Effect of postprandial hyperglycaemia on coronary flow reserve in patients with impaired glucose tolerance and type 2 diabetes mellitus.

BACKGROUND: This study investigated whether postprandial hyperglycaemia has an adverse effect on coronary microvascular function and left ventricular diastolic function. METHODS: In all, 28 patients with type 2 diabetes mellitus with no significant stenosis in left anterior descending artery were enrolled. In all subjects, plasma 1,5-anhydroglucitol was measured, and coronary flow reserve in the left anterior descending artery was evaluated using a Doppler wire. Membrane type-1 matrix metalloproteinase expression on circulating peripheral blood mononuclear cells was measured by flow cytometry. Correlation analyses were performed for coronary flow reserve and 1,5-anhydroglucitol, other coronary risk factors, membrane type-1 matrix metalloproteinase and E/e'. RESULTS: Strong correlations were found only between 1,5-anhydroglucitol and coronary flow reserve and membrane type-1 matrix metalloproteinase. On multiple regression analysis, 1,5-anhydroglucitol remained an independent predictor of coronary flow reserve (ß = 0.38, p = 0.048). CONCLUSION: Postprandial hyperglycaemia appears to have an adverse effect on coronary microvascular function, suggesting that improvement of postprandial hyperglycaemia may contribute to the improvement of coronary microvascular dysfunction.

Determinants of plasma renin activity: role of a human renin gene variant as a genetic factor.

The plasma renin activity (PRA) is affected by a number of environmental factors. However, significant heritability has been shown for the activity. A hypothesis that a candidate regulatory single-nucleotide polymorphism, C-5312T, of human renin gene should have a significant effect on PRA was elucidated and updating of independent determinants of PRA was attempted. Cross sectional study. Outpatient study. We enrolled consecutive 810 subjects who had consulted our hospitals for lifestyle-related diseases. Genotypes were assayed with genomic DNA for C-5312T. Among the genetic variants, the difference of PRA was evaluated. Monovariate linear regression analysis was performed to test the correlation between PRA and clinical variables. Finally, stepwise multiple regression analysis was performed to evaluate the independent determinants. On comparing 2 genotype groups, CC/CT and T allele homozygote, the geometric means of PRA were 0.778 and 0.941 ng/ml/h, respectively (F = 5.992, P = 0.015). Monovariate linear regression analysis revealed that a number of variables have a significant correlation with the activity, including urinary salt excretion. A stepwise multivariate regression analysis revealed that renin C-5312T variant (TT) is one of the independent determinants of PRA. Thus, for the first time, a human renin gene variant was associated with a significant increase in PRA as a genetic factor and the independent determinants for the activity were updated including genetic factor.

Genetic variant of the renin-angiotensin system and prevalence of type 2 diabetes mellitus: a modest but significant effect of aldosterone synthase.

Recent genome-wide association studies have identified multiple variants that confer risk of type 2 diabetes mellitus (DM). However, established associations explain only a part of the heritability. Thus, even at the genome-wide association studies era, candidate gene approach should be still useful. Recent interventional studies against the renin-angiotensin system (RAS) showed reduction in new onset of DM, implying the system is involved in the onset. We substantiated the hypothesis that genetic variants of RAS have significant association with prevalence of DM. We enrolled to the study consecutive 782 subjects who had consulted our hospitals for mainly lifestyle related diseases. They consisted of 282 (36.1 %) diabetes cases. Genotypes were assayed with genomic DNA for conventional four genes of the RAS, i.e., angiotensin converting enzyme (ACE) insertion/deletion variant, angiotensinogen (AGT) M235T variant, angiotensin II type I receptor (AT1) A1166C variant, and aldosterone synthase (CYP11B2) C-344T variant. Association between the genetic variants of the RAS and prevalence of type 2 DM was tested. A significant association of DM and CYP11B2 genotype was obtained. There was no significant association between DM and ACE, AGT and AT1 variants. A multivariate logistic regression showed that age, gender, and CYP11B2 genotype were independent factors for association to diabetes, the DM risk of CC/CT to TT being 1.40 (95 % CI 1.04-1.90, p = 0.029). Thus, it is concluded that a genetic variant of the RAS should have a modest but significant impact on the onset of type 2 diabetes mellitus.

