Mitochondrial DNA integrity and function are critical for endothelium-dependent vasodilation in rats with metabolic syndrome.

Endothelial dysfunction in diabetes is generally attributed to oxidative stress, but this view is challenged by observations showing antioxidants do not eliminate diabetic vasculopathy. As an alternative to oxidative stress-induced dysfunction, we interrogated if impaired mitochondrial function in endothelial cells is central to endothelial dysfunction in the metabolic syndrome. We observed reduced coronary arteriolar vasodilation to the endothelium-dependent dilator, acetylcholine (Ach), in Zucker Obese Fatty rats (ZOF, 34 ± 15% [mean ± standard deviation] 10-3 M) compared to Zucker Lean rats (ZLN, 98 ± 11%). This reduction in dilation occurred concomitantly with mitochondrial DNA (mtDNA) strand lesions and reduced mitochondrial complex activities in the endothelium of ZOF versus ZLN. To demonstrate endothelial dysfunction is linked to impaired mitochondrial function, administration of a cell-permeable, mitochondria-directed endonuclease (mt-tat-EndoIII), to repair oxidatively modified DNA in ZOF, restored mitochondrial function and vasodilation to Ach (94 ± 13%). Conversely, administration of a cell-permeable, mitochondria-directed exonuclease (mt-tat-ExoIII) produced mtDNA strand breaks in ZLN, reduced mitochondrial complex activities and vasodilation to Ach in ZLN (42 ± 16%). To demonstrate that mitochondrial function is central to endothelium-dependent vasodilation, we introduced (via electroporation) liver mitochondria (from ZLN) into the endothelium of a mesenteric vessel from ZOF and restored endothelium-dependent dilation to vasoactive intestinal peptide (VIP at 10-5 M, 4 ± 3% vasodilation before mitochondrial transfer and 48 ± 36% after transfer). Finally, to demonstrate mitochondrial function is key to endothelium-dependent dilation, we administered oligomycin (mitochondrial ATP synthase inhibitor) and observed a reduction in endothelium-dependent dilation. We conclude that mitochondrial function is critical for endothelium-dependent vasodilation.

Reduction of door-to-balloon time in patients with ST-elevation myocardial infarction by single-catheter primary percutaneous coronary intervention method.

OBJECTIVES: The objectives of this study is to confirm reduction of door-to-balloon (D2B) time with single-catheter percutaneous coronary intervention (SC-PCI) method. BACKGROUND: Reduction of total ischemic time is important in the emergency treatment of ST-elevation myocardial infarction (STEMI). There have been no established methods in primary percutaneous coronary intervention (PCI) to shorten ischemic time via radial access. Ikari left curve was reported as a universal guiding catheter for left and right coronary arteries. Several procedure steps can be skipped by SC-PCI method as the advantage of a universal catheter. METHODS: This study is a retrospective analysis of a total of 1,275 consecutive STEMI cases treated with primary PCI in 14 hospitals. Patients were divided into two groups, SC-PCI method (n = 298) and conventional PCI method (n = 977). Primary endpoints were door-to-balloon (D2B) time and radiation exposure dose. RESULTS: The mean age was 68 ± 13 years old. Radial access was used in 85% of participants. PCI success was achieved in 99.5% of participants and the SC-PCI method was successfully performed in 92.6%. The D2B time was shorter (68 ± 46 vs. 74 ± 50 min, respectively; p = .02), and the radiation exposure dose was lower (1,664 ± 970 vs. 2008 ± 1,605 mGy, respectively; p < .0001) in the SC-PCI group than in the conventional group. CONCLUSION: Primary PCI with SC-PCI method for patients with STEMI demonstrated shorter D2B time and lower radiation exposure dose.

Clinical characteristics and prognosis of patients with microvascular angina: an international and prospective cohort study by the Coronary Vasomotor Disorders International Study (COVADIS) Group.

