Biallelic EPCAM deletions induce tissue-specific DNA repair deficiency and cancer predisposition

We report a case of Mismatch Repair Deficiency (MMRD) caused by germline homozygous EPCAM deletion leading to tissue-specific loss of MSH2. Through the use of patient-derived cells and organoid technologies, we performed stepwise in vitro differentiation of colonic and brain organoids from reprogrammed EPCAMdel iPSC derived from patient fibroblasts. Differentiation of iPSC to epithelial-colonic organoids exhibited continuous increased EPCAM expression and hypermethylation of the MSH2 promoter. This was associated with loss of MSH2 expression, increased mutational burden, MMRD signatures and MS-indel accumulation, the hallmarks of MMRD. In contrast, maturation into brain organoids and examination of blood and fibroblasts failed to show similar processes, preserving MMR proficiency. The combined use of iPSC, organoid technologies and functional genomics analyses highlights the potential of cutting-edge cellular and molecular analysis techniques to define processes controlling tumorigenesis and uncovers a new paradigm of tissue-specific MMRD, which affects the clinical management of these patients.

Five waves of COVID-19 pandemic in Italy: results of a national survey evaluating the impact on activities related to arrhythmias, pacing, and electrophysiology promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

BACKGROUND

The subsequent waves of the COVID-19 pandemic in Italy had a major impact on cardiac care.

METHODS

A survey to evaluate the dynamic changes in arrhythmia care during the first five waves of COVID-19 in Italy (first: March-May 2020; second: October 2020-January 2021; third: February-May 2021; fourth: June-October 2021; fifth: November 2021-February 2022) was launched.

RESULTS

A total of 127 physicians from arrhythmia centers (34% of Italian centers) took part in the survey. As compared to 2019, a reduction in 40% of elective pacemaker (PM), defibrillators (ICD), and cardiac resynchronization devices (CRT) implantations, with a 70% reduction for ablations, was reported during the first wave, with a progressive and gradual return to pre-pandemic volumes, generally during the third-fourth waves, slower for ablations. For emergency procedures (PM, ICD, CRT, and ablations), recovery from the initial 10% decline occurred in most cases during the second wave, with some variability. However, acute care for atrial fibrillation, electrical cardioversions, and evaluations for syncope showed a prolonged reduction of activity. The number of patients with devices which started remote monitoring increased by 40% during the first wave, but then the adoption of remote monitoring declined.

CONCLUSIONS

The dramatic and profound derangement in arrhythmia management that characterized the first wave of the COVID-19 pandemic was followed by a progressive return to the volume of activities of the pre-pandemic periods, even if with different temporal dynamics and some heterogeneity. Remote monitoring was largely implemented during the first wave, but full implementation is needed.

Implantable defibrillator-detected heart failure status predicts ventricular tachyarrhythmias

Background

The occurrence of ventricular tachyarrhythmias is associated with increased mortality and hospitalizations for heart failure in implantable cardioverter defibrillator (ICD) patients. Nonetheless, the temporal relationship between heart failure worsening and ventricular tachyarrhythmias has been scarcely explored so far.

Purpose

We hypothesized that in patients with heart failure and reduced ejection fraction with ICDs, physiological sensor-based heart failure status, as reflected in the HeartLogic index, would predict appropriate device therapies for ventricular tachyarrhythmias (shocks and antitachycardia pacing).

Methods and results

568 patients implanted with ICDs (n=410, 72%) or cardiac resynchronization therapy-defibrillators (CRT-D, n=158, 28%) endowed with the HeartLogic algorithm were included in this prospective observational multicenter analysis. Over a follow-up of 25 [25th-75th percentile: 15–35] months, 122 (21%) patients received an appropriate device therapy (shock, n=74, 13%), while the HeartLogic index crossed the threshold value 1200 times (0.71 alerts/patient-year) in 370 subjects (65%). The occurrence of at least one HeartLogic alert was significantly associated with both appropriate shocks (HR: 2.44, 95% CI: 1.49–3.97, p=0.003) and any ICD therapies (HR: 1.95, 95% CI: 1.37–2.85, p=0.003). Using a time-dependent Cox model, the weekly IN-alert state was the strongest predictor of ICD shocks (HR: 2.94, 95% CI: 1.73–5.01, p<0.001), after correction for age, secondary prevention, and use of CRT. As compared to clinically stable subjects with no therapies, patients experiencing shocks had significantly higher baseline values of the HeartLogic index, third heart sound amplitude, and respiratory rate. Beginning about one month prior to the arrhythmic event, we noticed further increase of the combined index and the third heart sound amplitude, a decrease of thoracic impedance, and higher resting heart rate (Figure 1).

Conclusions

The HeartLogic index is an independent predictor of appropriate defibrillator therapies. The combined index and its individual physiological components change well before the arrhythmic event, suggesting the existence of a window of opportunity to prevent shocks.

Funding Acknowledgement

Type of funding sources: None.

P-563 The effect of embryo culture time on concordance rates between invasive and non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) in spent culture media (SCM) analysis

Study question

To evaluate different embryo culture times (day5 versus day6) to understand the ideal time-frame for the performance of concordance analysis between invasive and non-invasive PGT-A(niPGT-A)

Summary answer

Different levels of ploidy concordance rates were observed between day5 and day6 groups: 72,6% versus 84,8%, respectively

What is known already

The recent data supports that a non-invasive approach for evaluating embryo ploidy status may be an alternative to standard invasive methods. Embryo cell-free DNA(cfDNA) released into culture media during in-vitro embryo development represents the potential source for this analysis. The release of cfDNA from embryos is expected to be directly proportional to embryo culture time and late-stage released cfDNA may be more representative of the embryo. Therefore, it is important to estimate the most effective time frame of the culture that will provide the most conclusive data from spent-culture-media(SCM) without adversely affecting the development of the embryo

Study design, size, duration

A total of 334 SCM from blastocyst stage embryos have been included in this study. The SCM samples were divided in 2 subgroups according to the embryo culture time as day5 (n = 154) and day6 (n = 180). The cfDNA of SCM samples were amplified by whole genome amplification(WGA) and analyzed by next generation sequencing(NGS) in parallel to day5 or day6 trophectodermal(TE) biopsied samples of their corresponding embryos. Ploidy status and concordance were compared between two groups

Participants/materials, setting, methods

Day3 embryos were washed and transferred in 20µl fresh culture media until the biopsy. SCM samples were collected in PCR tubes and stored at -20 °C while embryos were biopsied for standard PGT-A analysis. Both SCM and corresponding TE biopsy samples were amplified by Sureplex(Vitrolife). Then TE and SCM samples were analyzed by next-generation sequencing(NGS) using MiSeq® System (Illumina). Data analysis has been done by Bluefuse Multi Software 4.5(Illumina) for all SCM and TE samples

Main results and the role of chance

A successful DNA amplification rate (>30ng/µl) was obtained in both day5 and day6 groups with 95,5% (147/154) and 99,4% (179/180) respectively. The DNA concentration after WGA was ranging between 30.1-122.5ng/µl and 38.5-123.2ng/µl in day5 and day6 groups respectively. Not conclusive (NC) results including a noisy NGS profile and chaotic chromosome aneuploidies (>5 chromosomes) were excluded in both groups. Therefore, 64,6% (95/147) of SCM samples in day5 group and 81,0% (145/179) of SCM samples in day6 group were conclusive for NGS analysis. The ploidy concordance rate between SCM and TE samples (euploid vs euploid, aneuploid vs aneuploid) was 72,6% (69/95) in day5 and 84,8% (123/145) in day6 group. In day5 group, the false-negative rate was 10.5% (10/95), and false-positive rate was 16.8% (16/95) while in day6 group the false-negative rate was 6,8% (10/145), and false-positive rate was 8,2% (12/145). Sensitivity and specificity were calculated as 83,6% and 52,9% in day5 group, and 90,9% and 65,7 in day6 group respectively

Limitations, reasons for caution

We have high number of samples in our study, but larger prospective studies may change the significance of ploidy concordance. One of the important issues in SCM analysis is the maternal DNA contamination risk which cannot be revealed always. Therefore the use of molecular markers would increase the reliability

Wider implications of the findings

A non-invasive approach for aneuploidy screening may be an alternative to standard PGT-A procedure with invasive embryo biopsy but the evaluation of ideal culture time is crucial for the performance of niPGT-A method. Our study demonstrates that the late collection time of SCM provides significantly better ploidy concordance rates

Trial registration number

Not applicable

The subcutaneous ICD replacement in the clinical practice: preliminary observations from the multicentre RHYTHM DETECT

Funding Acknowledgements

Type of funding sources: None.

Background

Experience with the subcutaneous implantable cardioverter-defibrillator (S-ICD) is expanding rapidly. However, few data on generator replacement exist.

Purpose

The aim of this analysis was to describe the procedural characteristics of the pulse generator replacement in the current Italian practice and to provide a preliminary insight in the possible acute complications associated with first elective S-ICD generator replacements.

