Immortalization and transformation of primary cells mediated by engineered ecDNAs

Focal gene amplifications are among the most common cancer-associated mutations, but their evolution and contribution to tumorigenesis have proven challenging to recapitulate in primary cells and model organisms. Here we describe a general approach to engineer large (>1 Mbp) focal amplifications mediated by extrachromosomal circular DNAs (ecDNAs, also known as "double minutes") in a spatiotemporally controlled manner in cancer cell lines and in primary cells derived from genetically engineered mice. With this strategy, ecDNA formation can be coupled with expression of fluorescent reporters or other selectable markers to enable the identification and tracking of ecDNA-containing cells. We demonstrate the feasibility of this approach by engineering MDM2-containing ecDNAs in near-diploid human cells, showing that GFP expression can be used to track ecDNA dynamics under physiological conditions or in the presence of specific selective pressures. We also apply this approach to generate mice harboring inducible Myc - and Mdm2 -containing ecDNAs analogous to those spontaneously occurring in human cancers. We show that the engineered ecDNAs rapidly accumulate in primary cells derived from these animals, promoting proliferation, immortalization, and transformation.

Prediction of congestive state and prognosis in acute and chronic heart failure: the association between NT-proBNP and left atrial strain

Background

In acute and chronic heart failure (HF), the relief of congestion is one of the pivotal elements to improve patient's quality of life and prognosis. N-terminal pro-brain natriuretic peptide (NT-proBNP) is a well-known marker of cardiovascular congestion in HF, although with limited specificity. Peak atrial longitudinal strain (PALS) by speckle tracking echocardiography is emerging as an index of left ventricular (LV) filling pressure and prognosis in HF, however, its role as a marker of congestion should be further elucidated.

Purpose

the aim of our study was to determine the association between NT-proBNP and PALS and their prognostic implications in patients acute and chronic HF.

Methods

patients hospitalized for de-novo or recurrent acute HF and patients with chronic HF referred to our echo-labs for follow-up evaluation were included in this retrospective study. Patients with missing data, previous cardiac surgery, heart transplant and/or left ventricular assist device implantation, non-feasible speckle tracking analysis were excluded. Clinical characteristics, laboratory examinations, transthoracic echocardiography data were collected. Speckle tracking analysis was performed offline on the echocardiographic records. Follow up data were obtained via electronical records or phone-calls. The primary clinical endpoint was a combination of all-cause death and HF hospitalization.

Results

the overall study cohort included 388 patients, of which 172 with acute HF and 216 with chronic HF. Mean age was 65±12, 37% were female. The majority of patients had reduced LV systolic function (mean LV ejection fraction = 30±10%; mean LV global longitudinal strain = −8.3±3.9%). Patients with acute HF presented higher values of NT-proBNP than those with chronic HF (median [interquartile range] = 6039 [2989; 13535]pg/ml vs. 544[200; 1533] pg/ml) and lower global PALS (10.4 [6.3; 16.45] vs. 15.6 [10.6; 21]%). Global PALS showed a significant inverse correlation with NT-proBNP both in acute and chronic HF (Fig. 1; all p<0.001) and to be a significant predictor of NT-proBNP with linear regression analysis (R2=0.2; p<0.001). During a median follow-up of 1 year, 98 patients reached the combined endpoint (49 all-cause deaths, 16 cardiovascular deaths, 62 HF hospitalizations). With ROC curves, both NT-proBNP and global PALS showed to be good predictors of the combined endpoint (AUC=0.87 and 0.82 respectively, Fig. 2). Kaplan-Meier analysis showed a good risk stratification for the composite endpoint for ROC-derived cut-off of PALS ≤15% and NTproBNP ≥874.5%, and above all for their combination (Fig. 1B)

Conclusions

global PALS is associated with NT-proBNP in acute and chronic HF and may be used as additional index of congestion to optimize therapeutic management in these patients. The combination of global PALS and NT-proBNP could enhance the prognostic stratification of HF.

Funding Acknowledgement

Type of funding sources: None.

