in combination with the zinc ion, plays a role in modulating the SMC growth response in pathophysiological states and explain the lack of success of heparin as a therapeutic anti-restenosis drug in clinical trials.