Effects of combination therapy with olmesartan and azelnidipine on serum osteoprotegerin in patients with hypertension.

BACKGROUND: Vascular calcification is a potent predictor of plaque instability and cardiac events. Osteoprotegerin (OPG), well-known vascular calcification mediator, is a signaling molecule involved in bone remodeling, which has been implicated in the regulation of vascular calcification and atherogenesis. The purpose of this study was to compare the combination treatments of olmesartan/azelnidipine and olmesartan/diuretics on serum bone-related markers in patients with essential hypertension. METHODS AND RESULTS: A total of 48 patients with hypertension treated with 20 mg olmesartan were randomized to receive combination treatment with 16 mg azelnidipine (O/A group) or diuretics (1 mg indapamide; O/D group) for 12 months. Osteoprotegerin, matrix metalloproteinase 2 (MMP-2), and high-sensitive CRP (hs-CRP) were measured after 3 and 12 months of treatment. Cardio-ankle vascular index (CAVI) was measured as the arterial stiffness using a VaSera CAVI instrument at the same time points. In both groups, the systolic and diastolic blood pressure reduction is similar. Serum OPG, MMP-2, and hs-CRP were significantly decreased at 12 months in the O/A group (P < .05), while there were no significant reductions in the O/D group. CAVI was significantly improved at 12 months in both the treatment groups. The improvement in CAVI was significantly greater in the O/A group than in the O/D group. CONCLUSION: Azelnidipine, but not indapamide, combined with olmesartan, improved arterial stiffness and were associated with significant decrease in OPG, MMP-2, and hs-CRP concentrations. These results suggest that the beneficial effects of the combination treatments of olmesartan/azelnidipine on arterial stiffness are mediated by alteration in bone-remodeling and inflammatory markers.

Reverse blood flow-glucose metabolism mismatch indicates preserved oxygen metabolism in patients with revascularised myocardial infarction.

PURPOSE: Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) has been reported to be unreliable for identifying viable myocardium in acute myocardial infarction (AMI), especially in areas with discordance in myocardial blood flow (MBF) and glucose metabolism. In myocardium with decreased FDG uptake but preserved MBF, referred to as exhibiting reverse mismatch, myocardial viability remains controversial and little is known about the metabolic state. The aims of this study were to clarify substrate use and to estimate myocardial viability in infarct areas exhibiting reverse mismatch. METHODS: Eighteen AMI patients with successful revascularisation were included in this study. Two weeks after onset, (11)C-acetate and (18)F-FDG PET were performed to evaluate regional oxygen consumption (k mono), MBF and glucose metabolism. Free fatty acid (FFA) metabolism was evaluated with (123)I-15-(p-iodophenyl)-3-(R, S)-methylpentadecanoic acid (BMIPP) single photon emission computed tomography (SPECT). To assess wall motion, movement in left ventricular endocardial surface was calculated using ECG-gated (99m)Tc-tetrofosmin SPECT. RESULTS: The %k mono values in reverse mismatch segments (52.6 ± 13.6%) were not significantly different from those in non-infarct segments (60.4 ± 12.8%, p = 0.071) and normal match segments (preserved MBF and FDG uptake) (58.6 ± 11.6%, p = 0.396), although regional wall motion was more severely impaired (3.06 ± 2.52 mm vs 6.78 ± 3.17 mm, p < 0.0001, and vs 5.30 ± 2.33 mm, p = 0.042, respectively). Compared to segments with reduced match (reduced MBF and FDG uptake), %k mono and %BMIPP uptake were significantly higher in reverse mismatch segments (52.6 ± 13.6% vs 37.4 ± 8.9%, p = 0.0002, and 58.8 ± 10.6% vs 40.2 ± 10.7%, p < 0.0001). CONCLUSION: Reverse mismatch in reperfused AMI patients, high oxygen consumption and FFA metabolism were observed despite decreased glucose metabolism. We conclude that reverse mismatch indicated the myocardium with early restoration of MBF and aerobic FFA metabolism.

