Whole-exome sequencing to identify causative variants in juvenile sudden cardiac death.

BACKGROUND: Juvenile sudden cardiac death (SCD) remains unexplained in approximately 40% of cases, leading to a significant emotional burden for the victims' families and society. Comprehensive investigations are essential to uncover its elusive causes and enable cascade family screening. This study aimed to enhance the identification of likely causative variants in juvenile SCD cases (age ≤ 50 years), particularly when autopsy findings are inconclusive. RESULTS: Autopsy revealed diagnostic structural abnormalities in 46%, non-diagnostic findings in 23%, and structurally normal hearts in 31% of cases. Whole-exome sequencing (WES), refined through a customized virtual gene panel was used to identify variants. These variants were then evaluated using a multidisciplinary approach and a structured variant prioritization scheme. Our extended approach identified likely causative variants in 69% of cases, outperforming the diagnostic yields of both the cardio panel and standard susceptibility gene analysis (50% and 16%, respectively). The extended cardio panel achieved an 80% diagnostic yield in cases with structurally normal hearts, demonstrating its efficacy in challenging scenarios. Notably, half of the positive cases harboured a single variant, while the remainder had two or more variants. CONCLUSION: This study highlights the efficacy of a multidisciplinary approach employing WES and a tailored virtual gene panel to elucidate the aetiology of juvenile SCD. The findings support the expansion of genetic testing using tailored gene panels and prioritization schemes as part of routine autopsy evaluations to improve the identification of causative variants and potentially facilitate early diagnosis in first-degree relatives.

Low HDL cholesterol and the eNOS Glu298Asp polymorphism are associated with inducible myocardial ischemia in patients with suspected stable coronary artery disease.

BACKGROUND: The endothelial nitric oxide synthase (eNOS) gene deficiency is known to cause impaired coronary vasodilating capability in animal models. In the general clinical population, the eNOS gene polymorphisms, able to affect eNOS activity, were associated with cardiometabolic risk features and prevalence of coronary artery disease (CAD). AIM: To investigate the association of eNOS Glu298Asp gene polymorphism, cardiometabolic profile, obstructive CAD and inducible myocardial ischemia in patients with suspected stable CAD. METHODS: A total of 506 patients (314 males; mean age 62 ± 9 years) referred for suspected CAD was enrolled. Among these, 325 patients underwent stress ECG or cardiac imaging to assess the presence of inducible myocardial ischemia and 436 patients underwent non-invasive computerized tomography or invasive coronary angiography to assess the presence of obstructive CAD. Clinical characteristics and blood samples were collected for each patient. RESULTS: In the whole population, 49.6% of patients were homozygous for the Glu298 genotype (Glu/Glu), 40.9% heterozygotes (Glu/Asp) and 9.5% homozygous for the 298Asp genotype (Asp/Asp). Obstructive CAD was documented in 178/436 (40.8%) patients undergoing coronary angiography while myocardial ischemia in 160/325 (49.2%) patients undergoing stress testing. Patients with eNOS Asp genotype (Glu/Asp + Asp/Asp) had no significant differences in clinical risk factors and in circulating markers. Independent predictors of obstructive CAD were age, gender, obesity, and low HDL-C. Independent predictors of myocardial ischemia were gender, obesity, low HDL-C and Asp genotype. In the subpopulation in which both stress tests and coronary angiography were performed, the Asp genotype remained associated with increased myocardial ischemia risk after adjustment for obstructive CAD. CONCLUSION: In this population, low-HDL cholesterol was the only cardiometabolic risk determinant of obstructive CAD. The eNOS Glu298Asp gene polymorphism was significantly associated with inducible myocardial ischemia independently of other risk factors and presence of obstructive CAD.

Prognostic value of right ventricular refractory period heterogeneity in Type-1 Brugada electrocardiographic pattern.

