The frequency of familial dilated cardiomyopathy in a series of patients with idiopathic dilated cardiomyopathy.

BACKGROUND. Dilated cardiomyopathy is characterized by an increase in ventricular size and impairment of ventricular function. Most cases are believed to be sporadic, and familial dilated cardiomyopathy is usually considered to be a rare and distinct disorder. We studied the proportion of cases of idiopathic dilated cardiomyopathy that were familial in a large sequential series of patients whose first-degree relatives were investigated regardless of whether these relatives had cardiac symptoms. METHODS. We studied relatives of 59 index patients with idiopathic dilated cardiomyopathy of obtaining a family history and performing a physical examination, electrocardiography, and two-dimensional, M-mode, and Doppler echocardiography. A total of 315 relatives were examined. RESULTS. Eighteen relatives from 12 families were shown to have dilated cardiomyopathy. Thus, 12 of the 59 index patients (20.3 percent) had familial disease. There was no difference in age, sex, severity of disease, exposure to selected environmental factors, or electrocardiographic or echocardiographic features between the index patients with familial disease and those with nonfamilial disease. A noteworthy finding was that 22 of 240 healthy relatives (9.2 percent) with normal ejection fractions had increased left ventricular diameters during systole or diastole (or both), as compared with 2 of 112 healthy control subjects (1.8 percent) who were studied separately. CONCLUSIONS. Dilated cardiomyopathy was found to be familial in at least one in five of the patients in this study, a considerably higher percentage than in previous reports. This finding has important implications for family screening and provides direction for further investigation into the causes and natural history of dilated cardiomyopathy.     

The origin of proinflammatory cytokines in patients with idiopathic dilated cardiomyopathy

Proinflammatory cytokines and their receptors are increased in the peripheral blood of patients with heart failure. We measured cytokines and their receptors in systemic artery (SA), coronary sinus (CS) and infra-renal inferior vena cava (IVC), in order to investigate their origin and influential factors. Thirty patients with idiopathic dilated cardiomyopathy were performed echocardiography at admission, and right heart catheterization after stabilization. Blood was drawn from 3 sites for measurement of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and soluble tumor necrosis factor-alpha receptor (sTNFR) I, II. TNF-alpha at CS (3.25 +/- 0.34 pg/mL) was higher than those of SA (1.81 +/- 0.39 pg/mL) and IVC (1.88 +/- 0.38 pg/mL, p<0.05). IL-6 at CS (18.3 +/- 3.8 pg/mL) was higher than that of SA (5.8 +/- 1.2 pg/mL, p<0.01). The levels of sTNFR I, II showed increasing tendency in sequence of SA, IVC and CS. TNF-alpha and sTNFR I, II from all sites were proportional to worsening of functional classes at admission (p<0.05). E/Ea by Doppler study at admission, which reflects left ventricular end-diastolic pressure (LVEDP) was positively correlated with TNF-alpha from SA (R=0.71, p<0.01), CS (R=0.52, p<0.05) and IVC (R=0.46, p<0.05). Thus, elevated LVEDP during decompensation might cause cytokine release from myocardium in patients with idiopathic dilated cardiomyopathy.     

MHC class II genes in Mexican patients with idiopathic dilated cardiomyopathy

The purpose of the present study was to evaluate the relationship between class II major histocompatibility complex (MHC) genes (HLA-DR and HLA-DQB) and the genetic susceptibility to idiopathic dilated cardiomyopathy (IDC) in Mexican patients. The HLA-DR and DQB alleles were analyzed in 53 patients with IDC and 99 ethnically matched healthy controls using the polymerase chain reaction-sequence specific oligonucleotides (PCR-SSO) technique. IDC patients showed increased frequencies of HLA-DR4 (pC=0.02, OR=1.87), HLA-DQB1*0301 (pC=0.02, OR=1.92) and HLA-DQB1*0302 (pC=0.02, OR=1.87) when compared to healthy controls. On the other hand, IDC patients also showed decreased frequencies of HLA-DR11 allele (pC=0.03, OR=0.26) and HLA-DQB1*0201 (pC=0.04, OR=0.41). These data suggest that variation in class II HLA alleles could be a genetic factor involved in the susceptibility to IDC of the Mexican Mestizo population.     