A crossover comparison of urinary albumin excretion as a new surrogate marker for cardiovascular disease among 4 types of calcium channel blockers.

BACKGROUND: At the intervention for cardiovascular disease (CVD), albuminuria is a new pivotal target. Calcium channel blocker (CCB) is one of the most expected agents. Currently CCBs have been classified by delivery system, half-life and channel types. We tested anti-albuminuric effect among 4 types of CCBs. METHODS: Subjects were 50 hypertensives (SBP/DBP 164.7±17.1/92.3±12.2mmHg, s-Cr 0.81±0.37mg/dl, urinary albumin excretion (UAE) 69.4 (33.5-142.6) mg/gCr). Four CCBs were administered in a crossover setting: nifedipine CR, a long biological half-life L type by controlled release; cilnidipine, an N/L type; efonidipine, a T/L type; and amlodipine, a long biological half-life L type. RESULTS: Comparable BP reductions were obtained. UAE at endpoints ware as follows (mg/gCr, *P<0.01): nifedipine CR 30.8 (17.3-81.1),* cilnidipine 33.9 (18.0-67.7),* efonidipine 51.0 (21.2-129.8), amlodipine 40.6 (18.7-94.7). By all agents, significant augmentations were observed in PRA, angiotensin I and angiotensin II (AngII). AngII at cilnidipine was significantly lower than that at amlodipine. PAC at cilnidipine and efonidipine was significantly lower than that at amlodipine. Nifedipine CR significantly reduced ANP concentration. CONCLUSIONS: It is revealed that only nifedipine CR and cilnidipine could reduce albuminuria statistically. Thus, it is suggested that the 2 CCBs might be favorable for organ protection in hypertensives.

Evaluation of systemic redox states in patients carrying the MELAS A3243G mutation in mitochondrial DNA.

BACKGROUND/AIMS: To clarify the change of systemic redox states in patients carrying the A3243G mutation in mitochondrial DNA (A3243G), we evaluated oxidative stress and antioxidant activity in the serum of patients. METHODS: Oxidative stress and antioxidant activity in the serum samples obtained from 14 patients carrying A3243G and from 34 healthy controls were analyzed using the diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) tests, respectively. RESULTS: The mean d-ROMs level of all patients was significantly greater than that of the controls (p < 0.005), and the mean BAP/d-ROMs ratio of all patients was significantly lower than that of the controls (p < 0.02). In the patients with a history of stroke-like episodes (n = 10), both mean d-ROMs and BAP levels were increased compared with those of the controls (both p < 0.01). The mean BAP level of the patients without a history of stroke-like episodes (n = 4) was significantly decreased compared with that of the controls (p < 0.001), but the mean d-ROMs levels were not significantly different. CONCLUSION: d-ROMs and BAP tests indicated that patients carrying A3243G are always exposed to underlying oxidative stress, even at a remission state of stroke-like episodes.

Serum deoxyribonuclease I activity can be a useful diagnostic marker for the early diagnosis of unstable angina pectoris or non-ST-segment elevation myocardial infarction.

BACKGROUND AND PURPOSE: Recently, serum deoxyribonuclease I (DNase I) activity has been highlighted as a potential diagnostic marker for transient myocardial ischemia. To evaluate whether serum DNase I activity can be a useful biomarker for diagnosing unstable angina pectoris (UAP) or non-ST-segment elevation myocardial infarction (NSTEMI), we investigated serial changes in DNase I levels after chest pain in UAP and NSTEMI (UAP/NSTEMI) patients. METHODS AND RESULTS: Thirty-three and ten patients classified into the UAP/NSTEMI and the chest pain syndrome (CPS) group, respectively, were enrolled. The serum DNase I activity levels within 3h after chest pain and the absolute median value of percentage differences in serum DNase I activity levels from admission to 3h after hospitalization in the UAP/NSTEMI patients was significantly higher than those in the CPS patients. We evaluated the patients to show positive results for DNase I activity if the serum levels or percentage differences exceeded the corresponding cut-off values. The sensitivity and specificity of DNase I within 6h after chest pain in the UAP/NSTEMI patients without elevated levels of cardiac troponin T and the MB isoenzyme of creatine kinase were 89% and 88%, respectively. CONCLUSIONS: Serum DNase I activity can be a useful marker for the early diagnosis of UAP/NSTEMI after the onset of chest pain, irrespective of the evidence of myocardial injury.

