Significance of myocytes with positive DNA in situ nick end-labeling (TUNEL) in hearts with dilated cardiomyopathy: not apoptosis but DNA repair

BACKGROUND

The presence of apoptotic myocytes has been reported in human hearts with dilated cardiomyopathy (DCM) on the basis of a positive finding of DNA in situ nick end-labeling (TUNEL). However, ultrastructural evidence of myocyte apoptosis has not been obtained.

METHODS AND RESULTS

A total of 80 endomyocardial biopsies were obtained from right and left ventricles of 20 patients with DCM and 20 normal control subjects. TUNEL-positive myocytes were found by light microscope in 15% of DCM specimens (controls, 0%, P<0.05), and the percentage of TUNEL-positive myocytes per section in DCM was 1. 0+/-2.7% (mean+/-SD). According to TUNEL at the electron microscopic level (EM-TUNEL), immunogold particles, which label DNA breaks with 3'-OH terminals, were markedly accumulated in the bizarre-shaped nuclei, with widespread clumping of chromatin (so-called "hypertrophied nuclei") of the myocytes obtained from DCM. Their ultrastructure was neither apoptotic nor necrotic but rather that of living cells. Taq polymerase-based DNA in situ ligation assay, which detects double-stranded DNA fragments more specifically than TUNEL, did not detect a positive reaction in any case. In mirror sections, all of the TUNEL-positive myocytes in DCM simultaneously expressed proliferating cell nuclear antigen, which is required for both DNA replication and repair, but Ki-67, a replication-associated antigen, was completely negative in all cases, which appeared to rule out cell proliferation activity.

CONCLUSIONS

Most of the TUNEL-positive myocytes in hearts with DCM are not apoptotic but rather living cells with increasing activity of DNA repair.

"Apoptotic" myocytes in infarct area in rabbit hearts may be oncotic myocytes with DNA fragmentation: analysis by immunogold electron microscopy combined with In situ nick end-labeling

BACKGROUND

Modes of cell death have been defined morphologically as apoptosis and oncosis. Infarcted myocytes have been reported to show apoptosis, as revealed by DNA fragmentation by DNA ladder and by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) at the light microscopic level. We investigated whether TUNEL-positive infarcted myocytes have apoptotic or oncotic ultrastructures by using electron microscopic TUNEL, which can simultaneously observe the ultrastructure and DNA fragmentation of the same myocytes.

METHODS AND RESULTS

Thirty rabbits were divided into 5 groups (n=6 each) that were subjected to a sham operation or to 30-minute ischemia followed by 0-minute, 30-minute, 2-hour, or 4-hour reperfusion of a coronary artery. In the 2- and 4-hour reperfusion groups only, DNA electrophoresis showed a ladder pattern, and the light microscopic TUNEL finding was positive in the nuclei of myocytes localized in the infarcted area (6+/-2% and 11+/-3%, respectively). Electron microscopic TUNEL showed that nuclei with a significant accumulation of immunogold particles (indicating an electronic microscopic TUNEL-positive result) were observed only in the infarcted myocytes with irreversibly oncotic ultrastructures that were found in the hearts of the 2- and 4-hour reperfusion groups (41+/-3% and 83+/-4%, respectively). Irreversibly oncotic myocytes (indicated by swelling, inhomogeneously clumped chromatin in nuclei, dense bodies in mitochondria, and/or ruptured plasma membranes) were also seen in the 0- and 30-minute reperfusion groups, which did not exhibit TUNEL-positive myocytes. There was no evidence of apoptotic ultrastructures in the myocytes.

CONCLUSIONS

DNA fragmentation occurs in the myocytes that had already shown irreversibly oncotic, but not apoptotic, ultrastructures with ischemia and/or reperfusion. Therefore, DNA fragmentation itself does not always mean apoptosis, and so-called apoptotic infarcted myocytes may belong to a category of cell death other than apoptosis.

Role of apoptosis in the disappearance of infiltrated and proliferated interstitial cells after myocardial infarction

Myocardial infarction (MI) progresses from the acute death of myocytes and the infiltration of inflammatory cells into granulation, followed by scars. During the healing process, the myocardial interstitial cell population in the infarcted tissues increases markedly and then decreases. We postulated that apoptosis is responsible for this process. Twenty-four male Japanese white rabbits underwent a 30-minute occlusion of the left coronary artery followed by reperfusion for 2 days, 2 weeks, or 4 weeks (n=8 each). The histological features consisted of dead cardiomyocytes and marked leukocyte infiltration at 2 days after MI and granulation consisting of numerous alpha-smooth muscle actin-positive myofibroblasts, macrophage antigen-positive macrophages, and neovascularization at 2 weeks. At 4 weeks, the cellularity decreased markedly, and scars were evident. Interstitial cells with positive nick end labeling were significantly more frequent at the light microscopic level in the 2-day MI samples (5.3+/-3.6% in the center and 6.9+/-3.3% in the periphery of the infarct region) than in the 2-week (2.5+/-1.0%) and 4-week (0.5+/-0.5%) samples. DNA electrophoresis showed a clear ladder in tissues from the ischemic areas at 2 days after MI but not at 2 and 4 weeks after MI. Ultrastructurally, typical apoptotic figures, including apoptotic bodies and condensed nuclei without ruptured plasma membranes, were detected in leukocytes from all hearts with 2-day MI and in myofibroblasts, endothelial cells, and macrophages from all hearts with 2-week MI. In the electron microscopic in situ nick end labeling, immunogold particles intensely labeled the condensed chromatin of the typical apoptotic nuclei. These particles were also accumulated on nuclei of the interstitial cells showing homogeneous density but not definite condensation as typical apoptotic nuclei, suggesting an early stage of apoptosis. Thus, apoptosis plays an important role in the disappearance of both the infiltrated leukocytes and the proliferated interstitial cells after MI. This finding may have therapeutic implications for postinfarct ventricular remodeling through apoptosis handling during the healing stage of MI.

