Publications by authors named "Ernesto Salcedo"

57 Publications

Echocardiography-fluoroscopy fusion imaging: The essential features used in congenital and structural heart disease interventional guidance.

Echocardiography 2020 05 27;37(5):769-780. Epub 2020 Apr 27.

Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado.

Increased catheter-based interventions in congenital and structural heart disease require imaging modalities to be oriented in the same visual perspective. The use of echocardiography-fluoroscopy fusion (EFF) imaging has been developed for better characterization of complex anatomy and to facilitate key steps in interventional procedures. This review will detail the technology behind EFF, the differences between the two ultrasound fusion systems, and essential features of EFF imaging in congenital and structural heart disease interventions.
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http://dx.doi.org/10.1111/echo.14670DOI Listing
May 2020

Congenital and Structural Heart Disease Interventions Using Echocardiography-Fluoroscopy Fusion Imaging.

J Am Soc Echocardiogr 2019 12 6;32(12):1495-1504. Epub 2019 Oct 6.

Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado.

With the increasing frequency of catheter-based interventions in congenital heart disease and structural heart disease, the use of fusion imaging has become a major enhancement for understanding complex anatomy and facilitating key steps in interventional procedures. Because transesophageal echocardiography and fluoroscopy are displayed in different visual perspectives, the interventional cardiologist must mentally reregister the images from the two modalities during the procedure. Echocardiography-fluoroscopy fusion (EFF) imaging displays the x-ray and ultrasound overlay images in the same visual perspective. This new technology allows for enhanced team communication, improved visual guidance, and more efficient navigation. The purpose of this review is to describe the EFF imaging technology, current uses of EFF imaging in congenital and structural heart disease, and future directions that will enhance this unique imaging technology to guide interventional procedures.
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http://dx.doi.org/10.1016/j.echo.2019.07.023DOI Listing
December 2019

Three-dimensional reconstructions of mouse circumvallate taste buds using serial blockface scanning electron microscopy: I. Cell types and the apical region of the taste bud.

J Comp Neurol 2020 04 1;528(5):756-771. Epub 2019 Nov 1.

Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Denver, Colorado.

Taste buds comprise four types of taste cells: three mature, elongate types, Types I-III; and basally situated, immature postmitotic type, Type IV cells. We employed serial blockface scanning electron microscopy to delineate the characteristics and interrelationships of the taste cells in the circumvallate papillae of adult mice. Type I cells have an indented, elongate nucleus with invaginations, folded plasma membrane, and multiple apical microvilli in the taste pore. Type I microvilli may be either restricted to the bottom of the pore or extend outward reaching midway up into the taste pore. Type II cells (aka receptor cells) possess a large round or oval nucleus, a single apical microvillus extending through the taste pore, and specialized "atypical" mitochondria at functional points of contact with nerve fibers. Type III cells (aka "synaptic cells") are elongate with an indented nucleus, possess a single, apical microvillus extending through the taste pore, and are characterized by a small accumulation of synaptic vesicles at points of contact with nerve fibers. About one-quarter of Type III cells also exhibit an atypical mitochondrion near the presynaptic vesicle clusters at the synapse. Type IV cells (nonproliferative "basal cells") have a nucleus in the lower quarter of the taste bud and a foot process extending to the basement membrane often contacting nerve processes along the way. In murine circumvallate taste buds, Type I cells represent just over 50% of the population, whereas Types II, III, and IV (basal cells) represent 19, 15, and 14%, respectively.
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http://dx.doi.org/10.1002/cne.24779DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7041425PMC
April 2020

Differential Expression of Mucins in Murine Olfactory Versus Respiratory Epithelium.

Chem Senses 2019 09;44(7):511-521

Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, USA.

Mucins are a key component of the surface mucus overlying airway epithelium. Given the different functions of the olfactory and respiratory epithelia, we hypothesized that mucins would be differentially expressed between these 2 areas. Secondarily, we evaluated for potential changes in mucin expression with radiation exposure, given the clinical observations of nasal dryness, altered mucus rheology, and smell loss in radiated patients. Immunofluorescence staining was performed to evaluate expression of mucins 1, 2, 5AC, and 5B in nasal respiratory and olfactory epithelia of control mice and 1 week after exposure to 8 Gy of radiation. Mucins 1, 5AC, and 5B exhibited differential expression patterns between olfactory and respiratory epithelium (RE) while mucin 2 showed no difference. In the olfactory epithelium (OE), mucin 1 was located in a lattice-like pattern around gaps corresponding to dendritic knobs of olfactory sensory neurons, whereas in RE it was intermittently expressed by surface goblet cells. Mucin 5AC was expressed by subepithelial glands in both epithelial types but to a higher degree in the OE. Mucin 5B was expressed by submucosal glands in OE and by surface epithelial cells in RE. At 1-week after exposure to single-dose 8 Gy of radiation, no qualitative effects were seen on mucin expression. Our findings demonstrate that murine OE and RE express mucins differently, and characteristic patterns of mucins 1, 5AC, and 5B can be used to define the underlying epithelium. Radiation (8 Gy) does not appear to affect mucin expression at 1 week.