Aldosterone inhibits endothelial morphogenesis and angiogenesis through the downregulation of vascular endothelial growth factor receptor-2 expression subsequent to peroxisome proliferator-activated receptor gamma.

Angiogenesis plays a pivotal role in cardiovascular diseases such as ischemic heart disease, limb ischemia and heart failure, and has recently been shown to mediate various biological activities related to the pathogenesis of these diseases. In the present study, we evaluated the role of aldosterone in angiogenesis. Tube formation assay on Matrigel using human umbilical vein endothelial cells (HUVEC) revealed that aldosterone inhibited endothelial morphogenesis in a manner sensitive to eplerenone, a selective mineralocorticoid receptor antagonist. The anti-angiogenic effect of aldosterone was further confirmed by an in vivo angiogenesis assay using a Matrigel plug model in mice. Reverse transcription-mediated polymerase chain reaction and immunoblotting demonstrated that aldosterone downregulated the expression levels of vascular endothelial growth factor receptor-2 (VEGFR-2) and peroxisome proliferators-activated receptor gamma (PPAR gamma). VEGFR-2 expression was found to be enhanced in response to PPAR gamma activation by troglitazone, and attenuated by GW9662, a specific antagonist of PPAR gamma. In the tube formation assay, endothelial morphogenesis was stimulated by troglitazone, and inhibited by GW9662, indicating that PPAR gamma activation mediates positive regulation of angiogenesis through enhancement of VEGFR-2 expression. These data suggest that aldosterone inhibits angiogenesis through VEGFR-2 downregulation, subsequent to, at least in part, attenuation of PPAR gamma expression. The present findings provide a new insight into the possible therapeutic application of mineralocorticoid receptor blockade to various cardiovascular diseases.

In vivo functional brain imaging and a therapeutic trial of L-arginine in MELAS patients.

BACKGROUND: Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is the most common type of mitochondrial disease and is characterized by stroke-like episodes (SEs), myopathy, lactic acidosis, diabetes mellitus, hearing-loss and cardiomyopathy. The causal hypotheses for SEs in MELAS presented to date are angiopathy, cytopathy and neuronal hyperexcitability. L-arginine (Arg) has been applied for the therapy in MELAS patients. SCOPE OF REVIEW: We will introduce novel in vivo functional brain imaging techniques such as MRI and PET, and discuss the pathogenesis of SEs in MELAS patients. We will further describe here our clinical experience with L-arg therapy and discuss the dual pharmaceutical effects of this drug on MELAS. MAJOR CONCLUSIONS: Administration of L-arg to MELAS patients has been successful in reducing neurological symptoms due to acute strokes and preventing recurrences of SEs in the chronic phase. L-Arg has dual pharmaceutical effects on both angiopathy and cytopathy in MELAS. GENERAL SIGNIFICANCE: In vivo functional brain imaging promotes a better understanding of the pathogenesis and potential therapies for MELAS patients. This article is part of a Special Issue entitled Biochemistry of Mitochondria, Life and Intervention 2010.

First survey of the three gene polymorphisms (PON1 Q192R, eNOS E298D and eNOS C-786T) potentially associated with coronary artery spasm in African populations and comparison with worldwide data.

