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MacRae CA, Birchmeier W, Thierfelder L. Arrhythmogenic right ventricular cardiomyopathy: moving toward mechanism. J Clin Invest 2006; 116:1825-8. [PMID: 16823481 PMCID: PMC1483166 DOI: 10.1172/jci29174] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Mutations in genes encoding desmosomal proteins have been identified as the major cause of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC), in which the right ventricle is "replaced" by fibrofatty tissue, resulting in lethal arrhythmias. In this issue of the JCI, Garcia-Gras et al. demonstrate that cardiac-specific loss of the desmosomal protein desmoplakin is sufficient to cause nuclear translocation of plakoglobin, upregulation of adipogenic genes in vitro, and a shift from a cardiomyocyte to an adipocyte cell fate in vivo (see the related article beginning on page 2012). This evidence for potential Wnt/beta-catenin signaling defects sets the scene for a comprehensive exploration of the contributions of this pathway to the pathophysiology of ARVC, not only through perturbation of cardiac patterning and development, but also through effects on myocardial differentiation and physiology.
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van Kimmenade RR, Januzzi JL, Ellinor PT, Sharma UC, Bakker JA, Low AF, Martinez A, Crijns HJ, MacRae CA, Menheere PP, Pinto YM. Utility of amino-terminal pro-brain natriuretic peptide, galectin-3, and apelin for the evaluation of patients with acute heart failure. J Am Coll Cardiol 2006; 48:1217-24. [PMID: 16979009 DOI: 10.1016/j.jacc.2006.03.061] [Citation(s) in RCA: 411] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 01/03/2006] [Accepted: 03/28/2006] [Indexed: 01/11/2023]
Abstract
OBJECTIVES This study sought to explore the role of new biomarkers in heart failure (HF). BACKGROUND We investigated the utility of novel serum markers alone or together with natriuretic peptide testing for diagnosis and short-term prognosis estimation in subjects with acute HF. METHODS Plasma levels of amino-terminal pro-brain natriuretic peptide (NT-proBNP), apelin, and galectin-3 were measured in 599 patients presenting with dyspnea at the emergency department, of which 209 (35%) had acute HF. RESULTS The NT-proBNP was superior to either apelin or galectin-3 for diagnosis of acute HF, although galectin-3 levels were significantly higher in subjects with HF compared with those without. Receiver operating characteristic analysis for mortality prediction showed that, for 60-day prognosis, galectin-3 had the greatest area under the curve (AUC) at 0.74 (p = 0.0001), whereas NT-proBNP and apelin had an AUC of 0.67 (p = 0.009) and 0.54 (p = 0.33). In a multivariate logistic regression analysis, an elevated level of galectin-3 was the best independent predictor of 60-day mortality (odds ratio 10.3, p < 0.01) or the combination of death/recurrent HF within 60 days (odds ratio 14.3, p < 0.001). The Kaplan-Meier analyses showed that the combination of an elevated galectin-3 with NT-proBNP was a better predictor of mortality than either of the 2 markers alone. CONCLUSIONS Our data show potential utility of galectin-3 as a useful marker for evaluation of patients with suspected or proven acute HF, whereas apelin measurement was not useful for these indications. Moreover, the combination of galectin-3 with NT-proBNP was the best predictor for prognosis in subjects with acute HF.