AIMS: To investigate the prognostic significance of heterogeneity in the refractoriness of right ventricular (RV) outflow tract (RVOT) and RV apex at the electrophysiological study (EPS) in Brugada syndrome (BrS). METHODS AND RESULTS: A cohort of BrS patients (primary prevention) from five Italian centres was retrospectively analysed. Patients with spontaneous or drug-induced Type-1 electrocardiogram (ECG) + symptoms were offered an EPS for prognostic stratification. The primary endpoint was a composite of sudden cardiac death (SCD), resuscitated cardiac arrest, or appropriate intervention by the implantable cardioverter-defibrillator (ICD). Three hundred and seventy-two patients with BrS were evaluated (44 ± 15 years, 69% males, 23% with ICD): 4 SCDs and 17 ICD interventions occurred at follow-up (median 48, interquartile range: 36-60 months). Family history of SCD, syncope, and a spontaneous Type-1 ECG pattern were univariate predictors of the primary endpoint in the whole population. In patients undergoing EPS (n = 198, 53%, 44 ± 12 years, 71% males, 39% with ICD), 3 SCD and 15 ICD interventions occurred at follow-up. In this subset, the primary endpoint was not only predicted by ventricular tachycardia/fibrillation inducibility but also by a difference in the refractory period between RVOT and RV apex (ΔRPRVOT-apex) >60 ms. ΔRPRVOT-apex > 60 ms remained an independent predictor of SCD/ICD shock at bivariate analysis, even when adjusted for the other univariate predictors, showing the highest predictive power at C-statistic analysis (0.75, 95% confidence interval 0.63-0.86). CONCLUSIONS: Heterogeneity of RV refractory periods is a strong, independent predictor of life-threatening arrhythmias in BrS patients, beyond VT/VF inducibility at EPS and common clinical predictors.

Development and validation of a risk stratification score for new-onset atrial fibrillation in STEMI patients undergoing primary percutaneous coronary intervention.

AIM: New-onset atrial fibrillation (NOAF) is a complication not infrequent in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) and has been associated with worse in-hospital and long-term prognosis. We aimed to develop and validate a risk score based on common clinical risk factors and routine blood biomarkers to assess the early incidence of NOAF post-pPCI, before discharge. METHODS: The risk score for NOAF occurrence during hospitalisation (about 5 days) was developed in a cohort of 1135 consecutive STEMI patients undergoing pPCI while was externally validated in a temporal cohort of 771 STEMI patients. Biomarkers and clinical variables significantly contributing to predicting NOAF were assessed by multivariate Cox-regression analysis. RESULTS: Independent predictors of NOAF were age ≥80 years (6.97 [3.40-14.30], hazard ratio [95% CI], P < .001), leukocyte count > 9.68 × 103 /µL (2.65 [1.57-4.48], P < .001), brain natriuretic peptide (BNP) > 80 ng/L (2.37 [1.13-4.95], P = .02) and obesity (2.07 [1.09-3.92], P = .03). By summing the hazard ratios of these predictors we derived the ALBO (acronym derived from: Age, Leucocyte, BNP and Obesity) risk score which yielded high C-statistics in both the derivation (0.734 [0.675-0.793], P < .001) and validation cohort (0.76 [0.688-0.831], P < .001). In both cohorts, using Kaplan-Meier risk analysis, the ALBO score identified a tertile of patients at highest risk (ALBO >4 points), with percentages of NOAF incidence of 30.8% and 27.4% in the derivation and validation cohort, respectively. CONCLUSION: The ALBO risk score, comprising biomarkers and clinical variables that can be assessed in hospital setting, could help to identify high-risk patients for NOAF after pPCI so that a prompter action can be taken.

A novel TGFßR2 splice variant in patient with aortic aneurysm and family history for aortic dissection: a case report.

We report the clinical presentation and genetic screening of a 31-year-old man with dilatation of the aortic root and ascending aorta and a positive family history for aortic dissection and sudden death. A novel heterozygous variant in a splice acceptor site (c.1600-1G>T) of TGFßR2 gene was identified by using a targeted multi-gene panel analysis. Bioinformatics tools predicted that the c.1600-1G>T variant is pathogenic by altering acceptor splice site at - 1 position affecting pre-mRNA splicing. These data confirm that the diverging splicing in the TGF-ß pathway genes may be an important process in aneurismal disease and emphasize the utility of genetic sequencing in the identification of high-risk patients for a more patient's management able to improve outcomes and minimize costs for the care of patients with heritable thoracic aortic aneurysm and dissection.

[Box: see text].

Magnetic Resonance Imaging Characterization and Clinical Outcomes of Dilated and Arrhythmogenic Left Ventricular Cardiomyopathies.

