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Beattie MJ, Sleeper LA, Lu M, Teele SA, Breitbart RE, Esch JJ, Salvin JW, Kapoor U, Oladunjoye O, Emani SM, Banka P. Factors associated with morbidity, mortality, and hemodynamic failure after biventricular conversion in borderline hypoplastic left hearts. J Thorac Cardiovasc Surg 2023; 166:933-942.e3. [PMID: 36803549 DOI: 10.1016/j.jtcvs.2023.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 01/09/2023] [Accepted: 01/17/2023] [Indexed: 01/25/2023]
Abstract
OBJECTIVE A subset of patients with borderline hypoplastic left heart may be candidates for single to biventricular conversion, but long-term morbidity and mortality persist. Prior studies have shown conflicting results regarding the association of preoperative diastolic dysfunction and outcome, and patient selection remains challenging. METHODS Patients with borderline hypoplastic left heart undergoing biventricular conversion from 2005 to 2017 were included. Cox regression identified preoperative factors associated with a composite outcome of time to mortality, heart transplant, takedown to single ventricle circulation, or hemodynamic failure (defined as left ventricular end-diastolic pressure >20 mm Hg, mean pulmonary artery pressure >35 mm Hg, or pulmonary vascular resistance >6 international Woods units). RESULTS Among 43 patients, 20 (46%) met the outcome, with a median time to outcome of 5.2 years. On univariate analysis, endocardial fibroelastosis, lower left ventricular end-diastolic volume/body surface area (when <50 mL/m2), lower left ventricular stroke volume/body surface area (when <32 mL/m2), and lower left:right ventricular stroke volume ratio (when <0.7) were associated with outcome; higher preoperative left ventricular end-diastolic pressure was not. Multivariable analysis demonstrated that endocardial fibroelastosis (hazard ratio, 5.1, 95% confidence interval, 1.5-22.7, P = .033) and left ventricular stroke volume/body surface area 28 mL/m2 or less (hazard ratio, 4.3, 95% confidence interval, 1.5-12.3, P = .006) were independently associated with a higher hazard of the outcome. Approximately all patients (86%) with endocardial fibroelastosis and left ventricular stroke volume/body surface area 28 mL/m2 or less met the outcome compared with 10% of those without endocardial fibroelastosis and with higher stroke volume/body surface area. CONCLUSIONS History of endocardial fibroelastosis and smaller left ventricular stroke volume/body surface area are independent factors associated with adverse outcomes among patients with borderline hypoplastic left heart undergoing biventricular conversion. Normal preoperative left ventricular end-diastolic pressure is insufficient to reassure against diastolic dysfunction after biventricular conversion.
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Affiliation(s)
- Meaghan J Beattie
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass.
| | - Lynn A Sleeper
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Minmin Lu
- Department of Cardiology, Boston Children's Hospital, Boston, Mass
| | - Sarah A Teele
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Roger E Breitbart
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Jesse J Esch
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Joshua W Salvin
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Urvi Kapoor
- Department of Cardiology, Boston Children's Hospital, Boston, Mass
| | - Olubunmi Oladunjoye
- Department of Cardiovascular Surgery, Boston Children's Hospital, Boston, Mass
| | - Sitaram M Emani
- Department of Cardiovascular Surgery, Boston Children's Hospital, Boston, Mass; Department of Surgery, Harvard Medical School, Boston, Mass
| | - Puja Banka
- Department of Cardiology, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
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Morell E, Miller MK, Lu M, Friedman KG, Breitbart RE, Reichman JR, McDermott J, Sleeper LA, Blume ED. Parent and Physician Understanding of Prognosis in Hospitalized Children With Advanced Heart Disease. J Am Heart Assoc 2021; 10:e018488. [PMID: 33442989 PMCID: PMC7955315 DOI: 10.1161/jaha.120.018488] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Background The unpredictable trajectory of pediatric advanced heart disease makes prognostication difficult for physicians and informed decision‐making challenging for families. This study evaluated parent and physician understanding of disease burden and prognosis in hospitalized children with advanced heart disease. Methods and Results A longitudinal survey study of parents and physicians caring for patients with advanced heart disease age 30 days to 19 years admitted for ≥7 days was performed over a 1‐year period (n=160 pairs). Percentage agreement and weighted kappa statistics were used to assess agreement. Median patient age was 1 year (interquartile range, 1–5), 39% had single‐ventricle lesions, and 37% were in the cardiac intensive care unit. Although 92% of parents reported understanding their child's prognosis “extremely well” or “well,” 28% of physicians thought parents understood the prognosis only “a little,” “somewhat,” or “not at all.” Better parent‐reported prognostic understanding was associated with greater preparedness for their child's medical problems (odds ratio, 4.7; 95% CI, 1.4–21.7, P=0.02). There was poor parent–physician agreement in assessing functional class, symptom burden, and likelihood of limitations in physical activity and learning/behavior; on average, parents were more optimistic. Many parents (47%) but few physicians (6%) expected the child to have normal life expectancy. Conclusions Parents and physicians caring for children with advanced heart disease differed in their perspectives regarding prognosis and disease burden. Physicians tended to underestimate the degree of parent‐reported symptom burden. Parents were less likely to expect limitations in physical activity, learning/behavior, and life expectancy. Combined interventions involving patient‐reported outcomes, parent education, and physician communication tools may be beneficial.
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Affiliation(s)
- Emily Morell
- Division of Cardiology Department of Pediatrics Children's Hospital Los Angeles Los Angeles CA
| | | | - Minmin Lu
- Department of Cardiology Boston Children's Hospital Boston MA
| | | | | | | | - Julie McDermott
- Department of Cardiology Boston Children's Hospital Boston MA
| | - Lynn A Sleeper
- Department of Cardiology Boston Children's Hospital Boston MA
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Abstract
Background Troponin levels are frequently obtained in pediatric patients, but the benefit remains unclear. Methods and Results This retrospective study included 1993 patients aged 0 to 21 years without history of cardiac disease in whom troponin levels were obtained during clinical evaluation of cardiac and noncardiac presentations. Troponin was elevated (≥0.1 ng/mL) in 182 patients (9%). A cardiac diagnosis was made in 109 (60%) of those with elevated troponin and in 208 (12%) of those without (P<0.001). The positive predictive value of elevated troponin for a cardiac diagnosis was 60% for the entire cohort and 85% for patients with a cardiac presentation. The negative predictive value of nonelevated troponin was 89% for the entire cohort and 96% in patients without a cardiac presentation. Serial testing did not improve these predictive values. However, among 404 patients with initially nonelevated levels who had serial measurements, subsequent elevation was found in 80 (20%), of whom 15 (19%) had a cardiac diagnosis. The optimal troponin cutoff value to differentiate cardiac from noncardiac diagnosis was higher in children aged <3 months (0.045 ng/mL) compared with those aged ≥3 months (0.005 ng/mL). Conclusions Troponin can be a useful adjunctive test in the evaluation of children when the differential diagnosis includes cardiac etiologies. Serial measurement was not helpful when troponin was elevated at presentation but may merit consideration when the initial level is not elevated and there is ongoing concern about cardiac involvement. Lower reference values may be appropriate when evaluating children in contrast to adults.
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Affiliation(s)
- Audrey Dionne
- Department of Cardiology Boston Children's Hospital Boston MA.,Department of Pediatrics Harvard Medical School Boston MA
| | - John N Kheir
- Department of Cardiology Boston Children's Hospital Boston MA.,Department of Pediatrics Harvard Medical School Boston MA
| | - Lynn A Sleeper
- Department of Cardiology Boston Children's Hospital Boston MA.,Department of Pediatrics Harvard Medical School Boston MA
| | - Jesse J Esch
- Department of Cardiology Boston Children's Hospital Boston MA.,Department of Pediatrics Harvard Medical School Boston MA
| | - Roger E Breitbart
- Department of Cardiology Boston Children's Hospital Boston MA.,Department of Pediatrics Harvard Medical School Boston MA
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Fiedler AG, Banka P, Zaleski K, Fahey MC, Breitbart RE, Fynn-Thompson F. Delayed Presentation of Traumatic Pericardial Rupture: Diagnostic and Surgical Considerations for Treatment. Heart Surg Forum 2018; 21:E254-E256. [PMID: 30084774 DOI: 10.1532/hsf.1977] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022]
Abstract
Traumatic pericardial rupture is a rare event with high mortality. We present the case of a 15-year-old boy who sustained thoracic and abdominal trauma secondary to motor vehicle collision, with a delayed diagnosis of traumatic pericardial rupture with cardiac herniation. Out of concern for torsion and hemodynamic collapse, surgical repair was advised. We have developed a novel surgical approach to this rare condition, utilizing a combination of thoracoscopic and open surgical techniques. The guiding principles of our repair include the utilization of fenestrated pieces of bovine pericardium to create a tension free repair, minimizing the likelihood of pericardial effusion, and returning the cardiac mass to normal anatomic position.