Level Of Evidence: N/A (Basic Science Research).IACUC-approved study [Protocol 200065].
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http://dx.doi.org/10.1093/chemse/bjz046DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357245PMC
September 2019

The acute effects of edge-to-edge percutaneous mitral valve repair on the shape and size of the mitral annulus and its relation to mitral regurgitation.

Echocardiography 2019 04 22;36(4):732-741. Epub 2019 Feb 22.

Division of Cardiology, University of Colorado Hospital, Anschutz Medical Center, University of Colorado School of Medicine, Aurora, Colorado.

Background: The effects of edge-to-edge percutaneous mitral valve repair on the shape and size of the mitral annulus and its relation to mitral regurgitation (MR) have not been well characterized. We evaluated acute changes in mitral annular shape and dimensions, and their effect on MR severity, in patients with functional and degenerative MR following MitraClip .

Methods: Patients that underwent MitraClip between January 2013 and May 2016 at our institution were retrospectively reviewed.

Exclusions: inadequate images, prior mitral valve repair, and rapid atrial fibrillation. Intra-procedure TEE 3D images acquired prior to and after implantation of MitraClip were analyzed using software to model the mitral valve apparatus.

Results: Of seventy-eight patients that underwent MitraClip procedure, 60 were eligible. Mean age was 78.3 ± 11 years. Severe MR (4+) was present in 37 patients, moderately/severe MR (3+) in 23. All patients achieved MR reduction to ≤2. 3D annular circumference, bicommissural diameter, and anteroposterior diameter had a significant size reduction after MitraClip . None of the mitral annular measures had significantly different mean change between the large and small MR change groups at the 0.05 significance level.

Conclusions: In patients with functional or degenerative MR, the MitraClip significantly affect mitral annular dimensions; however, these changes do not correlate with the immediate MR reduction.
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http://dx.doi.org/10.1111/echo.14284DOI Listing
April 2019

Echocardiography-Fluoroscopy Fusion Imaging for Guidance of Congenital and Structural Heart Disease Interventions.

JACC Cardiovasc Imaging 2019 07 16;12(7 Pt 1):1279-1282. Epub 2019 Jan 16.

Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado.

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http://dx.doi.org/10.1016/j.jcmg.2018.11.010DOI Listing
July 2019

Filamin C Truncation Mutations Are Associated With Arrhythmogenic Dilated Cardiomyopathy and Changes in the Cell-Cell Adhesion Structures.

JACC Clin Electrophysiol 2018 04 2;4(4):504-514. Epub 2018 Feb 2.

Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, Colorado. Electronic address:

Objectives: The purpose of this study was to assess the phenotype of Filamin C (FLNC) truncating variants in dilated cardiomyopathy (DCM) and understand the mechanism leading to an arrhythmogenic phenotype.

Background: Mutations in FLNC are known to lead to skeletal myopathies, which may have an associated cardiac component. Recently, the clinical spectrum of FLNC mutations has been recognized to include a cardiac-restricted presentation in the absence of skeletal muscle involvement.

Methods: A population of 319 U.S. and European DCM cardiomyopathy families was evaluated using whole-exome and targeted next-generation sequencing. FLNC truncation probands were identified and evaluated by clinical examination, histology, transmission electron microscopy, and immunohistochemistry.

Results: A total of 13 individuals in 7 families (2.2%) were found to harbor 6 different FLNC truncation variants (2 stopgain, 1 frameshift, and 3 splicing). Of the 13 FLNC truncation carriers, 11 (85%) had either ventricular arrhythmias or sudden cardiac death, and 5 (38%) presented with evidence of right ventricular dilation. Pathology analysis of 2 explanted hearts from affected FLNC truncation carriers showed interstitial fibrosis in the right ventricle and epicardial fibrofatty infiltration in the left ventricle. Ultrastructural findings included occasional disarray of Z-discs within the sarcomere. Immunohistochemistry showed normal plakoglobin signal at cell-cell junctions, but decreased signals for desmoplakin and synapse-associated protein 97 in the myocardium and buccal mucosa.

Conclusions: We found FLNC truncating variants, present in 2.2% of DCM families, to be associated with a cardiac-restricted arrhythmogenic DCM phenotype characterized by a high risk of life-threatening ventricular arrhythmias and a pathological cellular phenotype partially overlapping with arrhythmogenic right ventricular cardiomyopathy.
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http://dx.doi.org/10.1016/j.jacep.2017.12.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6074050PMC
April 2018

Endogenous Sex Steroids Dampen Neuroinflammation and Improve Outcome of Traumatic Brain Injury in Mice.

J Mol Neurosci 2018 Mar 15;64(3):410-420. Epub 2018 Feb 15.

Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave, Aurora, CO, 80045, USA.

