Ischaemic cardiomyopathy. Pathophysiological insights,diagnostic management and the roles of revascularisation and device treatment. Gaps and dilemmas in the era of advanced technology

Ischaemic cardiomyopathy (ICM) represents an important cardiovascular condition associated with substantially increased morbidity and mortality. It is characterised from a broad spectrum of clinical manifestations and pathophysiological substrates and its diagnosis is based on the demonstration of significant left ventricular dysfunction in the context of significant epicardial coronary artery disease. Contemporary management aims at improving prognosis through evidence‐based pharmacotherapy and device therapy, where indicated. Whilst the beneficial role of revascularisation remains clear in patients with strong indications such as those with symptoms and/or acute coronary syndromes, for those patients that are asymptomatic and suffer from stable ischaemic heart disease the impact of revascularisation on hard outcomes remains less well defined and currently its adoption is hampered by the lack of robust randomised data. The aim of this review is therefore to provide a constructive appraisal on the pathophysiology of ICM, the role of the various non‐invasive imaging techniques in the diagnosis of ICM and the differentiation between viable and non‐viable myocardium and finally discourse the potential role of revascularisation and contemporary device therapy in the management of patients with ICM.     

The number of cardiac myocytes in the hypertrophic and hypotrophic left ventricle of the obese and calorie-restricted mouse heart

Changes in body mass due to varying amounts of calorie intake occur frequently with obesity and anorexia/cachexia being at opposite sides of the scale. Here, we tested whether a high-fat diet or calorie restriction (CR) decreases the number of cardiac myocytes and affects their volume. Ten 6–8-week-old mice were randomly assigned to a normal (control group, n = 5) or high-fat diet (obesity group, n = 5) for 28 weeks. Ten 8-week-old mice were randomly assigned to a normal (control group, n = 5) or CR diet (CR group, n = 5) for 7 days. The left ventricles of the hearts were prepared for light and electron microscopy, and analysed by design-based stereology. In CR, neither the number of cardiac myocytes, the relationship between one- and multinucleate myocytes nor their mean volume were significantly different between the groups. In contrast, in the obese mice we observed a significant increase in cell size combined with a lower number of cardiomyocytes (P < 0.05 in the one-sided U-test) and an increase in the mean number of nuclei per myocyte. The mean volume of myofibrils and mitochondria per cardiac myocyte reflected the hypertrophic and hypotrophic remodelling in obesity and CR, respectively, but were only significant in the obese mice, indicating a more profound effect of the obesity protocol than in the CR experiments. Taken together, our data indicate that long-lasting obesity is associated with a loss of cardiomyocytes of the left ventricle, but that short-term CR does not alter the number of cardiomyocytes.     

Heart wall myofibers are arranged in minimal surfaces to optimize organ function

Heart wall myofibers wind as helices around the ventricles, strengthening them in a manner analogous to the reinforcement of concrete cylindrical columns by spiral steel cables [Richart FE, et al. (1929) Univ of Illinois, Eng Exp Stn Bull 190]. A multitude of such fibers, arranged smoothly and regularly, contract and relax as an integrated functional unit as the heart beats. To orchestrate this motion, fiber tangling must be avoided and pumping should be efficient. Current models of myofiber orientation across the heart wall suggest groupings into sheets or bands, but the precise geometry of bundles of myofibers is unknown. Here we show that this arrangement takes the form of a special minimal surface, the generalized helicoid [Blair DE, Vanstone JR (1978) Minimal Submanifolds and Geodesics 13-16], closing the gap between individual myofibers and their collective wall structure. The model holds across species, with a smooth variation in its three curvature parameters within the myocardial wall providing tight fits to diffusion magnetic resonance images from the rat, the dog, and the human. Mathematically it explains how myofibers are bundled in the heart wall while economizing fiber length and optimizing ventricular ejection volume as they contract. The generalized helicoid provides a unique foundation for analyzing the fibrous composite of the heart wall and should therefore find applications in heart tissue engineering and in the study of heart muscle diseases.     

