扩张型心肌病心脏移植受者心脏病理学观察及微血管内皮细胞的表达及分布

目的:观察扩张型心肌病(DCM)心脏移植受者心脏病理学特点及微血管内皮细胞的表达及分布,初步探讨内皮细胞与心肌纤维化的作用。方法:以2012年1月至2017年6月期间,本院收治的10例因DCM终末期行心脏移植患者的受者心脏作为研究对象。对照组采用来自法医鉴定中心的非疾病死亡的正常成年人尸检心脏标本6例。采用HE染色、Masson三色组织化学染色观察DCM病理学改变,采用免疫组织化学方法检测CD34和α-SMA,观察微血管内皮细胞在DCM患者心肌组织中的表达。结果:(1)光镜下,终末期DCM的主要病理改变是心肌细胞退行性变,心肌间质纤维化;(2)通过透射电镜观察发现终,末期DCM主要改变是心肌退行性变,心肌肌原纤维Z线排列不规则,部分心肌细胞核肥大,心肌肌原纤维灶性溶解,心肌间质水肿,线粒体增多,线粒体肿胀空泡化,可见髓鞘样结构,心肌间质毛细血管内皮细胞胞质肿胀,细胞连接消失,吞饮小泡减少;(3)两组心肌组织中均有微血管内皮细胞分布,DCM中CD34表达明显低于对照组,α-SMA的表达明显高于对照组。结论:DCM中血管内皮细胞的超微结构变化,可能导致其功能改变,内皮细胞可能通过内皮间质细胞转化参与了DCM中心肌纤维化。     

利拉鲁肽改善糖尿病心肌病大鼠心脏脂质异位沉积的效果和机制研究

目的:观察利拉鲁肽对糖尿病心肌病(DCM)大鼠心脏脂质异位沉积的改善效果,并探讨相关作用机制。方法:8周龄雄性Wistar大鼠60只,随机抽取8只作为对照组,其余DCM造模。DCM造模成功大鼠24只,随机分为DCM组、低剂量利拉鲁肽治疗组(LL组)及高剂量利拉鲁肽治疗组(HL组),每组各8只。LL组[0.2 mg/(kg·d)]和HL组[0.4 mg/(kg·d)]给予利拉鲁肽皮下注射,每日1次,干预8周后,行超声心动图检测心功能后麻醉处死大鼠。心脏采血检测大鼠血糖、血脂、胰岛素水平。采用苏木素伊红染色和透射电镜观察心脏形态学变化和超微结构改变;比色法测定心肌游离脂肪酸(FFA)和二酰甘油(DAG)含量;实时PCR检测腺苷单磷酸活化蛋白激酶(AMPK)、叉头框转录因子1(FOXO1)、白细胞分化抗原36(CD36)、过氧化物酶增殖物激活受体α(PPARα)和B型利钠肽(BNP)基因表达情况;蛋白免疫印迹法检测AMPK、磷酸化AMPK(p-AMPK)、FOXO1和CD36蛋白表达情况。结果:与对照组相比,DCM组大鼠空腹血糖、空腹胰岛素、胰岛素抵抗指数、甘油三酯和低密度脂蛋白胆固醇水平显著升高,胰岛β细胞功能指数显著降低;左心室射血分数、左心室短轴缩短分数和每搏输出量均显著降低,左心室舒张早期最大血流/二尖瓣心房收缩期最大血流比值(E/A)明显升高,等容舒张时间显著延长且心脏重量指数增加;心肌细胞线粒体旁和肌丝间存在大量脂滴,心肌组织中FFA和DAG水平显著升高(P均0.05)。与DCM组相比,LL组和HL组大鼠脂质异位沉积减少,心肌中AMPK mRNA和p-AMPK/AMPK蛋白表达均增加,FOXO1、CD36的mRNA和蛋白表达水平均降低,PPARα和BNP的mRNA表达水平也降低(P均0.05)。结论:利拉鲁肽通过激活AMPK-FOXO1-CD36信号通路,改善糖尿病心肌病大鼠心肌脂质异位沉积,从而改善左心室收缩和舒张功能,发挥心脏保护作用。     