AIMS: To provide multi-national, multi-ethnic data on the clinical characteristics and prognosis of patients with microvascular angina (MVA). METHODS AND RESULTS: The Coronary Vasomotor Disorders International Study Group proposed the diagnostic criteria for MVA. We prospectively evaluated the clinical characteristics of patients according to these criteria and their prognosis. The primary endpoint was the composite of major cardiovascular events (MACE), verified by institutional investigators, which included cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalization due to heart failure or unstable angina. During the period from 1 July 2015 to 31 December 2018, 686 patients with MVA were registered from 14 institutes in 7 countries from 4 continents. Among them, 64% were female and the main ethnic groups were Caucasians (61%) and Asians (29%). During follow-up of a median of 398 days (IQR 365-744), 78 MACE occurred (6.4% in men vs. 8.6% in women, P = 0.19). Multivariable Cox proportional hazard analysis disclosed that hypertension and previous history of coronary artery disease (CAD), including acute coronary syndrome and stable angina pectoris, were independent predictors of MACE. There was no sex or ethnic difference in prognosis, although women had lower Seattle Angina Questionnaire scores than men (P < 0.05). CONCLUSIONS: This first international study provides novel evidence that MVA is an important health problem regardless of sex or ethnicity that a diagnosis of MVA portends a substantial risk for MACE associated with hypertension and previous history of CAD, and that women have a lower quality of life than men despite the comparable prognosis.

Correction to: Switching from Warfarin to rivaroxaban induces sufficiency of vitamin K and reduction of arterial stiffness in patients with atrial fibrillation.

In the original publication of the article,one of the author's name was published incorrectly as "Takamoto Furuki".

Switching from Warfarin to rivaroxaban induces sufficiency of vitamin K and reduction of arterial stiffness in patients with atrial fibrillation.

Use of chronic vitamin K antagonist (VKA) induces a long-term deficiency of vitamin K, which may cause arterial stiffness and bone-related disease. Switching from VKA to rivaroxaban could induce rapid sufficiency of vitamin K and improvement of arterial stiffness. The K2 SUMMIT-3 study is a multicenter, open-label, prospective, and randomized design. Patients with atrial fibrillation who have been taking VKA for more than 6 months but less than 10 years were randomly assigned to two groups; those switching from VKA to rivaroxaban and those continuing with VKA medication. The primary endpoint was the percentage difference of brachial-ankle pulse wave velocity (baPWV) in 3 months. A total of 77 patients were randomly assigned to receive rivaroxaban (n = 38) or VKA (n = 39). The average age was 74 ± 9 years. The duration for which VKA was prescribed prior to randomization was 90 ± 87 months.Abnormally high levels of Des-gamma carboxyprothrombin (PIVKA-II) or uncarboxylated osteocalcin (ucOC) indicating vitamin K insufficiency were observed in 100% or 82% of the patients at baseline but it reduced to 2% (p < 0.0001) or 55% (p = 0.01) at 3 months in the rivaroxaban group. To the contrary, theses data had no changes in the VKA group. The percentage difference in baPWV was - 1.4 ± 10.0% vs. 3.5 ± 14.7% in the rivaroxaban and the VKA groups, respectively. (p = 0.02). Switching from VKA to rivaroxaban resulted in rapid sufficiency of vitamin K and reduction of arterial stiffness in 3 months.

Questionnaire in patients with aborted sudden cardiac death due to coronary spasm in Japan.