Effect of synthetic dermorphin analogues on tissue homeostasis in the myocardium of newborn albino rats

DNA synthesis and state of the nucleolar apparatus in myocardial cells of newborn albino rats receiving intraperitoneal injection of sedatin, a synthetic dermorphin analogue, were studied by means of autoradiography and silver impregnation. Labeling intensity significantly increased, while the number of nucleoli in nuclei decreased. Chemiluminescence study showed that the concentration of reactive oxygen metabolites significantly decreased in the myocardium of treated animals after sedatin administration. Non-arginine analogue of sedatin had little effect on tissue homeostasis in the myocardium. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 10, pp. 413–416, October, 2007     

心肌及蛛网膜下腔NGF基因转染对1型糖尿病大鼠心脏损伤的保护作用

目的 探讨以重组腺相关病毒（rAAV）为载体,评价心肌点注射和蛛网膜下腔注射转导神经生长因子（NGF）基因对1型糖尿病大鼠心脏损伤的保护作用。方法 全实验包括两个子实验。实验一：将12只SPF级雄性SD大鼠采用随机数字表法分为2组（n=6）：对照组、糖尿病（DM）组,DM组大鼠通过注射链脲佐菌素（STZ）建立1型糖尿病模型,2组大鼠于注射STZ前1 d及后第1、2、4、6、8、9周测甩尾反射潜伏期,并在第9周时通过酶联免疫吸附试验（ELISA）检测各组织中的NGF、降钙素基因相关肽（CGRP）含量。实验二：24只SPF级雄性SD大鼠随机分为4组（n=6）：糖尿病心脏转染对照组（MC）组、糖尿病心脏转染（ME）组、糖尿病脊髓转染对照（SC）组、糖尿病脊髓转染（SE）组,采用2×2析因设计,4组糖尿病模型建模方法同DM组,成模后第4周,MC组和ME组以心脏点注射分别转染滴度为0.8×1013 μg/L携带绿色荧光蛋白（GFP）基因的重组腺相关病毒（rAAV9-GFP）和相同滴度的携带NGF基因的rAAV-GFP（rAAV9-NGF-GFP）,各100 μL;SC组和SE组以蛛网膜下腔注射分别转染滴度为0.8×1012 μg/L的rAAV2-GFP和相同滴度的rAAV2-NGF-GFP,各25 μL。5周后,测各组大鼠心功能指标。取心肌、T1-T5段脊髓及背根神经节组织,荧光显微镜下观察GFP的表达情况;采用ELISA测各组织中的NGF、CGRP含量。结果 实验一中,与对照组相比,DM组的甩尾反射潜伏期在第4周后明显延长（P＜0.05）,心肌组织中的NGF、CGRP明显下调（P＜0.05）。实验二中,心肌点注射法转染rAAV9-NGF-GFP可改善大鼠的各项心功能指标（P＜0.05）,上调心肌组织中NGF、CGRP蛋白含量（P＜0.05）;且实验过程中的转染物与转染途径之间存在交互效应,两者联用改善心功能和上调心肌组织中NGF、CGRP的效果更显著（P＜0.05）。结论 心肌点注射rAAV-NGF-GFP可以更有效地提高1型糖尿病大鼠心肌组织中NGF的表达,产生更有效的心脏保护作用。     

七氟烷对心肌缺血再灌注内皮细胞细胞间黏附分子-1、血管细胞黏附分子-1和E-选择素表达的影响

目的： 探讨七氟烷对心肌缺血再灌注内皮细胞促炎作用的细胞间黏附分子-1（ ICAM-1）、血管细胞黏附 分子-1（ VCAM-1）和E- 选择素表达的影响。方法 ：在大鼠心肌缺血再灌注模型的基础上,将大鼠随机分为假 手术组（ 对照组）、缺血再灌注损伤组（ I/R 组）和七氟烷组;观察各组大鼠手术前、缺血15 min 和再灌注4 h 的 心率、平均动脉压和心率-收缩压乘积（ RPP ）;免疫组织化学法检测心肌组织中CD68+ 巨噬细胞数目、内皮细胞 ICAM-1、VCAM-1 和E- 选择素的表达;TUNEL 染色法检测凋亡细胞的比例。结果：缺血15 min 时,I/R 组和 七氟烷组平均动脉压和RPP 均显著下降;再灌注4 h 时,七氟烷组平均动脉压和RPP 均有所上升,相对于I/R 组, 差异具有统计学意义;与对照组比较,I/R 组内皮细胞ICAM-1、VCAM-1 和E- 选择素的表达均显著升高,七氟 烷则能够有效抑制I/R 引起的内皮细胞促炎分子的表达;对照组CD68+ 巨噬细胞为5.83 个/ 高倍镜视野（ HPF）, I/R 组数目为55.67 个/HPF,两组间差异具有统计学意义;七氟烷能够显著减少心组织内巨噬细胞的浸润,与I/R 组比较,降低了66.46%;TUNEL 染色结果显示对照组心肌细胞凋亡率2.20%,I/R 组为28.63%,两组间差异明显; 七氟烷能够显著降低心肌细胞的凋亡,相对于I/R 组,降低了51.76%。结论：七氟烷可降低缺血再灌注损伤后内 皮细胞表面促炎分子的表达,减少心肌组织巨噬细胞浸润和细胞凋亡。