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Ellinor PT, Petrov-Kondratov VI, Zakharova E, Nam EG, MacRae CA. Potassium channel gene mutations rarely cause atrial fibrillation. BMC MEDICAL GENETICS 2006; 7:70. [PMID: 16887036 PMCID: PMC1559598 DOI: 10.1186/1471-2350-7-70] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 08/03/2006] [Indexed: 11/10/2022]
Abstract
Background Mutations in several potassium channel subunits have been associated with rare forms of atrial fibrillation. In order to explore the role of potassium channels in inherited typical forms of the arrhythmia, we have screened a cohort of patients from a referral clinic for mutations in the channel subunit genes implicated in the arrhythmia. We sought to determine if mutations in KCNJ2 and KCNE1-5 are a common cause of atrial fibrillation. Methods Serial patients with lone atrial fibrillation or atrial fibrillation with hypertension were enrolled between June 1, 2001 and January 6, 2005. Each patient underwent a standardized interview and physical examination. An electrocardiogram, echocardiogram and blood sample for genetic analysis were also obtained. Patients with a family history of AF were screened for mutations in KCNJ2 and KCNE1-5 using automated sequencing. Results 96 patients with familial atrial fibrillation were enrolled. Eighty-three patients had lone atrial fibrillation and 13 had atrial fibrillation and hypertension. Patients had a mean age of 56 years at enrollment and 46 years at onset of atrial fibrillation. Eighty-one percent of patients had paroxysmal atrial fibrillation at enrollment. Unlike patients with an activating mutation in KCNQ1, the patients had a normal QTc interval with a mean of 412 ± 42 ms. Echocardiography revealed a normal mean ejection fraction of 62.0 ± 7.2 % and mean left atrial dimension of 39.9 ± 7.0 mm. A number of common polymorphisms in KCNJ2 and KCNE1-5 were identified, but no mutations were detected. Conclusion Mutations in KCNJ2 and KCNE1-5 rarely cause typical atrial fibrillation in a referral clinic population.
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Milan DJ, Jones IL, Ellinor PT, MacRae CA. In vivo recording of adult zebrafish electrocardiogram and assessment of drug-induced QT prolongation. Am J Physiol Heart Circ Physiol 2006; 291:H269-73. [PMID: 16489111 DOI: 10.1152/ajpheart.00960.2005] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the last decade the zebrafish has become a major model organism for the study of development and organogenesis. To maximize the experimental utility of this organism, it will be important to establish methods for adult phenotyping. We previously proposed that the embryonic zebrafish may be useful in high-throughput screening for drug-induced cardiotoxicity. We now describe a method for the reproducible recording of the adult zebrafish ECG and illustrate its application in the investigation of QT-prolonging drugs. Zebrafish ECGs were obtained by inserting two needle electrodes through the ventral epidermis. Fish were perfused orally, and motion artifacts were eliminated with a paralytic dose of μ-conotoxin GIIIB. Test compounds were delivered via the perfusion system. Without a means of hydration and oxygenation, the fish succumb rapidly. The use of a perfusion system allowed stable recording for >6 h. Baseline conduction intervals were as follows: PR, 66 ms (SD 14); QRS, 34 ms (SD 11); QT, 242 ms (SD 54); and R-R, 398 ms (SD 77). The known QT-prolonging agents astemizole, haloperidol, pimozide, and terfenadine caused corrected QT increases of 18% (SD 9), 16% (SD 11), 17% (SD 9), and 11% (SD 6), respectively. The control drugs clonidine, penicillin and propranolol did not prolong the corrected QT interval. In conclusion, perfusion and muscular paralysis allows stable, low-noise recording of zebrafish ECGs. Agents known to cause QT prolongation in humans caused QT prolongation in fish in each case. The development of rigorous tools for the phenotyping of adult zebrafish will complement the high-throughput assays currently under development for embryonic and larval fish.
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Ellinor PT, Sasse-Klaassen S, Probst S, Gerull B, Shin JT, Toeppel A, Heuser A, Michely B, Yoerger DM, Song BS, Pilz B, Krings G, Coplin B, Lange PE, Dec GW, Hennies HC, Thierfelder L, MacRae CA. A novel locus for dilated cardiomyopathy, diffuse myocardial fibrosis, and sudden death on chromosome 10q25-26. J Am Coll Cardiol 2006; 48:106-11. [PMID: 16814656 DOI: 10.1016/j.jacc.2006.01.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 12/30/2005] [Accepted: 01/09/2006] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We sought to identify the genetic locus for an inherited form of dilated cardiomyopathy (DCM) that is characterized by diffuse myocardial fibrosis and sudden death. BACKGROUND Genetic studies have mapped multiple loci for DCM, which is a major cause of nonischemic heart failure; however, the genes responsible for the majority of cases have yet to be identified. METHODS Sixty-six family members were evaluated by 12-lead electrocardiogram (ECG), echocardiogram, and laboratory studies. Individuals with echocardiographically documented DCM were defined as affected. Subjects were considered unaffected if they were older than 20 years of age, had a normal ECG and echocardiogram, no personal history of heart failure, and had no affected offspring. Genotyping was performed using polymorphic markers. RESULTS Genome-wide linkage analysis identified a novel locus for this inherited phenotype on chromosome 10q25.3-q26.13. Peak two-point logarithm of the odds scores >3.0 were obtained independently with each family using the markers D10S1773 and D10S1483, respectively. Haplotype analyses defined a critical interval of 14.0 centiMorgans between D10S1237 and D10S1723, corresponding to a physical distance of 9.5 megabases. Multipoint linkage analyses confirmed this interval and generated a peak logarithm of the odds score of 8.2 indicating odds of >100,000,000:1 in favor of this interval as the location of the gene defect responsible for DCM in these families. CONCLUSIONS We have mapped a novel locus for cardiomyopathy, diffuse myocardial fibrosis, and sudden death to chromosome 10q25-q26. The identification of the causative gene in this interval will be an important step in understanding the fundamental mechanisms of heart failure and sudden death.