Anti-tumor effect of gallic acid on LL-2 lung cancer cells transplanted in mice

We previously reported that gallic acid (3,4,5-trihydroxybenzoic acid), a naturally occurring plant phenol, can induce apoptosis in four kinds of human lung cancer cell lines in vitro. The present study further investigated the in vivo anti-tumor effects of orally administered gallic acid. Gallic acid reduced cell viability of LL-2 mouse lung cancer cells in vitro dose dependently, with a 50% inhibitory concentration (IC50) value of around 200 microM. C57Black mice were transplanted with LL-2 cells, and administered gallic acid (1 mg/ml in drinking water, ad libitum) and/or cisplatin (4 mg/kg i.p. injection, once a week). The average weight of the transplanted tumors, obtained at 29 days after transplantation, in the mice of control, gallic acid-treated cisplatin-treated and cisplatin plus gallic acid-treated groups was 4.02, 3.65, 3.19 and 1.72 g, respectively. The average tumor weight of the mice treated with cisplatin combined with gallic acid was significantly smaller than that of the control group (p<0.05). The amount of apoptotic cells in the tumor tissues of mice treated with gallic acid and/or cisplatin was significantly higher than those of the control mice. Combination of gallic acid and cisplatin increased the tumor cell apoptosis compared with the treatment with cisplatin alone. The present findings suggest that the combination of gallic acid with an anti-cancer drug, including cisplatin, may be an effective protocol for lung cancer therapy.

Plasma Fas ligand, an inducer of apoptosis, and plasma soluble Fas, an inhibitor of apoptosis, in patients with chronic congestive heart failure

OBJECTIVES

This study sought to examine plasma levels of soluble Fas/APO-1 receptor (sFas), an inhibitor of apoptosis, and soluble Fas ligand (sFas-L), an inducer of apoptosis, and their relation to each other and to other clinical variables, such as New York Heart Association functional class, tumor necrosis factor (TNF) and interleukin-6 (IL-6) in congestive heart failure (CHF).

BACKGROUND

It has been recently reported that apoptotic cell death occurs in myocytes of dogs with CHF. Hypoxia is frequently seen in advanced CHF and can stimulate Fas/APO-1 receptors (Fas) to induce apoptosis in cultured myocytes. Fas and Fas ligand (Fas-L) are cell-surface proteins and representative apoptosis-signaling molecules. Fas on the cell membrane induces apoptosis when it binds Fas-L or sFas-L. However, plasma sFas, a molecule lacking the transmembrane domain of Fas, blocks apoptosis by inhibiting binding between Fas and Fas-L or sFas-L on the cell membrane. At present, it is unknown whether plasma sFas-L and plasma sFas increase in the presence of cardiac disease.

METHODS

The study included 70 patients (mean [+/-SEM] age 65 +/- 2 years, range 21 to 93) with chronic CHF (coronary artery disease in 28, dilated cardiomyopathy in 27, valvular heart disease in 15) and 62 age- and gender-matched normal control subjects. Plasma levels of sFas, sFas-L, TNF-alpha and IL-6 were measured by enzyme-linked immunosorbent assays using monoclonal anti-human antibodies.

RESULTS

There was no significant difference in sFas-L levels between normal subjects and patients in functional classes I to IV; however, sFas increased with severity of functional classification, independent of the underlying disease. sFas levels were significantly higher even in patients in functional class II than in normal subjects and those in functional class I, and were highest in patients in functional class IV (normal subjects; 2.2 +/- 0.1 ng/ml; functional class I: 2.2 +/- 0.2 ng/ml; functional class II: 3.1 +/- 0.2 ng/ml; functional class III: 3.9 +/- 0.3 ng/ml; functional class IV: 5.1 +/- 0.6 ng/ml). Plasma sFas levels were significantly higher in patients with elevated pulmonary artery wedge pressure and a decresed cardiac index than in those with values in the normal range. In patients in functional class IV, there was no significant difference in plasma sFas levels between the survivors and non-survivors during 6-month follow-up. However, plasma levels of sFas tended to decrease in nine patients with clinical improvement (baseline sFas: 5.2 +/- 0.8 ng/ml; 6-month sFas: 4.3 +/- 0.5 ng/ml, p = 0.07) but were similar in patients with no change in functional class. TNF-alpha and IL-6 were increased significantly only in patients in functional class IV, as previously reported, but were not related to sFas.

CONCLUSIONS

We found elevated levels of plasma sFas and no increase in plasma sFas-L in human CHF. The increase in sFas may play an important role in the pathophysiologic mechanisms of CHF.

Noninvasive quantitative tissue characterization and two-dimensional color-coded map of human atherosclerotic lesions using ultrasound integrated backscatter: comparison between histology and integrated backscatter images

OBJECTIVES

The purpose of the present study was to define clinicopathologically whether integrated backscatter (IB) combined with conventional two-dimensional echo (2DE) can differentiate the tissue characteristics of calcification (CL), fibrosis (FI), lipid pool (LP) with fibrous cap, intimal hyperplasia (IH) and thrombus (TH) and can construct two-dimensional tissue plaque structure in vivo.

BACKGROUND

It is difficult to characterize the components of plaque using conventional 2DE techniques.

METHODS

Integrated backscatter values of plaques were measured in the right common carotid and femoral arteries (total 24 segments) both during life and after autopsy in 12 patients (age 68 to 84 years, 10 men and two women). Integrated backscatter values were determined using a 5-12 MHz multifrequency transducer, setting the region of interests (ROIs) (11 x 11 pixels) on the echo tomography of the entire arterial wall (55 +/- 10 ROI/segment) and comparing it with histologic features in the autopsied arterial specimens.

RESULTS

Corrected IB values obtained before death and at autopsy were significantly correlated (r = 0.93, p < 0.01). Corresponding to the histologic features, corrected IB values on the rectangle ROIs obtained during life were divided into five categories: category 1 (TH) 4 < IB < or = 6; category 2 (media and IH or LP in the intima) 7 < IB < or = 13; category 3 (FI) 13 < IB < or = 18, category 4 (mixed lesion) 18 < IB < or = 27 and category 5 (CL) 28 < IB < or = 33. In category 2, media and intima were differentiated using conventional 2DE. Under the above procedures, color-coded maps constructed with IB-2DE obtained during life precisely reflected the histologic features of media and intima.

