Hirofumi Deguchi

Evaluation of viral infection in the myocardium of patients with idiopathic dilated cardiomyopathy

OBJECTIVES The aim of this study was to evaluate the viral etiology of idiopathic dilated cardiomyopathy (DCM). BACKGROUND The demonstration of enteroviral genome in hearts with DCM has reinforced the importance of enteroviruses in the pathogenesis of DCM. However, there is uncertainty about the character and activity of enteroviruses detected in the myocardium. Recently, the association of hepatitis C virus or adenovirus with DCM has been reported. METHODS Myocardial specimens from 26 patients with idiopathic DCM, which were obtained at partial left ventriculectomy (PLV), were examined virologically. Strand-specific detection of enteroviral RNA was performed to differentiate active viral replication from latent persistence. Polymerase chain reaction was used to detect genomic sequences of hepatitis C virus, adenovirus, cytomegalovirus, influenza viruses, mumps virus, herpes simplex viruses, varicella-zoster virus and Epstein-Barr virus. RESULTS Plus-strand enteroviral RNA was detected in 9 (35%) of the 26 patients. Minus-strand enteroviral RNA was determined in seven (78%) of these nine plus-strand RNA-positive patients. Sequence analysis revealed that the enteroviruses detected were coxsackie B viruses, such as coxsackievirus B3 and B4. However, genetic material from other viruses was not detected. Six (86%) of seven minus-strand enteroviral RNA-positive patients died of cardiac insufficiency within the first six months after PLV. CONCLUSIONS Coxsackie B viruses were seen in hearts with idiopathic DCM. Active viral RNA replication appeared to be present in a significant proportion of these cases. Minus-strand coxsackieviral RNA in the myocardium can be a marker for poor clinical outcome after PLV. There was no evidence of persistent infection by other viruses in hearts with DCM.

Point mutations in mitochondrial DNA in patients with hypertrophic cardiomyopathy

Recent advances suggest that mutations in nuclear DNA are involved in the etiology of autosomal dominant hypertrophic cardiomyopathy. Mitochondria have their own DNA, and mutations in mitochondrial DNA have been shown to contribute to the genesis of various diseases. In this study, we developed rapid sequencing methods with the use of a fluorescence-based sequencing system and analyzed total mitochondrial DNA of seven patients with nonautosomal dominant hypertrophic cardiomyopathy. Multiple point mutations were observed in all patients with hypertrophic cardiomyopathy, although some of them were common among the subjects examined and the others are unique to each subject. Point mutations in transfer RNA genes were observed in five of the seven patients, and point mutations that replaced conserved amino acids were also observed. These mutations may result in the impairment of mitochondrial function. According to these results, mutations in mitochondrial DNA may contribute to the genesis of some cases of nonautosomal dominant hypertrophic cardiomyopathy, and our methods may be useful for the detection of point mutations in mitochondrial DNA.

Patients with idiopathic cardiomyopathy belong to the same mitochondrial DNA gene family of Parkinson's disease and mitochondrial encephalomyopathy

Comparison of total mitochondrial DNA sequences of patients with idiopathic (deleted or hypertrophic) cardiomyopathy with those of patients with Parkinsons disease and mitochondrial encephalomyopathies revealed distinct clustering of point mutations among patients. Furthermore, an inverse relation was found between the total number of base-substitution and life span of the patients. Among point mutations found in each patient, sequentially diverged six clusters consisting of 14, 10, 7, 1, 2, and 3 mutations, respectively, were detected. Five sub-clusters consisting of 2, 2, 11, 1, and 1 mutations, respectively, were detected. From each cluster, the patients unique mutations were diverged with three types of the mutations specific for the disease. The divergence allowed construction of a phylogenetic tree which clearly indicated that patients with idiopathic cardiomyopathy belong to the same mitochondrial DNA gene family of Parkinsons disease and mitochondrial encephalomyopathies.

Molecular detection and differentiation of enteroviruses in endomyocardial biopsies and pericardial effusions from dilated cardiomyopathy and myocarditis.

Enteroviruses (EVs), especially group B coxsackieviruses, have been implicated in the pathogenesis of myocarditis and dilated cardiomyopathy (DCM). To determine whether a specific type of EV is present in DCM hearts, we examined the genotypes of EVs detected in endomyocardial biopsies and pericardial effusions by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. Positive PCR results were obtained from biopsies in 6 (19 percent) of 31 patients with DCM, 5 (18 percent) of 28 with myocarditis, 5 (22 percent) of 23 with other cardiac diseases, and from pericardial effusions in 4 (57 percent) of 7 patients with pericarditis. SSCP profiles of most of the clinical samples were different and were not identical to any of the standard group B coxsackie viruses. Our findings suggest that EV genomes are involved in the myocardium of patients with various cardiac conditions and that a particular type of EV is not present in DCM hearts.

Evolution to dilated cardiomyopathy from acute eosinophilic pancarditis in Churg-Strauss syndrome

SummaryWe describe the clinical manifestations of a patient with Churg-Strauss syndrome who presented with severe acute cardiac involvement and whose disease evolved to dilated cardiomyopathy (DCM), with special reference to the histopathological findings. Endomyocardial biopsies, conducted sequentially, three times within 10 months, revealed severe eosinophilic endomyocarditis in the acute phase, interstitial fibrosis in the subacute phase, and endocardial thickening with mural thrombi, at 10 months. Although acute inflammation associated with elevation of eosinophil granule proteins subsided with steroid therapy, left ventricular dilatation with reduced contractility progressed. A subgroup of DCM is not considered to be idiopathic but, rather, an aftereffect of hypereosinophilic heart disease.