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Affiliation(s)
- Amy G Fiedler
- Division of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA
| | - Puja Banka
- Division of Cardiology, Boston Children’s Hospital, Boston, MA, USA
| | - Katherine Zaleski
- Division of Cardiac Anesthesiology, Boston Children’s Hospital, Boston, MA, USA
| | - Michael C Fahey
- Division of Pediatric Cardiology, University of Massachusetts, Worcester, MA, USA
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Atz AM, Zak V, Mahony L, Uzark K, D'agincourt N, Goldberg DJ, Williams RV, Breitbart RE, Colan SD, Burns KM, Margossian R, Henderson HT, Korsin R, Marino BS, Daniels K, McCrindle BW. Longitudinal Outcomes of Patients With Single Ventricle After the Fontan Procedure. J Am Coll Cardiol 2017; 69:2735-2744. [PMID: 28571639 DOI: 10.1016/j.jacc.2017.03.582] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/19/2017] [Accepted: 03/29/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Multicenter longitudinal objective data for survival into adulthood of patients who have undergone Fontan procedures are lacking. OBJECTIVES This study sought to describe transplant-free survival and explore relationships between laboratory measures of ventricular performance and functional status over time. METHODS Exercise testing, echocardiography, B-type natriuretic peptide, functional health assessment, and medical history abstraction were repeated 9.4 ± 0.4 years after the Fontan Cross-Sectional Study (Fontan 1) and compared with previous values. Cox regression analysis explored risk factors for interim death or cardiac transplantation. RESULTS From the original cohort of 546 subjects, 466 were contacted again, and 373 (80%) were enrolled at 21.2 ± 3.5 years of age. Among subjects with paired testing, the percent predicted maximum oxygen uptake decreased (69 ± 14% vs. 61 ± 16%; p < 0.001; n = 95), ejection fraction decreased (58 ± 11% vs. 55 ± 10%; p < 0.001; n = 259), and B-type natriuretic peptide increased (median [interquartile range] 13 [7 to 25] pg/mol vs. 18 [9 to 36] pg/mol; p < 0.001; n = 340). At latest follow-up, a lower Pediatric Quality of Life Inventory physical summary score was associated with poorer exercise performance (R2 adjusted = 0.20; p < 0.001; n = 274). Cumulative complications since the Fontan procedure included additional cardiac surgery (32%), catheter intervention (62%), arrhythmia treatment (32%), thrombosis (12%), and protein-losing enteropathy (8%). Since Fontan 1, 54 subjects (10%) have received a heart transplant (n = 23) or died without transplantation (n = 31). The interval risk of death or/cardiac transplantation was associated with poorer ventricular performance and functional health status assessed at Fontan 1, but it was not associated with ventricular morphology, the subject's age, or the type of Fontan connection. CONCLUSIONS Interim transplant-free survival over 12 years in this Fontan cohort was 90% and was independent of ventricular morphology. Exercise performance decreased and was associated with worse functional health status. Future interventions might focus on preserving exercise capacity. (Relationship Between Functional Health Status and Ventricular Performance After Fontan-Pediatric Heart Network; NCT00132782).
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Affiliation(s)
- Andrew M Atz
- Medical University of South Carolina, Charleston, South Carolina.
| | - Victor Zak
- New England Research Institutes, Watertown, Massachusetts
| | - Lynn Mahony
- University of Texas Southwestern Medical Center, Dallas, Texas
| | | | | | | | | | | | | | - Kristin M Burns
- National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | | | | | | | | | | | - Brian W McCrindle
- University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
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Homsy J, Zaidi S, Shen Y, Ware JS, Samocha KE, Karczewski KJ, DePalma SR, McKean D, Wakimoto H, Gorham J, Jin SC, Deanfield J, Giardini A, Porter GA, Kim R, Bilguvar K, López-Giráldez F, Tikhonova I, Mane S, Romano-Adesman A, Qi H, Vardarajan B, Ma L, Daly M, Roberts AE, Russell MW, Mital S, Newburger JW, Gaynor JW, Breitbart RE, Iossifov I, Ronemus M, Sanders SJ, Kaltman JR, Seidman JG, Brueckner M, Gelb BD, Goldmuntz E, Lifton RP, Seidman CE, Chung WK. De novo mutations in congenital heart disease with neurodevelopmental and other congenital anomalies. Science 2016; 350:1262-6. [PMID: 26785492 DOI: 10.1126/science.aac9396] [Citation(s) in RCA: 516] [Impact Index Per Article: 64.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Congenital heart disease (CHD) patients have an increased prevalence of extracardiac congenital anomalies (CAs) and risk of neurodevelopmental disabilities (NDDs). Exome sequencing of 1213 CHD parent-offspring trios identified an excess of protein-damaging de novo mutations, especially in genes highly expressed in the developing heart and brain. These mutations accounted for 20% of patients with CHD, NDD, and CA but only 2% of patients with isolated CHD. Mutations altered genes involved in morphogenesis, chromatin modification, and transcriptional regulation, including multiple mutations in RBFOX2, a regulator of mRNA splicing. Genes mutated in other cohorts examined for NDD were enriched in CHD cases, particularly those with coexisting NDD. These findings reveal shared genetic contributions to CHD, NDD, and CA and provide opportunities for improved prognostic assessment and early therapeutic intervention in CHD patients.
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Affiliation(s)
- Jason Homsy
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Samir Zaidi
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Yufeng Shen
- Departments of Systems Biology and Biomedical Informatics, Columbia University Medical Center, New York, NY, USA
| | - James S Ware
- Department of Genetics, Harvard Medical School, Boston, MA, USA. NIHR Cardiovascular Biomedical Research Unit at Royal Brompton & Harefield NHS Foundation and Trust and Imperial College London, London, UK. National Heart & Lung Institute, Imperial College London, London, UK
| | - Kaitlin E Samocha
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Analytical and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston MA, USA
| | - Konrad J Karczewski
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Analytical and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston MA, USA
| | - Steven R DePalma
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Howard Hughes Medical Institute, Harvard University, Boston, MA, USA
| | - David McKean
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Hiroko Wakimoto
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Josh Gorham
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Sheng Chih Jin
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - John Deanfield
- Department of Cardiology, University College London and Great Ormond Street Hospital, London, UK
| | - Alessandro Giardini
- Department of Cardiology, University College London and Great Ormond Street Hospital, London, UK
| | - George A Porter
- Department of Pediatrics, University of Rochester Medical Center, The School of Medicine and Dentistry, Rochester, NY, USA
| | - Richard Kim
- Section of Cardiothoracic Surgery, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
| | - Kaya Bilguvar
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. Yale Center for Genome Analysis, Yale University, New Haven, CT, USA
| | | | - Irina Tikhonova
- Yale Center for Genome Analysis, Yale University, New Haven, CT, USA
| | - Shrikant Mane
- Yale Center for Genome Analysis, Yale University, New Haven, CT, USA
| | - Angela Romano-Adesman
- Steven and Alexandra Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Hongjian Qi
- Departments of Systems Biology and Biomedical Informatics, Columbia University Medical Center, New York, NY, USA. Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA
| | - Badri Vardarajan
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Lijiang Ma
- Department of Pediatrics, Columbia University Medical Center, New York, NY, USA
| | - Mark Daly
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Analytical and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston MA, USA
| | - Amy E Roberts
- Department of Cardiology, Children's Hospital Boston, Boston, MA, USA
| | - Mark W Russell
- Division of Pediatric Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Seema Mital
- Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Jane W Newburger
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - J William Gaynor
- Department of Pediatric Cardiac Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Roger E Breitbart
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Ivan Iossifov
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Stephan J Sanders
- Department of Psychiatry, University of California San Francisco, San Francisco, CA, USA
| | - Jonathan R Kaltman
- Heart Development and Structural Diseases Branch, Division of Cardiovascular Sciences, NHLBI/NIH, Bethesda, MD, USA
| | | | - Martina Brueckner
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.
| | - Bruce D Gelb
- Mindich Child Health and Development Institute and Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Elizabeth Goldmuntz
- Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Division of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Howard Hughes Medical Institute, Harvard University, Boston, MA, USA. Cardiovascular Division, Brigham & Women's Hospital, Harvard University, Boston, MA, USA.
| | - Wendy K Chung
- Departments of Pediatrics and Medicine, Columbia University Medical Center, New York, NY, USA.