CD5+B细胞与扩张型心肌病相关性研究

目的:通过对扩张型心肌病(DCM)患者体内CD5 B细胞及其功能的检测,探讨它在DCM发生发展中的作用。方法:选择DCM患者42例,20例健康者为对照。采用双色流式细胞术检测患者外周血淋巴细胞中CD5 B细胞(CD19 CD5 )数,ELISA法检测血清抗心肌自身抗体(AHA)以及体外CD5 B细胞分泌IL-10功能;根据彩色多普勒检测心脏射血分数(EF)。结果:与对照组[(5.39±1.46)%]相比,DCM患者CD5 B细胞均有明显增多,其中AHA阳性者为(13.49±3.15)%,AHA阴性者(14.06±5.23)%,AHA阳性和阴性者CD5 B细胞差异无统计学意义。对照组AHA检测均为阴性。DCM患者CD5 B细胞的增多与心脏EF值无相关性(r=-0.25,P>0.05),但其分泌IL-10功能与EF值负相关(r=-0.64,P<0.01)。结论:CD5 B细胞不仅参与AHA阳性也参与AHA阴性DCM发病过程;有活性的CD5 B细胞介导DCM心力衰竭的进程。     

自噬在糖尿病心肌病发病机制中的作用研究进展

糖尿病心肌病(diabetic cardiomyopathy,DCM)是糖尿病患者发生心力衰竭和死亡的重要原因.过度自噬导致心肌受损,可能是DCM的发生发展机制之一.本文对自噬在DCM发生发展机制中的作用进行综述.NF-E2相关因子2(Nrf2)除对抗氧化损伤,还可通过负性调控AMPK抑制过度自噬.增加Nrf2活性可抑制AMPK-ULK1-Beclin1通路,降低自噬活性,减轻DCM所致心肌损伤,有望为DCM的防治提供新方向.     

通络玉液汤对2型糖尿病心肌病大鼠心肌形态结构和氧化指标的影响

目的探讨通络玉液汤对糖尿病心肌病(DCM)大鼠心肌形态结构和氧化指标的影响。方法采用高糖高脂饮食+小剂量链脲佐菌素腹腔注射的方法复制DCM模型。将36只大鼠随机分为3组:正常对照组、DCM组、通络玉液汤组。分别处理8 w后,测定大鼠空腹血糖(FBG)、血清丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性,左室重量指数(LVMI)和心脏重量指数(HWI),光镜及透射电镜观察心肌细胞形态结构。结果与正常对照组比较,DCM组FBG、MDA水平明显升高,SOD活性明显下降,LVMI和HWI明显增大(均P<0.01),心肌细胞肌原纤维排列紊乱、断裂、溶解,线粒体肿胀变性,嵴、膜断裂、缺失。与DCM组比较,通络玉液汤组FBG、MDA水平明显下降,SOD活性明显上升,LVMI和HWI明显下降(均P<0.01),病理改变明显减轻。结论通络玉液汤可降低血糖,对抗脂质过氧化反应、改善DCM心肌损伤。     

扩张型心肌病基因突变及基因治疗

扩张型心肌病（DCM）是一种常见的疾病，发病率为36．5／10万人，由于存在一些无症状患者，所以实际的发病率可能更高。DCM以心室扩张及心肌收缩功能减退为主要特征，可导致心力衰竭，严重心律失常和栓塞性疾病，这些也是导致DCM患者早期死亡的主要决定因素。近十余年来，随着分子遗传学的进展，在DCM的病因、发病机理等方面进行了深入研究，发现了一些与该类疾病有关的基因突变，家系研究提示约25％～30％的“原发型”DCM是由心肌骨架蛋白基因突变引起的。     