Three polymorphisms, Paraoxonase 1 (PON1) Q192R (C/G), endothelial nitric oxide synthase (eNOS) E298D (G/T) and eNOS T-786C have been suggested to be potentially associated with coronary artery spasm in Japanese patients. Data on worldwide populations are needed to clarify whether these associations could hold true for other populations. However, few data are available especially in Africans, spasm of which has been suggested to be an aetiology of myocardial infarction. Therefore, these polymorphisms were investigated in three Africans, Ovambos (n = 123), Ghanians (n = 118) and Xhosas (n = 96), together with Japanese (n = 96), by using polymerase chain reaction-restriction fragment length polymorphism analysis. Genotype-distributions of all these SNPs in African populations were significantly different from those in Caucasians, whereas were similar to those in Japanese population. African populations exhibit relatively higher frequency of spasm-associated G192 allele in PON1 Q192R being similar to Japanese population, however frequencies of spasm-associated T298 allele and -C786 allele in SNP eNOS E298D and T-786C, respectively, were conversely lower in Africans than Caucasians. Although healthy subjects have been recruited in this study, these findings may provide genetic background for elucidation of aetiology of spasm.

Abnormal myocardial energy-production state in mitochondrial cardiomyopathy and acute response to L-arginine infusion. C-11 acetate kinetics revealed by positron emission tomography.

BACKGROUND: Cardiomyopathy is a life-threatening condition in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (known as MELAS). However, no effective therapy has been available until now. In the present study cardiac energetics and acute effects of L-arginine (Arg) were evaluated in MELAS patients. METHODS AND RESULTS: The 6 patients with MELAS (M-group) and 6 volunteers (C-group) underwent dynamic C-11 acetate positron emission tomography (PET) imaging. TCA-cycle metabolic rate (k(mono)), myocardial efficiency (double product (DP)/k(mono)), and myocardial blood flow (MBF) were determined before and after L-Arg administration. Baseline k(mono) showed a lower value in the M-group than in the C-group (0.051±0.013 vs 0.070±0.019min(-1), P=0.055). On the other hand, baseline DP/k(mono) was significantly greater in the M-group (1.69±5.9 vs 0.95±1.2×10(5), P=0.004). After L-Arg administration, 4 patients showed significant elevation of k(mono). No relationship was observed between the distribution of k(mono) elevation and the increase in MBF. CONCLUSIONS: The TCA cycle metabolic rate is markedly suppressed in MELAS patients, indicating a shift in energy production to the anaerobic pathway, leading to a paradoxical increase in myocardial efficiency. L-Arg can enhance TCA-cycle metabolism, regardless of its vasodilatation effect, and can be used as a treatment for patients with mitochondrial cardiomyopathy.

A new-generation N/L-type calcium channel blocker leads to less activation of the renin-angiotensin system compared with conventional L type calcium channel blocker.

OBJECTIVE: Calcium channel blocker (CCB) is one of the most useful antihypertensive agents. However, the activation of the renin-angiotensin system (RAS) is an unfavorable characteristic. N-type calcium channel is thought to be involved in catecholamine's release. Accordingly, N/L-type CCB has a probability of less activation of the RAS. We substantiated the hypothesis that N/L-type CCB, cilnidipine, leads to less activation of the RAS compared with conventional L-type CCB, amlodipine. DESIGN: Randomized, cross-over study. SETTING: Outpatient study. PARTICIPANTS: Participants were 110 hypertensive patients [male/female 46/64, age 66.3 ± 10.8 years, systolic blood pressure (SBP)/diastolic blood pressure (DBP) 161.8 ± 16.9/92.9 ± 12.4 mmHg, s-Cr 0.77 ± 0.32 mg/dl, plasma renin activity (PRA) 0.65 ± 0.63 ng/ml per h, angiotensin I (AngI) 70.5 ± 77.3 pg/ml, angiotensin II (AngII) 5.2 ± 3.9 pg/ml, plasma aldosterone concentration (PAC) 76.3 ± 35.9 pg/ml, urinary albumin excretion (UAE) 108.1 ± 284.2 mg/gCr]. Amlodipine besilate or cilnidipine was administered for 12 weeks in a cross-over manner as a monotherapy with an intention-to-treat fashion by titrating doses. Final doses of amlodipine besilate and cilnidipine were 6.6 ± 2.7 and 13.7 ± 5.1 mg/day, respectively. MAIN OUTCOME MEASURES: Changes in blood pressure, PRA, AngI, AngII, PAC, UAE of baseline and each end of amlodipine besilate and cilnidipine administration. RESULTS: Results were as follows (amlodipine vs. cilnidipine): SBP/DBP (mmHg): 135.2 ± 11.7/79.8 ± 9.6 vs. 136.7 ± 13.2/79.5 ± 10.9, P = 0.22/0.74; PRA (ng/ml per h): 1.16 ± 1.03 vs. 0.95 ± 0.78, P < 0.01; AngI (pg/ml): 155.0 ± 306.4 vs. 101.8 ± 92.0, P < 0.05; AngII (pg/ml): 12.0 ± 12.3 vs. 7.1 ± 4.5, P < 0.001; PAC (pg/ml): 81.6 ± 37.9 vs. 74.3 ± 36.2, P < 0.05; UAE (mg/gCr): 145.4 ± 424.5 vs. 58.8 ± 125.1, P < 0.05. Thus, in spite of the comparable blood pressure reductions, each level of components of the RAS at cilnidipine administration was significantly lower than those at amlodipine. Apart from this, UAE at cilnidipine administration was also significantly lower than that at amlodipine. CONCLUSION: It is suggested that cilnidipine leads to less activation of the RAS compared with amlodipine for the first time in human clinical patients and therefore cilnidipine might be expected to be superior in organ protection in addition to the antialbuminuric effect.

