Tomofumi Misaka

Serum tenascin-C level is associated with coronary plaque rupture in patients with acute coronary syndrome

Tenascin-C, a large oligometric glycoprotein of the extracellular matrix, increases the expression of matrix metalloproteinases that lead to plaque instability and rupture, resulting in acute coronary syndrome (ACS). We hypothesized that a high serum tenascin-C level is associated with plaque rupture in patients with ACS. Fifty-two consecutive ACS patients who underwent emergency percutaneous coronary intervention (PCI) and, as a control, 66 consecutive patients with stable angina pectoris (SAP) were enrolled in this study. Blood samples were obtained from the ascending aorta just prior to the PCI procedures. After coronary guide-wire crossing, intravascular ultrasonography (IVUS) was performed for assessment of plaque characterization. Based on the IVUS findings, ACS patients were assigned to two groups according to whether there was ruptured plaque (ruptured ACS group) or not (nonruptured ACS group). There were 23 patients in the ruptured group and 29 patients in the nonruptured group. Clinical characteristics and IVUS measurements did not differ between the two groups. Tenascin-C levels were significantly higher in the ruptured ACS group than in the SAP group, whereas there was no significant difference between the nonruptured ACS and SAP groups. Importantly, in the ruptured ACS group, tenascin-C levels were significantly higher than in the nonruptured ACS group (71.9 ± 34.9 vs 50.5 ± 20.5 ng/ml, P < 0.005). Our data demonstrate that tenascin-C level is associated with pathologic conditions in ACS, especially the presence of ruptured plaque.

Deficiency of senescence marker protein 30 exacerbates angiotensin II-induced cardiac remodelling

AIMS Ageing is an important risk factor of cardiovascular diseases including heart failure. Senescence marker protein 30 (SMP30), which was originally identified as an important ageing marker protein, is assumed to act as a novel anti-ageing factor in various organs. However, the role of SMP30 in the heart has not been previously explored. In this study, our aim was to elucidate the functional role of SMP30 on cardiac remodelling. METHODS AND RESULTS SMP30 knockout (KO) mice and wild-type (WT) mice were subjected to continuous angiotensin II (Ang II) infusion. After 14 days, the extent of cardiac hypertrophy and myocardial fibrosis was significantly higher in SMP30-KO mice than in WT mice. Echocardiography revealed that SMP30-KO mice had more severely depressed systolic and diastolic function with left ventricular dilatation compared with WT mice. Generation of reactive oxygen species related with activation of nicotinamide adenine dinucleotide phosphate-oxidase was greater in SMP30-KO mice than in WT mice. The number of deoxynucleotidyl transferase-mediated dUTP nick end-labelling positive nuclei was markedly increased in SMP30-KO mice with activation of caspase-3, increases in the Bax to Bcl-2 ratio and phosphorylation of c-Jun N-terminal kinase compared with WT mice. Furthermore, the number of senescence-associated β-galactosidase-positive cells was significantly increased via up-regulation of p21 gene expression in SMP30-KO mice compared with WT mice. CONCLUSION This study demonstrated the first evidence that deficiency of SMP30 exacerbates Ang II-induced cardiac hypertrophy, dysfunction, and remodelling, suggesting that SMP30 has a cardio-protective role in cardiac remodelling with anti-oxidative and anti-apoptotic effects in response to Ang II.

Association between levels of anti-angiogenic isoform of vascular endothelial growth factor A and pulmonary hypertension