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Ellinor PT, Low A, Patton KK, Shea MA, MacRae CA. C-Reactive protein in lone atrial fibrillation. Am J Cardiol 2006; 97:1346-50. [PMID: 16635609 DOI: 10.1016/j.amjcard.2005.11.052] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 11/16/2005] [Accepted: 11/16/2005] [Indexed: 11/21/2022]
Abstract
An inflammatory cause of atrial fibrillation (AF) has been proposed on the basis of the presence of lymphocytic infiltrates in the biopsy results of patients with lone AF, alterations of C-reactive protein (CRP) and interleukin-6 levels in subjects with AF, and the time course of postoperative AF. Many previous studies exploring inflammatory factors in AF have been confounded by concomitant medical illnesses. Subjects with lone AF provide a unique opportunity to eliminate the effects of associated conditions. We therefore sought to determine CRP levels in homogenous cohorts of patients with lone AF or AF and hypertension. One hundred twenty-one subjects with lone AF, 52 subjects with AF and hypertension, and 75 control subjects were enrolled and studied. Plasma CRP levels were determined using a commercially available immunoassay. There was no significant difference in CRP levels between subjects with lone AF and controls (1.34 vs 1.21 mg/L, p = 0.18). CRP levels in subjects with AF and hypertension were elevated compared with those of controls and those of subjects with lone AF, although this difference was attributable to increased body mass indexes. CRP levels were not elevated in subjects with lone AF compared with controls. In conclusion, these findings clarify previous observations of elevations in CRP levels in subjects with AF and suggest that this marker of systemic inflammation is associated not with the arrhythmia per se, but rather with underlying cardiovascular disease.
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Milan DJ, Giokas AC, Serluca FC, Peterson RT, MacRae CA. Notch1b and neuregulin are required for specification of central cardiac conduction tissue. Development 2006; 133:1125-32. [PMID: 16481353 DOI: 10.1242/dev.02279] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Normal heart function is critically dependent on the timing and coordination provided by a complex network of specialized cells: the cardiac conduction system. We have employed functional assays in zebrafish to explore early steps in the patterning of the conduction system that previously have been inaccessible. We demonstrate that a ring of atrioventricular conduction tissue develops at 40 hours post-fertilization in the zebrafish heart. Analysis of the mutant cloche reveals a requirement for endocardial signals in the formation of this tissue. The differentiation of these specialized cells, unlike that of adjacent endocardial cushions and valves, is not dependent on blood flow or cardiac contraction. Finally, both neuregulin and notch1b are necessary for the development of atrioventricular conduction tissue. These results are the first demonstration of the endocardial signals required for patterning central `slow' conduction tissue, and they reveal the operation of distinct local endocardial-myocardial interactions within the developing heart tube.