扩张型心肌病IL－6及IL－1活性的初步研究

应用ＭＴＴ比色法及ＣｏｎＡ活化小鼠胸腺细胞增殖法检测了３０例扩张型心肌病（ＤＣＭ）患者及２０例正常人（ＮＣ）的血清白细胞介素６（ＩＬ－６）、白细胞介素１（ＩＬ－１）的活性，结果发现ＤＣＭ患者ＩＬ－６及ＩＬ－１活性均明显高于ＮＣ组（Ｐ＜０．００１，Ｐ＜０．０１）。提示：ＩＬ－６及ＩＬ－１功能紊乱参与了ＤＣＭ的病理过程。     

The role of sarcomere gene mutations in patients with idiopathic dilated cardiomyopathy

We investigated a Danish cohort of 31 unrelated patients with idiopathic dilated cardiomyopathy (IDC), to assess the role that mutations in sarcomere protein genes play in IDC. Patients were genetically screened by capillary electrophoresis single strand conformation polymorphism and subsequently by bidirectional DNA sequencing of conformers in the coding regions of MYH7, MYBPC3, TPM1, ACTC, MYL2, MYL3, TNNT2, CSRP3 and TNNI3. Eight probands carried disease-associated genetic variants (26%). In MYH7, three novel mutations were found; in MYBPC3, one novel variant and two known mutations were found; and in TNNT2, a known mutation was found. One proband was double heterozygous. We find evidence of phenotypic plasticity: three mutations described earlier as HCM causing were found in four cases of IDC, with no history of a hypertrophic phase. Furthermore, one pedigree presented with several cases of classic DCM as well as one case with left ventricular non-compaction. Disease-causing sarcomere gene mutations were found in about one-quarter of IDC patients, and seem to play an important role in the causation of the disease. The genetics is as complex as seen in HCM. Thus, our data suggest that a genetic work-up should include screening of the most prominent sarcomere genes even in the absence of a family history of the disease.     

Enteroviruses and idiopathic dilated cardiomyopathy.

Previous studies have suggested that some cases of idiopathic dilated cardiomyopathy (IDC) are due to persistent viral infection following an episode of viral myocarditis. Viral RNA sequences have recently been detected in material from patients with IDC using molecular biological techniques. We tested 40 samples from recipients' hearts explanted at cardiac transplantation for the presence of enteroviral RNA sequences, using a Northern blotting technique. Material from 19 cases of IDC and 21 cases of non-cardiomyopathic cardiac failure was examined together with Coxsackie-virus-infected neonatal mouse heart as a positive control and non-infected adult mouse heart as a negative control. A sharp band of viral RNA was detected in the positive control sample. No hybridization signal attributable to viral RNA was obtained for the negative control or for any of the test samples. We conclude that the role of enteroviruses in the pathogenesis of cardiomyopathy is not fully established and that further study is warranted.     

Quantitative genomic and antigenomic enterovirus RNA detection in explanted heart tissue samples from patients with end-stage idiopathic dilated cardiomyopathy

Standardized one-step real-time RT-PCR assay detected enterovirus RNA in cardiac biopsy samples from 4 of 20 patients suffering from idiopathic dilated cardiomyopathy (IDCM). The median viral load was 287 copies per microgram of total extracted nucleic acids, with positive- to negative-strand RNA ratios ranging from 2 to 20. These results demonstrate enterovirus persistence in the heart of IDCM patients, characterized by low viral loads and low positive- to negative-RNA ratios.     

Beta1-adrenergic receptor gene polymorphisms in Mexican patients with idiopathic dilated cardiomyopathy

The objective of the study was to evaluate the role of beta1-adrenergic receptor gene polymorphisms (Ser49Gly and Arg389Gly) as susceptibility markers for idiopathic dilated cardiomyopathy (IDC) in Mexican patients. The polymorphisms were analyzed in 47 patients with IDC and 93 ethnically matched healthy controls by polymerase chain reaction-restriction fragment length polymorphism. The Ser49Gly allele and genotype frequencies were similar in patients and healthy controls. On the other hand, the analysis of the Arg389Gly polymorphism showed an increased frequencies of the *Gly allele (pC = 0.022, OR = 2.16) and *Arg/*Gly genotype (pC = 0.027, OR = 2.70) in the group of IDC patients when compared to healthy controls. The data suggest that Arg389Gly polymorphism could be involved in the genetic susceptibility to develop IDC in Mexicans.     