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Atz AM, Zak V, Mahony L, Uzark K, Shrader P, Gallagher D, Paridon SM, Williams RV, Breitbart RE, Colan SD, Kaltman JR, Margossian R, Pasquali SK, Allen K, Lai WW, Korsin R, Marino BS, Mirarchi N, McCrindle BW. Survival data and predictors of functional outcome an average of 15 years after the Fontan procedure: the pediatric heart network Fontan cohort. CONGENIT HEART DIS 2014; 10:E30-42. [PMID: 24934522 DOI: 10.1111/chd.12193] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Multicenter longitudinal outcome data for Fontan patients surviving into adulthood are lacking. The aim of this study was to better understand contemporary outcomes in Fontan survivors by collecting follow-up data in a previously well-characterized cohort. DESIGN Baseline data from the Fontan Cross-Sectional Study (Fontan 1) were previously obtained in 546 Fontan survivors aged 11.9 ± 3.4 years. We assessed current transplant-free survival status in all subjects 6.8 ± 0.4 years after the Fontan 1 study. Anatomic, clinical, and surgical data were collected along with socioeconomic status and access to health care. RESULTS Thirty subjects (5%) died or underwent transplantation since Fontan 1. Subjects with both an elevated (>21 pg/mL) brain natriuretic peptide and a low Child Health Questionnaire physical summary score (<44) measured at Fontan 1 were significantly more likely to die or undergo transplant than the remainder, with a hazard ratio of 6.2 (2.9-13.5). Among 516 Fontan survivors, 427 (83%) enrolled in this follow-up study (Fontan 2) at 18.4 ± 3.4 years of age. Although mean scores on functional health status questionnaires were lower than the general population, individual scores were within the normal range in 78% and 88% of subjects for the Child Health Questionnaire physical and psychosocial summary score, and 97% and 91% for the SF-36 physical and mental aggregate score, respectively. Since Fontan surgery, 119 (28%) had additional cardiac surgery; 55% of these (n = 66) in the interim between Fontan 1 and Fontan 2. A catheter intervention occurred in 242 (57%); 32% of these (n = 78) after Fontan 1. Arrhythmia requiring treatment developed in 118 (28%) after Fontan surgery; 58% of these (n = 68) since Fontan 1. CONCLUSIONS We found 95% interim transplant-free survival for Fontan survivors over an average of 7 years of follow-up. Continued longitudinal investigation into adulthood is necessary to better understand the determinants of long-term outcomes and to improve functional health status.
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Affiliation(s)
- Andrew M Atz
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA
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McCrindle BW, Zak V, Breitbart RE, Mahony L, Shrader P, Lai WW, Burns KM, Colan SD, Williams RV, Goldberg D, Hill KD, Khaikin S, Atz AM. The relationship of patient medical and laboratory characteristics to changes in functional health status in children and adolescents after the Fontan procedure. Pediatr Cardiol 2014; 35:632-40. [PMID: 24264999 PMCID: PMC3959245 DOI: 10.1007/s00246-013-0831-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 10/26/2013] [Indexed: 10/26/2022]
Abstract
Despite hypothesized concerns about deterioration beginning in adolescence, longitudinal data and associated factors regarding standardized assessment of physical functioning are not available for Fontan patients. Parents who participated in the Fontan Cross-Sectional Study completed the Child Health Questionnaire at 2 time points for 245 subjects ages 6-18 years. Associations between change in Physical Functioning Summary Score and baseline patient, medical, and laboratory characteristics (mean age 9.5 ± 1.7 years) and follow-up patient and medical characteristics (mean age 16.2 ± 1.6 years) were determined by regression analyses. During a mean of 6.7 ± 0.4 years, a small (not clinically important) but statistically significant decrease in score from 46.2 ± 11.7 to 44.5 ± 12.1 (p < 0.03) was noted. Subjects with higher baseline scores had a greater decrease in score (r = -0.48; p < 0.001). A multivariable model of patient and medical characteristics (R(2) = 0.11) showed that a greater decrease in score was significantly associated with interim development of asthma (n = 13; parameter estimate [PE] -6.6; p < 0.05) or other chronic respiratory, lung, or breathing problems (n = 13; PE -12.5; p < 0.001) and the presence of protein-losing enteropathy at any time (n = 12; PE -9.4; p = 0.006). Change in score was not significantly associated with baseline laboratory measures of exercise capacity and ventricular characteristics and function. Therefore, although physical functioning may be stable during adolescence for many Fontan patients, deterioration occurs in some in association with respiratory conditions and protein-losing enteropathy. Further longitudinal study is necessary to better understand the relationship between clinical morbidities and functional health status as these patients transition into adulthood.
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Affiliation(s)
| | - Victor Zak
- New England Research Institutes, Watertown, MA
| | | | - Lynn Mahony
- University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Wyman W. Lai
- Columbia University Medical Center, New York, NY
| | | | | | | | | | | | - Svetlana Khaikin
- University of Toronto, The Hospital for Sick Children, Toronto, Canada
| | - Andrew M. Atz
- Medical University of South Carolina, Charleston, SC
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9
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Wu FM, Opotowsky AR, Raza R, Harney S, Ukomadu C, Landzberg MJ, Valente AM, Breitbart RE, Singh MN, Gauvreau K, Jonas MM. Transient elastography may identify Fontan patients with unfavorable hemodynamics and advanced hepatic fibrosis. CONGENIT HEART DIS 2014; 9:438-47. [PMID: 24418160 DOI: 10.1111/chd.12159] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/02/2013] [Indexed: 01/12/2023]
Abstract
BACKGROUND Transient elastography (TE) offers a noninvasive correlate with the degree of hepatic fibrosis. However, factors other than fibrosis affect liver stiffness. We sought to determine whether hepatic congestion related to hemodynamics in Fontan circulation influences liver stiffness measurement (LSM) assessed by TE. METHODS We studied 45 subjects with Fontan circulation undergoing cardiac catheterization with or without simultaneous liver biopsy. Subjects underwent TE within 5 days before catheterization. Clinical history, hemodynamic and biopsy data, and hepatic biomarkers were collected. Five subjects who had previously undergone liver biopsy and TE were also included. RESULTS Median age was 13.1 years (range 2.4-57.8); median time since Fontan was 9.9 years (range 0.1-32.5). No subject had known hepatitis C. Mean LSM for the entire cohort was 21.4 ± 10.8 kPa. Univariate regression analysis using LSM as a continuous outcome variable shows significant correlations with age (R = 0.35, P = .01), time since Fontan (R = 0.41, P = .003), Fontan pressure (R = 0.31, P = .04), cardiac index (R = 0.33, P = .03), pulmonary vascular resistance (R = 0.34, P = .03), systemic arterial oxygen saturation (R = 0.31, P = .04), and platelet count (R = 0.29, P = .05). On multiple regression analysis, Fontan pressure (β = 0.901, P = .03) and cardiac index (β = 2.703, P = .02) were significant predictors of LSM with overall model R(2) = 0.206. Univariate analysis shows LSM to be associated with more severe centrilobular fibrosis (P = .05). CONCLUSIONS Higher LSM is associated with unfavorable Fontan hemodynamics and advanced centrilobular hepatic fibrosis. TE may be a useful tool for identifying Fontan patients who warrant invasive testing.
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Affiliation(s)
- Fred M Wu
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Mass, USA; Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA
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Zaidi S, Choi M, Wakimoto H, Ma L, Jiang J, Overton JD, Romano-Adesman A, Bjornson RD, Breitbart RE, Brown KK, Carriero NJ, Cheung YH, Deanfield J, DePalma S, Fakhro KA, Glessner J, Hakonarson H, Italia MJ, Kaltman JR, Kaski J, Kim R, Kline JK, Lee T, Leipzig J, Lopez A, Mane SM, Mitchell LE, Newburger JW, Parfenov M, Pe'er I, Porter G, Roberts AE, Sachidanandam R, Sanders SJ, Seiden HS, State MW, Subramanian S, Tikhonova IR, Wang W, Warburton D, White PS, Williams IA, Zhao H, Seidman JG, Brueckner M, Chung WK, Gelb BD, Goldmuntz E, Seidman CE, Lifton RP. De novo mutations in histone-modifying genes in congenital heart disease. Nature 2013; 498:220-3. [PMID: 23665959 PMCID: PMC3706629 DOI: 10.1038/nature12141] [Citation(s) in RCA: 636] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/02/2013] [Indexed: 11/24/2022]
Abstract
Congenital heart disease (CHD) is the most frequent birth defect, affecting 0.8% of live births. Many cases occur sporadically and impair reproductive fitness, suggesting a role for de novo mutations. Here we compare the incidence of de novo mutations in 362 severe CHD cases and 264 controls by analysing exome sequencing of parent-offspring trios. CHD cases show a significant excess of protein-altering de novo mutations in genes expressed in the developing heart, with an odds ratio of 7.5 for damaging (premature termination, frameshift, splice site) mutations. Similar odds ratios are seen across the main classes of severe CHD. We find a marked excess of de novo mutations in genes involved in the production, removal or reading of histone 3 lysine 4 (H3K4) methylation, or ubiquitination of H2BK120, which is required for H3K4 methylation. There are also two de novo mutations in SMAD2, which regulates H3K27 methylation in the embryonic left-right organizer. The combination of both activating (H3K4 methylation) and inactivating (H3K27 methylation) chromatin marks characterizes 'poised' promoters and enhancers, which regulate expression of key developmental genes. These findings implicate de novo point mutations in several hundreds of genes that collectively contribute to approximately 10% of severe CHD.