BACKGROUND: Nondilated left ventricular cardiomyopathy (NDLVC) has been recently differentiated from dilated cardiomyopathy (DCM). A comprehensive characterization of these 2 entities using cardiac magnetic resonance (CMR) and genetic testing has never been performed. OBJECTIVES: This study sought to provide a thorough characterization and assess clinical outcomes in a large multicenter cohort of patients with DCM and NDLVC. METHODS: A total of 462 patients with DCM (227) or NDLVC (235) with CMR data from 4 different referral centers were retrospectively analyzed. The study endpoint was a composite of sudden cardiac death or major ventricular arrhythmias. RESULTS: In comparison to DCM, NDLVC had a higher prevalence of pathogenic or likely pathogenic variants of arrhythmogenic genes (40% vs 23%; P < 0.001), higher left ventricular (LV) systolic function (LV ejection fraction: 51% ± 12% vs 36% ± 15%; P < 0.001) and higher prevalence of free-wall late gadolinium enhancement (LGE) (27% vs 14%; P < 0.001). Conversely, DCM showed higher prevalence of pathogenic or likely pathogenic variants of nonarrhythmogenic genes (23% vs 12%; P = 0.002) and septal LGE (45% vs 32%; P = 0.004). Over a median follow-up of 81 months (Q1-Q3: 40-132 months), the study outcome occurred in 98 (21%) patients. LGE with septal location (HR: 1.929; 95% CI: 1.033-3.601; P = 0.039) was independently associated with the risk of sudden cardiac death or major ventricular arrhythmias together with LV dilatation, older age, advanced NYHA functional class, frequent ventricular ectopic activity, and nonsustained ventricular tachycardia. CONCLUSIONS: In a multicenter cohort of patients with DCM and NDLVC, septal LGE together with LV dilatation, age, advanced disease, and frequent and repetitive ventricular arrhythmias were powerful predictors of major arrhythmic events.

Sequencing of NOTCH1, GATA5, TGFBR1 and TGFBR2 genes in familial cases of bicuspid aortic valve.

BACKGROUND: The purpose of our study was to investigate the potential contribution of germline mutations in NOTCH1, GATA5 and TGFBR1 and TGFBR2 genes in a cohort of Italian patients with familial Bicuspid Aortic Valve (BAV). METHODS: All the coding exons including adjacent intronic as well as 5' and 3' untranslated (UTR) sequences of NOTCH1, GATA5, TGFBR1 and TGFBR2 genes were screened by direct gene sequencing in 11 index patients (8 males; age = 42 ± 19 years) with familial BAV defined as two or more affected members. RESULTS: Two novel mutations, a missense and a nonsense mutation (Exon 5, p.P284L; Exon 26, p.Y1619X), were found in the NOTCH1 gene in two unrelated families. The mutations segregated with the disease in these families, and they were not found on 200 unrelated chromosomes from ethnically matched controls. No pathogenetic mutation was identified in GATA5, TGFBR1 and TGFBR2 genes. CONCLUSIONS: Two novel NOTCH1 mutations were identified in two Italian families with BAV, highlighting the role of a NOTCH1 signaling pathway in BAV and its aortic complications. These findings are of relevance for genetic counseling and clinical care of families presenting with BAV. Future studies are needed in order to unravel the still largely unknown genetics of BAV.

Molecular Autopsy of Sudden Cardiac Death in the Genomics Era.

Molecular autopsy is the process of investigating sudden death through genetic analysis. It is particularly useful in cases where traditional autopsy is negative or only shows non-diagnostic features, i.e., in sudden unexplained deaths (SUDs), which are often due to an underlying inherited arrhythmogenic cardiac disease. The final goal of molecular autopsy in SUD cases is to aid medico-legal inquiries and to guide cascade genetic screening of the victim's relatives. Early attempts of molecular autopsy relied on Sanger sequencing, which, despite being accurate and easy to use, has a low throughput and can only be employed to analyse a small panel of genes. Conversely, the recent adoption of next-generation sequencing (NGS) technologies has allowed exome/genome wide examination, providing an increase in detection of pathogenic variants and the discovery of newer genotype-phenotype associations. NGS has nonetheless brought new challenges to molecular autopsy, especially regarding the clinical interpretation of the large number of variants of unknown significance detected in each individual.

A novel LMNA mutation (R189W) in familial dilated cardiomyopathy: evidence for a 'hot spot' region at exon 3: a case report.

