Sachiko Bando

Elevated concentrations of pentraxin 3 are associated with coronary plaque vulnerability

BACKGROUND Inflammation is a critical contributing factor to the development and progression of atherosclerosis. Pentraxin 3 (PTX3) is produced abundantly in atherosclerotic lesions while C-reactive protein (CRP) is mainly produced in the liver. In this study, we investigated whether plasma levels of PTX3 might be a sensitive marker both for the severity of coronary artery disease and vulnerable plaques. Next, we determined whether assays for inflammatory molecules can be used to monitor the therapeutic effects of telmisartan on stabilization of vulnerable atherosclerotic plaques. METHODS AND RESULTS We measured PTX3 concentrations in the peripheral and coronary sinus plasma of 40 patients with angina pectoris (AP) and 20 control subjects. Next, in 28 patients with AP, we determined the correlation between levels of inflammatory molecules and the computed tomography (CT) density of plaques as a quantitative index of plaque vulnerability. There was no significant difference in peripheral plasma PTX3 concentrations between patients with AP and control subjects, while coronary sinus plasma PTX3 concentrations were significantly higher in AP patients than control subjects. The concentrations of PTX3 in coronary sinus and peripheral plasma correlated with Gensini scores as an index of severity of coronary atherosclerosis. Interestingly, there was a significantly negative correlation between plasma PTX3 concentrations and CT density (r=-0.67, p<0.01). On the other hand, CT density did not correlate with the peripheral plasma concentrations of monocyte chemoattractant protein-1 (MCP-1) or high-sensitivity CRP (hsCRP). Furthermore, telmisartan treatment for 6 months decreased plasma concentrations of PTX3 but not those of MCP-1 or hsCRP in 12 patients with essential hypertension. Multivariate regression analysis revealed that changes in PTX3 levels were independent of blood pressure changes. CONCLUSIONS PTX3 is likely more specific than hsCRP as an indicator of coronary plaque vulnerability that could lead to plaque rupture.

Expression of NLRP3 in subcutaneous adipose tissue is associated with coronary atherosclerosis

OBJECTIVES The promotion of adipose tissue inflammation by lifestyle-related diseases such as obesity and diabetes accelerates atherogenesis; however, the underlying mechanisms remain incompletely understood. Nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome contributes to chronic inflammation in adipose tissue. Here, we investigated the link between NLRP3 expression in subcutaneous adipose tissue (SAT) and the severity of coronary atherosclerosis. METHODS AND RESULTS SAT was obtained from 72 patients who underwent heart device implantation and coronary angiography. Expression of NLRP3 inflammasome-related molecules (NLRP3, IL-1β and IL-18) in SAT were evaluated by quantitative RT-PCR. Laboratory markers related to lifestyle-related diseases were measured. Patients with obesity, dyslipidemia (P < 0.05, respectively), diabetes or hyperuricemia (P < 0.01, respectively) had significantly higher expression of NLRP3. Multivariate analysis demonstrated that body mass index and serum level of uric acid were predictors of NLRP3 expression in SAT. The expression of NLRP3 in SAT correlated negatively with serum adiponectin level (r = -0.23, P < 0.05). Patients with coronary artery disease showed higher NLRP3 expression than patients without significant stenosis (P < 0.01). Furthermore, the expression of NLRP3 in SAT correlated positively with the severity of coronary atherosclerosis as determined by Gensini score (r = 0.47, P < 0.0001) or SYNTAX score (r = 0.55, P < 0.0001). Multiple regression analysis revealed that the expression of NLRP3 in SAT remains as an independent predictors for the severity of coronary atherosclerosis. CONCLUSIONS The expression of NLRP3 in SAT, which is affected by lifestyle-related diseases, is associated with the severity of coronary atherosclerosis. Our results suggest that NLRP3 inflammasome in SAT may have a role in atherogenesis.

Plasma microRNA-100 is associated with coronary plaque vulnerability.

BACKGROUND Although numerous studies have reported altered plasma levels of various microRNAs (miRNAs) in patients with cardiovascular disease, there are no data on the relationship between plasma miRNAs and vulnerable coronary plaque. In this study, we investigated whether plasma miRNAs might be a sensitive marker of coronary plaque vulnerability. METHODS AND RESULTS Integrated backscatter intravascular ultrasound (IB-IVUS) was performed in 32 consecutive patients with angina pectoris who underwent percutaneous coronary intervention. Three-dimensional analysis of IB-IVUS was performed to determine the percentage of lipid volume (%LV) and fibrous volume (%FV). Circulating miRNAs were measured in EDTA-plasma simultaneously obtained from the aorta and the coronary sinus (CS). Muscle-enriched (miR-133a, miR-208a, miR-499), vascular-enriched (miR-92a, miR-100, miR-126, miR-127, miR-145), and myeloid cell-enriched miRNAs (miR-155, miR-223) were measured. Plasma miR-100 was higher in the CS than in the aorta, but there were no significant differences in the levels of other miRNAs between the aorta and CS. Plasma miR-100 in the aorta was positively correlated with %LV (r=0.48, P<0.01) and negatively correlated with %FV (r=-0.41, P<0.05). Importantly, transcoronary concentration gradient of circulating miR-100 was more strongly correlated with %LV (r=0.53, P<0.01) and %FV (r=-0.56, P<0.01). CONCLUSIONS miR-100 might be released into the coronary circulation from vulnerable coronary plaques. This study provides insights into the role of miRNAs in coronary atherosclerotic disease.

