Drosophila melanogaster as a model to study drug addiction

Animal studies have been instrumental in providing knowledge about the molecular and neural mechanisms underlying drug addiction. Recently, the fruit fly Drosophila melanogaster has become a valuable system to model not only the acute stimulating and sedating effects of drugs but also their more complex rewarding properties. In this review, we describe the advantages of using the fly to study drug-related behavior, provide a brief overview of the behavioral assays used, and review the molecular mechanisms and neural circuits underlying drug-induced behavior in flies. Many of these mechanisms have been validated in mammals, suggesting that the fly is a useful model to understand the mechanisms underlying addiction.     

Review of T-wave morphology-based biomarkers of ventricular repolarisation using the surface electrocardiogram

Many drugs fail in clinical trials due to adverse effects on cardiac electrical function, as measured by an increase in the QT interval in the surface electrocardiogram (ECG). However, there are several limitations associated with the QT interval, including poor sensitivity and specificity in predicting drug-induced arrhythmia. This is a growing concern for both regulatory and pharmaceutical agencies, as it translates into significant socio-economic costs. As a result, there has been a growing interest in identifying alternative biomarkers of drug-induced arrhythmia. Studies of the electrophysiological mechanisms underlying drug-induced arrhythmia have identified the morphology of the T-wave as a potential indicator of proarrhythmic activity. A plethora of new T-wave morphology based biomarkers have been proposed recently. This article presents a comprehensive review of the recently published biomarkers of drug-induced arrhythmia based on T-wave morphology.     

Conundrum of pathogenesis of diabetic cardiomyopathy: role of vascular endothelial dysfunction, reactive oxygen species, and mitochondria

Diabetic cardiomyopathy and heart failure have been recognized as the leading causes of mortality among diabetics. Diabetic cardiomyopathy has been characterized primarily by the manifestation of left ventricular dysfunction that is independent of coronary artery disease and hypertension among the patients affected by diabetes mellitus. A complex array of contributing factors including the hypertrophy of left ventricle, alterations of metabolism, microvascular pathology, insulin resistance, fibrosis, apoptotic cell death, and oxidative stress have been implicated in the pathogenesis of diabetic cardiomyopathy. Nevertheless, the exact mechanisms underlying the pathogenesis of diabetic cardiomyopathy are yet to be established. The critical involvement of multifarious factors including the vascular endothelial dysfunction, microangiopathy, reactive oxygen species (ROS), oxidative stress, mitochondrial dysfunction has been identified in the mechanism of pathogenesis of diabetic cardiomyopathy. Although it is difficult to establish how each factor contributes to disease, the involvement of ROS and mitochondrial dysfunction are emerging as front-runners in the mechanism of pathogenesis of diabetic cardiomyopathy. This review highlights the role of vascular endothelial dysfunction, ROS, oxidative stress, and mitochondriopathy in the pathogenesis of diabetic cardiomyopathy. Furthermore, the review emphasizes that the puzzle has to be solved to firmly establish the mitochondrial and/or ROS mechanism(s) by identifying their most critical molecular players involved at both spatial and temporal levels in diabetic cardiomyopathy as targets for specific and effective pharmacological/therapeutic interventions.     

Characterization of anti-heart M2 muscarinic receptor antibodies — a combined clinical and experimental study

To elucidate the relationship between autoinimunity and idiopathic dilated cardiomyopathy has been one of today's heated topics in the field of heart research. So far it has been identified that there are a variety of autoantibodies including antireceptor autoantibodies. However, the role of these autoantibodies in the development of dilated cardiomyopathy has not been defined. An increasing number of in vitro studies showed that these autoantibodies had different functions, suggesting that they may play different roles in the pathogenesis of cardiomyopathy. The main purpose of this article is to briefly go through the results obtained from both clinical and experimental in vitro studies on anti-M2 muscarinic receptor antibodies to see where we stand in the understanding of the role of these autoantibodies in the pathogenesis of idiopathic dilated cardiomyopathy.     

Suppression of nitrative damage by metallothionein in diabetic heart contributes to the prevention of cardiomyopathy

Diabetic cardiomyopathy has become a major contributor to the increased mortality of diabetic patients. Although the development and progression of diabetic cardiomyopathy are considered to be associated with diabetes-derived oxidative stress, the precise mechanisms for and effectively preventive approaches to diabetic cardiomyopathy remain to be explored. Recent studies showed that reactive oxygen or nitrogen species (ROS/RNS) not only play a critical role in the initiation of diabetic cardiomyopathy, but also play an important role in physiological signaling. Therefore, this review will first discuss the dual roles of ROS/RNS in the physiological signaling and pathogenic remodeling leading to cardiomyopathy under diabetic conditions. The significant prevention of diabetic cardiomyopathy by metallothionein (MT) as a potent and nonspecific antioxidant will be also summarized. It is clearly revealed that although dual roles of peroxynitrite-nitrated proteins have been indicated under both physiological and pathogenic conditions, suppression of nitrative damage by MT in the diabetic heart is the major mechanism responsible for its prevention of diabetic cardiomyopathy. Finally the potential for clinical enhancement of the cardiac MT expression to prevent or delay the occurrence of cardiomyopathy in diabetic patients will also be addressed.     