The role of biological sex in short-term and long-term outcome after traumatic brain injury (TBI) remains controversial. The observation that exogenous female sex steroids (progesterone and estrogen) reduce brain injury coupled with a small number of clinical studies showing smaller injury in women suggest that sex steroids may play a role in outcome from TBI. We used the controlled cortical impact (CCI) model of TBI in mice to test the hypothesis that after CCI, female mice would demonstrate less injury than male mice, related to the protective role of endogenous steroids. Indeed, adult females exhibit histological protection (3.7 ± 0.5 mm) compared to adult male mice (6.8 ± 0.6 mm), and females that lacked sex steroids (ovex) showed increased injury compared to intact females. Consistent with histology, sensorimotor deficits measured as reduced contralateral limb use were most pronounced in male mice (31.9 ± 6.9% reduced limb use) compared to a 12.7 ± 3.8% reduction in female mice. Ovex mice exhibited behavioral deficits similar to males (31.5 ± 3.9% reduced limb use). Ovex females demonstrated increased microglial activation relative to intact females in both the peri-injury cortex and the reticular thalamic nucleus. Ovex females also demonstrated increased astrogliosis in comparison to both females and males in the peri-injury cortex. These data indicate that female sex steroids reduce brain sensitivity to TBI and that reduced acute neuroinflammation may contribute to the relative protection observed in females.
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http://dx.doi.org/10.1007/s12031-018-1038-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7374766PMC
March 2018

β-catenin is required for taste bud cell renewal and behavioral taste perception in adult mice.

PLoS Genet 2017 Aug 28;13(8):e1006990. Epub 2017 Aug 28.

Department of Cell & Developmental Biology and the Rocky Mountain Taste & Smell Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America.

Taste stimuli are transduced by taste buds and transmitted to the brain via afferent gustatory fibers. Renewal of taste receptor cells from actively dividing progenitors is finely tuned to maintain taste sensitivity throughout life. We show that conditional β-catenin deletion in mouse taste progenitors leads to rapid depletion of progenitors and Shh+ precursors, which in turn causes taste bud loss, followed by loss of gustatory nerve fibers. In addition, our data suggest LEF1, TCF7 and Wnt3 are involved in a Wnt pathway regulatory feedback loop that controls taste cell renewal in the circumvallate papilla epithelium. Unexpectedly, taste bud decline is greater in the anterior tongue and palate than in the posterior tongue. Mutant mice with this regional pattern of taste bud loss were unable to discern sweet at any concentration, but could distinguish bitter stimuli, albeit with reduced sensitivity. Our findings are consistent with published reports wherein anterior taste buds have higher sweet sensitivity while posterior taste buds are better tuned to bitter, and suggest β-catenin plays a greater role in renewal of anterior versus posterior taste buds.
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http://dx.doi.org/10.1371/journal.pgen.1006990DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5591015PMC
August 2017

Tonotopic alterations in inhibitory input to the medial nucleus of the trapezoid body in a mouse model of Fragile X syndrome.

J Comp Neurol 2017 Nov 15;525(16):3543-3562. Epub 2017 Aug 15.

Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado.

Hyperexcitability and the imbalance of excitation/inhibition are one of the leading causes of abnormal sensory processing in Fragile X syndrome (FXS). The precise timing and distribution of excitation and inhibition is crucial for auditory processing at the level of the auditory brainstem, which is responsible for sound localization ability. Sound localization is one of the sensory abilities disrupted by loss of the Fragile X Mental Retardation 1 (Fmr1) gene. Using triple immunofluorescence staining we tested whether there were alterations in the number and size of presynaptic structures for the three primary neurotransmitters (glutamate, glycine, and GABA) in the auditory brainstem of Fmr1 knockout mice. We found decreases in either glycinergic or GABAergic inhibition to the medial nucleus of the trapezoid body (MNTB) specific to the tonotopic location within the nucleus. MNTB is one of the primary inhibitory nuclei in the auditory brainstem and participates in the sound localization process with fast and well-timed inhibition. Thus, a decrease in inhibitory afferents to MNTB neurons should lead to greater inhibitory output to the projections from this nucleus. In contrast, we did not see any other significant alterations in balance of excitation/inhibition in any of the other auditory brainstem nuclei measured, suggesting that the alterations observed in the MNTB are both nucleus and frequency specific. We furthermore show that glycinergic inhibition may be an important contributor to imbalances in excitation and inhibition in FXS and that the auditory brainstem is a useful circuit for testing these imbalances.
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http://dx.doi.org/10.1002/cne.24290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615817PMC
November 2017

Sonic hedgehog from both nerves and epithelium is a key trophic factor for taste bud maintenance.

Development 2017 09 25;144(17):3054-3065. Epub 2017 Jul 25.

Department of Cell and Developmental Biology and the Rocky Mountain Taste and Smell Center University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA

The integrity of taste buds is intimately dependent on an intact gustatory innervation, yet the molecular nature of this dependency is unknown. Here, we show that differentiation of new taste bud cells, but not progenitor proliferation, is interrupted in mice treated with a hedgehog (Hh) pathway inhibitor (HPI), and that gustatory nerves are a source of sonic hedgehog (Shh) for taste bud renewal. Additionally, epithelial taste precursor cells express Shh transiently, and provide a local supply of Hh ligand that supports taste cell renewal. Taste buds are minimally affected when Shh is lost from either tissue source. However, when both the epithelial and neural supply of Shh are removed, taste buds largely disappear. We conclude Shh supplied by taste nerves and local taste epithelium act in concert to support continued taste bud differentiation. However, although neurally derived Shh is in part responsible for the dependence of taste cell renewal on gustatory innervation, neurotrophic support of taste buds likely involves a complex set of factors.
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http://dx.doi.org/10.1242/dev.150342DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5611957PMC
September 2017

Loss of Causes Slow, Progressive Retinal Degeneration in a Mouse Model of Familial Dysautonomia.

eNeuro 2016 Sep-Oct;3(5). Epub 2016 Sep 27.