We describe a case of a patient with idiopathic dilated cardiomyopathy and cardiac conduction abnormalities who presented a strong family history of sudden cardiac death. Genetic screening of lamin A/C gene revealed in proband the presence of a novel missense mutation (R189W), near the most prevalent lamin A/C mutation (R190W), suggesting a "hot spot" region at exon 3.

[A novel lamin A/C mutation in a family with dilated cardiomyopathy and a strong history of sudden cardiac death]. / Identificazione di una nuova mutazione nel gene della lamina A/C in una famiglia con cardiomiopatia dilatativa e storia di morte improvvisa.

Diseases related to lamin A/C mutations (laminopathies) are extremely heterogeneous. The common cardiac phenotype is idiopathic dilated cardiomyopathy with atrioventricular block and/or arrhythmias. Moreover, patients with lamin A/C gene mutations are at increased risk for sudden cardiac death. Here we present a family with a strong positive history of sudden cardiac death in presence of idiopathic dilated cardiomyopathy and cardiac conduction abnormalities, related to a novel lamin A/C mutation in exon 3.

Comparison of different prediction models for the indication of implanted cardioverter defibrillator in patients with arrhythmogenic right ventricular cardiomyopathy.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with a high risk of sudden cardiac death. Three different prediction models for the indication of implanted cardioverter defibrillator (ICD) are now available: the 5 year ARVC risk score, the International Task Force Consensus (ITFC) criteria, and the Heart Rhythm Society (HRS) criteria. We compared these three prediction models in a validation cohort of patients with definite ARVC. METHODS AND RESULTS: In a cohort of 140 patients with definite ARVC, the 5 year ARVC risk score and the ITFC and HRS criteria were compared for the prediction of a major combined endpoint of sudden cardiac death, appropriate ICD intervention, resuscitated cardiac arrest, and sustained ventricular tachycardia. During the follow-up, 65 major events occurred. The 5 year ARVC risk score with a threshold >10%, derived from the maximally selected rank statistic, predicted 62 (95%) events [odds ratio (OR) 9.1, 95% confidence interval (CI) 2.6-32, P = 0.0006], the ITFC criteria 53 (81%, OR 4.8, 95% CI 2.2-10.3, P = 0.0001), and the HRS criteria 29 (45%, OR 4.2, 95% CI 1.9-9.3, P = 0.0003). At the analysis of decision curve for ICD implantation, a 5 year ARVC risk score >10% showed a greater net benefit than the ITFC and HRS criteria over a wide range of threshold probability of events. Finally, at multivariate analysis, the 5 year ARVC risk score >10% was the only independent predictor of major events. CONCLUSIONS: The 5 year score with a threshold of >10% was more effective for predicting events than the ITFC and HRS criteria.

Prognostic Value of Magnetic Resonance Phenotype in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND: Cardiac magnetic resonance (CMR) is widely used to assess tissue and functional abnormalities in arrhythmogenic right ventricular cardiomyopathy (ARVC). Recently, a ARVC risk score was proposed to predict the 5-year risk of malignant ventricular arrhythmias in patients with ARVC. However, CMR features such as fibrosis, fat infiltration, and left ventricular (LV) involvement were not considered. OBJECTIVES: The authors sought to evaluate the prognostic role of CMR phenotype in patients with definite ARVC and to evaluate the effectiveness of the novel 5-year ARVC risk score to predict cardiac events in different CMR presentations. METHODS: A total of 140 patients with definite ARVC were enrolled (mean age 42 ± 17 years, 97 males) in this multicenter prospective registry. As per study design, CMR was performed in all the patients at enrollment. The novel 5-year ARVC risk score was retrospectively calculated using the patient's characteristics at the time of enrollment. During a median follow-up of 5 years (2 to 8 years), the combined endpoint of sudden cardiac death, appropriate implantable cardioverter-defibrillator intervention, and aborted cardiac arrest was considered. RESULTS: CMR was completely negative in 14 patients (10%), isolated right ventricular (RV) involvement was found in 58 (41%), biventricular in 52 (37%), and LV dominant in 16 (12%). During the follow-up, 48 patients (34%) had major events, but none occurred in patients with negative CMR. At Kaplan-Meier analysis, patients with LV involvement (LV dominant and biventricular) had a worse prognosis than those with lone RV (p < 0.0001). At multivariate analysis, the LV involvement, a LV-dominant phenotype, and the 5-year ARVC risk score were independent predictors of major events. The estimated 5-year risk was able to predict the observed risk in patients with lone RV but underestimated the risk in those with LV involvement. CONCLUSIONS: Different CMR presentations of ARVC are associated with different prognoses. The 5-year ARVC risk score is valid for the estimation of risk in patients with lone-RV presentation but underestimated the risk when LV is involved.