PET imaging of redox and energy states in stroke-like episodes of MELAS.

In stroke-like episodes of patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), changes in oxidative stress and glucose metabolism and their sequence remain obscure. We developed a novel double imaging method using positron emission tomography (PET) with [(62)Cu]-diacetyl-bis(N4-methylthiosemicarbazone) ((62)Cu-ATSM) and [(18)F]-fluorodeoxyglucose ((18)FDG) to visualize the regional oxidative stress, glucose metabolism and blood flow in brain lesions of stroke-like episodes non-invasively and rapidly. These PET imagings were performed on a MELAS patient with stroke-like lesions, and clearly demonstrated that oxidative stress following hyperemia along with increased glucose metabolism plays crucial roles in the pathogenesis of MELAS stroke-like episodes.

Levels of serum deoxyribonuclease I activity on admission in patients with acute myocardial infarction can be useful in predicting left ventricular enlargement due to remodeling.

OBJECTIVES: Serum deoxyribonuclease I (DNase I) activity has recently been highlighted as a potential diagnostic marker for the early detection of an acute myocardial infarction (AMI). We evaluated whether the serum DNase I activity was associated with the parameters of the left ventricular (LV) remodeling after an AMI. METHODS: We measured the serum DNase I activity in 45 patients with an AMI who were admitted to our hospital within approximately 4 h of the onset of their chest pain. We also evaluated the LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV) of each patient by echocardiography at the time of admission and at 6 months after the onset of the AMI. RESULTS: The serum DNase I activity peaked at 3.5+/-2.0 h after the onset of the symptoms in the patients with an AMI, thereafter exhibiting a time-dependent decline within 12 h, and a return to the basal level within 24 h in almost all cases. Neither the LVEF, LVEDV, nor LVESV in each patient on admission exhibited a significant correlation to the peak levels of the serum DNase I activity. Although there was no correlation between the peak DNase I activity and LVEF at 6 months after the onset, a significant positive correlation of the peak DNase I activity with LVEDV and LVESV (r=0.48, p<0.001 and r=0.34, p=0.02, respectively) was found. Furthermore, the LVEDV at 6 months after the onset in the high DNase I activity group (> 17.9 U/L) were significantly higher than those in the low DNase I activity group (< or = 17.9 U/L) (118.0+/-28.2 ml vs 89.3+/-25.4 ml, p=0.026). CONCLUSIONS: The serum DNase I activity level may predict LV enlargement associated with remodeling after an AMI.

Synergy of aldosterone and high salt induces vascular smooth muscle hypertrophy through up-regulation of NOX1.