Dystrophin analysis in idiopathic dilated cardiomyopathy.

Idiopathic dilated cardiomyopathy (DCM) is characterised by ventricular dilatation and impaired systolic function resulting in congestive heart failure and frequently death. A dilated cardiomyopathy is common in patients with symptomatic Duchenne/Becker muscular dystrophy, a disease caused by dystrophin gene defects. However, cardiomyopathy is rarely the predominant clinical feature of this form of muscular dystrophy. To determine whether dystrophin gene defects might account for a significant number of patients with apparently isolated idiopathic DCM, we performed dystrophin gene analysis in 27 DCM patients, who were ascertained as part of a prospective study on idiopathic DCM. No dystrophin gene defects were found in our patients, whose average age was 50 years. These data suggest that dystrophin defects are not a common cause of idiopathic DCM in this age group in the absence of skeletal muscle cramps or weakness.     

Analysis of TCR Vbeta repertoire and cytokine gene expression in patients with idiopathic dilated cardiomyopathy

Although the etiopathogenesis of idiopathic dilated cardiomyopathy (IDC) is still unclear, it is widely accepted that a complex interplay between viral infections and immune mechanisms is the basis of disease genesis. Previously, we showed that heart-infiltrating T cells of patients suffering from acute, fulminant Coxsackie virus B3+-IDC shared a preferential usage of three variable gene segments of the T cell receptor beta chain-(TCR-Vbeta) encoding families Vbeta3, 7 and 13.1. This indicated the possible presence of a superantigen-driven immune response. Here, we further investigated the IDC immunological scenario by analysing different phenotypes of heart-infiltrating cells: TCR repertoires, cytokine expression and presence of enterovirus-specific antigens. IDC patients who underwent heart transplantation at different times after the onset of heart failure were studied. A cardiac infiltrate of CD4+ and CD8+ T cells was present together with activated macrophages. Furthermore, the same Vbeta gene families, previously found to be skewed in hearts from fulminant cases of CVB3+-IDC, together with two additional Vbeta gene families, Vbeta1 and 5B, were increased. IL-1beta, IL-2, IL-6 and IFN-gamma were expressed in the myocardium while others, like IL-4 were not. In conclusion, an orchestrated complex of immune mechanisms seems to be the basis of IDC etiopathogenesis.     

Induction of cardiomyopathy in severe combined immunodeficiency mice by transfer of lymphocytes from patients with idiopathic dilated cardiomyopathy

Growing evidence suggests that autoimmune mechanisms play an important role in the pathogenesis of idiopathic dilated cardiomyopathy (DCM). The aim of the study was to evaluate the effects of transfer of lymphocytes from patients with DCM into severe combined immunodeficiency (SCID) mice on the heart structure and function. Thirty CB-17 SCID (6-8 weeks old) mice were used and divided into 3 groups (n = 10). Mice were injected intraperitoneally with up to 25 x 10(6) peripheral blood lymphocytes (PBL) from either patients with DCM which contain human autoantibodies against cardiac beta1-adrenergic receptors and M2-muscarinic receptors (DCM group) or PBL from healthy controls (control-H group). Ten mice did not receive any injections and were used as baseline controls (control-N group). Echocardiography and morphological studies were performed seventy five days after the transfer. Results showed that in DCM group, left ventricle dimensions (LVD) in diastole were increased (4.2 +/- 0.1mm) as compared to both control-H group (3.8 +/- 0.1mm) and control-N group (3.6 +/- 0.1 mm) (p < 0.01). Further, there was a trend for increased LVD in systole. Fractional shortening was not different between groups. Histological evaluation revealed accumulation of human lymphocytes in the capillaries and scarce infiltration of the lymphocytes in the hearts from DCM group. Diffuse fibrosis was significant increased in DCM mice as compared to mice receiving PBL from normal subjects (2.2 +/- 0.3% vs. 0.8 +/- 0.1%, p < 0.01). In conclusion, transfer of the PBL from the patients with DCM was able to induce early stage of heart dilatation in SCID mice. These data provide for the first time the direct evidence supporting that the autoimmune mechanism is important in the pathogenesis of human DCM.     