Cancer risk from professional exposure in staff working in cardiac catheterization laboratory: insights from the National Research Council's Biological Effects of Ionizing Radiation VII Report.

BACKGROUND: Occupational doses from fluoroscopy-guided interventional procedures are the highest ones registered among medical staff using x-rays. The aim of the present study was to evaluate the order of magnitude of cancer risk caused by professional radiation exposure in modern invasive cardiology practice. METHODS: From the dosimetric Tuscany Health Physics data bank of 2006, we selected dosimetric data of the 26 (7 women, 19 men; age 46 +/- 9 years) workers of the cardiovascular catheterization laboratory with effective dose >2 mSv. Effective dose (E) was expressed in milliSievert, calculated from personal dose equivalent registered by the thermoluminescent dosimeter, at waist or chest, under the apron, according to the recommendations of National Council of Radiation Protection. Lifetime attributable risk of cancer was estimated using the approach of Biological Effects of Ionizing Radiation 2006 report VII. RESULTS: Cardiac catheterization laboratory staff represented 67% of the 6 workers with yearly exposure >6 mSv. Of the 26 workers with 2006 exposure >2 mSv, 15 of them had complete records of at least 10 (up to 25) consecutive years. For these 15 subjects having a more complete lifetime dosimetric history, the median individual effective dose was 46 mSv (interquartile range = 24-64). The median risk of (fatal and nonfatal) cancer (Biological Effects of Ionizing Radiation 2006) was 1 in 192 (interquartile range = 1 in 137-1 in 370). CONCLUSIONS: Cumulative professional radiological exposure is associated with a non-negligible Lifetime attributable risk of cancer for the most exposed contemporary cardiac catheterization laboratory staff.

Genetic polymorphisms in XRCC1, OGG1, APE1 and XRCC3 DNA repair genes, ionizing radiation exposure and chromosomal DNA damage in interventional cardiologists.

Interventional cardiologists working in high-volume cardiac catheterization laboratory are exposed to significant occupational radiation risks. Common single-nucleotide polymorphisms (SNPs) in DNA repair genes are thought to modify the effects of low-dose radiation exposure on DNA damage, the main initiating event in the development of cancer and hereditary disease. The aim of this study was to determine the relationship between XRCC1 (Arg194Trp and Arg399Gln), OGG1 (Ser326Cys), APE1 (Asp148Glu) and XRCC3 (Thr241Met) SNPs and chromosomal DNA damage. We enrolled 77 subjects: 40 interventional cardiologists (27 male, 41.3+/-9.4 years and 13 female, 37.8+/-8.4 years) and 37 clinical cardiologists (26 male, 39.4+/-9.5 years and 11 female, 35.0+/-9.8 years) without radiation exposure as the control group. Micronucleus (MN) assay was performed as biomarker of chromosomal DNA damage and an early predictor of cancer. MN frequency was significantly higher in interventional cardiologists than in clinical physicians (19.7+/-7.8 per thousand vs. 13.5+/-6.3 per thousand, p=0.0003). Within the exposed group, individuals carrying a XRCC3 Met241 allele had higher frequency than homozygous XRCC3 Thr241 (21.2+/-7.8 per thousand vs. 16.6+/-7.1 per thousand, p=0.03). Individuals with two or more risk alleles showed a higher MN frequency when compared to subjects with one or no risk allele (18.4+/-6.6 per thousand vs. 14.4+/-6.1 per thousand, p=0.02). An interactive effect was found between smoking, exposure >10 years and the presence of the two or more risk alleles on the MN frequency (F=6.3, p=0.02). XRCC3 241Met alleles, particularly in combination with multiple risk alleles of DNA repair genes, contribute to chromosomal DNA damage levels in interventional cardiologists.

[Patent foramen ovale: "les liaisons dangereuses" between anatomy and genetics]. / Forame ovale pervio: le relazioni pericolose fra anatomia e genetica.