Pentraxin 3 is a local inflammatory marker in atrial fibrillation

Increasing evidence indicates that inflammation contributes to the pathogenesis of atrial fibrillation (AF). Pentraxin 3 (PTX3) is produced abundantly in local inflammatory lesions while C-reactive protein (CRP) is produced mainly in the liver. In this study, we investigated whether a local level of PTX3 might be a sensitive marker for the local inflammation of AF. Blood from the periphery and left atrial appendage (LAA) was sampled from 23 patients with AF undergoing pulmonary vein isolation, and from 10 control subjects with Wolff–Parkinson–White syndrome. We measured peripheral and LAA plasma concentrations of CRP, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and PTX3. Plasma PTX3 concentrations in both locations were higher in patients with AF than in control subjects. PTX3 concentrations were significantly higher in the LAA than the periphery in patients with AF (3.7 ± 1.4 vs 3.3 ± 1.2 ng/ml, P < 0.01), but not in control subjects (2.4 ± 0.5 vs 2.4 ± 0.5 ng/ml, not significant). Patients and controls showed no significant differences in CRP, IL-6, or TNF-α concentrations between the periphery and LAA. Interestingly, there was a significant positive correlation between LAA plasma concentrations of PTX3 and left atrial volume (r = 0.55, P < 0.01). These data demonstrate that Local PTX3 production in the left atrium might reflect the local inflammation of AF.

Ghrelin protects the heart against ischemia-induced arrhythmias by preserving connexin-43 protein

Vagal nerve stimulation has been postulated to confer an antifibrillatory effect. We studied whether ghrelin administration would exert an antiarrhythmic effect via modulation of autonomic nerve activity in rats after acute myocardial ischemia (MI). Male Sprague-Dawley rats were exposed to 30 min of ischemia following ligation of the left coronary artery. Animals were then randomized to receive either ghrelin (n = 26) or saline (n = 26) during the period of coronary ligation. Power spectral analysis of heart-rate variability revealed that the administration of ghrelin increased the high-frequency (HF) power and decreased the low-frequency (LF)/HF ratio. Ventricular tachyarrhythmias were less frequent in rats after MI who received ghrelin in comparison with rats that received saline. Immunoblotting and immunohistochemistry revealed that rats given saline alone during MI exhibited a marked reduction in phosphorylated connexin-43 within the left ventricle, whereas those that received ghrelin displayed only minor reductions in comparison with sham-operated rats. These effects of ghrelin were diminished by the coadministration of atropine or the blockade of vagal afferents. These data demonstrate that the beneficial effect of ghrelin might be mediated by modulation of cardiac autonomic nerve activity.

Relationship between local production of microRNA-328 and atrial substrate remodeling in atrial fibrillation

BACKGROUND The underlying mechanism of atrial substrate remodeling in atrial fibrillation (AF) remains unknown. In this study, we investigated whether local and systemic levels of microRNA (miR) might be associated with the presence of AF and with left atrial (LA) substrate properties. METHODS Blood from the periphery, pulmonary vein (PV), and left atrial appendage (LAA) was sampled from 30 patients with AF undergoing PV isolation, and from 10 control subjects with Wolff-Parkinson-White syndrome and without AF. We measured peripheral, PV, and LAA plasma levels of miR-1, -26, -133a, -328, and -590 by reverse transcription-polymerase chain reaction. LA global contact mapping during sinus rhythm was performed before PV isolation. RESULTS Plasma levels of miR-328 were higher in patients with AF than in control subjects. Plasma miR-328 levels were significantly higher in the LAA than in the periphery and PV in patients with AF, but not in control subjects. Plasma miR-1 levels were also higher in the LAA than in the PV in AF patients. Interestingly, LAA plasma levels of miR-328 showed a positive correlation with the LA voltage zone index (area with voltage <0.5mV divided by total LA surface area) and a weak correlation with LA volume. CONCLUSION Local production of miR-328 in the left atrium may be involved in the process of atrial remodeling in patients with AF.