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Burns CG, MacRae CA. Purification of hearts from zebrafish embryos. Biotechniques 2006; 40:274, 276, 278 passim. [PMID: 16568816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023] Open
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Milan DJ, MacRae CA. Animal models for arrhythmias. Cardiovasc Res 2006; 67:426-37. [PMID: 16009355 DOI: 10.1016/j.cardiores.2005.06.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 05/31/2005] [Accepted: 06/06/2005] [Indexed: 11/20/2022] Open
Abstract
The complex pathophysiology of human arrhythmias has proven difficult to model. Direct correlations between the traditional arrhythmia mechanisms, including abnormal excitability, conduction, or repolarization and underlying molecular or cellular biology are poorly defined, as the primary etiologies of many human arrhythmias remain unknown. Since the causes of several arrhythmic syndromes have been identified, genetic models reproducing the mechanisms of these arrhythmias have become feasible. Initial murine modeling has revealed that in many cases the pathophysiology of the respective human disease is more complex than had been suspected. Insights from human genetic studies and animal models strongly suggest that the primary molecular defects may contribute at many stages in the causal chain leading to arrhythmia. The comprehensive analysis of each arrhythmia will require knowledge not only of the membrane effects of the primary defects, but also downstream intracellular signals, the developmental results of these perturbations, and the integration of compensatory responses and environmental factors. Precise modeling will require not only the mutation of specific residues in known disease genes, but also the systematic study of each of the many steps in arrhythmogenesis. Ultimately, such models will enable unbiased screens for disease mechanisms and novel therapies.
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Ellinor PT, Yoerger DM, Ruskin JN, MacRae CA. Familial aggregation in lone atrial fibrillation. Hum Genet 2005; 118:179-84. [PMID: 16133178 DOI: 10.1007/s00439-005-0034-8] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 07/08/2005] [Indexed: 11/24/2022]
Abstract
Atrial fibrillation (AF) is the most common clinical arrhythmia and a major risk factor for stroke. To investigate the role of genetic factors in a typical clinical population, we determined the extent of familial aggregation in patients with lone AF. To estimate the relative risk to family members, the prevalence of AF for each class of relative was compared to the prevalence in the comparable age and sex group from the general population. Family members had an increased relative risk of AF compared to the general population (risk ratio; 95% confidence intervals): sons (8.1; 2.0-32), daughters (9.5; 1.3-67), brothers (70; 47-102), sisters (34; 14-80), mothers (4.0; 2.5-6.5) and fathers (2.0; 1.2-3.6). Relatives of probands with lone AF are at a substantially increased risk of developing this arrhythmia suggesting a Mendelian genetic contribution to the etiology of this common trait.
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Low AF, O'Donnell CJ, Kathiresan S, Everett B, Chae CU, Shaw SY, Ellinor PT, MacRae CA. Aging syndrome genes and premature coronary artery disease. BMC MEDICAL GENETICS 2005; 6:38. [PMID: 16262891 PMCID: PMC1289285 DOI: 10.1186/1471-2350-6-38] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2005] [Accepted: 10/31/2005] [Indexed: 01/01/2023]
Abstract
Background Vascular disease is a feature of aging, and coronary vascular events are a major source of morbidity and mortality in rare premature aging syndromes. One such syndrome is caused by mutations in the lamin A/C (LMNA) gene, which also has been implicated in familial insulin resistance. A second gene related to premature aging in man and in murine models is the KLOTHO gene, a hypomorphic variant of which (KL-VS) is significantly more common in the first-degree relatives of patients with premature coronary artery disease (CAD). We evaluated whether common variants at the LMNA or KLOTHO genes are associated with rigorously defined premature CAD. Methods We identified 295 patients presenting with premature acute coronary syndromes confirmed by angiography. A control group of 145 patients with no evidence of CAD was recruited from outpatient referral clinics. Comprehensive haplotyping of the entire LMNA gene, including the promoter and untranslated regions, was performed using a combination of TaqMan® probes and direct sequencing of 14 haplotype-tagging single nucleotide polymorphisms (SNPs). The KL-VS variant of the KLOTHO gene was typed using restriction digest of a PCR amplicon. Results Two SNPs that were not in Hardy Weinberg equilibrium were excluded from analysis. We observed no significant differences in allele, genotype or haplotype frequencies at the LMNA or KLOTHO loci between the two groups. In addition, there was no evidence of excess homozygosity at the LMNA locus. Conclusion Our data do not support the hypothesis that premature CAD is associated with common variants in the progeroid syndrome genes LMNA and KLOTHO.