扩张型心肌病患者外周血CD4＋CD25＋T细胞变化及临床意义

目的探讨扩张型心肌病（DCM）患者外周血CD4＋CD2＋5T细胞变化及临床意义。方法采用流式细胞分析法检测30例DCM患者（DCM组）及20例健康者（对照组）的外周血CD4＋CD2＋5T细胞。结果外周血CD4＋CD2＋5T细胞占CD4＋T细胞的比例DCM组为（8.53±1.64）%,对照组为（11.4±2.17）%,两组比较有统计学差异（P〈0.01）;且DCM患者心功能越差,CD4＋CD2＋5T细胞占CD4＋T细胞的比例越低。结论DCM患者CD4＋CD2＋5T细胞比例减少,可能打破自身免疫耐受,发生针对心肌抗原的免疫反应,参与DCM发病。     

热休克蛋白60在扩张型心肌病中的意义

目的探讨心肌组织中热休克蛋白60(HSP60)在扩张型心肌病(DCM)发生、发展中的作用。方法应用免疫组化方法检测15例DCM患者及10例对照者心肌组织中HSP60的表达和分布。结果DCM患者心肌组织中HSP60的表达较对照组明显增加(P<0.05),而且发现HSP60阳性细胞主要局限于心肌纤维的连接区域。结论DCM患者心肌组织中HSP60的过高表达,可能与DCM的发生发展有关。     

CD36在动脉粥样硬化中的研究进展

CD36是巨噬细胞表面的一种清道夫受体,是巨噬细胞吸收氧化低密度脂蛋白(OX-LDL)的主要受体.OX-LDL是导致动脉粥样硬化(AS)发生的重要物质.AS斑块中,80%的成分来源于摄取脂质的巨噬细胞和由其转化形成的泡沫细胞.巨噬细胞通过CD36摄取大量的OX-LDL形成泡沫细胞.抑制CD36的表达可能与抗AS有关.本文就CD36的生物学特性、CD36在AS中作用和CD36的表达调节作一综述.     

嗜铬粒蛋白A在扩张型心肌病中的表达

目的观察扩张型心肌病（DCM）患者外周血及心肌组织中嗜铬粒蛋白A（CGA）的表达,初步探讨CGA在DCM发生发展中的作用。方法收集DCM患者及正常健康志愿者外周血血清,用ELISA方法检测样本血清中CGA水平。取DCM心脏移植患者的心肌组织样本,以及排除心脏疾病的脑外伤尸检心肌组织标本。利用RT—PCR技术检测心肌中CGA的mRNA在DCM心肌和正常心肌中的表达变化;应用免疫组化鉴定心肌中CGA的分布位置及其表达强弱变化。结果ELISA显示DCM患者外周血中CGA浓度为187．6±94．7ng／ml;正常健康志愿者外周血中CGA为130．6±21．1ng／ml（P〈0．05）。和正常对照心肌相比,RT—PCR证实DCM心肌组织中CGA—mRNA表达升高（P〈0．001）。免疫组化表明在DCM心肌中CGA颗粒粗大、部位密集,与正常心肌样本比较有统计学意义（P〈0．05）。结论作为神经内分泌活性强有力指标的CGA在DCM心肌及血循环中表达均升高,提示CGA可能参与了DCM的发病。     

Improvement in cardiac function and free fatty acid metabolism in a case of dilated cardiomyopathy with CD36 deficiency

A 27-year-old man diagnosed as having dilated cardiomyopathy (DCM) without myocardial accumulation of 123I-beta-methyl-iodophenylpentadecanoic acid, and he was found to have type I CD36 deficiency. This abnormality of cardiac free fatty acid metabolism was also confirmed by other methods: 18F-fluoro-2-deoxyglucose positron emission tomography, measurements of myocardial respiratory quotient and cardiac fatty acid uptake. Although the type I CD36 deficiency was reconfirmed after 3 months, the abnormal free fatty acid metabolism improved after carvedilol therapy and was accompanied by improved cardiac function. Apart from a cause-and-effect relationship, carvedilol can improve cardiac function and increase free fatty acid metabolism in patients with both DCM and CD36 deficiency.     