Viral and idiopathic myocarditis in Japan: a questionnaire survey.

SummaryIn order to study the current clinical status of viral and idiopathic myocarditis in Japan, we conducted a questionnaire survey and collected data for 218 cases from 62 institutions. The diagnosis was based on clinical and laboratory findings alone in 45% of the cases, and it included endomyocardial biopsy in 24% and autopsy in 9% of the patients. Endomyocardial biopsies were available in 40% of the patients; definite cellular infiltrations were identified in half the cases. Regardless of the biopsy findings or availability of biopsy, males predominated in the patient population; the mean age range was 30–39 years for both sexes. Cardiac symptoms and signs were common in addition to “common cold” symptoms; ECG abnormalities, leukocytosis, accelerated erythrocyte sedimentation rate, positive CRP, and increased cardiac enzyme levels were also very common in the acute phase of the disease. Serologic tests for virus titers, performed in 80% of the cases, were positive in 21%. There was no apparent correlation between serologic results and endomyocardial biopsy findings. In this survey, complete recovery occured in 43%, cure with sequelae in 40%, recurrences in 3%, and death in 13% of the total patient population.

Quantitative Analysis of Cytokine mRNA Expression in Hearts from Patients with Nonischemic Dilated Cardiomyopathy (DCM)

Abstract Purpose and Methods: There is increasing evidence that inflammatory cytokines play an important role in the development of heart failure. To evaluate the role of cytokines in nonischemic DCM, we analyzed the relative quantity of cytokine mRNA expression in the hearts from DCM patients with refractory heart failure, using the ABI PRISM7700 real‐time PCR system. We used heart tissues resected from 32 DCM patients at the time of elective partial ventriculectomy (PLV), and five biopsy specimens with normal histological findings as control.

Collagen subtypes and matrix metalloproteinase in idiopathic restrictive cardiomyopathy

BACKGROUND Idiopathic restrictive cardiomyopathy is a rare disease characterized by diastolic dysfunction, and the pathogenesis of the stiff heart remains unclear. The purpose of this study was to analyze the subpopulation of collagen fibers and determine the expression of matrix metalloproteinase in restrictive cardiomyopathy. METHODS AND RESULTS In endomyocardial biopsy specimens obtained from seven patients with restrictive cardiomyopathy, collagen fiber types I, III, and IV, and matrix metalloproteinase- and two were observed by light and electron microscopy, using monoclonal antibodies. Type I collagen was less prominent in the interstitium, whereas the immunoreactivity for type III collagen was marked. The immunoreactivity against matrix metalloproteinase-1 was observed along with types I and III collagen fibers and in the cytoplasm of some fibrocytes/fibroblasts. The matrix metalloproteinase-1 tended to increase when the reactivity against types I and III collagen was prominent. Both type IV collagen and matrix metalloproteinase-2 were observed along arterial walls and the basement membrane of cardiocytes. CONCLUSIONS Increased type III collagen may play an important role as the cause of left ventricular stiffness in restrictive cardiomyopathy. The matrix metalloproteinase appeared to be involved in a cascade of collagen synthesis and the remodeling of the heart in patients with restrictive cardiomyopathy.

Ultrastructural alterations of the conduction system in mice exhibiting sinus arrest or heart block during coxsackievirus B3 acute myocarditis

By light and electron microscopy we studied the sinus nodes and atrioventricular (AV) conducting tissue of six C3H/He mice having coxsackievirus B3 acute myocarditis. Sinus arrest was documented in all six mice, and second- or third-degree AV block was documented in three of the six mice. Although myocarditic changes in the conduction system, especially in the sinus node, were less than those in atrial and ventricular working myocardium, there were distinct abnormalities within both the sinus node and AV conducting tissue in all six hearts. Important ultrastructural alterations were inflammatory cell infiltrates and significant injury of specialized cells and of neural tissue. Specialized cells showed various features of degeneration and necrosis. Neural tissue damage included degeneration of axons and Schwann cells and disorganization of the neuromuscular junctions. Inflammatory cells, particularly macrophages, were often in intimate contact with injured specialized cells and neural tissue. Interstitial edema and bleeding and lymphatic vessel dilatation were also observed. These pathologic changes are considered to play an important role in the development of the documented disturbances of rhythm and conduction.

Electron-microscopic and immunohistochemical studies on endomyocardial biopsies from a patient with eosinophilic endomyocardial disease.

SummaryLight- and electron-microscopic studies and immunohistochemical procedures were carried out on blood eosinophils and left ventricular endomyocardial biopsies from a 68-year-old man with an eosinophilia of 8.2 × 109/l and congestive cardiac failure due to eosinophilic endomyocardial disease. Some blood eosinophils were vacuolated and degranulated, and reversal of the normal staining pattern of eosinophil granules was seen by means of electron microscopy. The biopsies showed degenerative changes in the cardiac myocytes, with interstitial fibrosis and infiltration by numerous eosinophils, mast cells, and macrophages. Eosinophils infiltrating the myocardium showed a decrease in the number of granules, many of which were indistinct or contained dissolving crystalloids, which occasionally were seen to be discharged onto the surface of adjacent cardiac myocytes. Immunohistochemical studies of the endomyocardial biopsies with a monoclonal antibody, which is specific for activated eosinophils and binds to the secreted forms of eosinophil cationic protein (ECP) and eosinophil protein-X (EP-X), demonstrated that the lesions contained numerous activated eosinophils and secreted ECP and EP-X. These findings support the concept that in eosinophilic endomyocardial disease, activated eosinophils infiltrate and degranulate in the myocardium, releasing eosinophil cationic proteins which then damage adjacent myocardial cells.