CONCLUSIONS

Integrated backscatter with 2DE represents a useful noninvasive tool for evaluating the tissue structure of human plaque.

Three minute, but not one minute, ischemia and nicorandil have a preconditioning effect in patients with coronary artery disease

OBJECTIVES

This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans.

BACKGROUND

The ischemic PC effect is induced in 180 s ischemia, but not in 120 s ischemia in rabbit hearts. However, the duration of ischemia that induces PC effect and the role of the KATP channel in the PC effect in humans are still unclear.

METHODS

Forty-six patients with stable angina were randomly allocated to four groups: the duration of the first inflation as PC ischemia was 60 s in the PC60 group (n = 12), and 180 s in the PC180 group (n = 12). In the other groups, NC (80 microg/kg) was intravenously given for 1 min in the NC group (n = 12), and isosorbide dinitrate (ISDN) (40 microg/kg) was given in the ISDN group (n = 10). Five minutes after first inflation or drug administration, a second inflation was conducted for 120 s in each group. In the ECG, the lead with the largest shift in ST segment (deltaST max), and the sum of elevated ST levels in all leads (sigmaST) were determined.

RESULTS

In the PC60 group, no significant difference was observed in either deltaST max or sigmaST between the first and second inflation. However, the second inflation in the PC180 group showed significantly lower levels of deltaST max and sigmaST compared with those of the first inflation. In the NC group, both deltaST max and sigmaST measured at 30 s and 60 s after balloon inflation were significantly lower than those of the first inflation in the PC60 and PC180 control groups. In the ISDN group, no significant difference was observed in deltaST max or sigmaST.

CONCLUSION

In human PTCA models, a PC effect is observed in 180 s ischemia, but not in 60 s ischemia. A pharmacological PC effect is induced by NC, a KATP channel opener with a nitrate-like effect but not ISDN. This suggests that the opening of KATP channels plays an important role in the protecting effect of NC.

Process of progression of coronary artery lesions from mild or moderate stenosis to moderate or severe stenosis: A study based on four serial coronary arteriograms per year

BACKGROUND

The process of progression in coronary artery disease is unknown.

METHODS AND RESULTS

The subjects were 36 patients with 36 objective vessels with clinically significant progression of coronary artery disease (>/=15% per year) in whom 4 serial coronary arteriograms (CAGs) were performed at intervals of approximately 4 months in a 1-year period. The degree of progression of percent stenosis between each of 2 serial CAGs was classified as marked (M: >/=15%), slight (S: 5% to 14%), and no progression (N: <5%). From the pattern of progression, the 36 vessels were classified as 14 type 1 vessels with marked progression (N-->N-->M in 13 vessels and S-->S-->M in 1 vessel) and 22 type 2 vessels without marked progression (S-->S-->S in 18 vessels, N-->S-->S in 4). Percent stenosis at the first, second, third, and final CAGs was 44+/-14%, 46+/-13%, 46+/-13%, and 88+/-10% (P<0.05 versus first CAG) in type 1 vessels and 44+/-11%, 50+/-9%, 59+/-9%, and 67+/-9% in type 2 vessels (P<0.05 for second, third, and final CAGs versus first CAG). Type 1 vessels featured the sudden appearance of severe stenosis due to marked progression, angina pectoris, or myocardial infarction (71%) and Ambrose type II eccentric lesions indicating plaque rupture or thrombi (57%). Type 2 vessels featured continuous slight progression of stenosis with smooth vessel walls; angina pectoris (14%) occurred when the percent stenosis reached a severe level. An increase in serum C-reactive protein was observed only in the type 2 vessel group, which suggests a relation between continuous slight progression and inflammatory change.

CONCLUSIONS

Two types of stenosis progression provide a new insight into the mechanism of coronary artery disease.

Considerable time from the onset of plaque rupture and/or thrombi until the onset of acute myocardial infarction in humans: coronary angiographic findings within 1 week before the onset of infarction

BACKGROUND

It has been thought that the thrombi and bleeding in plaques that occur after plaque rupture or endothelial damage from vessels with mild stenosis suddenly occlude the lumen and cause acute myocardial infarction (AMI). However, our hypothesis is that thrombi and bleeding may not suddenly occlude the lumen.

METHODS AND RESULTS

The study group consisted of 20 patients who had coronary angiograms performed within 1 week (3+/-3 days) before AMI and 20 control patients who had coronary angiograms performed 6 to 18 months (282+/-49 days) before AMI. The features of infarct-related coronary segments (IRCS) at 3 days before AMI were the presence of a significant stenosis of >50% (95% in incidence and 71+/-12% diameter stenosis) and Ambrose's type II eccentric lesions (plus multiple irregularities), an indicator of plaque rupture and/or thrombi (60% [70%]), and the features at 1 year before AMI were mild stenosis of <50% (95% incidence and 30+/-18% diameter stenosis) with rare Ambrose's type II eccentric lesions (plus multiple irregularities) (10% [10%]). The same relation was observed in each of the 4 subgroups with Q-wave infarction, non-Q-wave infarction, preceding effort angina within 1 month before AMI, and no preceding effort angina.

CONCLUSIONS

The appearance of marked progression and Ambrose's type II eccentric lesion on coronary angiograms 3 days before AMI suggests the presence of a considerable time from the onset of plaque rupture and/or thrombi until the onset of AMI. These features may be predictors of AMI. The concept provides new insight into the mechanism and prevention of human AMIs.