糖尿病心肌病发病机制的研究进展

糖尿病的发病率和患病率在全世界范围不断上升。糖尿病心肌病（DCM）是糖尿病主要的心脏并发症之一,其特征为左室舒张和（或）收缩功能障碍,也可伴有心力衰竭、心律失常、心源性休克,重症患者甚至猝死。DCM的发病机制尚未完全明确,目前认为其与心肌细胞的糖代谢、脂代谢与能量代谢异常,以及心肌纤维化、氧化应激和细胞死亡等多种因素有关。本文将从细胞、组织、分子水平等方面对DCM的发病机制的研究现状做一综述,以为临床防治提供依据。     

A growth hormone-releasing peptide promotes mitochondrial biogenesis and a fat burning-like phenotype through scavenger receptor CD36 in white adipocytes

Whereas the uptake of oxidized lipoproteins by scavenger receptor CD36 in macrophages has been associated with foam cell formation and atherogenesis, little is known about the role of CD36 in regulating lipid metabolism in adipocytes. Here we report that treatment of 3T3-L1 adipocytes with hexarelin, a GH-releasing peptide that interacts with CD36, resulted in a depletion of intracellular lipid content with no significant change in CD36 expression. Microarray analysis revealed an increased pattern in several genes involved in fatty acid mobilization toward the mitochondrial oxidative phosphorylation process in response to hexarelin. Interestingly, many of these up-regulated genes are known targets of peroxisomal proliferator-activated receptor (PPAR)-gamma, such as FATP, CPT-1, and F(1)-ATPase, suggesting that adipocyte response to hexarelin may involve PPARgamma activation. Expression studies also indicate an increase in thermogenic markers PPARgamma coactivator 1alpha and uncoupling protein-1, which are normally expressed in brown adipocytes. Electron microscopy of hexarelin-treated 3T3-L1 adipocytes showed an intense and highly organized cristae formation that spans the entire width of mitochondria, compared with untreated cells, and cytochrome c oxidase activity was enhanced by hexarelin, two features characteristic of highly oxidative tissues. A similar mitochondrial phenotype was detected in epididymal white fat of mice treated with hexarelin, along with an increased expression of thermogenic markers that was lost in treated CD36-null mice, suggesting that the ability of hexarelin to promote a brown fat-like phenotype also occurs in vivo and is dependent on CD36. These results provide a potential role for CD36 to impact the overall metabolic activity of fat usage and mitochondrial biogenesis in adipocytes.     

CD36 deficiency rescues lipotoxic cardiomyopathy

Obesity-related diabetes mellitus leads to increased myocardial uptake of fatty acids (FAs), resulting in a form of cardiac dysfunction referred to as lipotoxic cardiomyopathy. We have shown previously that chronic activation of the FA-activated nuclear receptor, peroxisome proliferator-activated receptor alpha (PPARalpha), is sufficient to drive the metabolic and functional abnormalities of the diabetic heart. Mice with cardiac-restricted overexpression of PPARalpha (myosin heavy chain [MHC]-PPARalpha) exhibit myocyte lipid accumulation and cardiac dysfunction. We sought to define the role of the long-chain FA transporter CD36 in the pathophysiology of lipotoxic forms of cardiomyopathy. MHC-PPARalpha mice were crossed with CD36-deficient mice (MHC-PPARalpha/CD36-/- mice). The absence of CD36 prevented myocyte triacylglyceride accumulation and cardiac dysfunction in the MHC-PPARalpha mice under basal conditions and following administration of high-fat diet. Surprisingly, the rescue of the MHC-PPARalpha phenotype by CD36 deficiency was associated with increased glucose uptake and oxidation rather than changes in FA utilization. As predicted by the metabolic changes, the activation of PPARalpha target genes involved in myocardial FA-oxidation pathways in the hearts of the MHC-PPARalpha mice was unchanged in the CD36-deficient background. However, PPARalpha-mediated suppression of genes involved in glucose uptake and oxidation was reversed in the MHC-PPARalpha/ CD36-/- mice. We conclude that CD36 is necessary for the development of lipotoxic cardiomyopathy in MHC-PPARalpha mice and that novel therapeutic strategies aimed at reducing CD36-mediated FA uptake show promise for the prevention or treatment of cardiac dysfunction related to obesity and diabetes.     