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Affiliation(s)
- Samir Zaidi
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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11
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Atz AM, Zak V, Breitbart RE, Colan SD, Pasquali SK, Hsu DT, Lu M, Mahony L, Paridon SM, Puchalski MD, Geva T, McCrindle BW. Factors associated with serum brain natriuretic peptide levels after the Fontan procedure. CONGENIT HEART DIS 2011; 6:313-21. [PMID: 21435188 DOI: 10.1111/j.1747-0803.2011.00496.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Although a useful marker of heart failure in adults, the utility of brain natriuretic peptide concentration (BNP) for children after the Fontan procedure is not well studied. DESIGN BNP was measured in 510 patients who were 6-18 years old in the Pediatric Heart Network Fontan cross-sectional study at a median of 8.2 years after Fontan. Patients underwent echocardiography, exercise testing, magnetic resonance imaging (MRI) and functional health status questionnaires. Associations of BNP with baseline patient characteristics, medical history and cross-sectional assessment were examined with multivariable linear regression analyses. RESULTS The distribution of BNP was highly skewed, median 13.0 pg/mL (interquartile range: 7.1, 25.9), and was normalized with logarithmic transformation (logBNP). Among medical history variables, logBNP was greater in females (P= .02) and older patients (P < .001). Presence of pre-Fontan systolic ventricular dysfunction, greater number of post-Fontan complications, and thrombosis after Fontan were independently associated with higher logBNP (R(2) = 0.16). Age-adjusted logBNP was significantly related to Fontan connection type (lower with extracardiac conduits, higher with atriopulmonary connection; P < .001). Lower physical functioning health status (R(2) = 0.05), lower chronotropic index during exercise (R(2) = 0.17), indices of diastolic dysfunction measured by echocardiography (R(2) = 0.15), and higher total ventricular mass on MRI (R(2) = 0.33) were related to higher logBNP. CONCLUSIONS Despite a markedly abnormal circulation, BNP was variable but within a normal range in the majority of Fontan patients in this large outpatient cohort. Higher BNP was associated with several markers of suboptimal outcome, although associations were weak. The routine use of BNP as an outpatient surveillance tool in asymptomatic Fontan patients is not warranted.
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Affiliation(s)
- Andrew M Atz
- Medical University of South Carolina, Charleston, SC 29425, USA.
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12
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Anderson PAW, Breitbart RE, McCrindle BW, Sleeper LA, Atz AM, Hsu DT, Lu M, Margossian R, Williams RV. The Fontan patient: inconsistencies in medication therapy across seven pediatric heart network centers. Pediatr Cardiol 2010; 31:1219-28. [PMID: 20938655 PMCID: PMC3050513 DOI: 10.1007/s00246-010-9807-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/19/2010] [Indexed: 11/25/2022]
Abstract
Patients who have undergone the Fontan procedure are at risk for thrombosis, ventricular dysfunction, and valve regurgitation, but data to guide the medical treatment and prevention of these adverse outcomes in this population are lacking. This analysis examined medication usage among Fontan patients by putative indication and by study center. The medical history and current medications of 546 Fontan subjects, ages 6-18 years, were assessed in a Pediatric Heart Network multicenter cross-sectional study. Cardiac imaging was performed within 3 months of enrollment. The majority of the subjects (64%) were taking two or more medications. Antithrombotics were taken by 86% of those with a history of stroke, thrombosis, or both and 67% of those without such a history (P = 0.01). Conversely, 14% of those with a history of stroke, thrombosis, or both were taking no antithrombotic. Angiotensin-converting enzyme inhibitor (ACEi) therapy was independently associated with moderate or severe atrioventricular valve regurgitation (P = 0.004), right ventricular morphology (P < 0.001), and shorter time since Fontan (P = 0.004) but not with ventricular systolic dysfunction. Glycoside therapy and diuretic therapy each was associated with older age at Fontan (P = 0.001 and P = 0.023, respectively) and a history of post-Fontan arrhythmia (P < 0.001 and P = 0.003, respectively) but not with ventricular systolic dysfunction. Medication use rates varied widely among the centers, even with controls for center differences in patient characteristics. Prospective therapeutic trials are needed to guide the medical treatment of Fontan patients.
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Affiliation(s)
| | - Roger E. Breitbart
- Department of Cardiology, Children’s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Brian W. McCrindle
- Department of Pediatrics, The Hospital for Sick Children, Toronto, ON, Canada
| | - Lynn A. Sleeper
- Center for Statistical Analysis and Research, New England Research Institutes, Watertown, MA, USA
| | - Andrew M. Atz
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA
| | - Daphne T. Hsu
- Department of Pediatrics, Children’s Hospital of New York, New York, NY, USA
| | - Minmin Lu
- Center for Statistical Analysis and Research, New England Research Institutes, Watertown, MA, USA
| | - Renee Margossian
- Department of Cardiology, Children’s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Richard V. Williams
- Department of Pediatrics, Primary Children’s Medical Center, Salt Lake City, UT, USA
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13
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McCrindle BW, Zak V, Sleeper LA, Paridon SM, Colan SD, Geva T, Mahony L, Li JS, Breitbart RE, Margossian R, Williams RV, Gersony WM, Atz AM. Laboratory measures of exercise capacity and ventricular characteristics and function are weakly associated with functional health status after Fontan procedure. Circulation 2009; 121:34-42. [PMID: 20026781 DOI: 10.1161/circulationaha.109.869396] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Patients after the Fontan procedure are at risk for suboptimal functional health status, and associations with laboratory measures are important for planning interventions and outcome measures for clinical trials. METHODS AND RESULTS Parents completed the generic Child Health Questionnaire for 511 Fontan Cross-Sectional Study patients 6 to 18 years of age (61% male). Associations of Child Health Questionnaire Physical and Psychosocial Functioning Summary Scores (FSS) with standardized measurements from prospective exercise testing, echocardiography, magnetic resonance imaging, and measurement of brain natriuretic peptide were determined by regression analyses. For exercise variables for maximal effort patients only, the final model showed that higher Physical FSS was associated only with higher maximum work rate, accounting for 9% of variation in Physical FSS. For echocardiography, lower Tei index (particularly for patients with extracardiac lateral tunnel connections), lower indexed end-systolic volume, and the absence of atrioventricular valve regurgitation for patients having Fontan procedure at age <2 years were associated with higher Physical FSS, accounting for 14% of variation in Physical FSS. For magnetic resonance imaging, ratio of lower mass to end-diastolic volume and midquartiles of indexed end-systolic volume (nonlinear) were associated with higher Physical FSS, accounting for 11% of variation. Lower brain natriuretic peptide was significantly but weakly associated with higher Physical FSS (1% of variation). Significant associations for Psychosocial FSS with laboratory measures were fewer and weaker than for Physical FSS. CONCLUSIONS In relatively healthy Fontan patients, laboratory measures account for a small proportion of the variation in functional health status and therefore may not be optimal surrogate end points for trials of therapeutic interventions.
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Affiliation(s)
- Brian W McCrindle
- Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G 1X8.
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14
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Greenway SC, Pereira AC, Lin JC, DePalma SR, Israel SJ, Mesquita SM, Ergul E, Conta JH, Korn JM, McCarroll SA, Gorham JM, Gabriel S, Altshuler DM, Quintanilla-Dieck MDL, Artunduaga MA, Eavey RD, Plenge RM, Shadick NA, Weinblatt ME, De Jager PL, Hafler DA, Breitbart RE, Seidman JG, Seidman CE. De novo copy number variants identify new genes and loci in isolated sporadic tetralogy of Fallot. Nat Genet 2009; 41:931-5. [PMID: 19597493 PMCID: PMC2747103 DOI: 10.1038/ng.415] [Citation(s) in RCA: 314] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 06/03/2009] [Indexed: 11/17/2022]
Abstract
Tetralogy of Fallot (TOF), the most common severe congenital heart malformation, occurs sporadically, without other anomaly, and from unknown cause in 70% of cases. A genome-wide survey of 114 TOF patients and their unaffected parents identified 11 de novo copy number variants (CNVs) that were absent or extremely rare (<0.1%) in 2,265 controls. A second, independent TOF cohort (n = 398) was then examined for additional CNVs at these loci. In 1% (5/512, p = 0.0002, OR = 22.3) of non-syndromic sporadic TOF cases we identified CNVs at chromosome 1q21.1. Recurrent CNVs were also identified at 3p25.1, 7p21.3 and 22q11.2. CNVs in a single TOF case occurred at six loci, two that encode known (NOTCH1, JAG1) disease genes. Our data predicts that at least 10% (4.5–15.5, 95% CI) of sporadic, non-syndromic TOF reflects de novo CNVs and implicates mutations within these loci as etiologic in other cases of TOF.