Methods

We analyzed 106 consecutive patients enrolled in the Rhythm Detect registry who underwent elective replacement of the S-ICD generator from September 2019 to July 2021. Procedures were accomplished according to the local clinical practice. A chest X-ray was performed, and the PRAETORIAN score was assessed and compared with the one measured after the first implantation.

Results

All replacements were performed in electrophysiology laboratories, 50% in day-hospital regimen, by 1 or 2 expert operators. Procedures were performed using local (87%) or general anaesthesia (13%). The median procedure duration was 40 (30-45) min. The previous S-ICD generator was in a subcutaneous pocket in 58 (55%) patients, and in an intermuscular pocket in the remaining patients. The PRAETORIAN score of the previous system was low (<90) in 93% of patients and intermediate in 7% of patients. In all patients with the device in an intermuscular pocket, the PRAETORIAN score was <90. During the replacement procedure, 22 S-ICD (3 with PRAETORIAN ≥90 before replacement) were removed from the initial subcutaneous position and placed in an intermuscular pocket. After replacement all patients with intermuscular devices had a score <90, and the overall proportion of patients with low-risk PRAETORIAN score raised to 97%. Defibrillation testing was performed only in 10% of patients, while testing was performed in 77% of patients at the first implantation procedure. No procedure-related complications occurred.

Conclusions

S-ICD replacements seem easy to perform with no peri-procedural complications. The adoption of an intermuscular pocket is associated with optimal positioning according to the PREATORIAN score, and seems preferred also in many cases of generators previously placed subcutaneously. In the Italian clinical practice conversion testing is rarely performed at device replacement.

Device-detected sleep-disordered breathing predicts implantable defibrillator therapy in patients with heart failure

Funding Acknowledgements

Type of funding sources: None.

Background

Sleep-disordered breathing is highly prevalent in heart failure (HF) and it has been suggested as a risk factor for malignant ventricular arrhythmias. The Respiratory Disturbance Index (RDI) algorithm computed by select implantable cardioverter defibrillators (ICDs) can identify severe sleep apnea (SA).

Purpose

In the present analysis we evaluated the association between ICD-detected SA and the incidence of appropriate ICD therapy in patients with HF.

Methods

We enrolled 411 HF patients (age 69±10years, 77% male, ejection fraction 32±8%), implanted with an ICD endowed with an algorithm (ApneaScan, Boston Scientific) that calculates the RDI each night. In this analysis the weekly mean RDI value was considered. The endpoint was the first appropriate ICD shock. The median follow-up was 26 months [25th–75th percentile: 16-35].

Results

During follow-up, one or more ICD shocks were documented in 58 (14%) patients.

Patients with shocks were younger (66±13years versus 70±10years, p=0.038), and more frequently implanted for secondary prevention (21% versus 10%, p=0.026). The maximum RDI value calculated during the entire follow-up period did not differ between patients with and without shocks (55±15episodes/h versus 54±14episodes/h, p=0.539). However, the ICD-detected RDI showed a considerable variability during follow-up. The overall median of the weekly RDI was 33episodes/h [25th–75th percentile: 24-45]. Using a time-dependent Cox regression model, the continuously measured weekly mean RDI≥45episodes/h was independently associated with shock occurrence (HR:4.63, 95%CI:2.54-8.43, p<0.001), after correction for baseline confounders (age, secondary prevention).

Conclusions

In HF patients, patients were more likely to receive appropriate ICD shocks during periods of time when they exhibited more sleep-disordered breathing.

Remotely-driven management of diuretic therapy in heart failure patients with a multiparametric ICD algorithm

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific

Background

HeartLogic algorithm combines data from multiple sensors to predict future heart failure (HF) decompensation in patients with an implantable defibrillator (ICD) . An optimal strategy to manage algorithm alerts is not yet known, although decongestive treatment with diuretics is the most frequent alert-triggered action reported so far.

Purpose

We describe the implementation of HeartLogic for remote monitoring of HF patients, and we evaluate the approach to diuretic dosing and timing of the intervention in patients with device alerts.

Methods

The study was conducted in eight Italian high-volume arrhythmia centers. The algorithm was activated in 229 ICD patients during a median follow-up was 17 months [25th–75th percentile: 11-24] between December 2017 and July 2020. Remote data reviews and patient phone contacts were undertaken at the time of HeartLogic alerts, to assess the patient’s status and to prevent HF worsening. The study protocol did not mandate any specific intervention algorithm, and physicians were free to remotely implement clinical actions, to schedule extra in-office visits when deemed necessary for additional investigations or for interventions, or to adopt an active monitoring approach. We analyzed alert-triggered augmented HF treatments, consisting of isolated increases in diuretics dosage.

Results

We reported 242 alerts (0.8 alerts/patient-year) in 123 patients, 137 (56%) alerts triggered clinical actions to treat HF. Overall, timely diuretic changes were associated with a shorter "in-alert" state duration in comparison with late changes, i.e. 28 days [25th-75th percentile: 20-43] versus 62 days [25th-75th percentile: 44-118], p<0.001. By contrast, major and minor diuretic augmentations resulted in comparable durations, i.e. 47 days [25th-75th percentile: 30-58] versus 38 days [25th-75th percentile: 23-79], p=0.954. Of the 56 decongestive treatment adjustments, 47 resolved the alert condition, while in the remaining 9 cases, further treatments were required (augmented HF therapy during hospitalization or unscheduled intravenous decongestive therapy in outpatients). The need of hospitalization for further treatments to resolve the alert condition was associated with higher HeartLogic index values on the day of the diuretics increase (odds ratio: 1.11, 95%CI: 1.02-1.20, p=0.013) and with late interventions (odds ratio: 5.11, 95%CI: 1.09-24.48, p=0.041). No complications were reported after drug adjustments.

Conclusions

Decongestive treatment adjustments triggered by HeartLogic alerts, even when such adjustments were completely dependent on the physicians’ clinical expertise and were not standardized. The early use of decongestive treatment and the use of high doses of diuretics seem to be associated with more favorable outcomes.

P–582 High level of concordance between invasive and non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) at day5 and day6–7

Study question

To explore ploidy concordance between invasive and non-invasive PGTA (niPGT-A) at different embryo culture time.

Summary answer

High level (>84%) of concordance rate for ploidy and sex, sensitivity (>88%), and specificity (76%) were obtained for both day6/7 samples and day5 samples.

What is known already

The analysis of embryo cell free DNA (cfDNA) that are released into culture media during in vitro embryo development has the potential to evaluate embryo ploidy status. However, obtaining sufficient quality and quantity of cfDNA is essential to achieve interpretable results for niPGT-A. More culture time is expected to be directly proportional to the release of more cfDNA. But embryo culture time is limited due to in-vitro embryo survival potential. Therefore, it is important to estimate the duration of the culture that will provide the maximum cfDNA that can be obtained without adversely affecting the development of the embryo.

Study design, size, duration

A total of 105 spent culture media (SCM) from day5-day7 blastocyst stage embryos have been included in this cohort study. The cfDNA of SCM samples were amplified and analyzed for niPGT-A by NGS analysis. The SCM samples were divided into 2 subgroups according the embryo culture hours (Day5 and Day6/7 group). The DNA concentration, informativity and euploidy results have then been compared with their corresponding embryos after trophectoderm biopsy (TE) and PGT-A analysis by NGS

Participants/materials, setting, methods

Embryos cultured until Day3 washed and cultured again in 20µl fresh culture media until embryo biopsy on Day5, 6, or 7. After biopsy SCM samples were immediately collected in PCR tubes and conserved at –20 °C until whole genome amplification by MALBAC® (Yicon Genomics). The TE and SCM samples were analyzed by next-generation sequencing (NGS) using Illumina MiSeq® System. NGS data analysis has been done by Bluefuse Multi Software 4.5 (Illumina) for SCM and TE samples

Main results and the role of chance

Only the SCM samples which have an embryo with a conclusive result were included in this cohort (n = 105). Overall 97.1% (102/105) of SCM samples gave a successful DNA amplification with a concentration ranging 32.4–128.5ng/µl. Non-informative (NI) results including a chaotic profile (>5 chromosome aneuploidies) were observed in 17 samples, so 83.3%(85/102) of SCM samples were informative for NGS data analysis. Ploidy concordance rate with the corresponding TE biopsies (euploid vs euploid, aneuploid vs aneuploid) was 84.7% (72/85). Sensitivity and specificity were 92,8% and 76,7%, respectively with no significant difference for all parameters for day 6/7 samples compared with day 5 samples. The false-negative rate was 3.5% (3/85), and false-positive rate was 11.7% (10/85).

Limitations, reasons for caution

The sample size is relatively small. Larger prospective studies are needed. As this is a single-center study, the impact of the variations in embryo culture conditions can be underestimated. Maternal DNA contamination risk cannot be revealed in SCM, therefore the use of molecular markers would increase the reliability.