OBJECTIVES: We investigated the medical or mechanical therapy, and the present knowledge of Japanese cardiologists about aborted sudden cardiac death (ASCD) due to coronary spasm. METHODS: A questionnaire was developed regarding the number of cases of ASCD, implantable cardioverter-defibrillator (ICD), and medical therapy in ASCD patients due to coronary spasm. The questionnaire was sent to the Japanese general institutions at random in 204 cardiology hospitals. RESULTS: The completed surveys were returned from 34 hospitals, giving a response rate of 16.7%. All SCD during the 5 years was observed in 5726 patients. SCD possibly due to coronary spasm was found in 808 patients (14.0%) and ASCD due to coronary spasm was observed in 169 patients (20.9%). In 169 patients with ASCD due to coronary spasm, one or two coronary vasodilators was administered in two-thirds of patients [113 patients (66.9%)], while more than 3 coronary vasodilators were found in 56 patients (33.1%). ICD was implanted in 117 patients with ASCD due to coronary spasm among these periods including 35 cases with subcutaneous ICD. Majority of cause of ASCD was ventricular fibrillation, whereas pulseless electrical activity was observed in 18 patients and complete atrioventricular block was recognized in 7 patients. Mean coronary vasodilator number in ASCD patients with ICD was significantly lower than that in those without ICD (2.1 ± 0.9 vs. 2.6 ± 1.0, p < 0.001). Although 16 institutions thought that the spasm provocation tests under the medications had some clinical usefulness of suppressing the next fatal arrhythmias, spasm provocation tests under the medication were performed in just 4 institutions. CONCLUSIONS: In the real world, there was no fundamental strategy for patients with ASCD due to coronary spasm. Each institution has each strategy for these patients. Cardiologists should have the same strategy and the same knowledge about ASCD patients due to coronary spasm in the future.

Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage.

Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process.

Sirolimus eluting coronary stent implantation in patients on maintenance hemodialysis: the OUCH study (outcome of cypher stent inhemodialysis patients).

BACKGROUND: Pivotal studies on drug-eluting stents have excluded hemodialysis (HD) patients. No quantitative coronary angiography (QCA) analysis has been reported. METHODS AND RESULTS: The OUtcome of Cypher stent in Hemodialysis patients (OUCH) Study is a prospective non-randomized single-arm registry designed to assess the results of sirolimus-eluting stents in HD patients, with follow-up QCA in an independent core laboratory. The primary endpoint was the occurrence of target-vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target-vessel revascularization (TVR) at 1 year. A total of 117 patients were enrolled. The TVF rate was 24.9% (2.6% cardiac death, 1.4% MI, 23.9% TVR), and stent thrombosis was documented in 1 patient (0.9%). Coronary calcification was a predictor of TVF. Late lumen loss (LLL) averaged 0.69±0.93mm. The histogram of LLL showed that a total of 76% of lesions were distributed the same normally as that in normal renal function (average LLL 0.20±0.29mm), but 24% of lesions were outliers (average LLL 2.07±0.62mm). CONCLUSIONS: This report describes different clinical and QCA results in HD patients as higher TVF rate, different predictive factors, and different histogram of LLL compared with normal renal function. The different histogram of LLL was the existence of many outliers with the same average and the same deviation, suggesting the loss of sirolimus had an effect on a significant number of HD patients.

Acute vasoreactivity testing with nicardipine in patients with pulmonary arterial hypertension.

Acute vasoreactivity testing for patients with pulmonary arterial hypertension (PAH) has been reported to be useful to identify patients with sustained beneficial response to oral calcium-channel blockers (CCBs), but there is a risk of exacerbation during the testing with oral CCBs. Therefore, we developed a testing method utilizing intravenous nicardipine, a short-acting CCB, and examined the safety and usefulness of acute vasoreactivity testing with nicardipine in PAH patients. Acute vasoreactivity testing with nicardipine was performed in 65 PAH patients. Nicardipine was administered by short-time continuous infusion (1 µg·kg⁻¹·min⁻¹ for 5 min and 2 µg·kg⁻¹·min⁻¹ for 5 min) followed by bolus injection (5 µg/kg). Hemodynamic responses were continuously measured using a right heart catheter. Acute responders were defined as patients who showed a decrease in mean pulmonary artery pressure of at least 10 mmHg to an absolute level below 40 mmHg with preserved or increased cardiac output. Two acute responders and sixty-three non-acute responders were identified. There was no hemodynamic instability requiring additional inotropic agents or death during the testing. Acute responders had good responses to long-term oral CCBs. The acute vasoreactivity testing with nicardipine might be safe and useful for identifying CCB responders in PAH patients.

Effects of propofol on left ventricular mechanoenergetics in the excised cross-circulated canine heart.