An increase of soluble Fas, an inhibitor of apoptosis, associated with progression of COPD

In chronic obstructive pulmonary disease (COPD) which consists of emphysema and chronic bronchitis, alveolar tissue and/or bronchiolar walls are progressively destroyed. This suggests cell death by necrosis and/or apoptosis although no direct evidence of apoptosis has been reported. It was speculated that the apoptosis-related factors are associated with the progression of COPD. Fas/Apo-1 receptor (Fas), Fas ligand (Fas-L) and soluble Fas ligand (sFas-L) are inducers, while soluble Fas (sFas) is an inhibitor of apoptosis. In this study, plasma sFas and sFas-L were measured in 19 COPD patients receiving supplemental O2 (severe COPD) and 20 COPD patients not receiving supplemental O2 (mild/moderate COPD). Twenty-two age- and sex-matched healthy volunteers (healthy controls) and 20 patients receiving supplemental O2 and with level of hypoxaemia similar to severe COPD due to other pulmonary diseases (disease controls) were also examined. Plasma sFas-L was within normal limits in all groups. Plasma sFas levels were similar among healthy controls, disease controls, and mild/moderate COPD patients, but significantly increased in severe COPD (2.6 +/- 1.1, 2.6 +/- 0.2, 2.8 +/- 0.2 and 4.8 +/- 1.0 ng ml-1, respectively). Although PaO2 was lower in severe COPD than in mild/moderate COPD, and PaCO2 was higher in severe COPD than in mild/moderate COPD, they were close between severe COPD and disease controls. Tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and C-reactive protein (CRP) were increased in patients with COPD, but were similar in both severe and mild/moderate COPD patients. We conclude that increased plasma sFas, which is independent of hypoxaemia, and increases in PaCO2, TNF-alpha, IL-6 and inflammation, may be associated with progression of COPD.

Marked expression of plasma brain natriuretic peptide is a special feature of hypertrophic obstructive cardiomyopathy

OBJECTIVES

We examined whether plasma brain natriuretic peptide levels are abnormally elevated in hypertrophic obstructive cardiomyopathy compared with other cardiac diseases.

BACKGROUND

We previously reported that plasma brain and atrial natriuretic peptide levels were elevated in hypertrophic cardiomyopathy.

METHODS

We compared plasma concentrations of brain and atrial natriuretic peptide and hemodynamic and echocardiographic data in 50 patients with hypertrophic obstructive cardiomyopathy (n = 15, mean [+/-SD] intraventricular pressure gradient 37 +/- 16 mm Hg), hypertrophic nonobstructive cardiomyopathy (n = 15), aortic stenosis (n = 10, mean pressure gradient 41 +/- 18 mm Hg) and hypertensive heart disease (n = 10, mean systolic/diastolic blood pressure 203 +/- 16/108 +/- 11 mm Hg, respectively) and 10 normal subjects.

RESULTS

Plasma brain natriuretic peptide levels were higher in the hypertrophic obstructive cardiomyopathy group (397.1 +/- 167.8 pg/ml*) than in the hypertrophic nonobstructive cardiomyopathy (60.0 +/- 48.1 pg/ml*), hypertensive heart disease (53.9 +/- 31.4 pg/ml*), aortic stenosis (75.4 +/- 54.3 pg/ml*) and normal groups (9.8 +/- 6.4 pg/ml [*p < 0.05 vs. normal group, p < 0.05 vs. hypertrophic obstructive cardiomyopathy group]). Although plasma atrial natriuretic peptide levels were higher in the hypertrophic obstructive cardiomyopathy group than the other patient groups, the brain/atrial natriuretic peptide ratio in the hypertrophic obstructive cardiomyopathy group was higher (4.5 +/- 2.3) than those in the other three patient groups (1.1 to 1.4) and the normal group (0.7 +/- 0.5). Left ventricular end-diastolic pressure and left ventricular end-diastolic volume index were similar among the four patient groups. The interventricular septal thickness and the ratio of interventricular septal thickness to left ventricular posterior wall thickness were similar between the hypertrophic obstructive and nonobstructive cardiomyopathy groups.

CONCLUSIONS

Abnormal elevations of plasma brain natriuretic peptide levels are difficult to explain on the basis of hemodynamic and echocardiographic data and are a special feature of hypertrophic obstructive cardiomyopathy.

Evidence for the delayed effect in human ischemic preconditioning: prospective multicenter study for preconditioning in acute myocardial infarction

OBJECTIVES

This study aimed to investigate prospectively the protective effect of a first preinfarction angina attack against acute myocardial infarction (AMI) in human hearts without significant collaterals.

BACKGROUND

Several retrospective studies and the prospective studies have demonstrated the existence of the preconditioning (PC) effect in humans. However, collaterals were not examined in the prospective studies. In animal models, the PC effect on myocardial infarct size appears soon after PC reperfusion (classic) but disappears within 1 to 2 h. It then reappears 24 to 48 h after reperfusion (the delayed PC effect). Meanwhile, the PC effect on stunning appears 12 h after PC reperfusion (the delayed PC effect). The concept of the classic and delayed PC effects has not been investigated in human AMI studies. If the above concept is also correct in humans, the infarct size and/or impairment of the left ventricular function should be inversely correlated with the time interval between the first preinfarction angina attack and the onset of AMI when that time interval is limited to between 2 and 48 h.

METHODS

The subjects were 25 patients with first AMI of the proximal left anterior descending artery who underwent successful direct percutaneous transluminal coronary angioplasty (PTCA) 2 to 6 h after the onset and with no (or poor) collateral circulation (grade 0 or 1). They were divided into two groups: preinfarction angina (PA)(+) group: 11 patients with new onset preinfarction angina from 2 to 48 h before the onset, PA(-) group: 14 patients without angina before infarction. Peak creatine kinase (CK) and cumulative CK were examined, and the left ventricular ejection fraction (LVEF) and the regional wall motion (RWM) were determined from the left ventriculograms during the acute (immediately after the coronary reperfusion) and chronic (four weeks after the onset of AMI) phases. The RWM index (RWMI) was then calculated as the mean motion of chords (standard deviation [SD]/chord) lying in the area of chords of RWM < or = -2 SD in the acute phase (ischemic risk area). RESULTS The increase in the RWMI between the acute and chronic phases was significantly larger in the PA(+) group than in the PA(-) group (1.55 +/- 1.32 and 0.69 +/- 0.75, p < 0.05, respectively) although no significant difference in the enzymatic infarct size was seen between the two groups. The increases in the LVEF and the RWMI were significantly correlated with the time interval from the first preinfarction angina attack to the onset of AMI (r = 0.622, p < 0.05 and r = 0.646, p < 0.05, respectively), but the enzymatic infarct size was not.