Drug-induced skin reactions and acute cutaneous graft-versus-host reaction: a comparative immunohistochemical study

Skin biopsies from eight patients with drug-induced dermatitis have been compared with skin biopsies from 16 patients developing skin lesions (acute graft versus host-reaction and/or drug-induced reaction) after bone marrow transplantation. Biopsies were investigated using immunohistochemistry and several monoclonal antibodies. Morphological and immunohistochemical patterns in skin biopsies of both groups were very similar. The only difference seen was a reduced number of epidermal Langerhans cells with poorly developed dendrites in skin biopsies taken from patients who underwent bone marrow transplantation. If the latter finding is due to the cytotoxic drug regimen administered before bone marrow transplantation, as previously stated, we doubt the usefulness of skin biopsies in the differential diagnosis of acute graft-versus-host reaction and drug-induced skin lesions.     

Cardiomyopathies: a revolution in molecular medicine and cardiac imaging

The cardiomyopathies are defined as: ‘a myocardial disorder in which the heart is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension and congenital heart disease sufficient to cause the myocardial abnormality.’1 With the advent of molecular cardiology and cardiovascular imaging (including MRI and echocardiography) in the last decade, much insight has been gained into the different clinical presentations, its familial and genetic causes and pathophysiology in explaining left ventricular function and prognosis. This has been especially true for hypertrophic cardiomyopathy, but also for dilated cardiomyopathy (DCM) and RV cardiomyopathy.     

Implications of protease activation in cardiac dysfunction and development of genetic cardiomyopathy in hamsters

It has become evident that protein degradation by proteolytic enzymes, known as proteases, is partly responsible for cardiovascular dysfunction in various types of heart disease. Both extracellular and intracellular alterations in proteolytic activities are invariably seen in heart failure associated with hypertrophic cardiomyopathy, dilated cardiomyopathy, hypertensive cardiomyopathy, diabetic cardiomyopathy, and ischemic cardiomyopathy. Genetic cardiomyopathy displayed in different strains of hamsters provides a useful model for studying heart failure due to either cardiac hypertrophy or cardiac dilation. Alterations in the function of several myocardial organelles such as sarcolemma, sarcoplasmic reticulum, myofibrils, mitochondria, as well as extracellular matrix have been shown to be due to subcellular remodeling as a consequence of changes in gene expression and protein content in failing hearts from cardiomyopathic hamsters. In view of the increased activities of various proteases, including calpains and matrix metalloproteinases in the hearts of genetically determined hamsters, it is proposed that the activation of different proteases may also represent an important determinant of subcellular remodeling and cardiac dysfunction associated with genetic cardiomyopathy.     

Drug-induced Blood Dyscrasias in Sweden

Cases of drug-induced aplastic anaemia, haemolytic anaemia, thrombocytopenia, and agranulocytosis reported to the Swedish Adverse Drug Reaction Committee during the five-year period 1966-70 have been analysed and compared with cases of the same cytopenias from “all” causes. Oral diuretics were a dominant cause of drug-induced thrombocytopenia, methyldopa of haemolytic anaemia, and oxyphenbutazone of aplastic anaemia. Computer systems should help such studies, particularly in showing a changing pattern of complications and causes.     

Plasma carnitine concentrations in cardiomyopathy patients

Carnitine is an essential cofactor for the beta-oxidation of fats. Both hypertrophic and congestive cardiomyopathies have been reported in primary and secondary carnitine deficiency. Conversely in avian cardiomyopathy models abnormally elevated plasma and tissue carnitine concentrations have been described. We measured plasma carnitine concentrations in 25 cardiomyopathy patients. In 14 patients with either hypertrophic or congestive cardiomyopathy plasma carnitine concentrations were abnormally elevated. Patients with secondary cardiomyopathies tended to have normal carnitine values. One patient with systemic carnitine deficiency was diagnosed. Her cardiac function normalized with L-carnitine replacement. Six of 14 patients with high plasma carnitine concentrations died. None of the 10 with low or normal plasma carnitine have died. Plasma carnitine determination may be a useful adjunct in the diagnostic evaluation of idiopathic cardiomyopathy.     