Department of Cell Biology and Neuroscience, Montana State University , Bozeman, MT 59717.

Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein (). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for in the developing and adult retina, we generated conditional knockout (CKO) mice using a promoter-Cre (). In the retina, expression is detected predominantly in retinal ganglion cells (RGCs). At 6 months, significant loss of RGCs had occurred in the CKO retinas, with the greatest loss in the temporal retina, which is the same spatial phenotype observed in FD, Leber hereditary optic neuropathy, and dominant optic atrophy. Interestingly, the melanopsin-positive RGCs were resistant to degeneration. By 9 months, signs of photoreceptor degeneration were observed, which later progressed to panretinal degeneration, including RGC and photoreceptor loss, optic nerve thinning, Müller glial activation, and disruption of layers. Taking these results together, we conclude that although is not required for normal development of RGCs, its loss causes a slow, progressive RGC degeneration most severely in the temporal retina, which is later followed by indirect photoreceptor loss and complete retinal disorganization. This mouse model of FD is not only useful for identifying the mechanisms mediating retinal degeneration, but also provides a model system in which to attempt to test therapeutics that may mitigate the loss of vision in FD patients.
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http://dx.doi.org/10.1523/ENEURO.0143-16.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5037323PMC
October 2017

Super-resolution imaging of ciliary microdomains in isolated olfactory sensory neurons using a custom two-color stimulated emission depletion microscope.

J Biomed Opt 2016 06;21(6):66017

University of Colorado Denver Anschutz Medical Campus, Department of Bioengineering, MS 8607, 12700 East 19th Avenue, Aurora, Colorado 80045-2560, United States.

We performed stimulated emission depletion (STED) imaging of isolated olfactory sensory neurons (OSNs) using a custom-built microscope. The STED microscope uses a single pulsed laser to excite two separate fluorophores, Atto 590 and Atto 647N. A gated timing circuit combined with temporal interleaving of the different color excitation/STED laser pulses filters the two channel detection and greatly minimizes crosstalk. We quantified the instrument resolution to be ∼81 and ∼44  nm, for the Atto 590 and Atto 647N channels. The spatial separation between the two channels was measured to be under 10 nm, well below the resolution limit. The custom-STED microscope is incorporated onto a commercial research microscope allowing brightfield, differential interference contrast, and epifluorescence imaging on the same field of view. We performed immunolabeling of OSNs in mice to image localization of ciliary membrane proteins involved in olfactory transduction. We imaged Ca2+-permeable cyclic nucleotide gated (CNG) channel (Atto 594) and adenylyl cyclase type III (ACIII) (Atto 647N) in distinct cilia. STED imaging resolved well-separated subdiffraction limited clusters for each protein. We quantified the size of each cluster to have a mean value of 88±48  nm and 124±43  nm, for CNG and ACIII, respectively. STED imaging showed separated clusters that were not resolvable in confocal images.
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http://dx.doi.org/10.1117/1.JBO.21.6.066017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4923803PMC
June 2016

Incidence of Atrial Fibrillation following Alcohol Septal Ablation for Hypertrophic Cardiomyopathy.

Ann Noninvasive Electrocardiol 2016 Sep 11;21(5):443-9. Epub 2016 Mar 11.

Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO.

Background: Patients with hypertrophic cardiomyopathy (HCM) are at a fourfold to sixfold higher risk of developing atrial fibrillation (AF) compared to the general population, though incidence rates among patients undergoing alcohol septal ablation (ASA) are not well characterized. The purpose of this study was to evaluate atrial fibrillation incidence following ASA.

Methods: We studied 132 consecutive HCM patients without comorbid AF that underwent 154 ASA procedures. The incidence of AF in follow-up was assessed through chart abstraction including electrocardiography. Survival free of AF was estimated using Kaplan-Meier methodology.

Results: Over a mean follow-up of 3.6 ± 2.7 years (maximum 11.3 years), 10 (7.6%) patients developed new-onset AF. Of those who developed AF, both resting and provoked left ventricular outflow tract (LVOT) gradients had improved significantly (difference -79.78 mm Hg, P ≤ 0.005). Severity of mitral regurgitation improved in 7 (70%) patients. Survival free of AF was estimated to be 99.1%, 93.7%, and 91.7% at 1, 3, and 5 years.

Conclusions: Despite relieving LVOT obstruction and improving mitral regurgitation severity via ASA, new-onset AF remained a common complication of hypertrophic cardiomyopathy.
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http://dx.doi.org/10.1111/anec.12335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6931872PMC
September 2016

Arrhythmogenic Phenotype in Dilated Cardiomyopathy: Natural History and Predictors of Life-Threatening Arrhythmias.

J Am Heart Assoc 2015 Oct 16;4(10):e002149. Epub 2015 Oct 16.