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Affiliation(s)
- Steven C Greenway
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
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15
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Anderson PAW, Sleeper LA, Mahony L, Colan SD, Atz AM, Breitbart RE, Gersony WM, Gallagher D, Geva T, Margossian R, McCrindle BW, Paridon S, Schwartz M, Stylianou M, Williams RV, Clark BJ. Contemporary outcomes after the Fontan procedure: a Pediatric Heart Network multicenter study. J Am Coll Cardiol 2008; 52:85-98. [PMID: 18598886 PMCID: PMC4385517 DOI: 10.1016/j.jacc.2008.01.074] [Citation(s) in RCA: 286] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 01/17/2008] [Accepted: 01/26/2008] [Indexed: 01/03/2023]
Abstract
OBJECTIVES We characterized a large cohort of children who had a Fontan procedure, with measures of functional health status, ventricular size and function, exercise capacity, heart rhythm, and brain natriuretic peptide (BNP). BACKGROUND The characteristics of contemporary Fontan survivors are not well described. METHODS We enrolled 546 children (age 6 to 18 years, mean 11.9 years) and compared them within pre-specified anatomic and procedure subgroups. History and outcome measures were obtained within a 3-month period. RESULTS Predominant ventricular morphology was 49% left ventricular (LV), 34% right ventricular (RV), and 19% mixed. Ejection fraction (EF) was normal for 73% of subjects; diastolic function grade was normal for 28%. Child Health Questionnaire mean summary scores were lower than for control subjects; however, over 80% of subjects were in the normal range. Brain natriuretic peptide concentration ranged from <4 to 652 pg/ml (median 13 pg/ml). Mean percent predicted peak O2 consumption was 65% and decreased with age. Ejection fraction and EF Z score were lowest, and semilunar and atrioventricular (AV) valve regurgitation were more prevalent in the RV subgroup. Older age at Fontan was associated with more severe AV valve regurgitation. Most outcomes were not associated with a superior cavopulmonary connection before Fontan. CONCLUSIONS Measures of ventricular systolic function and functional health status, although lower on average in the cohort compared with control subjects, were in the majority of subjects within 2 standard deviations of the mean for control subjects. Right ventricular morphology was associated with poorer ventricular and valvular function. Effective strategies to preserve ventricular and valvular function, particularly for patients with RV morphology, are needed.
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16
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Abstract
The objective of this study was to determine the contemporary etiologies, treatment, and outcomes of moderate and large pericardial effusions in pediatric patients. We reviewed pediatric patients with moderate or large effusions diagnosed at Children's Hospital Boston. Effusion size was determined in offline review of echocardiograms. One hundred sixteen patients with moderate or large pericardial effusions were identified. The age range was 1 day to 17.8 years (median 8.6). The size of the pericardial effusions ranged from 0.5 to 4.7 cm (median 2.1). Neoplastic disease was present in 39% of patients, collagen vascular disease in 9%, renal disease in 8%, bacterial infection in 3%, and human immunodeficiency virus (HIV) in 2%; 37% were idiopathic. Pericardial drainage procedures were performed in 47 patients (41%). Of these, 29 (63%) had recurrent effusions leading to repeat drainage in 12 (41%). Pericardial effusions resolved within 3 months in 83% of patients who underwent drainage and in 91% of patients who did not. In summary, pediatric pericardial effusions were rarely caused by bacterial infections in this study population and were more frequently idiopathic or associated with neoplastic disease. Pericardial effusions often reaccumulated after drainage. The majority of both drained and undrained effusions resolved within 3 months.
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Affiliation(s)
- B Kühn
- Department of Cardiology, Children's Hospital Boston, Enders 12, 300 Longwood Avenue, Boston, MA 02115, USA.
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17
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Gurley SB, Allred A, Le TH, Griffiths R, Mao L, Philip N, Haystead TA, Donoghue M, Breitbart RE, Acton SL, Rockman HA, Coffman TM. Altered blood pressure responses and normal cardiac phenotype in ACE2-null mice. J Clin Invest 2006; 116:2218-25. [PMID: 16878172 PMCID: PMC1518789 DOI: 10.1172/jci16980] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2002] [Accepted: 06/06/2006] [Indexed: 12/27/2022] Open
Abstract
The carboxypeptidase ACE2 is a homologue of angiotensin-converting enzyme (ACE). To clarify the physiological roles of ACE2, we generated mice with targeted disruption of the Ace2 gene. ACE2-deficient mice were viable, fertile, and lacked any gross structural abnormalities. We found normal cardiac dimensions and function in ACE2-deficient animals with mixed or inbred genetic backgrounds. On the C57BL/6 background, ACE2 deficiency was associated with a modest increase in blood pressure, whereas the absence of ACE2 had no effect on baseline blood pressures in 129/SvEv mice. After acute Ang II infusion, plasma concentrations of Ang II increased almost 3-fold higher in ACE2-deficient mice than in controls. In a model of Ang II-dependent hypertension, blood pressures were substantially higher in the ACE2-deficient mice than in WT. Severe hypertension in ACE2-deficient mice was associated with exaggerated accumulation of Ang II in the kidney, as determined by MALDI-TOF mass spectrometry. Although the absence of functional ACE2 causes enhanced susceptibility to Ang II-induced hypertension, we found no evidence for a role of ACE2 in the regulation of cardiac structure or function. Our data suggest that ACE2 is a functional component of the renin-angiotensin system, metabolizing Ang II and thereby contributing to regulation of blood pressure.
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Affiliation(s)
- Susan B. Gurley
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Alicia Allred
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Thu H. Le
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Robert Griffiths
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Lan Mao
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Nisha Philip
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Timothy A. Haystead
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Mary Donoghue
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Roger E. Breitbart
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Susan L. Acton
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Howard A. Rockman
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Thomas M. Coffman
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
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18
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Rodrigue-Way A, Burkhoff D, Geesaman BJ, Golden S, Xu J, Pollman MJ, Donoghue M, Jeyaseelan R, Houser S, Breitbart RE, Marks A, Acton S. Sarcomeric genes involved in reverse remodeling of the heart during left ventricular assist device support. J Heart Lung Transplant 2005; 24:73-80. [PMID: 15653383 DOI: 10.1016/j.healun.2003.10.016] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2003] [Revised: 10/15/2003] [Accepted: 10/15/2003] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Left ventricular assist devices (LVADs) implanted in patients with severe congestive heart failure (CHF) as a bridge to transplantation have been shown to reverse chamber enlargement, regress cellular hypertrophy, and increase contractility. The purpose of this study was to gain a better understanding of the molecular changes associated with increased contractility after LVAD support. METHODS We took tissue sections from the left ventricular apex of 12 patients with CHF who were undergoing LVAD insertion (pre-LVAD) and from the LV free wall of those same patients before transplantation (post-LVAD). To control for sample-site differences, we obtained samples from the same regions in 7 patients with CHF who were undergoing transplantation without LVAD support and in 4 non- failing donor hearts. Gene expression was then probed on a custom DNA array containing 2,700 cardiac-enriched cDNA clones. RESULTS Calcium-handling genes were up-regulated by LVAD support, as previously reported. Sarcomeric genes were the other principle class of genes up-regulated by LVAD support, consistent with a possible restoration of sarcomere structure in reverse ventricular remodeling. However, a decrease in the fibrous component of the myocardium, also potentially involved in reverse remodeling, was not evident at the level of gene transcription because fibroblast markers were either unchanged or up-regulated. The remaining regulated genes did not fall into any defined functional class. CONCLUSIONS Changes in the regulation of sarcomeric, calcium-handling, and fibroblast genes during LVAD support indicate a cardiac molecular adaptation to mechanical unloading. These molecular changes may play a role in the observed increase in contractile function during reverse remodeling.
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Affiliation(s)
- Clifford L Cua
- Department of Cardiology, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
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20
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Donoghue M, Wakimoto H, Maguire CT, Acton S, Hales P, Stagliano N, Fairchild-Huntress V, Xu J, Lorenz JN, Kadambi V, Berul CI, Breitbart RE. Heart block, ventricular tachycardia, and sudden death in ACE2 transgenic mice with downregulated connexins. J Mol Cell Cardiol 2003; 35:1043-53. [PMID: 12967627 DOI: 10.1016/s0022-2828(03)00177-9] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Angiotensin converting enzyme related carboxypeptidase (ACE2) is a recently discovered homolog of angiotensin converting enzyme with tissue-restricted expression, including heart, and the capacity to cleave angiotensin peptides. We tested the hypothesis that cardiac ACE2 activity contributes to features of ventricular remodeling associated with the renin-angiotensin system by generating transgenic mice with increased cardiac ACE2 expression. These animals had a high incidence of sudden death that correlated with transgene expression levels. Detailed electrophysiology revealed severe, progressive conduction and rhythm disturbances with sustained ventricular tachycardia and terminal ventricular fibrillation. The gap junction proteins connexin40 and connexin43 were downregulated in the transgenic hearts, indicating that ACE2-mediated gap junction remodeling may account for the observed electrophysiologic disturbances. Spontaneous downregulation of the ACE2 transgene in surviving older animals correlated with restoration of nearly normal conduction, rhythm, and connexin expression.