Although propofol is commonly used for general anesthesia, its direct effects on left ventricular (LV) contractility and energetics remain unknown. Accordingly, we studied the effects of intracoronary propofol on excised cross-circulated canine hearts using the framework of the Emax (a contractility index)-PVA (systolic pressure-volume area, a measure of total mechanical energy)-V(O2) (myocardial oxygen consumption per beat) relationship. We obtained 1) the V(O2)-PVA relationship of isovolumic contractions with varied LV volumes at a constant Emax, 2) the V(O2)-PVA relationship with varied LV volumes at a constant intracoronary concentration of propofol, and 3) the V(O2)-PVA relationship under increased intracoronary concentrations of either propofol or CaCl(2) at a constant LV volume to assess the cardiac mechanoenergetic effects of propofol. We found that propofol decreased Emax dose-dependently. The slope of the linear V(O2)-PVA relationship (oxygen cost of PVA) remained unchanged by propofol. The PVA-independent V(O2)-Emax relationship (oxygen cost of Emax) was the same for propofol and Ca(2+). In conclusion, propofol showed a direct negative inotropic effect on LV. At its clinical concentrations, decreases in contractility by propofol were relatively small. Propofol shows mechanoenergetic effects on the LV that are similar to those of Ca(2+) blockers or ß-antagonists-i.e., it exerts negative inotropic effects without changing the oxygen costs of Emax and PVA.

International prospective cohort study of microvascular angina - Rationale and design.

BACKGROUND: Patients with signs and symptoms of myocardial ischemia and non-obstructive coronary artery disease (CAD) frequently have coronary functional abnormalities, including coronary microvascular dysfunction. Those with the latter are grouped under the term "microvascular angina" (MVA). Although diagnostic criteria exist for MVA, as recently proposed by our COVADIS (COronary VAsomotor Disorders International Study) group and the condition has been increasingly recognized in clinical practice, the clinical characteristics and long-term prognosis of MVA patients in the current era remain to be fully elucidated. AIMS: In the present study, we aimed to prospectively assess the clinical characteristics and long-term prognosis of MVA subjects in the current era in an international, multicenter, observational, and prospective registry study. METHODS: A total of 15 medical centers across 7 countries (USA, UK, Germany, Spain, Italy, Australia, and Japan) enrolled subjects fulfilling the COVADIS diagnostic criteria for MVA as follows; (1) signs and/or symptoms of myocardial ischemia, (2) absence of obstructive CAD, and (3) objective evidence of myocardial ischemia and/or coronary microvascular dysfunction. The primary endpoint was the composite of major cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, hospitalization due to heart failure or unstable angina. Between July 2015 and December 2018, a total of 706 subjects with MVA (M/F 256/450, 61.1 ± 11.8 [SD] yrs.) were registered. Subjects will be followed for at least 1 year. SUMMARY: The present study will provide important information regarding the clinical characteristics, management, and long-term prognosis of MVA patients in the current era.

Clinical characteristics and long-term prognosis of contemporary patients with vasospastic angina: Ethnic differences detected in an international comparative study.

BACKGROUND: Possible ethnic differences in clinical characteristics and long-term prognosis of contemporary patients with vasospastic angina (VSA) remain to be elucidated. METHODS AND RESULTS: The Japanese Coronary Spasm Association (JCSA) conducted an international, prospective, and multicenter registry study for VSA patients. A total of 1457 VSA patients (Japanese/Caucasians, 1339/118) were enrolled based on the same diagnostic criteria. Compared with Caucasian patients, Japanese patients were characterized by higher proportions of males (68 vs. 51%) and smoking history (60 vs. 49%). Japanese patients more often had angina especially during the night and early morning hours, compared with Caucasians. Ninety-five percent of Japanese and 84% of Caucasian patients underwent pharmacological provocation test. Importantly, no significant differences in the patterns of coronary spasm were apparent, with diffuse spasm most frequently noted in both ethnicities. The prescription rate of calcium-channel blockers was higher in Japanese (96 vs. 86%), whereas the uses of nitrates (46 vs. 59%), statins (43 vs. 65%), renin-angiotensin-system inhibitors (27 vs. 51%), and ß-blockers (10 vs. 24%) were more common in Caucasian patients. Survival rate free from major adverse cardiac events (MACE) was slightly but significantly higher in Japanese than in Caucasians (86.7 vs. 76.6% at 5 years, P < 0.001). Notably, multivariable analysis revealed that the JCSA risk score correlated with MACE rates not only in Japanese but also in Caucasian patients. CONCLUSION: These results indicate that there are ethnic differences in clinical profiles and long-term prognosis of contemporary VSA patients.