HIV protease inhibitors-induced atherosclerosis: prevention by alpha-tocopherol

Prolonged treatments with inhibitors of human immunodeficiency(HIV)-encoded protease (ARPI) have been reported to induce early atherosclerotic events. Our in vitro study indicates that alpha-tocopherol may prevent drug-induced premature atherosclerosis since it interferes with CD36 scavenger receptor over-expression induced by ritonavir in monocytes. The mechanism of CD36 upregulation by ritonavir involves inhibition of the ubiquitin-proteasome system and alpha-tocopherol is able to normalize proteasome activity. These findings suggest that ARPI combined with early alpha-tocopherol supplementation may decrease the drug-induced atherosclerotic risk.     

Basal wall hypercontraction of Takotsubo cardiomyopathy in a patient who had been diagnosed with dilated cardiomyopathy: a case report

Background

Takotsubo cardiomyopathy is characterized by the basal hypercontractility and apical ballooning of the left ventriculum and T-wave inversion in the electrocardiogram. It has been suggested that Takotsubo cardiomyopathy might underlie the pathogenesis of persistent cardiac dysfunction; however, few reports are present demonstrating the advent of Takotsubo cardiomyopathy in patients with idiopathic cardiomyopathy.

Case presentation

A 64-year-old women was admitted due to dyspnea on effort and lower extremity edema. She had been diagnosed with idiopathic dilated cardiomyopathy 2.5 years before owing to the reduced left ventricular ejection fraction (24%), normal coronary artery, and interstitial fibrosis of the myocardial samples. On admission, her electrocardiogram showed giant negative T wave in II, III, aVF, and precordial leads. Echocardiography showed dyskinesis of the left ventricular apex and hypercontraction of the basal wall, which had not been observed in the previous examinations. Coronary angiography showed normal coronary arteries, and apical ballooning and basal hypercontractility was confirmed by left ventriculography. On day 15 of admission, contraction of apical wall was recovered, and basal hypercontraction was disappeared.

Conclusion

The present case is the first report demonstrating appearance the transient basal wall hypercontraction along with the advent of Takotsubo cardiomyopathy in a patient diagnosed with dilated cardiomyopathy. Whether such findings are indicative of fair prognosis and have the utility of understanding the pathogenesis of dilated cardiomyopathy needs further investigation.

     

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

The onset of sudden cardiac death and large inter- and intra-familial clinical variability of hypertrophic cardiomyopathy pose an important clinical challenge. Cardiac magnetic resonance imaging is a high-resolution imaging modality that has become increasingly available in the past decade and has the unique possibility to demonstrate the presence of fibrosis or scar using late gadolinium enhancement imaging. As a result, the diagnostic and prognostic potential of cardiac magnetic resonance imaging has been extensively explored in acute and chronic ischaemic cardiomyopathy, as well as in several nonischaemic cardiomyopathies. This review aims to provide a critical overview of recently published studies on hypertrophic cardiomyopathy and discusses the role of cardiac magnetic resonance imaging in differentiating underlying causes of hypertrophic cardiomyopathy, such as familial hypertrophic cardiomyopathy, cardiac involvement in systemic disease and left ventricular hypertrophy due to endurance sports. Also, it demonstrates the use of cardiac magnetic resonance in risk stratification for the onset of sudden cardiac death, and early identification of asymptomatic family members of hypertrophic cardiomyopathy patients who are at risk for the development of hypertrophic cardiomyopathy. (Neth Heart J 2010;18:135-43.)     

Non‐coding RNA involvement in the pathogenesis of diabetic cardiomyopathy

In recent years, the incidence of diabetes has been increasing rapidly, which seriously endangers human health. Diabetic cardiomyopathy, an important cardiovascular complication of diabetes, is characterized by myocardial fibrosis, ventricular remodelling and cardiac dysfunction. It has been documented that mitochondrial dysfunction, oxidative stress, inflammatory response, autophagy, apoptosis, diabetic microangiopathy and myocardial fibrosis are implicated in the pathogenesis of diabetic cardiomyopathy. With the development of molecular biology technology, accumulating evidence demonstrates that non‐coding RNAs (ncRNAs) are critically involved in the molecular mechanisms of diabetic cardiomyopathy. In this review, we summarize the pathological roles of three types of ncRNAs (microRNA, long ncRNA and circular RNA) in the progression of diabetic cardiomyopathy, which may provide valuable insights into the pathogenesis of diabetic cardiovascular complications.     