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Affiliation(s)
- Mary Donoghue
- Millennium Pharmaceuticals, Inc., Cambridge, MA, USA
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21
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Abstract
A series of molecular pathways have in common a significant role in the pathogenesis and progression of atherosclerosis and cancer. Shared mechanisms implicated for both diseases include oxidative stress and the cellular damage that results from it, toxic metabolites produced by cigarette smoking, and increased dietary fat intake. Atherosclerosis may begin when an injury or infection mutates or transforms a single arterial smooth muscle cell in the progenitor of a proliferative clone, similar to the most widely held carcinogenesis theory. Cell proliferation regulatory pathways have been associated with plaque progression, stenosis, and restenosis after angioplasty and with cancer progression. Alterations in cell adhesion molecules have been linked to plaque formation and thrombosis and to tumor invasion and metastasis. Altered expression of proteases associated with thrombolysis has been implicated in atherosclerotic plaque expansion and hemorrhage and in the invasion and metastasis of malignant neoplasms. Ligand-growth factor receptor interactions have been associated with early atherosclerotic lesions and with cancer development and spread. Nuclear transcription factors have been associated with progression of both diseases. Angiogenesis modulators have been linked to plaque expansion and restenosis of atherosclerotic lesions and to local and metastatic tumor expansion.
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Affiliation(s)
- J S Ross
- Albany Medical College, Department of Pathology and Laboratory Medicine, NY 12208, USA
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22
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Ross JS, Stagliano NE, Donovan MJ, Breitbart RE, Ginsburg GS. Atherosclerosis and cancer: common molecular pathways of disease development and progression. Ann N Y Acad Sci 2001; 947:271-92; discussion 292-3. [PMID: 11795276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Recently, a series of shared molecular pathways have emerged that have in common a significant role in the pathogenesis and progression of both atherosclerosis and cancer. Oxidative stress and the cellular damage that results from it have been implicated in a wide variety of disease processes including atherogenesis and neoplasia. Toxic metabolites produced by cigarette smoking and increased dietary fat intake are implicated in the pathogenesis of both diseases. It has been hypothesized that atherosclerosis may begin when an injury or infection mutates or transforms a single arterial smooth muscle cell in the progenitor of a proliferative clone similar to the most widely held theory of carcinogenesis. Cell proliferation regulatory pathways including genes involved in the GIS checkpoint (p53, pRb, p15, p16, and cyclins A, D, E, and cdk 2,4) have been associated with plaque progression, stenosis and restenosis after angioplasty as well as in cancer progression. Alterations in cell adhesion molecules (integrins, cadherin-catenins) have been linked to plaque formation and thrombosis as well as to tumor invasion and metastasis. Altered expression of proteases associated with thrombolysis has been implicated in atherosclerotic plaque expansion and hemorrhage and in the invasion and metastasis of malignancy. Ligand-growth factor receptor interactions (tyrosine kinases) have been associated with early atherosclerotic lesions as well as cancer development and spread. Nuclear transcription factors such as NFkappaB have been associated with progression of both diseases. Angiogenesis modulators have recently been linked to plaque expansion and restenosis of atherosclerotic lesions as well as local and metastatic tumor expansion. Common disease treatments, such as the use of growth factor inhibitors and radiation treatment, established anticancer treatments, were recently introduced into atherosclerosis therapeutic strategies to prevent restenosis after angioplasty and endarterectomy. In conclusion, a series of molecular pathways of disease development and progression common to atherosclerosis and cancer support that the world's two most common diseases are far more closely aligned than previously believed and that emerging anti-inflammatory and antiproliferative therapeutic strategies may ultimately be efficacious in both conditions.
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Affiliation(s)
- J S Ross
- Albany Medical College, Department of Pathology and Laboratory Medicine, New York 12208, USA.
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23
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Herman MP, Sukhova GK, Libby P, Gerdes N, Tang N, Horton DB, Kilbride M, Breitbart RE, Chun M, Schönbeck U. Expression of neutrophil collagenase (matrix metalloproteinase-8) in human atheroma: a novel collagenolytic pathway suggested by transcriptional profiling. Circulation 2001; 104:1899-904. [PMID: 11602491 DOI: 10.1161/hc4101.097419] [Citation(s) in RCA: 236] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Loss of interstitial collagen, particularly type I collagen, the major load-bearing molecule of atherosclerotic plaques, renders atheroma prone to rupture. Initiation of collagen breakdown requires interstitial collagenases, a matrix metalloproteinase (MMP) subfamily consisting of MMP-1, MMP-8, and MMP-13. Previous work demonstrated the overexpression of MMP-1 and MMP-13 in human atheroma. However, no study has yet evaluated the expression of MMP-8, known as "neutrophil collagenase," the enzyme that preferentially degrades type I collagen, because granulocytes do not localize in plaques. METHODS AND RESULTS Transcriptional profiling and reverse transcription-polymerase chain reaction analysis revealed inducible expression of MMP-8 transcripts in CD40 ligand-stimulated mononuclear phagocytes. Western blot analysis demonstrated that 3 atheroma-associated cell types, namely, endothelial cells, smooth muscle cells, and mononuclear phagocytes, expressed MMP-8 in vitro upon stimulation with proinflammatory cytokines such as interleukin-1beta, tumor necrosis factor-alpha, or CD40 ligand. MMP-8 protein elaborated from these atheroma-associated cell types migrated as 2 immunoreactive bands, corresponding to the molecular weights of the zymogen and the active molecule. Extracts from atherosclerotic, but not nondiseased arterial tissue, contained similar immunoreactive bands. Moreover, all 3 cell types expressed MMP-8 mRNA and protein in human atheroma in situ. Notably, MMP-8 colocalized with cleaved but not intact type I collagen within the shoulder region of the plaque, a frequent site of rupture. CONCLUSIONS These data point to MMP-8 as a previously unsuspected participant in collagen breakdown, an important determinant of the vulnerability of human atheroma.
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MESH Headings
- Aorta/enzymology
- Aorta/pathology
- Arteriosclerosis/enzymology
- Arteriosclerosis/pathology
- CD40 Ligand
- Carotid Arteries/enzymology
- Carotid Arteries/pathology
- Cells, Cultured
- Collagen/metabolism
- Cytokines/pharmacology
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/pathology
- Gene Expression Profiling
- Humans
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/enzymology
- Matrix Metalloproteinase 8/biosynthesis
- Matrix Metalloproteinase 8/genetics
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- Phagocytes/enzymology
- Phagocytes/pathology
- RNA, Messenger/biosynthesis
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- M P Herman
- Leducq Center for Cardiovascular Research, Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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24
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Donoghue M, Hsieh F, Baronas E, Godbout K, Gosselin M, Stagliano N, Donovan M, Woolf B, Robison K, Jeyaseelan R, Breitbart RE, Acton S. A novel angiotensin-converting enzyme-related carboxypeptidase (ACE2) converts angiotensin I to angiotensin 1-9. Circ Res 2000; 87:E1-9. [PMID: 10969042 DOI: 10.1161/01.res.87.5.e1] [Citation(s) in RCA: 2084] [Impact Index Per Article: 86.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ACE2, the first known human homologue of angiotensin-converting enzyme (ACE), was identified from 5' sequencing of a human heart failure ventricle cDNA library. ACE2 has an apparent signal peptide, a single metalloprotease active site, and a transmembrane domain. The metalloprotease catalytic domains of ACE2 and ACE are 42% identical, and comparison of the genomic structures indicates that the two genes arose through duplication. In contrast to the more ubiquitous ACE, ACE2 transcripts are found only in heart, kidney, and testis of 23 human tissues examined. Immunohistochemistry shows ACE2 protein predominantly in the endothelium of coronary and intrarenal vessels and in renal tubular epithelium. Active ACE2 enzyme is secreted from transfected cells by cleavage N-terminal to the transmembrane domain. Recombinant ACE2 hydrolyzes the carboxy terminal leucine from angiotensin I to generate angiotensin 1-9, which is converted to smaller angiotensin peptides by ACE in vitro and by cardiomyocytes in culture. ACE2 can also cleave des-Arg bradykinin and neurotensin but not bradykinin or 15 other vasoactive and hormonal peptides tested. ACE2 is not inhibited by lisinopril or captopril. The organ- and cell-specific expression of ACE2 and its unique cleavage of key vasoactive peptides suggest an essential role for ACE2 in the local renin-angiotensin system of the heart and kidney. The full text of this article is available at http://www. circresaha.org.
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Affiliation(s)
- M Donoghue
- Millennium Pharmaceuticals, Inc, Cambridge, MA 02139, USA
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25
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Angelo S, Lohr J, Lee KH, Ticho BS, Breitbart RE, Hill S, Yost HJ, Srivastava D. Conservation of sequence and expression of Xenopus and zebrafish dHAND during cardiac, branchial arch and lateral mesoderm development. Mech Dev 2000; 95:231-7. [PMID: 10906469 DOI: 10.1016/s0925-4773(00)00334-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
dHAND and eHAND are related basic helix-loop-helix transcription factors that are expressed in the cardiac mesoderm and in numerous neural crest-derived cell types in chick and mouse. To better understand the evolutionary development of overlapping expression and function of the HAND genes during embryogenesis, we cloned the zebrafish and Xenopus orthologues. Comparison of dHAND sequences in zebrafish, Xenopus, chick, mouse and human demonstrated conservation throughout the protein. Expression of dHAND in zebrafish was seen in the earliest precursors of all lateral mesoderm at early gastrulation stages. At neurula and later stages, dHAND expression was observed in lateral precardiac mesoderm, branchial arch neural crest derivatives and posterior lateral mesoderm. At looping heart stages, cardiac dHAND expression remained generalized with no apparent regionalization. Interestingly, no eHAND orthologue was found in zebrafish. In Xenopus, dHAND and eHAND were co-expressed in the cardiac mesoderm without the segmental restriction seen in mice. Xenopus dHAND and eHAND were also expressed bilaterally in the lateral mesoderm without any left-right asymmetry. Within the branchial arches, XdHAND was expressed in a broader domain than XeHAND, similar to their mouse counterparts. Together, these data demonstrate conservation of HAND structure and expression across species.