We reported a case of two 24-year-old and 17-year-old male patients with episode of transient ischemic attacks and diagnosed as having patent foramen ovale (PFO). One patient had heterozygosity for the factor V Leiden mutation, and one other had heterozygosity for prothrombin G20210A mutation. Both of them were also carriers for MTHFR 677T genotype with elevated plasma levels of homocysteine (22.3 +/- 3.9 micromol/L). These findings strongly confirm and emphasize the importance of the genetic screening for thrombotic mutations in young patients with PFO-related ischemic events in order to improve secondary prevention strategies.

Clinical utility of genetic tests for inherited hypertrophic and dilated cardiomyopathies.

Genetic testing has become an increasingly important part of medical practice for heritable form of cardiomyopathies. Hypertrophic cardiomyopathy and about 50% of idiopathic dilatative cardiomyopathy are familial diseases, with an autosomal dominant pattern of inheritance.Some genotype-phenotype correlations can provide important information to target DNA analyses in specific genes. Genetic testing may clarify diagnosis and help the optimal treatment strategies for more malignant phenotypes. In addition, genetic screening of first-degree relatives can help early identification and diagnosis of individuals at greatest risk for developing cardiomyopathy, allowing to focus clinical resources on high-risk family members.This paper provides a concise overview of the genetic etiology as well as the clinical utilities and limitations of genetic testing for the heritable cardiomyopathies.

Prothrombotic mutations as risk factors for cryptogenic ischemic cerebrovascular events in young subjects with patent foramen ovale.

BACKGROUND AND PURPOSE: Patent foramen ovale (PFO) has been identified as a potential risk factor for cerebrovascular ischemia. Procoagulant mutations may increase the risk and impact the choice of appropriate therapy for secondary prevention. We evaluated the prevalence of the 2 most common genetic risk factors for thromboembolism, factor V Leiden (G1691A) and prothrombin G20210A, in young PFO patients who were referred for percutaneous transcatheter closure of their PFO. METHODS: Ninety-seven patients (50 men; mean+/-SD age, 40.9+/-10.0 years) with first-ever cerebrovascular events before the age of 55 years and 160 age-matched control subjects (69 men; mean+/-SD age, 40.4+/-10.5 years) were recruited into the study. Factor V Leiden and prothrombin G20210A mutations were detected by using a multiplex allele-specific polymerase chain reaction assay. RESULTS: The prevalence of subjects carrying at least 1 prothrombotic genotype was significantly higher in the group of PFO patients than in the group of controls (10.3% vs 2.5%; chi(2)=7.2, P=0.008). Two patients (2.1%) versus 1 control subject (0.6%) and 8 cases (8.2%) versus 3 controls (1.9%) were carriers for factor V Leiden and prothrombin G20210A mutations, respectively. After adjustment for other vascular risk factors, the combination of either factor V Leiden or prothrombin G20210A and PFO was associated with a 4.7-fold (95% CI=1.4 to 16.1; P=0.008) increased risk of cerebral ischemia in young patients. CONCLUSIONS: Our results indicate that prothrombotic mutations are important risk factors for cerebral ischemia in young patients with PFO. Screening for thrombotic mutations should be considered in young patients with PFO-related ischemic events.

GSTM1, GSTT1 and CYP1A1 detoxification gene polymorphisms and susceptibility to smoking-related coronary artery disease: a case-only study.