Wider implications of the findings: Non-invasive analysis of embryo cfDNA analyzed in spent culture media demonstrates high concordance with TE biopsy results in both early and late culture time. A non-invasive approach for aneuploidy screening offers important advantages such as avoiding invasive embryo biopsy and decreased cost, potentially increasing accessibility for a wider patient population.

Trial registration number

Not applicable

A multiparametric ICD algorithm for heart failure risk stratification and management: an analysis in clinical practice

Funding Acknowledgements

Type of funding sources: None.

Introduction

The HeartLogic algorithm combines multiple implantable cardioverter defibrillator (ICD) sensors to identify patients at risk of heart failure (HF) events.

Purpose

We sought to evaluate the risk stratification ability of this algorithm in clinical practice. We also analyzed the alert management strategies adopted in the study group and their association with the occurrence of HF events.

Methods

The HeartLogic feature was activated in 366 ICD and cardiac resynchronization therapy ICD patients at 22 centers. The HeartLogic algorithm automatically calculates a daily HF index and identifies periods IN or OUT of an alert state on the basis of a configurable threshold (in this analysis set to 16).

Results

The HeartLogic index crossed the threshold value 273 times (0.76 alerts/patient-year) in 150 patients over a median follow-up of 11 months [25-75 percentile: 6-16]. Overall, the time IN the alert state was 11% of the total observation period. Patients experienced 36 HF hospitalizations and 8 patients died of HF (rate: 0.12 events/patient-year) during the observation period. Thirty-five events were associated with the IN alert state (0.92 events/patient-year versus 0.03 events/patient-year in the OUT of alert state). The hazard ratio in the IN/OUT of alert state comparison was (HR: 24.53, 95% CI: 8.55-70.38, p < 0.001), after adjustment for baseline clinical confounders. Alerts followed by clinical actions were associated with a lower rate of HF events (HR: 0.37, 95% CI: 0.14-0.99, p = 0.047). No differences in event rates were observed between in-office and remote alert management. By contrast, verification of HF symptoms during post-alert examination was associated with a higher risk of HF events (HR: 5.23, 95% CI: 1.98-13.83, p < 0.001).

Conclusions

This multiparametric ICD algorithm identifies patients during periods of significantly increased risk of HF events. The rate of HF events seemed lower when clinical actions were undertaken in response to alerts. Extra in-office visits did not seem to be required in order to effectively manage HeartLogic alerts, while post-alert verification of symptoms seemed useful in order to better stratify patients at risk of HF events.

Safety of omitting defibrillation efficacy testing with subcutaneous defibrillators: a propensity matched case-control study

Funding Acknowledgements

Type of funding sources: None.

Background

Defibrillation efficacy testing (DT) is recommended at implantation of subcutaneous implantable cardioverter–defibrillators (S-ICD). However, prior works found that adherence to this recommendation is declining in clinical practice.

Purpose

To compare survival from all-cause death and first ineffective shock (primary endpoint) and the composite of all-cause death, ineffective shock, inappropriate shock and device-related complication (secondary endpoint) between patients who underwent DT and those with omitted DT.

Methods

We analyzed 1652 consecutive patients who underwent S-ICD implantation in 60 Italian centers from 2013 to 2019.

Results

DT was not performed in 325 (20%) patients (no-DT patients). As compared with the DT group, these patients were older (51 ± 16 vs. 48 ± 15 years; p < 0.01) and had lower ejection fraction (37 ± 16% vs. 46 ± 16%; p < 0.01). The 325 no-DT patients were propensity matched with 325 patients of the DT group. During a median follow up of 19 months, 27 (4.2%) patients died for any-cause. During follow-up, 34 (5.2%) patients received appropriate shocks to treat discrete episodes of VT/VF. The first shock was effective in 30 out of 34 patients (88%), whereas a second shock was required to terminate VT/VF in 3 patients and a third shock in the last one. The primary endpoint occurred in 31 (4.8%) patients, and the risk was not significantly increased in the no-DT cohort (HR = 1.26, 95%CI:0.62-2.55, p = 0.522). Inappropriate shocks were reported in 36 (5.5%) patients and device-related complications in 25 (3.8%) patients during follow-up. Survival from the composite secondary endpoint was comparable between groups (HR = 0.86, 95%CI:0.57-1.32, p = 0.500).

Conclusions

Our data confirmed that DT is frequently omitted in current clinical practice, especially in older patients with worse systolic function. A strategy that omits DT did not appear to compromise the effectiveness of the S-ICD and no additional risk seems associated with DT omission at a mid-term follow-up. These data suggest that routine DT at S-ICD implant might not be necessary. Randomized trials are needed to confirm this finding.

Epigenetic Analyses of Human Left Atrial Tissue Identifies Gene Networks Underlying Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) often arises from structural abnormalities in the left atria (LA). Annotation of the noncoding genome in human LA is limited, as are effects on gene expression and chromatin architecture. Many AF-associated genetic variants reside in noncoding regions; this knowledge gap impairs efforts to understand the molecular mechanisms of AF and cardiac conduction phenotypes.

METHODS

We generated a model of the LA noncoding genome by profiling 7 histone post-translational modifications (active: H3K4me3, H3K4me2, H3K4me1, H3K27ac, H3K36me3; repressive: H3K27me3, H3K9me3), CTCF binding, and gene expression in samples from 5 individuals without structural heart disease or AF. We used MACS2 to identify peak regions (P<0.01), applied a Markov model to classify regulatory elements, and annotated this model with matched gene expression data. We intersected chromatin states with expression quantitative trait locus, DNA methylation, and HiC chromatin interaction data from LA and left ventricle. Finally, we integrated genome-wide association data for AF and electrocardiographic traits to link disease-related variants to genes.

RESULTS

Our model identified 21 epigenetic states, encompassing regulatory motifs, such as promoters, enhancers, and repressed regions. Genes were regulated by proximal chromatin states; repressive states were associated with a significant reduction in gene expression (P<2×10-16). Chromatin states were differentially methylated, promoters were less methylated than repressed regions (P<2×10-16). We identified over 15 000 LA-specific enhancers, defined by homeobox family motifs, and annotated several cardiovascular disease susceptibility loci. Intersecting AF and PR genome-wide association studies loci with long-range chromatin conformation data identified a gene interaction network dominated by NKX2-5, TBX3, ZFHX3, and SYNPO2L.

CONCLUSIONS

Profiling the noncoding genome provides new insights into the gene expression and chromatin regulation in human LA tissue. These findings enabled identification of a gene network underlying AF; our experimental and analytic approach can be extended to identify molecular mechanisms for other cardiac diseases and traits.

BAZ2A safeguards genome architecture of ground-state pluripotent stem cells

Chromosomes have an intrinsic tendency to segregate into compartments, forming long-distance contacts between loci of similar chromatin states. How genome compartmentalization is regulated remains elusive. Here, comparison of mouse ground-state embryonic stem cells (ESCs) characterized by open and active chromatin, and advanced serum ESCs with a more closed and repressed genome, reveals distinct regulation of their genome organization due to differential dependency on BAZ2A/TIP5, a component of the chromatin remodeling complex NoRC. On ESC chromatin, BAZ2A interacts with SNF2H, DNA topoisomerase 2A (TOP2A) and cohesin. BAZ2A associates with chromatin sub-domains within the active A compartment, which intersect through long-range contacts. We found that ground-state chromatin selectively requires BAZ2A to limit the invasion of active domains into repressive compartments. BAZ2A depletion increases chromatin accessibility at B compartments. Furthermore, BAZ2A regulates H3K27me3 genome occupancy in a TOP2A-dependent manner. Finally, ground-state ESCs require BAZ2A for growth, differentiation, and correct expression of developmental genes. Our results uncover the propensity of open chromatin domains to invade repressive domains, which is counteracted by chromatin remodeling to establish genome partitioning and preserve cell identity.

Epigenetic and Transcriptional Networks Underlying Atrial Fibrillation

Genome-wide association studies have uncovered over a 100 genetic loci associated with atrial fibrillation (AF), the most common arrhythmia. Many of the top AF-associated loci harbor key cardiac transcription factors, including PITX2, TBX5, PRRX1, and ZFHX3. Moreover, the vast majority of the AF-associated variants lie within noncoding regions of the genome where causal variants affect gene expression by altering the activity of transcription factors and the epigenetic state of chromatin. In this review, we discuss a transcriptional regulatory network model for AF defined by effector genes in Genome-wide association studies loci. We describe the current state of the field regarding the identification and function of AF-relevant gene regulatory networks, including variant regulatory elements, dose-sensitive transcription factor functionality, target genes, and epigenetic states. We illustrate how altered transcriptional networks may impact cardiomyocyte function and ionic currents that impact AF risk. Last, we identify the need for improved tools to identify and functionally test transcriptional components to define the links between genetic variation, epigenetic gene regulation, and atrial function.