干扰素基因多态性与扩张型心肌病的相关研究

目的探讨北方地区汉族人干扰素（IFN-r）基因单核苷酸多态性（SNP）与扩张型心肌病（IDC）的相关性。方法应用顺序特异性引物和聚合酶链反应（PCR-SSP）技术，检测了31例IDC患者（患者组）和35例健康献血者（对照组）中IFN-r启动子基因874位点的多态性变化。结果结果表明IDC组IFN-r（874T）等位基因频率（32，26％）显著高于对照组IFN-r（11．43％），P〈0．05，两组之间比较差异有显著性意义，提示该等位基因频率增高与IDC相关。结论我国北方地区汉族人IFN-r基因874T位点的多态性在IDC的疾病病程中有重要作用，IFN-r启动子基因874T可能是IDC的易感性基因之一。     

HLA and immunoglobulin polymorphisms in idiopathic dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is an idiopathic heart muscle disorder. The presence of circulating cardiac antibodies and the association with HLA-DR4 are consistent with autoimmune pathogenesis in a subset of patients. Sixty-eight DCM patients and 277 controls were typed for IgG heavy-chain constant region (Gm) and kappa light-chain (Km) allotypes. All patients and 210 of the 277 controls were HLA-DR typed. The Gm (1, 3, 17; 23; 5*, 21, 28) phenotype was overrepresented in DCM compared with controls (25% vs 13%, p = 0.0139, pc = NS, RR = 2.23). The frequency of this phenotype was higher in patients with younger age at onset, shorter symptom duration, and among those who were positive for cardiac as well as for non-organ-specific autoantibodies than in controls. A higher frequency of the Gm (1, +/- 2, 3, 17; +/- 23; 5*, 21, 28) heterozygous phenotypes was also found in DCM compared to controls (40.91% vs 26.89%; p = 0.02, pc = 0.04, RR = 1.88). The finding of Gm heterozygosity in DCM was associated with serum positivity for cardiac antibodies. A higher proportion of DCM patients were positive for both the Gm (1, 3, 17; 23; 5*, 21, 28) phenotype and HLA-DR4 compared to normals (3/68 vs 0/210; p = 0.04, RR = 22.50).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pulsed Doppler echocardiographic study of left ventricular diastolic function in patients with idiopathic dilated cardiomyopathy

Dilated cardiomyopathy is basically regarded as a disease of left ventricular systolic dysfunction. There are only a few studies evaluating diastolic function in patients with dilated cardiomyopathy. To assess the LV diastolic function, 25 patients with idiopathic dilated cardiomyopathy and 20 age and sex matched normal subjects were studied with transmitral spectral tracings derived from pulsed Doppler echocardiography. All cardiomyopathy patients were in New York Heart Association class III to IV with dilated left ventricles and reduced systolic function (mean ejection fraction of 36.6 +/- 6.7 Vs 65 +/- 6 in normal subjects, p < 0.001). Patients with cardiomyopathy demonstrated an increased ratio of early to late diastolic velocity (E/A) (1.89 +/- 0.59 Vs 1.50 +/- 0.27 m/sec, p < 0.05), short deceleration time (E-E/2) (57.05 +/- 13.36 Vs 70.20 +/- 16.56 msec, p < 0.01) and short isovolumic relaxation time (IVRT) (53.5 +/- 22.7 Vs 72 +/- 12 msec, p < 0.05) as compared to normal subjects. The early filling fraction (EFF) was higher (0.71 +/- 0.11 Vs 0.66 +/- 0.06, p < 0.05) and atrial filling fraction (AFF) was lower (0.28 +/- 0.11 Vs 0.33 +/- 0.06, p < 0.05) in cardiomyopathy patients than in normal subjects. Our observations in a select group of dilated cardiomyopathy patients with advanced disease demonstrate a restrictive pattern on pulsed Doppler echocardiography.     