BACKGROUNDS Pulmonary hypertension (PH) is characterized by elevated pulmonary arterial pressure due to vasoconstriction and remodeling of the pulmonary microvasculature. Vascular endothelial growth factor (VEGF) is a key contributor for angiogenesis and vasculogenesis. VEGF165b is recently identified as an anti-angiogenic splicing variant of VEGF. The aim of this study was to examine the association between circulating levels of VEGF165b in PH patients under consideration with classifications of PH. METHODS AND RESULTS We measured plasma levels of VEGF165b in the PH group (pulmonary artery hypertension [PAH], n=26; chronic thromboembolic pulmonary hypertension [CTEPH], n=13) and control group (n=30). Circulating levels of VEGF165b were higher in PH group than controls (97.1 vs. 53.3pg/ml, P<0.01). The multiple regression analysis demonstrated that the independent factor to determine the plasma levels of VEGF165b was the presence of PH (P=0.04). Next, we focused on differences in VEGF165b levels and classifications of PH. Plasma VEGF165b level was higher only in idiopathic PAH (n=9) than in control (137.1 vs. 53.3pg/ml, P<0.01), but not in PH related to collagen disease (n=7), congenital heart disease (n=10) and CTEPH (n=13). CONCLUSIONS We demonstrated associations between circulating levels of VEGF165b and classifications of PH. VEGF165b, anti-angiogenic isoform, might contribute to the pathophysiology in PH, especially in idiopathic PAH. The level of plasma VEGF165b might be a novel marker that reflects the pathological conditions in patients with PH.

Long-term clinical outcomes after deferral of percutaneous coronary intervention of intermediate coronary stenoses based on coronary pressure-derived fractional flow reserve.

Coronary pressure-derived fractional flow reserve (FFR) has been used to evaluate functional severity of coronary artery stenoses. The cut-off point of 0.75 was considered to be the indication for percutaneous coronary intervention (PCI). In this study, we examined the prognosis of patients in whom PCI was deferred because the lesion was not significant by FFR (≥0.75). We measured FFR of 44 patients (50 lesions with angiographically intermediate stenoses by pressure wire between 2002 and 2009. Out of 44 patients (50 lesions), functionally non-significant stenoses with FFR≥0.75 were 29 patients (33 lesions) and PCI was deferred. In the remaining 15 patients (17 lesions), FFR was <0.75 and PCI was performed. Patients were followed up for an average period of 53 months with endpoints of major adverse cardiac events (MACE; cardiac death, acute coronary syndrome, PCI, and coronary artery bypass grafting). The rate of MACE was 2/29 (6.9%) in patients with FFR≥0.75 and 2/15 (13.3%) in those with FFR<0.75, and it was not statistically different between the two groups. Since long-term clinical outcomes after deferral of PCI of intermediate coronary stenoses based on FFR were excellent (annual event rate 1.6%/year), FFR is a useful index to judge the indication of PCI and risk-stratify patients for MACE.

Epicardial Adipose Tissue Reflects the Presence of Coronary Artery Disease: Comparison with Abdominal Visceral Adipose Tissue

Accumulation of visceral adipose tissue is associated with a risk of coronary artery disease (CAD). The aim of this study was to examine whether different types of adipose tissue depot may play differential roles in the progression of CAD. Consecutive 174 patients who underwent both computed tomography (CT) and echocardiography were analyzed. Cardiac and abdominal CT scans were performed to measure epicardial and abdominal visceral adipose tissue (EAT and abdominal VAT, resp.). Out of 174 patients, 109 and 113 patients, respectively, presented coronary calcification (CC) and coronary atheromatous plaque (CP). The EAT and abdominal VAT areas were larger in patients with CP compared to those without it. Interestingly, the EAT area was larger in patients with CC compared to those without CC, whereas no difference was observed in the abdominal VAT area between patients with CC and those without. Multivariable logistic regression analysis revealed that the presence of echocardiographic EAT was an independent predictor of CP and CC, but the abdominal VAT area was not. These results suggest that EAT and abdominal VAT may play differential pathological roles in CAD. Given the importance of CC and CP, we should consider the precise assessment of CAD when echocardiographic EAT is detected.