P538Single- and Multi-Site Pacing Strategies for Optimal Cardiac Resynchronization Therapy: Impact on Device Longevity and Therapy Cost

Funding Acknowledgements

No funding

Introduction

Multiple left ventricular pacing strategies have been suggested for improving response to cardiac resynchronization therapy (CRT). However, these programming strategies can be obtained by accepting configurations with high pacing threshold and accelerated battery drain. We assessed the feasibility of predefined pacing programming protocols and we evaluated their impact on device longevity and their cost-impact.

Methods

We estimated battery longevity in 167 CRT-D (RESONATE, Boston Scientific) patients based on measured pacing parameters and according to multiple programming strategies: single-site pacing associated with lowest threshold, non-apical location, longest interventricular delay, pacing from two electrodes. To determine the economic impact of each programming strategy, we applied the results of a published model-based cost analysis to a 15-year time-horizon.

Results

Selecting the electrode with the lowest threshold resulted in a median device longevity of 11.5 years. Non-apical pacing and interventricular delay maximization were feasible in most patients (99% non-apical pacing, 65% RV-to-LV interval &gt;80ms), and were obtained at the price of a few months of battery life. Device longevity of &gt;10 years was preserved in 87% of cases of non-apical pacing and in 77% on pacing at the longest interventricular delay. The mean reduction in battery life when the second electrode was activated was 1.5 years. Single-site pacing strategies increased the therapy cost by 4-6%, and multi-site pacing by 12-13%, in comparison with the best-case scenario.

Conclusions

Modern CRT-D systems ensure effective pacing and allow multiple optimization strategies for maximizing service life or for enhancing effectiveness. Single- or multi-site pacing strategies can be implemented without compromising device service life and at an acceptable increase in therapy cost.

Abstract Figure. Image1

P521Conversion test during Subcutaneous Implantable Cardioverter-Defibrillator Implantation in clinical practice: in-hospital and mid-term outcome

Funding Acknowledgements

No funding

OnBehalf

RHYTHM DETECT Registry

Background

With subcutaneous implantable cardioverter–defibrillators (S-ICD), conversion test (CT) is still recommended at implantation. However, prior works found that adherence to this recommendation is declining in clinical practice.

Purpose

To describe current practice regarding CT at S-ICD implantation, and also measure in-hospital outcome of patients who underwent CT and mid-term outcome of patients without CT.

Methods

We analyzed 1652 consecutive patients (49 ± 15 years old, 80% male, 51% with ischemic or non-ischemic dilated cardiomyopathy, 45% with ejection fraction ≤35%) who underwent S-ICD implantation in 60 Italian centers from 2013 to 2019.

Results

CT data were missing in 27 patients. CT was performed in 1300 patients. Successful conversion with ≤65J was obtained in 97.4% of patients. Shock at 80J was not effective in 12 (0.9%) patients. In 10 of these patients the CT was successful after device repositioning, while in 2 patients it was decided to implant a transvenous ICD. Two (0.15%) episodes of electromechanical dissociation (1 fatal) were reported as consequence of CT. CT was not performed in 325 patients (for clinical reasons in 182 patients, for facility preference in 71, ventricular fibrillation not inducible in 72 patients). As compared to the CT group, these patients were older (51 ± 16 vs. 48 ± 15 years; p &lt; 0.01) and had lower ejection fraction (37 ± 16% vs. 46 ± 16%; p &lt; 0.01). 243 non-CT patients had at least 6 months follow-up (median 15 months). In this group, 12 (4.9%) patients had appropriate shocks to treat VT/VF (all successfully terminated with the first shock), and 9 (3.7%) patients had inappropriate shocks.

Conclusions

This analysis showed that CT is frequently omitted in current clinical practice, especially in older patients with worse systolic function. Shocks at CT are very frequently effective and system revision after CT is rarely required. CT is also safe, although serious adverse events cannot be excluded. A strategy that omits CT did not appear to compromise the effectiveness of the S-ICD, but larger populations and longer follow-up are needed to confirm this finding.

P526Are 40 joules enough for successfully defibrillate with subcutaneous implantable cardioverter-defirbrillator?

Funding Acknowledgements

NO FUNDING

OnBehalf

Rhythm Detect Registry

Background

The subcutaneous ICD (S-ICD) is an effective alternative to the traditional transvenous option. Due to its extracardiac design the S-ICD requires a higher shock output than the traditional ICD. Nonetheless, preliminary data suggest that acute defibrillation test may be successful even at energies lower than the usually tested value of 65J, and that optimization of implantation technique may increase the defibrillation safety margin among S-ICD recipients.

Purpose

To evaluate the efficacy of conversion test performed at 40J, and to investigate the association between shock efficacy, clinical characteristics and device position.

Methods

VF was induced and subsequently, conversion test was performed by delivering a 40J shock. Success was defined as termination of VF by the first shock. S-ICD system positioning was evaluated with the PRAETORIAN score using bidirectional chest X-rays. Cranial-caudal S-ICD placement was defined as superior if the entire generator was contained in the cardiac silhouette, inferior if partially or completely outside.

Results

233 consecutive patients (83% male, 49 ± 14 years, BMI 26 ± 4kg/m2, ejection fraction 46 ± 17%, 112 (48%) ischemic/non-ischemic dilated cardiomyopathy) were enrolled and underwent S-ICD implantation with conversion test at 40J. The generator was positioned in an intermuscular pocket in 228 patients (98%). The PRAETORIAN score was &lt;90 (low risk of conversion failure) in 218 (94%) patients. Cranial-caudal generator placement was superior in 188 (81%) patients. Overall, VF termination occurred in 191 (82%) patients with 40J. The BMI was similar in patients with successful and unsuccessful termination (26 ± 4kg/m2 versus 27 ± 6kg/m2, p = 0.195). The efficacy was comparable in patients with dilated cardiomyopathy (86%) versus other conditions (79%, p = 0.153). PRAETORIAN score was not associated with shock efficacy at 40J (82% with score &lt;90 versus 87% with score ≥90, p = 1.000), while a trend toward higher efficacy was seen with superior generator placement (84% versus 73%, p = 0.093).

Conclusions

We observed high S-ICD defibrillation success rate at 40J, suggesting that the safety margin is frequently higher than the usually accepted 15J. We found no difference in efficacy according to the cardiac disease and no association between test failure and body habitus. The intermuscular positioning of the generator resulted in low values of the PRAETORIAN score that however did not appear associated with test efficacy.

855Performance of a multisensor icd algorithm in heart failure patient management

Funding Acknowledgements

No funding

Background

The HeartLogic index combines data from multiple implantable cardioverter-defibrillator (ICD)-based sensors and has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation.

Purpose

To describe a multicenter experience of remote HF management of patients who received a HeartLogic-enabled ICD or cardiac resynchronization therapy ICD (CRT-D).

Methods

The HeartLogic feature was activated in 104 patients (76 male, 71 ± 10 years, left ventricular ejection fraction 29 ± 7%). In accordance with a standardized follow-up protocol, remote data reviews and patient phone contacts were performed monthly and at the time of HeartLogic alerts (when the index crossed the nominal threshold value of 16), to assess the patient decompensation status. In-office visits were performed every 6 months or when deemed necessary.

Results

During a median follow-up of 13[11-18] months, 100 HeartLogic alerts were reported (0.82 alerts/pt-year) in 53 patients. 60 HeartLogic alerts were judged clinically meaningful (i.e. associated with worsening of HF or resulted in active clinical actions). Specifically, multiple associated conditions were reported: 45 (75%) symptoms or signs of clinical deterioration of HF, 13 (22%) discontinuations or reductions of prescribed HF therapy, 11 (18%) declines in CRT percentage (with or without new onset atrial fibrillation), 8 (13%) recurrences of previous HF events. For 48 out of 60 alerts the clinician was not previously aware of the condition. Of these, 43 alerts triggered multiple clinical actions. Alert-triggered actions were: 30 (70%) diuretic dosage increases, 15 (35%) other drug adjustments, 6 (14%) HF hospitalizations, 3 (7%) device reprogramming/revisions, 1 (2%) cardioversion, 1 (2%) patient education on therapy adherence. Out of 40 non-clinically meaningful alerts (0.33 alerts/pt-year), 8 (20%) were associated with non-HF therapy changes or interventions, 3 (8%) with pulmonary events, 29 (72%) remained unexplained. The overall number of HF hospitalizations was 16 (rate 0.13 hospitalizations/pt-year). Five HF hospitalizations were not preceded by HeartLogic alert (0.04 hospitalizations/pt-year).

Conclusions

The HeartLogic index provided clinically meaningful information and allowed to remotely identify relevant HF related clinical conditions, with a low rate of unexplained detections and undetected HF events. In this experience, remote monitoring using HeartLogic alerts allowed to drive HF care and take effective clinical actions.

