Presence of Severe Stenosis in Most Culprit Lesions of Patients with ST-segment Elevation Myocardial Infarction / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Previous studies revealed that culprit vessels of ST-segment elevation myocardial infarction (STEMI) were often related to mild or moderate stenosis. However, recent studies suggested that severe stenosis was primarily found in culprit lesions. The objective of this study was to analyze the stenosis severity of culprit lesions in STEMI patients and to clarify the paradoxical results.</p><p><b>METHODS</b>A total of 489 consecutive STEMI patients who underwent primary percutaneous coronary intervention were retrospectively studied from January 2012 to December 2014. The patients were divided into three groups based on stenosis severity using quantitative coronary analysis: Group A, 314 cases, stenosis ≥70%; Group B, 127 cases, stenosis 50-70%; and Group C, 48 cases, stenosis ≤50%. The clinical, demographic, and angiographic data of all groups were analyzed.</p><p><b>RESULTS</b>Patients in Group A exhibited a significantly higher prevalence of history of angina pectoris (95.9% vs. 62.5%, P< 0.001), multivessel disease (73.2% vs. 54.2%, P = 0.007), and lower cardiac ejection fraction (53.3 ± 8.6 vs. 56.8 ± 8.4, P= 0.009) than those in Group C. Multivariable analysis revealed that history of angina pectoris (odds ratio [OR]: 13.89, 95% confidence interval [CI]: 6.21-31.11) and multivessel disease (OR: 2.32, 95% CI: 1.25-4.31) were correlated with severe stenosis of the culprit lesion in Group A.</p><p><b>CONCLUSIONS</b>Most culprit lesions in STEMI patients were severe stenosis. These patients exhibited a higher prevalence of angina history and multivessel diseases.</p>

Probucol attenuates atrial autonomic remodeling in a canine model of atrial fibrillation produced by prolonged atrial pacing / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>We hypothesize that increased atrial oxidative stress and inflammation may play an important role in atrial nerve sprouting and heterogeneous sympathetic hyperinnervation during atrial fibrillation (AF). To test the hypothesis, we examined whether the antioxidant and anti-inflammatory treatment with probucol attenuates atrial autonomic remodeling in a canine model of AF produced by prolonged rapid right atrial pacing.</p><p><b>METHODS</b>Twenty-one dogs were divided into a sham-operated group, a control group and a probucol group. Dogs in the control group and probucol group underwent right atrial pacing at 400 beats per minute for 6 weeks, and those in the probucol group received probucol 1 week before rapid atrial pacing until pacing stopped. After 6-week rapid atrial pacing, general properties including left atrial structure and function, atrial hemodynamics and the inducibility and duration of AF were measured in all the groups. Atrial oxidative stress markers and serum C-reactive protein (CRP) concentration were estimated. The degree of nerve sprouting and sympathetic innervation at the right atrial anterior wall (RAAW) and the left atrial anterior wall (LAAW) were quantified by immunohistochemistry, atrial norepinephrine contents were also detected. Atrial beta-nerve growth factor (beta-NGF) mRNA and protein expression at the RAAW and LAAW were assessed by real-time quantitative RT-PCR and Western blotting respectively.</p><p><b>RESULTS</b>Atrial tachypacing induced significant nerve sprouting and heterogeneous sympathetic hyperinnervation, and the magnitude of nerve sprouting and hyperinnervation was higher in the RAAW than in the LAAW. Atrial beta-NGF mRNA and protein levels were significantly increased at the RAAW and LAAW, and the upregulation of beta-NGF expression was greater at the RAAW than at the LAAW in the control group. The beta-NGF protein level was positively correlated with the density of sympathetic nerves in all groups. Probucol decreased the increase of CRP concentration and attenuated atrial oxidative stress caused by atrial tachypacing. In addition, probucol could effectively inhibit atrial beta-NGF upregulation, significantly attenuate atrial nerve sprouting and heterogeneous sympathetic hyperinnervation, and dramatically reduce the inducibility and duration of AF.</p><p><b>CONCLUSIONS</b>The atrial over-expression of beta-NGF possibly caused by increased oxidative stress and inflammation may be the main mechanism underlying atrial autonomic remodeling during AF. Probucol attenuates atrial autonomic remodeling possibly by its antioxidant and anti-inflammatory actions.</p>