Hydrogen peroxide: a feed-forward dilator that couples myocardial metabolism to coronary blood flow.

OBJECTIVE: We tested the hypothesis that hydrogen peroxide (H2O2), the dismutated product of superoxide (O2*-), couples myocardial oxygen consumption to coronary blood flow. Accordingly, we measured O2*- and H2O2 production by isolated cardiac myocytes, determined the role of mitochondrial electron transport in the production of these species, and determined the vasoactive properties of the produced H2O2. METHODS AND RESULTS: The production of O2*- is coupled to oxidative metabolism because inhibition of complex I (rotenone) or III (antimycin) enhanced the production of O2*- during pacing by about 50% and 400%, respectively; whereas uncoupling oxidative phosphorylation by decreasing the protonmotive force with carbonylcyanide-p-trifluoromethoxyphenyl-hydrazone (FCCP) decreased pacing-induced O2*- production. The inhibitor of cytosolic NAD(P)H oxidase assembly, apocynin, did not affect O2*- production by pacing. Aliquots of buffer from paced myocytes produced vasodilation of isolated arterioles (peak response 67+/-8% percent of maximal dilation) that was significantly reduced by catalase (5+/-0.5%, P<0.05) or the antagonist of Kv channels, 4-aminopyridine (18+/-4%, P<0.05). In intact animals, tissue concentrations of H2O2 are proportionate to myocardial oxygen consumption and directly correlated to coronary blood flow. Intracoronary infusion of catalase reduced tissue levels of H2O2 by 30%, and reduced coronary flow by 26%. Intracoronary administration of 4-aminopyridine also shifted the relationship between myocardial oxygen consumption and coronary blood flow or coronary sinus pO2. CONCLUSIONS: Taken together, our results demonstrate that O2*- is produced in proportion to cardiac metabolism, which leads to the production of the vasoactive reactive oxygen species, H2O2. Our results further suggest that the production of H2O2 in proportion to metabolism couples coronary blood flow to myocardial oxygen consumption.

Beneficial effect of hydroxyfasudil, a specific Rho-kinase inhibitor, on ischemia/reperfusion injury in canine coronary microcirculation in vivo.

OBJECTIVES: We examined whether hydroxyfasudil, a specific Rho-kinase inhibitor, exerts cardioprotective effect on coronary ischemia/reperfusion (I/R) injury and, if so, whether nitric oxide (NO) is involved. BACKGROUND: Recent studies have demonstrated that Rho-kinase is substantially involved in the pathogenesis of cardiovascular diseases; however, it remains to be examined whether it is also involved in ischemia/reperfusion (I/R) injury. METHODS: Canine subepicardial small arteries (SA, >or=100 microm) and arterioles (A, <100 microm) were observed by a charge-coupled device intravital microscope during I/R. Coronary vascular responses to endothelium-dependent (acetylcholine, intracoronary [IC]) and -independent (papaverine, IC) vasodilators were examined after I/R under the following four conditions: control (n = 7), NO synthase inhibitor alone (N(G)-monomethl-L-arginine [L-NMMA], IC, n = 4), hydroxyfasudil alone (IC, n = 7), and hydroxyfasudil plus L-NMMA (n = 7). RESULTS: Hydroxyfasudil significantly attenuated serotonin (IC)-induced vasoconstriction of SA (-7 +/- 1% vs. 2 +/- 1%, p < 0.01). Coronary I/R significantly impaired coronary vasodilation to acetylcholine after I/R (SA, p < 0.05; and A, p < 0.01 vs. before I/R) and L-NMMA further reduced the vasodilation, whereas hydroxyfasudil completely preserved the responses. The vasoconstriction by L-NMMA after I/R was significantly improved by hydroxyfasudil in both-sized arteries (both p < 0.01). Expression of endothelial nitric oxide synthase (eNOS) protein in the ischemic endocardium of left anterior descending coronary artery area (as determined by Western blotting) significantly decreased (79 +/- 4%) compared with the nonischemic endocardium of LCX area (100 +/- 7%), which was improved by hydroxyfasudil (105 +/- 6%, p < 0.01). Hydroxyfasudil significantly reduced myocardial infarct size, and hydroxyfasudil with L-NMMA also reduced the infarct size compared with L-NMMA alone. CONCLUSIONS: Hydroxyfasudil exerts cardioprotective effects on coronary I/R injury in vivo, in which NO-mediated mechanism may be involved through preservation of eNOS expression.

