Publications by authors named "Elisabetta Lazzarini"

8 Publications

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Distinct molecular signature of phospholamban p.Arg14del arrhythmogenic cardiomyopathy.

Cardiovasc Pathol 2019 May - Jun;40:2-6. Epub 2018 Dec 21.

University of Groningen, University Medical Center Groningen, Department of Pathology, Groningen, The Netherlands.

Phospholamban (PLN) p.Arg14del cardiomyopathy is characterized by a distinct arrhythmogenic biventricular phenotype that can be predominantly left ventricular, right ventricular, or both. Our aim was to further elucidate distinct features of this cardiomyopathy with respect to the distribution of desmosomal proteins observed by immunofluorescence (IF) in comparison to desmosomal arrhythmogenic cardiomyopathy and co-existent genetic variants. We studied eight explanted heart specimens from PLN p.Arg14del mutation carriers. Macro- and microscopic examination revealed biventricular presence of fibrofatty replacement and interstitial fibrosis. Five out of 8 (63%) patients met consensus criteria for both arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM). In four cases, targeted next-generation sequencing revealed one additional pathogenic variant and six variants of unknown significance. IF showed diminished junction plakoglobin signal intensity at the intercalated disks in 4 (67%) out of 6 cases fulfilling ARVC criteria but normal intensity in both cases fulfilling only DCM criteria. Notably, the four cases with diminished junction plakoglobin were also those where an additional gene variant was detected. IF for two proteins recently investigated in desmosomal arrhythmogenic cardiomyopathy (ACM), synapse-associated protein 97 and glycogen synthase kinase-3 beta, showed a distinct distributional pattern in comparison to desmosomal ACM. In 7 (88%) out of 8 cases we observed both a strong synapse-associated protein 97 signal at the sarcomeres and no glycogen synthase kinase-3 beta translocation to the intercalated discs. Phospholamban p.Arg14del cardiomyopathy is characterized by a distinct molecular signature compared to desmosomal ACM, specifically a different desmosomal protein distribution. This study substantiates the idea that additional genetic variants play a role in the phenotypical heterogeneity.
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http://dx.doi.org/10.1016/j.carpath.2018.12.006DOI Listing
July 2019

Large Genomic Rearrangements of Desmosomal Genes in Italian Arrhythmogenic Cardiomyopathy Patients.

Circ Arrhythm Electrophysiol 2017 Oct;10(10)

From the Departments of Cardiac, Thoracic, and Vascular Sciences (K.P., E.L., I.R., R.C., M.P.M., M.C., S.R., S.I., L.D., D.C., G. T., C.B., B.B.) and Medicine (D.R.), University of Padua, Italy; Department of Biology, University of Padua, Italy (M.D.B., M.C., G.P., A.R., A.L., G.O.); University Medical Center Groningen, University of Groningen, The Netherlands (J.J.); Cardiology Division, Casa di Cura Pederzoli, Peschiera del Garda, Italy (P.D.); and Department of Clinical Genetics, University of Amsterdam, The Netherlands (J.P.V.T.).

Background: Arrhythmogenic cardiomyopathy (AC) is an inherited heart muscle disease associated with point mutations in genes encoding for cardiac desmosome proteins. Conventional mutation screening is positive in ≈50% of probands. Copy number variations (CNVs) have recently been linked to AC pointing to the need to determine the prevalence of CNVs in desmosomal genes and to evaluate disease penetrance by cosegregation analysis in family members.

Methods And Results: A total of 160 AC genotype-negative probands for 5 AC desmosomal genes by conventional mutation screening underwent multiplex ligation-dependent probe amplification. Nine heterozygous CNVs were identified in 11 (6.9%) of the 160 probands. Five carried a deletion of the entire plakophilin-2 () gene, 2 a deletion of only exon 4, 1 a deletion of the exons 6 to 11, 1 a duplication of 5' untranslated region till exon 1, 1 the desmocollin-2 () duplication of exons 7 to 9, and 1 a large deletion of chromosome 18 comprising both and genes. All probands were affected by moderate-severe forms of the disease, whereas 10 (32%) of the 31 family members carrying one of these deletions fulfilled the diagnostic criteria.

Conclusions: Genomic rearrangements were detected in ≈7% of AC probands negative for pathogenic point mutations in desmosomal genes, highlighting the potential of CNVs analysis to substantially increase the diagnostic yield of genetic testing. Genotype-phenotype correlation demonstrated the presence of the disease in about one third of family members carrying the CNV, underlying the role of other factors in the development and progression of the disease.
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http://dx.doi.org/10.1161/CIRCEP.117.005324DOI Listing
October 2017

Arrhythmogenic cardiomyopathy.

Orphanet J Rare Dis 2016 Apr 2;11:33. Epub 2016 Apr 2.

Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Padua, Italy.