Hominin-specific regulatory elements selectively emerged in oligodendrocytes and are disrupted in autism patients

Speciation is associated with substantial rewiring of the regulatory circuitry underlying the expression of genes. Determining which changes are relevant and underlie the emergence of the human brain or its unique susceptibility to neural disease has been challenging. Here we annotate changes to gene regulatory elements (GREs) at cell type resolution in the brains of multiple primate species spanning most of primate evolution. We identify a unique set of regulatory elements that emerged in hominins prior to the separation of humans and chimpanzees. We demonstrate that these hominin gains perferentially affect oligodendrocyte function postnatally and are preferentially affected in the brains of autism patients. This preference is also observed for human-specific GREs suggesting this system is under continued selective pressure. Our data provide a roadmap of regulatory rewiring across primate evolution providing insight into the genomic changes that underlie the emergence of the brain and its susceptibility to neural disease.

The understanding of the changes regulating gene expression relevant for the emergence of the human brain and its susceptibility to disease is limited. Here, the authors identified a set of regulatory elements that evolved in hominins affecting oligodendrocyte function, and link these to autism.

Combined flow-based imaging assessment of optimal cardiac resynchronization therapy pacing vector: a case report

Background

There are still many pendent issues about the effective evaluation of cardiac resynchronization therapy impact on functional mitral regurgitation. In order to reduce the intrinsic difficulties of quantification of functional mitral regurgitation itself, an automatic quantification of real-time three-dimensional full-volume color Doppler transthoracic echocardiography was proposed as a new, rapid, and accurate method for the assessment of functional mitral regurgitation severity. Recent studies suggested that images of left ventricle flow by echo-particle imaging velocimetry could be a useful marker of synchrony. Echo-particle imaging velocimetry has shown that regional anomalies of synchrony/synergy of the left ventricle are related to the alteration, reduction, or suppression of the physiological intracavitary pressure gradients.

Case summary

We describe a case in which the two technologies are used in combination during acute echocardiographic optimization of left pacing vector in a 63-year-old man, Caucasian, who showed worsening heart failure symptoms a few days after an implant, and the effect of the device’s optimization at 6-month follow-up.

Discussion

The degree of realignment of hemodynamic forces, with quantitative analysis of the orientation of blood flow momentum (φ), can represent improvement of fluid dynamics synchrony of the left ventricle, and explain, with a new deterministic parameter, the effects of cardiac resynchronization therapy on functional mitral regurgitation. Real-time three-dimensional color flow Doppler quantification is feasible and accurate for measurement of mitral inflow, left ventricular outflow stroke volumes, and functional mitral regurgitation severity.

Conclusion

This clinical case offers an innovative and accurate approach for acute echocardiographic optimization of left pacing vector. It shows clinical utility of combined three-dimensional full-volume color Doppler transthoracic echocardiography/echo-particle imaging velocimetry assessment to increase response to cardiac resynchronization therapy, in terms of reduction of functional mitral regurgitation, improving fluid dynamics synchrony of the left ventricle.

Electronic supplementary material

The online version of this article (10.1186/s13256-019-2048-1) contains supplementary material, which is available to authorized users.

An enhancer cluster controls gene activity and topology of the SCN5A-SCN10A locus in vivo

Mutations and variations in and around SCN5A, encoding the major cardiac sodium channel, influence impulse conduction and are associated with a broad spectrum of arrhythmia disorders. Here, we identify an evolutionary conserved regulatory cluster with super enhancer characteristics downstream of SCN5A, which drives localized cardiac expression and contains conduction velocity-associated variants. We use genome editing to create a series of deletions in the mouse genome and show that the enhancer cluster controls the conformation of a >0.5 Mb genomic region harboring multiple interacting gene promoters and enhancers. We find that this cluster and its individual components are selectively required for cardiac Scn5a expression, normal cardiac conduction and normal embryonic development. Our studies reveal physiological roles of an enhancer cluster in the SCN5A-SCN10A locus, show that it controls the chromatin architecture of the locus and Scn5a expression, and suggest that genetic variants affecting its activity may influence cardiac function.

Thyroid Hormone and Thyrotropin Regulate Intracellular Free Calcium Concentrations in Human Polymorphonuclear Leukocytes: In Vivo and in vitro Studies

Intracellular free calcium concentrations ([Ca++]1) were studied in polymorphonuclear leukocytes (PMNs) from 13 athyreotic patients who had been previously treated by total thyroidectomy and radioiodine therapy for differentiated thyroid carcinoma, and from age- and sex-matched euthyroid healthy controls. Patients were studied twice, when hypothyroid (visit 1) and after restoration of euthyroidism by L-T4 TSH-suppressive therapy (visit 2). PMNs from patients at visit 1 had significantly lower resting [Ca++]1 levels compared to both visit 2 and controls. Values at visit 2 did not differ from those of the controls. Stimulus-induced [Ca++]1 rise was also significantly blunted at visit 1 and normalized at visit 2, possibly through a differential contribution of distinct intracellular Ca++ stores, as suggested by the response pattern to the chemotactic agent, N-formyl-Met-Leu-Phe (fMLP), to the selective SERCA pump inhibitor, thapsigargine, and to the mitochondrial uncoupler, carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone (FCCP). In vitro treatment of PMNs from healthy subjects with high TSH concentrations impaired intracellular Ca++ store function. Both resting [Ca++]1 levels and fMLP-induced [Ca++]1 rise increased in the presence either of low-concentration TSH or of T4, but effects of TSH and T4 were not additive. T3, rT3, and TRIAC had no effect. In conclusion, this study provides evidence for a direct relationship between thyroid status and [Ca[Ca++]1 homeostasis in human PMNs, mainly related to direct actions of TSH and T4 on these cells.

The mitochondrial translation machinery as a therapeutic target in Myc-driven lymphomas

The oncogenic transcription factor Myc is required for the progression and maintenance of diverse tumors. This has led to the concept that Myc itself, Myc-activated gene products, or associated biological processes might constitute prime targets for cancer therapy. Here, we present an in vivo reverse-genetic screen targeting a set of 241 Myc-activated mRNAs in mouse B-cell lymphomas, unraveling a critical role for the mitochondrial ribosomal protein (MRP) Ptcd3 in tumor maintenance. Other MRP-coding genes were also up regulated in Myc-induced lymphoma, pointing to a coordinate activation of the mitochondrial translation machinery. Inhibition of mitochondrial translation with the antibiotic Tigecycline was synthetic-lethal with Myc activation, impaired respiratory activity and tumor cell survival in vitro, and significantly extended lifespan in lymphoma-bearing mice. We have thus identified a novel Myc-induced metabolic dependency that can be targeted by common antibiotics, opening new therapeutic perspectives in Myc-overexpressing tumors.

Transcription-factor-dependent enhancer transcription defines a gene regulatory network for cardiac rhythm

The noncoding genome is pervasively transcribed. Noncoding RNAs (ncRNAs) generated from enhancers have been proposed as a general facet of enhancer function and some have been shown to be required for enhancer activity. Here we examine the transcription-factor-(TF)-dependence of ncRNA expression to define enhancers and enhancer-associated ncRNAs that are involved in a TF-dependent regulatory network. TBX5, a cardiac TF, regulates a network of cardiac channel genes to maintain cardiac rhythm. We deep sequenced wildtype and Tbx5-mutant mouse atria, identifying ~2600 novel Tbx5-dependent ncRNAs. Tbx5-dependent ncRNAs were enriched for tissue-specific marks of active enhancers genome-wide. Tbx5-dependent ncRNAs emanated from regions that are enriched for TBX5-binding and that demonstrated Tbx5-dependent enhancer activity. Tbx5-dependent ncRNA transcription provided a quantitative metric of Tbx5-dependent enhancer activity, correlating with target gene expression. We identified RACER, a novel Tbx5-dependent long noncoding RNA (lncRNA) required for the expression of the calcium-handling gene Ryr2. We illustrate that TF-dependent enhancer transcription can illuminate components of TF-dependent gene regulatory networks.

Schistocytic anaemia, severe thrombocytopenia, and renal dysfunction: thrombotic microangiopathy due to severe acquired ADAMTS-13 deficiency

We present the case of a woman (age: 64 years) with acute thrombotic microangiopathy due to severe acquired ADAMTS-13 (von Willebrand factor-cleaving protease) deficiency. She was successfully treated with plasma exchange therapy and glucocorticosteroids. She relapsed seven months later, and splenectomy led to lasting remission.

Pathomechanisms of thrombotic thrombocytopenic purpura, especially the role of ADAMTS-13, are discussed and therapeutic measures outlined.