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Shin JT, Priest JR, Ovcharenko I, Ronco A, Moore RK, Burns CG, MacRae CA. Human-zebrafish non-coding conserved elements act in vivo to regulate transcription. Nucleic Acids Res 2005; 33:5437-45. [PMID: 16179648 PMCID: PMC1236720 DOI: 10.1093/nar/gki853] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Whole genome comparisons of distantly related species effectively predict biologically important sequences--core genes and cis-acting regulatory elements (REs)--but require experimentation to verify biological activity. To examine the efficacy of comparative genomics in identification of active REs from anonymous, non-coding (NC) sequences, we generated a novel alignment of the human and draft zebrafish genomes, and contrasted this set to existing human and fugu datasets. We tested the transcriptional regulatory potential of candidate sequences using two in vivo assays. Strict selection of non-genic elements which are deeply conserved in vertebrate evolution identifies 1744 core vertebrate REs in human and two fish genomes. We tested 16 elements in vivo for cis-acting gene regulatory properties using zebrafish transient transgenesis and found that 10 (63%) strongly modulate tissue-specific expression of a green fluorescent protein reporter vector. We also report a novel quantitative enhancer assay with potential for increased throughput based on normalized luciferase activity in vivo. This complementary system identified 11 (69%; including 9 of 10 GFP-confirmed elements) with cis-acting function. Together, these data support the utility of comparative genomics of distantly related vertebrate species to identify REs and provide a scaleable, in vivo quantitative assay to define functional activity of candidate REs.
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Burns CG, Milan DJ, Grande EJ, Rottbauer W, MacRae CA, Fishman MC. High-throughput assay for small molecules that modulate zebrafish embryonic heart rate. Nat Chem Biol 2005; 1:263-4. [PMID: 16408054 DOI: 10.1038/nchembio732] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Accepted: 08/23/2005] [Indexed: 12/22/2022]
Abstract
To increase the facility and throughput of scoring phenotypic traits in embryonic zebrafish, we developed an automated micro-well assay for heart rate using automated fluorescence microscopy of transgenic embryos expressing green fluorescent protein in myocardium. The assay measures heart rates efficiently and accurately over a large linear dynamic range, and it rapidly characterizes dose dependence and kinetics of small molecule-induced changes in heart rate. This is the first high-throughput micro-well assay for organ function in an intact vertebrate.
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Milan DJ, Giokas AC, Peterson RT, MacRae CA. Neuregulin but not endothelin signaling is required for atrioventricular conduction tissue development. Heart Rhythm 2005. [DOI: 10.1016/j.hrthm.2005.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mahon NG, Murphy RT, MacRae CA, Caforio ALP, Elliott PM, McKenna WJ. Echocardiographic evaluation in asymptomatic relatives of patients with dilated cardiomyopathy reveals preclinical disease. Ann Intern Med 2005; 143:108-15. [PMID: 16027452 DOI: 10.7326/0003-4819-143-2-200507190-00009] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Idiopathic dilated cardiomyopathy is often familial, and apparently healthy relatives may have latent, early, or undiagnosed established disease. OBJECTIVE To determine the prevalence and natural history of asymptomatic cardiac abnormalities among sampled relatives of unselected patients referred for management of dilated cardio-myopathy. DESIGN Prospective cohort study. PATIENTS 767 asymptomatic relatives of 189 consecutive unselected patients with dilated cardiomyopathy. MEASUREMENTS Clinical evaluation, including history, physical examination, electrocardiography, and echocardiography, was performed. Participants were classified in accordance with published echocardiographic criteria. Sampled relatives who did not have evidence of dilated cardiomyopathy at the initial evaluation were followed for a median of 57 months (range, 1 to 133 months). RESULTS Of the 767 patients evaluated, 592 (77.2%) were assessed as healthy, 35 (4.6% [95% CI, 3.7% to 7.6%]) had dilated cardiomyopathy, 119 (15.5% [CI, 12.5% to 18.8%]) had left ventricular enlargement without systolic dysfunction, and 21 (2.7% [CI, 1.9% to 4.9%]) had depressed fractional shortening without ventricular dilatation. At follow-up, progression to dilated cardiomyopathy occurred in 13 (10%) relatives with left ventricular enlargement or depressed fractional shortening versus 3 (1.3%) healthy relatives. In a multivariate model, only left ventricular enlargement or depressed fractional shortening independently predicted progression to dilated cardiomyopathy (hazard ratio, 10.0 [CI, 2.8 to 35.5]; P < 0.001). LIMITATIONS Because relatives had to be willing to participate and be available geographically, selection bias may have occurred. CONCLUSION Treatable asymptomatic dilated cardiomyopathy was identified in 4.6% of asymptomatic relatives. In addition, left ventricular enlargement and depressed fractional shortening were common in asymptomatic relatives of patients with dilated cardiomyopathy and were associated with a statistically significant medium-term risk for disease progression. Evaluation of relatives of patients with cardiomyopathy is recommended.