Cardiovascular Institute and Adult Medical Genetics, University of Colorado, Aurora, CO (A.S., S.L.G., D.S., E.E.S., M.G.T., L.M.).

Background: Patients with dilated cardiomyopathy (DCM) may present with ventricular arrhythmias early in the disease course, unrelated to the severity of left ventricular dysfunction. These patients may be classified as having an arrhythmogenic DCM (AR-DCM). We investigated the phenotype and natural history of patients with AR-DCM.

Methods And Results: Two hundred eighty-five patients with a recent diagnosis of DCM (median duration of the disease 1 month, range 0 to 7 months) and who had Holter monitoring at baseline were comprehensively evaluated and followed for 107 months (range 29 to 170 months). AR-DCM was defined by the presence of ≥1 of the following: unexplained syncope, rapid nonsustained ventricular tachycardia (≥5 beats, ≥150 bpm), ≥1000 premature ventricular contractions/24 hours, and ≥50 ventricular couplets/24 hours, in the absence of overt heart failure. The primary end points were sudden cardiac death (SCD), sustained ventricular tachycardia (SVT), or ventricular fibrillation (VF). The secondary end points were death from congestive heart failure or heart transplantation. Of the 285 patients, 109 (38.2%) met criteria for AR-DCM phenotype. AR-DCM subjects had a higher incidence of SCD/SVT/VF compared with non-AR-DCM patients (30.3% vs 17.6%, P=0.022), with no difference in the secondary end points. A family history of SCD/SVT/VF and the AR-DCM phenotype were statistically significant and cumulative predictors of SCD/SVT/VF.

Conclusions: One-third of DCM patients may have an arrhythmogenic phenotype associated with increased risk of arrhythmias during follow-up. A family history of ventricular arrhythmias in DCM predicts a poor prognosis and increased risk of SCD.
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http://dx.doi.org/10.1161/JAHA.115.002149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4845125PMC
October 2015

Cdon promotes neural crest migration by regulating N-cadherin localization.

Dev Biol 2015 Nov 6;407(2):289-99. Epub 2015 Aug 6.

Department of Craniofacial Biology, School of Dental Medicine, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA. Electronic address:

Neural crest cells (NCCs) are essential embryonic progenitor cells that are unique to vertebrates and form a remarkably complex and coordinated system of highly motile cells. Migration of NCCs occurs along specific pathways within the embryo in response to both environmental cues and cell-cell interactions within the neural crest population. Here, we demonstrate a novel role for the putative Sonic hedgehog (Shh) receptor and cell adhesion regulator, cdon, in zebrafish neural crest migration. cdon is expressed in developing premigratory NCCs but is downregulated once the cells become migratory. Knockdown of cdon results in aberrant migration of trunk NCCs: crestin positive cells can emigrate out of the neural tube but stall shortly after the initiation of migration. Live cell imaging analysis demonstrates reduced directedness of migration, increased velocity and mispositioned cell protrusions. In addition, transplantation analysis suggests that cdon is required cell-autonomously for directed NCC migration in the trunk. Interestingly, N-cadherin is mislocalized following cdon knockdown suggesting that the role of cdon in NCCs is to regulate N-cadherin localization. Our results reveal a novel role for cdon in zebrafish neural crest migration, and suggest a mechanism by which Cdon is required to localize N-cadherin to the cell membrane in migratory NCCs for directed migration.
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http://dx.doi.org/10.1016/j.ydbio.2015.07.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663112PMC
November 2015

Analysis of Conserved Glutamate and Aspartate Residues in Drosophila Rhodopsin 1 and Their Influence on Spectral Tuning.

J Biol Chem 2015 Sep 20;290(36):21951-61. Epub 2015 Jul 20.

From the Departments of Cell and Developmental Biology, Ophthalmology and Rocky Mountain Lions Eye Institute, University of Colorado, Anschutz Medical Campus, School of Medicine, Aurora, Colorado 80045

The molecular mechanisms that regulate invertebrate visual pigment absorption are poorly understood. Studies of amphioxus Go-opsin have demonstrated that Glu-181 functions as the counterion in this pigment. This finding has led to the proposal that Glu-181 may function as the counterion in other invertebrate visual pigments as well. Here we describe a series of mutagenesis experiments to test this hypothesis and to also test whether other conserved acidic amino acids in Drosophila Rhodopsin 1 (Rh1) may serve as the counterion of this visual pigment. Of the 5 Glu and Asp residues replaced by Gln or Asn in our experiments, none of the mutant pigments shift the absorption of Rh1 by more than 6 nm. In combination with prior studies, these results suggest that the counterion in Drosophila Rh1 may not be located at Glu-181 as in amphioxus, or at Glu-113 as in bovine rhodopsin. Conversely, the extremely low steady state levels of the E194Q mutant pigment (bovine opsin site Glu-181), and the rhabdomere degeneration observed in flies expressing this mutant demonstrate that a negatively charged residue at this position is essential for normal rhodopsin function in vivo. This work also raises the possibility that another residue or physiologic anion may compensate for the missing counterion in the E194Q mutant.
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http://dx.doi.org/10.1074/jbc.M115.677765DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4571949PMC
September 2015

Integrated 3D echo-x ray to optimize image guidance for structural heart intervention.