A Genetic Variant Associated with Five Vascular Diseases Is a Distal Regulator of Endothelin-1 Gene Expression

Genome-wide association studies (GWASs) implicate the PHACTR1 locus (6p24) in risk for five vascular diseases, including coronary artery disease, migraine headache, cervical artery dissection, fibromuscular dysplasia, and hypertension. Through genetic fine mapping, we prioritized rs9349379, a common SNP in the third intron of the PHACTR1 gene, as the putative causal variant. Epigenomic data from human tissue revealed an enhancer signature at rs9349379 exclusively in aorta, suggesting a regulatory function for this SNP in the vasculature. CRISPR-edited stem cell-derived endothelial cells demonstrate rs9349379 regulates expression of endothelin 1 (EDN1), a gene located 600 kb upstream of PHACTR1. The known physiologic effects of EDN1 on the vasculature may explain the pattern of risk for the five associated diseases. Overall, these data illustrate the integration of genetic, phenotypic, and epigenetic analysis to identify the biologic mechanism by which a common, non-coding variant can distally regulate a gene and contribute to the pathogenesis of multiple vascular diseases.

Mutual epithelium-macrophage dependency in liver carcinogenesis mediated by ST18

The ST18 gene has been proposed to act either as a tumor suppressor or as an oncogene in different human cancers, but direct evidence for its role in tumorigenesis has been lacking thus far. Here, we demonstrate that ST18 is critical for tumor progression and maintenance in a mouse model of liver cancer, based on oncogenic transformation and adoptive transfer of primary precursor cells (hepatoblasts). ST18 messenger RNA (mRNA) and protein were detectable neither in normal liver nor in cultured hepatoblasts, but were readily expressed after subcutaneous engraftment and tumor growth. ST18 expression in liver cells was induced by inflammatory cues, including acute or chronic inflammation in vivo, as well as coculture with macrophages in vitro. Knocking down the ST18 mRNA in transplanted hepatoblasts delayed tumor progression. Induction of ST18 knockdown in pre-established tumors caused rapid tumor involution associated with pervasive morphological changes, proliferative arrest, and apoptosis in tumor cells, as well as depletion of tumor-associated macrophages, vascular ectasia, and hemorrhage. Reciprocally, systemic depletion of macrophages in recipient animals had very similar phenotypic consequences, impairing either tumor development or maintenance, and suppressing ST18 expression in hepatoblasts. Finally, RNA sequencing of ST18-depleted tumors before involution revealed down-regulation of inflammatory response genes, pointing to the suppression of nuclear factor kappa B-dependent transcription.

CONCLUSION

ST18 expression in epithelial cells is induced by tumor-associated macrophages, contributing to the reciprocal feed-forward loop between both cell types in liver tumorigenesis. Our findings warrant the exploration of means to interfere with ST18-dependent epithelium-macrophage interactions in a therapeutic setting. (Hepatology 2017;65:1708-1719).

Telangiectases in Venous Insufficiency: Point of Reflux and Treatment Strategy

Objective:

To verify the role of sources of non-saphenous reflux in the appearance of reticular varices and telangiectases in areas other than the lateral venous system of Albanese.

Setting:

Institute of General Surgery and Surgical Specialisations, Interdepartmental Centre of Research, Treatment and Phlebolymphological Rehabilitation, University of Siena.

Patients and methods:

The study was carried out on 106 women aged 18–65 years who were affected by chronic venous insufficiency (CVI) at the Cla-s Ep Asl stage, according to the CEAP classification. The patients had telangiectases (200 telangiectactic areas) and reticular varices of the lower limbs of type II and III of the classification of Weiss, with competent saphenous trunks and a normal deep venous system. Sclerotherapy was therefore performed, after clinical and duplex ultrasound examination. The records of 185 telangiectactic area treated 3 years earlier were reviewed.

Results:

In all cases reticular varices was found together with the telangiectases. In 73.5% (147/200 areas) one or more incompetent perforating veins was found (average diameter 1.6 mm) and in 83.6% (123/147 areas) it was possible to establish that the main source of reflux was in the base of the telangiectasia. Complete elimination of microvarices was achieved in 88% of cases (176/200 areas; average sessions: 3.5). The complications were haemosiderin pigmentation (1.5%, 3/200 areas) and matting (1%, 2/200 areas). In 24 areas resistant to the therapy it was not possible to demonstrate the presence of reflux, while in 24.5% of cases (49/200 areas, average surface 15.4 cm2) two sessions of sclerotherapy were sufficient eventually to obtain (about 4 weeks later) the disappearance of the micro-varices. Follow-up after 3 years revealed the appearance of new telangiectases in 58.9% of cases (109/185 check-ups). Of these 95.4% (104/109) arose in areas other than those treated and therefore only 4.6% (5/109) recurred in the area where the sclerosing treatment had been carried out.

Conclusion:

In CVI all telangiectases are accompanied by reticular varices, even when not visible on clinical examination; in most cases the sources of reflux are distinguishable as incompetent perforating veins and are situated beneath telangiectactic efflorescences.

Identification of MYC-Dependent Transcriptional Programs in Oncogene-Addicted Liver Tumors

Tumors driven by activation of the transcription factor MYC generally show oncogene addiction. However, the gene expression programs that depend upon sustained MYC activity remain unknown. In this study, we employed a mouse model of liver carcinoma driven by a reversible tet-MYC transgene, combined with chromatin immunoprecipitation and gene expression profiling to identify MYC-dependent regulatory events. As previously reported, MYC-expressing mice exhibited hepatoblastoma- and hepatocellular carcinoma-like tumors, which regressed when MYC expression was suppressed. We further show that cellular transformation, and thus initiation of liver tumorigenesis, were impaired in mice harboring a MYC mutant unable to associate with the corepressor protein MIZ1 (ZBTB17). Notably, switching off the oncogene in advanced carcinomas revealed that MYC was required for the continuous activation and repression of distinct sets of genes, constituting no more than half of all genes deregulated during tumor progression and an even smaller subset of all MYC-bound genes. Altogether, our data provide the first detailed analysis of a MYC-dependent transcriptional program in a fully developed carcinoma and offer a guide to identifying the critical effectors contributing to MYC-driven tumor maintenance. Cancer Res; 76(12); 3463-72. ©2016 AACR.

Expanding the Living Donor Pool "Second Act": Laparoscopic Donor Nephrectomy and ABO-Incompatible Kidney Transplantation Improve Donor Recruitment

BACKGROUND

To safely expand our living donor pool, we recently decided to work on 3 areas: analysis of causes of exclusion of potential donors, the results of which we recently published, introduction of laparoscopic donor nephrectomy (LDN), and ABO-incompatible (ABOi) transplantation. We sought to determine the impact of the new strategy on living donor recruitment and transplantation during over a 10-year period at a single institution.

METHODS

From January 2005 to September 2014, we evaluated 131 living donors. Of these, 80 (61%) were genetically related, 51 (39%) unrelated, 119 (91%) ABO compatible (ABOc), 12 ABOi (9%). The analysis was divided into 2 eras: era 1, 2005-2010 (n = 53) included the use of open lumbotomy and acceptance of ABOc only; and era 2, 2011-2014 (n = 78), which saw the introduction of LDN and ABOi transplantation.

RESULTS

Forty-five (34%) potential candidates successfully donated, 67 (51%) were excluded, and 19 (15%) were actively undergoing evaluation. Overall, 53 potential donors were evaluated in era 1 (8.8 donors/year), 78 in era 2 (19.5 donors/year). There were fewer excluded donors in era 2 vs era 1 (62% era 1 vs 44% era 2), and living donor kidney transplantation (LDKT) significantly increased in era 2 vs era 1 (3.3/year era 1 vs 7.1/year era 2). The establishment of an ABOi LDKT program led to a 15% increase of evaluations in era 2 (12/78 donors).

CONCLUSIONS

LDN along with ABOi LDKT allowed for an improvement in recruitment of living donors and corresponding LDKT.

Integrated Systems for NGS Data Management and Analysis: Open Issues and Available Solutions

Next-generation sequencing (NGS) technologies have deeply changed our understanding of cellular processes by delivering an astonishing amount of data at affordable prices; nowadays, many biology laboratories have already accumulated a large number of sequenced samples. However, managing and analyzing these data poses new challenges, which may easily be underestimated by research groups devoid of IT and quantitative skills. In this perspective, we identify five issues that should be carefully addressed by research groups approaching NGS technologies. In particular, the five key issues to be considered concern: (1) adopting a laboratory management system (LIMS) and safeguard the resulting raw data structure in downstream analyses; (2) monitoring the flow of the data and standardizing input and output directories and file names, even when multiple analysis protocols are used on the same data; (3) ensuring complete traceability of the analysis performed; (4) enabling non-experienced users to run analyses through a graphical user interface (GUI) acting as a front-end for the pipelines; (5) relying on standard metadata to annotate the datasets, and when possible using controlled vocabularies, ideally derived from biomedical ontologies. Finally, we discuss the currently available tools in the light of these issues, and we introduce HTS-flow, a new workflow management system conceived to address the concerns we raised. HTS-flow is able to retrieve information from a LIMS database, manages data analyses through a simple GUI, outputs data in standard locations and allows the complete traceability of datasets, accompanying metadata and analysis scripts.

Hemodynamic overload and intra-abdominal adiposity in obese children: Relationships with cardiovascular structure and function

BACKGROUND AND AIMS

Childhood obesity promotes adverse changes in cardiovascular structure and function. This study evaluated whether these changes are related to intra-abdominal adiposity and associated cardiometabolic risk or to body-size induced hemodynamic overload.