Role of focal adhesion kinase in flow-induced dilation of coronary arterioles.

BACKGROUND: Flow-induced regulation of endothelial NO synthase (eNOS) depends on integrin signaling and tyrosine kinase activation. Integrins cluster in focal adhesion complexes, where the extracellular matrix is connected to the cytoskeleton and where focal adhesion kinase (FAK) is located. FAK plays a central role in integrin signaling and Src activation. Accordingly, we hypothesized that FAK plays an important role in flow-induced dilation (FID). METHODS AND RESULTS: To inactivate FAK-dependent signaling, anti-FAK, phosphospecific (Tyr397) antibody (FAKab), which binds against the FAK autophosphorylation site, was incorporated into endothelium of rat coronary arterioles using liposomal transfection. The responses to flow, acetylcholine (Ach), or the NO donor MAHAMANONOate (NOC-9) were observed before and after FAKab. In control and vehicles (denatured antibody or transfecting reagent alone), flow produced progressive dilation to a maximal value of 35% increase in diameter, which was inhibited by Nomega-nitro-L-arginine methyl ester (L-NAME). However, FAKab prevented FID (P<0.01 versus control). Combined treatment with FAKab and L-NAME did not produce inhibition greater than FAKab alone. FAKab did not blunt Ach- or NOC-9-induced dilation. Western analysis demonstrated that FAKab prevented flow-induced phosphorylation of FAK (pY397-FAK), Akt (pS473-Akt), and eNOS (pS1179-eNOS). CONCLUSIONS: Our study demonstrates the pivotal role of FAK in NO-mediated FID. Inhibition of FAK signaling with FAKab impaired FID and phosphorylation of Akt and eNOS. Our data suggest that the activation of FAK is central to the mechanotransduction of FID via regulation of activation of Akt and eNOS.

Celsior preserves cardiac mechano-energetics better than University of Wisconsin solution by preventing oxidative stress.

OBJECTIVES: Identity of the optimal heart preservation solution remains unknown. Because oxidative stress contributes to contractile failure in the ischaemic/reperfused myocardium and the main characteristic of Celsior is its antioxidant effect, it is important to elucidate the relationship between the inhibitory effect on oxidative stress and cardiac mechano-energetics. We therefore evaluated the efficacy of Celsior from both aspects by comparison with the University of Wisconsin solution (UWS). METHODS: We used 18 excised cross-circulated canine hearts. Excised hearts were preserved with UWS (n = 6) or Celsior (n = 6) for 3 h at 4 °C; the remaining six served as controls. Hearts were then cross-circulated and rewarmed. The end-systolic pressure-volume ratio (LV Emax) and the ventricular pressure-volume area, which is a measure of total mechanical energy, were assessed after reperfusion. Biopsies were taken from the endocardium after excising the heart, before reperfusion, after reperfusion and 4 h after reperfusion to assess the inhibitory effect of each agent on oxidative stress. Endo-myocardial biopsy samples were studied immunohistochemically for expression of 4-hydroxy-2-nonenal (HNE)-modified protein, which is a major lipid peroxidation product. RESULTS: Emax in the UWS group was significantly smaller than in the control group, whereas the Emax in the Celsior group was preserved. Oxygen cost of Emax in the UWS group was significantly higher than in the Celsior group. Myocardial HNE-modified protein levels increased gradually, both under preservation and after reperfusion in the UWS group. Myocardial HNE-modified protein levels in the Celsior group were lower, mainly before and 4 h after reperfusion compared with the UWS group. CONCLUSIONS: Celsior may maintain cardiac contractility and conserve oxygen cost by inhibiting oxidative stress.