Coronary Artery Spasm Related to Thiol Oxidation and Senescence Marker Protein-30 in Aging

BACKGROUND Senescence marker protein-30 (SMP30) decreases with aging, and SMP30 knockout (KO) mice show a short life with increased oxidant stress. AIMS We assessed the effect of oxidant stress with SMP30 deficiency in coronary artery spasm and clarify its underlying mechanisms. RESULTS We measured vascular responses to acetylcholine (ACh) and sodium nitroprusside (SNP) of isolated coronary arteries from SMP30 KO and wild-type (WT) mice. In SMP30 KO mice, ACh-induced vasoconstriction occurred, which was changed to vasodilation by dithiothreitol (DTT), a thiol-reducing agent. However, Nω-nitro-L-arginine-methyl ester, nitric oxide (NO) synthase inhibitor, or tetrahydrobiopterin did not change the ACh response. In isolated coronary arteries of WT mice, ACh-induced vasodilation occurred. Inhibition of glutathione reductase by 1, 3-bis(2-chloroethyl)-1-nitrosourea decreased ACh-induced vasodilation (n=10, p<0.01), which was restored by DTT. To evaluate the thiol oxidation, we measured the fluorescence of monochlorobimane (MCB) in coronary arteries, which covalently labels the total. The fluorescence level to MCB decreased in SMP30 KO mice, but with DTT treatment restored to a level comparable to that of WT mice. The reduced glutathione and total thiol levels were also low in the aorta of SMP30 KO mice compared with those of WT mice. Administration of ACh into the aortic sinus in vivo of SMP30 KO mice induced coronary artery spasm. INNOVATION The thiol redox state is a key regulator of endothelial NO synthase activity, and thiol oxidation was associated with endothelial dysfunction in the SMP30 deficiency model. CONCLUSION These results suggest that chronic thiol oxidation by oxidant stress is a trigger of coronary artery spasm, resulting in impaired endothelium-dependent vasodilation.

Senescence marker protein 30 has a cardio-protective role in doxorubicin-induced cardiac dysfunction.

Background Senescence marker protein 30 (SMP30), which was originally identified as an aging marker protein, is assumed to act as a novel anti-aging factor in the liver, lungs and brain. We hypothesized that SMP30 has cardio-protective function due to its anti-aging and anti-oxidant effects on doxorubicin (DOX)-induced cardiac dysfunction. Methods and Results SMP30 knockout (SMP30 KO) mice, SMP30 transgenic (SMP30 TG) mice with cardiac-specific overexpression of SMP30 gene and wild-type (WT) littermate mice at 12–14 weeks of age were given intra-peritoneal injection of DOX (20 mg/kg) or saline. Five days after DOX injection, echocardiography revealed that left ventricular ejection fraction was more severely reduced in the DOX-treated SMP30 KO mice than in the DOX-treated WT mice, but was preserved in the DOX-treated SMP30 TG mice. Generation of reactive oxygen species and oxidative DNA damage in the myocardium were greater in the DOX-treated SMP30 KO mice than in the DOX-treated WT mice, but much less in the SMP30 TG mice. The numbers of deoxynucleotidyltransferase-mediated dUTP nick end-labeling positive nuclei in the myocardium, apoptotic signaling pathways such as caspase-3 activity, Bax/Bcl-2 ratio and phosphorylation activity of c-Jun N-terminal kinase were increased in SMP30 KO mice and decreased in SMP30 TG mice compared with WT mice after DOX injection. Conclusions SMP30 has a cardio-protective role by anti-oxidative and anti-apoptotic effects in DOX-induced cardiotoxicity, and can be a new therapeutic target to prevent DOX-induced heart failure.

Senescence marker protein 30 inhibits angiotensin II-induced cardiac hypertrophy and diastolic dysfunction.

BACKGROUND AND OBJECTIVE Senescence marker protein 30 (SMP30) is assumed to behave as an anti-aging factor. Recently, we have demonstrated that deficiency of SMP30 exacerbates angiotensin II-induced cardiac hypertrophy, dysfunction and remodeling, suggesting that SMP30 may have a protective role in the heart. Thus, this study aimed to test the hypothesis that up-regulation of SMP30 inhibits cardiac adverse remodeling in response to angiotensin II. METHODS We generated transgenic mice with cardiac-specific overexpression of SMP30 gene using α-myosin heavy chain promoter. Transgenic mice and wild-type littermate mice were subjected to continuous angiotensin II infusion (800 ng/kg/min). RESULTS After 14 days, heart weight and left ventricular weight were lower in transgenic mice than in wild-type mice, although blood pressure was similarly elevated during angiotensin II infusion. Cardiac hypertrophy and diastolic dysfunction in response to angiotensin II were prevented in transgenic mice compared with wild-type mice. The degree of cardiac fibrosis by angiotensin II was lower in transgenic mice than in wild-type mice. Angiotensin II-induced generation of superoxide and subsequent cellular senescence were attenuated in transgenic mouse hearts compared with wild-type mice. CONCLUSIONS Cardiac-specific overexpression of SMP30 inhibited angiotensin II-induced cardiac adverse remodeling. SMP30 has a cardio-protective role with anti-oxidative and anti-aging effects and could be a novel therapeutic target to prevent cardiac hypertrophy and remodeling due to hypertension.