Catecholamine-Induced Cardiomyopathy

ObjectiveTo review the pathogenesis as well as the clinical and laboratory features of catecholamine-induced cardiomyopathy associated with pheochromocytoma and other disorders and discuss the various treatment options available.MethodsMaterials used for this article were identified through MEDLINE, PubMed, and Google Scholar searches of the relevant literature from 1955 to the present.ResultsCatecholamines and their oxidation products cause a direct toxic effect on the myocardium. Catecholamines also exert a receptor-mediated effect on the myocardium. Catecholamine-mediated myocardial stunning has been implicated in the pathogenesis of stressinduced cardiomyopathy. Biopsy of the myocardium in patients with pheochromocytoma or those with stressinduced cardiomyopathy shows similar pathologic findings. The clinical features in pheochromocytoma-related cardiomyopathy include hypertension, dilated or hypertrophic cardiomyopathy, pulmonary edema due to cardiogenic and noncardiogenic factors, cardiac arrhythmias, and even cardiac arrest. Stress-related cardiomyopathy such as takotsubo cardiomyopathy occurs primarily in postmenopausal women. These patients may present with clinical features suggestive of an acute myocardial infarction or a hemodynamically compromised state. The definitive management of cardiomyopathy associated with pheochromocytoma includes medical treatment with α-adrenergic blockade, possibly along with angiotensinconverting enzyme blockers and β₁-adrenergic receptor blockers, followed by excision of the tumor. Stressinduced cardiomyopathy is usually self-limiting; patients may require support with nonadrenergic inotropes.ConclusionRecognition of catecholamine-induced cardiomyopathy, especially in patients with pheochromocytoma, before surgical treatment is important to minimize morbidity and mortality. (Endocr Pract. 2008;14:1137- 1149)     

心肌肌钙蛋白T基因突变在心肌病发病机制中的研究进展

肥厚型和扩张型心肌病中,基因缺陷分别占发病的50％和35％,其病理生理机制,主要包括肌小节蛋白基因突变引起的收缩力产生缺陷,细胞骨架蛋白基因突变引起的收缩力传递缺陷等。心肌肌钙蛋白T将肌钙蛋白C和肌钙蛋白I连接到肌动蛋白和原肌球蛋白上,在心肌细胞收缩和舒张过程中发挥重要作用。在肥厚型和扩张型心肌病中发现了多种心肌肌钙蛋白T的基因突变,围绕心肌肌钙蛋白T的研究有助于阐明心肌病的发病机制。本文总结了心肌肌钙蛋白T基因突变在心肌病发病机制中的研究情况。     

Quantitative proteomics study of protective effects of grape seed procyanidin B2 on diabetic cardiomyopathy in db/db mice

Diabetic cardiomyopathy is one of the major complications of diabetes mellitus. Oxidative stress appears to play a substantial role in cardiomyopathy. Grape seed procyanidin B2 (GSPB2) has been known as an anti-oxidant in treating diabetes mellitus; however, little is known about its effects and underlying mechanisms on diabetic cardiomyopathy. The present study is to explore the molecular targets of GSPB2 responsible for the anti-oxidative effects in db/db mice by quantitative proteomics. GSPB2 (30?mg/kg body weight/day) were intragastric administrated to db/db mice for 10?weeks. Proteomics of the heart tissue extracts by isobaric tags for relative and absolute quantification analysis was obtained from db/db mice. Our study provides important evidence that GSPB2 protect against cardiomyopathy in diabetes mellitus, which are believed to result from regulating the expression of key proteins involving cardiac fibrosis and proliferation. GSPB2 could be expected to become novel clinical application in fighting against diabetic cardiomyopathy.     

Nonischemic Cardiomyopathy Associated with Autoimmune Polyglandular Syndrome Type II

ObjectiveTo report a case of nonischemic cardiomyopathy associated with autoimmune polyglandular syndrome type II (APS-II).MethodsWe describe our patient’s clinical features, evaluation, and outcome. In addition, a literature review of cardiomyopathy associated with polyendocrinopathy syndromes is presented.ResultsThe component disorders of APS-II are Addison’s disease in combination with either autoimmune thyroid disease or type 1 (insulin-dependent) diabetes. Although numerous other autoimmune conditions have been reported in conjunction with APS-II, cardiomyopathy has not been previously described as part of this syndrome. The current patient was a 32-year-old man who, during a 5-year period, was diagnosed as having type 1 diabetes mellitus, Crohn’s disease, and Addison’s disease. In 2001, he presented with severe heart failure that progressed rapidly and eventually necessitated cardiac transplantation.ConclusionAlthough autoimmune cardiomyopathy has been associated with other autoimmune disorders, to our knowledge this is the first reported case of cardiomyopathy in association with an autoimmune polyglandular syndrome. Patients with this syndrome should undergo clinical evaluation for heart failure. (Endocr Pract. 2007;13:59-62)     

神经递质转运蛋白在应激性心肌病发病中的潜在作用

应激性心肌病是强烈应激诱发的心血管急症,自20世纪90年代初Dote首次报告后,世界各地临床报告病例逐年攀升。发病机制迄今尚不完全清楚,但交感神经过度激活,大量释放去甲肾上腺素在本病发生中起重要作用。根据相关研究进展,主要综述神经递质转运蛋白调控神经递质及交感神经活性在这一神经源性心脏病中可能发挥的重要作用。