JACC Cardiovasc Imaging 2015 Mar;8(3):371-374

University of Colorado Hospital, University of Colorado, Denver, Aurora, Colorado. Electronic address:

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http://dx.doi.org/10.1016/j.jcmg.2014.06.024DOI Listing
March 2015

Incidence and predictors of late complete heart block after alcohol septal ablation treatment of hypertrophic obstructive cardiomyopathy.

J Interv Cardiol 2015 Feb;28(1):90-7

Cardiology Division, Denver Health, Denver, Colorado; University of Colorado School of Medicine, Aurora, Colorado.

Objectives: This study was designed to identify the incidence of late complete heart block (CHB) first identified at least 48 hours post alcohol septal ablation (ASA).

Background: Septal reduction with ASA is a therapeutic option for patients with symptomatic hypertrophic obstructive cardiomyopathy (HCM). CHB, resulting from the septal infarct, is a known complication with a reported incidence of 9-22%. The incidence of CHB more than 48 hours post-procedure is unknown.

Methods: Consecutive patients who underwent ASA were analyzed and clinical characteristics associated with late CHB were assessed. Late CHB was defined as first identification of CHB more than 48 hours after ASA.

Results: From 2002-2013, 145 subjects underwent 168 ASA procedures and were followed for a mean of 3.2 +/- 2.3 years. The incidence of late CHB was 8.9% (15/168 ASA procedures). Heart block occurred from 48 hours to 3-years post-procedure. In a multivariable model, patients with any CHB were more likely to have had multiple ASA procedures (OR 4.14; 95% CI: 1.24, 13.9; P < 0.05) and high resting and provoked left ventricular outflow tract (LVOT) gradient assessed by catheterization (OR per 10 mmHg gradient 1.14; 95% CI: 1.0, 1.20; P < 0.05). After multivariable adjustment, only a high provokable LVOT gradient remained an independent predictor of late CHB (OR per 10 mmHg gradient 1.14 [95% CI 1.02-1.29]).

Conclusions: Late CHB is a common complication of ASA for treatment of symptomatic HCM. Post-discharge electrocardiographic surveillance for atrioventricular conduction disease should be considered after ASA, especially for those with a high provokable LVOT gradient.
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http://dx.doi.org/10.1111/joic.12178DOI Listing
February 2015

Titin and desmosomal genes in the natural history of arrhythmogenic right ventricular cardiomyopathy.

J Med Genet 2014 Oct 25;51(10):669-76. Epub 2014 Aug 25.

Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA.

Background: Genotype-phenotype correlations are poorly characterised in arrhythmogenic right ventricular cardiomyopathy (ARVC). We investigated whether carriers of rare variants in desmosomal genes (DC) and titin gene (TTN) display different phenotypes and clinical outcomes compared with non-carriers (NT-ND).

Methods And Results: Thirty-nine ARVC families (173 subjects, 67 affected) with extensive follow-up (mean 9 years), prospectively enrolled in the International Familial Cardiomyopathy Registry since 1991, were screened for rare variants in TTN and desmosomal genes (DSP, PKP2, DSG2, DSC2). Multiple clinical and outcome variables were compared between three genetic groups (TTN, DC, NT-ND) to define genotype-phenotype associations. Of the 39 ARVC families, 13% (5/39) carried TTN rare variants (11 affected subjects), 13% (5/39) DC (8 affected), while 74% (29/39) were NT-ND (48 affected). When compared with NT-ND, DC had a higher prevalence of inverted T waves in V2-3 (75% vs 31%, p=0.004), while TTN had more supraventricular arrhythmias (46% vs 13%, p=0.013) and conduction disease (64% vs 6% p<0.001). When compared with the NT-ND group, the DC group experienced a worse prognosis (67% vs 11%, p=0.03) and exhibited a lower survival free from death or heart transplant (59% vs 95% at 30 years, and 31% vs 89% at 50 years, HR 9.66, p=0.006), while the TTN group showed an intermediate survival curve (HR 4.26, p=0.037).

Conclusions: TTN carriers display distinct phenotypic characteristics including a greater risk for supraventricular arrhythmias and conduction disease. Conversely, DC are characterised by negative T waves in anterior leads, severe prognosis, high mortality and morbidity.
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http://dx.doi.org/10.1136/jmedgenet-2014-102591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4465780PMC
October 2014

Multimodality 3-dimensional image integration for congenital cardiac catheterization.

Methodist Debakey Cardiovasc J 2014 Apr-Jun;10(2):68-76

University of Colorado, Aurora, Colorado.

Cardiac catheterization procedures for patients with congenital and structural heart disease are becoming more complex. New imaging strategies involving integration of 3-dimensional images from rotational angiography, magnetic resonance imaging (MRI), computerized tomography (CT), and transesophageal echocardiography (TEE) are employed to facilitate these procedures. We discuss the current use of these new 3D imaging technologies and their advantages and challenges when used to guide complex diagnostic and interventional catheterization procedures in patients with congenital heart disease.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4117323PMC
http://dx.doi.org/10.14797/mdcj-10-2-68DOI Listing
October 2015

Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium.