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Affiliation(s)
- S Angelo
- Department of Pediatrics, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75235-9148, USA
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26
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Park M, Lewis C, Turbay D, Chung A, Chen JN, Evans S, Breitbart RE, Fishman MC, Izumo S, Bodmer R. Differential rescue of visceral and cardiac defects in Drosophila by vertebrate tinman-related genes. Proc Natl Acad Sci U S A 1998; 95:9366-71. [PMID: 9689086 PMCID: PMC21344 DOI: 10.1073/pnas.95.16.9366] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
tinman, a mesodermal NK2-type homeobox gene, is absolutely required for the subdivision of the early Drosophila mesoderm and for the formation of the heart as well as the visceral muscle primordia. Several vertebrate relatives of tinman, many of which are predominately expressed in the very early cardiac progenitors (and pharyngeal endoderm), also seem to promote heart development. Here, we show that most of these vertebrate tinman-related genes can readily substitute for Drosophila tinman function in promoting visceral mesoderm-specific marker gene expression, but much less in promoting cardiac-specific gene expression indicative of heart development. In addition, another mesodermal NK2-type gene from Drosophila, bagpipe, which is normally only needed for visceral mesoderm but not heart development, cannot substitute for tinman at all. These data indicate that the functional equivalence of the tinman-related subclass of NK2-type genes (in activating markers of visceral mesoderm development in Drosophila) is specific to this subclass and distinct from other homeobox genes. Despite the apparent overall conservation of heart development between vertebrates and invertebrates, the differential rescue of visceral mesoderm versus heart development suggests that some of the molecular mechanisms of organ formation may have diverged during evolution.
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Affiliation(s)
- M Park
- Department of Biology, University of Michigan, 830 N. University, Ann Arbor, MI 48109-1048, USA
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27
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Affiliation(s)
- M C Fishman
- Cardiovascular Research Center, Massachusetts General Hospital-East, Harvard Medical School, Charlestown 02129, USA
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28
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Lee KH, Xu Q, Breitbart RE. A new tinman-related gene, nkx2.7, anticipates the expression of nkx2.5 and nkx2.3 in zebrafish heart and pharyngeal endoderm. Dev Biol 1996; 180:722-31. [PMID: 8954740 DOI: 10.1006/dbio.1996.0341] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Drosophila homeobox gene tinman and its vertebrate homologs Nkx-2.5 and Nkx-2.3 are critical determinants of cardiac development. We report here the identification of a new tinman-related gene, nkx2.7, as well as orthologs of Nkx-2.5 and Nkx-2.3 in the zebrafish. Analysis of their expression in the developing zebrafish embryo reveals that nkx2.7 transcripts are the first to appear in cardiac mesodermal and pharyngeal endodermal precursors of the anterior hypoblast, anticipating both temporally and spatially the later expression of nkx2.5 and nkx2.3 in these lineages. The preeminence of nkx2.7 in these embryonic lineages is consistent with a key role in cell fate determination, perhaps in part through the induction of nkx2.5 and nkx2.3. The findings provide the first molecular clues as to the spatial organization of endodermal and cardiac mesodermal precursors in the zebrafish hypoblast immediately following gastrulation. They suggest a coordinate role for these three tinman-related genes in the development of the heart and pharyngeal arches, and reinforce the paradigm of gene duplication and subspecialization between Drosophila and vertebrate species. The results provide a framework in which to analyze potential changes in tinman-related gene expression during abnormal zebrafish development.
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Affiliation(s)
- K H Lee
- Department of Cardiology, Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts, 02115, USA.
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29
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Abstract
The zebrafish is an important experimental system for vertebrate embryology, and is well suited to the molecular analysis of muscle development. Transcription factors, such as the MEF2s, regulate skeletal and cardiac muscle-specific genes during development. We report the identification of three zebrafish MEF2 genes which, like their mammalian counterparts, encode factors that function as DNA-binding transcriptional activators of muscle specific promoters. The pattern of MEF2 expression in zebrafish defines discrete cell populations in the developing somites and heart and has mechanistic implications for developmental regulation of the MEF2 genes, when compared with other species. Alteration of MEF2 expression in two mutants affecting somitogenesis provides insight into the control of muscle formation in the embryo.
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Affiliation(s)
- B S Ticho
- Department of Cardiology, Children's Hospital, Boston, MA 02115, USA
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30
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Chen H, Charlat O, Tartaglia LA, Woolf EA, Weng X, Ellis SJ, Lakey ND, Culpepper J, Moore KJ, Breitbart RE, Duyk GM, Tepper RI, Morgenstern JP. Evidence that the diabetes gene encodes the leptin receptor: identification of a mutation in the leptin receptor gene in db/db mice. Cell 1996; 84:491-5. [PMID: 8608603 DOI: 10.1016/s0092-8674(00)81294-5] [Citation(s) in RCA: 1537] [Impact Index Per Article: 54.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OB-R is a high affinity receptor for leptin, an important circulating signal for the regulation of body weight. We identified an alternatively spliced transcript that encodes a form of mouse OB-R with a long intracellular domain. db/db mice also produce this alternatively spliced transcript, but with a 106 nt insertion that prematurely terminates the intracellular domain. We further identified G --> T point mutation in the genomic OB-R sequence in db/db mice. This mutation generates a donor splice site that converts the 106 nt region to a novel exon retained in the OB-R transcript. We predict that the long intracellular domain form of OB-R is crucial for initiating intracellular signal transduction, and as a corollary, the inability to produce this form of OB-R leads to the severe obese phenotype found in db/db mice.
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Affiliation(s)
- H Chen
- Millennium Pharmaceuticals, Incorporated, Cambridge, Massachusetts 02139, USA
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31
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Breitbart RE, London B, Nguyen HT, Satler CA. Recent Advances in the Laboratory of Molecular and Cellular Cardiology. Ann Thorac Surg 1995. [DOI: 10.1016/s0003-4975(21)01184-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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32
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Breitbart RE, London B, Nguyen HT, Satler CA. Recent advances in the Laboratory of Molecular and Cellular Cardiology. Ann Thorac Surg 1995; 60:S509-12. [PMID: 8604921 DOI: 10.1016/0003-4975(95)00654-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This article highlights some of the research in cardiac molecular biology in progress in the Department of Cardiology at Children's Hospital. It provides a sampling of investigative approaches to key questions in cardiovascular development and function and, as such, is intended as an overview rather than a comprehensive treatment of these problems. The featured projects, encompassing four different "model" systems, include (1) genetic analysis of the mef2 gene required for fruit fly cardial cell differentiation, (2) cardiac-specific homeobox factors in zebrafish cardiovascular development, (3) mouse transgenic and gene knockout models of cardiac potassium ion channel function, and (4) mapping and identification of human gene mutations causing long QT syndrome.
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Affiliation(s)
- R E Breitbart
- Department of Cardiology, Children's Hospital, Boston, Massachusetts 02115, USA
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33
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Breitbart RE, Liang CS, Smoot LB, Laheru DA, Mahdavi V, Nadal-Ginard B. A fourth human MEF2 transcription factor, hMEF2D, is an early marker of the myogenic lineage. Development 1993; 118:1095-106. [PMID: 8269842 DOI: 10.1242/dev.118.4.1095] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The transition from multipotent mesodermal precursor to committed myoblast and its differentiation into a mature myocyte involve molecular events that enable the cell to activate muscle-specific genes. Among the participants in this process is the myocyte-specific enhancer factor 2 (MEF2) family of tissue-restricted transcription factors. These factors, which share a highly conserved DNA-binding domain including a MADS box, are essential for the expression of multiple muscle genes with cognate target MEF2 sites in cis. We report here a new human MEF2 factor, hMEF2D, which is unique among the members of this family in that it is present not only in myotubes but also in undifferentiated myoblasts, even before the appearance of myogenin. hMEF2D comprises several alternatively spliced products of a single gene, one of which is the human homolog of the Xenopus SRF-related factor SL-1. Like its relatives, cloned hMEF2D is capable of activating transcription via sequence-specific binding to the MEF2 site, recapitulating endogenous tissue-specific MEF2 activity. Indeed, while MEF2D mRNAs are ubiquitous, the protein is highly restricted to those cell types that contain this activity, implicating posttranscriptional mechanisms in the regulation of MEF2D expression. Alternative splicing may be important in this process: two alternative MEF2D domains, at least one of which is specifically included during myogenic differentiation, also correlate precisely with endogenous MEF2 activity. These findings provide compelling evidence that MEF2D is an integral link in the regulatory network for muscle gene expression. Its presence in undifferentiated myoblasts further suggests that it may be a mediator of commitment in the myogenic lineage.