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Gerull B, Heuser A, Wichter T, Paul M, Basson CT, McDermott DA, Lerman BB, Markowitz SM, Ellinor PT, MacRae CA, Peters S, Grossmann KS, Drenckhahn J, Michely B, Sasse-Klaassen S, Birchmeier W, Dietz R, Breithardt G, Schulze-Bahr E, Thierfelder L. Mutations in the desmosomal protein plakophilin-2 are common in arrhythmogenic right ventricular cardiomyopathy. Nat Genet 2004; 36:1162-4. [PMID: 15489853 DOI: 10.1038/ng1461] [Citation(s) in RCA: 569] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Accepted: 09/28/2004] [Indexed: 01/15/2023]
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with fibrofatty replacement of cardiac myocytes, ventricular tachyarrhythmias and sudden cardiac death. In 32 of 120 unrelated individuals with ARVC, we identified heterozygous mutations in PKP2, which encodes plakophilin-2, an essential armadillo-repeat protein of the cardiac desmosome. In two kindreds with ARVC, disease was incompletely penetrant in most carriers of PKP2 mutations.
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Friedrich EB, Liu E, Sinha S, Cook S, Milstone DS, MacRae CA, Mariotti M, Kuhlencordt PJ, Force T, Rosenzweig A, St-Arnaud R, Dedhar S, Gerszten RE. Integrin-linked kinase regulates endothelial cell survival and vascular development. Mol Cell Biol 2004; 24:8134-44. [PMID: 15340074 PMCID: PMC515035 DOI: 10.1128/mcb.24.18.8134-8144.2004] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Integrin-linked kinase (ILK) is a phosphoinositide 3-kinase-dependent serine/threonine kinase that interacts with beta integrins. Here we show that endothelial cell (EC)-specific deletion of ILK in mice confers placental insufficiency with decreased labyrinthine vascularization, yielding no viable offspring. Deletion of ILK in zebra fish using antisense morpholino oligonucleotides results in marked patterning abnormalities of the vasculature and is similarly lethal. To dissect potential mechanisms responsible for these phenotypes, we performed ex vivo deletion of ILK from purified EC of adult mice. We observed downregulation of the active-conformation of beta1 integrins with a striking increase in EC apoptosis associated with activation of caspase 9. There was also reduced phosphorylation of the ILK kinase substrate, Akt. However, phenotypic rescue of ILK-deficient EC by wild-type ILK, but not by a constitutively active mutant of Akt, suggests regulation of EC survival by ILK in an Akt-independent manner. Thus, endothelial ILK plays a critical role in vascular development through integrin-matrix interactions and EC survival. These data have important implications for both physiological and pathological angiogenesis.
