Circulation. 2006;114:985
(Circulation. 2006;114:985.)
© 2006 American Heart Association, Inc.
Issue Highlights
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WILD-TYPE AND MUTANT HCN CHANNELS IN A TANDEM BIOLOGICAL-ELECTRONIC CARDIAC PACEMAKER, by Bucchi et al.
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and
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BIOARTIFICIAL SINUS NODE CONSTRUCTED VIA IN VIVO GENE TRANSFER OF AN ENGINEERED PACEMAKER HCN CHANNEL REDUCES THE DEPENDENCE ON ELECTRONIC PACEMAKER IN A SICK-SINUS SYNDROME MODEL, by Tse et al.
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Advances in technology have improved reliability of pacemaker
therapy for bradycardia due to sinus node dysfunction or complete
atrioventricular block. However, these electronic devices remain
imperfect and have finite battery longevity. Recent manufacturers’
advisories and US Food and Drug Administration recalls due to
component failures highlight the need for continued improvement.
In this issue of
Circulation, 2 separate studies by Bucchi and
colleagues and by Tse and colleagues report their findings of
experiments using bioengineered pacemaker channel technology.
Both groups found a decrease in electronic pacing when constructs
with engineered modified HCN channels were transfected into
cardiac tissue. Bucchi and colleagues demonstrated that a mutant
biological pacemaker implanted in a canine atrioventricular
block model conferred catecholamine-sensitive rate improvement
and less reliance on electronic pacemaker. Tse and colleagues
overexpressed a different mutant HCN channel in a porcine sinus
node dysfunction model, and similarly showed that transduction
in the atria induced spontaneous automaticity and a catecholamine-responsive
physiological heart rate that reduced electronic pacing. Although
not yet ready to render pacemakers obsolete, these studies further
our understanding of cardiac impulse generation and conduction.
These hybrid electronic-biological pacemaker systems illustrate
important advances in gene therapy for electrophysiological
abnormalities. See p 992 and p 1000 (editorial on p
986).
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SPECIFIC TEMPORAL PROFILE OF MATRIX METALLOPROTEINASE RELEASE OCCURS IN PATIENTS AFTER MYOCARDIAL INFARCTION: RELATION TO LEFT VENTRICULAR REMODELING, by Webb et al.
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Experimental studies in animals have shown that matrix metalloproteinases
(MMPs) and their endogenous inhibitors, the tissue inhibitors
of MMPs (TIMPs), play an important role in regulating myocardial
remodeling after myocardial infarction (MI). Webb et al measured
plasma levels of MMP-8 and -9 and TIMP-1, -2, and -4 sequentially
over the first 180 days after MI to characterize the temporal
pattern of MMP and TIMP in this clinical setting. A specific
MMP/TIMP temporal profile was found, with early increases in
MMP-8 and -9 and a later decrease in TIMP-4. These findings
raise the possibility that the MMP/TIMP profile can be used
as a biomarker and may yield diagnostic and prognostic information
in the post-MI period. See p
1020.
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DISTRIBUTION OF LIPOPROTEINS BY AGE AND GENDER IN ADOLESCENTS, by Jolliffe and Janssen
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Atherosclerosis can begin at a young age, and the rate of progression
is related to plasma lipoprotein concentrations. Lipoprotein
concentrations tend to persist from youth into adulthood, providing
further evidence that it is imperative to identify and manage
high-risk lipoprotein concentrations at an early age. The current
pediatric National Cholesterol Education Program (NCEP) classification
system does not recognize that lipoprotein concentrations fluctuate
naturally with growth and maturation. Jolliffe and Janssen have
devised an age-specific lipoprotein classification system for
adolescents. The adolescent thresholds, which were developed
using nationally representative data sets, were anchored to
the adult NCEP thresholds using growth curve modeling. These
adolescent lipoprotein classification systems are presented
in a series of growth curves and tables that are practical for
both clinical and research settings. It is hoped that the classification
systems developed in this study will better identify adolescents
with high-risk lipoprotein concentrations; validation studies
are needed, however. See p
1056.
Visit http://circ.ahajournals.org:
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Images in Cardiovascular Medicine
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Scimitar Syndrome: Complete Diagnosis by Transthoracic Echocardiography.
See p
e373.
Myocardial Fibroma in Gorlin Syndrome by Cardiac Magnetic Resonance Imaging. See p e376.
Large Pulmonary Artery Aneurysm Rupture in Hughes-Stovin Syndrome: Multidetector Computed Tomography Pattern and Endovascular Treatment. See p e380.
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Book Review
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Manual of Vascular Diseases. See p
e382.
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Correspondence
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See p
e383.
Related Articles:
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A Paradigm Shift in Cardiac Pacing Therapy?
- Douglas B. Cowan and Francis X. McGowan, Jr
Circulation 2006 114: 986-988.
[Full Text]
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Scimitar Syndrome: Complete Diagnosis by Transthoracic Echocardiography
- Rowlens M. Melduni, Farouk Mookadam, Martina Mookadam, Krishnaswamy Chandrasekaran, Fletcher A. Miller, Jae K. Oh, and A. Jamil Tajik
Circulation 2006 114: e373-e375.
[Full Text]
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Myocardial Fibroma in Gorlin Syndrome by Cardiac Magnetic Resonance Imaging
- Andrew T. Yan, Donna M. Coffey, Yi Li, Wing-Sze Chan, Adolphe J. Shayne, Tuan M. Luu, Ronald B. Skorstad, Maung M. Khin, Kenneth A. Brown, Martin J. Lipton, and Raymond Y. Kwong
Circulation 2006 114: e376-e379.
[Full Text]
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Large Pulmonary Artery Aneurysm Rupture in Hughes-Stovin Syndrome: Multidetector Computed Tomography Pattern and Endovascular Treatment
- Antoine Khalil, Antoine Parrot, Muriel Fartoukh, Claude Marsault, and Marie-France Carette
Circulation 2006 114: e380-e381.
[Full Text]
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Manual of Vascular Diseases
- Manu S. Rajachandran
Circulation 2006 114: e382.
[Full Text]
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Letter by Struthers et al Regarding Article, "Cross-Sectional Relations of Multiple Biomarkers From Distinct Biological Pathways to Brachial Artery Endothelial Function"
- Allan D. Struthers and Chim C. Lang
Circulation 2006 114: e383.
[Full Text]
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Specific Temporal Profile of Matrix Metalloproteinase Release Occurs in Patients After Myocardial Infarction: Relation to Left Ventricular Remodeling
- Carson S. Webb, David D. Bonnema, S. Hinan Ahmed, Amy H. Leonardi, Catherine D. McClure, Leslie L. Clark, Robert E. Stroud, William C. Corn, Laura Finklea, Michael R. Zile, and Francis G. Spinale
Circulation 2006 114: 1020-1027.
[Abstract]
[Full Text]
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Distribution of Lipoproteins by Age and Gender in Adolescents
- Courtney J. Jolliffe and Ian Janssen
Circulation 2006 114: 1056-1062.
[Abstract]
[Full Text]
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