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Affiliation(s)
- R E Breitbart
- Howard Hughes Medical Institute, Boston, Massachusetts
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34
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Leifer D, Krainc D, Yu YT, McDermott J, Breitbart RE, Heng J, Neve RL, Kosofsky B, Nadal-Ginard B, Lipton SA. MEF2C, a MADS/MEF2-family transcription factor expressed in a laminar distribution in cerebral cortex. Proc Natl Acad Sci U S A 1993; 90:1546-50. [PMID: 7679508 PMCID: PMC45911 DOI: 10.1073/pnas.90.4.1546] [Citation(s) in RCA: 178] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have cloned cDNA encoding a human transcription factor that belongs to the MEF2 (myocyte-specific enhancer-binding factor 2) subfamily of the MADS (MCM1-agamous-deficiens-serum response factor) gene family. This factor, which we have named MEF2C, binds specifically to the MEF2 element and activates transcription via this element. Specific isoforms of this factor are found exclusively in brain and are robustly expressed by neurons in cerebral cortex. In situ hybridization indicates that the factor is expressed preferentially in certain neuronal layers of cortex and that expression declines during postnatal development. The unusual pattern of expression in brain suggests that this transcription factor may be important in the development of cortical architecture.
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Affiliation(s)
- D Leifer
- Department of Neurology, Children's Hospital, Boston, MA
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35
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Yu YT, Breitbart RE, Smoot LB, Lee Y, Mahdavi V, Nadal-Ginard B. Human myocyte-specific enhancer factor 2 comprises a group of tissue-restricted MADS box transcription factors. Genes Dev 1992; 6:1783-98. [PMID: 1516833 DOI: 10.1101/gad.6.9.1783] [Citation(s) in RCA: 418] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The MEF2 site is an essential element of muscle enhancers and promoters that is bound by a nuclear activity found, so far, only in muscle and required for tissue-specific transcription. We have cloned a group of transcription factors from human muscle that are responsible for this activity: They are present in muscle-specific DNA-binding complexes, have a target sequence specificity identical to that of the endogenous activity, and are MEF2 site-dependent transcriptional activators. These MEF2 proteins comprise several alternatively spliced isoforms from one gene and a related factor encoded by a second gene. All share a conserved amino-terminal DNA-binding domain that includes the MADS homology. MEF2 transcripts are ubiquitous but accumulate preferentially in skeletal muscle, heart, and brain. Specific alternatively spliced isoforms are restricted to these tissues, correlating exactly with the presence of endogenous MEF2 activity. Furthermore, MEF2 protein is detected only in skeletal and cardiac muscle nuclei and not in myoblast and nonmuscle cells. Thus, post-transcriptional regulation is important in the generation of tissue-specific MEF2 activity. Cardiac and smooth, as well as skeletal, muscles contain functionally saturating levels of MEF2 trans-activating factors that are absent in nonmuscle cells. Moreover, MEF2 is induced in nonmuscle cells by MyoD; however, MEF2 alone is insufficient to produce the full muscle phenotype. Implications for the molecular mechanisms of myogenesis are considered.
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Affiliation(s)
- Y T Yu
- Howard Hughes Medical Institute, Children's Hospital, Boston, Massachusetts
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36
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Nadal-Ginard B, Smith CW, Patton JG, Breitbart RE. Alternative splicing is an efficient mechanism for the generation of protein diversity: contractile protein genes as a model system. Adv Enzyme Regul 1991; 31:261-86. [PMID: 1877390 DOI: 10.1016/0065-2571(91)90017-g] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Alternative splicing has emerged in recent years as a widespread device for regulating gene expression and generating protein diversity. Its analysis has provided some mechanistic understanding of this form of gene regulation and, in addition, has provided new insights into some fundamental aspects of splicing. This mode of regulation is particularly prevalent in muscle cells, where genes such as troponin T are able to generate up to 64 different isoforms from a single transcriptional unit. Alternative splicing has the potential to raise the coding capacity of the small multigene families that code for the contractile proteins so that several million structurally different sarcomeres can be generated. The mammalian alpha-tropomyosin gene has proved particularly useful for the analysis of the mechanisms involved in this type of regulation. In particular, the mutually exclusive splicing of exons 2 and 3 has provided answers about the processes involved in the three main regulatory steps: (a) establishment of mutually exclusive behavior; (b) the elements involved in setting up the default pattern of splicing, and (c) the switch from the default to the regulated splicing pattern in some cell types.
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Affiliation(s)
- B Nadal-Ginard
- Howard Hughes Medical Institute, Department of Cardiology, Children's Hospital, Boston, MA
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37
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Breitbart RE, Nadal-Ginard B. Developmentally induced, muscle-specific trans factors control the differential splicing of alternative and constitutive troponin T exons. Cell 1987; 49:793-803. [PMID: 3581171 DOI: 10.1016/0092-8674(87)90617-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Alternative RNA splicing is a ubiquitous process permitting single genes to encode multiple protein isoforms. Here we report experiments in which a gene construct, containing combinatorial Troponin T (TnT) exons that manifest an exceptional diversity of alternative splicing in vivo, has been transfected into muscle and nonmuscle cells. Analyses of the spliced RNAs show that the alternative TnT exons retain their capacity for differential splicing in the modified minigene context when introduced into a variety of nonmuscle and muscle cells. The patterns of alternative splicing differ depending on cell type. Only in differentiated myotubes are the alternative exons normally incorporated during splicing, reproducing their behavior in the native gene; they are excluded in nonmuscle cells and myoblasts that do not express the endogenous TnT. These results provide proof that trans factors required for correct alternative splicing are induced during myogenesis. Surprisingly, such factors are also required for the correct splicing of constitutive TnT exons.
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38
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Breitbart RE, Andreadis A, Nadal-Ginard B. Alternative splicing: a ubiquitous mechanism for the generation of multiple protein isoforms from single genes. Annu Rev Biochem 1987; 56:467-95. [PMID: 3304142 DOI: 10.1146/annurev.bi.56.070187.002343] [Citation(s) in RCA: 553] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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39
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Breitbart RE, Nadal-Ginard B. Complete nucleotide sequence of the fast skeletal troponin T gene. Alternatively spliced exons exhibit unusual interspecies divergence. J Mol Biol 1986; 188:313-24. [PMID: 3735424 DOI: 10.1016/0022-2836(86)90157-9] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The continuous nucleotide sequence of the rat fast skeletal muscle troponin T gene is reported, complementing the previous determinations of its structural organization and its capacity to encode multiple isoforms via alternative RNA splicing. Canonical promoter elements, as well as consensus sequences that may be involved in the 3' processing of the primary transcript, are present. All exons are flanked by conventional donor and acceptor splice sites, which can hybridize to U1 RNA. Extensive computer-assisted analyses of the genomic sequence do not reveal cis elements that unambiguously distinguish alternative from constitutive exons. Local RNA secondary structures can be predicted, however, that sequester exons or their splice sites in stem-and-loop formations, and which may also pair with small nuclear RNAs. These interactions might, in theory, contribute to differential exon usage. The structural features of exon organization that characterize this rat skeletal gene are closely conserved in the chicken cardiac troponin T gene, but the former exhibits a more diversified capacity for differential splicing. Implications for the mechanisms of alternative RNA splicing are considered. Comparisons of troponin T amino acid sequences among several species reveal striking dissimilarities, in contrast to the otherwise highly conserved contractile proteins. These divergences involve entire peptide subsegments and are concentrated in the same domains as are encoded by alternatively spliced exons, suggesting that exon shuffling may have contributed to the evolution of troponin T.
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40
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Breitbart RE, Nguyen HT, Medford RM, Destree AT, Mahdavi V, Nadal-Ginard B. Intricate combinatorial patterns of exon splicing generate multiple regulated troponin T isoforms from a single gene. Cell 1985; 41:67-82. [PMID: 2986851 DOI: 10.1016/0092-8674(85)90062-5] [Citation(s) in RCA: 266] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mechanisms of alternative RNA splicing, important in the generation of protein diversity, are common but incompletely understood. Among the contractile proteins, troponin T exists in several isoforms, shown to be derived in part from a novel pattern of differential RNA splicing in the 3' region of the rat skeletal fast troponin T gene. In fact, this gene has a previously unsuspected capacity to encode multiple isoforms. The isolation of four distinct but related cDNAs from this gene, which share discontinuous subsegments of sequence identity in their 5' regions, and the determination of the genomic sequence, demonstrate that small exons with characteristic split codon structure are differentially spliced in intricate combinatorial patterns to generate a minimum of 10, and potentially 64, distinct troponin T mRNAs, encoding different isoforms, in a developmentally regulated and tissue-specific manner. At least two of these mRNAs are spliced from structurally identical primary transcripts, necessitating control by trans-acting factors.
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