Left ventricular myocardial work indices and invasive measurement of stroke work: a correlation study

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

A novel echocardiographic method allows to non-invasively assess myocardial work using pressure-strain loops. Even though left ventricular myocardial work has already emerged as a promising prognostic tool for various pathological conditions, its relationship with invasively-derived corresponding indices has not been assessed in humans yet.

PURPOSE

This study aimed to explore the correlation between left ventricular myocardial work (LVMW) indices and invasively-derived left ventricular stroke work index (LVSWI) in a cohort of patients with advanced heart failure (HF) considered for heart transplantation.

METHODS

All consecutive patients with advanced heart failure considered for heart transplantation from 2016 to 2021 that had already performed right heart catheterization (RHC) as part of the workup and with an available echocardiographic exam were included (n = 91). Myocardial work analysis was performed in 44 patients, according to exclusion criteria. Conventional LV functional parameters and LVMW indices, including LV global work index (LVGWI), LV global constructive work (LVGCW), LV global wasted work (LVGWW), LV global work efficiency (LVGWE) and other were calculated and compared with invasively measured LV stroke work index (LVSWI).

RESULTS

Median time between RHC and echocardiography was 0 months [interquartile range (IQR): 0 – 1]. Median age was 60 years (IQR: 54 – 63). For the most part, etiology of HF was non-ischemic (61.4%) and all patients were either on class NYHA II (61.4%) or III (27.3%). Median left ventricular ejection fraction was 25% (IQR: 22.3 – 32.3), median NT-proBNP 1377 pg/mL (IQR: 646 – 2570). Among conventional parameters of LV function, LV global longitudinal strain (LVGLS) significantly correlated with LVSWI (r = - 0.337; p = 0.031), whereas LVEF did not (r = 0.308; p = 0.050). With regard to LVMW indices, some of them demonstrated correlation with LVSWI, particularly LVGWI (r = 0.425; p = 0.006), LVGCW (r = 0.506; p = 0.001), LV global positive work (LVGPW; r = 0.464; p = 0.003) and LV global systolic constructive work (LVGSCW; r = 0.471; p = 0.002).

CONCLUSIONS

Among left ventricular myocardial work indices, LVGCW correlated better with invasively-derived stroke work, thus representing a powerful and reliable tool for a more comprehensive evaluation of myocardial function. Abstract Figure. Study flow chart  Abstract Figure. Correlation results

Clinical, echocardiographic and hemodynamic predictors of right heart failure after LVAD placement

Right ventricular failure (RVF) after left ventricular assist device (LVAD) implant is associated with increasing morbidity and mortality. The aim of this study was to identify the best predictors of RVF post LVAD-implant among biochemical, haemodynamic and echocardiographic parameters. From 2009 to 2019, 38 patients who underwent LVAD implantation at our centre were prospectively enrolled. Preoperative clinical, laboratory, echocardiographic and haemodynamic parameters were reported. Overall, eight patients (21%) developed RVF over time, which revealed to be strongly related to overall mortality. Pulmonary artery pulsatility index (PAPi) resulted to be the most significant right heart catheterization index in discriminating RVF vs no RVF patients [(1.32 ± 0.26 vs. 3.95 ± 3.39 respectively) p = 0.0036]. Regarding transthoracic echocardiography, RVF was associated with reduced free wall right ventricular longitudinal strain (fw-RVLS) (- 7.9 ± 1.29 vs. - 16.14 ± 5.83) (p < 0.009), which was superior to other echocardiographic determinants of RVF. Among laboratory values, N-terminal pro-brain natriuretic peptide (NT-proBNP) was strongly increased in RVF patients [(10,496.13 pg/ml ± 5272.96 pg/ml vs. 2865, 5 pg/ml ± 2595.61 pg/ml) p = 0.006]. PAPi, NT-proBNP and fwRVLS were the best pre-operative predictors of RVF, a post-LVAD implant complication which was confirmed to have a great impact on survival. In particular, fwRVLS has been proven to be the strongest independent predictor.