Development 2014 Aug 3;141(15):2993-3002. Epub 2014 Jul 3.

Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO 80045, USA Graduate Program in Cell Biology, Stem Cells and Development, University of Colorado School of Medicine, Aurora, CO 80045, USA

Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation.
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http://dx.doi.org/10.1242/dev.107631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4197660PMC
August 2014

Left ventricular systolic function following alcohol septal ablation for symptomatic hypertrophic cardiomyopathy.

Am J Cardiol 2014 Apr 31;113(8):1401-4. Epub 2014 Jan 31.

Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Cardiology Division, Denver Health Medical Center, Denver, Colorado. Electronic address:

Because alcohol septal ablation (ASA) for the treatment of symptomatic hypertrophic cardiomyopathy (HC) with left ventricular (LV) outflow tract (LVOT) obstruction results in a myocardial infarct of up to 10% of ventricular mass, LV systolic function could decline over time. We evaluated LV function during longitudinal follow-up in a cohort of patients who underwent ASA. We studied 145 consecutive patients with HC that underwent 167 ASA procedures from 2002 to 2011. Echocardiographic follow-up was available in 139 patients (96%). Echocardiographic indexes included LV ejection fraction (LVEF), mitral regurgitation severity, systolic anterior motion of the anterior mitral leaflet, and resting and provoked LVOT gradients. All patients had a baseline LVEF of >55%. LVEF was preserved in 97.1% of patients over a mean follow-up time of 3.1±2.3 years (maximum 9.7). Mild LV systolic dysfunction was observed (LVEF range 44% to 54%) in only 4 patients. Mitral regurgitation severity improved in 67% (n=112 of 138 with complete data). Resting LVOT gradient declined from a mean of 75 to 19 mm Hg (p<0.001), and provoked gradient declined from a mean of 101 to 33 mm Hg (p<0.001). New York Heart Association class improved from a mean of 2.9±0.4 to 1.3±0.5 (p<0.001). In conclusion, LV systolic function is only mildly reduced in a minority of patients after ASA for symptomatic HC; other echocardiographic and functional measures were significantly improved.
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http://dx.doi.org/10.1016/j.amjcard.2014.01.417DOI Listing
April 2014

Procedural guidance using advance imaging techniques for percutaneous edge-to-edge mitral valve repair.

Curr Cardiol Rep 2014 Feb;16(2):452

Division of Cardiology, University of Colorado Denver, Anschutz Medical Campus, Mail Stop B132, Leprino 532, 12401 E. 17th Ave., Aurora, CO, 80045, USA,

The complexity of structural heart disease interventions such as edge-to edge mitral valve repair requires integration of multiple highly technical imaging modalities. Real time imaging with 3-dimensional (3D) echocardiography is a relatively new technique that first, allows clear volumetric imaging of target structures such as the mitral valve for both pre-procedural diagnosis and planning in patients with degenerative or functional mitral valve regurgitation. Secondly it provides intra-procedural, real-time panoramic volumetric 3D view of structural heart disease targets that facilitates eye-hand coordination while manipulating devices within the heart. X-ray fluoroscopy and RT 3D TEE images are used in combination to display specific targets and movement of catheter based technologies in 3D space. This integration requires at least two different image display monitors and mentally fusing the individual datasets by the operator. Combined display technology such as this, allow rotation and orientation of both dataset perspectives necessary to define targets and guidance of structural disease device procedures. The inherently easy concept of direct visual feedback and eye-hand coordination allows safe and efficient completion of MitraClip procedures. This technology is now merged into a single structural heart disease guidance mode called EchoNavigator(TM) (Philips Medical Imaging Andover, MA). These advanced imaging techniques have revolutionized the field of structural heart disease interventions and this experience is exemplified by a cooperative imaging approach used for guidance of edge-to-edge mitral valve repair procedures.
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http://dx.doi.org/10.1007/s11886-013-0452-5DOI Listing
February 2014

Poor prognosis of rare sarcomeric gene variants in patients with dilated cardiomyopathy.

Clin Transl Sci 2013 Dec 3;6(6):424-8. Epub 2013 Oct 3.

Cardiovascular Institute and Adult Medical Genetics, University of Colorado, Aurora, Colorado, USA; Cardiovascular Department "Ospedali Riuniti,"and University of Trieste, Trieste, Italy.

Background: In dilated cardiomyopathy (DCM), the clinical and prognostic implications of rare variants in sarcomeric genes remain poorly understood. To address this question, we analyzed the outcome of rare sarcomeric gene variants in patients enrolled in our Familial Cardiomyopathy Registry.

Methods: DCM families harboring rare sarcomeric variants in MYH6, MYH7, MYBPC3, TNNT2, and TTN were identified. Genotype-phenotype association analysis was performed, and long-term survival-free from death or heart transplant was compared between carriers and noncarriers.

Results: We found 24 rare variants (3 in MYH6, 3 in MYH7, 3 in MYBPC3, 2 in TNNT2, and 13 in TTN) affecting 52 subjects in 25 families. The phenotypes of variant carriers were severe (3 sudden deaths, 6 heart failure deaths, 8 heart transplants, 2 ventricular fibrillations). There was no difference in the overall long-term survival between carriers and the 33 noncarriers (p = 0.322). However after 50 years of age, the combined endpoint of death or transplant was decreased in carriers as compared to noncarriers (p = 0.026).