Plasma brain natriuretic peptide levels are elevated in patients with cancer

Background Natriuretic peptides have been proposed as biomarkers of cardiovascular disease, especially heart failure. Brain natriuretic peptide (BNP) has also been shown to be upregulated at the transcriptional and translational levels by pro-inflammatory cytokines in cardiac myocytes. Although we often measure plasma BNP levels in cancer patients, it remains unknown whether cancer-related inflammation affects the plasma BNP levels. We investigated the relationship between the BNP and human cancers. Methods We retrospectively studied 2,923 patients in whom the plasma BNP levels and serum C-reactive protein (CRP) were measured and echocardiography was performed. Patients with clinically evident heart failure (NYHA II or higher), heart disease requiring medical treatment or surgery, renal dysfunction, and inflammatory disease were excluded. There were 234 patients in the final analysis. Blood sampling was performed before surgery and chemotherapy. In addition, we evaluated the relationship between the inflammation and plasma BNP levels in mouse models of colon cancer. Results Of the 234 patients, 80 were diagnosed with cancer. Both the plasma BNP and serum CRP levels were significantly higher in cancer patients than those without. There were no significant differences in the echocardiographic parameters. There was a significant positive correlation between the plasma BNP and serum CRP levels in cancer patients (r = 0.360, P<0.01) but not in those without. In cancer patients, only the CRP correlated with the BNP independent of the age, creatinine level, hypertension, and body mass index. In addition, in nude mice with subcutaneous colon cancer, the plasma BNP level was elevated compared with that in non-cancer mice, and there was a significant relationship between the plasma BNP and serum levels of the inflammatory markers. Conclusions In cancer patients, as well as colon cancer model mice, the plasma BNP levels were elevated, possibly due to cancer-related inflammation. The effect of cancer on the BNP levels should be considered when using BNP as an indicator of heart failure in cancer patients.

Congenital long QT syndrome with compound mutations in the KCNH2 gene

Congenital long QT syndrome is a genetic disorder encompassing a family of mutations that can lead to aberrant ventricular electrical activity. We report on two brothers with long QT syndrome caused by compound mutations in the KCNH2 gene inherited from parents who had no prolonged QT interval on electrocardiography. The proband had syncope, and his elder brother suffered from ventricular fibrillation. Genetic testing revealed that both brothers had multiple mutations in the KCNH2 gene, including a missense mutation of C1474T (exon 6) as well as a frameshift/nonsense mutation, resulting from the insertion of 25 nucleotides, which caused an altered amino acid sequence beginning at codon 302 and a premature termination codon (i.e., TAG) at codon 339 (exon 4). Family genetic screening found that their father had the same frameshift mutation, and their mother and sister had the same missense mutation, in the KCNH2 gene. However, these other family members were asymptomatic, with normal QT intervals on electrocardiography. These results suggest that compound mutations in the KCNH2 gene inherited independently from the parents made the phenotypes of their sons more severe.

Response Prediction and Influence of Tolvaptan in Chronic Heart Failure Patients Considering the Interaction of the Renin-Angiotensin-Aldosterone System and Arginine Vasopressin

The renin-angiotensin-aldosterone system (RAAS) and arginine vasopressin (AVP) regulate body fluids. Although conventional diuretics have been used for treating heart failure, they activate RAAS and exacerbate renal function. Tolvaptan, a newly developed vasopressin-2 receptor antagonist, elicits aquaresis and improves volume overload in heart failure patients, however, the predictors of tolvaptan effectiveness and the influence on the RAAS and renal function according to tolvaptan therapy are not established. We evaluated 26 chronic heart failure patients receiving therapy with 15 mg/day tolvaptan and examined their laboratory and urinary data before and after tolvaptan therapy. A response to tolvaptan was defined as a body weight decrease by more than 2 kg in a week and a urine volume increase by 500 mL/ day compared with that before tolvaptan administration. Body weight, urine volume, and brain natriuretic peptide levels significantly improved (P < 0.05), without any worsening of renal function represented by serum creatinine, sodium, and potassium. Moreover, no significant changes were observed in the plasma renin activity and plasma aldosterone concentration (PAC). In the responder group, urine osmolality before tolvaptan administration was significantly higher (P < 0.05) but declined significantly after tolvaptan administration (P < 0.05). The AVP/PAC ratio before administration was positively correlated with the efficacy of tolvaptan. Tolvaptan treatment could prevent RAAS activation in chronic heart failure patients. Moreover, monitoring the AVP/PAC ratio may be useful in predicting the tolvaptan response.

Low Serum Levels of Eicosapentaenoic Acid and Docosahexaenoic Acid are Risk Factors for Cardiogenic Syncope in Patients with Brugada Syndrome

The n-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have antiarrhythmic effects, possibly via modulation of the cardiac ion channels. Nevertheless, it is unknown whether low serum levels of n-3 PUFAs are risk factors for ventricular fibrillation in patients with Brugada syndrome (BrS). We retrospectively reviewed data from 62 men with BrS and evaluated their serum levels of EPA and DHA, and the risk factors for sudden cardiac death, including a history of cardiogenic syncope. Nineteen patients had a history of cardiogenic syncope, and their EPA and DHA levels were significantly lower than those of the patients without syncope. Multivariate logistic regression analysis revealed that low EPA and DHA levels were associated with the incidence of syncope. The receiver-operator characteristic curve showed the area under the curves of EPA and DHA for history of syncope were 0.84 and 0.72, respectively. In conclusion, low levels of EPA and DHA are risk factors for cardiogenic syncope in patients with BrS, which suggests that n-3 PUFAs play important roles in preventing ventricular fibrillation in BrS.