Plasma volume status predicts prognosis in patients with acute heart failure syndromes

Background: The intravascular compartment is known as the plasma volume, and the extravascular compartment represents fluid within the interstitial space. Plasma volume expansion is a major symptom of heart failure. The aim of the current study was to investigate the impact of plasma volume status on the prognosis of acute heart failure syndromes. Methods and results: We analyzed 1115 patients with acute heart failure syndromes who were admitted to our hospital. These patients were divided into three groups based on their plasma volume status at admission: first tertile (plasma volume status <41.9%, n = 371), second tertile (41.9%⩽ plasma volume status <49.0%, n = 372), and third tertile (49.0%⩽ plasma volume status, n = 372). Plasma volume status was defined as follows: actual plasma volume = (1 − hematocrit) × [a + (b × body weight)] (a=1530 in males and a=864 in females, b=41.0 in males and b=47.9 in females); ideal plasma volume = c × body weight (c=39 in males and c=40 in females); and plasma volume status = [(actual plasma volume − ideal plasma volume)/ideal plasma volume] × 100 (%). In the Kaplan–Meier analysis, all-cause mortality, cardiac mortality and cardiac events increased progressively from the first to third tertile (p <0.001, respectively). In the Cox proportional hazard analysis, after adjusting for potential confounding factors, plasma volume status was an independent predictor of all-cause mortality (hazard ratio 1.429, p < 0.001), cardiac mortality (hazard ratio 1.416, p = 0.001) and cardiac events (hazard ratio 1.207, p = 0.004). Conclusion: Increased congestion is associated with increased morbidity and mortality in heart failure patients. Plasma volume status, which represents intravascular compartment and congestion, can identify poor prognosis in patients with acute heart failure syndromes.

Liver stiffness assessed by Fibrosis-4 index predicts mortality in patients with heart failure

Objective Liver dysfunction due to heart failure (HF) is known as congestive hepatopathy. It has recently been reported that liver stiffness assessed by transient elastography reflects increased central venous pressure. The Fibrosis-4 (FIB4) index (age (years) × aspartate aminotransferase (IU/L)/platelet count (109/L) × square root of alanine aminotransferase (IU/L)) is expected to be useful for evaluating liver stiffness in patients with non-alcoholic fatty liver disease. We aimed to investigate the impact of the FIB4 index on HF prognosis, with consideration for liver fibrosis markers and underlying cardiac function. Methods Consecutive 1058 patients with HF who were admitted to our hospital were divided into three groups based on their FIB4 index: first (FIB4 index <1.72, n=353), second (1.72≤FIB4 index <3.01, n=353) and third tertiles (3.01≤FIB4 index, n=352). We prospectively followed for all-cause mortality. Results During the follow-up period (mean 1047 days), 246 deaths occurred. In the Kaplan-Meier analysis, all-cause mortality progressively increased from the first to third groups (12.2%, 21.0% and 36.6%, p<0.01). In the Cox proportional hazard analysis, FIB4 index was an independent predictor of all-cause mortality in patients with HF (p<0.05). In comparisons of laboratory and echocardiographic findings, the third tertile had higher levels of type IV collagen 7S, procollagen type III peptide, hyaluronic acid, left atrial volume, mitral valve E/e’, inferior vena cava diameter and right atrial end systolic area (p<0.01, respectively). Conclusion The FIB4 index, a marker of liver stiffness, is associated with higher all-cause mortality in patients with HF.