CONCLUSIONS

The beneficial effect of preinfarction angina on left ventricular wall motion, independently of collateral flows, indicates the existence of the PC effect in humans. The greater protective effect of a longer time interval between angina pectoris and AMI suggests that the protection is due to a delayed PC effect.

Characterization of ultrastructure and its relation with DNA fragmentation in Fas-induced apoptosis of cultured cardiac myocytes

The purposes of the present study were to define precisely the ultrastructural features of apoptosis in cultured cardiomyocytes and to determine whether DNA fragmentation is essential for the apoptotic morphology. When cultured neonatal murine cardiomyocytes were incubated with an agonistic anti-Fas antibody in the presence of a non-toxic amount of actinomycin D or cycloheximide, approximately 70% of them had lost their viability after 24 h. The dead cardiomyocytes showed the typical ultrastructural changes of apoptosis on transmission and scanning electron microscopy, as well as by positive in situ nick end-labelling (TUNEL), positive Taq polymerase-based in situ ligation, a DNA ladder pattern on gel electrophoresis, and an increase in the active fragment of caspase-3. According to TUNEL at the electron microscopic level, apoptotic nuclear change, cytoplasmic shrinkage, and DNA fragmentation always occurred simultaneously in apoptotic cardiomyocytes. Other ultrastructural features of apoptosis were the appearance of abundant lipid-like structures in the cytoplasm of cardiomyocytes at the early phase, and a high incidence of plasma membrane rupture and formation of apoptotic bodies at the later phase. When zinc, an inhibitor of Ca2+/Mg2+-dependent endonuclease, was added to the present model, activation of caspase-3 and an apoptotic ultrastructure were still observed in spite of the lack of DNA fragmentation, indicating that this type of myocyte death is also apoptosis. In conclusion, the typical apoptotic ultrastructure and DNA fragmentation occur simultaneously in association with caspase-3 activation in Fas-stimulated cultured cardiomyocytes. Apoptotic morphology can, however, be observed even without DNA fragmentation.

Visualization of internal carotid artery atherosclerotic plaques in symptomatic and asymptomatic patients: a comparison of optical coherence tomography and intravascular ultrasound

BACKGROUND AND PURPOSE

OCT has been reported as a high-resolution imaging tool for characterizing plaque in the coronary arteries. The present study aimed to evaluate the ability of OCT to visualize carotid artery plaques compared with that of IVUS in asymptomatic and symptomatic patients.

MATERIALS AND METHODS

OCT was performed for 34 plaques (17 symptomatic, 17 asymptomatic) in 30 patients during CAS under a proximal cerebral protection method. OCT was performed before balloon angioplasty and after stent placement. IVUS was also performed just after OCT.

RESULTS

No technical or neurologic complications were encountered by using OCT. An inner catheter was used in 12 of 34 procedures (35.3%) for advancing the OCT image wire beyond the site of stenosis. OCT clearly visualized intraluminal thrombus in 15 of 34 plaques (44.1%), whereas IVUS detected a thrombus in 1 plaque (2.9%, P < .001). Neovascularization was demonstrated in 13 of 34 plaques (38.2%) by OCT, but not by IVUS (0%, P < .001). Intraluminal thrombus was more frequently observed in symptomatic plaques (13 of 17, 76.5%) than in asymptomatic plaques (2 of 17, 11.8%; P < .001). Interobserver and intraobserver variability with OCT diagnosis was excellent for thrombus, ulceration, neovascularization, and lipid pool.

CONCLUSIONS

The present findings suggest that OCT can safely and precisely visualize human carotid plaques during CAS and that intraluminal thrombus and neovascularization are more frequently detected in symptomatic plaques.

Nicorandil reduces myocardial infarct size by opening the K(ATP) channel in rabbits

We examined whether nicorandil reduces myocardial infarct size (1) when administered before ischemia, and (2) when administered before reperfusion, and whether (3) infarct size is influenced by the plasma nicorandil concentration and the opening of the K(ATP) channel. Anesthetized open-chest Japanese white male rabbits were subjected to a 30 min coronary occlusion (ischemia) and a 48 h reperfusion in the following six groups; Group 1 (n=9): control group, Group 2 (n=9): pre-ischemia to post-reperfusion group (nicorandil 10 microg/kg/min, i.v.), Group 3 (n=7): pre-ischemia to post-reperfusion+glibenclamide group (glibenclamide 0.3 microg/kg, i.v.+nicorandil 10 microg/kg/min, i.v.), Group 4 (n=8): pre-reperfusion to post-reperfusion group (nicorandil 10 microg/kg/min, i.v.), Group 5 (n=8): pre-ischemia low-dose group (nicorandil 10 microg/kg/min for 5 min i.v.), Group 6 (n=7): pre-ischemia high-dose group (nicorandil 100 microg/kg/min for 5 min i.v.). The plasma nicorandil concentrations were measured from blood samples taken immediately before the ischemia. After the 48 h reperfusion, the size of the infarct was measured histologically with immunohistochemical actin staining and expressed as a percentage of the area at risk.

RESULTS

Infarct sizes were as follows; Group 1 (control): 41.0+/-3.5%, Group 2: 31.3+/-2.0% (P<0.05 vs. control), Group 3: 40.9+/-3.4%, Group 4: 45.2+/-4.4%, Group 5: 35.8+/-3.3%, Group 6: 25.2+/-3.9% (P<0.05 vs. control). Infarct size was inversely correlated with the plasma nicorandil concentrations (y=-0.031x+41.0, r=0.65, P<0.05).

CONCLUSIONS

The pre-ischemic but not post-ischemic administration of nicorandil reduced the size of myocardial infarct by opening the K(ATP) channels, and this effect was dependent on the plasma nicorandil concentrations immediately before the ischemia induced in rabbits.