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Peterson RT, Shaw SY, Peterson TA, Milan DJ, Zhong TP, Schreiber SL, MacRae CA, Fishman MC. Chemical suppression of a genetic mutation in a zebrafish model of aortic coarctation. Nat Biotechnol 2004; 22:595-9. [PMID: 15097998 DOI: 10.1038/nbt963] [Citation(s) in RCA: 324] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Accepted: 02/13/2004] [Indexed: 11/08/2022]
Abstract
Conventional drug discovery approaches require a priori selection of an appropriate molecular target, but it is often not obvious which biological pathways must be targeted to reverse a disease phenotype. Phenotype-based screens offer the potential to identify pathways and potential therapies that influence disease processes. The zebrafish mutation gridlock (grl, affecting the gene hey2) disrupts aortic blood flow in a region and physiological manner akin to aortic coarctation in humans. Here we use a whole-organism, phenotype-based, small-molecule screen to discover a class of compounds that suppress the coarctation phenotype and permit survival to adulthood. These compounds function during the specification and migration of angioblasts. They act to upregulate expression of vascular endothelial growth factor (VEGF), and the activation of the VEGF pathway is sufficient to suppress the gridlock phenotype. Thus, organism-based screens allow the discovery of small molecules that ameliorate complex dysmorphic syndromes even without targeting the affected gene directly.
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MacRae CA, Fishman MC. Zebrafish: the complete cardiovascular compendium. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2003; 67:301-7. [PMID: 12858553 DOI: 10.1101/sqb.2002.67.301] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Wang TJ, Nam BH, D'Agostino RB, Wolf PA, Lloyd-Jones DM, MacRae CA, Wilson PW, Polak JF, O'Donnell CJ. Carotid intima-media thickness is associated with premature parental coronary heart disease: the Framingham Heart Study. Circulation 2003; 108:572-6. [PMID: 12874190 DOI: 10.1161/01.cir.0000081764.35431.de] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A family history of coronary heart disease (CHD) is an independent risk factor for cardiovascular events. However, the mechanisms underlying this susceptibility have not been fully elucidated. We hypothesized that an important mediator of the familial predisposition to CHD is subclinical atherosclerosis, which is detectable by noninvasive imaging. METHODS AND RESULTS We studied 1662 subjects (mean age 57, 51% women) in the Framingham Offspring Study who underwent carotid ultrasonography and had both biological parents in the original (parental) cohort. Parental CHD events were validated prospectively by a physician endpoint committee. The associations of carotid intima-media thickness (IMT) with premature parental CHD (occurring before age 60) and any parental CHD (no age restriction) were examined in age- and multivariable-adjusted analyses. Age-adjusted mean internal carotid IMT was higher in subjects who had at least one parent with premature CHD than in those without a validated parental history of premature CHD (men 1.13 versus 1.04 mm, P<0.01; women 0.92 versus 0.85 mm, P=0.03). In both sexes, these differences remained significant after adjustment for cardiovascular risk factors. In analyses without a restriction on parental age of CHD onset, the association between carotid IMT and parental CHD was not statistically significant. There was also no significant association of common carotid IMT with premature or any parental CHD. CONCLUSIONS These findings suggest that subclinical atherosclerosis, assessed in the carotid arteries, is more prevalent in individuals with a family history of CHD. Early-onset parental CHD, in particular, identifies offspring with a strong familial predisposition to atherosclerosis.
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Abstract
BACKGROUND Atrial fibrillation (AF), the most common clinical arrhythmia, is a major cause of morbidity and mortality. Although AF is often associated with other cardiovascular conditions, many patients present without an obvious etiology. Inherited forms of AF exist, but the causative gene has been defined only in a single family. We have identified a large family (family FAF-1) in which AF segregates as a Mendelian trait. METHODS AND RESULTS Thirty-four family members were evaluated by 12-lead ECG, echocardiogram, 24-hour Holter monitoring, and laboratory studies. Individuals with electrocardiographically documented AF were defined as affected. Subjects were considered unaffected if they were >60 years of age, had no personal history of AF, and had no offspring with a history of AF. DNA was extracted and genotypic analyses were performed using polymorphic microsatellite markers. Evidence of linkage was obtained on chromosome 6, with a peak 2-point logarithm of the odds (LOD) score of 3.63 (theta=0) at the marker D6S1021. A maximal multipoint LOD score of 4.9 was obtained between D6S286 and D6S1021, indicating odds of approximately 100 000:1 in favor of this interval as the location of the gene defect responsible for AF in this family. The LOD scores were robust to changes in penetrance and allele frequency. Haplotype analyses further supported this minimal genetic interval. CONCLUSIONS We have mapped a novel locus for AF to chromosome 6q14-16. The identification of the causative gene in this interval will be an important step in understanding the fundamental mechanisms of AF.
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