Aldosterone and excessive salt intake are obviously implicated in human arteriosclerosis. Aldosterone activates NADPH oxidase that induces superoxide production and cardiovascular cell hypertrophy. The activity of NADPH oxidase is influenced by the expression of its subunit, through which, vasoactive agents activate in the enzyme. Here, we show that aldosterone elicited overexpression of the NOX1 catalytic subunit of NADPH oxidase in the presence of high salt in A7r5 vascular smooth muscle cells. We also showed that NOX1 is a key subunit involved in physiological aldosterone-induced NADPH oxidase activation. Aldosterone dose-dependently increased NOX1 expression and NADPH activity, which subsequently caused superoxide over-production and A7r5 cell hypertrophy. However, aldosterone had little effect on any of NOX1, superoxide over-production and cell hypertrophy in NOX1 knock-down A7r5 cells. These results suggest that the aldosterone-induced effects are mainly generated through NOX1. Aldosterone-induced NOX1 over-expression was augmented by 145 mM sodium chloride, as compared with control medium containing 135 mM NaCl. However, NOX1 over-expression was not induced in the absence of aldosterone, even in the presence of 185 mM NaCl. The mineralocorticoid receptor antagonist, eplerenone, completely abolished NOX1 over-expression, indicating that aldosterone is essential for this process.

Serum deoxyribonuclease I activity can be used as a novel marker of transient myocardial ischaemia: results in vasospastic angina pectoris induced by provocation test.

AIMS: Serum deoxyribonuclease I (DNase I) activity has recently been highlighted as a potential diagnostic marker for detection of acute myocardial infarction. To evaluate whether serum DNase I activity is useful for detection of myocardial ischaemia, we investigated alteration of its levels after onset of vasospastic angina pectoris (VSAP), resulting in transient myocardial ischaemia, induced by the intracoronary ergonovine provocation test. METHODS AND RESULTS: Twenty-nine consecutive patients with suspected VSAP were subjected to the test. Patients were categorized as VSAP-positive (n = 13) or -negative (n = 16) based on development of angina. Serum samples were examined for DNase I activity before, immediately after, and 3, 6, and 24 h after the provocation tests. The serum DNase I activity increased significantly from the baseline 3 h after the provocation test in 11 patients of the VSAP-positive group whose levels of troponin T were within the normal range. Median of the percentage differences from the baseline in serum DNase I activity 3 h after the test was 32.1% (25th and 75th percentile: 28.6 and 42.0%, respectively; P = 0.000012). In the VSAP-negative group, levels of DNase I activity remained unchanged at any point of time after the provocation test. CONCLUSION: Transient myocardial ischaemia resulting from VSAP induces a significant elevation of serum DNase I activity. Therefore, serum DNase I activity may be applicable as a useful marker for detecting transient myocardial ischaemia.

Evaluation of respiratory chain failure in mitochondrial cardiomyopathy by assessments of 99mTc-MIBI washout and 123I-BMIPP/99mTc-MIBI mismatch.

Cardiomyopathy is one of the main features that determines prognosis in patients with mitochondrial encephalomyopathy. We investigated respiratory chain failure using 99mTc-MIBI- and 123I-BMIPP-SPECT in vivo in five patients with mitochondrial cardiomyopathty. With the lowering of cardiac function, the 99mTc-MIBI-washout rate (WOR) increased, and the 99mTc-MIBI-uptake decreased, conversely. In patients who showed severe cardiac involvement, 99mTc-MIBI-uptake was markedly reduced, and by contrast, 123I-BMIPP-uptake increased (123I-BMIPP/99mTc-MIBI mismatch). There were significant correlations between the WOR on 99mTc-MIBI-SPECT and interventricular septal thickness (IVST) on echocardiography and between WOR and left ventricular ejection fraction (LVEF) on 99mTc-MIBI-SPECT. The increased WOR and decreased uptake of 99mTc-MIBI were reflected by the lowered mitochondrial membrane potential created by mitochondrial respiratory chain whereas 123I-BMIPP/99mTc-MIBI mismatch may be created by the enhanced triglyceride-pool. These nuclear medicine techniques are the potential tools to evaluate the energy state in mitochondrial cardiomyopathy.