Arrhythmogenic cardiomyopathy (AC) is a heart muscle disease clinically characterized by life-threatening ventricular arrhythmias and pathologically by an acquired and progressive dystrophy of the ventricular myocardium with fibro-fatty replacement. Due to an estimated prevalence of 1:2000-1:5000, AC is listed among rare diseases. A familial background consistent with an autosomal-dominant trait of inheritance is present in most of AC patients; recessive variants have also been reported, either or not associated with palmoplantar keratoderma and woolly hair. AC-causing genes mostly encode major components of the cardiac desmosome and up to 50% of AC probands harbor mutations in one of them. Mutations in non-desmosomal genes have been also described in a minority of AC patients, predisposing to the same or an overlapping disease phenotype. Compound/digenic heterozygosity was identified in up to 25% of AC-causing desmosomal gene mutation carriers, in part explaining the phenotypic variability. Abnormal trafficking of intercellular proteins to the intercalated discs of cardiomyocytes and Wnt/beta catenin and Hippo signaling pathways have been implicated in disease pathogenesis.AC is a major cause of sudden death in the young and in athletes. The clinical picture may include a sub-clinical phase; an overt electrical disorder; and right ventricular or biventricular pump failure. Ventricular fibrillation can occur at any stage. Genotype-phenotype correlation studies led to identify biventricular and dominant left ventricular variants, thus supporting the use of the broader term AC.Since there is no "gold standard" to reach the diagnosis of AC, multiple categories of diagnostic information have been combined and the criteria recently updated, to improve diagnostic sensitivity while maintaining specificity. Among diagnostic tools, contrast enhanced cardiac magnetic resonance is playing a major role in detecting left dominant forms of AC, even preceding morpho-functional abnormalities. The main differential diagnoses are idiopathic right ventricular outflow tract tachycardia, myocarditis, sarcoidosis, dilated cardiomyopathy, right ventricular infarction, congenital heart diseases with right ventricular overload and athlete heart. A positive genetic test in the affected AC proband allows early identification of asymptomatic carriers by cascade genetic screening of family members. Risk stratification remains a major clinical challenge and antiarrhythmic drugs, catheter ablation and implantable cardioverter defibrillator are the currently available therapeutic tools. Sport disqualification is life-saving, since effort is a major trigger not only of electrical instability but also of disease onset and progression. We review the current knowledge of this rare cardiomyopathy, suggesting a flowchart for primary care clinicians and geneticists.
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http://dx.doi.org/10.1186/s13023-016-0407-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818879PMC
April 2016

TGF-beta1 pathway activation and adherens junction molecular pattern in nonsyndromic mitral valve prolapse.

Cardiovasc Pathol 2015 Nov-Dec;24(6):359-67. Epub 2015 Aug 1.

Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Padua, Italy. Electronic address:

Aims: Dysregulation of the transforming growth factor beta (TGF-β) 1 pathway has been associated with either syndromic or isolated mitral valve (MV) prolapse due to myxoid degeneration (floppy MV). The activation of Smad receptor-mediated intracellular TGF-β pathway and its effect on adherens junction (AJ) molecular pattern of activated valvular interstitial cells (VICs) in MV prolapse are herein investigated.

Methods: Floppy MV leaflets were obtained from 30 patients (24 males, mean age 55.5±12.7 years) who underwent surgical repair, and 10 age- and sex-matched Homograft Tissue Bank samples served as controls. MV leaflet cellular and extracellular matrix composition, including collagen I and III, was evaluated by histology and transmission electron microscopy. Smad2 active phosphorylated form (p-Smad2), α-smooth muscle actin (α-SMA), and junctional proteins (N-cadherin, cadherin-11, β-catenin, plakoglobin, plakophilin-2) in VICs were assessed by immunohistochemistry and immunofluorescence and confirmed by immunoblotting. Quantitative real-time polymerase chain reaction was carried out for components of TGF-β pathway cascade and filamin A (FLN-A).

Results: Floppy MV leaflets were thicker (P<.001) and had higher α-SMA+ cell density (P=.002) and collagen III expression (P<.001) than controls. Enhanced p-Smad2 nuclear immunoreactivity (P<.001) and TGF-β1 gene (P=.045), TIMP1 (P=.020), and CTGF (P=.047) expression but no differences in FLN-A and total Smad2 gene expression levels were found between floppy MV and controls. Higher expression of cadherin-11, either exclusively or in colocalization with N-cadherin, and aberrant presence of plakophilin-2 at the AJ were found in floppy MV vs.

Conclusions: TGF-β1 pathway activation in nonsyndromic MV prolapse induces VICs differentiation into contractile myofibroblasts and is associated with changes in the molecular pattern of the AJ, with increased cadherin-11 and aberrant plakophilin-2 expression. AJ reinforcement might promote latent TGF-β1 activation leading to extracellular matrix remodeling in floppy MV.
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http://dx.doi.org/10.1016/j.carpath.2015.07.009DOI Listing
August 2016

Homozygous Desmocollin-2 Mutations and Arrhythmogenic Cardiomyopathy.

Am J Cardiol 2015 Oct 28;116(8):1245-51. Epub 2015 Jul 28.