Highly sensitive ELISA for soluble Fas in serum: increased soluble Fas in the elderly

We have developed and characterized a highly sensitive ELISA for soluble Fas (sFas) in the serum. The linearity of calibrator range was 0.06-2.00 micrograms/L and the detection limit was 0.01 microgram/L. The average within- and between-run CVs were 3.9% and 3.8%, respectively. The recovery of added sFas to serum was 93-118%. The effects of possible interferences (tryglyceride, hemoglobin, bilirubin) were negligible. We determined serum sFas in 155 healthy subjects, ages 20-69. The mean value of sFas in men (2.50 +/- 0.63 micrograms/L, n = 78) was significantly higher than that in women (2.01 +/- 0.53 micrograms/L, n = 77) (P &lt; 0.001). Furthermore, there was a significant correlation between serum sFas concentration and age (men, r = 0.397, P &lt; 0.001; women, r = 0.569, P &lt; 0.001). Although the concentrations of sFas tended to increase with aging, it remains to be clarified how Fas-mediated apoptosis relates to aging.

Dynamic process of apoptosis in adult rat cardiomyocytes analyzed using 48-hour videomicroscopy and electron microscopy: beating and rate are associated with the apoptotic process

Dynamic process of apoptosis has not been elucidated in adult rat cardiomyocytes. Soluble Fas ligand (0.1 microg/ml) in the presence of actinomycin D (0.05 microg/ml) induced apoptosis in cultured adult rat cardiomyocytes, as documented by activated caspase-3, DNA fragmentation, and apoptotic ultrastructure. In the present model, we observed 60 adult cardiomyocytes with a normal rod shape under a real-time videomicroscope continuously for 48 hours. Seventeen cells (28%) were unchanged and 7 cells (12%) showed oncosis (so-called necrosis) in which no beating was evident. In the remaining 36 cells (apoptosis, 60%), a slow beating (17 +/- 3/min) was initiated 16 +/- 1 hours later. Approximately 1 hour later, the rod cells showed long-axial shortening as bone- or club-like, or square-shaped, accompanied with faster beating rates (35 +/- 7/min). In 29 cells (type A1 and A2), marked shrinkage occurred; the cellular shape became almost completely round with a smooth surface and the beating ceased 3.0 +/- 0.4 hours later. Then, smooth budding appeared 0.6 +/- 0.2 hours later. Apoptotic bodies were found in 8 cells 10 +/- 4 hours later (type A1, 13%) but not in 21 cells (type A2, 35%). In the other 7 cells (type A3, 12%), the cell surface became rough 8 +/- 3 hours later and the beating ceased. Maximal beating rate was greatest in type A1 (72 +/- 26/min) and greater in type A2 (29 +/- 5/min) than in type A3 (10 +/- 2/min). Electron microscopy confirmed apoptotic ultrastructure even in the cardiomyocytes with bone-, club-like, or square shapes, suggesting that type A3 as well as A1 and A2 is also under apoptotic process. A caspase inhibitor, zVAD.fmk, blocked beating, apoptotic morphology, and DNA fragmentation, indicating these depended on caspase activation. In the caspase-dependent apoptotic process of cultured adult cardiomyocytes, beating and the following deformity of the cellular edges were the initial signs and the rate of beating was related with the subsequent three different processes of apoptosis.

Milrinone inhibits sympathetic-mediated tachycardia by a postjunctional action independent of cyclic AMP

In pithed rats with stimulated sympathetic outflow, the phosphodiesterase inhibitor milrinone (0.3 mg/kg, i.v.) decreased the peak tachycardiac response produced by both sympathetic nerve stimulation (15 s at 0.5-3 Hz) and norepinephrine administration (0.3-5 micrograms/kg, i.v.). However, another phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX, 0.5 mg/kg, i.v.) had no effect on the peak tachycardic response to sympathetic stimulation. Similarly, in isolated rat atria, milrinone (9 mumol/L) inhibited the tachycardia produced by norepinephrine, whereas IBMX (1 mumol/L) had no effect. The inhibitory effect of milrinone on sympathetic responses was not due to changes in norepinephrine release since milrinone (9 mumol/L) increased norepinephrine release in isolated rat atria incubated with [3H]norepinephrine. When the duration of the tachycardia (rather than the peak tachycardic response) produced by sympathetic nerve stimulation was measured, it was found to be prolonged by both milrinone and IBMX, suggesting that in this case cyclic AMP was involved. Furthermore, in contrast to its inhibitory effects on norepinephrine-induced tachycardia in rat atria, milrinone enhanced the tachycardia produced by the adenylate cyclase activator forskolin. These results suggest that milrinone has complex actions on sympathetic control of heart rate and that beta-adrenoceptor tachycardia occurs by mechanisms dependent on and independent of cyclic AMP.

Infarct size-reducing effect of ischemic preconditioning is related to alpha1b-adrenoceptors but not to alpha1a-adrenoceptors in rabbits

In rabbits and rats, both stimulation of alpha-adrenoceptors and ischemic preconditioning (PC) reduce infarct size. Activation of alpha1b-adrenoceptors play an important role in the PC effect on ventricular function in rats. However, the alpha1-adrenoceptors have not been reported to be related to the PC effect in rabbits, because the infarct size-reducing effect of PC is not blocked by the nonselective alpha-adrenoceptor antagonist, phenoxybenzamine (POB) or by the alpha1-adrenoceptor antagonist, BE2254. However, we speculated that alpha1b-adrenoceptors but not alpha1a-adrenoceptors may be related to the infarct size-reducing effect of PC in rabbit hearts. Thus we examined in rabbits whether the alpha1b-adrenoceptor blocker chloroethylclonidine (CEC), the alpha1a-adrenoceptor blocker 5-methylurapidil (5-MU), the selective alpha1-adrenoceptor antagonist bunazosin (BN), and the nonselective apha-adrenoceptor antagonist phenoxybenzamine (POB) can block the PC effect on infarct size. Eighty-eight anesthetized open-chest Japanese white male rabbits were subjected to 30-min coronary occlusion and 48-h reperfusion. In five PC groups, the rabbits were subjected to a single 5-min occlusion and 5-min reperfusion before 30-min sustained ischemia. In the PC groups, those with CEC (3 mg/kg, n = 10), 5-MU (3 mg/kg, n = 10), BN (0.3 mg/kg, n = 10), POB (4 mg/kg, n = 10), or placebo saline (n = 10) were pretreated before PC. In the non-PC groups, those with CEC (3 mg/kg, n = 7), 5-MU (3 mg/kg, n = 7), BN (0.3 mg/kg, n = 7), POB (4 mg/kg, n = 7), or placebo saline (n = 10) were pretreated before 30-min sustained ischemia. After a 48-h reperfusion, the infarct size was measured histologically and expressed as a percentage of the area at risk. PC caused a marked reduction of infarct size as compared with the non-PC control (10 +/- 3% vs. 42 +/- 2%; p < 0.05). The PC effect was completely blocked by CEC (36 +/- 2%) and by BN (42 +/- 4%) but not by 5-MU (14 +/- 1%) or POB (13 +/- 2%). None of the drugs by itself affected the infarct size. Stimulation of alpha1b-adrenoceptors but not of alpha1a-adrenoceptors during PC plays an important role in the PC effect on infarct size. This may explain the previous confusion concerning the PC blocking effect of various alpha1-blockers.