Left atrial strain as a pre-operative prognostic marker for patients with severe primary mitral regurgitation

Background

For patients with severe mitral regurgitation (MR), new indices are needed to optimize surgical timing before irreversible myocardial dysfunction.

Purpose

We investigated the prognostic role of left atrial (LA) strain by speckle tracking echocardiography after mitral surgery for severe MR, and its association with LA fibrosis.

Methods

70 patients with primary severe MR undergoing echocardiography before mitral surgery were enrolled. Patients with other valvular disease &gt; moderate, left bundle branch block, coronary artery disease, heart failure (HF), pacemaker implantation, heart transplantation, poor acoustic window, were excluded. The primary composite endpoint included HF and mortality; the secondary endpoint was post-operative functional capacity (NYHA and Borg CR10). LA fibrosis was assessed by atrial biopsy specimens.

Results

Of 62 patients eligible, 32 had composite events (medium follow-up: 3.3±2.5 years for event-group, 7.6±1 years for non-event group). Characteristics of our study population are summarized in Table 1. With Kaplan-Meier analysis (Fig. 1), PALS provided a good risk stratification; it also was an independent and incremental predictor of outcome in four multivariate Cox adjusted models. There was a strong association between PALS and secondary endpoint (NYHA: r2=0.11, p=0.04; Borg CR10: r2=0.10, p=0.02) and an inverse correlation between PALS &lt;21% and LA fibrosis (r2=0.80; 76.6±20.7% vs 31.9±20.8%; p&lt;0.0001).

Conclusions

Global PALS emerged as a reliable predictor of outcome and functional capacity for severe primary MR, and as a marker of LA fibrosis.

Figure 1

Funding Acknowledgement

Type of funding source: None

A unifying paradigm for transcriptional heterogeneity and squamous features in pancreatic ductal adenocarcinoma

Pancreatic cancer expression profiles largely reflect a classical or basal-like phenotype. The extent to which these profiles vary within a patient is unknown. We integrated evolutionary analysis and expression profiling in multiregion-sampled metastatic pancreatic cancers, finding that squamous features are the histologic correlate of an RNA-seq-defined basal-like subtype. In patients with coexisting basal and squamous and classical and glandular morphology, phylogenetic studies revealed that squamous morphology represented a subclonal population in an otherwise classical and glandular tumor. Cancers with squamous features were significantly more likely to have clonal mutations in chromatin modifiers, intercellular heterogeneity for MYC amplification and entosis. These data provide a unifying paradigm for integrating basal-type expression profiles, squamous histology and somatic mutations in chromatin modifier genes in the context of clonal evolution of pancreatic cancer.

1227 Risk stratification of patients with asymptomatic moderate mitral regurgitation: the prognostic value of left atrial strain

Background

In asymptomatic moderate mitral regurgitation (MR), the criteria for risk stratification are still uncertain. Therefore, in these patients, optimal time of surgery remains controversial.

Purpose

Our aim was to compare left atrial (LA) strain to other echocardiographic parameters for the prediction of cardiovascular (CV) events in patients with asymptomatic moderate MR.

Methods

401 patients with primary degenerative asymptomatic moderate MR was enrolled and prospectively followed for the development of CV events (i.e. atrial fibrillation, stroke/transient ischemic attack, acute heart failure, CV death). Patients with history of atrial fibrillation, myocardial infarction, heart failure, cardiac surgery or heart transplantation, severe MR, mitral valve surgery during follow-up were excluded.

Results

During a mean follow up of 3.4 ± 2 years, of the 326 patients eligible (mean age 65 ± 9 years), 122 patients had 149 new events. There were no significative differences in mean age and sex, clinical and therapeutic characteristics between the two groups. The event-group presented reduced global peak atrial longitudinal strain (PALS), LA emptying fraction, LV strain at baseline, and larger LA volume indexed (p &lt;0.0001). Receiver operating characteristics curves proved the greatest predictive performance for global PALS &lt; 35% (AUC 0.88). Bland-Altman analysis demonstrated good intra- and inter-observer agreement and Kaplan Meier analysis showed a graded association between PALS and event-free-survival.