Distinct effects of short- and long-term leptin treatment on glucose and fatty acid uptake and metabolism in HL-1 cardiomyocytes

Alterations in cardiac glucose and fatty acid metabolism are possible contributors to the pathogenesis of heart failure in obesity. Here we examined the effect of leptin, the product of the obese (ob) gene, on metabolism in murine cardiomyocytes. Neither short-term (1 hour) nor long-term (24 hours) treatment with leptin (60 nmol/L) altered basal or insulin-stimulated glucose uptake and oxidation, glycogen synthesis, insulin receptor substrate 1 tyrosine, Akt, or glycogen synthase kinase 3beta phosphorylation. Extracellular lactate levels were also unaffected by leptin. However, leptin increased basal and insulin-stimulated palmitate uptake at both short and long exposure times and this corresponded with increased cell surface CD36 levels and elevated fatty acid transport protein 1 (FATP1) and CD36 protein content. Whereas short-term leptin treatment increased fatty acid oxidation, there was a decrease in oxidation after 24 hours. The former corresponded with increased acetyl coenzyme A carboxylase phosphorylation and the latter with increased expression of this enzyme. The discrepancy between uptake and oxidation of fatty acids led to a transient decrease in intracellular lipid content with lipid accumulation ensuing after 24 hours. In summary, we demonstrate that leptin did not alter glucose uptake or metabolism in murine cardiomyocytes. However, fatty acid uptake increased while oxidation decreased over time leading to intracellular lipid accumulation, which may lead to lipotoxic damage in heart failure.     

Prognostic Significance of Circulating Levels of Hepatocyte Growth Factor in Patients with Chagas' Disease and Idiopathic Dilated Cardiomyopathy

Objectives: Hepatocyte growth factor (HGF) plays an important role in the improvement in cardiac function and remodeling in a variety of cardiovascular diseases. It is also a strong predictor of mortality in some heart failure (HF) patients. However, its prognostic value in patients with Chagas' disease (CD) or idiopathic dilated cardiomyopathy (DCM) remains to be investigated. Methods and Results: In this prospective cohort study, HGF concentrations were measured in patients with CD (n = 91), DCM (n = 47), and control subjects (n = 25). While no difference was detected for patients with New York Heart Association class I-II, HGF was significantly increased in advanced HF patients (New York Heart Association class III-IV) in both CD and DCM groups, compared with healthy subjects. There was a strong correlation between HGF and left ventricular ejection fraction in CD patients. However, there was no correlation in patients with DCM. Despite its strong correlation with left ventricular ejection fraction in CD patients, HGF failed to predict mortality and necessity for heart transplant in both CD and DCM patients. Conclusions: Although HGF can be significantly increased in advanced HF patients with CD and DCM, its prognostic value for endpoints is minor. Therefore, the formerly described predictive power for HGF in HF might be restricted to specific etiologies of HF.     