METHODS AND RESULTS

55 obese children/adolescents and 35 healthy-weight controls underwent carotid, cardiac and abdominal ultrasound to assess carotid artery intima-media thickness (IMT), diameter, distension and stiffness, left ventricular (LV) dimension, mass and function and extent of intra-abdominal adiposity. As compared to controls with healthy BMI, obese children had higher systolic blood pressure (BP), stroke volume and lower total peripheral resistance (P < 0.001-0.0001), higher plasma triglycerides, glycated hemoglobin, insulin and HOMA-IR index (P = 0.01-<0.0001), higher carotid IMT, diameter and distension (P < 0.005-0.0005), higher LV diameter, wall thickness and mass (P < 0.001-0.0001), and impaired LV diastolic function assessed by myocardial longitudinal performance (P < 0.005). In entire population, independent determinants of carotid diameter, LV diameter, wall thickness and mass were fat-free mass (or stroke volume, respectively) and BP. Carotid distension was determined by carotid diameter and BP, and carotid IMT by carotid diameter, BP, HDL-cholesterol and glycated hemoglobin. LV diastolic performance was inversely related to preperitoneal fat thickness and plasma insulin levels.

CONCLUSIONS

Obese youths present signs of impaired lipid and glucose metabolism, hyperdynamic circulation and cardiovascular changes. Increase in LV dimensions and mass and in carotid diameter and distension seems to reflect adaptation to body-size induced increase in hemodynamic load, changes in LV diastolic performance a negative impact of intra-abdominal adiposity and associated metabolic risk, and increase in IMT both adaptive remodeling and metabolic risk.

Monoamine oxidase A polymorphism moderates stability of attention problems and susceptibility to life stress during adolescence

Attention problems affect a substantial number of children and adolescents and are predictive of academic underachievement and lower global adaptive functioning. Considerable variability has been observed with regard to the individual development of attention problems over time. In particular, the period of adolescence is characterized by substantial maturation of executive functioning including attentional processing, with the influence of genetic and environmental factors on individual trajectories not yet well understood. In the present investigation, we evaluated whether the monoamine oxidase A functional promoter polymorphism, MAOA-LPR, plays a role in determining continuity of parent-rated attention problems during adolescence. At the same time, a potential effect of severe life events (SLEs) was taken into account. A multi-group path analysis was used in a sample of 234 adolescents (149 males, 85 females) who took part in an epidemiological cohort study at the ages of 11 and 15 years. Attention problems during early adolescence were found to be a strong predictor of attention problems in middle adolescence. However, in carriers of the MAOA-LPR low-activity variant (MAOA-L), stability was found to be significantly higher than in carriers of the high-activity variant (MAOA-H). Additionally, only in MAOA-L carriers did SLEs during adolescence significantly impact on attention problems at the age of 15 years, implying a possible gene × environment interaction. To conclude, we found evidence that attention problems during adolescence in carriers of the MAOA-L allele are particularly stable and malleable to life stressors. The present results underline the usefulness of applying a more dynamic GxE perspective.

Abstract A39: The mitochondrial translation machinery is a critical effector of Myc in lymphomagenesis

The Myc protein, encoded by the c-myc proto-oncogene, is a transcription factor that binds thousands of genomic loci. Based on genome-wide binding and expression profiles, we recently provided an exhaustive list of genes that are up- or down-regulated by Myc during B-cell lymphomagenesis in Eµ-myc transgenic mice (Sabò et al. 2014 Nature 511, 488-492). Which among those Myc-regulated genes are critical effectors in tumor progression and maintenance remained largely unknown. Here, we show that concerted activation by Myc of the mitochondrial translation machinery is critical for the maintenance of Myc-induced lymphomas. A majority of genes encoding for Mitochondrial Ribosomal Proteins (MRPs) and other associated polypeptides were directly up-regulated by Myc in Eµ-myc lymphomas. Among those was the gene encoding PTCD3, a Pentatricopeptide repeat protein involved in mitochondrial translation (Davies et al. 2009 FEBS Lett. 583, 1853-1858). RNAi-based knockdown of PTCD3 or several MRPs conferred a selective disadvantage in lymphoma cells, owing to impaired cell proliferation. As expected PTCD3 knockdown in lymphomas was also accompanied by a reduction in the levels of mitochondrial-encoded protein COX-I. Chemical inhibition of mitochondrial translation with Tigecycline led to rapid death of Eµ-myc lymphoma cells in vitro. We are currently testing the effect of Tigecycline on lymphoma growth in vivo.

Citation Format: Aleco D'Andrea, Valerio Bianchi, Paola Nicoli, Bruno Amati. The mitochondrial translation machinery is a critical effector of Myc in lymphomagenesis. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A39.

Elderly kidney transplant recipient with intermittent fever: a case report of leishmaniasis with acute kidney injury during liposomal amphotericin B therapy

We present a case report of visceral leishmaniasis in an elderly kidney transplant recipient (age, 73 years) with high intermittent fever in the 2 months before admission. Symptoms started 16 years after transplant. The patient received appropriate treatment with liposomal amphotericin and experienced transient increases in serum creatinine levels. Progression to dialysis was avoided with short duration of therapy (5 consecutive days, plus 1 more dose 1 week apart, a schedule alternative to 15-21 days [supported by the literature]) and a temporary reduction in tacrolimus exposure. After 4 months, recurrence of symptoms without other explanation required a second bone marrow aspirate; it revealed the persistence of amastigote forms. Visceral leishmaniasis is a potentially life-threatening infection; to the best of our knowledge, this is the oldest transplanted patient with a case of leishmaniasis described in the literature.

Efficacy and safety of dabigatran in a "real-life" population at high thromboembolic and hemorrhagic risk: data from MonaldiCare registry

OBJECTIVE

Dabigatran is a novel target specific oral anticoagulant for stroke prevention in non valvular atrial fibrillation. Little is still known about its real-world effectiveness and safety in the italian population. Aim of our study was to evaluate the efficacy and safety of dabigatran in a large single-center cohort of "real-life" italian population with non-valvular AF and to compare the results with those obtained from the RE-LY trial and the Medicare study.

PATIENTS AND METHODS

We studied a prospective cohort of 2108 patients (1119 male; mean age 69.4 ± 9.4 years) who started the oral anticoagulant treatment with dabigatran 110 mg twice-daily (DAB 110; N = 1075; 51%) or 150 mg twice-daily (DAB 150; N = 1033; 49%). Follow-up data were obtained trough outpatients visits each 3-6 months for assessing the clinical status, adherence to treatment, occurrence of side effects and major cardiovascular complications.

RESULTS

In DAB 150 group the mean age was 64.9 ± 8.8 years, 56.8% of patients was male. CHA2DS2Vasc Score was ≥ 3 in 94.3% and HAS-BLED was ≥ 3 in 59.7%. In DAB 110 group (N = 1075) the mean age was 73.9 ± 7.5 years; 49.5% of patients was male. CHA2DS2Vasc Score was ≥ 3 in 73.4% and HAS-BLED was ≥ 3 in 87.4% of DAB 110 patients. One patient taking Dabigatran 110 mg bid had ischemic stroke without significantly neurological sequelae. In both groups, no patient experienced hemorrhagic stroke during the follow-up period. 147 patients (6.9%) of MonaldiCare population reported adverse effects from treatment with dabigatran, of whom 121 patients (5.7%) discontinued therapy. We reported one case of subarachnoid hemorrhage (0.05%) in a patient with high thrombo-embolic and high hemorrhagic risk score who was taking dabigatran 150 mg bid and one case (0.05%) of bladder bleeding in a patient who was taking dabigatran 110 mg bid. No major gastrointestinal bleeding was observed in the MonaldiCare population.

CONCLUSIONS

MonaldiCare registry showed a safety profile of both dosages of dabigatran regarding major of fatal bleeding in a "real life" single center italian population at high thromboembolic and hemorrhagic risk. The majority of MonaldiCare patients tolerated dabigatran treatment without significant side effects. The efficacy of dabigatran was demonstrated by very low prevalence of ictus/TIA, also when patients underwent electrical AF cardioversion independently of the transesophageal examination.