Conclusions

Speckle tracking echocardiography could provide a useful index, global PALS, to estimate LA function in patients with asymptomatic moderate MR in order to optimize surgical timing before the development of irreversible myocardial dysfunction.

Echo-data of our study population Variable No CV events (n = 204) CV events (n = 122) LV ejection fraction (%) 59 ± 9 58 ± 10 LV global longitudinal strain (%) - 18.5 ± 3.4 -17.6 ± 3.6* LA volume indexed (ml/m2) 32.5 ± 6.7 36.4 ± 7.1* LA emptying fraction (%) 68 ± 13 62 ± 15* Mitral E/A ratio 0.94 ± 0.14 0.95 ± 0.16 Mitral E/E’ ratio 11.2 ± 6.5 12.4 ± 7.1 Mitral regurgitant fraction (%) 38.9 ± 8.1 39.1 ± 9.4 End regurgitation orifice area (cm2) 0.34 ± 0.05 0.34 ± 0.06 Global PALS (%) 32.5 ± 8.5 19.7 ± 8.1* *Significative variation between groups. Cardiovascular, CV; Left atrial, LA; Left ventricular, LV; Peak atrial longitudinal strain, PALS

Abstract 1227 Figure. Event-free survival according to PALS

The role of 3D and speckle tracking echocardiography in cardiac amyloidosis: a case report

Cardiac amyloidosis (CA) is a disorder characterized by amyloid fibrils deposition in cardiac interstitium; it results in a restrictive cardiomyopathy with heart failure (HF) and conduction abnormalities. The "gold standard" for diagnosis of CA is myocardial biopsy but possible sampling errors and procedural risks, limit it's use. Magnetic resonance (RMN) offers more information than traditional echocardiography and allows diagnosis of CA but often it's impossible to perform. We report the case of a man with HF and symptomatic bradyarrhythmia that required an urgent pacemaker implant. Echocardiography was strongly suggestive of CA but wasn't impossible to perform an RMN to confirm this hypothesis because the patient was implanted with a definitive pacemaker. So was performed a Speckle Tracking Echocardiography (STE) and a 3D echocardiography: STE allows to differentiate CA from others hypertrophic cardiomyopathy by longitudinal strain value < 12% and 3D echocardiography shows regional left ventricular dyssynchrony with a characteristic temporal pattern of dispersion of regional volume systolic change. On the basis of these results, finally was performed an endomyocardial biopsy that confirmed the diagnosis of CA. This case underlines the importance of news, noninvasive techniques such as eco 3D and STE for early diagnosis of CA, especially when RMN cannot be performed.

Right ventricular longitudinal strain and right ventricular stroke work index in patients with severe heart failure: left ventricular assist device suitability for transplant candidates

BACKGROUND

Right ventricular (RV) systolic function has a critical role in determining the clinical outcome and the success of using left ventricular assist devices in patients with refractory heart failure. RV deformation analysis by speckle tracking echocardiography (STE) has recently allowed the analysis of RV longitudinal function. Using cardiac catheterization as the reference standard, this study aimed to explore the correlation between RV longitudinal function by STE and RV stroke work index (RVSWI) among patients referred for cardiac transplantation.

METHODS

Right heart catheterization and transthoracic echo-Doppler were simultaneously performed in 47 patients referred for cardiac transplant assessment due to refractory heart failure (ejection fraction 25.1 ± 4.5%). Thermodilution RV stroke volume and invasive pulmonary pressures were used to obtain RVSWI. RV longitudinal strain (RVLS) by STE was assessed averaging RV free-wall segments (free-wall RVLS). We also calculated. Tricuspid S' and tricuspid annular plane systolic excursion (TAPSE).

RESULTS

No significant correlation was observed for TAPSE on tricuspid S' with RV stroke volume (r = 0.14 and r = 0.06, respectively). A close negative correlation between free-wall RVLS and RVSWI was found (r = -0.82; P < .0001). Furthermore, free-wall RVLS showed the highest diagnostic accuracy (area under the curve of 0.90) with good sensitivity and specificity of 95% and 91%, respectively, to predict depressed RVSWI using a cutoff value less than -11.8%.