Conclusions: Patients with DCM carrying rare variants in sarcomeric genes manifest a poorer prognosis as compared to noncarriers after the age of 50 years. These data further support the role of genetic testing in DCM for risk stratification.
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http://dx.doi.org/10.1111/cts.12116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865161PMC
December 2013

Complex metabolically demanding sensory processing in the olfactory system: implications for epilepsy.

Epilepsy Behav 2014 Sep 7;38:37-42. Epub 2013 Oct 7.

Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.

Although the olfactory system is not generally associated with seizures, sharp application of odor eliciting activity in a large number of olfactory sensory neurons (OSNs) has been shown to elicit seizures. This is most likely due to increased ictal activity in the anterior piriform cortex-an area of the olfactory system that has limited GABAergic interneuron inhibition of pyramidal output cell activity. Such hyperexcitability in a well-characterized and highly accessible system makes olfaction a potentially powerful model system to examine epileptogenesis.
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http://dx.doi.org/10.1016/j.yebeh.2013.08.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3979506PMC
September 2014

Implementation of real-time three-dimensional transesophageal echocardiography for mitral balloon valvuloplasty.

Catheter Cardiovasc Interv 2013 Nov 19;82(6):994-8. Epub 2013 Jul 19.

Department of Medicine, Division of Cardiology, University of Texas Health Sciences Center, San Antonio, Texas.

Background: Transthoracic (TTE) and intracardiac echocardiography (ICE) have both been established as modalities for imaging guidance in mitral balloon valvuloplasty (MBV). Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) improves depth resolution, characterization of pathology and visualization of interventional catheters and devices. Three-dimensional imaging should enhance catheter navigation but improvements in procedural outcomes are not easily quantified. Using time from transseptal puncture to balloon inflation, procedure time and radiation exposure as surrogates for improvements linked to image guidance, we describe our early experience in implementing RT3D-TEE during MBV, a prototypical left-sided structural intervention.

Methods: Using a dedicated interventional procedures database, we reviewed the clinical and procedural variables of 70 consecutive cases of MBV utilizing either RT3D-TEE or TTE combined with ICE from 12/2004 to 4/2009.

Results: The clinical characteristics of both groups were well matched and there was no difference in mean gradient reduction or complication rates. Fluoroscopy times (TTE/ICE 26.7 ± 5.6 min. vs. RT3D-TEE 23.3 ± 6 min. P = 0.02) and radiation dose-area product (TTE/ICE 216.2 ± 96.6 vs. RT3D-TEE 171.5 ± 63.9) were lower with the RT3D-TEE cohort. Time from 1st transseptal puncture attempt to 1st balloon inflation was found to be lower in the RT-3DTEE cohort (TTE/ICE 36 ± 8 min vs. 28 ± 8 min P <0.01) CONCLUSION: RT3D-TEE is associated with expedited transseptal puncture and balloon catheter navigation as reflected in the decreased transseptal to balloon time. RT3D-TEE is associated with less reliance on fluoroscopic navigation as compared to using TTE/ICE. This series demonstrates the feasibility and advantages of implementing RT3D-TEE for MBV.
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http://dx.doi.org/10.1002/ccd.25052DOI Listing
November 2013

A TAP1 null mutation leads to an enlarged olfactory bulb and supernumerary, ectopic olfactory glomeruli.

Open Biol 2013 May 22;3(5):130044. Epub 2013 May 22.

Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA.

Major histocompatibility class I (MHCI) molecules are well known for their immunological role in mediating tissue graft rejection. Recently, these molecules were discovered to be expressed in distinct neuronal subclasses, dispelling the long-held tenet that the uninjured brain is immune-privileged. Here, we show that MHCI molecules are expressed in the main olfactory bulb (MOB) of adult animals. Furthermore, we find that mice with diminished levels of MHCI expression have enlarged MOBs containing an increased number of small, morphologically abnormal and ectopically located P2 glomeruli. These findings suggest that MHCI molecules may play an important role in the proper formation of glomeruli in the bulb.
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http://dx.doi.org/10.1098/rsob.130044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3866874PMC
May 2013

A sinus venosus atrial septal defect is diagnosed by echocardiography with an unusual bubble study.

Echocardiography 2013 Jul 1;30(6):E182-3. Epub 2013 Apr 1.

Division of Cardiology, School of Medicine, University of Colorado Denver, Aurora, Colorado 80045, USA.

A 68-year-old man underwent echocardiogram with agitated saline for a presumed diagnosis of primary pulmonary hypertension. Surprisingly, the bubbles from the agitated saline enter the left heart before filling the right side, leading to a diagnosis of Eisenmeger's syndrome from a sinus venosus atrial septal defect. Because of high right-sided pressure, the bubbles preferentially travel from the superior vena cava through the defect to the right superior pulmonary vein and left atrium, rather than the right side. This diagnosis was later confirmed on cardiac MRI.
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http://dx.doi.org/10.1111/echo.12191DOI Listing
July 2013