Regression of capillary network in atrophied soleus muscle induced by hindlimb unweighting.

Little is known about the mechanisms responsible for the adaptation and changes in the capillary network of hindlimb unweighting (HU)-induced atrophied skeletal muscle, especially the coupling between functional and structural alterations of intercapillary anastomoses and tortuosity of capillaries. We hypothesized that muscle atrophy by HU leads to the apoptotic regression of the capillaries and intercapillary anastomoses with their functional alteration in hemodynamics. To clarify the three-dimensional architecture of the capillary network, contrast medium-injected rat soleus muscles were visualized clearly using a confocal laser scanning microscope, and sections were stained by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) and with anti-von Willebrand factor. In vivo, the red blood cell velocity of soleus muscle capillaries were determined with a pencil-lens intravital microscope brought into direct contact with the soleus surface. After HU, the total muscle mass, myofibril protein mass, and slow-type myosin heavy chain content were significantly lower. The number of capillaries paralleling muscle fiber and red blood cells velocity were higher in atrophied soleus. However, the mean capillary volume and capillary luminal diameter were significantly smaller after HU than in the age-matched control group. In addition, we found that the number of anastomoses and the tortuosity were significantly lower and TUNEL-positive endothelial cells were observed in atrophied soleus muscles, especially the anastomoses and/or tortuous capillaries. These results indicate that muscle atrophy by HU generates structural alterations in the capillary network, and apoptosis appears to occur in the endothelial cell of the muscle capillaries.

Exponential fitting of postextrasystolic potentiation may underestimate the cardiac Ca2+ recirculation fraction: a theoretical analysis.

The recirculation fraction of intramyocardial Ca(2+) (RF) has conventionally been obtained from the monotonic decay of postextrasystolic potentiation (PESP). The used assumption is that the decay is exponential. However, we have found that PESP usually decays in alternans even at spontaneous heart rates (>100 beats/min) in excised, cross-circulated canine heart preparations under normal coronary perfusion and normothermia. We have already devised a means of extracting the exponential decay component for RF calculation by subtracting the oscillatory component from the alternans PESP decay by a curve-fitting method. Using mathematics, we assessed the possible error in estimated RF when an exponential curve was naively fit to the alternans PESP decay. We obtained results showing that the exponential assumption may considerably underestimate RF even when the alternans is trivial with the oscillatory component of only 10% of the exponential component.

Mid-ventricular obstructive hypertrophic cardiomyopathy with an apical aneurysm caused by vasospastic angina.

Mid-ventricular obstructive hypertrophic cardiomyopathy (MVOHCM) is a rare form of cardiomyopathy, characterized by the presence of a pressure gradient between the left ventricular basal and apical chambers and is frequently associated with an apical aneurysm. However, the exact cause of this aneurysm remains unknown. We here describe a patient with MVOHCM in whom the apical aneurysm may be caused by vasospastic angina.

A case of vasospastic angina in which the ergonovine provocation test with intracoronary isosorbide dinitrate and nicorandil was effective in the diagnosis of microvascular spasm.

A 60-year-old man was admitted with early morning angina while at rest. Coronary angiogram revealed no organic lesions; therefore, a spasm provocation test with ergonovine was performed. Administration of intracoronary ergonovine induced total occlusion of the right coronary artery. The induced total occlusion improved but coronary flow velocity remained severely reduced and chest discomfort with ST-T changes in ECG remained in spite of repeated administration of isosorbide dinitrate (ISDN). Intracoronary administration of nicorandil following ISDN alleviated the chest discomfort, normalized the ST-T change in ECG, and improved the coronary flow. This suggested that microvascular spasm and the epicardial spasm were not relieved by ISDN but by nicorandil. Intracoronary nicorandil injection following ISDN administration may be useful for the diagnosis of microvascular spasm in the ergonovine provocation test.