A novel anti-diabetic drug, miglitol, markedly reduces myocardial infarct size in rabbits

1. We examined whether N-hydroxyethyl-1-deoxynojirimycin (miglitol), a new human anti-diabetic drug with effects to inhibit alpha-1, 6-glucosidase glycogen debranching enzyme and reduce the glycogenolytic rate as well as to inhibit alpha-1,4-glucosidase, could reduce infarct size in the rabbit heart. Rabbits were subjected to 30-min coronary occlusion followed by 48-h reperfusion. 2. The infarct size as a percentage of area at risk was not reduced by pre-ischaemic treatment with 1 mg kg(-1) miglitol (42.7+/-4.0%, n=10) compared with the saline control group (41.7+/-2.3%, n=10). However, it was significantly and dose-dependently reduced by pre-ischaemic treatment with 5 or 10 mg kg(-1) of miglitol (25.7+/-4. 5%, n=10, and 14.6+/-2.4%, n=10, respectively) without altering the blood pressure, heart rate or blood glucose level. However, there was no evidence of an infarct-size reducing effect after pre-reperfusion treatment with 10 mg kg(-1) of miglitol (35.0+/-3.0%, n=10). 3. Another 40 rabbits given 1, 5 and 10 mg kg(-1) of miglitol or saline before ischaemia (n=10 in each) were sacrificed at 30 min of ischaemia for biochemical analysis. Miglitol preserved significantly the glycogen content, and attenuated significantly the lactate accumulation in a dose dependent manner in the ischaemic region at 30 min of ischaemia. 4. Pre-ischaemic treatment, but not pre-reperfusion treatment, with miglitol markedly reduced the myocardial infarct size, independently of blood pressure and heart rate. A dose-dependent effect of miglitol on infarct size, glycogenolysis and lactate formation suggests that the mechanism may be related to the inhibition of glycogenolysis. Thus, miglitol may be beneficial for coronary heart disease as well as diabetes mellitus.

Apoptosis and overexpression of bax protein and bax mRNA in smooth muscle cells within intimal hyperplasia of human radial arteries : analysis with arteriovenous fistulas used for hemodialysis

There is a type of arteriosclerosis with remodeling of middle-size arteries in which intimal hyperplasia of smooth muscle cells (SMCs) plays the main role, and there are few macrophages, T lymphocytes, and foam cells. It is unknown whether apoptosis and the expression of Bax, an inducer of apoptosis, are increased according to the progression of this type of human arteriosclerosis, which is different from so-called atherosclerosis. Bax heterodimerizes with Bcl-2, an inhibitor of apoptosis, and the ratio of Bax to Bcl-2 determines cellular apoptosis or survival. Thus, we investigated apoptosis and the expressions of Bax, bax mRNA, and Bcl-2 in human arteriovenous (AV) fistulas used for hemodialysis, a representative of arteriosclerosis of the aforementioned type. The material was 20 radial arteries obtained from 20 patients with chronic renal failure undergoing AV shunt surgery. SMCs, macrophages, and T lymphocytes were immunohistochemically identified at the light microscopic (LM) level. Apoptosis was detected by in situ terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-dUTP nick end labeling (TUNEL) at both the LM and electron microscopic (EM) level. Cell proliferating activity was estimated by proliferating cell nuclear antigen (PCNA). Bax and Bcl-2 were detected by immunohistochemistry and Western blot analysis. Expression of bax mRNA was detected by in situ hybridization. LM TUNEL-positive cells in both the intima and media were significantly increased according to the percent stenosis of the vessels. EM analysis revealed that ultrastructures of apoptotic SMCs were seen in both synthetic and contractile phenotypes. Their frequency of occurrence in the intima and media were greater in those vessels with >50% stenosis than in those with <50% stenosis (5.2+/-0.7% versus 1.0+/-0.3% in the intima and 2. 1+/-0.5% versus 0.2+/-0.1% in the media). The proportion of apoptotic SMCs with ruptured plasma membranes was greater than that of apoptotic SMCs with intact membranes in the intima of the former (4.1+/-0.6% versus 1.1+/-0.1%). Only those SMCs with apoptotic ultrastructures had TUNEL-positive nuclei with moderate or marked accumulation of immunogold particles at the EM level. However, ultrastructures of oncosis (primary necrosis) were not observed. Immunohistochemical analyses showed significant positive correlations between percent stenosis of vessels and the percentage of either PCNA-positive intimal cells or Bax-positive areas in the intima and media. Bcl-2-positive cells were not observed in the intima but mainly in the outer media. The percentage of Bcl-2-positive medial cells was definitely decreased at an early stage after formation of the AV fistula but did not change according to the duration of hemodialysis or the progression of arteriosclerosis. Western blot analysis of Bax or Bcl-2 and in situ hybridization of bax mRNA confirmed the immunohistochemical data. Thus, regulation of cellularity in intimal hyperplasia of SMCs in human arteriosclerosis with remodeling is mediated by proliferation and apoptosis but not oncosis. The apoptosis is probably induced by an increase in the Bax to Bcl-2 ratio.