Abstract A47: Gene regulation by Myc during B cell activation

Myc is required for the response of cells to proliferative stimuli, as shown for example in fibroblasts or B-cells. Cellular activation entails the regulation of specific transcriptional programs concomitant with a general increase in RNA production (also termed “amplification”), which will need to be carefully disentangled for a full understanding of the mitogenic response. Upon activation of quiescent fibroblasts with serum, c-myc is rapidly induced, and is required for the subsequent activation of a set of ca. 300 genes (Myc-Dependent Serum Response, or MDSR genes) in the early-mid G1 phase of the cell cycle (1). This is followed by RNA amplification, concomitant with the G1-S transition (2). Deletion of the c-myc gene prior to serum stimulation led to a loss of all of these responses: these data indicated that Myc primarily acts to selectively regulate specific gene programs, with RNA amplification occurring as a secondary consequence (2). This is in apparent contrast with previous studies on B-cells and tumors, in which Myc was proposed to directly drive transcriptional amplification at all active loci (3, 4). Here, we addressed Myc-dependent responses in primary mouse B-cells, based on conditional deletion of c-myc followed by LPS stimulation. Our data indicate that, as in fibroblasts, a discrete set of Myc-dependent genes can be identified in B-cells: the response of these genes occurs prior to general RNA amplification, and is not entirely attributable to overt promoter/enhancer invasion by Myc. Together with our previous studies (see poster by A. Sabò et al.) (2), these data provide a unifying view of Myc' s action in different cell types, with amplification occurring as an indirect effect, following from the action of specific Myc-target genes on cellular physiology and metabolism. Systematic work is needed to unravel which of the numerous Myc-regulated genes are critical in mediating this chain of events.

References:

1. Perna D, et al. (2012) Genome-wide mapping of Myc binding and gene regulation in serum-stimulated fibroblasts. Oncogene 31, 1695-1709.

2. Sabo A, et al. (2014) Selective transcriptional regulation by Myc in cellular growth control and lymphomagenesis. Nature 511, 488-492.

3. Nie Z, et al. (2012) c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells. Cell 151, 68-79.

4. Lin CY, et al. (2012) Transcriptional amplification in tumor cells with elevated c-Myc. Cell 151, 56-67.

Citation Format: Alessandra Tesi, Arianna Sabò, Valerio Bianchi, Marco Morelli, Mattia Pelizzola, Bruno Amati. Gene regulation by Myc during B cell activation. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A47.

Abstract A44: Selective transcriptional regulation by Myc in growth control and tumorigenesis

Myc binds DNA with a preference for the E-box consensus CACGTG. In vivo, however, DNA recognition is primarily determined by chromatin context, preceding sequence-specific DNA binding. Myc preferentially associates with active/poised promoters and, to a lesser extent, distal enhancer elements. When expressed at high levels, Myc targets virtually all active promoters and enhancers in the genome, a phenomenon termed “invasion”, which contributed to the concept that Myc acts as a general amplifier of transcriptional activity (1, 2). We recently presented data that support a different scenario (3). While Myc has the potential to interact with all active/poised regulatory elements in the genome, this does not systematically lead to a productive regulatory interaction: instead, promoter/enhancer invasion by Myc most likely reflects the detection of low-affinity interactions (protein-protein or protein-DNA) that allow the transcription factor to target the relevant genomic regions, preceding local scanning of the DNA sequence for high-affinity binding sites (4). Most importantly, when productively engaged by Myc, target genes can be either induced or repressed, as shown in different cell types (3, 5). Our data also show that the global increase in mRNA copies per cell (or amplification), observable either during tumor progression or upon mitogenic stimulation of normal cells, can occur in the absence of overt promoter/enhancer invasion by Myc. RNA amplification is thus indirect, most likely attributable to changes in physiological features that impact on global RNA production and turnover (e.g. cell size, energy metabolism, etc..). Consistent with this view, many Myc-regulated genes have - or may have - central roles in these physiological processes. Putting together all available data, the emerging unifying model supports a central role for Myc in the control of cellular physiology and metabolism, including - albeit indirectly - global RNA production and turnover. An important challenge lying ahead is the full characterization of the Myc-regulated genes and pathways that mediate these biological effects and - by the same token - endow Myc with such pervasive oncogenic potential. 1. Lin CY, et al. (2012) Transcriptional amplification in tumor cells with elevated c-Myc. Cell 151:56-67. 2. Nie Z, et al. (2012) c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells. Cell 151:68-79. 3. Sabo A, et al. (2014) Selective transcriptional regulation by Myc in cellular growth control and lymphomagenesis. Nature 511:488-492. 4. Sabo A & Amati B (2014) Genome Recognition by MYC. Cold Spring Harb Perspect Med 4. 5. Walz S, et al. (2014) Activation and repression by oncogenic MYC shape tumour-specific gene expression profiles. Nature 511:483-487.

Citation Format: Arianna Sabò, Theresia K. Kress, Mattia Pelizzola, Stefano de Pretis, Marcin Gorski, Alessandra Tesi, Marco J. Morelli, Pranami Bora, Mirko Doni, Alessandro Verrecchia, Claudia Tonelli, Giovanni Fagà, Valerio Bianchi, Alberto Ronchi, Diana Low, Heiko Muller, Ernesto Guccione, Stefano Campaner, Bruno Amati. Selective transcriptional regulation by Myc in growth control and tumorigenesis. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A44.

Abstract A27: Epigenomic and transcriptional analyses in a Tet-Myc driven mouse model of liver cancer

The c-myc proto-oncogene is frequently overexpressed in human hepatoblastoma due to gene amplification or constitutively active Wnt signaling. High Myc levels characterize an aggressive hepatoblastoma subtype, reproduced in mice with a liver-specific tetracyclin-regulated c-myc transgene (1, 2). Here, we used an analogous mouse model (tetO-MYC/Lap-tTA; ref. 3) to study the epigenomic and transcriptional mechanisms underlying tumor progression and maintenance. Tet-Myc induction in utero resulted in rapid and fully penetrant tumorigenesis by the age of six weeks. Pre-tumoral changes were detectable already at a late embryonic stage (E18.5) with increased liver size and hepatoblast fraction. As previously described (2), tumors remained dependent on the constitutive expression of the transgene. To study transcriptional changes during tumor progression and regression, we established RNA-seq profiles in control hepatoblasts, pre-tumoral Tet-Myc hepatoblasts and tumor nodules, in the latter before and after short-term inactivation of Tet-Myc. In parallel, we used ChIP-seq to profile the genome-wide distribution of Myc, RNAPII and several histone marks (H3K4me1, H3K4me3, H3K27ac), yielding comprehensive maps of Myc binding to regulatory elements (promoters and enhancers). This unique dataset is providing the basis for mechanistic studies addressing how Myc deregulates its target genes during liver tumorigenesis: comparison of differentially expressed mRNAs and Myc-binding profiles enables us to discriminate between directly and potentially indirectly regulated genes, for which we are currently investigating the underlying molecular basis. Furthermore, our genome-wide data are allowing us to unravel potentially druggable genes and pathways regulated by Myc during hepatoblastoma progression and maintenance. Our progress in characterizing this model will be presented at the meeting.

References:

1. Cairo S et al. 2008, Cancer Cell, 14:471-84

2. Shachaf CM et al. 2004, Nature, 431:1112-7

3. van Riggelen J et al. 2010, Genes Dev, 24:1281-94

Citation Format: Theresia Kress, Valerio Bianchi, Luana D'Artista, Paola Nicoli, Mirko Doni, Enrico Radaelli, Bruno Amati. Epigenomic and transcriptional analyses in a Tet-Myc driven mouse model of liver cancer. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A27.

methylPipe and compEpiTools: a suite of R packages for the integrative analysis of epigenomics data

BACKGROUND

Numerous methods are available to profile several epigenetic marks, providing data with different genome coverage and resolution. Large epigenomic datasets are then generated, and often combined with other high-throughput data, including RNA-seq, ChIP-seq for transcription factors (TFs) binding and DNase-seq experiments. Despite the numerous computational tools covering specific steps in the analysis of large-scale epigenomics data, comprehensive software solutions for their integrative analysis are still missing. Multiple tools must be identified and combined to jointly analyze histone marks, TFs binding and other -omics data together with DNA methylation data, complicating the analysis of these data and their integration with publicly available datasets.

RESULTS

To overcome the burden of integrating various data types with multiple tools, we developed two companion R/Bioconductor packages. The former, methylPipe, is tailored to the analysis of high- or low-resolution DNA methylomes in several species, accommodating (hydroxy-)methyl-cytosines in both CpG and non-CpG sequence context. The analysis of multiple whole-genome bisulfite sequencing experiments is supported, while maintaining the ability of integrating targeted genomic data. The latter, compEpiTools, seamlessly incorporates the results obtained with methylPipe and supports their integration with other epigenomics data. It provides a number of methods to score these data in regions of interest, leading to the identification of enhancers, lncRNAs, and RNAPII stalling/elongation dynamics. Moreover, it allows a fast and comprehensive annotation of the resulting genomic regions, and the association of the corresponding genes with non-redundant GeneOntology terms. Finally, the package includes a flexible method based on heatmaps for the integration of various data types, combining annotation tracks with continuous or categorical data tracks.

CONCLUSIONS

methylPipe and compEpiTools provide a comprehensive Bioconductor-compliant solution for the integrative analysis of heterogeneous epigenomics data. These packages are instrumental in providing biologists with minimal R skills a complete toolkit facilitating the analysis of their own data, or in accelerating the analyses performed by more experienced bioinformaticians.