CONCLUSIONS

Among patients referred for heart transplantation, TAPSE and tricuspid S' did not correlate with invasively obtained RVSWI. RV longitudinal deformation analysis by STE correlated with RVSWI, providing a better estimate of RV systolic performance.

Assessment of vascular function: flow-mediated constriction complements the information of flow-mediated dilatation

OBJECTIVE

To determine whether vascular function assessed by low-flow-mediated constriction (L-FMC), a novel non-invasive method, complements the information obtained with "traditional" flow-mediated dilatation (FMD).

DESIGN AND PATIENTS

In protocol 1, 12 healthy young volunteers underwent FMD and L-FMC measurements at rest and immediately after isometric exercise of the same hand. In protocol 2, 24 patients with coronary artery disease, 24 with congestive heart failure, 24 hypertensive patients and 64 healthy volunteers were enrolled to undergo L-FMC and FMD measurements.

RESULTS

In protocol 1, exercise was associated with mean (SD) increases in radial artery blood flow, diameter and L-FMC (from -5.1 (1.5)% to -7.8 (3.4)%, p<0.05), while FMD was significantly blunted (from 6.0 (2.4)% to 3.0 (3.2)%, p<0.05). In protocol 2, both FMD and L-FMC were blunted in the patient groups. Receiver operating curve analysis showed that, as compared with FMD alone, the combination of L-FMC and FMD significantly improved the sensitivity and specificity in detecting patients diagnosed with cardiovascular disease (p<0.05).

CONCLUSION

In the first protocol, FMD and L-FMC were shown to be reciprocally regulated. A blunted FMD may, in certain cases, be an expression of increased resting vascular activation and not only of impaired endothelial function. In the second protocol, a statistical approach showed that implementation of L-FMC provides a better characterisation than FMD of vascular function in cardiovascular disease. Vascular (endothelial) function is a complex phenomenon which requires a multifaceted approach; it is suggested that a combination of L-FMC and FMD will provide additive and complementary information to "traditional" FMD measurements.

Infrarenal abdominal aortic aneurysms at multi-detector row CT angiography: intravascular enhancement without a timing acquisition

In 70 patients referred for evaluation of aortoiliac aneurysm disease, multi-detector row computed tomography was performed with a uniform 25-second delay from the initiation of intravenous administration of a 150-mL bolus of contrast material at 4 mL/sec. In all patients, adequate enhancement (>200 HU) of the aorta and intense enhancement of iliofemoral runoff was achieved without venous contamination.

[Validity of electrocardiographic indices of left ventricular hypertrophy in athletes]

The Authors have evaluated the reliability of the most important electrocardiographic criteria for left ventricular hypertrophy in a group of 95 athletes. An ECG and a M- and B-mode echocardiogram have been performed in each subject; the criteria by Sokolow and Lyon, by Cornell, by Gubner, by Romhilt and Estes and by Casale have been employed to evaluate left ventricular hypertrophy. Left ventricular mass has been evaluated by the echocardiogram according to Devereux and coll. The electrocardiographic method by Casale and coll., proposed only for a few years, is based on the valuation of R wave and on the study of ventricular repolarization depending on sex and age. By this method, still now not much used in the study of athletes, a good correlation with the echocardiographic data was expected, in relation to the young age of the population. The athletes have been divided into three groups, practising aerobic sports, aerobic-anaerobic sports and power sports, according to the physiologic classification of the sports activities of Dal Monte. Using the chi-squared test, for the whole population and separately for the three groups, no significant statistical correlation has been observed. In conclusion, the results demonstrate that not only the "classic" criteria, but also the most recent ECG criteria of left ventricular hypertrophy are not reliable in evaluating left ventricular hypertrophy in trained athletes, leaving the final assessment of the real state of the cardiac chambers to echocardiography.