Department of Biology, University of Padua, Padua, Italy. Electronic address:

Dominant mutations in desmocollin-2 (DSC2) gene cause arrhythmogenic cardiomyopathy (ACM), a progressive heart muscle disease characterized by ventricular tachyarrhythmias, heart failure, and risk of juvenile sudden death. Recessive mutations are rare and are associated with a cardiac or cardiocutaneous phenotype. Here, we evaluated the impact of a homozygous founder DSC2 mutation on clinical expression of ACM. An exon-by-exon analysis of the DSC2 coding region was performed in 94 ACM index patients. The c.536A>G (p.D179G) mutation was identified in 5 patients (5.3%), 4 of which resulted to be homozygous carriers. The 5 subjects shared a conserved haplotype, strongly indicating a common founder. Genetic and clinical investigation of probands' families revealed that p.D179G homozygous carriers displayed severe forms of biventricular cardiomyopathy without hair or skin abnormalities. The only heterozygous proband, who carried an additional variant of unknown significance in αT-catenin gene, showed a mild form of ACM without left ventricular involvement. All heterozygous family members were clinically asymptomatic. In conclusion, this is the first homozygous founder mutation in DSC2 gene identified among Italian ACM probands. Our findings provide further evidence of the occurrence of recessive DSC2 mutations in patients with ACM predominantly presenting with biventricular forms of the disease.
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http://dx.doi.org/10.1016/j.amjcard.2015.07.037DOI Listing
October 2015

The ARVD/C genetic variants database: 2014 update.

Hum Mutat 2015 Apr 19;36(4):403-10. Epub 2015 Mar 19.

Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Padua, Italy; Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disease characterized by myocardial atrophy, fibro-fatty replacement, and a high risk of ventricular arrhythmias that lead to sudden death. In 2009, genetic data from 57 publications were collected in the arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) Genetic Variants Database (freeware available at http://www.arvcdatabase.info), which comprised 481 variants in eight ACM-associated genes. In recent years, deep genetic sequencing has increased our knowledge of the genetics of ACM, revealing a large spectrum of nucleotide variations for which pathogenicity needs to be assessed. As of April 20, 2014, we have updated the ARVD/C database into the ARVD/C database to contain more than 1,400 variants in 12 ACM-related genes (PKP2, DSP, DSC2, DSG2, JUP, TGFB3, TMEM43, LMNA, DES, TTN, PLN, CTNNA3) as reported in more than 160 references. Of these, only 411 nucleotide variants have been reported as pathogenic, whereas the significance of the other approximately 1,000 variants is still unknown. This comprehensive collection of ACM genetic data represents a valuable source of information on the spectrum of ACM-associated genes and aims to facilitate the interpretation of genetic data and genetic counseling.
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http://dx.doi.org/10.1002/humu.22765DOI Listing
April 2015

Nonischemic left ventricular scar: sporadic or familial? Screen the genes, scan the mutation carriers.

Circulation 2014 Nov;130(21):e180-2

From the Department of Cardiac, Thoracic, and Vascular Sciences, University of Padua, Padua, Italy (K.P., I.R., E.L., E.C., B.B., M.P.M., C.B.); Department of Radiology, Oncology, and Pathology, La Sapienza University, Rome, Italy (M.M., G.d.A.); and Radiology, Azienda Ospedaliera, Padua, Italy (B.G.).

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http://dx.doi.org/10.1161/CIRCULATIONAHA.114.012515DOI Listing
November 2014

Human SOD2 modification by dopamine quinones affects enzymatic activity by promoting its aggregation: possible implications for Parkinson's disease.

PLoS One 2012 18;7(6):e38026. Epub 2012 Jun 18.

Department of Biology, University of Padova, Padova, Italy.

Mitochondrial dysfunction and oxidative stress are considered central in dopaminergic neurodegeneration in Parkinson's disease (PD). Oxidative stress occurs when the endogenous antioxidant systems are overcome by the generation of reactive oxygen species (ROS). A plausible source of oxidative stress, which could account for the selective degeneration of dopaminergic neurons, is the redox chemistry of dopamine (DA) and leads to the formation of ROS and reactive dopamine-quinones (DAQs). Superoxide dismutase 2 (SOD2) is a mitochondrial enzyme that converts superoxide radicals to molecular oxygen and hydrogen peroxide, providing a first line of defense against ROS. We investigated the possible interplay between DA and SOD2 in the pathogenesis of PD using enzymatic essays, site-specific mutagenesis, and optical and high-field-cw-EPR spectroscopies. Using radioactive DA, we demonstrated that SOD2 is a target of DAQs. Exposure to micromolar DAQ concentrations induces a loss of up to 50% of SOD2 enzymatic activity in a dose-dependent manner, which is correlated to the concomitant formation of protein aggregates, while the coordination geometry of the active site appears unaffected by DAQ modifications. Our findings support a model in which DAQ-mediated SOD2 inactivation increases mitochondrial ROS production, suggesting a link between oxidative stress and mitochondrial dysfunction.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038026PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3377658PMC
December 2012