Calpain I inhibition prevents atrial structural remodeling in a canine model with atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Atrial fibrillation (AF) is accompanied by atrial structural remodeling. Calpain activity is induced during AF. To test a causal relationship between calpain activation and atrial structural changes, N-acetyl-Leu-Leu-Met (ALLM), a calpain inhibitor, was utilized in a canine AF model.</p><p><b>METHODS</b>Fifteen dogs were randomly divided into 3 groups: sham-operated group, control group and calpain inhibitor group; each with 5 dogs. Sustained AF was induced by rapid right atrium pacing at 600 beats per minute for 3 weeks. ALLM was administered at a dosage of 1.0 mg x kg(-1) x d(-1) in the calpain inhibitor group. Three weeks later, the proteolysis, protein expression of TnT and myosin, calpain I localization and expression and structural changes were examined in left atrial free walls, right atrial free walls and the interatrial septum respectively. Atrial size and contractile function were also measured by echocardiography.</p><p><b>RESULTS</b>Long-term rapid atrial pacing induced marked structural changes such as enlarged atrial volume, myolysis, degradation of TnT and myosin, accumulation of glycogen and changes in mitochondrial shape and size, which were paralleled by an increase in calpain activity. The positive correlation between calpain activity and the degree of myolysis (r(s) = 0.90 961, P < 0.0001) was demonstrated. In addition to structural abnormalities, pacing-induced atrial contractile dysfunction was observed in this study. The pacing-induced atrial structural alterations and loss of contractility were partially prevented by the calpain inhibitor ALLM.</p><p><b>CONCLUSIONS</b>Activation of calpain represents key features in the progression towards overt structural remodeling. Calpain inhibitor, ALLM, suppressed the increased calpain activity and reversed structural remodeling caused by sustained atrial fibrillation in the present model. Calpain inhibition may therefore provide a possibility for therapeutic intervention in AF.</p>

Calpain I inhibition prevents pacing-induced structural remodeling for atrial fibrillation in canine / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the relation of the structural remodeling processes and activation of calpain I.</p><p><b>METHODS</b>Fifteen dogs were randomly divided into three groups. The dogs in pacing group (n=5) and inhibitor group (n=5) were subjected to 3 weeks of rapid atrial pacing at 600 beats/min, control dogs (n=5) were in sham-operated group. The dogs in inhibitor group were administered intravenous N-Acetyl-Leu-Leu-Met (ALLM), a calpain inhibitor, and in pacing group and sham-operated group were administered intravenous DMSO. The activity of calpain I was measured by hydrolyzing Suc-Leu-Leu-Val-Tyr-7-amino-4-methyl-coumarin. The ultrastructure of atrium was examined by light and electron microscopy. TnT expression was assessed by Western blot. Echocardiography examination was performed in all the three groups.</p><p><b>RESULTS</b>Calpain I activity was significantly increased in pacing group (2.3-fold, P<0.01), and decreased in inhibitor group (1.1-fold, P>0.05), compared to sham-operated group respectively. The percentages of myolysis were (76.7 +/- 5.9)% and (20.8 +/- 8.1)% in pacing group and inhibitor group respectively (P<0.01). TnT expression decreased in the rapid pacing-induced persistent atrial fibrillation, and these effects were inhibited by calpain I inhibitor ALLM. The area and volume of left atrium tended to increase after 3 weeks ALLM treatment in inhibitor group, but the change was not as prominent as in pacing group (P<0.05).</p><p><b>CONCLUSIONS</b>ALLM can decrease calpain I activity, and prevent canine atrial cardiomyocyte structural remodeling during atrial fibrillation. This study provided a capacity of atrial cardiomyocyte protection.</p>