Gallic acid induces vascular smooth muscle cell death via hydroxyl radical production

In the present study, we investigated whether gallic acid (GA) can induce death in cultured vascular smooth muscle cells (VSMCs), and whether production of the hydroxyl radical (.OH) is involved in the process of GA action. GA killed cultured VSMCs from rat aorta, in a dosc- and time-dependent manner. Cytoplasmic shrinkage and nuclear condensation were observed light microscopically in GA-treated VSMCs, which appeared apoptotic. However, the ultrastructure of the VSMC was not typical of apoptosis: nuclear condensation was not glossy, and the plasma membrane and subccellular organelles were disrupted. Although the VSMC were positive for in situ nick end-labeling (TUNEL). they did not show a DNA ladder pattern on gel electrophoresis and were negative for T aq polymerase-based in situ ligation, which is more specific for apoptosis than TUNEL. Moreover. GA-induced cell death was not prevented by Boc-Asp-fmk (a pan-caspase inhibitor). Production of OH was detected in GA-treated VSMCs using high-performance liquid chromatography with salicylic acid as a trapping agent. Lipid peroxidation was also observed. The production of .OH was inhibited by catalase (CAT) and deferoxamine (DFX), and these treatments completely rescued VSMCs from cell death. In a cell-free system, GA produced .OH in the presence of Fe2+-EDTA, which was quenched by CAT and DFX, suggesting involvement of the Haber-Weiss reaction. Oxidative stress by reactive oxygen species, .OH in particular, is one of the mechanisms of GA-induced death of VSMCs, the mode of which was different from typical apoptosis.

Plasma soluble fas and soluble fas ligand in chronic glomerulonephritis

It has been reported that glomerular cells with apoptosis and positive Fas immunoreactivity are seen in proliferative glomerulonephritis (PGN). Fas induces apoptosis when it binds to Fas ligand (Fas-L) or soluble Fas-L (sFas-L). However, soluble Fas (sFas) blocks apoptosis by inhibiting binding between Fas and Fas-L or sFas-L. That is, Fas, Fas-L, and sFas-L are inducers of apoptosis, but sFas is an inhibitor of apoptosis. We studied the relationship between the plasma levels of sFas and sFas-L in 32 patients with various types of adult chronic glomerulonephritis. Patients with serum creatinine levels >1.5 mg/dl (132.6 micromol/l) were excluded. The plasma levels of sFas-L were within the normal limits in all patients. The plasma levels of sFas in the patients with minimal-change (n = 8) and membranous nephropathy (n = 7) were similar to the age- and sex-matched controls. However, the plasma sFas levels were significantly elevated in patients with mesangial PGN (n = 10) and membranoproliferative glomerulonephritis (n = 7)(3. 4 +/- 0.9 and 3.9 +/- 1.5 ng/ml, respectively) as compared with the age- and sex-matched controls (controls: 2.1 +/- 0.4 and 2.2 +/- 0.6 ng/ml, respectively). In PGN, according to increase of histological grade and decrease of creatinine clearance, the number of TUNEL-positive cells in glomeruli is decreased in spite of an increase of the Fas positivity, and plasma sFas is increased. The degree of proliferative change is determined by the balance between proliferation and apoptosis and/or necrosis. Therefore, increased plasma sFas in PGN may inhibit apoptosis in glomeruli and may be one of the progressing factors in PGN. Thus, we conclude that an increase in plasma sFas levels is important to the protection of apoptosis in PGN.

Caspase-dependent and serine protease-dependent DNA fragmentation of myocytes in the ischemia-reperfused rabbit heart: these inhibitors do not reduce infarct size

Some infarcted myocytes undergo caspase-dependent DNA fragmentation, but serine protease-dependent DNA fragmentation may also be involved. There is controversy regarding whether caspase inhibitors can reduce infarct size, so the present study investigated whether serine protease inhibitor can reduce the DNA fragmentation of infarcted myocytes and whether serine protease or caspase inhibitors attenuates myocardial infarct size in Japanese white rabbits without collateral circulation. Rabbits were subjected to 30-min coronary occlusion followed by 48-h reperfusion. A vehicle (dimethylsulfoxide, control group, n=8) or Z-Val-Ala-Asp(Ome)-CH2F (ZVAD-fmk, a caspase inhibitor, ZVAD group, 0.8 mg/kg iv at 20 min before coronary occlusion and 0.8 mg/kg at 90 min after reperfusion, n=8) or 3,4-dichloroisocoumarin (DCI, a serine protease inhibitor, 2 mg/kg iv at 20 min before coronary occlusion, DCI group, n=8) was administered. Animals were killed at 48h after reperfusion for the detection of myocardial infarct size and at 4h after reperfusion for the detection of dUTP nick end-labeling (TUNEL)-positive myocytes, the electrophoretic pattern of DNA fragmentation and ultrastructural analysis. The left ventricle (LV) was excised and sliced. The myocardial infarct size as a percentage of the area at risk was assessed by triphenyltetrazolium chloride staining. DNA fragmentation was assessed by in situ TUNEL at the light microscopic level. ZVAD and DCI significantly reduced the mean blood pressure during reperfusion without affecting heart rate. There was no significant difference in the % area at risk (AAR) of LV among the 3 groups (control: 26.3+/-3.0%; ZVAD: 25.6+/-2.6%; DCI: 25.6+/-2.0%). The % infarct size as a percentage of the AAR in the ZVAD group (41.3+/-4.5%) and the DCI group (50.4+/-3.8%) was not significantly different from the control group (43.5+/-4.5%). However, the percent DNA fragmentation in the infarcted area in the ZVAD (3.5+/-0.8%) and DCI groups (4.2+/-0.9%) was significantly reduced compared with the control group (10.7+/-1.9%). The DNA ladder pattern observed in the control group was attenuated in both the ZVAD and DCI groups. There was no difference in electron microscopic changes among the 3 groups. Serine protease-dependent DNA fragmentation is present in infarcted myocytes, in addition to caspase-dependent DNA fragmentation, but an infarct-size reducing effect was not observed with either of these inhibitors.