More severe cellular phenotype in human idiopathic dilated cardiomyopathy compared to ischemic heart disease

Activation of the β-adrenergic receptor (βAR) pathway is the main mechanism of the heart to increase cardiac output via protein kinase A (PKA)-mediated phosphorylation of cellular target proteins, and perturbations therein may contribute to cardiac dysfunction in heart failure. In the present study a comprehensive analysis was made of mediators of the βAR pathway, myofilament properties and cardiac structure in patients with idiopathic (IDCM; n = 13) and ischemic (ISHD; n = 10) cardiomyopathy in comparison to non-failing hearts (donor; n = 10) for the following parameters: βAR density, G-coupled receptor kinases 2 and 5, stimulatory and inhibitory G-proteins, phosphorylation of myofilament targets of PKA, protein phosphatase 1, phospholamban, SERCA2a and single myocyte contractility. All parameters exhibited the expected alterations of heart failure, but for most of them the extent of alteration was greater in IDCM than in ISHD. Histological analysis also revealed higher collagen in IDCM compared to ISHD. Alterations in the βAR pathway are more pronounced in IDCM than in ISHD and may reflect sequential changes in cellular protein composition and function. Our data indicate that cellular dysfunction is more severe in IDCM than in ISHD.     

Very high frequency oscillations in the heart rate and blood pressure of heart transplant patients

The authors studied the recently reported very high frequency (VHF) peaks in the heart rate (HR) and blood pressure (BP) power spectra of heart transplant (HT) patients. These VHF peaks appear at frequencies much higher than the respiratory frequency, in addition to the typical low-frequency and high-frequency peaks. Twenty-five recordings obtained from 13 male HT patients (0.5–65 months following surgery) were compared with recordings from 14 normal male subjects. The ECG, continuous BP and respiration were recorded during 45 min of supine rest. Eight recordings from HT patients were excluded owing to arrhythmias. Spectral analysis was performed on all other recordings. VHF peaks were found in the spectra of both BP and HR in nine recordings obtained from six HT patients. In some cases, the power in the VHF peaks was markedly higher than that of the high-frequency peak. No VHF peaks were observed in eight recordings obtained from four HT patients or in recording from any of the normal subjects. No correlation was found between the incidence of VHF peaks and time after transplant. It was proved that the VHF peaks were not artifactual, and their significance within the framework of the theory of communication systems is discussed. The presence of those peaks was attributed to vagal denervation.     

CTLA-4基因多态性与特发性扩张型心肌病的相关性

目的包括细胞和体液免疫在内的自身免疫机制至少参与了部分特发性扩张型心肌病(Idiopathicdilatedcar-diomyopathy,IDC)患者的发病,且前者介导的心肌损害在IDC中更重要。CTLA-4是特异性细胞免疫的负性调节因子。本研究旨在探讨CTLA-4基因启动子-318C/T、外显子A/G多态性及3′非翻译区(AT)n微卫星多态性与IDC及血清可溶性CT-LA-4(sCTLA-4)水平的相关性。方法采用聚合酶链反应-限制性片段长度多态性(Polymerasechainreaction-restrictionfragmentlengthpolymorphisms,PCR-RFLP)方法分析黑龙江省无血缘关系汉族人群(包括72例IDC患者,100例正常健康人)CTLA-4基因-318C/T、49位点A/G多态性及3′微卫星多态性;ELISA法检测血清sCTLA-4水平。综合分析CTLA-4基因型频率、等位基因频率与IDC及sCTLA-4水平的相关性。结果IDC组外显子1GG基因型和G等位基因频率显著高于正常对照组(P=0.012,P=0.008);3′非翻译区共发现18种等位基因,106bp等位基因频率在IDC患者中显著增高(22.22%vs1%,P=0.0002,OR=23.56,95%CI9.65~83.74);两组间-318C/T多态性分布无统计学差异。与对照组相比,IDC组sCTLA-4水平显著升高[(1.87±1.06)μg/L比(0.54±0.19)μg/L,P<0.05];直线回归分析显示,IDC组GG基因型及G等位基因频率与血清sCTLA-4水平(r=0.57,P=0.021)显著相关,而AA、A/G基因型及A等位基因频率与sCTLA-4水平无相关性。启动子-318C/T多态性及3′非翻译区(AT)n微卫星多态性与sCTLA-4水平的亦无相关性。结论CTLA-4基因外显子1A49→G变异与IDC相关,携带G等位基因者易患IDC,其机制可能为该多态性造成CTLA-4信号肽中编码苏氨酸和甘氨酸的替换,从而影响蛋白翻译后加工、修饰,使sCTLA-4功能发生变化。提示3′末端非翻译区(AT)n重复序列中106bp等位基因可能是IDC的易感基因。