Cardiac PPARalpha expression in patients with dilated cardiomyopathy

BACKGROUND: The peroxisome proliferator-activated receptor alpha (PPARalpha) is a central regulator of myocardial fatty acid (FA) metabolism implicated in the pathogenesis of heart failure. AIMS: To characterize PPARalpha regulation in human dilated cardiomyopathy (DCM), we studied the expression of cardiac PPARalpha, cardiac carnitine palmitoyl-transferase I (CPT-1), a major PPARalpha target gene, and of the cardiac glucose transporter GLUT-4 in patients with DCM. METHODS: Left ventricular biopsies were taken from patients with DCM (n=16) and control subjects (n=15), and mRNA expression was quantitated using real-time PCR (SYBR((R))Green) and protein expression was measured by Western immunoblotting. RESULTS: Left ventricular PPARalpha mRNA levels were significantly increased in the DCM group compared to the control group (136+/-25.4% vs. control, p<0.01). Consistently, DCM patients had a significantly higher cardiac CPT-1 mRNA expression (147+/-51% vs. control, p<0.05) compared to the control group. Cardiac GLUT-4 expression was similar in both groups. CONCLUSION: Elevated cardiac PPARalpha levels followed by an induction of cardiac CPT-1 expression may result in increased fatty acid metabolism for cardiac energy production in DCM, suggesting a specific cardiac metabolic program in human DCM compared to other types of cardiomyopathy.     

CD36 deficiency protects against malarial anaemia in children by reducing Plasmodium falciparum-infected red blood cell adherence to vascular endothelium

Objective  CD36 is a receptor that occurs on the surface of activated immune cells, vascular endothelial cells and participates in phagocytosis and lipid metabolism. CD36 is known to be the major endothelial receptor molecule for field isolates of Plasmodium falciparum. A T1264G mutation in exon X of the gene leads to deficiency of CD36. This study aimed at determining associations between CD36 deficiency, P. falciparum in vitro adherence on purified CD36 and anaemia among children in an endemic area.
Methods  Genotypes were determined by nested polymerase chain reaction of isolated DNA from filter blood spots followed by Restriction Fragment Length Polymorphism (RFLP). Plasmodium falciparum adherence assays were performed on immobilized purified CD36.
Results  The data indicate that CD36 is an important cytoadherence receptor that mediates adherence to most P. falciparum field isolates. Our findings also suggest that mutations causing CD36 deficiency may confer significant protection against malarial anaemia (MA) in children (χ² = 8.58, P  < 0.01).
Conclusion  That the protective role that CD36 deficiency may confer against MA in children seems to be mediated through reduced cytoadherence of infected red blood cells to vascular endothelium.     

Regulation of sarcolemmal glucose and fatty acid transporters in cardiac disease

Circulating long-chain fatty acids (LCFA) and glucose are the main sources for energy production in the heart. In the healthy heart the ratio of glucose and LCFA oxidation is sensitively balanced and chronic alterations in this substrate mix are closely associated with cardiac dysfunction. While it has been accepted for several years that cardiac glucose uptake is mediated by facilitated transport, i.e. by means of the glucose transport proteins GLUT1 and GLUT4, only in the last few years it has become clear that proteins with high-affinity binding sites to LCFA, referred to as LCFA transporters, are responsible for bulk LCFA uptake. Similar to the GLUTs, the LCFA transporters CD36 and FABP(pm) can be recruited from an intracellular storage compartment to the sarcolemma to increase the rate of substrate uptake. Permanent relocation of LCFA transporters, mainly CD36, from intracellular stores to the sarcolemma is accompanied by accumulation of lipids and lipid metabolites in the heart. As a consequence, insulin signalling and glucose utilization are impaired, leading to decreased contractile activity of the heart. These observations underline the particular role and interplay of substrate carriers for glucose and LCFA in modulating cardiac metabolism, and the development of heart failure. The signalling and trafficking pathways and subcellular machinery regulating translocation of glucose and LCFA transporters are beginning to be unravelled. More knowledge on substrate transporter recycling, especially the similarities and differences between glucose and LCFA transporters, is expected to enable novel therapies aimed at changing the subcellular distribution of glucose and LCFA transporters, thereby manipulating the substrate preference of the diseased heart to help restore cardiac function.