Cigarette smoking is a powerful risk factor for coronary artery disease (CAD), leading to the formation of DNA alterations within blood vessels and heart. However, the degree of smoking-related atherosclerosis varies from individual to individual. Genetic polymorphisms of relevant xenobiotic metabolising enzymes may determine the susceptibility of an individual response to environmental toxicants. The purpose of this study was to test the hypothesis that the inheritance of polymorphic genes encoding cytochrome P450 1A1 (CYP1A1 MspI) and glutathione S-transferases (GSTM1(null) and GSTT1(null)) may be causally associated with the presence and severity of smoking-induced CAD. In a case-only design, 222 (179 male, 57.8+/-10.3 years) consecutive smoker patients who had undergone elective and diagnostic coronary angiography were recruited. We found a group (n=169) of smoker patients with significant CAD, defined as>50% reduction in diameter of at least one major vessel, and a group without obstructive CAD (n=53). No significant differences were observed in CYP1A1 genotypes frequencies between CAD and non-CAD smokers (p=0.1). Homozygous deletion of GSTM1 had a frequency of 58.6% among patients with CAD and 45.3% among those without CAD (p=0.08). The frequency of the GSTT1(null) genotype was 43.8% among the patients with CAD and 24.5% among CAD-free subjects (p=0.01). After adjustment for traditional risk factors, the presence of combined GSTM1(null)GSTT1(null) genotypes was significantly associated with an increased risk of CAD (OR=3.9; 95% CI: 1.3-11.4, p=0.01). Moreover, smokers with combined GSTM1(null)GSTT1(null) genotypes had significantly higher number of stenosed vessels than those with the positive genotype (2.3+/-0.9 versus 1.7+/-0.8, p=0.03). Our findings showed that smokers carrying GST deleted genotypes have an increased susceptibility to the smoking related coronary artery disease. Exploring gene-smoking effect provides an excellent model in order to understand gene-environment toxicants interaction and its implications to cardiovascular disease.

Somatic DNA damage in interventional cardiologists: a case-control study.

Interventional cardiologists who work in cardiac catheterization laboratories are exposed to low doses of ionizing radiation that could pose a health hazard. DNA damage is considered to be the main initiating event by which radiation damage to cells results in development of cancer and hereditary disease. The aim of the present study was to assess the effects of chronic low-dose X-ray radiation exposure on somatic DNA damage of interventional cardiologists working in high-volume cardiac catheterization laboratories. For this analysis, we used peripheral lymphocytes and the assay for micronuclei (MNs), which is considered to be a reliable biological dosimeter for radiation exposure. We obtained peripheral blood from 62 physicians (mean age+/-se = 40.6+/-1.5 years): 31 interventional cardiologists (group I, exposed) and 31 age- and sex-matched clinical cardiologists (group II, nonexposed). Interventional cardiologists showed higher MN values (group I=20.5+/-1.6 vs. group II=12.8+/-1.3, P=0.001), although some overlap was apparent in the individual subject analysis. A correlation between years of professional activity and MN frequency value was detectable for interventional cardiologists (r=0.428, P=0.02) but not for clinical cardiologists (r=0.253, P=0.17). The results indicated that, overall, interventional cardiologists working in a high-volume catheterization laboratory have higher levels of somatic DNA damage when compared with clinical cardiologists working outside the catheterization laboratory. The amount of this damage varies and is only weakly related to the duration of professional exposure, which suggests that a dominant modulation of the underlying genetic substrate by environmental factors has a role in determining the harm in individual physicians.

Diabetes and chronic nitrate therapy as co-determinants of somatic DNA damage in patients with coronary artery disease.

Somatic DNA damage has been linked to coronary artery disease (CAD). However, whether genetic instability is linked to CAD per se or to concomitant potentially genotoxic metabolic and pharmacological factors remains still unclear. The aim of this study was to evaluate the determinants of somatic DNA damage in a large population of patients undergoing coronary angiography. A total of 278 in-hospital patients (215 men, age 61.8+/-0.7 years) were studied by using micronucleus assay (MN) in human lymphocytes, which is one of the most commonly used biomarker for somatic DNA damage. Significant CAD (>50% diameter stenosis) was present in 210 patients (179 men, age 62.3+/-0.7 years). Normal coronary arteries were observed in 68 patients (35 men, age 60.2+/-1.7 years). There were no significant differences between patients with and without CAD, but patients with multivessel disease had the highest MN levels (P=0.01). MN frequency was also found significantly higher in presence of type 2 diabetes (P<0.0001), dyslipidemia (P=0.048) and nitrate therapy (P=0.0002). A significant additive effect was also observed between diabetes and nitrate therapy (P=0.02). On multivariate logistic regression analysis, diabetes [odds ratio=6.8 (95% confidence interval, 3.2-14.5), P<0.0001] and nitrate therapy [odds ratio=2.4 (95% confidence interval, 1.3-4.7), P=0.01] remained the only significant determinants for the 50th percentile of MN (>12 per thousand). These results indicated that diabetes and, to a lesser extent, chronic nitrate therapy are major determinants of somatic DNA instability in patients with CAD. DNA damage might represent an additional pathogenetic dimension and a possible therapeutic target in the still challenging management of coronary artery disease concerning diabetics.